Design And Implementation Of The General Purpose Electronic Load System

The electronic load system simulates the real load current characteristic by controlling the output current of the test equipment to replace the real load. The existing electronic load test object is single, the function is limited, and the universality is not strong. In this paper, a general purpose electronic load system is designed, which can be used to test the DC, single-phase and three-phase AC equipments, and can achieve a variety of energy processing methods. In this paper, the topology structure and the current tracking control strategies and the energy coordinated control strategies of general electronic load system is studied.In this paper, the general property of the designed electronic load system is reflected in the applicability of a variety of tested equipments, the diversity of load simulated forms, the flexibility of energy processing strategies. Using the two-stage structure, the front stage is responsible for the load current simulation, while the after is responsible for a variety of energy processing. The DC electronic load simulation circuit combined of Buck and cascade-Boost structure. The AC electronic load is multiplexing three-phase bridge PWM rectifier structure. The rear stage system includes a bridge type electric energy feedback inverter unit, a two-stage energy storage unit and an energy dissipation unit.DC current tracking control strategy uses sliding mode control; Single-phase and three-phase alternating current tracking strategy uses the PI control mode based on the two-phase rotating coordinate system, which enhances the applicability of the electronic load control system. Among them, the single-phase AC construct the virtual rotation phasor by using the Hilbert transform, and then the three-phase AC adopts the SVPWM control mode with feed forward decoupling.This paper focuses on electronic load system energy flow and balance of power, to achieve the coordination control between load simulation unit and fed inverter unit, and simplifies the control structure of the system, determines the energy processing coordinated control strategy and pre-start strategy.Finally, using MATLAB/Simulink to verify the feasibility of the project. On the basis of the simulation, the experiment platform of hardware circuit is built, and the simulation of various forms of load current is accomplished through experiments, and the energy is stored, dissipated or feedback at the rear stage.