多台电力电子变压器云-边脉宽调制同步控制策略

为提升多台电力电子变压器(Power Electronic Transformer)的高频开关谐波协同控制能力,需实现高精度、高可靠的脉宽调试同步控制。本文提出一种基于“云-边”双重信息的多PET脉宽调制同步策略：在通讯系统正常运行时,PET利用“云”端发送的同步信号实现高精度的脉宽调试同步；当通讯系统故障时,PET可利用“边”端计算结果实现高可靠的脉宽调制同步。因硬件要求低,该策略易于应用。实验证明,该策略能兼顾脉宽调制同步的精度与可靠性,保证高频率开关谐波协同控制。

The cloud-edge signals based PWM synchronization strategy for multi-power electronic transformer

Due to the limited rated power of individual power electronic transformer (PET),many PETs are always connected in parallel in practice. High-order harmonic interactions occur when PETs are in operation,resulting in a rise in the amplitude of the output high-order harmonics. Thereby,the power quality is influenced. The safety of PETs is also threatened by the high-order harmonics. In order to control the switching harmonics among the parallel PETs,a pulse width modulation (PWM) synchronization strategy based on the mixed information which is the combination of cloud signals and edge signals is proposed in this article. The basic idea has two parts. Firstly,the PWM synchronization is realized according to the cloud signals when the communication system works well. Secondly,the realization of PWM synchronization is switched to edge signals during the communication faults. It is proved that the high-precision and high-reliability can be guaranteed by the proposed strategy. The high-order harmonics can be coordinated-controlled well. Doing so,the interaction of high-order harmonics among PETs can be eliminated. The proposed strategy can be easily implemented due to limited requirement of additional hardware. With using the proposed strategy,the power quality and the reliability of PET can be improved.