Voltage control for variable speed wind turbine using buck converter based on PID controller

Currently, energy diversification is needed to overcome the limitations of fossil energy as a fuel for electricity generation. In Indonesia, one source of renewable energy that has great potential is wind energy. Wind energy conversion system is an environmentally friendly electricity generator with unlimited availability. However, the electrical energy produced depends on the fluctuating wind speed so that it produces a fluctuating voltage. Variable speed wind turbine is one of the most widely used wind turbine types because it has better efficiency but requires control to overcome the fluctuations in the voltage generated. This paper presents voltage control on a prototype variable speed wind turbine with a permanent magnet synchronous generator (PMSG) and buck converter. The output voltage generated by the PMSG will be rectified by a three-phase uncontrolled rectifier. Voltage control is done through the duty cycle settings on the buck converter that is connected to the battery for energy storage. PID controller is used to set the duty cycle of PWM pulses with a switching frequency of 31.5 kHz. The Propotional Integrator Differensiator (PID) controller is embedded in the microcontroller. Based on the test results, the resulting output voltage can be held constant at 14V by providing variations in wind speed changes which are simulated through PMSG speed changes. Transient responses with the fastest settling time of 1.2 s were obtained with the PID controller parameter values Kp = 0.6, Ki = 0.15 and Kd = 0.6.