高精度大电流电容器纹波测试专用高频电源

A Special High Frequency Power Supply for High Precision and Large Current Capacitor Ripple Test

电容器在电力电子电路中起着滤波、储能等作用,是电力电子电路中必不可少的器件,也是电力电子设备可靠性的重要保证。因此,对电容器的性能进行测试非常重要。根据电容器的纹波测试要求,设计了一种以Buck斩波电路和单相逆变器构成的调压调频电容测试主电路,采用了3个单相逆变器并联实现大电流输出,给出了梯形电流波形计算方法,提出了一种改进高频电流采样的有效值计算方法,并基于FPGA实现了高频脉宽调制(PWM)发波及采样中断信号产生。实验研究所搭建的测试平台最大输出电流可达500 A,频率范围10~20 kHz,具有大电流、高精度、高频及低损耗的特点,基于该测试平台,验证了所提方法的有效性及正确性。

Capacitors play a role of filtering and energy storage in power electronic circuits.They are indispensable de vices in power electronic circuits and guarantee the reliability of power electronic devices.Therefore, it is very impor tant to test the performance of capacitors.According to the requirement of capacitor ripple test, a voltage and frequen cy modulation main circuit composed of Buck chopper circuit and single-phase inverter is designed.Three inverters are connected in parallel to realize high current output.The calculating method of trapezoidal current waveform is giv en ,and an effective value calculating method for improving high frequency current sampling is proposed. Based on the FPGA , the generation of high frequency pulse width modulation (PWM) waveform and sampling interrupt signal is re alized. The maximum output current of the test platform built by the experimental institute can reach 500 A and the frequency range is 10-20 kHz.It has the characteristics of high current, high precision, high frequency and low loss. Based on the test platform, the validity and correctness of the proposed method are verified.