基于混频调制的电力电子变压器设计方法及实验验证

Design Method and Experimental Verification of Power Electronic Transformer Based on Mixed-frequency Modulation

现有的电力电子变压器中电能变换级数较多,导致其效率低、成本高,限制了其应用。基于混频调制策略的三级型电力电子变压器可减少电能变换级数,并可通过合适的控制策略实现双向功率变换和多端口输出。文中对基于混频调制的三级型电力电子变压器的工作原理、控制策略、设计方法及实验验证进行了详细的分析研究,提出了一种单相结构的三级型电力电子变压器,同时引入一个额外的全桥补偿子模块以消除该电路在交流电网中产生的中频谐波电流。最后,搭建交流电压为150 V、直流电压为100 V、功率为1 kW的样机平台,进一步验证了所提单相三级型电力电子变压器方案的可行性。

For existing power electronic transformers(PETs),multiple power conversion stages result in low efficiency and high cost,which limits the application of PETs.The three-stage PET based on the mixed-frequency modulation strategy can reduce the power conversion stages and realize bidirectional power conversion and multi-port output with suitable control strategy.The working principle,control strategy,design method and experimental verification of the three-stage PET based on the mixedfrequency modulation strategy are analyzed and studied in detail.A single-phase three-stage PET based on the mixed-frequency modulation strategy is proposed.Meanwhile,an extra full-bridge compensation submodule is introduced to offset the mediumfrequency harmonic current generated by the circuit in the AC grid.Finally,a prototype platform with AC voltage of 150 V,DC current of 100 V and power of 1 kW is established,and it further verifies the feasibility of the proposed single-phase three-stage PET scheme.