1) Synchronverters are inverters that mimic the behavior of synchronous generators through control algorithms. They can help address challenges from increasing distributed renewable generation connected to the grid.
2) A synchronverter model is presented that electrically and mechanically mimics the behavior of a synchronous generator. The electrical model includes flux linkages and back EMF equations. The mechanical model includes inertia and torque equations.
3) The implementation of a synchronverter consists of an electronic part that generates the back EMF signal and a power part with an inverter and filter. The electronic and power parts interact through current feedback and PWM control to generate voltages matching the back EMF.
The document describes a project to design a microgrid using synchronverters. It discusses the challenges of instability in grids and proposes using synchronverters to control inverters like synchronous machines for stability. The project involves modeling synchronverters for a grid, wind farm, solar farm, and battery storage. Controllers are developed using synchronous machine models and droop functions. Simulations are conducted in MATLAB to test synchronization using PLL and self-synchronization, operation in set and droop modes, and response to load changes. Experimental results from the simulations demonstrate the synchronverters' frequency response and P-Q outputs in different operating conditions.
Lecture Outline
Introduction to subject
Application Areas
Power Electronic Devices
Power Converters
What is power electronics?
1) Definition
Power Electronics: is the electronics applied to conversion and control of electric power.
Prerequisites
Power electronics incorporates concepts from the fields of
Analog circuits
Electronic devices
Control systems
Power systems
Magnetics
Electric machines
Numerical simulation
Scope
It is not possible to build practical computers, cell phones, personal data devices, cars, airplanes, industrial processes, and other everyday products without power electronics.
Alternative energy systems such as wind generators, solar power, fuel cells, and others require power electronics to function.
Technology advances such as electric and hybrid vehicles, laptop computers, microwave ovens, flat-panel displays, LED lighting, and hundreds of other innovations were not possible until advances in power electronics enabled their implementation.
Although no one can predict the future, it is certain that power electronics will be at the heart of fundamental energy innovations.
Applications: Electric VehicleTesla Model S
Functions of the power electronics:
1. Convert the DC battery voltage to the variable AC required to drive the AC motor
240 V battery
Variable-frequency, variable-voltage AC drives the motor
AC motor propels the rear axle
Up to 330 kW (acceleration)
Up to 60 kW regenerative braking
2. Control charging of the battery
Interface to 240 V 60 Hz 1φ 100 A circuit in garage.
Control AC current waveform to be sinusoidal, unity power factor.
Control charging of battery to maximize life.
Applications: Hybrid VehiclesPrius
Power Electronics Module:
Convert the DC battery voltage to the variable AC required to drive the AC motor.
Includes dc-dc boost converter and dc-3φ ac inverter
Control system can operate in all-electric mode or in hybrid gas+electric mode
Partial-power electronics
This document discusses the generation of high voltage impulses. It describes impulsive and oscillatory transients and their causes. A 1.2/50 μs, 1000 kV wave represents an impulse voltage wave with a 1.2 μs front time and 50 μs tail time. Modified Marx circuits are used to generate high voltage impulses, with capacitors charged in stages through high resistance and discharged through spark gaps. Wave shaping is controlled through resistors and capacitors. Commercial impulse generators typically have 6 sets of resistors to control the waveform and are rated by voltage, number of stages, and stored energy.
This document provides an overview of high voltage direct current (HVDC) transmission systems. It discusses the motivations and components of HVDC systems, including converter stations and DC transmission lines. Some key advantages of HVDC are its ability to transmit large amounts of power over long distances with lower losses than alternating current systems. HVDC also allows asynchronous connections between AC systems and control over power flow direction.
This document discusses the generation of high impulse currents. It describes how a bank of capacitors charged in parallel can be discharged through an R-L circuit to produce large impulse currents. It also discusses the essential components of an impulse current generator, including charging units, capacitors, inductors, and triggering units. Additionally, it explains how trigatrons can be used in the tripping circuit to trigger the impulse generator through a smaller triggering pulse compared to using a three-electrode spark gap. Schematic diagrams are also provided to illustrate typical trigatron-based tripping circuits.
here dc-dc boost converter designed in MATLAB Simulink and MPPT controller designed in 2 methods(P&O and incremental conductance).
finally, I connect it to Ac grid via the Dc-Ac converter.
this entire system called grid-connected PV system.
Impulse generators are used to test electrical equipment by generating high voltage surges over short durations, simulating events like lightning strikes. A single-stage impulse generator uses capacitors and resistors to charge then discharge through a spark gap, producing an impulse. However, they are large and inefficient. A Marx generator improves on this design using multiple capacitors charged in parallel and discharged in series, multiplying the output voltage. While more compact and powerful, Marx generators still have long charge times and loss of efficiency due to the charging resistors.
The document discusses capacitance on transmission lines. It explains that capacitance occurs between parallel conductors due to potential differences, similar to capacitor plates, and depends on conductor size and spacing. For short power lines under 80km, capacitance is minor but becomes important for longer, higher voltage lines. It then examines the capacitance of three-phase lines with both equilateral and unsymmetrical conductor spacing, noting calculations are simpler if the line is transposed so each conductor occupies the same positions over cycles.
The document describes a project to design a microgrid using synchronverters. It discusses the challenges of instability in grids and proposes using synchronverters to control inverters like synchronous machines for stability. The project involves modeling synchronverters for a grid, wind farm, solar farm, and battery storage. Controllers are developed using synchronous machine models and droop functions. Simulations are conducted in MATLAB to test synchronization using PLL and self-synchronization, operation in set and droop modes, and response to load changes. Experimental results from the simulations demonstrate the synchronverters' frequency response and P-Q outputs in different operating conditions.
Lecture Outline
Introduction to subject
Application Areas
Power Electronic Devices
Power Converters
What is power electronics?
1) Definition
Power Electronics: is the electronics applied to conversion and control of electric power.
Prerequisites
Power electronics incorporates concepts from the fields of
Analog circuits
Electronic devices
Control systems
Power systems
Magnetics
Electric machines
Numerical simulation
Scope
It is not possible to build practical computers, cell phones, personal data devices, cars, airplanes, industrial processes, and other everyday products without power electronics.
Alternative energy systems such as wind generators, solar power, fuel cells, and others require power electronics to function.
