Modelling of bidirectional full bridge DC-DC converter as one of the most applicable converters has received significant attention. Mathematical modelling reduces the simulation time in comparison with detailed circui...Modelling of bidirectional full bridge DC-DC converter as one of the most applicable converters has received significant attention. Mathematical modelling reduces the simulation time in comparison with detailed circuit response;moreover it is convenient for controller design purpose. Due to simple and effective methodology, average state space is the most common method among the modelling methods. In this paper a bidirectional full bridge converter is modelled by average state space and for each mode of operations a controller is designed. Attained mathematical model results are in a close agreement with detailed circuit simulation.展开更多
The design of a bidirectional dc-dc power converter specifically for a distributed energy application is presented. The existing two different DC voltage battery bank of the distributed generation needs to interlink e...The design of a bidirectional dc-dc power converter specifically for a distributed energy application is presented. The existing two different DC voltage battery bank of the distributed generation needs to interlink each other using a bi-directional dc-dc converter in order to minimize the unbalance of the output load currents of the three inverters connected to electric grid system. Through this connection, a current can flow from one system to another or vice versa depending on which systems need the current most. Thus, unbalanced currents of the grid line have been minimized and the reliability and performance of the DER grid connected system has been increased. A detailed mathematical analysis of the converter under steady state and transient condition are presented. Mathematical models for boost and buck modes are being derived and the simulink model is constructed in order to simulate the system. Moreover, the model has been validated on the actual operation of the converter, showing that the simulated results in Matlab Simulink are consistent with the experimental ones.展开更多
Wide bandgap(WBG)semiconductors,such as silicon carbide(SiC)and gallium nitride(GaN),exhibit superior physical properties and demonstrate great potential for replacing conventional silicon(Si)semiconductors with WBG t...Wide bandgap(WBG)semiconductors,such as silicon carbide(SiC)and gallium nitride(GaN),exhibit superior physical properties and demonstrate great potential for replacing conventional silicon(Si)semiconductors with WBG technology,pushing the boundaries of power devices to handle higher blocking voltages,switching frequencies,output power levels,and operating temperatures.However,tradeoffs in switching performance and converter efficiency when substituting GaN devices for Si and SiC counterparts are not well-defined,especially in a cascode configuration.Additional research with further detailed investigation and analysis is necessitated for medium-voltage GaN devices in power converter applications.Therefore,the aim of this research is to experimentally investigate the impact of emerging 650/900 V cascode GaN devices on bidirectional dc-dc converters that are suitable for energy storage and distributed renewable energy systems.Dynamic characteristics of Si,SiC,and cascode GaN power devices are examined through the double-pulse test(DPT)circuit at different gate resistance values,device currents,and DC bus voltages.Furthermore,the switching behavior and energy loss as well as the rate of voltage and current changes over the time are studied and analyzed at various operating conditions.A 500 W experimental converter prototype is implemented to validate the benefits of cascode GaN devices on the converter operation and performance.Comprehensive analysis of the power losses and efficiency improvements for Si-based,SiC-based,and GaN-based converters are performed and evaluated as the switching frequency,working temperature,and output power level are in-creased.The experimental results reveal significant improvements in switching performance and energy efficiency from the emerging cascode GaN devices in the bidirectional converters.展开更多
The interests on energy storage schemes, bidirectional dc-dc converter and uninterruptible power supplies have been increasing nowadays as there wide researches are undertaken in the area of electric vehicles. A modif...The interests on energy storage schemes, bidirectional dc-dc converter and uninterruptible power supplies have been increasing nowadays as there wide researches are undertaken in the area of electric vehicles. A modified bi directional class-E resonant dc-dc converter is introduced here in this proposed topology for the application in electric vehicles. The advantages of soft switching techniques have been utilized for making analysis simple. The main advantage here in this system is that it can operate in a wide range of frequencies with minimal switching loss in transistors. This paper elaborates a detailed analysis on converter design and the same has been simulated and verified in Matlab/Simulink.展开更多
