基于傅立叶分析的三相SPWM逆变器死区效应与补偿研究

Research on three-phase SPWM inverter dead-time effect and compensation based on Fourier analysis

为了减少逆变器输出波形所含的谐波分量,降低二极管钳位型三电平逆变器的死区效应对输出电压基波和低次谐波的影响,提出了适用于二极管钳位型三电平逆变器的死区补偿方法。利用傅立叶变换分析了三相SPWM逆变器死区时间影响输出波形谐波分量的机理,在载波的开始和中间分别采样输出电流,根据检测到的输出电流方向调整功率器件的开关动作时刻,最终使得输出电压波形与理论波形一致,达到良好的补偿效果。该方法能有效减小输出谐波含量,并恢复由死区效应引起的有效值损失。通过Matlab仿真,验证了方法的可行性。

In order to reduce the harmonic component contained in inverter output waveform, and decrease tile influence of diode-clamp three-level inverter dead-time effect on the output voltage fundamental wave and low- order harmonic. The dead-time compensation method which applies diode-clamp three-level inverter is proposed. The mechanism which the three-phase SPWM inverter dead-time affects the output waveform harmonie component is analyzed by using Fourier transform. The output current is sampled respectively at the beginning and middle of the carrier. The switch action time of power components is adjusted according to the detected output current direction, making output voltage waveform and theory waveform consistent to achieve good compensation effect. This method can effectively reduce the output harmonic content and restore the effective value loss caused by dead-time. Through the simulation of Matlab, the feasibility of the method is validated.