Technology advances such as electric and hybrid vehicles, laptop computers, microwave ovens, flat-panel displays, LED lighting, and hundreds of other innovations were not possible until advances in power electronics enabled their implementation.
Although no one can predict the future, it is certain that power electronics will be at the heart of fundamental energy innovations.
Applications: Electric VehicleTesla Model S
Functions of the power electronics:
1. Convert the DC battery voltage to the variable AC required to drive the AC motor
240 V battery
Variable-frequency, variable-voltage AC drives the motor
AC motor propels the rear axle
Up to 330 kW (acceleration)
Up to 60 kW regenerative braking
2. Control charging of the battery
Interface to 240 V 60 Hz 1φ 100 A circuit in garage.
Control AC current waveform to be sinusoidal, unity power factor.
Control charging of battery to maximize life.
Applications: Hybrid VehiclesPrius
Power Electronics Module:
Convert the DC battery voltage to the variable AC required to drive the AC motor.
Includes dc-dc boost converter and dc-3φ ac inverter
Control system can operate in all-electric mode or in hybrid gas+electric mode
Partial-power electronics
This document discusses the generation of high voltage impulses. It describes impulsive and oscillatory transients and their causes. A 1.2/50 μs, 1000 kV wave represents an impulse voltage wave with a 1.2 μs front time and 50 μs tail time. Modified Marx circuits are used to generate high voltage impulses, with capacitors charged in stages through high resistance and discharged through spark gaps. Wave shaping is controlled through resistors and capacitors. Commercial impulse generators typically have 6 sets of resistors to control the waveform and are rated by voltage, number of stages, and stored energy.
This document provides an overview of high voltage direct current (HVDC) transmission systems. It discusses the motivations and components of HVDC systems, including converter stations and DC transmission lines. Some key advantages of HVDC are its ability to transmit large amounts of power over long distances with lower losses than alternating current systems. HVDC also allows asynchronous connections between AC systems and control over power flow direction.
This document discusses the generation of high impulse currents. It describes how a bank of capacitors charged in parallel can be discharged through an R-L circuit to produce large impulse currents. It also discusses the essential components of an impulse current generator, including charging units, capacitors, inductors, and triggering units. Additionally, it explains how trigatrons can be used in the tripping circuit to trigger the impulse generator through a smaller triggering pulse compared to using a three-electrode spark gap. Schematic diagrams are also provided to illustrate typical trigatron-based tripping circuits.
here dc-dc boost converter designed in MATLAB Simulink and MPPT controller designed in 2 methods(P&O and incremental conductance).
finally, I connect it to Ac grid via the Dc-Ac converter.
this entire system called grid-connected PV system.
Impulse generators are used to test electrical equipment by generating high voltage surges over short durations, simulating events like lightning strikes. A single-stage impulse generator uses capacitors and resistors to charge then discharge through a spark gap, producing an impulse. However, they are large and inefficient. A Marx generator improves on this design using multiple capacitors charged in parallel and discharged in series, multiplying the output voltage. While more compact and powerful, Marx generators still have long charge times and loss of efficiency due to the charging resistors.
The document discusses capacitance on transmission lines. It explains that capacitance occurs between parallel conductors due to potential differences, similar to capacitor plates, and depends on conductor size and spacing. For short power lines under 80km, capacitance is minor but becomes important for longer, higher voltage lines. It then examines the capacitance of three-phase lines with both equilateral and unsymmetrical conductor spacing, noting calculations are simpler if the line is transposed so each conductor occupies the same positions over cycles.
This document discusses the history and development of high voltage engineering. It begins with early experiments with static electricity by ancient Greeks. Key figures who contributed include Franklin, Faraday, Tesla, and Edison. Faraday's law established that a magnetic field can induce current in a wire. Advances allowed longer distance power transmission. Challenges included developing high voltage insulation. Numerical methods like finite element analysis are now used to model electric field distributions in complex high voltage components.
Short Circuit, Protective Device Coordinationmichaeljmack
This document discusses short-circuit calculations, protective device coordination, and arc flash analysis. It covers topics such as short-circuit fault types and calculations, the purpose of short-circuit studies, system components involved, and protective device coordination principles. Methods to perform arc flash analysis and mitigate incident energy exposure are also presented, such as improving protective device coordination settings, installing current limiting fuses or circuit breakers, and using Type 50 protective devices.
This document provides an overview of DC-DC converters including buck, boost, and buck-boost converters. It discusses:
1) How switching regulators operate by switching the transistor fully on and off to transfer power from the source to the load with near zero power loss, unlike linear regulators.
2) The basic operation of buck, boost, and buck-boost converters where the inductor current flows through the diode when the switch is open to regulate the output voltage.
3) Key parameters like duty cycle, inductance, capacitance, and switching frequency that determine the output voltage and ability to reduce voltage ripple in these converter circuits.
The document discusses vector control of permanent magnet synchronous motors (PMSM). It begins by describing the dynamic model of a PMSM, including assumptions made about the rotor flux. It then derives the stator equations in the rotor reference frame to model the PMSM similarly to an induction motor. Vector control of the PMSM is then derived from its dynamic model to decouple the torque and flux channels by controlling the stator currents in the d-q reference frame. This allows controlling the PMSM similarly to a separately excited DC motor.
Instantaneous Reactive Power Theory And Its Applicationsarunj89
Instantaneous Reactive Power Theory and its Applications to Active Power Filtering
The document discusses instantaneous reactive power (P-Q) theory, which was introduced by Hirofumi Akagi in 1983. P-Q theory defines instantaneous real and imaginary powers in the time domain, allowing it to be applied to non-sinusoidal systems. It has been widely used for harmonic compensation in active power filters. The document outlines the mathematical basis of P-Q theory, including Clarke transformations, definitions of instantaneous real and imaginary powers, and applications for compensating nonlinear loads. It also discusses developments and applications of P-Q theory, including its use in simulation and compensation of harmonic currents.
Loadability of line is defined as the extent of load which can flow through the line without exceeding the limitations. Line Loadability is expressed in percentage of Surge Impedance Loading of line. The limiting factor for line loading are: thermal limit, voltage drop limit and steady state stability.
