基于同伦算法的多电平逆变器SHEPWM控制技术

Multi-level Inverter SHEPWM Control Technology Based on Homotopy Algorithm

随着逆变技术的发展,特定谐波消除脉宽调制(SHEPWM)技术在逆变器脉宽调制(PWM)控制,尤其是高压大容量多电平逆变器控制方面受到广泛关注。利用同伦算法求解了七电平九个开关角度的消谐模型,分析了利用DSP事件管理器(EV)实现PWM输出时的一些弱点,并提出利用计数器实现对多电平逆变器的SHEPWM控制。实验结果证明了利用同伦算法求解开关角度的正确性和利用计数器得到多电平逆变器SHEPWM控制的各器件脉冲信号的可行性。这对改善多电平逆变器输出电压质量及简化硬件实现具有一定参考意义。

With the development of inverter technology, selective harmonic elimination pulse width modulaiton（SHEPWM） control method draws more and more attention in pulse width modulation （PWM） control of inverters, especially in high capacity multi-level inverters＇ controlling.This paper uses homotopy algorithm to solve the harmonic elinfination model of seven-level inverter with nine angle.The weakness of event manager（EV） in DSP when using to implement the PWM waveform is analyzed.Then, the method that using a counter in DSP to implement the SHEPWM control of multi-level inverter in low frequency is proposed.The experimental results certificate the angles worked out by homotopy algorithm are correct and it＇s feasible to get the pulses of SHEPWM by a DSP counter.This will make a difference in im- proving the quality of output waveform and provide a valuable reference in simplifying the hardware implementation in multi-level inverter.