计及寄生电容和纹波电流的电压源型逆变器死区效应与补偿方法

Analysis and compensation of dead-time effect in voltage source inverters considering parasitic capacitance and ripple current

电压源型逆变器中固有的死区效应降低了输出电压的品质。为了精确补偿死区效应,需要建立死区效应导致的逆变器输出电压失真的精确模型。但是,已有死区效应模型没有考虑开关管等效并联电容和电感电流纹波对于死区效应的影响,导致死区补偿结果难以优化。本文通过详细分析和推导,发现寄生电容和纹波电流会影响输出电压的精度,并给出了输出电压误差的精确数学表达式。在此基础上,本文提出一种在线、自适应的死区精确补偿方法。最后,通过仿真和实验证明了本文分析的正确性和死区补偿方法的有效性。

Inherent dead-time effect in voltage source inverters reduces the quality of output voltage. To eliminate the dead-time effect, the accurate mathematical model of error voltage caused by dead-time should be deduced first- ly. However, state-of-the-art works on dead-time compensation do not consider equivalent capacitance of switches and ripple current at the same time, which leads to limited compensation efficacy. This paper finds out that these non-ideal factors have a significant influence on error voltage, and an accurate model of error voltage is thus estab- lished. Based on the analytical model, an online, adaptive compensation scheme is proposed. Experiment results verify the analysis and the validity of the proposed compensation method.