This document summarizes a student's major assignment on designing a controller for a buck-boost converter circuit. The student developed mathematical models to describe the circuit and analyze power losses. Based on this, the student designed a controller using a combined feedback and feedforward approach to minimize losses while maintaining output voltage and rejecting disturbances. Simulation results showed the controller could successfully drive the circuit in both buck and boost modes and regulate the output voltage even for non-linearized steady states.
A high efficiency non isolated buck-boost converter based on zeta converterAsoka Technologies
In this paper, a new transformerless buck-boost converter based on ZETA converter is introduced. The proposed converter has the ZETA converter advantages such as, buck-boost capability, input to output DC insulation and continuous output current. The suggested converter voltage gain is higher than the classic ZETA converter. In the presented converter, only one main switch is utilized. The proposed converter offers low voltage stress of the switch; therefore, the low on-state resistance of the main switch can be selected to decrease losses of the switch. The presented converter topology is simple; hence, the control of the converter is simple. The converter has the continuous output current. The mathematical analyses of the presented converter are given. The experimental results confirm the correctness of the analysis.
Design and analysis of boost converter with cld celleSAT Journals
Abstract
In this paper, the output voltage in renewable energy sources is improved by using DC-DC converter topology. Basically Boost
converter is used for improving the voltage gain. In this converter switching frequency is limited, hence the output voltage is
reduced. To overcome this issue, by using the boost converter with CLD cell is proposed .In this proposed paper for comparing
the voltage stress and efficiency by using two converters topology. For the duty ratio of 0.5 the output voltage is compared with
the conventional boost converter.
Keywords- Boost Converter, Boost Converter with CLD, Voltage Stress
A high efficiency non isolated buck-boost converter based on zeta converterAsoka Technologies
In this paper, a new transformerless buck-boost converter based on ZETA converter is introduced. The proposed converter has the ZETA converter advantages such as, buck-boost capability, input to output DC insulation and continuous output current. The suggested converter voltage gain is higher than the classic ZETA converter. In the presented converter, only one main switch is utilized. The proposed converter offers low voltage stress of the switch; therefore, the low on-state resistance of the main switch can be selected to decrease losses of the switch. The presented converter topology is simple; hence, the control of the converter is simple. The converter has the continuous output current. The mathematical analyses of the presented converter are given. The experimental results confirm the correctness of the analysis.
Design and analysis of boost converter with cld celleSAT Journals
Abstract
In this paper, the output voltage in renewable energy sources is improved by using DC-DC converter topology. Basically Boost
converter is used for improving the voltage gain. In this converter switching frequency is limited, hence the output voltage is
reduced. To overcome this issue, by using the boost converter with CLD cell is proposed .In this proposed paper for comparing
the voltage stress and efficiency by using two converters topology. For the duty ratio of 0.5 the output voltage is compared with
the conventional boost converter.
Keywords- Boost Converter, Boost Converter with CLD, Voltage Stress
Abstract This paper deals with the operation of the separately excited dc-drive in each of the four quadrants which is fed by symmetrical multi pulse modulated signal, leads to improved power quality by using single-phase, dual AC-DC buck converter. Here the armature control of the dc drive with constant load torque is considered in both forward and reverse directions in the motoring and generating actions. When a variable load condition occur the load voltage get changed, simultaneously other parameters such as torque, speed at load side and voltage, current profiles at source side get affected. Due to which there is lot of distortion in the sending end parameters. To overcome these drawbacks the essential variables are analyzed by feeding these variables back to the converter switches, which regulates the output voltage, fed to separately excited DC-Drive, which indicates that, at the ac interface the harmonic profile of the separately excited dc drive fed by the improved power quality dual converter is achieved using closed loop system. Keywords: AC-DC Buck Converter, Power Quality, Closed Loop, PI Controller, Symmetrical Multipulse Modulation (SMM) etc.
