Multilevel inverters are gaining popularity in high power applications. This paper proposes a new ladder type structure of cascaded three-phase multilevel inverter with reduced number of power semiconductor devices wh...Multilevel inverters are gaining popularity in high power applications. This paper proposes a new ladder type structure of cascaded three-phase multilevel inverter with reduced number of power semiconductor devices which is used to drive the induction motor. The ultimate aim of the paper is to produce multiple output levels with minimum number of semiconductor devices. This paper uses only 11 switches along with 3 diodes and 4 asymmetrical sources to produce an output voltage of 21 levels. The modulation technique plays a major role in commutation of the switches. Here we implement the multicarrier level shifting pulse width modulation technique to produce the commutation signals for the inverter. The proposed multilevel inverter is used to drive the three-phase induction motor. The mathematical modeling of three-phase induction motor is done using Simulink. Furthermore the PI and fuzzy logic controllers are also used to produce the reference waveform of the level shifting technique which in turn produces the commutation signals of the proposed multilevel converter. The controllers are used to control the speed of the induction motor. The effectiveness of the proposed system is proved with the help of simulation. The simulation is performed in MATLAB/Simulink. From the simulation results, it shows that the proposed multilevel inverter works properly to generate the multilevel output waveform with minimum number of semiconductor devices. The PI and fuzzy logic controller performances are evaluated using the results which indicate that with the help of controllers the harmonics has been reduced and the speed control of induction motor is achieved under different loading conditions.展开更多
针对传统背靠背三电平变换器成本高、体积大、结构复杂等问题,文中提出一种新型双端口三电平变换器拓扑,通过器件复用方式减少开关器件数量,优化系统结构。首先,详细分析所提新型拓扑的工作原理,给出单相桥臂的6种有效开关状态、电流流...针对传统背靠背三电平变换器成本高、体积大、结构复杂等问题,文中提出一种新型双端口三电平变换器拓扑,通过器件复用方式减少开关器件数量,优化系统结构。首先,详细分析所提新型拓扑的工作原理,给出单相桥臂的6种有效开关状态、电流流通路径及对应双端口输出电平,并对各开关器件的电压应力进行分析。其次,研究并设计一种适用于该新型拓扑的载波层叠脉宽调制策略,加入直流偏移量以避免调制波重合产生的影响。然后,进一步分析该策略在同频与异频工作模式下的调制度范围、相角差约束等关键问题,给出各工作模式下直流偏移量选取原则及两端口调制度约束范围。最后,基于DSP-FPGA-Typhoon HIL 402实验平台对不同工作模式进行验证。实验结果表明,在实现所提新型拓扑双端口电压电流稳定输出的前提下,加入直流偏移量的载波层叠脉宽调制策略使得变换器输出的电能质量良好,谐波含量低。展开更多
介绍了一种新的采用两电平级联技术换流器的拓扑结构和工作原理,分析了载波移相正弦脉宽调制(carrier phase shifted-sinusoidal pulse width modulation,CPS-SPWM)在这种新型拓扑结构的应用机理,搭建仿真模型分析了两电平级联基于电压...介绍了一种新的采用两电平级联技术换流器的拓扑结构和工作原理,分析了载波移相正弦脉宽调制(carrier phase shifted-sinusoidal pulse width modulation,CPS-SPWM)在这种新型拓扑结构的应用机理,搭建仿真模型分析了两电平级联基于电压源换流器的高压直流输电(voltage source converter based high voltage direct current transmission,VSC-HVDC)技术的谐波情况,并分析了谐波含量与子模块数的关系。展开更多
文摘Multilevel inverters are gaining popularity in high power applications. This paper proposes a new ladder type structure of cascaded three-phase multilevel inverter with reduced number of power semiconductor devices which is used to drive the induction motor. The ultimate aim of the paper is to produce multiple output levels with minimum number of semiconductor devices. This paper uses only 11 switches along with 3 diodes and 4 asymmetrical sources to produce an output voltage of 21 levels. The modulation technique plays a major role in commutation of the switches. Here we implement the multicarrier level shifting pulse width modulation technique to produce the commutation signals for the inverter. The proposed multilevel inverter is used to drive the three-phase induction motor. The mathematical modeling of three-phase induction motor is done using Simulink. Furthermore the PI and fuzzy logic controllers are also used to produce the reference waveform of the level shifting technique which in turn produces the commutation signals of the proposed multilevel converter. The controllers are used to control the speed of the induction motor. The effectiveness of the proposed system is proved with the help of simulation. The simulation is performed in MATLAB/Simulink. From the simulation results, it shows that the proposed multilevel inverter works properly to generate the multilevel output waveform with minimum number of semiconductor devices. The PI and fuzzy logic controller performances are evaluated using the results which indicate that with the help of controllers the harmonics has been reduced and the speed control of induction motor is achieved under different loading conditions.
文摘针对传统背靠背三电平变换器成本高、体积大、结构复杂等问题,文中提出一种新型双端口三电平变换器拓扑,通过器件复用方式减少开关器件数量,优化系统结构。首先,详细分析所提新型拓扑的工作原理,给出单相桥臂的6种有效开关状态、电流流通路径及对应双端口输出电平,并对各开关器件的电压应力进行分析。其次,研究并设计一种适用于该新型拓扑的载波层叠脉宽调制策略,加入直流偏移量以避免调制波重合产生的影响。然后,进一步分析该策略在同频与异频工作模式下的调制度范围、相角差约束等关键问题,给出各工作模式下直流偏移量选取原则及两端口调制度约束范围。最后,基于DSP-FPGA-Typhoon HIL 402实验平台对不同工作模式进行验证。实验结果表明,在实现所提新型拓扑双端口电压电流稳定输出的前提下,加入直流偏移量的载波层叠脉宽调制策略使得变换器输出的电能质量良好,谐波含量低。
文摘介绍了一种新的采用两电平级联技术换流器的拓扑结构和工作原理,分析了载波移相正弦脉宽调制(carrier phase shifted-sinusoidal pulse width modulation,CPS-SPWM)在这种新型拓扑结构的应用机理,搭建仿真模型分析了两电平级联基于电压源换流器的高压直流输电(voltage source converter based high voltage direct current transmission,VSC-HVDC)技术的谐波情况,并分析了谐波含量与子模块数的关系。
