| 摘要 |
PROBLEM TO BE SOLVED: To provide an overcurrent detection apparatus detecting overcurrent without providing a shunt resistor upstream of an inverter circuit, and allowing for a small wiring board.SOLUTION: The overcurrent detection apparatus calculates a current value of a power supply line 20 from phase current supplied to an electric motor 1 and a power supply voltage of an inverter circuit 2, and detects overcurrent based on a current value obtained from a drop voltage value generated by an electronic component 5 connected to the power supply line and on the current value of the power supply line. Variations in the ohmic value and changes in characteristics of the electronic component are calibrated based on the current value of the power supply line calculated from the phase current and the power supply voltage. An electronic component for drive control device provided on the power supply line of the inverter circuit is used for detecting the drop voltage value, which allows overcurrent detection without providing a shunt resistor upstream of the inverter circuit. This reduces a mounting area and a wiring area, thereby allowing a smaller wiring board. |
