The Research Of High Power DC Power System Based On PWM Technique

In recent years, with the development of Power Electronics technology, the electronic equipments have been more prevalent in the various fields. It has brought much convenience for the mankind, meanwhile, it has also brought out more serious effectively pollution. Especially for traditional mode of rectification, such as diode rectification and thyristor rectification by phrase controlling,these high power direct supplies give rise to lots of harmonics which are injected into power grid because of low power factor.PWM rectifier in its true sense is a kind of green power supply, it makes the AC input side current sinusoidal, and power factor close to 1,so it fundamentally solves the problem that traditional mode of rectification leads to effectively pollution. If a DC/DC converter is connected up to PWM rectifier end, DC output voltage range will become wider, which will be more widely used.It is presented in this paper that three-phase voltage-source PWM rectifier and zero-voltage switching(ZVS) full bridge DC/DC converter are analyzed as the research object. Firstly, two distinct topological structures of converters, furthermore, operating principle and control strategy are respectively illustrated. Three-phase voltage-source PWM rectifier is highlightedly analyzed based on mathematical models in static three-phase coordinates, two-phase coordinates and rotary two-phase coordinates. Then control strategy and the design methods of the parameters of the system based on SVPWM and double closed-loop control strategy are provided.Secondly, on that basis of analyzing operating principles of converters, using the MATLAB simulation software, the simulation models of three-phase voltage-source PWM rectifier and zero-voltage switching(ZVS) full bridge DC/DC converter system are established. The results of the simulation show this system has high power factor, and sinusoidal current of AC side, realizing soft switching in the system.Finally, it is presented that an experimental prototype of three-phase voltage-source PWM rectifier is designed based on TMS320F28335 as controller, and the corresponding hardware circuits and software programs are debugged. Experiment results demonstrate that the theory algorithms and design methods for this system are effective.