The objective of this paper is to analyse the performances of two controllers such as Hysteresis control (HC) and proportional integral (PI) control to control saturation level in the magnetic core of a welding transformer in a middle-frequency direct current (MFDC) resistance spot welding system(RSWS). It consists of an input converter, welding transformer, and a full-wave rectifier mounted at the transformer secondary. The unequal ohmic resistances of the two transformer’s secondary circuits and the different characteristics of the diodes of output rectifier certainly lead to the magnetic core saturation which, consequently, causes the unwanted spikes in the transformer’s primary current and over-current protection switch-off. The goal is to analyse the performance of both controllers in terms of transients, total harmonic distortion(THD) and variations in primary current and flux in the magnetic core of a welding transformer of highly nonlinear system of RSWS. The simulation study has been done in Matlab/Simulink environment and presented performance analysis. The responses shows that from the aforementioned aspects, proportional integral Controller is the better choice for controlling the saturation level in magnetic core of a welding transformer which is widely used in automobile industry welding system.
New zv zcs full bridge dc-dc converter with fuzzy & pi controlIAEME Publication
The document summarizes a new ZVZCS (zero voltage zero current switching) full bridge DC-DC converter that aims to address issues with conventional full bridge converters. It introduces the proposed converter which uses an auxiliary circuit to clamp the voltage across the output diode bridge and allow ZVS operation. The document then compares the conventional and proposed converters, outlines the operating modes of the proposed converter, and evaluates different closed loop control strategies using PI and fuzzy logic controllers to improve dynamic performance.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
Simulation of Five Level Diode Clamped Multilevel Inverterrahulmonikasharma
The power electronics device which converts DC power to AC power at required output voltage and frequency level is known as inverter. The voltage source inverters produce an output voltage or a current with levels either 0 or +ve or-ve V dc. They are known as two-level inverters. Multilevel inverter is to synthesize a near sinusoidal voltage from several levels of dc voltages. Multilevel inverter has advantage like minimum harmonic distortion. Multi-level inverters are emerging as the new breed of power converter options for high power applications. They typically synthesize the stair-case voltage waveform (from several dc sources) which has reduced harmonic content. Multi-level inverters have many attractive features, high voltage capability, reduced common mode voltages near sinusoidal outputs, low dv/dt, and smaller or even no output filter; sometimes no transformer is required at the input side, called the transformer-less solution, making them suitable for high power applications In this paper a 5-level Diode clamped multilevel inverter is developed by IGBTS using Simulink. Gating signals for these IGBTS have been generated by designing comparators. In order to maintain the different voltage levels at appropriate intervals, the conduction time intervals of IGBT have been maintained by controlling the pulse width of gating pulses[6] (by varying the reference signals magnitude of the comparator). The simulation results for 5-level and THD for the output have been identified by MATLAB/SIMULINK.
This document describes the design and implementation of a carrier-based sinusoidal pulse width modulation (SPWM) bipolar inverter. It begins with an introduction to inverters that convert DC power to AC power. It then discusses SPWM techniques in detail, including bipolar and unipolar switching methods. The document presents simulation results for a single-phase inverter using SPWM strategies. It aims to simulate and analyze the output waveforms of a SPWM inverter model in MATLAB, and examine how the modulation index affects the simulated and implemented designs.
Current transformers are used to measure high alternating currents and provide safety isolation. They work by inducing a current in the secondary winding that is proportional to the primary current passing through the transformer core. Current transformers scale down large primary currents to safer secondary currents used for instrumentation and protection devices. They are used extensively in power generation, transmission and distribution systems to monitor operations and protect equipment.
This document describes the design of a zero voltage zero current switching (ZVZCS) full bridge DC-DC converter with transformer isolation and current doubler rectifier for high power applications. The converter achieves ZVS turn-off for the lagging leg switches using the transformer leakage inductance and switch output capacitance. ZCS is achieved for the leading leg switches using an auxiliary transformer and diodes to reset the primary current. Simulation results validate the design for a 3kW load operating at 20kHz with reduced switching losses due to the soft switching techniques.
The document discusses Flexible AC Transmission Systems (FACTS) devices for enhancing power transmission. It describes several types of FACTS controllers including series controllers like the Thyristor Controlled Series Capacitor (TCSC) and shunt controllers like the Static Synchronous Compensator (STATCOM). TCSC uses thyristors to vary the capacitive reactance in series with the transmission line, enabling increased power transfer. STATCOM maintains bus voltage by injecting reactive current and has advantages over SVC like faster response and modularity.
New zv zcs full bridge dc-dc converter with fuzzy & pi controlIAEME Publication
The document summarizes a new ZVZCS (zero voltage zero current switching) full bridge DC-DC converter that aims to address issues with conventional full bridge converters. It introduces the proposed converter which uses an auxiliary circuit to clamp the voltage across the output diode bridge and allow ZVS operation. The document then compares the conventional and proposed converters, outlines the operating modes of the proposed converter, and evaluates different closed loop control strategies using PI and fuzzy logic controllers to improve dynamic performance.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
Simulation of Five Level Diode Clamped Multilevel Inverterrahulmonikasharma
The power electronics device which converts DC power to AC power at required output voltage and frequency level is known as inverter. The voltage source inverters produce an output voltage or a current with levels either 0 or +ve or-ve V dc. They are known as two-level inverters. Multilevel inverter is to synthesize a near sinusoidal voltage from several levels of dc voltages. Multilevel inverter has advantage like minimum harmonic distortion. Multi-level inverters are emerging as the new breed of power converter options for high power applications. They typically synthesize the stair-case voltage waveform (from several dc sources) which has reduced harmonic content. Multi-level inverters have many attractive features, high voltage capability, reduced common mode voltages near sinusoidal outputs, low dv/dt, and smaller or even no output filter; sometimes no transformer is required at the input side, called the transformer-less solution, making them suitable for high power applications In this paper a 5-level Diode clamped multilevel inverter is developed by IGBTS using Simulink. Gating signals for these IGBTS have been generated by designing comparators. In order to maintain the different voltage levels at appropriate intervals, the conduction time intervals of IGBT have been maintained by controlling the pulse width of gating pulses[6] (by varying the reference signals magnitude of the comparator). The simulation results for 5-level and THD for the output have been identified by MATLAB/SIMULINK.
This document describes the design and implementation of a carrier-based sinusoidal pulse width modulation (SPWM) bipolar inverter. It begins with an introduction to inverters that convert DC power to AC power. It then discusses SPWM techniques in detail, including bipolar and unipolar switching methods. The document presents simulation results for a single-phase inverter using SPWM strategies. It aims to simulate and analyze the output waveforms of a SPWM inverter model in MATLAB, and examine how the modulation index affects the simulated and implemented designs.
