Research On Digital One-Cycle Control For Single-Phase / Three-Phase Inverter

Inverter technology has been widely applied in areas like AC motor drive control, uninterruptible power supply and new energy development as an important electrical energy conversion technology. One-cycle control (OCC) is a new PWM control technique. It has been broadly applied in inverter control due to such advantages as simple control circuit, good stability and fast response. One-cycle control is almost realized by means of analog circuit at present. The integral time is affected by the device parameters. The digital one-cycle control can combine both advantages of one-cycle control and digital control.The digital one-cycle control technique for single-phase/three-phase inverter is studied on the thesis. Based on the basic principle of one-cycle control, the digital one-cycle control algorithm for single-phase inverter is introduced, and the modeling and simulation verification are depicted as well. Then, the digital one-cycle control algorithm for three-phase inverter is discussed. A bipolar digital one-cycle control algorithm for three-phase inverter is derived on the basis of the bipolar algorithm for single-phase inverter. Based on the over-modulation running state of three-phase inverter using bipolar algorithm, two kinds of improved digital one-cycle control algorithms which can improve the dc voltage utilization efficiency and reduce switching loss are depicted. Simulation verification for these three kinds of digital one-cycle control algorithms is depicted as followed. Finally, the prototype of three-phase full-bride inverter is designed and built for experimental justification. The design methods of hardware circuit and software program are presented. The experimental results justify above theoretical analysis and prove that digital one-cycle control is applicable to the inverter control.