| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a drive system of an electric motor that has a narrow operating temperature range for protection against overheating in a motor, and that can provide high-accuracy protection from overheating. <P>SOLUTION: A drive system of the electric motor includes a direct-current power supply, an inverter circuit, an electric motor in which a driving current is supplied to each phase coil from the inverter circuit, a temperature-sensitive resistive element provided in the electric motor and connected to a power supply line via a transistor, an overcurrent detection circuit having a comparator circuit that compares a detected temperature of the electric motor, detected by the temperature-sensitive resistive element with a predetermined reference temperature and detects whether the detected temperature is higher than or equal to the reference temperature, and a driving section that individually drives on/off a plurality of switching elements. The driving section controls the on-period of the plurality of switching elements and suppresses the drive current supplied to the electric motor, when the comparator circuit detects that the temperature is higher than or equal to the reference temperature. The transistor is normally turned on. As the detected temperature of the electric motor rises, the transistor transits from on to off. <P>COPYRIGHT: (C)2010,JPO&INPIT |