Current transformers are used to measure high alternating currents and provide safety isolation. They work by inducing a current in the secondary winding that is proportional to the primary current passing through the transformer core. Current transformers scale down large primary currents to safer secondary currents used for instrumentation and protection devices. They are used extensively in power generation, transmission and distribution systems to monitor operations and protect equipment.
This document describes the design of a zero voltage zero current switching (ZVZCS) full bridge DC-DC converter with transformer isolation and current doubler rectifier for high power applications. The converter achieves ZVS turn-off for the lagging leg switches using the transformer leakage inductance and switch output capacitance. ZCS is achieved for the leading leg switches using an auxiliary transformer and diodes to reset the primary current. Simulation results validate the design for a 3kW load operating at 20kHz with reduced switching losses due to the soft switching techniques.
The document discusses Flexible AC Transmission Systems (FACTS) devices for enhancing power transmission. It describes several types of FACTS controllers including series controllers like the Thyristor Controlled Series Capacitor (TCSC) and shunt controllers like the Static Synchronous Compensator (STATCOM). TCSC uses thyristors to vary the capacitive reactance in series with the transmission line, enabling increased power transfer. STATCOM maintains bus voltage by injecting reactive current and has advantages over SVC like faster response and modularity.
Simulation of H6 full bridge Inverter for grid connected PV system using SPWM...IRJET Journal
This document proposes a new H6 full bridge inverter topology for grid-connected photovoltaic systems using sinusoidal pulse width modulation (SPWM) technique. It aims to reduce common mode leakage currents compared to existing H5 and HERIC inverter topologies. The H6 topology adds two additional switches to the DC side of the full bridge inverter. SPWM pulses for the additional switches are designed to keep the common mode voltage constant during all operating modes, which effectively reduces leakage currents. The MATLAB simulation software is used to simulate the proposed H6 inverter topology and validate the concept.
The document discusses various power electronics applications including energy storage elements like inductors and capacitors, uninterruptible power supplies (UPS), and switch mode power supplies (SMPS). It describes the basic working principles of inductors, capacitors, different types of UPS systems including static and rotary, and various SMPS topologies such as forward, flyback, non-isolated, and isolated converter modes. Key applications and components of these power electronic circuits are explained in detail across multiple pages.
IRJET- A Dual Stage Flyback Converter using VC MethodIRJET Journal
This document describes a dual stage flyback converter that uses voltage control (VC) method. It consists of two flyback converters operated alternately using a PI controller. The PI controller compares the reference voltage to the feedback voltage and compensates for errors. The output of the PI controller is compared to a triangular wave to generate driving signals for synchronous rectifiers in the two converters with 180 degree phase shift. This allows reducing additional freewheeling power. The converter is simulated in MATLAB Simulink. The simulation results show it can maintain the output voltage at 35V even when a 5V disturbance is added to the 24V input voltage, demonstrating the effectiveness of the closed-loop control strategy.
This document provides information about EHV AC and DC transmission, specifically components of EHV DC systems and converter circuits. It discusses:
1) The main components of EHV DC systems include converter transformers, thyristor valves, bus bars, and series reactors. Converters use thyristor valves connected in a three-phase full-wave bridge circuit to convert AC to DC and vice versa.
2) Converters require reactive power, which is supplied by AC filters, shunt capacitors or synchronous condensers. Operation of converters generates harmonic voltages and currents that can cause equipment heating, interference, and other issues if not mitigated.
3) Harmonics are mitigated using AC and DC
Report On diode clamp three level inverterVinay Singh
three level diode clamp inverter. that converts any type of DC ( rectified, PV cell, battery etc.) to AC supply. we made by mosfet and ardiuno . in this ppt we present the Simulink model of a three-level inverter and the hardware reort of the inverter.
also discuss about other level inverter and there THD analysis, simulink model and detail. compression between another inverter.
This document discusses different types of multilevel inverters. It begins by introducing multilevel inverters and their advantages over traditional PWM inverters, such as lower switching frequencies and electromagnetic interference. It then describes the main types of multilevel inverters: diode-clamped, flying capacitor, cascaded H-bridge, and some other topologies. For each type, it provides a brief overview and example circuit diagrams. The document concludes by listing references for further reading on multilevel inverter research.
Fuzzy logic Control & Minimizing Commutation Torque Ripple for Brushless DC M...Editor IJMTER
Brushless dc motor still suffers from commutation torque ripple, which mainly depends
on speed and transient line current in the commutation interval. This paper presents a novel circuit
topology and a dc link voltage control strategy to keep incoming and outgoing phase currents
changing at the same rate during commutation. A dc–dc single-ended primary inductor converter
(SEPIC) and a switch selection circuit are employed in front of the inverter. The desired
commutation voltage is accomplished by the SEPIC converter. The dc link voltage control strategy is
carried out by the switch selection circuit to separate two procedures, adjusting the SEPIC converter
and regulating speed. The cause of commutation ripple is analyzed, and the way to obtain the desired
dc link voltage is introduced in detail. Finally, simulation and experimental results show that,
compared with the dc–dc converter, the proposed method can obtain the desired voltage much faster
and minimize commutation torque ripple more efficiently at both high and low speeds and the closed
loop control is achieved by Fuzzy logic control.
IRJET- Integrated Variable Resistor using Switched Capacitor Circuit and Volt...IRJET Journal
The document proposes a method to fabricate a voltage-controlled variable resistor in an integrated circuit using a switched capacitor circuit with a varactor tuning circuit. It summarizes how switched capacitor circuits can simulate resistance using ideal switches and a capacitor. A varactor diode acts as a variable capacitor under reverse bias, allowing the capacitance and resistance to be controlled by voltage. The document simulates the proposed circuit in LTSPICE and shows that it achieves variable resistance by changing the control voltage and thus the capacitance of the tuning circuit.
Common Mode Voltage Control in Three Level Diode Clamped InverterIJERA Editor
This paper presents simple sinusoidal PWM technique to reduced common mode voltage (CMV) at output terminal of the inverter. Multilevel inverter (MLI) is more suitable in high & medium power application, CMV is produced at the time of operation in output terminal of inverter. In this paper, an approach to reduced CMV at output terminal of MLI by using SPWM technique in three level diode clamped inverter (DCMLI) is proposed. A good transaction between the quality of the output voltage & the magnitude of CMV is achieved in this paper. The paper presents phase opposition & phase opposition disposition SPWM technique to reduced CMV in DCMLI. Simulation & experimental result presented to confirm the effectiveness of the proposed technique to control CMV.
