Huang Wenxin

An improved sliding mode observer for position sensorless vector control drive of PMSM

This paper proposes a position sensorless control scheme for permanent magnet synchronous motor (PMSM) drive using an improved sliding mode observer (SMO). It is more precise than the conventional SMO and also the structure is simple. Compared with traditional SMO, the sign function is replaced by a saturation function, as well as directly differential speed calculation method is replaced by phase-locked loop (PLL). To achieve better filtering effect and simplify the hardware structure, a variable cut-off frequency low-pass filter is designed. The stability condition of EMF based SMO is studied to make sure that the observer is stable in converging to the sliding mode plane. The paper analyzes the structure and performance of the improved SMO strategy with DSP based experiments. Results show that the proposed SMO of PMSM can satisfactorily estimate the position and speed of PMSM.

Direct active and reactive power control of PMSM

A novel control strategy based on the instantaneous power direct control for permanent magnet synchronous machine (PMSM) system is proposed. The control mechanism is firstly analyzed, and the influence of the instantaneous active and reactive power in torque and stator flux-linkage is explained in detail. The strategy of the direct power control by selecting the optimum voltage vector is then presented, through which the active and reactive power errors are restricted in a certain band. That is, improving the power factor at the same active power when the reactive power is controlled to be zero nearly. Both the results of simulation and experiment show the good performance and accuracy of the proposed method. Especially, this method has good application prospect in energy saving motor driven systems.

A novel 6/3-phase dual stator-winding induction generator system applied in wind power generation

The usual dual-stator winding induction generator (DWIG) is composed of three-phase power windings and three-phase control windings, named as 3/3-phase DWIG. The power winding has only three phases, and also connects to a rectifier load, which results in larger harmonic magnetomotive force (MMF) in the generator. In order to overcome these problems, the power winding of 3/3-phase DWIG is converted from three phases to six phases. A novel 6/3-phase DWIG with six-phase power windings and three-phase control windings is proposed. The six-phase power windings of it are divided into two Y windings shifted by 30° electrical angle. In this paper, the control technology of this novel 6/3-phase DWIG system operating on variable speeds is studied. Based on the control winding flux oriented scheme, for a 600 V/18 kW 6/3-phase DWIG system running at variable speeds, a series of simulations and experiments are researched. The results demonstrate that the system has the good performance over a wide speed range of 500~1000 rpm, and it is suitable for the application of wind power generation.

A novel dual stator-winding induction generator system applied in wind power generation

This paper presents a novel usage of 6/3-phase dual stator-winding induction generator (DWIG) with a static excitation power controller (SEC) as a wind power generator. This generator is composed of a standard squirrel-cage rotor and two sets of winding housed in the stator slots. One is referred to as the 6-phase power winding, and the other is defined as the 3-phase control winding. On the basis of the instantaneous power theory, the control mechanism of DWIG wind power system is analysed, and the control winding flux orientation control strategy is obtained consequently. The simulation and experimental results from a prototype of 18 kW 6/3-phase DWIG wind power system are presented to verify the correctness and feasibility of control strategy, and a desirable performance is implemented.