电压源逆变器模型预测共模电压尖峰抑制方法

MODEL PREDICTIVE COMMON-MODE VOLTAGE SPIKE SUPPRESSION METHOD FOR VOLTAGE SOURCE INVERTER

模型预测控制可用于实现电压源逆变器的共模电压抑制,然而,死区会导致共模电压产生±udc/2的电压尖峰。针对该问题,详细分析共模电压尖峰的产生机理,并总结出所有会产生共模电压尖峰的电压矢量切换组合。基于该分析结果,提出一种改进的电压源逆变器模型预测共模电压尖峰抑制方法。该方法首先将三相电流划分为7个扇区,以解决电流过零点难以判断的问题,并根据电流扇区设计不同的电压矢量预选方法,以消除死区的影响。其次,还分析电流一拍滞后对共模电压尖峰的影响,并进一步设计了延时补偿策略。仿真和实验结果表明,所提方法可完全消除共模电压尖峰,将共模电压完全限制在±udc/6之间,并可减小电流的总谐波畸变率。

Model predictive control can be adopted to achieve common-mode voltage(CMV)reduction for voltage source inverter(VSI). However,dead time can lead to CMV spikes around ± udc/2. For this problem,the occurrence mechanisms of CMV spikes are analyzed in detail,and all the voltage vector(VV)switching combinations that can generate CMV spikes are summarized. Based on these results,an improved model predictive CMV spikes suppression method for VSI is proposed. First,the proposed method divides the three-phase current into seven sectors to overcome the difficulty in determining the current’s zero crossing point. And different VV preselection methods are designed to eliminate the effect of dead time based on the current sector. Second,the influence of the current one step delay on the CMV spikes is analyzed. And a delay compensation strategy is further designed. Simulation and experimental results show that the proposed method can completely eliminate the CMV spikes with the CMV restricted within ±udc/6,and reduce the current total harmonic distortion.