A low-cost wind generator system with a permanent magnet synchronous generator and diode rectifiers

Abstract

Abstract.A low-cost wind generator system for small-or medium-scale wind generator is proposed. The system consists of a permanent magnet synchronous generator (PMSG) with two sets of the three-phase stator windings, i.e. six-phase stator winding, two three-phase diode rectifiers, a boost chopper, and a three-phase pulse-width modulation (PWM) inverter. Since two sets of three-phase stator windings are spatially shifted by 30 electrical degrees, the system can cancel out the dominant harmonic magnetomotive forces (MMF) produced by the harmonic currents of diode rectifiers. The simulation and experimental results show that the proposed system can significantly reduce the pulsation of the developed torque and the DC current by more than 60 % in comparison with the conventional system consisting of a three-phase PMSG and a three-phase diode rectifier. Therefore, the proposed system can use a smaller smoothing reactor in the boost chopper, so that the lower initial cost can be realized, and it is suitable for small-or medium-scale wind generator systems.

Current source back‐to‐back converter for wind energy conversion systems

“…III. MPPT and grid reactive power controller (16) The relation between the two transformer secondary current (is1 and is2) and dual CSI output current (ii1 and ii2) and dual CSI filter capacitor current (ici1 and ici2) are as following:…”

“…With the use of multiphase machines, rated power of wind generators could be increased, and additional advantages can be obtained, such as reduced pulsating torque and current per-phase compared with three-phase of a similar rated power, lower the dc-link current harmonics, and higher reliability, with the possibility of fault tolerant operation [13][14][15][16]. A comparison between the three-phase PMSG and the dual three-phase based PMSG in WECSs presented in [13,14,16] showed that the proposed WECS reduces the pulsating torque and the dc current ripple by (30%~40%), efficiency increased by 3%, reduced dc-link inductance, and much higher dcvoltage can be produced from the dual diode rectifier (which means lower boost converter losses).…”

PMSGs Solutions for Gearless Wind Conversion Systems with Battery Storage

“…Though the PMSGs for wind turbines are typically equipped with a three-phase winding, several multi-phase variants were analyzed in the last years [6]- [7]. The advantages of a multi-phase PMSG compared to the classical three-phase variant can be summarized as follows: the high currents (in case of large power machines) may be divided among several phases, low harmonic distortion and lower acoustic noise at the same power level, improved efficiency, better stability, higher fault tolerance ability, etc.…”

“…In studies like [6]- [7] six-phase PMSGs are studied in comparison with three-phase ones using simplified circuit models. The numerical results prove the advantages of sixphase PMSG.…”

Modelling and comparative performance analysis of special six-phase and conventional synchronous generators for wind farm application

“…In this particular case, only in [8] was found a direct correlation between the machine in focus and its use in wind farms. This paper, however, deals with a permanent magnetic synchronous generator and the wind network is extremely simplified in its representation.…”