This document summarizes the operation of a single phase AC voltage controller with an RL load. It describes how the voltage is controlled using pairs of thyristors (SCRs) through phase control. During operation, the first thyristor T1 is triggered at firing angle α and conducts until 180°. The second thyristor T2 is then triggered at 180°+α and conducts until 360°+α, producing an output voltage that is variable but at the same frequency as the input supply. The document also provides an example calculation for controlling 230V, 50Hz power into a 3Ω resistor and 4Ω inductor load, determining the firing angle range, maximum load and power, power factor,
This document provides a summary of maximum power point tracking (MPPT) technology for photovoltaic systems. It discusses modeling of solar cells and how their output is affected by irradiation and temperature. It also describes the basic operation of a boost converter used in MPPT systems. Several common MPPT algorithms are examined, including perturb and observe, incremental conductance, and other methods. Flow charts are provided to illustrate the perturb and observe and incremental conductance algorithms. The conclusion is that the incremental conductance method provides better performance than other methods under varying conditions.
This document discusses high voltage direct current (HVDC) electric power transmission. It provides an introduction to HVDC, outlines its history including the first HVDC transmission systems in Sweden and India. It describes the components used in HVDC including converter stations, rectifiers, filters and inverters. It discusses reasons for using HVDC over HVAC such as lower transmission losses and costs. Limitations of HVDC include costly terminal equipment and complex control systems. Applications include long distance and asynchronous transmission. The future may include fully converting generation to distribution systems to direct current.
The document summarizes HVDC (High Voltage Direct Current) transmission. It discusses why DC transmission is used over long distances, the key components of an HVDC system including converters and transmission lines, and different HVDC system configurations like monopolar, bipolar, and homopolar links. It also provides examples of HVDC applications in India and notes that while HVDC transmission has high costs, it offers benefits like reduced losses over long distances and increased power transmission stability and flexibility.
The document presents information on harmonic reduction in inverter output voltage. It defines harmonics as integral multiples of a fundamental frequency that result in a distorted waveform when added together. Common sources of harmonics are identified as lighting ballasts, UPS systems, AC drives, and DC drives. Methods for attenuating harmonics discussed include inductive reactance, passive filters, active filters, 12-pulse and 18-pulse rectifiers, PWM, transformer connections, stepped wave inverters, and multilevel inverters. The document recommends limits on voltage and current distortion set by IEEE 519 and compares harmonic reduction performance of different converter and inverter configurations.
This document discusses different methods for generating high voltages and currents, including cascade transformers, resonant transformers, and Tesla coils for AC voltages, and single-stage and Marx generators for impulse voltages. It also covers impulse current generation using a bank of parallel capacitors discharged through an R-L circuit. Cascade transformers consist of multiple transformer stages connected in series to achieve high voltages. Resonant transformers use tuning of the secondary circuit. Tesla coils produce high frequency AC through magnetic coupling of primary and secondary air-core coils.
Voltage source Converters as a building block of HVDC and FACTSKarthik Bharadwaj
This document discusses voltage source converters (VSCs) and their use in HVDC and FACTS systems. It provides background on VSCs and how they allow independent control of real and reactive power. The first HVDC transmission using VSC converters took place in 1997 in Sweden. VSCs generate AC voltage from DC and can control output voltage magnitude, phase, and frequency. When used for HVDC, multiple VSCs can be connected in series to reduce harmonics. FACTS devices using VSCs, such as STATCOMs, can control power flow and provide voltage regulation on transmission lines.
The document presents a detailed electromechanical model of a DFIG-based wind turbine connected to a power grid. It discusses different types of wind turbine generators including squirrel cage induction, synchronous, and doubly fed induction generators. It then focuses on modeling and simulating a DFIG system in MATLAB/Simulink. Control schemes for regulating pitch angle, DC link voltage, and fault analysis are studied. Simulation results show the DFIG is able to control power at variable wind speeds and regulate DC link voltage through pitch angle control. Future work opportunities to improve the control and reduce system costs are also outlined.
This document discusses voltage source converter (VSC) based high voltage direct current (HVDC) transmission. It explains that a VSC based HVDC link can be viewed as two static synchronous compensators connected by a DC link. There are two modes of operation depending on whether the DC capacitors are connected or not. Advantages of VSC based HVDC links over traditional line commutated converter based links include independent control of real and reactive power and the ability to absorb or supply reactive power. Key components of a VSC converter station are also outlined.
HVDC Bridge and Station Configurations
1. General HVDC – HVAC Comparisons
2. Components of a Converter Bridge
3. HVDC scheme configurations
Operation of the HVDC converter
1. General assumptions
2. Rectifier operation with uncontrolled valves and X = 0
3. Rectifier operation with controlled valves and X = 0
4. Rectifier operation with controlled valves and X 0
5. Inverter operation with controlled valves and X 0
6. Commutation and Commutation Failure
7. Reactive Power Requirements
8. Short-circuit capacity requirements for an HVDC terminal.
9. Harmonics and filtering on the AC and DC sides
The document discusses different types of resonant pulse inverters. It begins by explaining the disadvantages of traditional pulse-width modulation controlled converters, such as high switching losses and electromagnetic interference. It then introduces resonant pulse converters which minimize these issues by forcing the voltage and current to zero during switching. The document outlines various resonant converter topologies, including series and parallel resonant inverters as well as classes of converters that achieve zero-voltage or zero-current switching. It provides examples of half-bridge and full-bridge configurations for series resonant inverters with both unidirectional and bidirectional switches. Finally, it briefly discusses the operation of parallel resonant inverters.
This document provides an overview of trends in power electronics. It discusses how power electronics is used for efficient power conversion and control through semiconductor devices. It also outlines several applications of power electronics such as motor drives, lighting, power supplies and renewable energy systems. The document mentions some professional organizations and conferences related to power electronics as well as major companies in the field.
The document provides an introduction and overview of the Power Electronics 2 module. It discusses typical AC/DC/AC power conversion systems using line-side and motor-side converters. The module aims to provide knowledge of power electronics technologies including three-phase rectification, resonant converters, inverters, and high power converter structures. It outlines the lecture topics, recommendations, and reviews three-phase voltage supplies.
The document discusses nodal analysis, which is an extension of Kirchhoff's Current Law (KCL) concepts for analyzing circuits with multiple nodes. It provides an example of setting up nodal equations to solve for unknown node voltages in a circuit containing independent current sources. The document also explains that nodal analysis allows complex circuits to be simplified by setting up a system of simultaneous equations using node voltages as variables.
