一种新型模块化多电平换流器热平衡控制策略的研究

Thermal Balance Control Method of Modular Multilevel Converters

针对模块化多电平换流器(modularmultilevel converter,MMC)运行中各子模块元器件参数不匹配造成的热不平衡现象,提出了一种嵌入在电容电压平衡算法中的热平衡方法,可在电容电压平衡控制的基础上控制子模块(sub-module,SM)之间的热平衡,保证在不改变子模块输出电压波形及波形质量的基础上均衡各子模块之间的温度差,防止子模块中半导体器件由于高温或频繁的温度变化造成老化或损坏。通过仿真平台验证了所提热平衡控制方法在抑制子模块热不平衡问题上的有效性,实现了MMC中不同子模块间的均衡热应力分布。

Aiming at the thermal imbalance caused by the mismatch of component parameters in each sub-module during the operation of the modular multilevel converter(MMC), a thermal balance method embedded in the capacitor voltage balance algorithm is proposed. This method can control the thermal balance between the sub-modules(SM) based on the capacitor voltage balance control. By keeping the output voltage waveform and its quality of the sub-modules, the temperature difference between the sub-modules is balanced In order to prevent the semiconductor devices in the sub-modules from aging or being damaged due to the high temperature or frequent temperature changes. The simulation platform verifies the effectiveness of the proposed thermal balance control method in suppressing the thermal imbalance of the sub-modules, achieving the balanced thermal stress distribution among different sub-modules in MMC.