By establishing the discrete iterative mapping model of a current mode controlled buck-boost converter, this paper studies the mechanism of mode shift and stability control of the buck-boost converter operating in dis...By establishing the discrete iterative mapping model of a current mode controlled buck-boost converter, this paper studies the mechanism of mode shift and stability control of the buck-boost converter operating in discontinuous conduction mode with a ramp compensation current. With the bifurcation diagrazn, Lyapunov exponent spectrum, time- domain waveform and parameter space map, the performance of the buck-boost converter circuit utilizing a compensating ramp current has been analysed. The obtained results indicate that the system trajectory is weakly chaotic and strongly intermittent under discontinuous conduction mode. By using ramp compensation, the buck-boost converter can shift from discontinuous conduction mode to continuous conduction mode, and effectively operates in the stable period-one region.展开更多
In this paper, the fractional-order mathematical model and the fractional-order state-space averaging model of the Buck-Boost converter in continuous conduction mode (CCM) are established based on the fractional cal...In this paper, the fractional-order mathematical model and the fractional-order state-space averaging model of the Buck-Boost converter in continuous conduction mode (CCM) are established based on the fractional calculus and the Adomian decomposition method. Some dynamical properties of the current-mode controlled fractional-order Buck- Boost converter are analysed. The simulation is accomplished by using SIMULINK. Numerical simulations are presented to verify the analytical results and we find that bifurcation points will be moved backward as α and β vary. At the same time, the simulation results show that the converter goes through different routes to chaos.展开更多
By analyzing the output voltage ripple of a buck-boost converter with large equivalent series resistance(ESR) of output capacitor, one valley voltage-mode controller for buck-boost converter is proposed. Considering...By analyzing the output voltage ripple of a buck-boost converter with large equivalent series resistance(ESR) of output capacitor, one valley voltage-mode controller for buck-boost converter is proposed. Considering the fact that the increasing and decreasing slopes of the inductor current are assumed to be constant during each switching cycle, an especial sampleddata model of valley voltage-mode controlled buck-boost converter is established. Based on this model, the dynamical effect of an output-capacitor time-constant on the valley voltage-mode controlled buck-boost converter is revealed and analyzed via the bifurcation diagrams, the movements of eigenvalues, the Lyapunov exponent spectra, the boundary equations,and the operating-state regions. It is found that with gradual reduction of output-capacitor time-constant, the buck-boost converter in continuous conduction mode(CCM) shows the evolutive dynamic behavior from period-1 to period-2, period-4, period-8, chaos, and invalid state. The stability boundary and the invalidated boundary are derived theoretically by stability analysis, where the stable state of valley voltage-mode controlled buck-boost converter can enter into an unstable state, and the converter can shift from the operation region to a forbidden region. These results verified by time-domain waveforms and phase portraits of both simulation and experiment indicate that the sampled-data model is correct and the time constant of the output capacitor is a critical factor for valley voltage-mode controlled buck-boost converter, which has a significant effect on the dynamics as well as control stability.展开更多
An intelligent fuzzy logic inference pipeline for the control of a dc-dc buck-boost converter was designed and built using a semi-custom VLSI chip. The fuzzy linguistics describing the switching topologies of the conv...An intelligent fuzzy logic inference pipeline for the control of a dc-dc buck-boost converter was designed and built using a semi-custom VLSI chip. The fuzzy linguistics describing the switching topologies of the converter was mapped into a look-up table that was synthesized into a set of Boolean equations. A VLSI chip–a field programmable gate array (FPGA) was used to implement the Boolean equations. Features include the size of RAM chip independent of number of rules in the knowledge base, on-chip fuzzification and defuzzification, faster response with speeds over giga fuzzy logic inferences per sec (FLIPS), and an inexpensive VLSI chip. The key application areas are: 1) on-chip integrated controllers;and 2) on-chip co-integration for entire system of sensors, circuits, controllers, and detectors for building complete instrument systems.展开更多
A novel electron beam welder ( EBW) power supply was developed. Compared with the traditional 3-phase contrail 12-pulse rectifying supplies, it requires a much lower step-up ratio transformer, but a much less output...A novel electron beam welder ( EBW) power supply was developed. Compared with the traditional 3-phase contrail 12-pulse rectifying supplies, it requires a much lower step-up ratio transformer, but a much less output ripple voltage can be obtained. The design of the main circuit of this new power supply is based on PWM buck-boost converter topology. In developing the system a fuzzy PID control method is adopted because of the strong non-linearity and big signal working conditions of the circuit system. The SABER-MATLAB models and fuzzy algorithm were used in developing the fuzzy PID controller. The co-simulation and experimental results displayed that the unit introduced herein has the characteristics of high control precision and antinterference capability.展开更多
