| At present, converter technology has become the key link in the production process in many industries, and most of the deflectors are rectifiers. PWM rectifier has been applied in many industries by its many advantages, such as the stability of output DC voltage, the two-way transmission of power and the unity power factor. But there are still other issues in traditional control methods, such as the heavy harmonic pollution from AC side, the long current loop response time and the large overshoot from output DC side. In this paper, we use PWM rectifier as the main study object, combined with predictive control theory, to explore a new kind of control method to control the PWM rectifier to improve their relative performance in dynamic and static operational aspects.PWM rectifier is divided into voltage type and current type. Firstly, we analyze their working principles according to the two kinds’ of PWM rectifier topology and establish their mathematical models. Secondly, we mainly analyze the basic principles of space vector PWM control and simulate voltage oriented control and direct power control of the three-phase voltage type PWM rectifier. Meanwhile, we analyze the advantages and disadvantages of the two control programs deeply. Then, we design the predictive controller of PWM rectifier based on the inner current decoupling loop, and the improved model predictive control method is applied to the current type PWM rectifier.Finally, we build the model in Matlab/Simulink for simulation experiments and find the relative optimal control effect by adjusting predict length and controller length, and this result is compared with PI controlled rectifier. The comparative results show that the response rate of output DC side based on predictive control PWM rectifier is faster, and the overshoot is smaller. At the same time, this control method has many other advantages, such as unity power factor operation, low distortion rate of AC side and high anti-interference ability. |
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