Brushless DC motor is a synchronous machine that makes use of electronic commutation instead of mechanical commutator. Brushless DC motors makes use of inverter encompassing static switches for its operation. A simple bridge converter when used for BLDC drive as front end converter makes input source power factor to get reduced which is unacceptable in the power system. To avoid the distortions in the source voltage and source currents, Buck converter which was used as power factor correction (PFC) converter in this paper to improve the power factor. Presence of power electronic converters deteriorates system power factor effecting overall system performance. This paper presents buck converter for power factor correction in brushless DC motor drive system. Buck converter is operated with current control strategy rather to conventional voltage follower control. Simulation model was obtained using MATLAB/SIMULINK software and the brushless DC motor performance characteristics were shown for conditions with different DC link voltages and step variation in DC link voltage. Total harmonic distortion in source current was also presented.
Abstract This paper deals with the operation of the separately excited dc-drive in each of the four quadrants which is fed by symmetrical multi pulse modulated signal, leads to improved power quality by using single-phase, dual AC-DC buck converter. Here the armature control of the dc drive with constant load torque is considered in both forward and reverse directions in the motoring and generating actions. When a variable load condition occur the load voltage get changed, simultaneously other parameters such as torque, speed at load side and voltage, current profiles at source side get affected. Due to which there is lot of distortion in the sending end parameters. To overcome these drawbacks the essential variables are analyzed by feeding these variables back to the converter switches, which regulates the output voltage, fed to separately excited DC-Drive, which indicates that, at the ac interface the harmonic profile of the separately excited dc drive fed by the improved power quality dual converter is achieved using closed loop system. Keywords: AC-DC Buck Converter, Power Quality, Closed Loop, PI Controller, Symmetrical Multipulse Modulation (SMM) etc.
Brushless DC motor is a synchronous machine that makes use of electronic commutation instead of mechanical commutator. Brushless DC motors makes use of inverter encompassing static switches for its operation. A simple bridge converter when used for BLDC drive as front end converter makes input source power factor to get reduced which is unacceptable in the power system. To avoid the distortions in the source voltage and source currents, Buck converter which was used as power factor correction (PFC) converter in this paper to improve the power factor. Presence of power electronic converters deteriorates system power factor effecting overall system performance. This paper presents buck converter for power factor correction in brushless DC motor drive system. Buck converter is operated with current control strategy rather to conventional voltage follower control. Simulation model was obtained using MATLAB/SIMULINK software and the brushless DC motor performance characteristics were shown for conditions with different DC link voltages and step variation in DC link voltage. Total harmonic distortion in source current was also presented.
Performance comparison of different control strategies for the regulation of ...IJECEIAES
In last years, DC-DC converters solve the most issues in the industrial application in the area of power electronics, especially renewable energy, military applications and affiliated engineering developments. They are used to convert the DC input that unregulated to regulated output perhaps larger or smaller than input according to the type of converters. This paper presents three primary control method used for negative output Super lift Luo DC-DC converter. These methods include a voltage mode control (VMC), current mode control (CMC), and Sliding mode control (SMC). The goal of this article is to study and selected an appropriate and superior control scheme for negative DC-DC converters. The simulation results show the effectiveness of Sliding mode control for enhancing the performance of the negative DC-DC converter. Also, this method can keep the output voltage constant under load conditions. Simulation results obtained by the MATLAB/Simulink environment.
Bus ele tech_lib_short_circuit_current_calculations (1)ingcortez
LIBRO DE CALCULOS DE DATOS DE CORTO CIRCUITO ELÉCTRICO PARA CONDUCTORES DE COBRE Y ALUMINIO DEL TIPO MONOPOLARES O TRIFASICOS DENTRO DE CANALIZACIONES ELECTRICAS PLASTICAS O METALICAS EN VOLTAJES DE MEDIA Y BAJA TENSION CON FACTORES O CONSTANTES DE LOS CONDUCTORES ELECTRICOS EN METROS
Voltage profile Improvement Using Static Synchronous Compensator STATCOMINFOGAIN PUBLICATION
Static synchronous compensator (STATCOM) is a regulating device used in AC transmission systems as a source or a sink of reactive power. The most widely utilization of the STATCOM is in enhancing the voltage stability of the transmission line. A voltage regulator is a FACTs device used to adjust the voltage disturbance by injecting a controllable voltage into the system. This paper implement Nruro-Fuzzy controller to control the STATCOM to improve the voltage profile of the power network. The controller has been simulated for some kinds of disturbances and the results show improvements in voltage profile of the system. The performance of STATCOM with its controller was very close within 98% of the nominal value of the busbar voltage.