This document discusses the history and development of high voltage engineering. It begins with early experiments with static electricity by ancient Greeks. Key figures who contributed include Franklin, Faraday, Tesla, and Edison. Faraday's law established that a magnetic field can induce current in a wire. Advances allowed longer distance power transmission. Challenges included developing high voltage insulation. Numerical methods like finite element analysis are now used to model electric field distributions in complex high voltage components.
Short Circuit, Protective Device Coordinationmichaeljmack
This document discusses short-circuit calculations, protective device coordination, and arc flash analysis. It covers topics such as short-circuit fault types and calculations, the purpose of short-circuit studies, system components involved, and protective device coordination principles. Methods to perform arc flash analysis and mitigate incident energy exposure are also presented, such as improving protective device coordination settings, installing current limiting fuses or circuit breakers, and using Type 50 protective devices.
This document provides an overview of DC-DC converters including buck, boost, and buck-boost converters. It discusses:
1) How switching regulators operate by switching the transistor fully on and off to transfer power from the source to the load with near zero power loss, unlike linear regulators.
2) The basic operation of buck, boost, and buck-boost converters where the inductor current flows through the diode when the switch is open to regulate the output voltage.
3) Key parameters like duty cycle, inductance, capacitance, and switching frequency that determine the output voltage and ability to reduce voltage ripple in these converter circuits.
The document discusses vector control of permanent magnet synchronous motors (PMSM). It begins by describing the dynamic model of a PMSM, including assumptions made about the rotor flux. It then derives the stator equations in the rotor reference frame to model the PMSM similarly to an induction motor. Vector control of the PMSM is then derived from its dynamic model to decouple the torque and flux channels by controlling the stator currents in the d-q reference frame. This allows controlling the PMSM similarly to a separately excited DC motor.
Instantaneous Reactive Power Theory And Its Applicationsarunj89
Instantaneous Reactive Power Theory and its Applications to Active Power Filtering
The document discusses instantaneous reactive power (P-Q) theory, which was introduced by Hirofumi Akagi in 1983. P-Q theory defines instantaneous real and imaginary powers in the time domain, allowing it to be applied to non-sinusoidal systems. It has been widely used for harmonic compensation in active power filters. The document outlines the mathematical basis of P-Q theory, including Clarke transformations, definitions of instantaneous real and imaginary powers, and applications for compensating nonlinear loads. It also discusses developments and applications of P-Q theory, including its use in simulation and compensation of harmonic currents.
Loadability of line is defined as the extent of load which can flow through the line without exceeding the limitations. Line Loadability is expressed in percentage of Surge Impedance Loading of line. The limiting factor for line loading are: thermal limit, voltage drop limit and steady state stability.
This document summarizes the operation of a single phase AC voltage controller with an RL load. It describes how the voltage is controlled using pairs of thyristors (SCRs) through phase control. During operation, the first thyristor T1 is triggered at firing angle α and conducts until 180°. The second thyristor T2 is then triggered at 180°+α and conducts until 360°+α, producing an output voltage that is variable but at the same frequency as the input supply. The document also provides an example calculation for controlling 230V, 50Hz power into a 3Ω resistor and 4Ω inductor load, determining the firing angle range, maximum load and power, power factor,
This document provides a summary of maximum power point tracking (MPPT) technology for photovoltaic systems. It discusses modeling of solar cells and how their output is affected by irradiation and temperature. It also describes the basic operation of a boost converter used in MPPT systems. Several common MPPT algorithms are examined, including perturb and observe, incremental conductance, and other methods. Flow charts are provided to illustrate the perturb and observe and incremental conductance algorithms. The conclusion is that the incremental conductance method provides better performance than other methods under varying conditions.
This document discusses high voltage direct current (HVDC) electric power transmission. It provides an introduction to HVDC, outlines its history including the first HVDC transmission systems in Sweden and India. It describes the components used in HVDC including converter stations, rectifiers, filters and inverters. It discusses reasons for using HVDC over HVAC such as lower transmission losses and costs. Limitations of HVDC include costly terminal equipment and complex control systems. Applications include long distance and asynchronous transmission. The future may include fully converting generation to distribution systems to direct current.
The document summarizes HVDC (High Voltage Direct Current) transmission. It discusses why DC transmission is used over long distances, the key components of an HVDC system including converters and transmission lines, and different HVDC system configurations like monopolar, bipolar, and homopolar links. It also provides examples of HVDC applications in India and notes that while HVDC transmission has high costs, it offers benefits like reduced losses over long distances and increased power transmission stability and flexibility.
The document presents information on harmonic reduction in inverter output voltage. It defines harmonics as integral multiples of a fundamental frequency that result in a distorted waveform when added together. Common sources of harmonics are identified as lighting ballasts, UPS systems, AC drives, and DC drives. Methods for attenuating harmonics discussed include inductive reactance, passive filters, active filters, 12-pulse and 18-pulse rectifiers, PWM, transformer connections, stepped wave inverters, and multilevel inverters. The document recommends limits on voltage and current distortion set by IEEE 519 and compares harmonic reduction performance of different converter and inverter configurations.
This document discusses different methods for generating high voltages and currents, including cascade transformers, resonant transformers, and Tesla coils for AC voltages, and single-stage and Marx generators for impulse voltages. It also covers impulse current generation using a bank of parallel capacitors discharged through an R-L circuit. Cascade transformers consist of multiple transformer stages connected in series to achieve high voltages. Resonant transformers use tuning of the secondary circuit. Tesla coils produce high frequency AC through magnetic coupling of primary and secondary air-core coils.
Voltage source Converters as a building block of HVDC and FACTSKarthik Bharadwaj
This document discusses voltage source converters (VSCs) and their use in HVDC and FACTS systems. It provides background on VSCs and how they allow independent control of real and reactive power. The first HVDC transmission using VSC converters took place in 1997 in Sweden. VSCs generate AC voltage from DC and can control output voltage magnitude, phase, and frequency. When used for HVDC, multiple VSCs can be connected in series to reduce harmonics. FACTS devices using VSCs, such as STATCOMs, can control power flow and provide voltage regulation on transmission lines.
The document presents a detailed electromechanical model of a DFIG-based wind turbine connected to a power grid. It discusses different types of wind turbine generators including squirrel cage induction, synchronous, and doubly fed induction generators. It then focuses on modeling and simulating a DFIG system in MATLAB/Simulink. Control schemes for regulating pitch angle, DC link voltage, and fault analysis are studied. Simulation results show the DFIG is able to control power at variable wind speeds and regulate DC link voltage through pitch angle control. Future work opportunities to improve the control and reduce system costs are also outlined.
