Abstract: Motor start circuit for an induction motor-with a main winding and an auxiliary winding having two end connections supplied with current via current supply connections, and with a start circuit device serving the purpose of stopping the current flow through the auxiliary winding after the start of the motor, and being connected via a conductor to a control device connected between the current supply connections, and with a preset timer device interacting with the start circuit device to stop the current flow through the auxiliary winding, as soon as a predetermined period after the start of the current flow has lapsed. With the purpose of optimizing the motor start circuit, a voltage presetting device, with which a predetermined voltage value can be set, the start circuit device being disconnected if this value is exceeded, and a period duration presetting device, are connected to or integrated in the control device.

Abstract: The present invention provides a method for controlling motor torque in a hybrid electric vehicle, which can reduce current control mapping time and simplify control algorithm by providing a torque control compensation logic against a change in temperature of a motor (interior permanent magnet synchronous motor) of the hybrid electric vehicle. The present method includes: forming a single current control map based on an engine room temperature; determining a motor operation range that requires temperature compensation according to motor load conditions such as speed and torque; obtaining an optimization formula for torque command compensation; determining a torque command compensation value using the optimization formula; generating a new torque command with the torque command compensation value and applying the new torque command to the single current control map; and applying to a motor a current for which a torque variation according to a temperature change is compensated.

Abstract: There is provided an AC motor controller capable of detecting an abnormal state of a motor cable while an AC motor is operating without using a special circuit but using a processor. The AC motor controller includes an AC motor; an inverter for driving the AC motor with a motor current through a motor cable; and a motor current detector for detecting the motor current flowing in the motor cable of the AC motor, in which a processor detects an abnormal state of the motor cable such as an inter-phase short circuit and an open circuit based on the motor current detected by the motor current detector.

Abstract: A motor drive device of the present invention includes: an output circuit provided with a switch element connected to a motor; a PWM signal generating circuit for generating a PWM signal having a duty corresponding to a ratio between a power supply voltage applied to the motor and a predetermined control voltage; a control circuit for performing on/off control of the switch element according to the PWM signal; and a control voltage generating circuit for generating the control voltage such that the back electromotive voltage of the motor is maintained at a desired value.

Abstract: A motor drive device comprising an H-bridge circuit having four switching elements connected in an H bridge form to a motor coil L, a control circuit for on-off controlling each switching element, and a PWM signal generating circuit for generating a PWM signal having a duty according to a ration between a power supply voltage Vcc and a control voltage Vref, wherein the control circuit is so constituted as to select a switching element to be turned on according to an operation mode control signal FIN, RIN and control its on-duty according to the PWM signal. This constitution can variably control easily and over a wide range a drive voltage applied to one end of the motor coil L according to an externally input control voltage Vref.

Abstract: The invention concerns a reversible current rectifier, for connection to part of a polyphase network and to a continuous bus comprising a plurality of rectifier cells each rectifier cell including a rectifying device and a on-way electronic switch connected in anti-parallel with the rectifier device, the rectifying devices of different cells being arranged so as to form one rectifier. Each rectifier cell comprises means for controlling the electronic switch of the cell arranged to control the latter in closure after detecting a conduction of the rectifying device of the cell so as to enable current to be returned to the network. The control means are arranged to receive a signal external to the cell, for controlling the opening of the electronic switch, derived from another rectifier cell.

Abstract: A motor drive control device and motor startup method prevent startup noise and reduce startup time. At startup, a current to which a rotor does not react is passed through two phase coils of a polyphase DC motor in succession, and a voltage polarity induced in a non-conducting phase is detected. A first operation decodes the detected signal, and determines phase coils of the motor through which a current should pass to rotate the rotor and the energization direction. A second operation forms a control signal for passing a current according to the determination to drive the motor, detects a voltage peak induced in the non-conducting phase during the drive, and performs switching control of a conducting phase. In normal operation, the position of the rotor is detected based on a back EMF in each phase, and rotation control is performed.

Abstract: A drive device for a brushless motor executes an abnormality diagnosis (disconnection/short-circuit) of a motor side circuit. In detecting abnormality of the motor side circuit, the drive device includes a terminal voltage monitor circuit that monitors a terminal voltage of an output terminal that is connected to a motor terminal of respective phases. A microcomputer starts abnormality diagnosis under a condition where the motor is stopped, and an object to be driven has normally operated at the time of driving the motor. For executing the abnormality diagnosis, the microcomputer turns on/off only a transistor of the drive circuit of one phase in a state where all of transistors are turned off, and acquires monitor signals to execute the abnormality diagnosis based on signal levels of the monitor signals.