1. The document discusses control strategies for EHV AC and DC transmission systems, including desired features of HVDC system control, control characteristics of constant current and constant extinction angle, and parallel operation of AC and DC systems.
2. Control of HVDC systems is achieved through control of current or voltage to maintain a constant voltage in the DC link. Common control modes include constant current control at the rectifier and constant extinction angle control at the inverter.
3. Parallel operation of AC and DC systems can present problems but also advantages; control coordination is needed between the two different transmission types.
A Three Level Single Stage PFC Converter for Variable Power Applicationspaperpublications3
Abstract: AC/DC power converters are required to operate with high power factor (PF) and low total harmonic distortion (THD) for improved grid quality and full capacity utilization of the transmission lines. Passive PF correction (PFC) circuits consist of inductive and capacitive filters followed by a diode bridge. They provide the simplest way of achieving high PF with high efficiency; however, they require low line frequency filters which are bulky and heavy. This work presents a new single stage three level isolated AC/DC PFC converter for high DC link voltage low-power applications achieved through an effective integration of AC/DC and DC/DC stages where all of the switches are shared between two operations. With the converter and switching scheme, input current shaping and output voltage regulation can be achieved simultaneously without introducing additional switches or switching actions. Due to the flexible DC link voltage structure, high power factor can be achieved at high line voltage. The performance of the single stage PFC converter is simulated in MATLAB/SIMULINK environment.
Keywords: Power Factor (PF), DC Link Voltage, Power Factor Correction Circuits (PFC).
Title: A Three Level Single Stage PFC Converter for Variable Power Applications
Author: Litty Joseph, Prof. Neetha John, Prof. Emmanuel Babu P
ISSN 2349-7815
International Journal of Recent Research in Electrical and Electronics Engineering (IJRREEE)
Paper Publications
Multi Carrier based Multilevel Inverter with Minimal Harmonic DistortionIJPEDS-IAES
This paper presents performance features of Asymmetric Cascaded
Multilevel inverter. Multilevel inverters are commonly modulated by using
multicarrier pulse width modulation (MCPWM) techniques such as phaseshifted
multicarrier modulation and level-shifted multicarrier modulation.
Amongst these, level-shifted multicarrier modulation technique produces the
best harmonic performance. This work studies about multilevel inverter with
unequal DC sources using level shifting MCPWM technique. The
Performances indices like Total Harmonic Distortion (THD), number of
switches and DC Sources are considered. A procedure to achieve an
appropriate level shifting is also presented is this paper.
This document summarizes a MATLAB simulation of an SPWM inverter using bipolar and unipolar switching strategies. The objective is to analyze the output voltage using FFT. It describes how the SPWM technique works by comparing a reference sine wave to a high frequency triangular carrier wave to generate PWM signals. Circuit diagrams and output waveforms are shown for both bipolar and unipolar inverters, and FFT analysis is performed. The conclusion is that a unipolar inverter with a filter provides a more sinusoidal output waveform than a bipolar inverter.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
High Power Density Multi-Mosfet-Based Series Resonant Inverter for Induction ...IAES-IJPEDS
Induction heating application uses uniquely high frequency series resonant
inverter for achieving high conversion efficiency. The proposed work focus
on improving the practical constraints in requiring the cooling arrangements
necessary for switching devices used in resonant inverter due to higher
switching and conduction losses. By introducing high frequency Multi-
MOSFET based series resonant inverter for the application of induction
heating with the following merits such as minimum switching and
conduction losses using low voltage grade of automotive MOSFET’s and
higher conversion efficiency with high frequency operation. By adding series
combination of low voltage rated Multi MOSFET switches, temperature
variation according to the on-state resistance issues can be avoided by
sharing the voltage across the switches depends on the number of switches
connected in the bridge circuit without comprising existing systems
performance parameters such as THD, power factor and output power.
Simulation results also presents to verify that the proposed system achieve
higher converter efficiency.
Abstract: Energy from the sun and the wind can alleviate the pressure on traditional sources that has been considerably depleted. Many stages of renewable energy conversion require DC-DC converters with high voltage gain and high power. The applications where electrical isolation is not necessary, transformer less high gain converters can be used in order to avoid the difficulty of using large capacity transformers. This is a step up resonant converter which can achieve high voltage-gain using LC parallel resonant tank. Zero-voltage-switching (ZVS) of semiconductor devices in a resonant converter can be achieved by resonant devices. It is characterized by ZVS turn-on and nearly ZVS turn-off of main switches. Moreover, the equivalent voltage stress of the semiconductor devices is lower than other resonant step up converters. A resonant converter is simulated using MATLAB/SIMULINK and experimental results are also verified.
Keywords: Frequency Modulation, Resonant Converter, Zero Voltage Switching, Voltage Stress.
Title: Variable Switching Frequency Based Resonant Converter
Author: Anooja Shahul, Prof. Annie P Oommen, Prof. Sera Mathew
ISSN 2349-7815
International Journal of Recent Research in Electrical and Electronics Engineering (IJRREEE)
Paper Publications
This document presents a new voltage sag compensation scheme that uses a pulse width modulation (PWM) switched autotransformer. The proposed scheme aims to maintain the rated voltage at critical load terminals during voltage sag events. It consists of an IGBT switch and autotransformer connected in series with the load. During normal operation, the thyristors bypass the compensator and supply power directly to the load. During a sag, the IGBT is controlled by PWM pulses to inject the missing voltage and regulate the load voltage. Simulation results in MATLAB/Simulink show the performance of the three-phase compensator under different sag and swell conditions. The proposed approach has fewer switching devices and good compensating capability compared to other common compensators.
Multilevel inverters (MLI) are becoming more popular over the years for medium and high power applications because of its significant merits over two level inverters. This paper presents an implementation of multicarrier based sinusoidal pulse width modulation technique for three phase seven level diode clamped multilevel inverter. This topology is operated under phase opposition disposition pulse width modulation technique. The performance of three phase seven level diode clamped inverter is analyzed for induction motor (IM) load. Simulation is performed using MATLAB/SIMULINK. Experimental results are presented to validate the effectiveness of the operation of the diode clamped multilevel inverter using field programmable gate array.
