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
In recent years, Z-source inverters (ZSI) have been proposed as an replacement power conversion concept which it has both voltage buck and boost abilities. In addition, ZSI doesn’t require dead-time to protection sho...In recent years, Z-source inverters (ZSI) have been proposed as an replacement power conversion concept which it has both voltage buck and boost abilities. In addition, ZSI doesn’t require dead-time to protection short circuit at two switches any of the same phase leg in the inverter bridge and to achieve optimal harmonic of current, voltage. This paper presents two different control methods (CM) for ZSI. The aim of this study to compare between two modulation methods, there are modi?ed space vector pulse width modulation method (MSVM) and the simple boost control (SBC) about the unique harmonic performance features, the total average and peak switching device power of the inverter system. In addition, this paper also analyzes about the ability exceed modulation index in linear region of two CM using MATLAB/Simulink.展开更多
This paper does some theoretical analysis and simulation studies on the most common topologies of Z-source inverter.As we all know,the traditional Z-source inverter has some problems,such as the voltage of the capacit...This paper does some theoretical analysis and simulation studies on the most common topologies of Z-source inverter.As we all know,the traditional Z-source inverter has some problems,such as the voltage of the capacitor which belongs to this topology is higher and there is a startup shock,which caused researchers proposed a variety of improved Z-source topologies to solve these problems.Some of these topologies can increase boost capacity,and some can reduce the capacitor voltage.However,these topologies can improve only part of the problems of the traditional Z-source inverter,which leads to that the users are hard to choose which topologies.Faced with this situation,eleven Z-source topologies are analyzed in terms of boost capacity,inductance start-up current,capacitance stress and economy in this paper.Finally,two kinds of promising topologies were gotten.展开更多
A cost-effective component minimized embedded controlled Z-source inverter for induction motor drive is presented. The proposed topology combines the advantages of a traditional four-switch three-phase inverter with t...A cost-effective component minimized embedded controlled Z-source inverter for induction motor drive is presented. The proposed topology combines the advantages of a traditional four-switch three-phase inverter with the advantages of the z impedance network (two inductors in series and two X connected capacitors). This new topology, besides the self-boost property, has low switch count and it can operate as a buck-boost inverter. As a result, the new embedded controlled reduced switch Z-source inverter system provides ride through capability during voltage sags, reduces line harmonics, improves power factor, reliability and extends output voltage range. Analysis, simulation and experiment result will be presented to demonstrate these new features.展开更多
Z-source inverter can boost the voltage of the DC-side, allow the two switches of the same bridge arm conducting at the same time and it has some other advantages. The zero-sequence current flows through the fourth le...Z-source inverter can boost the voltage of the DC-side, allow the two switches of the same bridge arm conducting at the same time and it has some other advantages. The zero-sequence current flows through the fourth leg of the three-phase four-leg inverter so the three-phase four-leg inverter can work with unbalanced load. This paper presents a Z-source three-phase four-leg inverter which combines a Z-source network with three-phase four-leg inverter. The circuit uses simple SPWM modulation technique and the fourth bridge arm uses fully compensated control method. The inverter can maintain a symmetrical output voltage when the proposed scheme under the unbalanced load.展开更多
Nowadays, Z-source inverters (ZSI) are one of the most emerging topologies in field of power electronics. This paper deals with brief review of Z-source inverter, comprehensive study of its various topologies and sign...Nowadays, Z-source inverters (ZSI) are one of the most emerging topologies in field of power electronics. This paper deals with brief review of Z-source inverter, comprehensive study of its various topologies and significance of ZSI in modern industry. Different PWM techniques are used to obtain wider modulation range and easier real time implementation. This paper provides a systematic reference for future scientists for further development and advancement of ZSI.展开更多
