Study On Active Power Filter And Dynamic Voltage Restorer Based On One-cycle Control Theory

The harmonious in power systems has become the important reason of effecting electric power quality. It is not only affecting the secure use of electricity for power consume but also is intimidateing safe and economy operation of power systems. The administering methods of the power harmonious have become a important research task. There are more and more research fruits on Active Power Filter (APF). However, the research of control method and control technique of APF is the core problem. The application of one-cycle control technique in active power filter supplies a new method for the control of APF. In this paper, the producing mechanism is researched on harmonic voltages and currents. The idea is brought forward that harmonic voltages come from power sources and harmonic currents is hail from nonlinear loads. And the harmonic voltages and currents will be exchanged in a circuit. It is also discussed that what compensation and control methods should be taken for active power filters. A harmonics detection method is proposed based on the change relation of coordinates between the static system and the revolving system of coordinates. And a new model of harmonic detecting is proposed. The correctness of theory analysis has been verified with simulation results. The problem of one-cycle control for active power filter is proposed based on the analysis of detecting harmonics and the control of active power filter. Afterwards, the theory and technique of one-cycle control are elaborated. The applications of one-cycle control technique in the control areas of active power filter and dynamic voltage restorer are discussed. Some control models are built for active power filter and dynamic voltage restorer. At the same time, some simulations and experiment are done. In chapter 4, some shunt active power filters with one-cycle control are analysed. The control relationship and control models are established. Especially, a control model of one-cycle control of active power filter is proposed for three-phase three-wire systems. The four-legs voltage inverter is employed for the main circuit of active power filter. This shunt active power filter can compensate the harmonics and reactive currents in line. The simulation is done based on the analysis of theory. Some series active power filters with one-cycle control are researched in chapter 5. The one-cycle control relationships and models of some active power filters are discussed. Especially, the one-cycle control models are proposed for one phase and three phase systems respectively. Some simulations are done. The results of simulation proof the validity of theory analysis. One-cycle control technique is used to the control of dynamic voltage restorer first time. For one-phase systems and three-phase systems respectively, the one-cycle control method of dynamic voltage restorer are analyzed and discussed. And the one-cycle control models are established. That one-cycle control is used to dynamic voltage restorer is not only to hew out a new application area for one-cycle control technique, but a new control method is found for dynamic voltage restorer. The simulation is done based on the model built in this section. The results of simulation appeared that one-cycle control method is a good method for the control of dynamic voltage restorer.