APOLLO WTC-300 series wind turbine controller is a rectifier which converts three-phase three-wire AC power generated from wind turbine to DC for providing to APOLLO GWT-300 series grid connected inverter. The significant feature is over voltage protection. It suits for permanent magnet generator driven by wind turbines, micro-hydro turbines and more. The controller can receive variable AC voltage and variable frequency (VVVF) and rectifies AC voltage to DC output voltage which the DC output is not over than the set point voltage. If the DC voltage is higher than the set point, the controller will switch to dump the turbine power into the dummy load such as heater and incandescent lamp, etc. The wind turbine controller provides communication interface with dry contacts to control the start and stop the turbine in order to prevent malfunction and other alarm signal and control signal.