This paper presents a modification in pulse width modulation (PWM) scheme with unequal shoot-through distribution for the Z-source inverter (ZSI) which can minimize ripples in the current through the Z-source indu...This paper presents a modification in pulse width modulation (PWM) scheme with unequal shoot-through distribution for the Z-source inverter (ZSI) which can minimize ripples in the current through the Z-source inductors as well as the voltage across the Z-source capacitors. For the same system parameters, the proposed control technique provides better voltage boost across the Z-source capacitor, DC-link, and also the AC output voltage than the traditional PWM. The ripples in the Z-network elements are found to be reduced by 75 % in the proposed modulation scheme with optimum harmonic profile in the AC output. Since the Zqnetwork requirement will be based on the ripple profile of the elements, the Z-network requirements can be greatly reduced. The effectiveness of the proposed modulation scheme has been simulated in Matlab/Simulink software and the results are validated by the experiment in the laboratory.展开更多
This paper presents a single-phase Z-source inverter as a power conditioning system for a single phase utility connected system. Z-source inverter is a single-stage topology that has buck-boost feature, which is possi...This paper presents a single-phase Z-source inverter as a power conditioning system for a single phase utility connected system. Z-source inverter is a single-stage topology that has buck-boost feature, which is possible because of additional shoot through state introduced in zero state of the conventional inverter pulse width modulation and provides desired output AC voltage. Small distributed generation (DG) system with alternate energy sources requires power conditioning units with low cost, high efficiency and tolerance to wide range of input voltage variation and has to perform various functions such as dc-ac conversion, system control and achieve power quality norms. To meet some of these requirements a two-loop control strategy for ac side control with grid current feedback with PI control and inner filter capacitor current feedback with proportional control and on dc side PID control for Z-source capacitor voltage regulation are employed, which gives good transient response also suppress load and source disturbances effectively. Theoretical analysis of proposed scheme is established and then simulation results are presented to validate proposed control strategy.展开更多
Quasi Z-source converter is a single stage soft switched power converter derived from Z-source converter topology, employing an impedance network coupling the source with the converter. The quasi Z-source source conve...Quasi Z-source converter is a single stage soft switched power converter derived from Z-source converter topology, employing an impedance network coupling the source with the converter. The quasi Z-source source converter can buck or boost the voltage and current flow is bidirectional. The duty cycle of the switch can be adjusted to maintain constant voltage during load change. To obtain constant output voltage, proper controller design is a must. This paper presents closed loop control of quasi Z-source converter using PI controller where controller parameters are estimated using the small signal model of the entire system. The transfer function of the system with AC sweep is used to obtain appropriate proportional and integral gain constants to reduce transient dynamics and to reduce steady state error.展开更多
A new ride through strategy is introduced in a three-level dual Z-source inverter, for isolation under semiconductor switching failure condition. Here the output will have no significant decrease in the amplitude and ...A new ride through strategy is introduced in a three-level dual Z-source inverter, for isolation under semiconductor switching failure condition. Here the output will have no significant decrease in the amplitude and quality. Instead of diodes, the triacs are added to the inverter source ends, as it can perform a bidirectional power transfer also it can operate well in both low and high voltage operating conditions. The faulted part can be isolated by simply altering the firing pulses for turning on/off the triacs using the carrier based SPWM technique and resulting in a boosting output with zero common mode voltage. Consequently, it forms a common floating point or null point with a zero common mode voltage. It is experimentally verified by using MATLAB, and digital oscilloscope.展开更多