In this paper, direct model predictive control(DMPC) of the noninverting buck-boost DC-DC converter with magnetic coupling between input and output is proposed. Unlike most of the other converters, the subject convert...In this paper, direct model predictive control(DMPC) of the noninverting buck-boost DC-DC converter with magnetic coupling between input and output is proposed. Unlike most of the other converters, the subject converter has the advantage of exhibiting minimum phase behavior in the boost mode. However, a major issue that arises in the classical control of the converter is the dead zone near the transition of the buck and boost mode. The reason for the dead zone is practically unrealizable duty cycles, which are close to zero or unity, of pulse width modulation(PWM) near the transition region. To overcome this issue, we propose to use DMPC. In DMPC, the switches are manipulated directly by the controller without the need of PWM.Thereby, avoiding the dead zone altogether. DMPC also offers several other advantages over classical techniques that include optimality and explicit current constraints. Simulations of the proposed DMPC technique on the converter show that the dead zone has been successfully avoided. Moreover, simulations show that the DMPC technique results in a significantly improved performance as compared to the classical control techniques in terms of response time, reference tracking, and overshoot.展开更多
This paper shows DC and small-signal circuit models for the PWM DC to DC buck, boost and back/ boost converters with the equivalent series resistance of the inductor. The DC voltage transfer function and the efficienc...This paper shows DC and small-signal circuit models for the PWM DC to DC buck, boost and back/ boost converters with the equivalent series resistance of the inductor. The DC voltage transfer function and the efficiency of the converter are derived from the DC model. Small-signal open-loop characteristics are derived from the small-signal model based on a state variable model. A design example proves the performance of the circuit and verification of the model.展开更多
This paper proposes a design and implementation of the bi-directional DC-DC converter for Wind Energy Conversion System. The proposed project consists of boost DC/DC converter, bi-directional DC/DC converter (BDC), pe...This paper proposes a design and implementation of the bi-directional DC-DC converter for Wind Energy Conversion System. The proposed project consists of boost DC/DC converter, bi-directional DC/DC converter (BDC), permanent magnet DC generator and batteries. A DC-DC boost converter is interface with proposed wind system to step up the initial generator voltage and maintain constant output voltage. The fluctuation nature of wind makes them unsuitable for standalone operation. To overcome the drawbacks an energy storage device is used in the proposed system to compensate the fluctuations and to maintain a smooth and continuous power flow in all operating modes to load. Bi-directional DC-DC converter (BDC) is capable of transforming energy between two DC buses. It can operate as a boost converter which supplies energy to the load when the wind generator output power is greater than the required load power. It also operates in buck mode which charges from DC bus when output power is less than the required load power. The proposed converter reduces the component losses and increases the performance of the overall system. The complete system is implemented in MATLAB/SIMULINK and verified with hardware.展开更多
The high potentiality of integrating renewable energies,such as photovoltaic,into a modern electrical microgrid system,using DC-to-DC converters,raises some issues associated with controller loop design and system sta...The high potentiality of integrating renewable energies,such as photovoltaic,into a modern electrical microgrid system,using DC-to-DC converters,raises some issues associated with controller loop design and system stability.The generalized state space average model(GSSAM)concept was consequently introduced to design a DC-to-DC converter controller in order to evaluate DC-to-DC converter performance and to conduct stability studies.This paper presents a GSSAM for parallel DC-to-DC converters,namely:buck,boost,and buck-boost converters.The rationale of this study is that modern electrical systems,such as DC networks,hybrid microgrids,and electric ships,are formed by parallel DC-to-DC converters with separate DC input sources.Therefore,this paper proposes a GSSAM for any number of parallel DC-to-DC converters.The proposed GSSAM is validated and investigated in a time-domain simulation environment,namely a MATLAB/SIMULINK.The study compares the steady-state,transient,and oscillatory performance of the state-space average model with a fully detailed switching model.展开更多
