Three-phase Grid-connected Inverter Hysteresis Control Technology

In recent years, the shortage of energy has attracted extensive attention of the international community. In order to alleviate and resolve the major problems of mankind, development and utilization of new energy sources to become one of the hottest research topics in recent years. As the interface of renewable-energy and grid, the control technology of inverter is especially important. Aiming at the shortage that high switching frequency of the commonly used hysteresis control techniques, combined with the concept of voltage space vector, using a stationary coordinate system based on two-phase hysteresis current control, designed a three-phase grid-connected inverter, decrees switching frequency.Three phases inverter which connects to grid must be a current source, the current come out from inverter which need to connect to the grid must be the same phase and frequency with grid. Therefore, the output of the inverter current waveform quality and the dynamic performance of control system need to meet some requests. In this paper, based on the related research literature,after anglicizing a variety of inverter current control methods,some research and simulation were done on hysterics current control method. The traditional theory of hysterics current control method is relatively simple and more convenient to use. As the coupling between the three phases in the three-phase system, in order to get the same quality of waveform with other control methods, the ordinary hysterics current control method need to make some sacrifices in switching frequencies. So the unique concept of voltage space vector is combined with the concept of hysterics current control method in this paper, making the hysterics current control on vector graphic to coordinate the three-phase and reduce the switching frequency.On the three-phase grid-connected inverter platform which is built during the course of the study, some experiments on hysterics current control based on space vector hysterics current control and three-phase coordinates were done, and with meeting the basic criteria of grid-connected, achieved the target of connecting to the grid with the output power is 1 kW.