Study On Three-phase AC Power Electronic Load

With the rapid development of power technology,the power industry has been widely promoted.The quality of power supply has directly restricted people's production and life.All kinds of power supplies need to carry out various performance tests before leaving the factory to check their performance and quality.The traditional method of testing is to test energy consumption by connecting the power and the real load,and it has many defects,such as high energy consumption and hard to adjust.Therefore,the power electronic load arises at the historic moment.By controlling the actual output current of the power supply,it can simulate the port characteristics of the load and return the test energy to the power grid,which not only realizes the simulated load function,but also realizes the energy feedback function.Nowadays,the DC power electronic load has been relatively mature,and there are a lot of mature products.But the AC power electronic load is still in the initial stage,and all of them are single-phase AC power electronic load.This paper has studied a three-phase AC power electronic load for the three-phase AC power supply.First,determined its overall structure.The three-phase PWM rectifier is used as the load simulation converter at the front stage to realize the simulated load function.The later stage uses three-phase PWM inverter as the energy feedback converter to realize the energy feedback function.The control strategy is designed respectively.The front stage adopts the improved repetitive control which combines the PI control and the repetitive control,and the later stage adopts the classic double closed loop control.Secondly,builted a three-phase AC power electronic load simulation model by Simulink simulation platform,and verified its functional characteristics.And the load simulation effect of PI control and improved repetitive control is compared and analyzed,which proves the superiority of the improved repetitive control strategy.Finally,designed the detection,conditioning and driving circuit,and designed the corresponding software program using DSP2812,builted an experimental platform of three-phase AC power electronic load system,the simulated load and energy feedback function was tested,and the experimental results were analyzed and verified the correctness of the design and feasibility.