Motor control apparatus, motor control program, and motor control method

A non-transitory computer readable medium storing a motor control program executed by an arithmetic unit of a motor control apparatus for feedback-controlling a motor comprising the arithmetic unit for executing a program and a current measurement unit for measuring, as measured current values, at least two current values of three-phase AC currents that drive the motor, the motor control program executing:

• current estimation processing that outputs a detected current value corresponding to each of the three-phase AC currents based on the measured current values and a rotor rotation angle of the motor, wherein the current estimation processing includes:
• for each phase of the three-phase AC currents, calculating a coefficient value by dividing the measured current value obtained by the current measurement unit in a period in which a duty ratio of a driving pulse is lower than an operation switching threshold by a value of the rotor rotation angle of the motor at the time when the measured current value is measured;
• for each phase of the three-phase AC currents, updating the coefficient value each time the measured current value is input in the period in which the duty ratio of the driving pulse is lower than the operation switching threshold;
• defining a phase whose duty ratio of a driving pulse supplied to an inverter circuit, which generates the three-phase AC currents, becomes more than or equal to the operation switching threshold as an estimation target phase;
• calculating, for the estimation target phase, an estimated current value based on the coefficient value and the rotor rotation angle of the motor;
• and
• outputting the calculated estimated current value as the detected current value of the estimation target phase.

A motor control method of a motor control apparatus comprising a current measurement unit for measuring, as measured current values, at least two current values of three-phase AC currents to be supplied to a motor and a current estimation unit for outputting a detected current value corresponding to each of the three-phase AC currents based on the measured current values and a rotor rotation angle of the motor, the motor control method comprising:

• for each phase of the three-phase AC currents, calculating, via the current estimation unit, a coefficient value by dividing the measured current value obtained by the current measurement unit in a period in which a duty ratio of a driving pulse is lower than an operation switching threshold by a value of the rotor rotation angle of the motor at the time when the measured current value is measured;
• for each phase of the three-phase AC currents, updating, via the current estimation unit, the coefficient value each time the measured current value is input in the period in which the duty ratio of the driving pulse is lower than the operation switching threshold
• defining, via the current estimation unit, a phase whose duty ratio of a driving pulse supplied to an inverter circuit, which generates the three-phase AC currents, becomes more than or equal to the operation switching threshold as an estimation target phase;
• calculating, via the current estimation unit and for the estimation target phase, an estimated current value based on the coefficient value and the rotor rotation angle of the motor;
• and
• outputting, via the current estimation unit, the calculated estimated current value as the detected current value of the estimation target phase.