Enhancement of Power System Dynamics Using a Novel Series Compensation SchemeIJMER
Phase imbalanced capacitive compensation is a “hybrid” series compensation scheme, where the
series capacitive compensation in one phase is created using a single-phase TCSC in series with a fixed capacitor
(Cc), and the other two phases are compensated by fixed series capacitors (C). The TCSC control is initially set
such that its equivalent compensations at the power frequency combined with the fixed capacitor yield a
resultant compensation equal to the other two phases. Thus, the phase balance is maintained at the power
frequency while at any other frequency, a phase imbalance is created. The effectiveness of the scheme in damping
power system oscillations for various network conditions, namely different system faults and tie-line power flows is
evaluated using the MATLAB/SIMULINK Software
Aircraft Electrical Power Generation & Distribution System Units Through an A...IJMTST Journal
This paper illustrates a generic Electrical Power Generation & Distribution System. The AC power frequency is variable and depends of the engine speed. The represents the generator mechanical drive and is modeled by a simple signal builder, which provides the mechanical speed of the engine shaft.The represents the power AC generator. It is composed of a modified version of the simplified synchronous machine. The mechanical input of the modified machine of 50 kW is the engine speed. The Generator Control Unit regulates the voltage of the generator to 200 volts line to line.The represents the Primary Distribution system. It is composed of three current and voltage sensors. There is also a 3-phase contactor controlled by the Generator Control Unit. Finally, a parasitic resistive load is required to avoid numerical oscillations. The section represents the secondary Power Distribution system. It is represented by 4 circuit breakers with adjustable current trip. The section represents the AC loads. There is a 4 kW Transformer and Rectifier Unit (which supplies 28 Vdc), a 12 kW induction machine (motor driving a pump), a 1 kW resistive load (lamps) and a 3 hp simplified (using an average value inverter) brushless DC drive (motor driving a ballscrew actuator)
This paper proposes the grid application of modified three-phase topology of Modular Multilevel Converter (MMC) using finite-control-set predictive control. This topology has reduced number of switch counts compared to the conventional MMC, eliminates the problem of circulating current and having higher efficiency. A single dc source is required to produce sinusoidal outputs. The number of sub-modules (SMs) in this topology is half of the SMs required in case of MMC, in addition to a single H-bride circuit per phase. The finite-control-set predictive current control scheme for the grid connected dc source through the Hybrid Modular Multilevel Converter (HMMC). This controller controls the desired real and reactive power demand of the grid instantaneously. The simulation study of a three phase grid connected system has been done in Matlab/Simulink and the results are provided for the different real and reactive power demands, to validate the concepts.
ENHANCING RELIABILITY BY RECONFIGURATION OF POWER DISTRIBUTION SYSTEMS CONSID...Suganthi Thangaraj
The paper describes an effective method to reconfigure a power distribution system using optimization techniques. Here genetic algorithm is used for the reconfiguration to enhance reliability and to reduce losses. The reliability at the load points is evaluated using probabilistic reliability approach. For finding minimal cut sets and losses different algorithms are used. To maximise the reliability and to reduce the losses, the status of the switch is controlled using genetic algorithm. The effectiveness of the system is tested in 33 bus distribution system.
Voltage profile Improvement Using Static Synchronous Compensator STATCOMINFOGAIN PUBLICATION
Static synchronous compensator (STATCOM) is a regulating device used in AC transmission systems as a source or a sink of reactive power. The most widely utilization of the STATCOM is in enhancing the voltage stability of the transmission line. A voltage regulator is a FACTs device used to adjust the voltage disturbance by injecting a controllable voltage into the system. This paper implement Nruro-Fuzzy controller to control the STATCOM to improve the voltage profile of the power network. The controller has been simulated for some kinds of disturbances and the results show improvements in voltage profile of the system. The performance of STATCOM with its controller was very close within 98% of the nominal value of the busbar voltage.
