Research On Three-phase Voltage-type PWM Rectifier Technology

Rectifier caused grid serious "pollution" due to general links of rectifier used non-controllable rectifier or phase-controlled rectifier mode. With "green energy" being proposed, people started to do lots of research work in rectifier which is the major power "pollution" source, and the PWM technology was introduced to the rectifier which achieved sinusoidal current waveform in rectifier's AC-side and could be run at unity power factor, that is, PWM rectifier.Firstly, the research background and the status of PWM rectifier are introduced in this dissertation, and gave the purpose, significance and main content of this research. Through the main circuit topology of the description and analysis of the three-phase voltage-type PWM rectifier, the three-phase half-bridge voltage-type PWM rectifier was made as this object of study, and then the main circuit mathematical model in the three-phase static (a, b, c) coordinates and two-phase (d, q) rotating coordinates would be deduced. Using SVPWM (space voltage vector pulse-width modulation) technology which combined with voltage, current double closed-loop decoupling control strategy, the current decoupling control based on three-phase SVPWM voltage-type PWM rectifier was implemented.Secondly, the three-phase voltage-type PWM rectifier control system is completed based on the theoretical analysis. Hardware design includes the design of the main circuit in the AC-side inductance, the DC-side capacitor and the selection of power switch; the choice of the master chip in the control circuit, and the design of the AC voltage and current sensing circuit, drive circuit and protection circuit. Software design includes the design of the main program and software PLL, the design of first-order digital filter software and software implementation of SVPWM.Finally, conducted the simulation model in MATLAB/Simulink simulation software for three-phase voltage-type PWM rectifiers to study the power of 6kW three-phase voltage-type PWM rectifier control system and get the results; set up three-phase voltage-type PWM rectifier hardware experimental platform to conduct experimental research which got experimental waveforms.Through the research of the simulation and experimental waveforms, the results showed that the three-phase voltage-type PWM rectifier had the power higher factor, DC voltage stability, better steady-state and dynamic performance.