This document discusses voltage source converter (VSC) based high voltage direct current (HVDC) transmission. It explains that a VSC based HVDC link can be viewed as two static synchronous compensators connected by a DC link. There are two modes of operation depending on whether the DC capacitors are connected or not. Advantages of VSC based HVDC links over traditional line commutated converter based links include independent control of real and reactive power and the ability to absorb or supply reactive power. Key components of a VSC converter station are also outlined.
HVDC Bridge and Station Configurations
1. General HVDC – HVAC Comparisons
2. Components of a Converter Bridge
3. HVDC scheme configurations
Operation of the HVDC converter
1. General assumptions
2. Rectifier operation with uncontrolled valves and X = 0
3. Rectifier operation with controlled valves and X = 0
4. Rectifier operation with controlled valves and X 0
5. Inverter operation with controlled valves and X 0
6. Commutation and Commutation Failure
7. Reactive Power Requirements
8. Short-circuit capacity requirements for an HVDC terminal.
9. Harmonics and filtering on the AC and DC sides
The document discusses different types of resonant pulse inverters. It begins by explaining the disadvantages of traditional pulse-width modulation controlled converters, such as high switching losses and electromagnetic interference. It then introduces resonant pulse converters which minimize these issues by forcing the voltage and current to zero during switching. The document outlines various resonant converter topologies, including series and parallel resonant inverters as well as classes of converters that achieve zero-voltage or zero-current switching. It provides examples of half-bridge and full-bridge configurations for series resonant inverters with both unidirectional and bidirectional switches. Finally, it briefly discusses the operation of parallel resonant inverters.
This document provides an overview of trends in power electronics. It discusses how power electronics is used for efficient power conversion and control through semiconductor devices. It also outlines several applications of power electronics such as motor drives, lighting, power supplies and renewable energy systems. The document mentions some professional organizations and conferences related to power electronics as well as major companies in the field.
The document provides an introduction and overview of the Power Electronics 2 module. It discusses typical AC/DC/AC power conversion systems using line-side and motor-side converters. The module aims to provide knowledge of power electronics technologies including three-phase rectification, resonant converters, inverters, and high power converter structures. It outlines the lecture topics, recommendations, and reviews three-phase voltage supplies.
The document discusses nodal analysis, which is an extension of Kirchhoff's Current Law (KCL) concepts for analyzing circuits with multiple nodes. It provides an example of setting up nodal equations to solve for unknown node voltages in a circuit containing independent current sources. The document also explains that nodal analysis allows complex circuits to be simplified by setting up a system of simultaneous equations using node voltages as variables.
A transformer transfers electrical energy from one circuit to another through mutual induction without changing frequency but changing voltage and current. It has a primary coil and secondary coil; a changing magnetic field in the primary coil induces a voltage in the secondary coil. Transformers come in core form or shell form and can be modeled using an equivalent circuit with resistances and reactances. The transformer's performance can be analyzed using open circuit and short circuit tests.
This document outlines the syllabus for a VLSI design course. The syllabus covers five units: (1) CMOS technology, including history, characteristics, and enhancements; (2) circuit characterization and simulation; (3) combinational and sequential circuit design; (4) CMOS testing; and (5) specification using Verilog HDL. The first unit provides an introduction to CMOS technology, discussing MOS transistors, CMOS processes like p-well and n-well, and layout design rules. Subsequent units cover circuit analysis, common circuit elements, testing approaches, and hardware description languages. References include textbooks on VLSI design, digital circuits, and Verilog HDL.
Incomplete PPT on first topic.pptx [Autosaved] [Autosaved].pptShubhobrataRudr
The document provides information on rotating electrical machines. It discusses the basic concepts of electromechanical energy conversion that occurs due to changes in flux linkages resulting from mechanical motion. It describes different types of machine windings including armature, field, AC, and distributed windings. The document also covers the generation of a rotating magnetic field in a three-phase system using three coils with currents that are equal in magnitude and phase-displaced by 120 degrees, resulting in a constant magnitude rotating magnetic field. It derives expressions for the induced voltages in coils and discusses factors that affect the induced voltages.
This document covers ideal transformer theory and operation, including:
- Explaining how an ideal transformer operates based on Lenz's law and induced voltages being proportional to turns ratio
- Deriving equations for voltage ratio, current ratio, and impedance transformation based on turns ratio for an ideal transformer
- Identifying assumptions of an ideal transformer and limitations of practical transformers
- Modeling a non-ideal transformer using a circuit including magnetizing reactance and core loss resistance to represent no-load losses
- Working through examples of calculating voltages, currents, impedances, and no-load parameters for transformers.
The MATLAB File by Akshit Jain .pdf on .Akshit Jain
"Unlock the Power of Data Analysis and Computational Modeling with this MATLAB File!
This MATLAB file is a versatile tool designed to revolutionize your data analysis and computational modeling processes. Whether you're a scientist, engineer, researcher, or student, MATLAB empowers you to tackle complex problems with ease.
With an intuitive interface and robust functionality, this file enables you to manipulate, visualize, and interpret data with precision. From statistical analysis and signal processing to machine learning and optimization, MATLAB offers a comprehensive suite of tools to meet your diverse needs.
Additionally, this file provides access to a vast library of built-in functions and toolboxes, allowing you to customize and extend its capabilities to suit your specific requirements. Whether you're analyzing experimental data, simulating dynamic systems, or developing algorithms, MATLAB empowers you to turn your ideas into reality.
Experience the power and versatility of MATLAB today and unlock new possibilities in data analysis and computational modeling!"
1) The document is a lab manual for an Electrical Engineering measurement lab course. It details 10 experiments involving measuring devices like oscilloscopes, multimeters, and bridges.
2) The first experiment involves studying oscilloscopes, their working principles, and different types of probes. Block diagrams and features of oscilloscopes are described.
3) Power factor is defined as the ratio between real power and apparent power. A power factor meter and phase shifter circuit are explained along with calculations for power factor correction by adding a capacitor.