Design and Simulation of Low Pass Filter for Single phase full bridge Inverte...IJERA Editor
Sinusoidal pulse width modulation SPWM technique is widely preferred to other modulation techniques as the
Inverter output frequency obtained is equal to the required fundamental frequency. SPWM with unipolar voltage
switching is used as it results in cancellation of harmonic component at the switching frequencyin the output
voltage, also the sidebands of the switching frequency harmonics disappear and in addition to this, other
dominant harmonic at twice the switching frequency gets eliminated. Hence, due to these advantages unipolar
voltage switching with SPWMis used for Inverter switching. In this paper, an in-depth analysis of unipolar
voltage switching technique with SPWM as applied to a single-phase full bridge Inverter is described and
designing of an efficient, active low pass filter LPF is discussed for an particular cut-off frequency,푓푐 and
damping factor zeta, 휁 and the filter is placed at the output side of a single-phase full bridge Inverter and
therefore eliminating the harmonic component from the Inverter output voltage resulting in a pure sinusoidal ac
voltage waveform.
SIMULATION ANALYSIS OF CLOSED LOOP DUAL INDUCTOR CURRENT-FED PUSH-PULL CONVER...Journal For Research
The current electronic devices require DC power source, which is taken from a battery or DC power supply. DC-DC converter is utilized to get regulated dc voltage from unregulated one. Switched mode power supply (SMPS) are commonly used in industrial applications, because of more advantages compared to linear power supply. In SMPS we have isolated and non-isolated converters, where isolated converters are frequently used, in order to get more voltage with multiple outputs. So among different isolated converters, push-pull converter is chosen for micro converter applications to obtain high voltage conversion ratio by using HF transformer, due to their better utilization of transformer. New methodology of control is implemented for making ZVS and ZCS at same time and to reduce the number of switches in the secondary side of dual inductor CFPP converter, which is a voltage doubler circuit. This becomes the solution for problem identification. Thus this converter with soft-switching reduces the switching losses.The current-fed push-pull converters are used in many applications like photo-voltaic (PV) power converters for boosting the output voltage. Push-pull converter is chosen for micro converter applications, to obtain high voltage conversion ratio by using high frequency (HF) transformer, due to their better utilization of transformer. This deals with the design of dual inductor CFPP converter, where zero voltage switching (ZVS) and zero current switching (ZCS) is achieved for the primary side of the converter by using secondary switches. Primary side switches are controlled by closed loop control topology. The secondary side is made with voltage doubler to obtain high voltage. Open loop and closed loop control of dual inductor current fed push pull converter simulation is finished by MATLAB/SIMULINK and their outcomes are analyzed.
Development of magnetic pulse crimping process for highdurability connection ...IJERA Editor
Generally, hand-operated and hydraulic compressors use crimping of connection terminals. However, this equipment often causes compressed defects because non-uniform pressure is applied in the circumferential direction of the terminal during crimping. A defective terminal often leads to fire in electric equipment due to overheating. Therefore, there is a need to develop a new crimping process for manufacturing highly durable terminals. MPC (magnetic pulse crimping) uses uniform electromagnetic pressure by a high magnetic field interaction between coil and terminal. This process uses only electromagnetic pressure for crimping, so the terminal can be crimped without physical contact, thereby producing a highly durable connection terminal. In this study, a MPC process was developed to fabricate a prototypical terminal. The result was compared with other crimping processes in terms of durability. The crimped part using MPC has a lower rising temperature and higher tensile strength than those using other crimping process. It is inferred from the experimental results that an optimal charging voltage exists in the MPC process
Effect of welding parameters and tool shape on properties of friction stir we...IJERA Editor
Friction stir welding (FSW) is a widely used solid state joining process for soft materials such as aluminium alloys because it avoids many of the common problems of fusion welding. It has many benefits when applied to welding of aluminum alloys. FSW process parameters such as welding speed, rotational speed and tool geometry play vital roles in the weld quality. The aim of this research is to investigate the effects of different welding speeds, rotational speeds and tool pin profile on the weld quality of a AA6061 aluminum alloy. A friction stir welding tool consists of rotating shoulder and pin that heats the working piece by friction and moves a softened alloy around it to form a joint. In this research work the effect of the tool shape and welding parameters (rotating speed and welding speed) on the mechanical properties of an aluminium plates will be investigated experimentally. The induced heat during the welding process played the main role in the mechanical and appearance of the joints, which is related to the welding parameters.
Simulation of H6 full bridge Inverter for grid connected PV system using SPWM...IRJET Journal
This document proposes a new H6 full bridge inverter topology for grid-connected photovoltaic systems using sinusoidal pulse width modulation (SPWM) technique. It aims to reduce common mode leakage currents compared to existing H5 and HERIC inverter topologies. The H6 topology adds two additional switches to the DC side of the full bridge inverter. SPWM pulses for the additional switches are designed to keep the common mode voltage constant during all operating modes, which effectively reduces leakage currents. The MATLAB simulation software is used to simulate the proposed H6 inverter topology and validate the concept.
The document discusses various power electronics applications including energy storage elements like inductors and capacitors, uninterruptible power supplies (UPS), and switch mode power supplies (SMPS). It describes the basic working principles of inductors, capacitors, different types of UPS systems including static and rotary, and various SMPS topologies such as forward, flyback, non-isolated, and isolated converter modes. Key applications and components of these power electronic circuits are explained in detail across multiple pages.
IRJET- A Dual Stage Flyback Converter using VC MethodIRJET Journal
This document describes a dual stage flyback converter that uses voltage control (VC) method. It consists of two flyback converters operated alternately using a PI controller. The PI controller compares the reference voltage to the feedback voltage and compensates for errors. The output of the PI controller is compared to a triangular wave to generate driving signals for synchronous rectifiers in the two converters with 180 degree phase shift. This allows reducing additional freewheeling power. The converter is simulated in MATLAB Simulink. The simulation results show it can maintain the output voltage at 35V even when a 5V disturbance is added to the 24V input voltage, demonstrating the effectiveness of the closed-loop control strategy.
This document provides information about EHV AC and DC transmission, specifically components of EHV DC systems and converter circuits. It discusses:
1) The main components of EHV DC systems include converter transformers, thyristor valves, bus bars, and series reactors. Converters use thyristor valves connected in a three-phase full-wave bridge circuit to convert AC to DC and vice versa.
2) Converters require reactive power, which is supplied by AC filters, shunt capacitors or synchronous condensers. Operation of converters generates harmonic voltages and currents that can cause equipment heating, interference, and other issues if not mitigated.
3) Harmonics are mitigated using AC and DC
Report On diode clamp three level inverterVinay Singh
three level diode clamp inverter. that converts any type of DC ( rectified, PV cell, battery etc.) to AC supply. we made by mosfet and ardiuno . in this ppt we present the Simulink model of a three-level inverter and the hardware reort of the inverter.
also discuss about other level inverter and there THD analysis, simulink model and detail. compression between another inverter.
