Papers by Author: Guo Jun Tan

Abstract: According to characteristics of unidirectional flow of energy in permanent magnet wind power system, the paper proposes a two-quadrant three-level converter topology. Combined with method of the optimum tip speed ratio for tracking the maximum wind energy, the generator-side converter uses the double closed-loop control, speed outer loop and stator current inner loop control, whose control objective is to track the given generator speed. Grid-side converter uses the direct power control strategy based on virtual flux-linkage orientation. On the basis of MATLAB simulation platform, the permanent magnet wind power system simulation model was established. The simulation results show that the grid- and generator-side converter can operate with unity power factor, furthermore, verifies that the proposed converter structure is feasible.

Abstract: In this paper, on the basis of the mathematic model of the three-level PWM rectifier, a power feedforward based control strategy is proposed combining with direct power control with space vector modulation (DPC-SVM) control principle. Feedforward control can reduce or even eliminate the impact on the system causing by load disturbance to improve dynamic performance. The simulation results show that the control method makes the system response speed faster and the dynamic performance better, it largely improved the system rectifier capacity against load disturbances.

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.