The primary challenge in renewable-energy utilization is an energy-storage system involving its power converter.The systems have to promise high efficiency,reliability and durability.Also,all of these can be realized ...The primary challenge in renewable-energy utilization is an energy-storage system involving its power converter.The systems have to promise high efficiency,reliability and durability.Also,all of these can be realized at an economical cost.Buck and boost converters connected in parallel can convert power in both directions.It is the basic non-isolated bidirectional topology commonly used with energy-storage systems.The primary issue with the buck-boost non-isolated bidirectional converter is how to enhance its performance,so the modification involving this topology is still conducted.This paper examines 29 proposed converters from 30 research publications published in the last 10 years,the most recent of which focuses on modified non-isolated bidirectional converters based on the buck-boost topology.These are classified into eight modification schemes,which involve adding new components or circuits to the base topology.Each is evaluated against six parameters:the number of components,control complexity,power-rating applications,soft-switching ability,efficiency outcome and capacity to minimize losses.Moreover,each modified non-isolated bidirectional converter was compared from the renewable-energy-based power-generation-source perspective utilized.Based on these studies,researchers might think of ways to improve the buck-boost converter by changing it to make a new non-isolated bidirectional converter that can be used in systems that need it.展开更多
The paper proposes a novel three-phase voltage-fed quasi-Z-source ac-ac converter topology to overcome the shortcomings of the traditional three-phase AC-AC chopper.The quantitative relationship between the output vol...The paper proposes a novel three-phase voltage-fed quasi-Z-source ac-ac converter topology to overcome the shortcomings of the traditional three-phase AC-AC chopper.The quantitative relationship between the output voltage and duty-ratio is deduced by investigating the topology and operating principle.It can provide buck-boost function,and the output voltage of the circuit can keep stable in the case of voltage sagging.Simulation is performed using the MATLAB software,and the experimental circuit is built based on the simulation results,the simulation and experimental results verify the correctness and feasibility of the proposed ac-ac converter topology.展开更多
A hybrid bidirectional DC/DC converter(BDC)is proposed as the fundamental DC/DC module in solid-state transformers,which combines a bidirectional LLC converter and a dual-active-bridge(DAB)converter.Integrated with a ...A hybrid bidirectional DC/DC converter(BDC)is proposed as the fundamental DC/DC module in solid-state transformers,which combines a bidirectional LLC converter and a dual-active-bridge(DAB)converter.Integrated with a mutual control scheme,both parts of this hybrid BDC can be unified into an interdependent community.In this hybrid BDC,the LLC converter supports the output voltage and improves stability by working at the resonant frequency mode and the DAB converter enhances the BDC power capability by controlling the LLC output current constant.The BDC can achieve the full-load-range soft switching of all active switches by designing the auxiliary inductor of LLC and the minimum output current of DAB.By comparing to the single DAB,the proposed BDC has the higher phase and gain margin which means the BDC improved the relative stability based on Nyquist criterion.To solve the bidirectional power control problem,a dead-band voltage control logic is adopted which can determine the BDC’s power direction based on the output voltage change.A 200 V experimental system has verified the aforementioned features and functions of the BDC.展开更多
文摘Modelling of bidirectional full bridge DC-DC converter as one of the most applicable converters has received significant attention. Mathematical modelling reduces the simulation time in comparison with detailed circuit response;moreover it is convenient for controller design purpose. Due to simple and effective methodology, average state space is the most common method among the modelling methods. In this paper a bidirectional full bridge converter is modelled by average state space and for each mode of operations a controller is designed. Attained mathematical model results are in a close agreement with detailed circuit simulation.
文摘The design of a bidirectional dc-dc power converter specifically for a distributed energy application is presented. The existing two different DC voltage battery bank of the distributed generation needs to interlink each other using a bi-directional dc-dc converter in order to minimize the unbalance of the output load currents of the three inverters connected to electric grid system. Through this connection, a current can flow from one system to another or vice versa depending on which systems need the current most. Thus, unbalanced currents of the grid line have been minimized and the reliability and performance of the DER grid connected system has been increased. A detailed mathematical analysis of the converter under steady state and transient condition are presented. Mathematical models for boost and buck modes are being derived and the simulink model is constructed in order to simulate the system. Moreover, the model has been validated on the actual operation of the converter, showing that the simulated results in Matlab Simulink are consistent with the experimental ones.