This chapter discusses sinusoidal waveforms which are fundamental to alternating current (AC) circuits. Sine waves are characterized by their amplitude and period. The chapter covers definitions of peak, RMS, average values and how to relate period and frequency. It also discusses how sinusoidal voltages are generated and defines concepts like phase shift and phasors which allow analysis of AC circuits using trigonometry. The chapter concludes with an overview of pulse waveforms.
The document discusses sinusoidal waveforms, which are fundamental to alternating current. It defines key characteristics of sine waves such as amplitude, period, frequency, and how they are related. The document also covers how sinusoidal voltages are generated by AC generators and function generators. It describes methods for specifying the voltage value of sine waves, including peak, RMS, average and peak-to-peak values. Finally, it introduces phasors as a way to represent rotating vectors for analyzing AC circuits using trigonometry.
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Synchronverters: Inverters that Mimic Synchronous Generators
1. S YNCHRONVERTERS : I NVERTERS THAT M IMIC
S YNCHRONOUS G ENERATORS
Qing-Chang Zhong, Fellow of IET, SMIEEE
ZhongQC@ieee.org
Chair in Control and Systems Engineering
Dept. of Automatic Control and Systems Engineering
The University of Sheffield
United Kingdom
http://zhongqc.staff.shef.ac.uk
(Joint work with George Weiss, Tel Aviv University
2. Outline
Motivation and relevant works
Modelling of synchronous generators
Implementation of a synchronverter
Operation of a synchronverter
Simulation results
Experimental setup and results
Potential applications
An overview of other research activities
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 2/41
3. Motivation
Transition from centralised generation to distributed
generation
Wind power
Solar energy
Tide and wave energy
CHP
Increasing share of renewable energy
UK: 20% by 2020
EU: 22% target for the share of renewable energy
sources and an 18% target for the share of CHP in
electricity generation by 2010
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 3/41
4. Challenges
Regulation of system frequency and voltage
Currently most inverters feed currents to the grid and
the grid cannot control these sources. Inverters will
have to take part in the regulation of power systems in
the near future.
There is an increasing need of voltage controlled
inverters to connect with weak grids
Threat to power system stability: Inverters have different
dynamics from conventional synchronous generators
The need of smooth transition of knowledge
These sources are connected to the grid via common
key devices called inverters so it is possible to tackle
these problems via properly controlling the inverters.
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 4/41
5. Our solution
Turning inverters into synchronous generators, mathe-
matically. Such inverters are called synchronverters.
Operate voltage source inverters to mimic
synchronous generators
The energy flow between the DC bus and the AC
bus changes direction automatically according to
the grid frequency
Take part in the power system regulation of
frequency and voltage: the same as synchronous
generators (externally)
Dynamically behave like synchronous generators
(internally)
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 5/41
6. Relevant works
Virtual synchronous machine (VISMA) by Beck and Hesse
The voltages at the point of common coupling with the grid are measured to
calculate the phase currents of the VISMA in real time.
These currents are used as reference currents for a current-controlled inverter. If the
current tracking error is small, then the inverter behaves like a synchronous
machine, justifying the term VISMA. However, a synchronous generator is a
voltage source.
The grid integration using control algorithms for SG was left as future work
Virtual synchronous generator (VSG) by VSYNC
Add a short-term energy storage system to provide virtual inertia
The inverter itself does not have the dynamics of a synchronous generator
Frequency/voltage drooping
e.g. by De Brabandere, Bolsens, Van den Keybus, Woyte, Driesen, Belmans
and by Sao and Lehn
The inverter itself does not have the dynamics of a synchronous generator
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 6/41
7. Some basics about inverters
+
Circuit
Ls , R s va Lg , R g Breaker
ia vga
ea vb
VDC ib vgb
eb
vc
ec ic vgc
C
-
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 7/41
8. Modelling of synchronous generators
Motivation and relevant works
Modelling of synchronous generators
Electrical part
Mechanical part
Implementation of a synchronverter
Operation of a synchronverter
Simulation results
Experimental setup and results
Potential applications
An overview of other research activities
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 8/41
9. SG: Electrical part
Consider a round rotor (θ = 0 )
machine (without dam-
per windings), with p Rotor field axis
pairs of poles per phase
Rs , L
(and p pairs of poles
Rotation
on the rotor) and with
no saturation effects in M M
the iron core. The
N
Field voltage
stator windings can be
Rs , L Rs , L
regarded as concentra-
ted coils having self-
inductance L and mu- M
tual inductance −M .
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 9/41
10. Notation
Define
Φa ia
Φ = Φb , i = ib
Φc ic
and
cos θ sin θ
cos θ = cos(θ − 2π ) ,
3
sin θ = sin(θ − 2π ) .
3
cos(θ − 4π )
3 sin(θ − 4π )
3
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 10/41
11. Flux linkage
The field (or rotor) winding can be regarded as a concentrated
coil having self-inductance Lf . The mutual inductance between
the field coil and each of the three stator coils is Mf cos θ. Assume
that the neutral line is not connected, then ia + ib + ic = 0. The
stator flux linkages are
Φ = Ls i + Mf if cos θ, (1)
where Ls = L + M , and the field flux linkage is
Φf = Lf if + Mf i, cos θ , (2)
where ·, · denotes the conventional inner product. The second
term Mf i, cosθ is constant if the three phase currents are sinu-
soidal (as functions of θ) and balanced.
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 11/41
12. Voltage
T
The phase terminal voltages v = va vb vc are
dΦ di
v = −Rs i − = −Rs i − Ls + e, (3)
dt dt
where Rs is the resistance of the stator windings and
T
e= ea eb ec is the back emf
˙sin θ − Mf dif cos θ.
e = Mf if θ (4)
dt
The field terminal voltage, from (2), is
dΦf
vf = −Rf if − , (5)
dt
where Rf is the resistance of the rotor winding.
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 12/41
13. SG: Mechanical part
The mechanical part of the machine is governed by
¨ ˙
J θ = Tm − Te − Dp θ, (6)
where J is the moment of inertia of all parts rotating
with the rotor, Tm is the mechanical torque, Te is the
electromagnetic toque and Dp is a damping factor. Te
can be found from the energy E stored in the machine
magnetic field, i.e.,
1 1
E = i, Φ + if Φf
2 2
1 1 2
= i, Ls i + Mf if i, cos θ + Lf if .
2 2
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 13/41
14. Electromagnetic torque Te
∂E ∂E
Te = =− .
