In the medium voltage cascaded converter, the power imbalance problem among the converter modules will result in certain converter modules over-modulated. Reactive power control (RPC) scheme is an effective way to balance the cascaded converters. Many efforts, such as reactive power sharing control and apparent power sharing control have been used to solve the overmodulation issue. This paper investigates an optimization RPC scheme to solve the overmodulation problem by minimizing the total required reactive power. An improved minimum reactive power (IMRP) RPC scheme is presented, the feasible area for the active power imbalance is evaluated and compared with the reactive power sharing control scheme and the apparent power sharing control scheme. Finally, the control scheme is verified on a three-module scaled-down cascaded inverter.

中文翻译：

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级联变流器模块功率不平衡的无功优化控制


在中压级联变流器中，变流器模块之间的功率不平衡问题会导致某些变流器模块过调制。无功功率控制（RPC）方案是平衡级联变流器的有效方法。许多努力，例如无功功率共享控制和视在功率共享控制已被用来解决过调制问题。本文研究了一种优化 RPC 方案，通过最小化所需的总无功功率来解决过调制问题。提出了一种改进的最小无功功率（IMRP）RPC方案，评估了有功功率不平衡的可行区域，并与无功功率共享控制方案和视在功率共享控制方案进行了比较。最后，在三模块缩小级联逆变器上验证了控制方案。