Abstract: The present invention relates to a secondary air supply arrangement having an actuator operably connected to an air pump for creating air flow between an inlet and outlet of the air pump. A pulse width modulated controller is operably connected to the actuator for applying a pulse width modulated voltage to the actuator. The pulse width modulated controller controls the initial in-rush electric current when the actuator is activated.

Abstract: A method is provided for detecting a stall condition in a stepping motor. The stepping motor has two coils and a rotor, and is micro-stepped by substantially continuously driving both of the two coils with out-of-phase time varying voltages. The method includes stepping the stepping motor to a next micro-step. It is then determined when a predetermined motor parameter of a first coil of the two coils is to be sampled. To sample the predetermined motor parameter of, for example, the first coil, the first coil is opened for a predetermined period, wherein the predetermined period is less than or equal to a micro-step. Then the first coil is sampled during the predetermined period and the result of sampling is integrated and used to increment or decrement an accumulated value. If the accumulated value is less than a preset value, then a stall condition exists.

Abstract: A high current end power stage comprises at least four power transistors, two electrical supply lines and a safety fuse. The at least four power transistors have each a diode which is blocked during normal operation of the respective power transistor. The two electrical supply lines couple the at least four power transistors with a supply potential and a reference potential such that two of the at least four power transistors are connected electrically between the supply potential and the reference potential. The safety fuse is connected in series to the at least four power transistors in at least one of the two electrical supply lines. The at least one safety fuse can be triggered by a current which flows through the diode of the at least four power transistors, said diode being then arranged in the direction of conduction, when the supply potential and reference potential are exchanged.

Abstract: Disclosed is a method for screwing in and tightening a screw connection (1) to a predetermined tightened level (2), especially a predetermined torque level (2) or a predetermined pretension level, with the aid of a hand-held screwing tool (3) comprising a regulated drive unit (4) and/or control functionality, particularly an electric nut runner (3). A tightening phase (B-C-D), during which the screw head rests against the supporting surface (6) of the screw connection (1), starts following a screwing phase (A). In order to improve said method, the speed (N) of the screwing tool (3) is increased to an output speed (7) for the tightening phase (B-C-D) within an acceleration time (8) in the tightening phase (B-C-D) and is lowered within a delay time (9) prior to or until reaching the predetermined tightened level (2).

Abstract: In order to enable in a motor system, in which a soft start of the motor has been implemented, the operation of the motor, wherein the power consumption is reduced, it is proposed to operate the driver circuit during a switch-on phase in order to carry out a soft start of the motor. In at least one embodiment, the driver circuit can be bypassed in a normal operational phase as a function of a load, by means of which the motor is operated.

Abstract: A motor unit and a vehicle equipped with the unit according to the invention includes a control unit that selects a switching frequency, that is, a carrier frequency, in accordance with a rotation speed of the motor and a torque required from a motor. When an inverter temperature becomes high, the control unit limits the torque of the motor to suppress further increase in the inverter temperature. A limit value used in restricted operation is determined in accordance with the temperature and the carrier frequency of the inverter.

Abstract: An electric tool switch mechanism includes a trigger switch for operating to at least rotate or stop a DC motor; and a power switch connected between the DC motor and a battery power source and closed when a pressed amount of the trigger switch exceeds a predetermined threshold value. The mechanism further includes a switching device connected between the DC motor and the battery power source via the power switch; a control circuit for controlling to turn the switching device on/off using a desired on-duty when the pressed amount of the trigger switch exceeds the threshold value; and a stopping unit that is controlled by the trigger switch for forcibly turning the switching device off before the power switch is changed from on to off when the trigger switch is released.

Abstract: In response to a system-off instruction, the drive system control technique of the invention controls individual motors of an electric cooling water pump and an electric cooling fan to stop (step S100), waits for elapse of a preset reference time period since start of the control of stopping the motors (step S110), and turns off a relay to disconnect a supply of electric power from a battery to a CPU of a control unit (step S120). Inactivation of the relay after elapse of the preset reference time period since start of the control of stopping the motor disconnects the supply of electric power to the control unit in the state of sufficiently low back emf generated by the motors. This arrangement effectively prevents malfunction of the control unit due to the back emf generated by the motors.