This document discusses different types of multilevel inverters. It begins by introducing multilevel inverters and their advantages over traditional PWM inverters, such as lower switching frequencies and electromagnetic interference. It then describes the main types of multilevel inverters: diode-clamped, flying capacitor, cascaded H-bridge, and some other topologies. For each type, it provides a brief overview and example circuit diagrams. The document concludes by listing references for further reading on multilevel inverter research.
Fuzzy logic Control & Minimizing Commutation Torque Ripple for Brushless DC M...Editor IJMTER
Brushless dc motor still suffers from commutation torque ripple, which mainly depends
on speed and transient line current in the commutation interval. This paper presents a novel circuit
topology and a dc link voltage control strategy to keep incoming and outgoing phase currents
changing at the same rate during commutation. A dc–dc single-ended primary inductor converter
(SEPIC) and a switch selection circuit are employed in front of the inverter. The desired
commutation voltage is accomplished by the SEPIC converter. The dc link voltage control strategy is
carried out by the switch selection circuit to separate two procedures, adjusting the SEPIC converter
and regulating speed. The cause of commutation ripple is analyzed, and the way to obtain the desired
dc link voltage is introduced in detail. Finally, simulation and experimental results show that,
compared with the dc–dc converter, the proposed method can obtain the desired voltage much faster
and minimize commutation torque ripple more efficiently at both high and low speeds and the closed
loop control is achieved by Fuzzy logic control.
IRJET- Integrated Variable Resistor using Switched Capacitor Circuit and Volt...IRJET Journal
The document proposes a method to fabricate a voltage-controlled variable resistor in an integrated circuit using a switched capacitor circuit with a varactor tuning circuit. It summarizes how switched capacitor circuits can simulate resistance using ideal switches and a capacitor. A varactor diode acts as a variable capacitor under reverse bias, allowing the capacitance and resistance to be controlled by voltage. The document simulates the proposed circuit in LTSPICE and shows that it achieves variable resistance by changing the control voltage and thus the capacitance of the tuning circuit.
Common Mode Voltage Control in Three Level Diode Clamped InverterIJERA Editor
This paper presents simple sinusoidal PWM technique to reduced common mode voltage (CMV) at output terminal of the inverter. Multilevel inverter (MLI) is more suitable in high & medium power application, CMV is produced at the time of operation in output terminal of inverter. In this paper, an approach to reduced CMV at output terminal of MLI by using SPWM technique in three level diode clamped inverter (DCMLI) is proposed. A good transaction between the quality of the output voltage & the magnitude of CMV is achieved in this paper. The paper presents phase opposition & phase opposition disposition SPWM technique to reduced CMV in DCMLI. Simulation & experimental result presented to confirm the effectiveness of the proposed technique to control CMV.
1. The document discusses control strategies for EHV AC and DC transmission systems, including desired features of HVDC system control, control characteristics of constant current and constant extinction angle, and parallel operation of AC and DC systems.
2. Control of HVDC systems is achieved through control of current or voltage to maintain a constant voltage in the DC link. Common control modes include constant current control at the rectifier and constant extinction angle control at the inverter.
3. Parallel operation of AC and DC systems can present problems but also advantages; control coordination is needed between the two different transmission types.
A Three Level Single Stage PFC Converter for Variable Power Applicationspaperpublications3
Abstract: AC/DC power converters are required to operate with high power factor (PF) and low total harmonic distortion (THD) for improved grid quality and full capacity utilization of the transmission lines. Passive PF correction (PFC) circuits consist of inductive and capacitive filters followed by a diode bridge. They provide the simplest way of achieving high PF with high efficiency; however, they require low line frequency filters which are bulky and heavy. This work presents a new single stage three level isolated AC/DC PFC converter for high DC link voltage low-power applications achieved through an effective integration of AC/DC and DC/DC stages where all of the switches are shared between two operations. With the converter and switching scheme, input current shaping and output voltage regulation can be achieved simultaneously without introducing additional switches or switching actions. Due to the flexible DC link voltage structure, high power factor can be achieved at high line voltage. The performance of the single stage PFC converter is simulated in MATLAB/SIMULINK environment.
Keywords: Power Factor (PF), DC Link Voltage, Power Factor Correction Circuits (PFC).
Title: A Three Level Single Stage PFC Converter for Variable Power Applications
Author: Litty Joseph, Prof. Neetha John, Prof. Emmanuel Babu P
ISSN 2349-7815
International Journal of Recent Research in Electrical and Electronics Engineering (IJRREEE)
Paper Publications
Multi Carrier based Multilevel Inverter with Minimal Harmonic DistortionIJPEDS-IAES
This paper presents performance features of Asymmetric Cascaded
Multilevel inverter. Multilevel inverters are commonly modulated by using
multicarrier pulse width modulation (MCPWM) techniques such as phaseshifted
multicarrier modulation and level-shifted multicarrier modulation.
Amongst these, level-shifted multicarrier modulation technique produces the
best harmonic performance. This work studies about multilevel inverter with
unequal DC sources using level shifting MCPWM technique. The
Performances indices like Total Harmonic Distortion (THD), number of
switches and DC Sources are considered. A procedure to achieve an
appropriate level shifting is also presented is this paper.
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IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
High Power Density Multi-Mosfet-Based Series Resonant Inverter for Induction ...IAES-IJPEDS
Induction heating application uses uniquely high frequency series resonant
inverter for achieving high conversion efficiency. The proposed work focus
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MOSFET based series resonant inverter for the application of induction
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Keywords: Frequency Modulation, Resonant Converter, Zero Voltage Switching, Voltage Stress.
