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
针对新能源并网的主动支撑应用需求问题,选取三相全桥AC-DC变换器加双有源桥(dual active bridge,DAB)变换器的两级式结构作为研究对象。在器件寄生电容的影响下,DAB变换器会面临软开关难以实现的问题;且在宽电压范围应用场合下,传统的...针对新能源并网的主动支撑应用需求问题,选取三相全桥AC-DC变换器加双有源桥(dual active bridge,DAB)变换器的两级式结构作为研究对象。在器件寄生电容的影响下,DAB变换器会面临软开关难以实现的问题;且在宽电压范围应用场合下,传统的拓展移相(extend phase shift,EPS)控制在远离单位电压增益点时会带来较大无功环流问题。因此,提出一种拓扑结构及其调制方法,通过添加激磁电感来注入额外的激磁电流,从而保证DAB变换器的全负载范围软开关实现,同时通过对传统EPS控制进行改进,保证宽电压范围下的高效率传能。最后搭建一个20 kW全SiC器件的实验样机,对装置进行稳态测试及软开关性能测试,验证了所提方法的有效性。展开更多
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.