Abstract: A method, apparatus or computer program implements an overload prevention approach involving monitoring a speed of a motor; detecting an overload condition of the motor based on the monitored speed; and controlling an operation of the motor according to the detected overload condition.

Abstract: Methods and systems are provided for controlling permanent magnet machines under varying loads. The method comprises generating a d-axis voltage command and a q-axis voltage command, producing a modified d-axis current command based on the q-axis voltage command and a d-axis current command, converting the modified d-axis current command to a modified d-axis voltage command, and transmitting the modified d-axis voltage command and the q-axis voltage command to the PM machine. The d-axis voltage command is based on a d-axis current command.

Abstract: An electric vehicle is provided with an electric motor and a transmission capable of being shifted by a shift mechanism from a neutral state to a start-up speed stage selected state in which a speed stage for start-up of the vehicle has been selected. On a request for a shift from the neutral state to the start-up speed stage selected state, an ECU performs the requested shift by controlling the shift mechanism. If the shift to the start-up speed stage selected state is not completed within a first specified time, the ECU performs a rotating position control in which the motor is controlled to produce a predetermined minute torque in forward and backward rotation directions of the motor, alternately, and a gear of the speed stage for start-up is caused to oscillate in a rotation direction by the minute torque being transmitted to an input shaft of the transmission.

Abstract: A method and apparatus for a pump control system. One or more embodiments of the invention include a pump controller that can perform a self-calibrating procedure, can provide precise motor speed control, can provide a limp mode before shutting down the motor when system parameters are exceeded and/or fault conditions occur, can detect fault conditions, and can store fault conditions for later retrieval.

Abstract: Embodiments of the invention provide a disk device and a method of controlling the device which is capable of suppressing peak current, even for serial communication, that is required when initiating rotation of a spindle motor down to a level equivalent to that of parallel communication, without prolonging elapsed time before reaching the steady rotation speed. In one embodiment, an HDD includes a serial communication circuit which executes serial communication with a host, an SPM which rotates a disk, an HDC/MPU which controls the SPM and the serial communication circuit. The HDC/MPU, after shutting down the serial communication circuit once, starts up the serial communication circuit again when rotation speed of the SPM reached the specified standard value, and establishes serial communication with the host by means of the serial communication circuit.

Abstract: A driving mode switching apparatus for a four-wheel-drive vehicle, which switches driving modes of the four-wheel drive vehicle, includes a motor, a reduction mechanism being transmitted with a rotational force of the motor, an output rod connected to the reduction mechanism and switching the driving modes by being displaced, a housing housing the motor and the reduction mechanism, a temperature sensor arranged at a position away from the motor within the housing and detecting ambient temperature in the housing, and a controller varying an output property of the motor in response to a detected temperature by the temperature sensor.

Abstract: The invention relates to a soft starting method and system thereof in the way of wave-skipping with stepped frequency and stepless voltage regulating for a motor which can be applied to the large torque starting of AC motor under the condition of a power supply of a industrial frequency supply source and the safe starting of higher load. Trigger signals generated by a control system, in the soft starting method of the invention, act on five sets of anti-parallel thyristor valves connected between the power supply and the motor to conduct a pair of thyristors thereof according to a set frequency and sequence, and the motor is started from a standstill status to full speed in the way of wave-skipping by controlling the sets of the thyristor valves. The method may improve the starting torque for more than 10 times of the traditional motor soft starting of the voltage reduction and control the starting current for about two times of the rated current.

Abstract: A starting device for an internal combustion engine, especially that of a motor vehicle, comprises: a stator, or inductor, comprising an inductor coil (5), said inductor coil comprising at least first (43), second (41) and third (42) windings that are all electrically connected in parallel; a rotor associated with said stator and having a longitudinal axis; a starter element that can be rotated by the rotor; and a contractor designed to supply power, in a prerotation first phase, only to the first winding (43) of the inductor coil and, in a full-speed second phase, following the first phase, to the first, second and third windings (41, 42) of the inductor coil.

Abstract: A control system includes a controller configured to provide a drive signal, and a switching device configured to generate an output control signal as a function of the drive signal in an on-state mode of operation. The control system also includes a timing network configured to receive the drive signal and output a gated signal to the switching device, wherein the gated signal maintains a relationship with a predetermined threshold during the on-state of operation of the switching device.

