Patent ID: 8994319
Filing Date: 2015-03-31
Classification: H02K,H02P

Abstract:
1. An electric motor comprising: a magnet rotor which is rotatably placed with an air gap interposed between the magnet rotor and a stator around which a driving coil is wound, the magnet rotor having a magnetic pole portion formed from a plastic magnet which swells by a hydrogen bond; an inverter circuit including an upper-stage switching device and a lower-stage switching device which are connected to each other in a bridge manner; a DC-voltage conversion portion which is formed from a chopper circuit adapted to apply a DC voltage to the inverter circuit; a driving logic control portion adapted to supply the DC voltage generated by the DC-voltage conversion portion to the driving coils through the inverter circuit, in a successive full-wave energization manner according to a predetermined direction and in a predetermined order; a supply current value control portion adapted to control an average current supplied to the inverter circuit to be constant; a current value designation portion adapted to designate an average current value for which the supply current value control portion controls to be constant; a reference current value designation portion adapted to set a reference current value to be designated by the current value designation portion, when the DC voltage generated by the DC-voltage conversion portion is a predetermined voltage; and a correlation designation portion adapted to provide the current value designation portion with designation of a correlation between the reference current value and the average current value according to a voltage value of the DC voltage generated by the DC-voltage conversion portion, wherein the correlation designation portion determines the average current value by changing the average current value linearly or non-linearly with respect to the reference current value, and the magnetic pole portion absorbs moisture to swell to make the air gap smaller, at a higher humidity than a reference humidity.