文摘Wide bandgap(WBG)semiconductors,such as silicon carbide(SiC)and gallium nitride(GaN),exhibit superior physical properties and demonstrate great potential for replacing conventional silicon(Si)semiconductors with WBG technology,pushing the boundaries of power devices to handle higher blocking voltages,switching frequencies,output power levels,and operating temperatures.However,tradeoffs in switching performance and converter efficiency when substituting GaN devices for Si and SiC counterparts are not well-defined,especially in a cascode configuration.Additional research with further detailed investigation and analysis is necessitated for medium-voltage GaN devices in power converter applications.Therefore,the aim of this research is to experimentally investigate the impact of emerging 650/900 V cascode GaN devices on bidirectional dc-dc converters that are suitable for energy storage and distributed renewable energy systems.Dynamic characteristics of Si,SiC,and cascode GaN power devices are examined through the double-pulse test(DPT)circuit at different gate resistance values,device currents,and DC bus voltages.Furthermore,the switching behavior and energy loss as well as the rate of voltage and current changes over the time are studied and analyzed at various operating conditions.A 500 W experimental converter prototype is implemented to validate the benefits of cascode GaN devices on the converter operation and performance.Comprehensive analysis of the power losses and efficiency improvements for Si-based,SiC-based,and GaN-based converters are performed and evaluated as the switching frequency,working temperature,and output power level are in-creased.The experimental results reveal significant improvements in switching performance and energy efficiency from the emerging cascode GaN devices in the bidirectional converters.
文摘The interests on energy storage schemes, bidirectional dc-dc converter and uninterruptible power supplies have been increasing nowadays as there wide researches are undertaken in the area of electric vehicles. A modified bi directional class-E resonant dc-dc converter is introduced here in this proposed topology for the application in electric vehicles. The advantages of soft switching techniques have been utilized for making analysis simple. The main advantage here in this system is that it can operate in a wide range of frequencies with minimal switching loss in transistors. This paper elaborates a detailed analysis on converter design and the same has been simulated and verified in Matlab/Simulink.
基金Project supported by the National Natural Science Foundations of China (Grant Nos 50677056 and 60472059)
文摘By establishing the discrete iterative mapping model of a current mode controlled buck-boost converter, this paper studies the mechanism of mode shift and stability control of the buck-boost converter operating in discontinuous conduction mode with a ramp compensation current. With the bifurcation diagrazn, Lyapunov exponent spectrum, time- domain waveform and parameter space map, the performance of the buck-boost converter circuit utilizing a compensating ramp current has been analysed. The obtained results indicate that the system trajectory is weakly chaotic and strongly intermittent under discontinuous conduction mode. By using ramp compensation, the buck-boost converter can shift from discontinuous conduction mode to continuous conduction mode, and effectively operates in the stable period-one region.
基金Project supported by the National Natural Science Foundation of China (Grant No. 51177117)the Specialized Research Fund for the Doctoral Program of Higher Education,China (Grant No. 20100201110023)
文摘In this paper, the fractional-order mathematical model and the fractional-order state-space averaging model of the Buck-Boost converter in continuous conduction mode (CCM) are established based on the fractional calculus and the Adomian decomposition method. Some dynamical properties of the current-mode controlled fractional-order Buck- Boost converter are analysed. The simulation is accomplished by using SIMULINK. Numerical simulations are presented to verify the analytical results and we find that bifurcation points will be moved backward as α and β vary. At the same time, the simulation results show that the converter goes through different routes to chaos.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61371033 and 51407054)the Foundation for the Author of National Excellent Doctoral Dissertation of China(Grant No.201442)the Fundamental Research Funds for the Central Universities of China(Grant No.2682016CX035)
文摘By analyzing the output voltage ripple of a buck-boost converter with large equivalent series resistance(ESR) of output capacitor, one valley voltage-mode controller for buck-boost converter is proposed. Considering the fact that the increasing and decreasing slopes of the inductor current are assumed to be constant during each switching cycle, an especial sampleddata model of valley voltage-mode controlled buck-boost converter is established. Based on this model, the dynamical effect of an output-capacitor time-constant on the valley voltage-mode controlled buck-boost converter is revealed and analyzed via the bifurcation diagrams, the movements of eigenvalues, the Lyapunov exponent spectra, the boundary equations,and the operating-state regions. It is found that with gradual reduction of output-capacitor time-constant, the buck-boost converter in continuous conduction mode(CCM) shows the evolutive dynamic behavior from period-1 to period-2, period-4, period-8, chaos, and invalid state. The stability boundary and the invalidated boundary are derived theoretically by stability analysis, where the stable state of valley voltage-mode controlled buck-boost converter can enter into an unstable state, and the converter can shift from the operation region to a forbidden region. These results verified by time-domain waveforms and phase portraits of both simulation and experiment indicate that the sampled-data model is correct and the time constant of the output capacitor is a critical factor for valley voltage-mode controlled buck-boost converter, which has a significant effect on the dynamics as well as control stability.
