开关电源谐波分析及抑制方法

Study of the Harmonics of Switching Power Supply

由单相大功率整流器、单相逆变电路高频大功率开关电源的理论分析可知,开关电源在运行时一定会产生大量的谐波成分。为了解决开关电源产生的谐波给电网稳定带来的危害,设计了一种通用的三相无源滤波器装置并安装在系统的谐振点;通过仿真和试验可知,该装置能够滤除开关电源产生的大部分谐波,抑制谐波向电网注入,使各次谐波的含量低于我国制定的标准,该装置不仅能抑制谐波还能够为系统提供无功功率,从而提高系统功率的因素,保证了电网的电能质量和开关电源的稳定性。

In order to improve the electric energy quality of switching power supply through the theoretical analysis on the high frequen- cy large-power rectification and the reverse switch supply theory, we have concluded that the switch supply is the main polluting source of affecting the power energy quality. At the same time, we have obtained that the contents of 3, 5, 7th-fold harmonic components in the switching supply are the highest through the measurement of special harmonics test instrument. Other high-frequency harmonics also exist, but their proportions are rather low, as can be neglected. Therefore, the 3, 5, 7th-fold harmonic components of the switching supply are the major reasons leading to the system polluted. In order to eliminate the pollution of the harmonics produced by the switching supply to power grid and the side-effect to its own control system, this paper designs a general 3-phase passive filter instrument which can not only restrict harmonics, but also improve the power factor of the supply system. The test shows that the method can make the supply system to ideal effect, the contents of all kinds of harmonics become rather lower than the standard constituted by our coun- try, and it also degrades the power harmonics and decreases the alternating current ripples greatly.