| Motor experiment is necessary in the teaching of electric machinery, which plays an very important role in cultivating students' practice ability. DC generator is generally used as the load of the motor in the electric machines experiment, but dc electric energy produced by the generator is consumed through variable resistor in heating to adjust the load, which not only wastes enerey, but also isn't convenient in the load adjustment because the variable resistor is stepped. Electricity feedback loading has excellent loading characteristics, which realizes to load in constant torque under normal speed and in constant power above normal speed. Electricity feedback loader can run in four quadrant, besides run of constant torque(load),it realizes run of constant speed (Motor),which is very suitable for the four-quadrant characteristic experiment of motors. Loading-enerey feeds back to Power Grid or driving end in electricity feedback load,which realizes circular utilization of loading-energy, so it satisfies the purpose of power saving.This paper briefly introduces the development status of motor and drive experimental device. Working principle and control strategy of electricity feedback loading system is analysised, the corresponding simulation model is created and simulation study is maded with MATLAB/SIMULINK, reliability of this system is proved in theory. Then the hardware implementation and software development of the system are described in detail. Finally constant torque mode, constant speed mode and enerey feedback effect of DC electricity feedback loading system are studied experimentally, so the correctness of theoretic analysis is examined in practical.Some practical problems are solved in experimental system debug stage, for example, VFD interference, the error eliminating in data acquisition. However, the deal to the problems of the reactive power compensation and harmonic pollution need further analysis and study.
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