Abstract: An electric machine system includes an electric machine, an electric power converter, and a control unit. The electric machine includes a stator that includes coils, and a rotator that includes a magnet and is rotatable with respect to the stator. The electric power converter inputs electric power with respect to the coils of the electric machine. The control unit controls the electric power converter. The control unit includes an output unit and a correction unit. The output unit outputs a control signal for operating the electric power converter to the electric power converter. The correction unit corrects a phase of the control signal that determines input timing of the electric power with respect to the coils of the electric machine. The correction unit corrects the phase so that the magnitude of the electric power approaches an extreme value.

Abstract: The electric machine system includes an electric machine having a rotor and a coil; the power converter that outputs an output current to the coil of the electric machine; and a controller that controls the power converter. The controller includes a signal output unit that outputs a signal for controlling a mode of the output current to the power converter; and an abnormality detection unit that receives an abnormality signal indicating an abnormal situation. The signal output unit outputs a demagnetization control signal to the power converter when the abnormality detection unit receives the abnormality signal. The power converter causes a demagnetization current for a demagnetization magnetic flux that demagnetizes the permanent magnet of the rotor to flow through the coil in response to an input of the demagnetization control signal.