开绕组电机共直流母线双逆变器调制策略优化

The Optimization of Modulation Strategy of Dual Inverter With Common DC-link for Open-end Winding Motor

针对双逆变器调制产生的零序电压在共直流电压母线结构时形成的零序电流损害半导体开关器件和开绕组电机绝缘的问题,利用空间电压矢量解耦思想和正态分布原理提出了一种双逆变器零序电压消除和输出电压频谱优化的新方法。该方法在实现过程中无需进行相应的查表和扇区判断,直接利用解耦后的三相给定相电压的瞬时值来计算相应开关管的切换时刻,实现了双逆变器的零序电压瞬时值的消除。同时,利用正态分布原理对有效时间的置放位置进行修正,在不影响零序电压消除效果的前提下,优化了逆变器输出电压的频谱,降低了输出电压谐波含量。仿真和实验验证了所提方法的正确性和有效性。

Aiming at the problem of zero-sequence current produced by dual inverter with common DC link as this configuration system is the presence of high zero-sequence voltage, stressing the semiconductor switching devices and the motor. So in this paper, a novel method about zero-sequence voltage elimination and spectrum optimization of output voltage for dual inverter was proposed by using the space-vector decoupling PWM strategy and normal distribution theory. The corresponding switching times are directly calculated according to the decoupled three phase reference voltages, avoiding the complex sector judgment and table lookup in the implementation process. It can achieve the elimination of instantaneous value of zero-sequence voltage in dual inverter. Based on the normal distribution theory, the placement location of effective time was corrected to achieve the optimization of spectrum for inverter output voltage, reducing the harmonic content of inverter output voltage without having an influence on eliminating instantaneous value of zero-sequence voltage. Simulation and experimental results are given to verify the correctness and validity of the proposed method.