对静止式中频电源的谐波分析和抑制方法进行研究,分析了静止式中频电源拓扑结构,在推导了多电平PWM输出电压波形解析表达式的基础上,总结出输出电压边频带谐波分布规律和谐波总畸变率变化规律。分别针对高次谐波和低次谐波采用不同抑制手段的特点,给出了LC滤波器的参数设计方法,并提出利用双闭环多重比例谐振控制器抑制低次谐波的方法,即负载电流内环和负载电压外环均采用多重比例谐振控制器。最后在研制的300 kV.A样机上进行了实验验证,证明了理论分析的正确性和谐波抑制方法的有效性。
The topological structure of static medium-frequency inversion power supply is analyzed for the harmonic analysis and suppression.The distribution of sideband harmonics and the variation law of THD(Total Harmonic Distortion) are summarized based on the deduced expressions of PWM output voltage.A method of LC filter parameter design is proposed for the suppression of high-order harmonics and low-order harmonics respectively.It is proposed to suppress the low-order harmonics with the MDLPR(Multiple DualLoop Proportional-Resonant) controller.Experimental verification is carried out for the prototype of 300 kV.A static medium-frequency inversion power supply and the results show the validity of theoretical analysis and the effectiveness of the proposed method.