Design And Research Of The AC Three-Phase Energy Feedback Power Electronic Load

With the technological development of power electronics, more and more power electronic supplies have being applied in every aspects of our society, these power supplies must take some long time aging and electrical properties test before leaving factories for guarantee the reliability in practical applications. The traditional testing method is to adopt the resistors, inductors and diode rectifier equipments as the testing load of those power supplies, but this method has the drawbacks such as high energy consumption, low testing efficiency and so on. If we adopt the power electronic load (PEL) which has being composed by power electronic elements such as IGBT as the testing load for the power supplies, this could not only precisely simulate the characteristics of the loads, but could return the output energy of the being tested power supply to the grid with high efficiency as well.For the AC PEL, there are more energy consumption types than the energy feedback types in both market and some published papers, and even more less papers concerning with the PEL that could simulate the nonlinear load. In addition, the simulated load parameters range is very small in some published papers, while others did not thoroughly research the mathematical model of the IGBT based PEL. Besides, there are also fewer papers concerning with the harmonic suppression for the rectifier part of the power supplies.For the above discussed researching background of the AC PEL, in this thesis, the author designed the control structures and controller's parameters of the load simulation part and energy feedback part of the AC three-phase PEL both in ABC and dq0 coordinate, and analyzed the disturbance rejection performance of the being controlled electrical variables under designed controller. If the rectifying part of the power supply adopts the traditional diode rectifier topology, this rectifier would bring out large amount of harmonics which would contaminate the electro-magnetic environment of the grid, for this problem, the author researched and designed a control strategy named direct grid current control strategy to suppress this sort of harmonics.Through simulation and experiment of the AC three-phase PEL adopting the proposed control strategies under the two different coordinate, the results confirmed the effectiveness of all the proposed control strategies. Under both stationary and rotational coordinate especially the rotational coordinate, the results shows that the PEL has very fast current regulation speed, and relatively low THD and high load property simulation accuracy, Using the direct grid current control strategy, the results show that the PEL not only has the function of harmonic suppression, but these current control strategies have a more better current steady and dynamic response with a minimum electrical sensors used.