Accurate MRAS Embedded Minimum Copper-Loss Based Controller for WRIG Coupled With Variable Speed Wind Turbine

Abstract

Sensorless control of the wound rotor induction generator (WRIG) using the model reference adaptive system (MRAS) technique is an attractive option in wind energy generation schemes. However, the accuracy of MRAS under variable wind speed situations is a major issue as the rotor current of the WRIG continuously changes. To address this issue, in this paper, a simple MRAS model has been developed considering the air-gap reactive power of the WRIG as the adaptable variable for the computation of the WRIG rotor position. The accuracy of the proposed model is comparatively high and almost insensitive to the machine parameter variation of the generator. The maximum rotor position estimation error is found to be 0.009 (rad.) for a 50% variation of the magnetizing inductance of the WRIG. Thus, the model is comparatively reliable. Also, the optimized efficiency operation of the WRIG is another major issue in terms of maintenance cost and life expectancy of the WRIG. Therefore, to address this issue, a minimum copper-loss-based control technique has been developed and presented in this paper for rotor side converter control (RSC) of the WRIG. It has been observed that the proposed control technique improves by 1% efficiency in comparison to similar types of other controllers. The proposed MRAS model has been embedded with the proposed RSC controller to improve the accuracy in control and the efficiency of the wind energy generation system. The proposed system is implemented with appropriate simulations and hardware using a wound rotor induction machine of 2.5kW, and a dSPACE CP1104 modulation device, which produces acceptable results.

Keywords

• Model reference adaptive system
• optimum efficiency
• sensorless control
• wound rotor induction generator