三相PWM整流器的死区效应分析及补偿方法

Analysis and Compensation of Dead-time Effects in Three-phase PWM Rectifiers

在三相PWM整流器的功率管驱动信号中加入死区时间可防止电压直通,但这会对变换器的电压电流波形产生影响,称之为死区效应。为此,详细描述了死区时间内变换器的工作过程,提出了三相PWM整流器的死区电压效应和电流效应,并分别进行了定量分析。然后结合空间矢量调制策略,引入了死区效应空间矢量的概念,统一并从本质上解释了死区的两种效应。为了克服死区效应的不良影响,提出了两种补偿措施,并详细介绍了利用DSP的数字实现方法,这两种措施均不需要改变硬件电路,也不会增加控制器的复杂度和负担。最后,通过实验验证了理论分析的正确性和补偿措施的有效性,还指明了进一步研究的方向。

To prevent short-circuit in the three-phase PWM rectifiers, dead-time should be inserted into driver signals,which affects current and voltage waveforms of the voltage-source converters, called the dead-time effects. We described the work process of the converters in the dead time,and proposed the current effect and voltage effect of the dead-time for three-phase PWM rectifier, with corresponding quantitative analysis. Combining space vector modulation strategy, the concept of dead-time space vector was introduced to explain the nature of these two deadtime effects. In order to overcome the side-effect of dead-time, two compensation measures were taken, which do not need to change the hardware circuit and would not increase the controller＇s complexity and burdens. The DSP implementations of these two measures are discussed in detail. Finally, the correctness of the theory Of dead-time impact and the effectiveness of compensation measures were experimentally verified.