| 摘要 |
PURPOSE: A motor drive device, a fluid compression system, and an air conditioner prevent the demagnetization of a permanent magnet by changing an over-current protection stop threshold value to less than a demagnetization current value. CONSTITUTION: An inverter circuit (11) converts a DC voltage to an AC voltage. A current detector (20) detects DC supplied to the inverter circuit. A control device controls the on and off of a switching device. The processing of a device short-circuit protection device (12) is performed without starting a microcomputer. The processing of the control device is performed by starting the microcomputer. [Reference numerals] (10) Power module; (100) Motor driving device; (11) Inverter circuit; (12) Device short-circuit protection device; (13) Inverter driving circuit; (20) Current detector; (30) Amplifier; (300) Converter circuit; (40) Inverter control device; (41) Motor current reproduction unit; (42) Speed instruction unit; (43) Overcurrent determination unit; (44) Driving signal generation unit; (AA) PWM signal |
