Research And Design Of Three-Phase And Three-Level SVPWM Rectifier

Compared with the traditional diode rectifier, the PWM rectifier has many advantages such as sinusoidal and low harmonic of grid side current,adjustable power factor, reversibility of energy, DC voltage controlled, and so on, so PWM rectifier is considered to be the focus of the world attention and research.In this papper, the neutral point clamped three-phase and three-level SVPWM rectifier is studied. Based on the research of the model of PWM rectifier circuit, the operation state and control principle were analysised. At the same time, aiming at the topology of neutral point clamped three-phase and three-level rectifier, the principle of main circuit is analyzed in depth. On this basis, mathematical model of the three-level rectifier is established in three-phase static abc coordinate?two-phase static ?? coordinate and two-phase rotating dq coordinate. The theoretical foundation was laid for three-phase and three-level SVPWM rectifier control system design.In this paper, the voltage and current dual closed-loop control system was adopted. The feed-forward decoupling control based on dq coordinate and the predictive current control based on ?? coordinate system were respectively adopted in current loop design. In the feed-forward decoupling control, the independent control of the active current and reactive current was realized through converting AC values to DC values in the three-phase PWM rectifier. While, according to the actual current error, the control system hardware parameters and other load variables, the predictive current control system predict the trend of current error vector in the fixed sampling period. In Matlab/Simulink environment, the three-phase and three-level PWM rectifier control system was built, the simulation results of two kinds of control method are deeply analyzed.Modulation algorithm as the core of the control system played a vital role. In this paper, the SVPWM modulation algorithm based on grid voltage vector oriented was used. On the basis of the modulation principle analysis and combining with gh coordinates transform, seven sections of switching table was designed in which the effect to neutral point was minimal, then the simplification of algorithm was realized.On the basis of the theory mentioned above, the control system is simulated in the Matlab/Simulink, the results of simulation prove the control system has a very quick dynamic response and high steady state accuracy. This topic is based on the dual three-level converter systems. A DSP+CPLD control platform is built. Through experiment, the correctness of the control strategy can be proved. Rectifier rectifier and energy feedback performance and other performance indicators also are verified.And through analyzing and solving the problems met in the debugging process, the indexes of the system performance was further improved.