In the modern power system the reactive power compensation is one of the main issues, the transmission of active power requires a difference in angular phase between voltages at the sending and receiving points (which is feasible within wide limits), whereas the transmission of reactive power requires a difference in magnitude of these same voltages (which is feasible only within very narrow limits). The reactive power is consumed not only by most of the network elements, but also by most of the consumer loads, so it must be supplied somewhere. If we can't transmit it very easily, then it ought to be generated where it is needed." (Reference Edited by T. J. E. Miller, Forward Page ix).Thus we need to work on the efficient methods by which VAR compensation can be applied easily and we can optimize the modern power system. VAR control technique can provides appropriate placement of compensation devices by which a desirable voltage profile can be achieved and at the same time minimizing the power losses in the system. This report discusses the transmission line requirements for reactive power compensation. In this report thyristor switched capacitor is explained which is a static VAR compensator used for reactive power management in electrical systems.
Seminar Topic For Electrical and Electronics Engineering (EEE)
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Emc model for modern power electronic systems for harmonics, losses & emi...eSAT Journals
Abstract
Electromagnetic compatibility of power electronic systems becomes an engineering discipline and it should be considered at the
beginning stage of a design. Thus, a power electronics design becomes more complex and challenging and it requires a good
communication between EMI and Power electronics experts. Three major issues in designing a power electronic system are Losses,
EMI and Harmonics. These issues affect system cost, size, efficiency and quality and it is a tradeoff between these factors when we
design a power converter, filter. In this paper the EMC model is discussed which should be considered while designing the power
electronics systems. The design considerations in this paper help us to remove losses, harmonics & EMI elimination and power
quality improvement of Power systems.
Index Terms: Converter, EMI, EMC, Filter, Harmonics
An Improved Repetitive Control for Circulating Current Restraining in MMC-MTDCTELKOMNIKA JOURNAL
The modular multilevel converter (MMC) is widely used in many important application fields such
as high voltage DC transmission system. And the multi-terminal architecture of it attracts many attentions.
However, the circulating current of MMC is an inherent problem which is mainly caused by the voltage
mismatch between arms and DC bus. In this paper, an advanced repetitive control method is proposed.
This method is based on the even-harmonic characteristic of the circulating current and the potential
feature of repetitive control that it has an internal integration part. The pole diagram of the closed loop
transform function of the proposed control system proves the stability of the proposed method. And
according to the simulation results of a three-terminal MMC-MTDC model in PSCAD/EMTDC, the
improved repetitive control presents better circulation repression ability and superior anti-interference
capability by comparing with traditional PI control method. Additionally, the simulation results also indicate
that the proposed repetitive controller can restrain the fluctuation of SM voltage more effectively than PI
control.
Connector Corner: Automate dynamic content and events by pushing a buttonDianaGray10
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Send an interactive Slack channel message (using buttons)
Have the message received by managers and peers along with a test email for review
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In a second workflow supporting the same use case, you’ll see:
Your campaign sent to target colleagues for approval
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But—if the “Reject” button is pushed, colleagues will be alerted via Slack message
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Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
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Report buck boost k10972
1. MAJOR ASSIGNMENT
Buck Boost Converter
SECTION: G-2 (MECHANICAL ENGG.)
CAREER POINT UNIVERSITY
KOTA, RAJASTHAN
Prepared by Prepared for
Vinit Kumar Chauhan Mr.Somesh Sir
Course: B.Tech(6th
sem.)
UID: K10972
2. ABSTRACT
A study on the properties and control of a promising circuit topology for a DC-DC
buckboost power converter is presented. The circuit contains four transistors
operated synchronously in couples. We propose a set of mathematical models to
describe this circuit, and an approach to determine the behavior of the losses
occurring inside of it. These are then combined in order to achieve a control
scheme that drives the circuit while minimizing said losses. The control strategy
proposed here is based on a combined feedback (MPC) and feedforward action.
Control performance parameters such as disturbances rejection capability have
been investigated as well.
