机车电源测试用电子负载研究

Research on Electronic Load for Testing Locomotive Power Source

为节约能源和提高测试准确性,针对机车电源出厂测试设计一种能量回馈型交流电子负载。介绍此电子负载主电路拓扑与主要功能,分析起能量传递作用的中间直流母线电容控制要求和谐波产生原因,设计两级PWM变换器控制方案,采用电压外环电流内环双闭环控制结构,基于TMS320F2812DSP搭建系统控制电路。试验结果,表明设计的电子负载能准确模拟各种负载特性并将能量回馈至为被测试机车电源供电的直流供电电源。

In order to save energy and improve test accuracy,an energy-feedback AC electronic load is designed for the factory test of locomotive power supply.The structure and function of its main circuit is introduced and especially the principle of DC link capacitor and its harmonic phenomenon are presented in detail.A separate control strategy for the two stages of PWM converter is put forward,which is based on the classical dual-loop control(voltage loop and current loop).The control system based on TMS320 F2812 DSP controller is designed and used successfully in a prototype of electronic load.The experimental results show that the designed electronic load can simulate various load characteristics approximately and transport the energy feedback to the DC power supply for the locomotive power source.