Motor drive apparatus and discharge control method of the same

摘要

An object is to perform discharge of a capacitor using a motor without rotating the motor even when connected to a position sensorless motor. The motor drive apparatus calculates a voltage pulse width at which a motor does not rotate or vibrate using a both-end voltage of a smoothing capacitor and an inductance estimation value of the motor, and applies a voltage with the voltage pulse width to the motor to calculate an inductance. Then, a rotor position is estimated using the inductances calculated for individual switching patterns. A motor current is caused to flow on the basis of the estimated rotor position to perform discharge of charge accumulated in the smoothing capacitor.

主权项

1. A motor drive apparatus comprising:
an inverter that converts DC power into three-phase AC power to be supplied to a motor; a capacitor provided on an input side of the inverter; a control apparatus that controls the inverter; and a current sensor that detects a motor current, wherein the control apparatus includes a rotor position estimation unit that estimates a rotor position of the motor after operation of the motor is stopped, and a discharge control unit that discharges charge accumulated in the capacitor on the basis of the estimated rotor position, and the rotor position estimation unit includes a pulse width calculation unit that calculates a voltage pulse width at which the motor does not rotate or vibrate using a measurement value of a both-end voltage of the capacitor and an inductance estimation value of the motor, for each of three preset switching patterns, an inductance calculation unit that applies a voltage with the voltage pulse width calculated by the pulse width calculation unit to calculate an inductance, for each of the switching patterns, and a position estimation unit that estimates the rotor position using the inductances for the respective switching patterns calculated by the inductance calculation unit.