Research on control strategy of new current-type energy-fed AC electronic load

Abstract

Aiming at the problems of difficult control of traditional voltage-type AC electronic load, poor dynamic response, and large voltage stress of the downstream power devices, a control strategy of current-type energy-fed AC electronic load is proposed. It adopts dual PWM back-to-back structure, and the front load simulator adopts independent dual-loop control of fuzzy PI control DC current and QPR control AC current. The outer loop of the downstream grid-connected inverter realizes the power balance between the front and rear stages of the system by PI control of the error between the given power and the actual power. The inner loop uses the PI+ repeated control method to track the amplitude and phase of the grid-connected current. The comprehensive control strategy is adopted to finally realize the functions of load simulation, energy feed network, and power balance of AC electronic loads. This solution has the advantages of simple controller design and high realizability. Through Matlab/Smiulink simulation and building an experimental platform, the simulation and experimental results verify the correctness of the theory.