Research On The Control System In The Inverter Of High Power AC Electronic Load

Power supply products are required before entering the market in accordance with industry products standards and necessary load testing and inspection to ensure the quality and performance. Traditional detection methods are by the physical loads of resistors, capacitors, inductors, and combinations of them. Because the physical loads not only have larger volume and occupy a larger space; the automation is in low degree. What’s worse, they can not simulate a constant voltage, constant current, constant power and other loads with special needs; what most regrettable is that in the final energy from the power source turn into heat, which is a waste of energy.Under the background of the energy depletion of world total of energy and consumption growth, it is necessary to develop new energy sources and use energy efficiently and comprehensively. Power electronic loads which can return energy to the grid come into being. They can not only accurately simulate the load with a variety of flexible electrical characteristics but also they can return energy to the grid, to a large extent which can reduce the economic costs of the test.For the power electronic load with back to back power AC PWM control topology, on the inverter connected to the grid is focused on. To solve the problem of distortion of current connected to the grid and the shortage of distribution of frequency band in current loop by bus voltage fluctuations. Based on previous research band-pass regulator is set in current loop, the combination of linear constant disturbance observer and BP regulator control strategy is proposed. The following preliminary results have been achieved: 1) By research on the development background of electronic load in domestic andforeign countries, several common circuit topologies have been analyzed and theback-to-back circuit topology is conformed. 2) Several control schemes in rectifier and inverter side have been analyzed, on thefoundation of the advantages over the existing control schemes, for the specificfeatures of electronic load, the inverter side combination of band pass regulator anddisturbance observer control strategy is proposed. 3) For the inverter control side, in the control system hardware circuit and softwareprograms have been designed. Because disturbance observer almost depends on thesoftware system implementation instead of the hardware circuit, so softwareprogramming is the key to control. 4) Digital control system based on ARM has been designed, including the discretizationof disturbance observer, BP regulator in inner loop and voltage regulator in outer loop.And the structures and flow charts of software design are shown in this paper.Simulation and experimental results have verified the main conclusions from theanalysis and research, which shows simulation and experimental results are consistentwith the theoretical analysis and demonstrate the feasibility of the control strategy andcorrectness of design for the circuit topology and control system proposed and used in this paper.