Title: Variable Switching Frequency Based Resonant Converter
Author: Anooja Shahul, Prof. Annie P Oommen, Prof. Sera Mathew
ISSN 2349-7815
International Journal of Recent Research in Electrical and Electronics Engineering (IJRREEE)
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voltage switching with SPWMis used for Inverter switching. In this paper, an in-depth analysis of unipolar
voltage switching technique with SPWM as applied to a single-phase full bridge Inverter is described and
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therefore eliminating the harmonic component from the Inverter output voltage resulting in a pure sinusoidal ac
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Control of Saturation level in the magnetic core of a welding transformer by Hysteresis Controller (HC) and Proportional Integral (PI) Controller
1. Rama Subbanna.S. Int. Journal of Engineering Research and Application www.ijera.com
ISSN : 2248-9622, Vol. 6, Issue 12, (Part -1) December 2016, pp.78-85
www.ijera.com 78 | P a g e
Control of Saturation level in the magnetic core of a welding
transformer by Hysteresis Controller (HC) and Proportional
Integral (PI) Controller
Rama Subbanna.S1
, Dr.M.Suryakalavathi2
ABSTRACT
The objective of this paper is to analyse the performances of two controllers such as Hysteresis control (HC)
and proportional integral (PI) control to control saturation level in the magnetic core of a welding transformer in
a middle-frequency direct current (MFDC) resistance spot welding system(RSWS). It consists of an input
converter, welding transformer, and a full-wave rectifier mounted at the transformer secondary. The unequal
ohmic resistances of the two transformer’s secondary circuits and the different characteristics of the diodes of
output rectifier certainly lead to the magnetic core saturation which, consequently, causes the unwanted spikes
in the transformer’s primary current and over-current protection switch-off. The goal is to analyse the
performance of both controllers in terms of transients, total harmonic distortion(THD) and variations in primary
current and flux in the magnetic core of a welding transformer of highly nonlinear system of RSWS. The
simulation study has been done in Matlab/Simulink environment and presented performance analysis. The
responses shows that from the aforementioned aspects, proportional integral Controller is the better choice for
controlling the saturation level in magnetic core of a welding transformer which is widely used in automobile
industry welding system.
Keywords: Magnetic core, core saturation, Hysteresis, Proportional Integral control, welding transformer.s
I. INTRODUCTION
Resistance spot welding is one of the most
widely used inexpensive and efficient material joining
processes in the automotive industry. This work deals
with the modeling, analysis and corresponding control
design of the welding current source, which represents
an electromagnetical subsystem of the entire welding
system. However, the technical questions of welding
itself are not a subject of this work.
Medium Frequency Direct Current (MFDC)
Resistance Spot Welding System (RSWS) is
extensively used in a large number of industries, such
as automotive, nuclear power, home appliances, as
well as civil infrastructure products. It has a great
many particular positive features in industrial
applications [1]. The working process of the
RSWS is a very complex one, which involves
interactions among electromagnetic, thermal,
mechanical, and metallurgical phenomena. Compared
to Alternative Current (AC) resistance spot welding
device, MFDC RSWS has a more complex structure
because it needs to generate a higher frequency than
that by its original power supply source. Generally
speaking, the working frequency of the MFDC RSWS
is about 1000Hz, while the frequency of the original
power supply is about 50/60Hz. Some necessary
transitions
from common electrical power to a low-voltage,
high-current and high-frequency electrical power
supply
should be accomplished. The complex structure and
working mechanism of the system may induce some
problems [2-4], such as magnetic saturation and
unwanted spikes in the currents. Klopcic [2-5]
analyzed the special electromagnetic structure and
proposed one method to deal with them. However, the
work focused on the magnetic saturation and the
mathematic model which the work used was
developed using electromagnetic features. Thus the
work concerned fewer about the variation of welding
current. In this paper, after studying the structure and
working principle of MFDC RSWS, different possible
operating modes of the system is found. The modes
can be described by how many diodes in two
secondary coils of welding transformer are switched
on. And then a new mathematical model is developed
to precisely describe the dynamic behavior of the
whole system.
When the current spikes are prevented
actively, closed-loop control of the welding current
and magnetic core flux density is required. Thus, the
welding current and the magnetic core flux density
must be measured. While the welding current is
normally measured by the Rogowski coil [10], the
magnetic core flux density can be measured by the
Hall sensor or by a probe coil wound around the
magnetic core. In the latter, the flux density value is
obtained by analogue integration of the voltage induce
in the probe coil [7]. Integration of the induced
RESEARCH ARTICLE OPEN ACCESS
2. Rama Subbanna.S. Int. Journal of Engineering Research and Application www.ijera.com
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voltage can be unreliable due to the unknown
integration constant in the form of remnant flux and
drift in analogue electronic components. The drift can
be kept under control by the use of closed-loop
compensated analogue integrator [9].
An advanced, two hysteresis controllers
based control of the RSWS, where current spikes are
prevented actively by the closed-loop control of the
welding current and flux density in the welding
transformer’s magnetic core, is presented in [9]. This
solution requires measuring of the welding current,
while instead of measured flux density only
information about magnetization level in the magnetic
core is required. Some methods tested on welding
transformer’s magnetic core, that can be applied for
magnetization level detection are presented in [7], [8].
All these methods require Hall sensor or probe coils
which make them less interesting for applications in
industrial RSWS, due to the relatively high sensitivity
on vibrations, mechanical stresses and high
temperatures. In order to overcome these problems, PI
controller is introduced. A dc-dc converter must
provide a regulated dc output voltage under varying
load and input voltage conditions. The converter
component values are also changing with time,
temperature, pressure, and so forth. Hence, the control
of the output voltage should be performed in a closed-
loop manner using principles of negative feedback.
The most common closed-loop control method for
PWM converter, namely, the current-mode control is
presented schematically in below section. The current-
mode control scheme is presented in section III. An
additional inner control loop feeds back an inductor
current signal, and this current signal, converted into
its voltage analog, is compared to the control voltage.
This modification of replacing the sawtooth waveform
of the voltage-mode control scheme by a converter
current signal significantly alters the dynamic
behavior of the converter, which then takes on some
characteristics of a current source. Among other
control methods of converters, a hysteretic (or bang-
bang) control is very simple for hardware
implementation. However, the hysteretic control
results in variable frequency operation of
semiconductor switches. Generally, a constant
switching frequency is preferred in power electronic
circuits for easier elimination of electromagnetic
interference and better utilization of magnetic
components So the constant switching frequency
gives better performance in the application of
resistance spot welding system (RSWS). It uses the
hysterisis controller. When it is used frequency cant
be maintained. And the transformer saturation also
happens due to the change in resistance of the RSWS.
In this paper, PI controller works well and
giving better performance in terms of limiting flux
density in order to limit the spikes in the primary
current caused by the saturation to prevent the over
current protection switch-off.
