INVESTIGATION OF VOLTAGE RIDE THROUGH PERFORMANCE PMSM BASED WIND TURBINE

Abstract

Over the past few decades, there is a rise in global energy demands, as much energy is produced through conventional fossil fuel-based resources there are major concerns such as global warming, greenhouse gases which led to adversely affected the environment, and climate change. Renewable energy is gaining popularity over non-renewable energy as an alternative, among all wind energy is one of the mature renewable sources. Due to the increased penetration of wind turbines in the power systems, challenges and requirements of low voltage ride through (LVRT) capability is an essential requirement for wind energy conversion systems. In this research work, an extensive literature review of different LVRT capability enhancement methods used for wind turbines is studied, and a review of different grid codes is also studied. The full-rated power back-to-back converter-based Type 4 wind turbine is considered for the study. Indirect vector control for both the machine side converter (MSC) and grid side converter (GSC) is implemented. The MSC control is done with maximum torque per ampere (MTPA) based technique to generate the reference current commands for the inner loop control. The GSC control is done to maintain the DC link voltage and for active power, control using the vector control. Also, speed and pitch control is implemented based on the maximum power point tracking (MPPT) and torque control of the wind turbine. During LVRT, there is a mismatch between generated active power and supplied active power to the grid, which increases the dc-link voltage. So, to overcome the problem of overvoltage in dc-link, a control technique is designed to limit the torque during LVRT events. The torque control algorithm is used to de-load the generator to limit the active power produced by the generator during LVRT. The advantage of this control algorithm is, there is no external hardware support is required. A 2 MW Type 4 wind turbine is considered for the simulation study, which is modelled on the MATLAB/Simulink platform. LVRT event is created by a three-phase symmetrical fault with varying voltage sag levels i.e. 100%, 90%, and 80%. Simulation results show the improvement in the dc-link voltage profile during LVRT events due to the implementation of torque limit control as compared to the conventional control technique.