∂θm Φ, Φf constant ∂θm i, if constant
Since the mechanical rotor angle θm satisfies θ = pθm ,
Te = pMf if i, sin θ . (7)
Note that if i = i0 sin ϕ then
3
Te = pMf if i0 sin ϕ, sin θ = pMf if i0 cos(θ − ϕ).
2
Note also that if if is constant then (7) with (4) yield
˙
Te θm = i, e .
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 14/41
15. Provision of a neutral line
The above analysis is based on the assumption that there is no
neutral line. If a neutral line is connected, then
ia + ib + ic = iN ,
where iN is the current flowing through the neutral line. Then, the
formula for the stator flux linkages (1) becomes
1
Φ = Ls i + Mf if cos θ − 1 M iN
1
and the phase terminal voltages (3) become
di 1 diN
v = −Rs i − Ls + 1 M + e,
dt 1 dt
where e is given by (4). The other formulae are not affected.
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 15/41
16. Real and reactive power
Define the generated real power P and reactive power Q as
P = i, e and Q = i, eq ,
π
where eq has the same amplitude as e but with a phase delayed by 2
, i.e.,
˙ π ˙
eq = θMf if sin(θ − ) = −θMf if cos θ.
2
Then, the real power and reactive power are, respectively,
˙
P = θMf if i, sin θ ,
˙
Q = −θMf if i, cos θ . (8)
Note that if i = i0 sin ϕ (as would be the case in the sinusoidal steady state), then
˙ 3˙
P = θMf if i, sin θ = θMf if i0 cos(θ − ϕ),
2
˙ 3˙
Q = −θMf if i, cos θ = θMf if i0 sin(θ − ϕ).
2
These coincide with the conventional definitions for real power and reactive power.
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 16/41
17. Implementation of a synchronverter
Motivation and relevant works
Modelling of synchronous generators
Implementation of a synchronverter
Electronic part
Power part
Interaction between the two parts
Operation of a synchronverter
Simulation results
Experimental setup and results
Potential applications
An overview of other research activities
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 17/41
18. The electronic part (without control)
It is advantageous to assume that the field (rotor) win-
ding of the synchronverter is fed by an adjustable DC
current source if instead of a voltage source vf . In this
case, the terminal voltage vf varies, but this is irrele-
vant. As long as if is constant, there is
˙sin θ − Mf dif cos θ.
e = Mf if θ
dt
˙
= θMf if sin θ. (9)
Also the effect of the neutral current iN can be ignored
if M is chosen as 0, because
di 1 diN
v = −Rs i − Ls + 1 M + e.
dt 1 dt
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 18/41
19. ¨ = 1 (Tm − Te − Dpθ),
θ ˙
J Dp
-
Te = pMf if i, sin θ , Tm 1 θ& 1 θ
Js s
-
Te
Eqn. (7)
˙
e = θMf if sin θ, Q Eqn. (8)
Eqn. (9) e
Mf if i
˙
Q = −θMf if i, cos θ .
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 19/41
20. The power part
This part consists of three phase legs and a three-
phase LC filter, which is used to suppress the switching
noise. If the inverter is to be connected to the grid, then
three more inductors Lg (with series resistance Rg ) and
a circuit breaker can be used to interface with the grid.
+
Circuit
Ls , R s va Lg , R g Breaker
ia vga
ea vb
VDC ib vgb
eb
vc
ec ic vgc
C
-
di
v = −Rs i − Ls + e.
dt
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 20/41
21. Interaction between the two parts
The switches in the inverter are operated so that
the average values of ea , eb and ec over a
switching period should be equal to e given in
(9), which can be achieved by the usual PWM
techniques.
The phase currents are fed back to the electronic
part.
+
Dp
Circuit
Ls , R s va Lg , R g Breaker
ia vga
- ea
Tm 1 θ& 1 θ vb
VDC ib vgb
Js s eb
- vc
ec ic vgc
Te
Eqn. (7)
Q Eqn. (8)
Eqn. (9)
C
e
-
Mf if i
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 21/41
22. Operation of a synchronverter
Motivation and relevant works
Modelling of synchronous generators
Implementation of a synchronverter
Operation of a synchronverter
Operation objectives
Regulation of P and frequency drooping
Regulation of Q and voltage drooping
Complete electronic part
Simulation results
Experimental setup and results
Potential applications
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 22/41
23. Operation objectives
The frequency should be maintained, e.g. at 50Hz
The output voltage should be maintained, e.g. at
230V
The generated/consumed real power should be re-
gulated
The reactive power should be regulated, if connec-
ted to the grid
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 23/41
24. Frequency drooping
The speed regulation system of the prime mover for a conventio-
nal synchronous generator can be implemented in a synchronver-
˙
ter by comparing the virtual angular speed θ with the angular fre-
˙
quency reference θr before feeding it into the damping block Dp .
As a result, the damping factor Dp actually behaves as the fre-
quency drooping coefficient, which is defined as the ratio of the
required change of torque ∆T to the change of speed (frequency)
∆θ:˙
∆T ˙
∆T θn Tmn
Dp = = ,
∆θ˙ Tmn ∆θ ˙ θn
˙
where Tmn is the nominal mechanical torque. Because of the
built-in frequency drooping mechanism, a synchronverter auto-
matically shares the load with other inverters of the same type
and with SGs connected on the same bus.
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 24/41
25. Complete electronic part
Dp θr
&
-
Reset θg
Pset p Tm 1 θ& 1 θ
θ&
n Js s
-
θc
Fromto the power part
Te
Eqn. (7)
Q Eqn. (8)
PWM
Eqn. (9)
e generation
- Mf if
Qset 1 i
Ks
Dq
- Amplitude v fb
vm detection
vr
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 25/41
26. Voltage drooping
The regulation of reactive power Q flowing out of the synchron-
verter can be realised similarly. Define the voltage drooping co-
efficient Dq as the ratio of the required change of reactive power
∆Q to the change of voltage ∆v:
∆Q ∆Q vn Qn
Dq = = ,
∆v Qn ∆v vn
where Qn is the nominal reactive power and vn is the nominal
amplitude of terminal voltage v. The difference between the refe-
rence voltage vr and the amplitude of the feedback voltage vf b is
amplified with the voltage drooping coefficient Dq before adding
to the difference between the set point Qset and the reactive power
Q. The resulting signal is then fed into an integrator with a gain
1
K
to generate Mf if .