Abstract: The inverter device contains the following structure: an inverter circuit which has upper-arm switching elements that are connected on a positive side of a DC power source and lower-arm switching elements that are connected on a negative side of the DC power source; a current sensor that detects current flowing between the DC power source and the inverter circuit; and a control circuit that controls the inverter circuit by a PWM driving so that the inverter circuit outputs AC current to the motor. The control circuit provides a carrier cycle with a first correction and provides the successive cycle with a second correction, by which the current sensor can detect phase current of the motor. A ripple current caused by the first correction and a ripple current caused by the second correction are opposite in polarity.

Abstract: A hybrid fuel cell vehicle with a multi-power source and a multi-drive system includes: a plurality of primary power sources sharing a single main bus terminal and connected in parallel to each other; a plurality of drive systems receiving power from the main bus terminal to generate output torque so as to drive vehicle wheels and connected in parallel to each other; and an auxiliary power source sharing the main bus terminal and disposed between the primary power sources and the drive systems to supplement power shortage of the primary power sources.

Abstract: A power tool has an electric motor with field windings. In an aspect of the invention, each field winding includes two coils wound with the same number of turns of the same gauge magnet wire. When the motor is first energized, the two coils of each field winding are connected in series, reducing in-rush current. Upon expiration of a soft start period, which can be after the motor reaches a predetermined speed or upon expiration of a predetermined time period, the two coils of each field winding are connected in parallel. In another aspect of the invention, an electric motor used in a power tool includes field windings that are connected in series with a separate start winding when the motor is first energized. Upon expiration of the soft start period, the start winding is bypassed. In another aspect of the invention, the separate start winding includes two sub-windings.

Abstract: A materials handling vehicle is provided comprising: a frame; wheels supported on the frame; a traction motor coupled to one of the wheels to effect rotation of the one wheel; a speed control element operable by an operator to define a speed control signal corresponding to a desired speed of the traction motor; a system associated with a steerable wheel to effect angular movement of the steerable wheel; and control apparatus coupled to the speed control element to receive the speed control signal, and coupled to the traction motor to generate a drive signal to the traction motor in response to the speed control signal to control the operation of the traction motor. The control apparatus may determine an acceleration value for the traction motor based on at least one of an angular position of the steerable wheel, a speed of the traction motor and a current position of the speed control element as defined by the speed control signal.

Abstract: A controller for an electric motor in a blower system includes an input for receiving an air flow demand. The controller is configured for producing drive signals for the electric motor from the air flow demand using an equation having a plurality of terms. At least one of the terms includes a composite function S*CFMn, where S is a speed of the electric motor, CFM is the air flow demand, and n>1. These teachings can also be applied to other types of fluid handling systems including, for example, liquid pumps.

Abstract: A method and apparatus for controlling a rotation of a motor in a disk drive. The method includes: performing spin-up when the disk drive is operating and determining whether a disk rotation speed is less than predetermined target constant revolutions per minute (RPM); rotating a disk at predetermined low RPM when determining that the disk drive is at a low temperature and changing a rotation mode to a low-speed rotation mode if it is determined that the disk rotation speed is less than the predetermined target constant RPM; and spinning up the disk to the target constant RPM when determining that the temperature of the disk drive has increased and changing the rotation mode to a high-speed rotation mode if a disk rotation driving current decreases below a predetermined reference current value while the disk is rotating at the low RPM.

Abstract: An apparatus for controlling a motor includes a plurality of switching elements configured to switch energizing phases of the motor; and a driving unit configured to drive at least one of the switching elements. The driving unit drives a predetermined switching element from among the switching elements so as to position the rotor to a predetermined position. When starting the motor, the driving unit first drives the predetermined switching element.

Abstract: A starting circuit for a single-phase AC motor, comprising a main winding, a detecting circuit, a rectifying and filtering circuit, a triggering circuit, a switching circuit and a starting winding. The detecting circuit is connected in series to the main winding for transforming current parameters thereof into detecting signals. The switching circuit is connected in series to the starting winding. The rectifying and filtering circuit processes the detecting signals and the processed detecting signals to the triggering circuit. The triggering circuit enables or disables the switching circuit according to the detecting signals, so as to energize or deenergize the starting winding. The starting circuit features high reliability, long lifetime, simple circuit structure, low cost, and small size.

