Abstract: An apparatus for washing skin uses a brushless electric motor and a spring. The apparatus may include a case; an operation unit installed outside the case; a power supply unit installed at one end inside the case; the brushless electric motor installed inside the case; a control unit to output an electric signal; a face-washing brush fitted with a shaft of the brushless electric motor to be rotated forward and reverse as the brushless electric motor is operated; a holder and a spring.

Abstract: A power conversion device includes an inverter which can convert between DC and AC power by turning on and off bridge-connected semiconductor switching elements with free wheel diodes connected in reverse parallel; and a rotating electric machine, such as an AC generator or motor, which is connected to the AC terminals of the inverter, where when the DC voltage of the inverter is below a specified value when starting the machine, the speed of the machine is detected in a condition where the DC voltage of the inverter is boosted to at least a specified value of the induced voltage of the machine, by intermittently turning on and off at least one of the switching elements, so as to accurately detect the speed of the machine and stably start it even when the DC voltage of the inverter is lower than the induced voltage of the machine.

Abstract: A motor control system include an inverter configured to convert boosted direct-current electric power output from a boost converter to alternating-current electric power and supply the alternating-current electric power to an alternating current motor, and a control unit configured to adjust boosted voltage of the boost converter. The control unit includes an optimal boosted voltage map which defines optimal boosted voltage for operating the alternating current motor with a required number of revolutions and required torque, and a boosted voltage changing program that sets boosted voltage of the boost converter to a voltage which is higher than an optimal boosted voltage when the carrier frequency is a predetermined threshold value or lower.

Abstract: A blowing control apparatus for a seat, that includes a blower, and an air hole that is provided in a seating surface and through which air blown from the blower passes, also includes a measuring portion that measures a rotation speed or a current value of the blower as a blower measurement value, and a control portion that determines a degree to which the air hole is obstructed according to the blower measurement value measured by the measuring portion, and controls rotation of the blower by a driving voltage of the blower based on the degree.

Abstract: A rotational speed control system includes a fan controller and a fan controlling circuit. The fan controlling circuit is coupled to the fan controller. The fan controlling circuit can receive a rotational speed control signal and output a fan driving signal to the fan controller. The fan driving signal is a regulated high level voltage signal. The fan controller can adjust rotational speed of the fan according to the driving signal.

Abstract: Systems, methods, and devices relating to control systems for grid-connected inverters. Because grid conditions may vary and because control system stability is dependent on the parameters of the components within the inverter, the present invention adaptably monitors the varying values of these components. Based on the sensed values and on predicted values, controller gains are adaptably adjusted to maintain system stability.

Abstract: To achieve smooth switching of control without fluctuations in speed and torque, an excitation current command is allowed to transit linearly or in accordance with the function of speed between a value under sensorless vector control and a value under low-speed region control in accordance with a speed command or estimated speed in a speed region where the control is switched or in an adjacent speed region where sensorless vector control is performed. Therefore, abrupt variations in excitation current are reduced before and after the switching of the control.

Abstract: A controller of a motor controller operates to perform a process including: controlling the H bridge circuit to switch to the charge mode; controlling the H bridge circuit to switch to the high-dissipation mode when the zero-cross detector detects that the back electromotive force voltage of the motor coil connected to a phase of the H bridge circuit shortly before the H bridge circuit is zero-crossed; controlling the H bridge circuit to switch to the low-dissipation mode after a predetermined time has elapsed; and controlling the H bridge circuit to switch to the free mode when the voltage detector detects that the differential voltage between the motor coils connected to the H bridge circuit is lower than a predetermined voltage.

Abstract: A detection target voltage is divided by a voltage divider circuit wherein a large number of resistor circuits, each of which is formed by a plurality of resistors being connected in parallel, are connected in series, and the voltage is detected. The output of a multiple voltage detector circuit formed of an operational amplifier, and the like, connected to three arbitrary places in the voltage divider circuit is input into a CPU twice, when the switch is in an on-state and when it is in an off-state. The CPU, based on the two measured voltages, can determine that trouble has occurred when there is, for example, trouble such as a short circuit or disconnection of a resistor of the resistor circuits related to the places connected to the three places in the voltage divider circuit.

