Research on AC electronic load with dual PWM converter

An AC electronic load with energy feedback function based on dual PWM converters is designed.The first stage PWM converter realizes load characteristic simulation function.The single hysteresis current control (HCC) method is designed,which can simulate the specified impedance of electronic load representing to AC sources.The second stage PWM converter achieves energy feedback function.The voltage and current double closed-loop control for the proposed grid-connected inverter are also designed.The outer loop is DC voltage control,which can control DC input voltage of grid-connected inverter to be stable.The inner loop is grid-connected current control,which can make grid-connected inverter's output current have the same frequency and phase angle with grid voltage,so the unity power factor inverter can be realized.The experimental results show that the designed single HCC control strategy and voltage and current double closed-loop control method are effective,the input port of electronic load can accurately simulate the specified impedance and the testing energy can be fed back with unit power factor.