Research And Design Of Voltage Source PWM Rectifier Baced On SVPWM

The conventional rectifier section widely consists of diode-rectifier circuit and phase-control thyristor rectifier, which injects large amounts of harmonics into the power networks and produces much contamination. Improving the power factor of the grid and eliminating the harmonic pollution have become the trend of the technology development of converter. The PWM rectifier can eliminate the harmonic pollution of the grid, not only realizing the unity power factor control, but also achieving the bidirectional transmission of the energy between the AC side and the DC side and sinusoidal alternating current. At the same time, the DC voltage of the converter DC side is adjustable and stable in a certain range. It has become a hotspot in power electronics research area recently.According to the difference of direct current energy storage elements, the PWM rectifier is classified into a voltage source PWM rectifier and a current source PWM rectifier. The voltage source PWM rectifier is always a research emphasis due to a series of advantages, such as simple structure, low loss, convenient control, etc. This paper takes voltage PWM rectifier as the study object, analyzes the principle and topological structure of the PWM rectifier, and derives the mathematical model on the basis of the principle, which based on the three-phase static coordinate system and rotating d-q coordinate system. Establishing the mathematical model is a effective method to study the PWM rectifier and provides the theoretical basis for the study of the control strategy.In this paper, the control strategy being studied is the double closed-loop PI control of the direct current control. The double closed-loop PI control include the outer loop of the DC voltage and the inner loop of the current. The current control is the key part of the control system. The outer loop controls the DC voltage as a constant, and the inner loop controls the current in accordance with the current instruction given by the voltage outer loop, achieving the sine wave current and the unity power factor control. This paper introduces the principles of triangle carrier SPWM, CPS-SPWM, SVPWM, and CPS-SVPWM control algorithm. To study the above the control strategy, build the system model of the voltage PWM rectifier in the MATLAB/Simulink environment, and designing the controller with the corresponding control strategy to finish the simulation experiment. The simulation result can verify the correctness and the effectiveness of the four control algorithm. Choosing SVPWM algorithm with good simulation results and low cost is applied to practical system.At last, the paper introduces the design of the hardware circuit and software of the whole voltage source PWM rectifier control system. This circuit takes the chip TMS320F2812as the controller and chooses the double closed-loop PI control as the control strategy. These circuits include the DSP power supply circuit, the crystal oscillator circuit, the detection circuit of the current and voltage, and the protection circuit.