有源中点箝位型五电平逆变器SHE-MPC研究

Research on the SHE-MPC for Active Neutral-point-clamped 5L Inverter

针对大功率有源中点箝位五电平(5L-ANPC)逆变器的低次谐波和电容电压平衡问题,提出一种基于特定谐波消除脉宽调制(SHEPWM)的模型预测控制(MPC)方法。首先,通过求解特定谐波消除(SHE)方程组得到全调制比下的所有开关角度,并设计目标函数选择其最优开关模式,实现SHE;然后,采用MPC方法,通过设计成本函数选择最佳开关状态,减小整体开关频率的同时实现电容电压和中点电位的平衡。硬件在环(HIL)实验结果验证了理论分析的正确性及控制策略的有效性。

Aiming at the problems of low-order harmonics and capacitor voltage balance in high-power active neutralpoint-clamped five-level(5L-ANPC)inverters,a model predictive control(MPC)method based on selective harmonic elimination pulse width modulation(SHEPWM)is proposed.Firstly,all switching angles under full modulation ratio range are obtained by solving the unified selective harmonic elimination(SHE)equations,and the objective function is designed to select the optimal switching mode to achieve SHE.Then,the MPC method is used to select the best switching state by designing the cost function,so as to reduce the overall switching frequency and achieve the balance of the capacitor voltage and the neutral point potential.The hardware in loop(HIL)experimental results verify the correctness of the theoretical analysis and the effectiveness of the control strategy.