The controller of permanent magnet generator controls the current by using control switch which is installed in between power coil and control coil and switches on and off in switches in order to generate two different voltage and increase the power at very low speed condition of generator. The controller controls the voltage of power coil constantly by adjusting current of flowing in the control switch which the voltage is sensed on the load voltage sensor and the controller control the voltage constantly at very small speed by using power switches furthermore, the controller controls the two kind of voltage in power coils constantly by using control switch and switches in case of the generator having different kind of voltages.