文中提出一种新型单级式隔离型模块化多电平级联变换器(isolated modular multilevel cascade converter,I-MMCC),其具有中压三相交流(medium voltage three-phase AC,MVAC_((T-P)))、中压单相交流(medium voltage single phase AC,MVAC...文中提出一种新型单级式隔离型模块化多电平级联变换器(isolated modular multilevel cascade converter,I-MMCC),其具有中压三相交流(medium voltage three-phase AC,MVAC_((T-P)))、中压单相交流(medium voltage single phase AC,MVAC_((S-P)))和低压直流(low voltage DC,LVDC)3种电压端口。该变换器可实现从LVDC到MVAC的单级式功率变换,MVAC_((T-P))与MVAC_((S-P))电压端口能够实现同频或变频的AC-AC功率自由变换,其单极性调制策略可避免隔离型AC-AC矩阵变换器双向开关管换流暂态过程中出现的电压尖峰等问题。首先,介绍I-MMCC子模块拓扑结构与调制策略,并建立子模块及单相I-MMCC平均等效数学模型;其次,分析MVAC_((T-P))与MVAC_((S-P))端口变频–变压工作原理、稳态功率与端口特性,对单相交流端口基于正交虚拟电路概念,建立控制模型,并推导出MVAC_((S-P))、MVAC_((T-P))端口功率约束关系。最后,通过搭建一套实验样机验证所提出拓扑结构的有效性和优越性。展开更多
电力弹簧(electric spring,ES)作为一种电能质量优化装置,对关键负载与非关键负载进行区分使得电力弹簧在对关键负载进行保护时,非关键负载无法运行在其额定电压下,而且其调压能力受到线路参数的限制。针对传统ES在实际电网中工作时的...电力弹簧(electric spring,ES)作为一种电能质量优化装置,对关键负载与非关键负载进行区分使得电力弹簧在对关键负载进行保护时,非关键负载无法运行在其额定电压下,而且其调压能力受到线路参数的限制。针对传统ES在实际电网中工作时的被动性,文中提出一种基于双极性直接式AC-AC变换器的主动电力弹簧(AC-AC based active electric spring,AC-AES)实现分布式调压。AC-AES不再对关键负载与非关键负载进行区分,对用户负载进行统一控制,从而使其调压变得主动。最后,通过仿真和实验分别验证所提装置通过调节电压调控负载功率的可行性,以及在波动电网中稳定负载电压的能力。展开更多
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In recent years, Z-source inverters (ZSI) have been proposed as an replacement power conversion concept which it has both voltage buck and boost abilities. In addition, ZSI doesn’t require dead-time to protection short circuit at two switches any of the same phase leg in the inverter bridge and to achieve optimal harmonic of current, voltage. This paper presents two different control methods (CM) for ZSI. The aim of this study to compare between two modulation methods, there are modi?ed space vector pulse width modulation method (MSVM) and the simple boost control (SBC) about the unique harmonic performance features, the total average and peak switching device power of the inverter system. In addition, this paper also analyzes about the ability exceed modulation index in linear region of two CM using MATLAB/Simulink.
基金This project supported by National Natural Science Foundation of China(61573239)The Key Science and Technology Plan of Shanghai Science and Technology Commission(14110500700).
文摘This paper does some theoretical analysis and simulation studies on the most common topologies of Z-source inverter.As we all know,the traditional Z-source inverter has some problems,such as the voltage of the capacitor which belongs to this topology is higher and there is a startup shock,which caused researchers proposed a variety of improved Z-source topologies to solve these problems.Some of these topologies can increase boost capacity,and some can reduce the capacitor voltage.However,these topologies can improve only part of the problems of the traditional Z-source inverter,which leads to that the users are hard to choose which topologies.Faced with this situation,eleven Z-source topologies are analyzed in terms of boost capacity,inductance start-up current,capacitance stress and economy in this paper.Finally,two kinds of promising topologies were gotten.
文摘A cost-effective component minimized embedded controlled Z-source inverter for induction motor drive is presented. The proposed topology combines the advantages of a traditional four-switch three-phase inverter with the advantages of the z impedance network (two inductors in series and two X connected capacitors). This new topology, besides the self-boost property, has low switch count and it can operate as a buck-boost inverter. As a result, the new embedded controlled reduced switch Z-source inverter system provides ride through capability during voltage sags, reduces line harmonics, improves power factor, reliability and extends output voltage range. Analysis, simulation and experiment result will be presented to demonstrate these new features.
文摘Z-source inverter can boost the voltage of the DC-side, allow the two switches of the same bridge arm conducting at the same time and it has some other advantages. The zero-sequence current flows through the fourth leg of the three-phase four-leg inverter so the three-phase four-leg inverter can work with unbalanced load. This paper presents a Z-source three-phase four-leg inverter which combines a Z-source network with three-phase four-leg inverter. The circuit uses simple SPWM modulation technique and the fourth bridge arm uses fully compensated control method. The inverter can maintain a symmetrical output voltage when the proposed scheme under the unbalanced load.
文摘Nowadays, Z-source inverters (ZSI) are one of the most emerging topologies in field of power electronics. This paper deals with brief review of Z-source inverter, comprehensive study of its various topologies and significance of ZSI in modern industry. Different PWM techniques are used to obtain wider modulation range and easier real time implementation. This paper provides a systematic reference for future scientists for further development and advancement of ZSI.
