This paper presents a capacitor-voltage-balancing control scheme for an isolated medium-voltage AC-DC converter using level-shifted pulse width modulation (PWM) control of a modular matrix converter (MMxC). The proposed isolated AC-DC converter is composed of the primary MMxC with level-shifted PWMcontrol, high-frequency transformer, and secondary H-bridge circuits. The high-frequency transformer of the proposed circuit can be downsized because the level-shifted PWM control scheme makes the rated frequency of the high-frequency transformer equal to the switching-frequency. The proposed capacitor-voltage-balancing control can compensate for the capacitor voltage imbalance of the MMxC using the positive-sequence and negative-sequence circulating-currents with a power supply frequency and high-frequency voltage. In the proposed control system, the three feedback control systems with DC control variables can be developed to compensate for the capacitor voltage imbalance. The effectiveness of the proposed capacitor-voltage-balancing control scheme and the control systems is verified by experiments using a 200 V, 5-kW laboratory prototype.

中文翻译：

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隔离中压AC-DC模块化矩阵变换器的电容电压平衡控制

本文提出了一种采用模块化矩阵转换器 (MMxC) 的电平移位脉宽调制 (PWM) 控制的隔离式中压 AC-DC 转换器的电容器电压平衡控制方案。所提出的隔离式 AC-DC 转换器由具有电平移位 PWM 控制的初级 MMxC、高频变压器和次级 H 桥电路组成。由于电平移位 PWM 控制方案使高频变压器的额定频率等于开关频率，因此可以缩小所提出电路的高频变压器的尺寸。所提出的电容器电压平衡控制可以利用电源频率和高频电压的正序和负序循环电流来补偿MMxC的电容器电压不平衡。在所提出的控制系统中，可以开发具有直流控制变量的三个反馈控制系统来补偿电容器电压不平衡。所提出的电容器电压平衡控制方案和控制系统的有效性通过使用 200 V、5 kW 实验室原型的实验得到验证。