Abstract: A motor circuit protector that trips in accordance with an instantaneous trip curve that is split into three protection regions, a self-protection region, an in-rush avoidance region, and a locked-rotor avoidance region. Software modules for detecting whether primary current exceeds each region are run in parallel or simultaneously, providing redundant instantaneous trip detection, and these redundant protection regions remain active throughout the startup and steady-state modes of operation of the motor circuit protector. This redundancy provides improved time current trip performance for a wide variety of short circuit conditions and improved system safety properties are realized. The current threshold for the self-protection region can be adjusted toward the in-rush avoidance region once steady-state operation is achieved. In startup mode, only the self-protection region may be detected, but can remain active during steady-state mode.

Abstract: A hand-held power tool has an electric drive motor having a drive shaft and a tool connected to the drive shaft and rotatably driven by the drive shaft. The drive motor has a control device that has correlated therewith at least a first operating curve and a second operating curve. The control device operates the electric drive motor in idle according to the first operating curve and operates the electric drive motor under load according to the second operating curve. The first operating curve covers the low power range at low speed and the second operating curve covers a large power range at high speed.

Abstract: A first illustrative embodiment includes an actuator having both a Run state and a Hold state, the actuator including circuitry for detecting power supply abnormalities and causing the Run state to occur following a power supply abnormality. In another illustrative embodiment, the present invention includes an actuator having both a Run state and a Hold state, the actuator including a power detect circuit that keeps the actuator from entering the Hold state when the power supply is below a certain level.

Abstract: A control device for soft starting and protecting overload of a motor in a power tool is disclosed. The control device comprises a power switch, a varistor, several diodes, several resistors, several capacitors, a relay, a transistor, a triac, and a microcontroller. The microcontroller is embedded with program such that, after the power switch is turned on, the microcontroller generates a smooth soft start voltage to drive the power tool. With the characteristics of power-control device, the voltage sent to motor is increased from low to full range. When the speed of motor is increased from low to the maximum, the microcontroller turns off the power-control device and turns on a relay.

Abstract: Different circuit-based implementations of stochastic anti-windup PI controllers are provided for a motor drive controller system. The designs can be implemented in a Field Programmable Gate Arrays (FPGA) device. The anti-windup PI controllers are implemented stochastically so as to enhance the computational capability of FPGA.

Abstract: A DC motor phase detection algorithm that monitors the change in motor current to detect pulses in the current caused by the motor's commutator brushes crossing over the gap between rotor commutator segments as the motor shaft rotates. A pulse is generated each time a commutator brush breaks and then reconnects to a commutator segment. The algorithm detects and counts the pulses in order to determine the number of revolutions the shaft has rotated. The motor phase can then be used to determine the distance, rotational or linear, that the moving portion of the load attached to the motor has traveled. If the initial position of the moving portion of the device is known then the absolute position can be calculated.

Abstract: Methods and apparatus are provided for preventing a voltage overload condition of an alternating current (“AC”) motor electrically coupled to an inverter. In an embodiment, the system includes an oil pump, a motor in communication with the oil pump, an inverter module in electrical communication with the motor, the inverter module configured to generate a speed command, and a controller module. The controller module is in communication with the inverter module and the motor and is configured to determine an error, based, in part, on an estimated torque value of the motor and a predetermined maximum available torque value, to convert the error into a first value, to limit the first value between a negative value and zero, and to add the first value to the speed command from the inverter to thereby generate a final speed command for the motor.

Abstract: A motor driving circuit generates pulse driving signals, and controls the ON/OFF state of a switching circuit connected to a coil of a motor which is to be driven, thereby controlling the conduction period of the motor. A driving signal generating circuit generates the driving signals such that they are pulse modulated according to the torque target value for the motor, and outputs the driving signals to the switching circuit. A current detection circuit detects the current flowing through the coil of the motor. A current limiting circuit controls the logical values of the driving signals generated by the driving signal generating circuit such that the current detected by the current detection circuit does not exceed a predetermined current upper limit. The current limiting circuit increases the current upper limit according to the time elapsed in the starting operation of the motor. After the starting operation of the motor, the current upper limit is set to a predetermined fixed value.