INTRODUCTION
once provided by the diode - i.e. current rectification - is now undertaken by a
rectifying transistor, typically a MOSFET. Such rectification improves efficiency,
thermal performance, power densities, manufacturability, reliability as well as
having typically faster switching transients, and decreases the overall system cost
for power supplies (Selders 2003). These performance increases are mainly due to
the fact that the on-resistance of MOSFETs, RDS;on, can be reduced either by
increasing the size of the die or by paralleling discrete devices, while the forward
voltage-drop across diodes cannot be lowered under a certain (physically imposed)
limit; this motivates the choice of using synchronous rectifiers in the circuit
topology studied for this project.
The main objective of this project can now be stated as follows: by exploiting
these two degrees of freedom we will be able to affect the state of the circuit;
thus, many internal states will lead to the same output voltage, and the main task
will be to choose among all these possibilities the one that will lead to the least
possible power losses - i.e. to the most efficient way of driving the circuit.
This has been achieved as follows: first, different models of the circuit have been
developed for different purposes, see next Chapter. After that, a thorough study of
the losses inside the circuit has been conducted using some of these models. Based
on the study of the losses, the design of a control that drives the circuit while
accounting for losses has been done, and conclusive chapter, where possible
outlooks will be discussed and a summary of this project will be given.
3. Basic Analytical Models: Full-Buck
The circuit can be considered equivalent to a synchronous buck converter if the
third switch T3 is always turned on, i.e. if d2 = 1. Apreliminary study of the ”buck
mode” is useful to show the general approach which is going to be used for more
complex modes.
It turns out in fact that this version is the most attractive one as a starting point
for a study because the differential equations describing the states of the circuit
coming from the averaging method are linear by nature. This makes the successive
development of a control for this mode of the circuit straight-forward.
The procedure is the following: first, consider the case where T1 is on, and T2 is
off; applying Kirchhoff Voltage Law (KVL) and Kirchhoff Current Law (KCL) to
the circuit depicted in Figure 2.1 leads to the following equations for the states:
Then, consider the complementary case where T1 is off, and T2 is on; the same
equations hold basically, if vin is taken to be zero. Again, applying KCL and KVL
leads to:
4. Power Losses
Our objective is to drive the circuit while minimizing the losses occurring inside
of it. In order to do this, models for the behavior of these losses are necessary;
Losses Description
There are two different types of losses occurring inside the circuit: Conduction
Losses (PConduction) and Switching Losses (PSwitching); in the following, these
two types of losses are going to be shortly described.
Conduction Losses
These are losses of resistive type, and, for the particular circuit that is investigated,
they are produced because of current flowing through the following resistive
media:
MOSFETs’ channel resistance RDS;on
MOSFETs’ body diode
Capacitance’s ESR (Equivalent Series Resistance)
Inductance’s ESR
Switching Losses
The mechanisms involved in the production of switching losses are more
complicated than the previous ones. They are produced by the action of turning on
and off active devices on the power’s path, therefore they only happen at discrete
times ”tj” (where j indexes all the times at which switchings of a given MOSFET
occur) and for a short period; they occur under the following circumstances
(Mohanet al. n.d.):
switching of power currents (”turning on and off currents in the presence of
voltage”)
parasitic drain capacitance charge and discharge
gate drive losses
body diode reverse recovery
5. MODELING POWER LOSSES
because of this, if the current iL is positive (flowing from the input stage to the
output stage), then switching losses will occur only at switches T1 and T4.
Conversely, if iL is negative, then switching losses will occur in switches T2 and
T3. On a side note, it can be noted that since these losses occur at switching times,
the more switchings there are, the higher the switching losses will be (if the same
MOSFETs are used), i.e. switching losses grow proportionally to the switching
frequency.
Therefore, on one hand, switching frequency should not be chosen to be arbitrarily
high. But on the other hand, switching frequency should not be chosen too low
either because that would cause higher ripples on the output voltage.
Also, it is of critical importance to note at this point that during the simulations
described further in this chapter, the magnitude of the losses is estimated using
these very equations. But since these equations only give results that are
proportional to the exact values, their shape will describe the general behavior of
the losses properly, but their magnitude will need to be corrected by an adequate
multiplicative correction constant. This constant will strongly depend on the choice
of components that is going to be made. This aspect is discussed more in detail in
the next Section.
