开关电源谐波的研究

为了提高开关电源电能质量,通过高频大功率整流和逆变开关电源理论分析可知,开关电源是影响电能质量的主要污染源,同时通过专用谐波测试仪可得,在开关电源中3次、5次、7次谐波的含量最大,其他高次谐波虽然也存在,但是其能量很低,在抑制时可以忽略,因此在开关电源中3次、5次、7次谐波是影响系统污染的主要原因.针对开关电源产生的谐波给电网造成的污染以及影响自身控制系统带来的危害,设计出一个通用的三相无源滤波器装置,该装置不仅能抑制谐波还能够提高系统功率因素.通过试验表明,应用这种方法能达到理想的效果,各次谐波的含量低于我国制定的标准,使电网谐波降低,交流纹波成分减少.

Study on the harmonics of switching power supply

In order to improve the electric energy quality of switching power supply,through the theoretical analysis on the high frequency large-power reetification and the reverse switch supply theory,we conclude that the switch supply is the main polluting source of afffeeting the power energy quality.At the same time, we obtain that the contents of 3,5,7th-fold harmonic,components in the switching supply is highes! 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 eliminating the polllutin the harmonies produced by the switching supply to netwode supply 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 effeet the contents of all kinds of harmonics become rather lower than nation standard,and it also degrades the power harmonics anti decreases the aftemating carrent rippfes greatly.