Papers by Author: Zhang Fei Zhao

Abstract: The mathematical model of three-level PWM rectifier is a multi-input multi-output system of strongly coupled system. In industrial applications, PI controller is adopted as the main regulator of the rectifier, but parameter setting of the PI controller is of great impact on the system. In this paper, we put forward a method of applying LQR algorithm to the controller of the power inner loop, combined with the power mathematical mode of the three-level PWM rectifier. The feasibility and accuracy of the method is verified through the simulation.

Abstract: In this paper, a constant switching frequency direct power control strategy based on the virtual line-flux-linkage oriented system for three-level PWM rectifier using space vector modulation (VF-DPC-SVM) is proposed, which is on the basis of the mathematic model of the PWM rectifier, the instantaneous reactive power and the vector control theory. Compared with the traditional control strategy, the proposed VF-DPC-SVM method guarantees a fixed switching frequency and realizes a better dynamic performance. The simulations and experiments indicate that the system has a better dynamic performance with lower harmonic current by use of the control strategy and can achieve the decoupling control of the active and reactive power.