文摘An intelligent fuzzy logic inference pipeline for the control of a dc-dc buck-boost converter was designed and built using a semi-custom VLSI chip. The fuzzy linguistics describing the switching topologies of the converter was mapped into a look-up table that was synthesized into a set of Boolean equations. A VLSI chip–a field programmable gate array (FPGA) was used to implement the Boolean equations. Features include the size of RAM chip independent of number of rules in the knowledge base, on-chip fuzzification and defuzzification, faster response with speeds over giga fuzzy logic inferences per sec (FLIPS), and an inexpensive VLSI chip. The key application areas are: 1) on-chip integrated controllers;and 2) on-chip co-integration for entire system of sensors, circuits, controllers, and detectors for building complete instrument systems.
文摘A novel electron beam welder ( EBW) power supply was developed. Compared with the traditional 3-phase contrail 12-pulse rectifying supplies, it requires a much lower step-up ratio transformer, but a much less output ripple voltage can be obtained. The design of the main circuit of this new power supply is based on PWM buck-boost converter topology. In developing the system a fuzzy PID control method is adopted because of the strong non-linearity and big signal working conditions of the circuit system. The SABER-MATLAB models and fuzzy algorithm were used in developing the fuzzy PID controller. The co-simulation and experimental results displayed that the unit introduced herein has the characteristics of high control precision and antinterference capability.
文摘In this paper, direct model predictive control(DMPC) of the noninverting buck-boost DC-DC converter with magnetic coupling between input and output is proposed. Unlike most of the other converters, the subject converter has the advantage of exhibiting minimum phase behavior in the boost mode. However, a major issue that arises in the classical control of the converter is the dead zone near the transition of the buck and boost mode. The reason for the dead zone is practically unrealizable duty cycles, which are close to zero or unity, of pulse width modulation(PWM) near the transition region. To overcome this issue, we propose to use DMPC. In DMPC, the switches are manipulated directly by the controller without the need of PWM.Thereby, avoiding the dead zone altogether. DMPC also offers several other advantages over classical techniques that include optimality and explicit current constraints. Simulations of the proposed DMPC technique on the converter show that the dead zone has been successfully avoided. Moreover, simulations show that the DMPC technique results in a significantly improved performance as compared to the classical control techniques in terms of response time, reference tracking, and overshoot.
文摘This paper shows DC and small-signal circuit models for the PWM DC to DC buck, boost and back/ boost converters with the equivalent series resistance of the inductor. The DC voltage transfer function and the efficiency of the converter are derived from the DC model. Small-signal open-loop characteristics are derived from the small-signal model based on a state variable model. A design example proves the performance of the circuit and verification of the model.
文摘This paper proposes a design and implementation of the bi-directional DC-DC converter for Wind Energy Conversion System. The proposed project consists of boost DC/DC converter, bi-directional DC/DC converter (BDC), permanent magnet DC generator and batteries. A DC-DC boost converter is interface with proposed wind system to step up the initial generator voltage and maintain constant output voltage. The fluctuation nature of wind makes them unsuitable for standalone operation. To overcome the drawbacks an energy storage device is used in the proposed system to compensate the fluctuations and to maintain a smooth and continuous power flow in all operating modes to load. Bi-directional DC-DC converter (BDC) is capable of transforming energy between two DC buses. It can operate as a boost converter which supplies energy to the load when the wind generator output power is greater than the required load power. It also operates in buck mode which charges from DC bus when output power is less than the required load power. The proposed converter reduces the component losses and increases the performance of the overall system. The complete system is implemented in MATLAB/SIMULINK and verified with hardware.