Controller Design
Based on the research done on the models in Chapter 2 and the Losses in Chapter3,
it is now possible to start developing an efficient control for the plant. As a
reminder, our task is to control the duty cycles of each pair of transistors and their
phase, so as to ensure:
First and most important: reaching of and stabilizing around a given output
voltage demand;
reaching the target steady state should happen in the desired manner, i.e.
The controller needs to handle transients properly;
The controller also needs to be able to reject disturbances (usually
encountered on the load and on the input voltage source vin);
while doing all this, the controller (in the full buck-boost mode) needs to
choose among the infinite possibilities of inputs, that would satisfy the
above conditions, those that will cause the least losses.
6. Basic Control Strategies
Buck, the Simplest Mode
As discussed in Chapter 2.3.1, the model obtained with the averaging technique
is linear. There is only one variable being controlled (d1) and there is no
optimization of controls towards least losses. This is why a simple feedback
approach (as opposed to a combined feedforward and feedback approach, as
discussed later) is enough to control this scheme.
Buck-Boost Operation
The buck-boost implementation is similar to the boost one in that non-linearity is
still present. Other than that, it turns out that exploiting the possibilities given by
the full buck-boost operation requires additional care because:
There are now multiple inputs
Control actions also need to drive the plant while ensuring least possible
losses
Results
It can be argued that if this precalculated lookup table does indeed contain the best
values the plant (circuit) can be driven at steady state, then the contribution from
the MPC feedback can be avoided. This is of course not the case: first, it is clear
that the contribution from the MPC boosts the performance during the initial
transient. Furthermore, a feedback action is always desired in any control scheme,
in order to ensure the ability to reject disturbances and model uncertainties.
The two contributions to the u signal coming from the feedback and from the
feedfoward part can be seen in Figure 4.10. As it can be seen, the MPC supplies
the plant with a contribution different than zero only during the transient. As soon
as the transient has settled, it contribution goes to zero and stays there; this is
always the case as long as no disturbances or other external influences affect the
circuit; if disturbances are indeed applied, then the MPC control is going to counter
those and its contribution is going to be different than zero.
A typical disturbance rejection done by the controller can be seen in the blue
bottom curve depicts the perturbation (in percentage) affecting the input voltage
vin, while in the upper graph, the red curve shows how this perturbation affects the
output voltage if no feedback action is taken, and the green one shows the output if
rejections are countered by the MPC.
7. The resulting output start-up performance for a set of different output references
can be seen in notice that the controller is indeed able to drive the circuit both in its
”buck” mode and ”boost” mode, as specified in the objectives for this project.
Further, notice that the control is indeed able to properly drive the plant also
towards steady states different than those around which the models were
linearized, thus showing its ”well” behavior.
Conclusion
The present work is a study on the circuit depicted in Figure 1.2 which is used to
achieve DC-DC power conversion. In the first part of the work (Chapters 1-3),
different models for its behavior have been developed, including a state-space
averaged model and an hybrid one.
Based on these models simulations have been conducted in order to assess the
losses occurring inside of it. These simulations reveal that it is in general not
possible to drive the circuit while minimizing simultaneously both conduction and
switching losses. Rather, in order to drive the circuit in the most efficent way, an
optimizedbalance between these two losses needs to be made. Further, this balance
depends on the specific choice of components used.
In the second part of the work (Chapter 4), for a specific choice of components,
the implementation of a controller for this circuit is discussed. The controller has
been designed as working on the combined action of a precalculated look-up table
(feedforward action) and a Model Predictive Control (MPC) based feedback
action.
The abilty to drive the circuit both in its boost as well its buck modes and its noise
rejection capabilty are the performance benchmarks for this controller which have
been studied. Recommended extensions to this work include the refinement of the
models to account for parasitics and non-ideal behaviours, so as to enable a
subsequent controller implementation based solely on MPC, and a more accurate
evaluation of thecontroller’s stabilization capabilties.
Bibliography
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