Abstract: An inverter that supplies a desired primary voltage (v1) to an induction motor, a current detector that detects a primary current (i1) from the inverter to the induction motor, a voltage designation value calculating unit that generates a voltage designation value (v1*) for generating the voltage v1, an idling-time speed estimating unit that calculates an estimate value (?r#) of the rotation speed when the induction motor is idling, and a sequence circuit that commands the operations of these units are provided. The idling-time speed estimating unit switches a method for deriving the estimate value on the basis of a current value in the case where a short circuit is generated between windings when the induction motor is idling.

Abstract: A hybrid electric vehicle is arranged such that a driving force of an engine and a driving force of an electric motor can be transmitted to driving wheels through a transmission and that the engine and the transmission can be mechanically connected and disconnected by means of a clutch. When an upper limit decelerating torque generable by the electric motor is equal to or greater than a requested decelerating torque, a vehicle ECU disengages the clutch and controls the electric motor to generate the requested decelerating torque. Meanwhile, when the upper limit decelerating torque is smaller than the requested decelerating torque, the vehicle ECU engages the clutch and controls the engine and the electric motor so that the sum of a decelerating torque generated by the engine and a decelerating torque generated by the electric motor is equal to the requested decelerating torque.

Abstract: A power converting device for an electric train includes a power converter, an alternating-current motor, a primary control unit, and a control unit. The power converter converts direct-current power into alternating-current power. The alternating-current motor is driven by the alternating-current power output from the power converter. The primary control unit outputs a power-running notch command that determines an acceleration speed for the electric train. The control unit controls an amount of the alternating-current power based on the power-running notch command. The control unit sets the amount of the alternating-current power to zero without a delay after receiving an OFF signal of the power-running notch command during power running.

Abstract: A method and a device with a control apparatus (50) for starting an electric machine (10) with a rotor (20), particularly the spinning cup of an open-end spinning machine, magnetically mounted by a bearing having permanent magnets (31, 32, 33, 34). An actuator system controls the position in the axial direction (35, 36) and two limitation bearings (41, 42), determine the axial end positions of the rotor. The actuator system brings about a lifting from the first axial end position, and a system variable during such lifting is compared with a reference value, and the rotor (20) is moved into the second end position, and the actuator system brings about a lifting from the second axial end position, and a system variable on lifting from the second end position is compared with a reference value.

Abstract: Method of and system for controlling the restart of an A.C. motor drive comprising an A.C. motor (4), a power converter (20, 21, 22) for stepless speed control of the A.C. motor and a load switch (3) arranged between the power converter and the A.C motor, wherein when the power converter (20, 21, 22) detects the output current to go below a predefined limit during the load switch opening it goes to a continuous output sensing mode, and when the output current goes above a predefined limit during the output sensing mode the power converter restarts automatically to a desired operating state.

Abstract: The present invention relates to a method of driving a three-phase electric motor, comprising measuring a three-phase excitation current by selectively exciting two phases; calculating a current difference between excitation phase currents having the same phase; classifying the current difference according to variation; and calculating a rotator position in the three-phase motor on the basis of a classification result and the magnitude of the excitation phase current. Thus the present invention provides an electric motor driving apparatus and a driving method which can be applied to various kinds of motors and which precisely measures an initial position of the rotator.

Abstract: Motors comprising stators and rotors having a plurality of north poles and south poles and methods of controlling the same. A first sensor and a second sensor are provided. The first and second sensors are disposed on the stator in a manner that the first and second sensors never simultaneously detect boundaries between the north and south poles during rotation of the rotor. If any one of the first and second sensors continuously detects a north pole or a south pole for a predetermined duration, the motor is shut off.

Abstract: A disk drive system is set forth that comprises a rotatable storage medium adapted to store data, a spindle motor disposed to rotate the rotatable storage medium, and a spindle motor control system. The spindle motor control system brakes rotation of the spindle motor in response to inductive sensing of the rotation of the spindle motor.

Abstract: The present invention is a motor control device comprising a control system, the control system being capable of controlling the motor by PWM and having integration means being capable of outputting an integrated value obtained by integrating a deviation between a rotation speed and a target rotation speed of a motor, the motor control device being capable of starting control with the control system for causing the motor to rotate at the target rotation speed after rotation of the motor has been started. In this motor control device, an output value of the integration means at a time when control with the control system is to be started is set to have a value that corresponds to a counter electromotive force generated in the motor by its rotation.