A method for maintaining a detected absolute position of an electric motor operating as an actuator during a critical operation involves the electric motor (2) being controlled by a controller (1) which is supplied with energy from an energy source. In the method, with which an absolute value sensor can be omitted, the absolute position of the electric motor (2) is measured during the operation thereof, wherein rotations of the electric motor (2) are detected. The rotations are counted, and a count value is output to a microprocessor (3) of the controller (1) in order to actuate the electric motor (2), and in the event of a critical operation, the currently detected count value is maintained by means of an independent voltage supply (7).

An electric vehicle propulsion control device includes a power converter that applies an alternating-current voltage to an induction machine and a controller that controls the power converter based on an external operation command. The controller includes a first calculation unit. The first calculation unit calculates, from current information (id and iq) detected at the induction machine and current command values (id*1 and iq*1) that are based on the operation command, a d-axis voltage command (Vd*1) and a q-axis voltage command (Vq*1) for the power converter, and a primary magnetic flux ds and a secondary magnetic flux dr of the induction machine. The first calculation unit also adds to or subtracts from a term including the q-axis voltage command (Vq*1) an interference term stemming from the d-axis voltage command (Vd*1) in calculating a first speed 1 that is a free-run speed of the induction machine.

A rotary machine control apparatus includes: a current detector detecting an alternating current flowing through a rotary machine and outputting a current detection value; a power converter supplying power to the rotary machine by applying an AC voltage based on a voltage command value; a current controller adjusting the voltage command value so that the current detection value matches a current command value; an estimator obtaining a magnetic-flux estimation value that is an estimation value of an amplitude of a magnetic flux vector in the rotary machine; and a magnetic flux controller adjusting the current command value so that the magnetic-flux estimation value matches a set magnetic-flux command value in a start-up control period from when the rotary machine is put in a state where the rotary machine rotates by inertia after interruption of power supply of the power converter until the power supply is resumed.

A power tool includes an operating switch; a motor that is connected to the operating switch and capable of starting in response to the conduction of the operating switch and braking in response to the disconnection of the operating switch; and a control circuit configured to control a working state of the motor. The control circuit includes a driver circuit including multiple switching elements; a controller that is coupled to the motor and capable of outputting a first control signal to control the motor to start; and a parameter detection unit for detecting a working parameter of the motor. The controller is configured to, in response to the operating switch being turned on again within a preset time after being turned off, acquire the working parameter and set a duty cycle of a second control signal according to the working parameter to control the motor to restart.

A control apparatus controls rotating electrical machine which is applied to a vehicle in which an engine is automatically stopped in the case where predetermined automatic stop conditions are satisfied, and, the engine is automatically restarted in the case where predetermined restarting conditions are satisfied, the rotating electrical machine receiving supply of an exciting current from a transistor-chopper type exciting circuit in which a first pair of facing arms of a bridge circuit is configured with power transistors, and a second pair of arms is configured with diodes, and the rotating electrical machine having a power generation function based on rotational force of the engine. The control apparatus executes first grounding control in which, during automatic stop of the engine, among the first pair of arms, the power transistor connected on an earth side of the rotating electrical machine is put into an ON state.

When a rotation start position of a rotation shaft 132 is a middle start position 31a (i.e., when rotation of the rotation shaft 132 is stopped in the middle and the rotation is restarted), target rotational speed (relative target rotational speed) is defined using a relative pattern 31 that uses the middle start position 31a as a reference, without using an absolute pattern 33 that is defined using a normal rotation start position 33a as a reference. Upon detecting that a condition that absolute target rotational speed corresponding to an angular position detected by a rotation sensor 134 is greater than the relative target rotational speed is not satisfied, motor control is switched so that the absolute pattern 33 is used.

Provided is a method for the computer-assisted operation of an electric motor which is exposed to a thermal load as a result of the rotational motion of its rotor during operation. In this method, measured data is received during the operation of the electric motor. One or more temperature values are derived from the measured data. A number of temperature characteristics curves are then forecast with differing restart times for defining a cooling period for reducing the thermal load on the electric motor, wherein the approximated temperature value, which results from the approximated temperature value is used as the specific starting value for a restart in the temperature characteristics curve to be forecast.

The present invention provides a motor drive device comprising a means for restarting, with a simple configuration, a fan motor that is stuck due to dirt, and a method for controlling said motor drive device. This motor drive device 10 comprises a body 14 having an electronic component 12 inside, a heat radiator 16 attached to the body 14, and external fan motor 18 attached to the heat radiator 16, and an internal fan motor 20 provided inside the body 14. The electronic component 12 includes a processor for controlling the motor for driving a machine tool or a robot, memory, a control circuit, etc., and functions as a restart unit for a fan motor that is stuck due to dirt.

A motor control circuit system is arranged to control the activation of a motor when the input voltage of the motor equals to a predetermined threshold so as to save the power consumption of the motor, wherein no current is allowed to pass to the motor before the input voltage of the motor reaches again the predetermined threshold. Therefore, the motor is electrified in an intermittent manner, such that the driven mechanism runs with its inertia even though the motor is idling, i.e. no current passing to the motor, so as to save the energy consumption of the motor.

A motor control circuit system is arranged to control the activation of a motor when the input voltage of the motor equals to a predetermined threshold so as to save the power consumption of the motor, wherein no current is allowed to pass to the motor before the input voltage of the motor reaches again the predetermined threshold. Therefore, the motor is electrified in an intermittent manner, such that the driven mechanism runs with its inertia even though the motor is idling, i.e. no current passing to the motor, so as to save the energy consumption of the motor.