文摘The high potentiality of integrating renewable energies,such as photovoltaic,into a modern electrical microgrid system,using DC-to-DC converters,raises some issues associated with controller loop design and system stability.The generalized state space average model(GSSAM)concept was consequently introduced to design a DC-to-DC converter controller in order to evaluate DC-to-DC converter performance and to conduct stability studies.This paper presents a GSSAM for parallel DC-to-DC converters,namely:buck,boost,and buck-boost converters.The rationale of this study is that modern electrical systems,such as DC networks,hybrid microgrids,and electric ships,are formed by parallel DC-to-DC converters with separate DC input sources.Therefore,this paper proposes a GSSAM for any number of parallel DC-to-DC converters.The proposed GSSAM is validated and investigated in a time-domain simulation environment,namely a MATLAB/SIMULINK.The study compares the steady-state,transient,and oscillatory performance of the state-space average model with a fully detailed switching model.
基金supported and funded by the Higher Education Leading Applied Research(PTUPT)programme of the Ministry of Education,Culture,Research,and Technology of the Republic of Indonesia under contract number 011/PL.PTUPT/BRIn.LPPM/VI/2022the Indonesia Endowment Funds for Education(LPDP),Ministry of Finance of the Republic of Indonesia[number:20200811214083].
文摘The primary challenge in renewable-energy utilization is an energy-storage system involving its power converter.The systems have to promise high efficiency,reliability and durability.Also,all of these can be realized at an economical cost.Buck and boost converters connected in parallel can convert power in both directions.It is the basic non-isolated bidirectional topology commonly used with energy-storage systems.The primary issue with the buck-boost non-isolated bidirectional converter is how to enhance its performance,so the modification involving this topology is still conducted.This paper examines 29 proposed converters from 30 research publications published in the last 10 years,the most recent of which focuses on modified non-isolated bidirectional converters based on the buck-boost topology.These are classified into eight modification schemes,which involve adding new components or circuits to the base topology.Each is evaluated against six parameters:the number of components,control complexity,power-rating applications,soft-switching ability,efficiency outcome and capacity to minimize losses.Moreover,each modified non-isolated bidirectional converter was compared from the renewable-energy-based power-generation-source perspective utilized.Based on these studies,researchers might think of ways to improve the buck-boost converter by changing it to make a new non-isolated bidirectional converter that can be used in systems that need it.
文摘The paper proposes a novel three-phase voltage-fed quasi-Z-source ac-ac converter topology to overcome the shortcomings of the traditional three-phase AC-AC chopper.The quantitative relationship between the output voltage and duty-ratio is deduced by investigating the topology and operating principle.It can provide buck-boost function,and the output voltage of the circuit can keep stable in the case of voltage sagging.Simulation is performed using the MATLAB software,and the experimental circuit is built based on the simulation results,the simulation and experimental results verify the correctness and feasibility of the proposed ac-ac converter topology.
文摘A hybrid bidirectional DC/DC converter(BDC)is proposed as the fundamental DC/DC module in solid-state transformers,which combines a bidirectional LLC converter and a dual-active-bridge(DAB)converter.Integrated with a mutual control scheme,both parts of this hybrid BDC can be unified into an interdependent community.In this hybrid BDC,the LLC converter supports the output voltage and improves stability by working at the resonant frequency mode and the DAB converter enhances the BDC power capability by controlling the LLC output current constant.The BDC can achieve the full-load-range soft switching of all active switches by designing the auxiliary inductor of LLC and the minimum output current of DAB.By comparing to the single DAB,the proposed BDC has the higher phase and gain margin which means the BDC improved the relative stability based on Nyquist criterion.To solve the bidirectional power control problem,a dead-band voltage control logic is adopted which can determine the BDC’s power direction based on the output voltage change.A 200 V experimental system has verified the aforementioned features and functions of the BDC.