单相逆变器在实际应用时,直流侧输入电压包含2倍于输出频率的纹波.纹波越大输出谐波含量越高.为抑制输入电压纹波的影响,在分析输入电压纹波来源及表现形式的基础上,提出一种根据其幅值与相位补偿开关管导通时间的改进型正弦脉宽调制技术(SPWM).利用调制信号的周期特性,采用循环查表方式简化补偿策略,提高补偿速度.仿真及样机实验表明该调制方法可有效减小输入电压纹波对系统输出谐波的影响,提高输出质量.
In practical application, the DC input voltage of single-phase inverter contains an AC ripple at twice the output frequency. The ripple is larger, the output voltage total harmonic distortion is higher. In order to reject the input voltage ripple, an improved sinusoidal pulse width modulation technique was proposed. This method compensates switch signal with the ripple amplitude and phase, based on the analysis of the source and manifestation of the input voltage ripple. We take advantage of cyclical modulation signal, and adopt cycle lookup algorithms to simplify compensation strategies as well as improve the compensation speed. Simulation and experimentation results in single-stage single-phase inverter demonstrate that the proposed modulation technique is effective.