II. DYNAMIC MODEL OF THE RSWS
MFDC RSWS consists of an input rectifier, an H-
bridge inverter, a welding transformer with a full-
wave rectifier and corresponding load. A detailed
schematic presentation of MFDC RSWS is shown in
Fig. 1 [4]:
Fig.1.schematic representation of RSWS
The input rectifier is a three-phase full-wave
rectifier,
which can change the common three-phase
alternative
current (AC) voltage into a proper single-
phase current. The output welding current is
controlled by the voltage pulses generated through the
pulse width modulation (PWM) controller to drive the
H-bridge inverter. In above schematic presentation,
the AC voltages uu, uv, uw, which are provided from
the common electric grid, are rectified and smoothed
through the input rectifier in order to produce an
approximate direct voltage UDC. The square wave
voltage u, which is the voltage in the transformer’s
primary coil, is generated by the H-bridge inverter
which is composed of IGBT transistors S1 to S4 and
corresponding diodes DH1 to DH4.During working
process, the PWM controller is applied to generate
IGBT’ switching patterns for required input voltages
of the welding transformer. In other words, control of
the MFDC RSWS is the control of the status of the
IGBTs in real time. The welding transformer has one
primary coil (denoted by subscript 1 in Fig. 1) and
two secondary coils (denoted by subscripts 2 and 3 in
Fig. 1). N1, N2 and N3 are the number of turns, i1, i2 and
i3 are the currents in the coils, Lσ1, Lσ2 and Lσ3 are the
leakage inductances, while R1, R2 and R3 are the ohm
resistances of the corresponding transformer’s coils.
The welding transformer, which contains special
nonlinear magnetizing features, is represented by TR.
The iron core losses of TR are accounted for by the
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resistor RFe. The secondary coils of TR are connected
to output rectifier diodes D1 and D2. The resistor and
induction coil of the load are denoted by RL and LL.
The operation for the MFDC RSWS is to
regulate the welding current iL to a magnitude in
between the predetermined upper bound IMAX and
lower bound IMIN (a desired constant value is the best,
but this is impossible to achieve, thus a proper bound
is an alternative). At the same time, the magnetic flux
density (B) of the transformer’s iron core should be in
between its upper and lower magnetic saturation
bounds[4]: [-BM, BM]. This can be achieved by
changing the input voltage for the welding
transformer in three states: U, -U, and 0V, through
adjusting the patterns of IGBTs in the H-bridge
inverter by PWM controller.
The welding current (iL) is the sum of the
currents in the two secondary coils (Fig.1). A positive
input voltage (U) can actuate the top secondary coil;
while a negative input voltage (-U) can actuate the
bottom secondary coil. Hence, both of U and -U can
increase the load current. Only a zero input voltage
(0V) can decrease the load current. However, U and -
U can generate the opposite effect for variation of the
magnetic flux density (B). For example, if when U
increases the load current, but simultaneously B
reaches the bound, U must be changed into -U, which
can also increase the welding current, but B will
increase toward the opposite direction, which can
avoid the magnetic saturation.
When opposite input voltage is provided, the
energy
which is stored by inductance coil in original
circuit will decrease; while that in the other circuit
will increase. And when the welding current should
be decreased and a zero voltage is provided, the
inductor coil will substitute the power source and a
new back circuit will form. Thus in a certain period,
both of the two diodes in the secondary coils are
switched on at the same time because the inductor
coils can suspend the transformation. And this
phenomenon can appear when the pattern of input
voltage changes between its three states (U,-U and
0V) because of the same reason. Normally, it is
impossible for the two diodes to be switched off at the
same time, unless the welding process is over.
The dynamic model of the RSWS was built
based on the schematic presentation, shown in Fig.1.
In this work the model is built with the programme
package Matlab/Simulink based on the following set
of equations (1) – (9).
uH = R1i1+Lσ1(di1/dt)+ N1(dφ /dt) (1)
0 = R2i2+Lσ2(di2/dt)+ N2(dφ/dt) + dip1+ RLiL+LL(d(i2+
i3)/dt) (2)
0 = R3i3+Lσ3(di3/dt)-N3(dφ /dt) + dip2+ RLiL+LL(d(i2+
i3)/dt) (3)
N1ip+N2i2- N3i3=H(B)lic+2δB/μ0 (4)
iL = i2+ i3 (5)
i1 = iFe+ ip (6)
The results of simulations, obtained by the dynamic
model of the RSWS, show that small difference in
resistances R2, R3 and in characteristics of the
rectifier diodes D1 and D2 can cause unbalanced time
behavior of the magnetic core flux and the current
spikes in the primary current i1, shown in Fig.2. The
a) and b) graphs in Fig. 2 show the same variables in
different time scales. The current spikes appear
approximately after 0.06s (Fig.2(c)). After 0.07s the
current spikes become high enough to cause the over-
current protection switch off of the RSWS.
(a)
(b)
(c)
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(d)
Fig.2. (a),(b)and (c) : Time behaviour Primary
Current i1 (d) FluxDensity
III. CONTROLLER DESIGN
The current spikes in transformer primary
current are the direct consequence of transformer iron
core saturation caused by the offset of flux density
(Figs. 3 and 5). The basic idea on how to eliminate
these current spikes is, therefore, the design of
advanced control, which will closed-loop control
both, saturation level in the transformer iron core and
the welding current.
A dc-dc converter must provide a regulated
dc output voltage under varying load and input
voltage conditions. The converter component values
are also changing with time, temperature, pressure,
and so forth. Hence, the control of the output voltage
should be performed in a closed-loop manner using
principles of negative feedback. The most common
closed-loop control method for PWM converters,
namely, the current-mode control, are presented
schematically in Fig.5.
I. Hysteresis Controller :
Reference currents are generated by DC to
AC converters using a current control technique such
as a hysteresis control. The hysteresis band is used to
control load currents and determine switching signals
for inverters gates, George & Agarwal (2007) Suitable
stability, fast response, high accuracy, simple
operation, inherent current peak limitation and load
parameters variation independency make the
hysteresis current control as one of the best current
control methods of voltage source inverters. In this
approach the current error, (difference between the
reference and inverter currents) is controlled in
hypothetical control band surrounding reference
current.
When the load current exceeds the upper
band, the comparator output activated so the output
voltage is changed in such a way to decrease the load
current and keep it between the bands and deactivated
at lower limit. Switching frequency varies with
respect to distance between upper and lower band.
The other parameters like inverter-network inductance
and DC link voltage affect significantly on the
switching frequency. inverter can be controlled in
unipolar or bipolar PWM method. In this approach the
current error, (difference between the reference and
inverter currents) is controlled in hypothetical control
band surrounding reference current as shown in
Figure 3.
Fig.3 : Basic concept of Hysteresis Control
In hysteresis current control based on
unipolar PWM, there are two upper bands and lower
bands in order to change the slop of inverter output
current based on their level voltages, +Vo, 0 and -Vo.
The idea is to keep the current within the main area
but the second upper and lower bands are to change
the voltage level in order to increase or decrease the
di,/dt of inverter output current.
Fig.4 : Noisy Load Current with lower and upper
bands.
