阶梯波合成逆变器的波形调制技术研究

Research on Waveform Modulation Technique for Staircase Inverters

阶梯波合成逆变器开关频率低,谐波含量小,滤波容易,特别适合大功率应用场合,但由于传统阶梯波合成逆变器功率管驱动信号采用延时的方法产生,动态性能差。研究了一种新的阶梯波合成逆变器波形调制技术,采用空间矢量调制方法得到各桥功率管驱动信号,提高逆变器的带宽。在分析移相变压器对空间矢量的影响的基础上,结合阶梯波合成逆变器对驱动信号的逻辑要求,提出从相位滞后通道至相位超前通道顺序采样的错时采样空间矢量调制(space vector modulation,SVM)策略,并分析该调制技术的谐波消除机制和特性。仿真和实验验证了该技术可以用于阶梯波合成逆变器的输出电压的调节,具有优良的输出频谱特性,且增大了逆变器的带宽,有利于提高逆变器的动态性能。

Staircase inverters are suitable for high power applications due to their low switching frequency and perfect harmonic performance. Traditionally delaying method is applied to generate switching signals and inverter＇s dynamic performance is poor. A novel waveform modulation technique for staircase inverters was proposed, which adopted sample-time-staggered space vector modulation （SVM） technique to generate all switching signals and enlarge inverter＇s bandwidth. By analyzing the effects of phase-shifting transformers on basic vectors, a special sample sequence of SVM, which was from lagged bridge to leading one, was introduced to meet the gating signal＇s logic requirements. The output waveform＇s spectrum and the characteristics of this modulation technique were analyzed. Simulation and experimental results show that this technique can be used to regulate the staircase inverter＇s output with excellent output spectrum, and the inverter＇s bandwidth can be extended, which is useful for improving the inverter＇s dynamic performance.