Variable structure sliding mode control and direct torque control of wind power generation system based on the pm synchronous generator

Abstract

This paper presents a Variable Structure Sliding Mode Control (VS-SMC) scheme and Direct Torque Control (DTC) for Wind Farm (WF) based on the Permanent Magnet Synchronous Generator (PMSG). The WF consists of a 3 PMSGs which are connected to a common dc bus system with rectifier. The dc-bus is connected to the electrical network using only one inverter system, a grid-side filter as well as the transformer. The efficiency of the WF can be greatly improved using an appropriate control approach. So, the control strategy uses the technique of DTC to regulate the speeds of PMSGs for Maximum Power Point Tracking (MPPT) mode. Besides, by employing VS-SMC the grid-side inverter is controlled to inject the generated power into the electrical network, to regulate DC-link voltage and to achieve Unity Power Factor. The used control strategies provide an optimal control solution for WF systems based on the PMSG.