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 26/41
27. The synchronverter under simu./exp.
Parameters Values Parameters Values
Ls 0.45 mH Lg 0.45 mH
Rs 0.135 Ω Rg 0.135 Ω
C 22 µF Frequency 50 Hz
R 1000 Ω Line voltage 20.78 Vrms
Rated power 100 W DC voltage 42V
Dp 0.2026 Dq 117.88
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 27/41
28. Frequency (Hz)
50.2
Simulation results 50.1
50
50Hz
49.95Hz
49.9
49.8
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
t = 0: Simulation started to 2
Amplitude of v-vg (V)
1.5
allow the PLL and 1
0.5
synchronverter to start up; 0
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
Normalised v
1.05
t = 1s: Circuit breaker on; 1.025
1
t = 2s: Pset = 80W; 0.975
0.95
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
P (W)
t = 3s: Qset = 60Var; 140
120
100
80
60
t = 4s: drooping mechanism 40
20
0
-20
enabled; 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
Q (Var)
80
t = 5s: grid voltage decreased 60
40
20
by 5%. 0
-20
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
Time (Second)
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 28/41
29. Experimental setup
The synchronverter is connected to the grid, three-phase 400V
50Hz, via a circuit breaker and a step-up transformer.
Q.-C. Z
HONG :S :I
YNCHRONVERTERS M S G – p. 29/41
NVERTERS THAT IMIC YNCHRONOUS ENERATORS
30. Experimental results
The experiments were carried out according to the fol-
lowing sequence of actions:
1. start the system, but keeping all the IGBTs off;
2. start operating the IGBTs, roughly at 2s;
3. turn the circuit breaker on, roughly at 6s;
4. apply instruction Pset = 70W, roughly at 11s;
5. apply instruction Qset = 30 Var, roughly at 16s;
6. enable the drooping mechanism, roughly at 22s;
7. stop data recording, roughly at 27s.
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 30/41
33. Potential applications
Distributed generation and renewable energy, allowing
these sources to take part in the regulation of power system
frequency, voltage and overall stability.
Uninterrupted power supplies (UPS), in particular, the
parallel operation of multiple UPSs
Isolated/distributed power supplies, e.g. to replace rotary
frequency converters
Static synchronous compensator (STATCOM) to improve
power factor
HVDC transmission (at the receiving end)
Induction heating
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 33/41
34. Current status of the technology
Patent application filed, entered into
the PCT stage and the national phase.
A Senior Research Fellowship
(one-year) was awarded by the Royal
Academy of Engineering to further
develop this technology for 2009-2010.
Conference paper appeared
Journal paper appeared in IEEE Trans.
on Industrial Electronics
Applied to AC drives — AC Ward
Leonard drive systems
Numerous requests from worldwide
researchers Q.-C. Z :S
HONG YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 34/41
35. Summary
An approach is proposed to operate inverters to mimic synchronous
generators after establishing the mathematical model of synchronous
generators. Such inverters are called synchronverters.
Synchronverters can be operated in island mode or grid-connected
mode. When it is connected to the grid, it can take part in the regulation
of power system via frequency and voltage drooping.
No external communication is needed for parallel operation.
The energy flow between the DC bus and the AC bus changes direction
automatically according to the grid frequency.
It can disconnect from the grid and can automatically re-synchronise
and re-connect with the grid.
Potential applications include grid connection of renewable energy
sources, parallel operation of UPS, HVDC transmission, STATCOM,
isolated/distributed power supplies etc.
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 35/41
36. Further details
Full-text paper:
http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&
arnumber=5456209
BibTex entry:
@ARTICLE{ZhongW.IEEE:09, author = {Q.-C.
Zhong and G. Weiss}, title = {Synchronverters:
{I}nverters that mimic synchronous generators}, jour-
nal = {{IEEE} Trans. Ind. Electron.}, year = {2011},
volume = {58}, pages = {1259–1267}, number = {4},
month = {Apr.} }
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 36/41
37. Other activities in PE
DC grid/bus
AC bus
G G
~
Generic Topology
…
~ Grid
or
Load
G Energy
~
…
Storage
System
~
1. MPPT 5. Energy management 7. Power quality improvement
Technologies
2. AC drives 6. Bi-directional DC/DC conversion 8. Parallel operation of inverters
3. DC/DC conversion 9. Grid-friendly connection
4. DC drives 10. Power flow control
11. Synchronisation
12. Provision of a neutral line
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 37/41
38. Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 38/41
39. Activities in automotive engineering
Rapid control prototyping (RCP) and
Hardware-in-the-loop (HIL) simulation
dSPACE systems
MicroGen systems
Developing a powerful HIL system
Hybrid electrical vehicles
HEV driver model
AC Ward Leonard drive systems
Charging systems with grid support
EPSRC Future project: Energy flow/storage/management
systems
Initial work done on engine control
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 39/41
40. Activities in chemical engineering
Control of integral processes with dead-time: A research monograph, Control of Integral
Processes with Dead Time, jointly with Antonio Visioli from Italy, is to appear in 2010.
Disturbance observer-based control strategy
Dead-beat response
Stability region on the control parameter space
Achievable specifications etc
Practical experience with a production line
Advances in Industrial Control
16 reactors, controlled by 3 industrial computers
Antonio Visioli
Qing-Chang Zhong
Effective object code > 100 KB (Intel 8086 assembler)
1 Control of
Analogue control variables and measurements etc. Integral Processes
with Dead Time
Continuous Stirred Tank Reactor (CSTR) System
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 40/41
41. Activities in control theory
Mainly three threads:
Robust control of time-delay systems: A series of fundamental problems in this area have
been solved:
Projections
J-spectral factorisation
Delay-type Nehari problem
Standard H ∞ problem of single-delay systems
Unified Smith predictor
Realisation of distributed delays in controllers
Infinite-dimensional systems: applied the generic theory of infinite-dimensional systems
to time-delay systems and solved problems about feedback stabilizability, approximate
controllability, passivity etc
Uncertainty and disturbance estimator (UDE)-based robust control: can be applied to li-
near or nonlinear, time-varying or time-invariant systems with or without delays; attracted
several Indian groups to work on this.
Q.-C. Z HONG : S YNCHRONVERTERS : I NVERTERS THAT M IMIC S YNCHRONOUS G ENERATORS – p. 41/41