| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a drive unit that can reduce vibration/noise when starting, and achieve a smooth connection by a sensorless method, when drive-controlling an electromotor for compressors by a sensorless method. <P>SOLUTION: A drive unit 22 includes an inverter main circuit 1 for applying three-phase false AC voltage to an electromotor 21 for driving an electric compressor comprising a refrigerant circuit to drive it, current sensors 6V, 6W for detecting electric current flowing through the electromotor, and a control circuit 23 that performs sensorless drive control of based on the output of the current sensors. The control circuit applies a predetermined starting current that produces a rotating magnetic field to the electromotor to start it, accelerates up to a predetermined connection frequency, and subsequently switches to sensorless drive control, as well as changes the starting current and the connection frequency depending on load of compressor. <P>COPYRIGHT: (C)2008,JPO&INPIT |