ΔI cannot be very small as the noisy signal
changes the switching time due to instantaneous
comparison between the load and the reference
currents and increases the switching losses and it
cannot be big as the total harmonic distortion may be
increased.In APF, load current has several different
slopes within one cycle and to have a fast current
tracking, the control algorithm in unipolar current
control has been defined based on magnitude and time
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errors control as shown in Figure 3 (b). In this case,
the second upper or lower band values can be big
enough in order to remove the noise issue of the
inverter output current but the second decision to
change the level is based on time error. For example,
when the load current exceeds the first upper band at
t4, the output voltage of inverter is change from +Vo
to 0. The controller waits for Δt, if the inverter output
current does not cross the second upper band within
this period, thenthe controller changes the output
voltage from zero to –Vo at t5. In this case, when the
slope of reference current is close to the slop of
inverter output current, then the time error control
improves the quality of the APF and pushes the
inverter current into the main area. It is proven that
the current control based on unipolar PWM has a low
switching losses or better performance compare to the
other methods of control techniques. The load and
compensated currents THD(total harmonics
distortions) can be reduced sufficiently by using
hysteresis current control based unipolar PWM.
(b) PI Controller
In control engineering, a PI Controller
(proportional-integral controller) is a feedback
controller which drives the plant to be controlled with
a weighted sum of the error (difference between the
output and desired set-point) and the integral of that
value. PI controllers consist of a proportional gain that
produces an output proportional to the input error and
an integration to make the study state error zero for a
step change in the input.
The controller output is given by
(1)
where Δ is the error or deviation of actual measured
value (PV) from the set-point (SP).
Δ=SP-PV. (2)
A PI controller can be modelled easily in software
such as Simulink using a "flow chart" box involving
Laplace operators:
(3)
Where,G = KP = proportional gain and G / τ = KI =
integral gain.
Setting a value for G is often a tradeoff between
decreasing overshoot and increasing settling time. The
integral term in a PI controller causes the steady-state
error to reduce to zero, which is not the case for
proportional only control in general.
The current-mode control scheme is presented in
Fig.1 An additional inner control loop feeds back an
inductor current signal, and this current signal,
converted into its voltage analog, is compared to the
control voltage. This modification of replacing the
sawtooth waveform of the voltage-mode control
scheme by a converter current signal significantly
alters the dynamic behavior of the converter, which
then takes on some characteristics of a current source.
Fig. 5: Current mode control of PI control
The current-mode control scheme is
presented in Fig.5(b) An additional inner control loop
feeds back an inductor current signal, and this current
signal, converted into its voltage analog, is compared
to the control voltage. This modification of replacing
the sawtooth waveform of the voltage-mode control
scheme by a converter current signal significantly
alters the dynamic behavior of the converter, which
then takes on some characteristics of a current source.
The output current in PWM converters is either equal
to the average value of the output inductor current or
is a product of an average inductor current and a
function of the duty ratio. In practical
implementations of the current-mode control, it is
feasible to sense the peak inductor current instead of
the average value. As the peak inductor current is
equal to the peak switch current, the latter can be used
in the inner loop, which often simplifies the current
sensor. Note that the peak inductor (switch) current is
proportional to the input voltage. Hence, the inner
loop of the current-mode control naturally
accomplishes the input voltage-feed forward
technique. Among several current-mode control
versions, the most popular is the constant-frequency
one that requires a clock signal. Advantages of the
current- mode control are the input voltage feed
forward, the limit on the peak switch current, the
equal current sharing in modular converters, and the
reduction in the converter dynamic order. The main
disadvantage of the current-mode control is its
complicated hardware, which includes a need to
compensate the control voltage by ramp signals (to
avoid converter instability).Among other control
methods of converters, a hysteretic (or bang-bang)
control is very simple for hardware implementation.
However the hysteresis control results in variable
frequency operation of semiconductor switches.
Generally a constant switching frequency in power
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electronic circuits for easier elimination of
electromagnetic interference and better utilization of
magnetic components.
IV RESULTS AND DISCUSSION
Simulation results of Hysteesis and PI
controllers are presented here. primary current and
fluxdensity of both controlleres are shown in fig.6.(a)
and (b). In fig.6(a), primary current of a welding
transformer can
be seen spikes in a time scale of 0.08 to 0.09 sec.
Since the hysteresis controller is not able to maintain
the flux density with in the preset values (i.e., -1T to
1T) this spikes are not eliminated successfully. For
the time scale, this spikes are completly eliminated by
maintaining the flux density with in the preset values
as -1T to 1T with PI controller can be seen in
fig.6.(b). Total Harmonic Distortion (THD) variation
can be seen in fig.7.(a) and (b). THD of HC is 60.81%
and PI is 37.32%. PI gives better performance than
the HC from the aformentioned aspects.
(a)
(b)
Fig.6. (a) and (b): combined Primary current and FluxDensity of HC and PI control
(a)
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(b)
Fig.7. (a) and (b): THD of HC and PI Control
V CONCLUSION
In this paper, two controllers such as
Hysteresis and PI are successfully designed. Based on
the simulation results and the analysis, a conclusion
has been made that PI control having less
THD(37.32%) than Hysteresis control(60.81%). PI
controller is capable of controlling the saturation level
in the magnetic core of a welding transformer of
nonlinear RSWS system
Flux Density can be maintained with in a preset
values successfully in order to eliminate the spikes in
the primary current of a welding transformer.
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8. Rama Subbanna.S. Int. Journal of Engineering Research and Application www.ijera.com
ISSN : 2248-9622, Vol. 6, Issue 12, (Part -1) December 2016, pp.78-85
www.ijera.com 85 | P a g e
Rama Subbanna, S. graduated from Jawaharlal Nehru Technological University in the year 2003. M.Tech
from Jawaharlal Nehru Technological University, Hyderabad, in the year 2006. Currently, He
is pursuing Ph.D from Jawaharlal Nehru Technological University, Anantapur, India. His
research includes Power Systems, Magnetic Materials, Controllers, Artificial Intelligence
Techniques
Dr.Suryakalavathi, M. graduated from S.V.University, Tirupati in the year 1988. M.Tech from S.V.University,
Tirupati in the year 1992. Ph.D from J.N.T.University, Hyderabad in the year 2006 and Post
Doctoral from CMU, USA. She is presently professor of Electrical and Electronics
Engineering department, J.N.T.U.College of Engineering, Hyderabad. She presented more
than 70 research papers in various national and international conferences and Journals. Her
research area includes High Voltage Engineering, Power Systems and Artificial Intelligence
Methods.