A motor iron-loss calculation device calculates an iron-loss value of a motor on the basis of a primary frequency and a q-axis current component in a dq-axis rotating coordinate system having a d axis in a rotor magnetic flux direction of the motor.

A motor control device includes a current acquisition unit that acquires a limit current allowed to flow from a battery to a brushless motor, a voltage acquisition unit that acquires a power supply voltage applied from the battery to the brushless motor, and a command current determination unit that determines a d-axis command current and a q-axis command current. The command current determination unit determines the d-axis command current and the q-axis command current based on a power limit circle which is a current characteristic on a d-axis and a q-axis based on an inner product of a voltage vector and a current vector and a voltage limit circle which is a current characteristic on the d-axis and the q-axis based on the power supply voltage and an angular velocity of the brushless motor.

A motor control device includes a current acquisition unit that acquires a limit current allowed to flow from a battery to a brushless motor, a voltage acquisition unit that acquires a power supply voltage applied from the battery to the brushless motor, and a command current determination unit that determines a d-axis command current and a q-axis command current. The command current determination unit determines the d-axis command current and the q-axis command current based on a power limit circle which is a current characteristic on a d-axis and a q-axis based on an inner product of a voltage vector and a current vector and a voltage limit circle which is a current characteristic on the d-axis and the q-axis based on the power supply voltage and an angular velocity of the brushless motor.

A control device for an electric motor includes: an inverter circuit configured to drive a rotor of the electric motor by a result of a comparison between a carrier wave and a voltage command value; and a control circuit configured to determine the voltage command value in every control period by vector control by using a current flowing through the electric motor, and a rotational speed and a position of the rotor. The control circuit is configured to shorten the control period as the rotational speed of the rotor or a modulation factor corresponding to the rotational speed of the rotor increases.

A control device for an electric motor includes: an inverter circuit configured to drive a rotor of the electric motor by a result of a comparison between a carrier wave and a voltage command value; and a control circuit configured to determine the voltage command value in every control period by vector control by using a current flowing through the electric motor, and a rotational speed and a position of the rotor. The control circuit is configured to shorten the control period as the rotational speed of the rotor or a modulation factor corresponding to the rotational speed of the rotor increases.

A control device includes: a current detector that detects rotating electrical machine currents flowing to the rotating electrical machine; a position estimator that estimates a rotor position of the rotating electrical machine based on the rotating electrical machine currents; a controller that calculates drive voltage commands based on the rotating electrical machine currents and information on the rotor position, adds position estimation voltage commands and the drive voltage commands to obtain rotating electrical machine voltage commands. The position estimator extracts position estimation currents included in the rotating electrical machine currents, the position estimation currents being changed according to the position estimation voltage commands, and estimates the rotor position of the rotating electrical machine using a DC component of amplitudes of the position estimation currents extracted, the DC component being not changed according to the rotor position.

A motor control method includes the following steps: adjusting a voltage component of an estimated voltage command to a steady-state voltage value; performing a coordinate axis conversion on another voltage component of the estimated voltage command and the steady-state voltage value, and generating a three-phase excitation current to make a synchronous motor rotate to a rotating position and stop; calculating an estimated current signal; calculating an estimated value of the rotating position and adjusting the another voltage component of the estimated voltage command when determining that the current component is not maintained at a steady-state current value; calculating an effective inductance of the synchronous motor based on the steady-state voltage value, the another voltage component of the estimated voltage command, the steady-state current value, and another current component of the estimated current signal when determining that the current component is maintained at the steady-state current value.

An apparatus according to the aspect of the embodiments includes a phase determiner configured to determine a rotational phase of a rotor, a speed determiner configured to determine a rotational speed of the rotor, a controller having a first control mode for controlling the motor by supplying constant currents to windings, and a discriminator configured to discriminate whether a rotation of the motor is abnormal based on the rotational speed when the rotational speed corresponding to a command speed is equal to or higher than a predetermined value in a state where the controller is controlling the motor in the first control mode. When a signal output from the discriminator indicates that the rotation of the motor is abnormal, the controller stops the motor. When the signal output from the discriminator indicates that the rotation is not abnormal, the controller continues a drive of the motor.

An apparatus according to the aspect of the embodiments includes a phase determiner configured to determine a rotational phase of a rotor, a speed determiner configured to determine a rotational speed of the rotor, a controller having a first control mode for controlling the motor by supplying constant currents to windings, and a discriminator configured to discriminate whether a rotation of the motor is abnormal based on the rotational speed when the rotational speed corresponding to a command speed is equal to or higher than a predetermined value in a state where the controller is controlling the motor in the first control mode. When a signal output from the discriminator indicates that the rotation of the motor is abnormal, the controller stops the motor. When the signal output from the discriminator indicates that the rotation is not abnormal, the controller continues a drive of the motor.

There is provided a motor control device which enables torque ripple suppressing control high in followability by executing direct voltage control. A motor control device includes a voltage command calculation unit 15 which calculates a d-axis voltage command value V.sub.d.sup.ref and a q-axis voltage command value V.sub.q.sup.ref from a d-axis current command value i.sub.d* and a q-axis current command value i.sub.q* of a motor 6, a feed forward command value calculation unit 23 which calculates a qi-axis voltage feed forward command value V.sup.qff* for generating a q-axis current ripple on the basis of spatial harmonic parameters and the frequency characteristics of a motor winding, and a subtraction unit 10 which subtracts the q-axis voltage feed forward command value V.sub.qff* calculated by the feed forward command value calculation unit 23 from the q-axis voltage command value V.sub.q.sup.ref calculated by the voltage command calculation unit 15.