文摘This paper presents a modification in pulse width modulation (PWM) scheme with unequal shoot-through distribution for the Z-source inverter (ZSI) which can minimize ripples in the current through the Z-source inductors as well as the voltage across the Z-source capacitors. For the same system parameters, the proposed control technique provides better voltage boost across the Z-source capacitor, DC-link, and also the AC output voltage than the traditional PWM. The ripples in the Z-network elements are found to be reduced by 75 % in the proposed modulation scheme with optimum harmonic profile in the AC output. Since the Zqnetwork requirement will be based on the ripple profile of the elements, the Z-network requirements can be greatly reduced. The effectiveness of the proposed modulation scheme has been simulated in Matlab/Simulink software and the results are validated by the experiment in the laboratory.
文摘This paper presents a single-phase Z-source inverter as a power conditioning system for a single phase utility connected system. Z-source inverter is a single-stage topology that has buck-boost feature, which is possible because of additional shoot through state introduced in zero state of the conventional inverter pulse width modulation and provides desired output AC voltage. Small distributed generation (DG) system with alternate energy sources requires power conditioning units with low cost, high efficiency and tolerance to wide range of input voltage variation and has to perform various functions such as dc-ac conversion, system control and achieve power quality norms. To meet some of these requirements a two-loop control strategy for ac side control with grid current feedback with PI control and inner filter capacitor current feedback with proportional control and on dc side PID control for Z-source capacitor voltage regulation are employed, which gives good transient response also suppress load and source disturbances effectively. Theoretical analysis of proposed scheme is established and then simulation results are presented to validate proposed control strategy.
文摘Quasi Z-source converter is a single stage soft switched power converter derived from Z-source converter topology, employing an impedance network coupling the source with the converter. The quasi Z-source source converter can buck or boost the voltage and current flow is bidirectional. The duty cycle of the switch can be adjusted to maintain constant voltage during load change. To obtain constant output voltage, proper controller design is a must. This paper presents closed loop control of quasi Z-source converter using PI controller where controller parameters are estimated using the small signal model of the entire system. The transfer function of the system with AC sweep is used to obtain appropriate proportional and integral gain constants to reduce transient dynamics and to reduce steady state error.
文摘A new ride through strategy is introduced in a three-level dual Z-source inverter, for isolation under semiconductor switching failure condition. Here the output will have no significant decrease in the amplitude and quality. Instead of diodes, the triacs are added to the inverter source ends, as it can perform a bidirectional power transfer also it can operate well in both low and high voltage operating conditions. The faulted part can be isolated by simply altering the firing pulses for turning on/off the triacs using the carrier based SPWM technique and resulting in a boosting output with zero common mode voltage. Consequently, it forms a common floating point or null point with a zero common mode voltage. It is experimentally verified by using MATLAB, and digital oscilloscope.
文摘文中提出一种新型单级式隔离型模块化多电平级联变换器(isolated modular multilevel cascade converter,I-MMCC),其具有中压三相交流(medium voltage three-phase AC,MVAC_((T-P)))、中压单相交流(medium voltage single phase AC,MVAC_((S-P)))和低压直流(low voltage DC,LVDC)3种电压端口。该变换器可实现从LVDC到MVAC的单级式功率变换,MVAC_((T-P))与MVAC_((S-P))电压端口能够实现同频或变频的AC-AC功率自由变换,其单极性调制策略可避免隔离型AC-AC矩阵变换器双向开关管换流暂态过程中出现的电压尖峰等问题。首先,介绍I-MMCC子模块拓扑结构与调制策略,并建立子模块及单相I-MMCC平均等效数学模型;其次,分析MVAC_((T-P))与MVAC_((S-P))端口变频–变压工作原理、稳态功率与端口特性,对单相交流端口基于正交虚拟电路概念,建立控制模型,并推导出MVAC_((S-P))、MVAC_((T-P))端口功率约束关系。最后,通过搭建一套实验样机验证所提出拓扑结构的有效性和优越性。
文摘电力弹簧(electric spring,ES)作为一种电能质量优化装置,对关键负载与非关键负载进行区分使得电力弹簧在对关键负载进行保护时,非关键负载无法运行在其额定电压下,而且其调压能力受到线路参数的限制。针对传统ES在实际电网中工作时的被动性,文中提出一种基于双极性直接式AC-AC变换器的主动电力弹簧(AC-AC based active electric spring,AC-AES)实现分布式调压。AC-AES不再对关键负载与非关键负载进行区分,对用户负载进行统一控制,从而使其调压变得主动。最后,通过仿真和实验分别验证所提装置通过调节电压调控负载功率的可行性,以及在波动电网中稳定负载电压的能力。