CLC型PWM逆变器端无源滤波器的设计

由于PWM逆变器输出电压中含有较多的高频分量,所以逆变器输出端必须加入低通滤波器来减小谐波含量。借鉴在PWM逆变器与电机之间插入共模变压器来消除逆变器输出端共模电压的方法,通过分析共模变压器带有漏感时的等效电路,提出了一种新型的CLC型逆变器端无源滤波器。利用共模变压器产生的漏感代替差模电感来抑制差模电压dv/dt,同时该滤波器对共模电压也有着很好的抑制作用。与传统滤波器相比,该滤波器可通过1个共模变压器同时对共模及差模电压dv/dt起到抑制作用,减少了滤波器的体积规模。最后,仿真和实验结果验证了该滤波器的有效性。

Design of CLC-type PWM Inverter Passive Filter

Since the output voltage of a PWM inverter contains more high-frequency components, a low-pass filter must be added to its output terminal to reduce the harmonic content. By referring to the method in which a common-mode (CM) transformer is inserted between the PWM inverter and a motor to eliminate the CM voltage output from the inverter, the equivalent circuit of the CM transformer with leakage inductance is analyzed, and a novel CLC-type inverter passive filter is put forward. The differential-mode voltage (dv/dt) is suppressed by the leakage inductance generated by the CM transformer instead of the differential-mode inductor. Meanwhile, this filter also has a satisfying inhibitory effect on the CM voltage. Compared with the traditional filter, it can suppress both the CM and differential-mode voltage (dv/dt) through one CM transformer, thereby reducing its size. Simulation and experimental results verified the effectiveness of the proposed filter.