Three-phase Pwm Rectifier And Its Control

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. The three-phase PWM voltage source rectifier presented in this paper owns such features as constant output voltage, running under unit power factor and feedback of the power into the power networks. This paper mainly focused on the research of two control strategies on PWM rectifier that are Voltage-Oriented Control(VOC) and Direct Power Control(DPC), and also did some relatively work about the influence of unbalanced power networks on the three-phase PWM rectifier.First of all, the theory of PWM rectifier was introduced in details, which were mainly about the topology and working principles, in other words, constructing the high and low-frequency mathematical model under ABC stationary reference frame, αβ stationary reference frame and dq rotation reference frame. In this paper, it mainly did some research on the three-phase voltage source rectifier, and then decoupled its mathematical model in the dq reference frame. In addition, the hardware system was designed on the basis of TMS320F2812 and IPM module and the parameters design of inductance and capacitance was presented.As regarding to the control techniques on PWM rectifier, the current control was proposed earliest compared to others. In this paper, it presented the indirect and direct current control, introduced space voltage vector-oriented control in the direct current control. Furthermore, it proposed the principal algorithm of the control strategy and established the simulation model. The direct power control was just proposed recently for three-phase PWM rectifier. After introducing the traditional direct power control, this paper presented the problems of that method, proposed the combination of space vector modulation and the DPC, and verified the effectiveness of such control strategy by means of simulation and experiments. Lastly, some research was done on the influence of unbalanced power networks on three-phase voltage source rectifier. Moreover, it analyzed method of the dual current control for suppressing the fluctuation of direct voltage, and proposed how to improve the input and output performance in case of unbalanced power networks.