Research On Techniques Of PWM Rectification

The conventional rectifier produce harmonic problem in power system. While three-phase pulse width modulation (PWM) rectifier can provide alterable dc bus voltage,get unity power factor and get low harmonic distortion of input current. So it is becoming interested in power electronics field. It also has line power feedback capability; As a result it can works at every quadrant, being an ideal choice of designing excitation power and adjustable DC power.With the development of large-scale integrate circuit technology and computer technology, microcomputer-based rectifier controller will become the main stream of rectifier controllers in the future. Constant improvement in rectifier control method set an even higher requirement for the computation of the microcomputer-based rectifier controller. According to this requirement, the paper studies and designs the rectifier controller by using DSP (Digital Signal Processor) as the control center.This thesis mainly introduces PWM rectifier, including its topology, mathematical model, control strategies, the design and choice of the main circuit parameters and its hardware. The mathematical model of voltage source rectifier is essential means to investigate it. It deals with the design of the DSP-based rectifier's hardware and the flowchart and realization method of its software from the aspects of control circuit, driving circuit,measuring circuit, main circuit and the method of realizing SPWM.Besides, the simulation model with closed loop control is set up in dq rotary coordinate while the simulation of PWM rectifier and the conventional rectifier has been done in the circumstance of Simulink. Via the compare of these two models, the advantage of the PWM rectifier is proved.Based on studied the control strategy and the control arithmetic, the program is given and experiment platform is set up run. The experimental results show that every function of the PWM rectifier is according with the original design need.