基于三相供电电压偏差选取直流电容参数研究

Study of DC capacitor parameter selection based on three-phase power supply voltage deviation

在电压型PWM AC/DC/AC变换中,直流侧储能滤波电容参数的选取是变换器稳定运行的关键因素之一。针对目前直流侧电容选取存在一定的不精确性,分析了AC/DC/AC变换电路稳态时直流电容充放电的原理,对变换器交直流侧电压的关系进行研究,建立了电容纹波电压与三相供电电压偏差之间的数学模型,提出了基于三相供电电压偏差选取直流侧电容参数的方法。分别对单相和三相不可控整流电路提供直流电源时直流侧电容C的合理选取给出了相应的分析和计算,并通过仿真和试验验证了直流储能滤波电容参数确定方法的有效性。

In the voltage type PWM AC/DC/AC conversion, the DC side energy-storage filtering capacitor＇s parame- ter selection is one of the key factors for stable operation of the converter. In view of the certain inaccuracy in the DC capacitor＇s selection, this paper analyzed the principle of the DC side capacitor＇s charge and discharge when the AC/ DC/AC conversion circuit in steady state, and studied the voltage relationship between the DC side and the AC side of the converter. A mathematical model between capacitor ripple voltage and three-phase power supply voltage deviation is established. Thus, the capacitance parameter selection method based on the three-phase power supply voltage devi- ation is proposed. This paper respectively gives the appropriate analysis and calculations of filter capacitance when three phase and single phase uncontrolled rectifier circuit provides dc power. And through simulation and experimental verification of the DC filter capacitor energy storage method verifies the validity of arguments.