Abstract: An apparatus for detecting over voltage and/or under voltage can include: a reference voltage receiving unit configured to receive a reference voltage; a gradient measuring unit configured to measure a gradient value of a voltage waveform of the reference voltage; and a pulse conversion unit configured to convert the gradient value into a first pulse width and store it. Further, the apparatus can include: an electrical power receiving unit configured to receive an input voltage from an external power source; and a voltage detection unit configured to compare the first pulse width with a second pulse width to detect an over voltage condition or an under voltage condition.

Abstract: The servomotor control device includes: an inverter circuit that drives a servomotor; a PWM circuit that outputs a PWM signal to the inverter circuit; a cutoff circuit that receives a safety signal and the PWM signal, outputs the PWM signal to the inverter circuit when the safely signal is turned on, and does not output the PWM signal when the safely signal is turned off; and a servomotor control circuit that outputs the safety signal to the cutoff circuit and receives a monitor signal output from the cutoff circuit, the servomotor control circuit turning off, within one cycle time of the PWM signal, the safety signal input to the cutoff circuit where the PWM signal is turned off during servomotor drive and detecting an abnormality when an off state is not detected using the monitor signal.

Abstract: A power converter that reduces a ripple of a torque and a ripple of an electric current in a switch period, having a controller including an instruction calculator that calculates a first voltage instruction value and a second voltage instruction value when, in a first period, a first neutral point voltage is shifted below a center-of-output value, and a second neutral point voltage is shifted above the center-of-output value, and, in a second period, the first neutral point voltage is shifted above the center-of-output value, and the second neutral point voltage is shifted below the center-of-output value.

Abstract: The present invention allows a driving device, which drives a three-phase brushless motor in a sensorless manner, to detect an initial position of the brushless motor and start drive of the motor without performing positioning processing. In a device for driving a brushless motor by sequentially switching six energizing modes, in which two phases to be energized are selected out of three phases, energization is performed sequentially in six energizing modes before start of drive so that the motor does not rotate, and each induced voltage of an opened phase is acquired, induced voltage difference is obtained in each predetermined combination of energizing modes, and it is estimated to which one of six divided regions an initial position of the brushless motor corresponds based on a maximum value of induced voltage differences obtained.

Abstract: A drive device that includes a current sensor that detects a current flowing in the wheel driving rotary electric machine; and shunt resistors that detect currents flowing in the respective second switching element units for the corresponding phases between the direct-current power supply and the second switching element units for the respective phases, wherein a ratio of a period during which current detection can be performed by the current sensor to a control period of the first inverter is higher than a ratio of a period during which current detection can be performed by the shunt resistors to a control period of the second inverter.

Abstract: A method and system for computing a motor speed and a rotor position using a hall sensor are provided. The method improves precision for computing the speed of the motor rotating at a high speed and the rotor position using the hall sensor based on configurations, such as the hall sensor mounted in the motor as a position sensor, a motor controller configured to receive a signal of the hall sensor to operate the motor, and a microcomputer configured to store a time when the motor controller senses the timing of a change in the signal of the hall sensor.

Abstract: In one embodiment, an output overvoltage protection method for a switching power supply, can include: (i) charging a first capacitor by a first current during a first time interval of a switching period of the switching power supply; (ii) charging a second capacitor by a second current during a second time interval of the switching period of the switching power supply; and (iii) generating an overvoltage protection signal by comparing a first voltage across the first capacitor against a second voltage across the second capacitor at the end of the second time interval, where the overvoltage protection signal is active when the first voltage is at least as high as the second voltage.

Abstract: The present disclosure provides a positive and negative rotation control circuit and fan system, which can positively or negatively rotate a fan motor according to an end connecting to different external components or being floating. When the end generates an oscillatory fan signal, the positive and negative rotation control circuit negatively rotates the fan motor for a period of time after the positive and negative rotation control circuit is started for a delay time, to execute the operation of exhausting the accumulated dust, so that a fan connecting to the fan motor may exhaust the accumulated dust from an electronic device. Then the control circuit positively rotates the fan motor to execute the operation of dissipating heat, so that the fan may dissipate heat in the situation of having less dust within the electronic device. Accordingly, the heat dissipation effect of the fan may be enhanced.

Abstract: In-forward-rotation command information is obtained by sampling command signals during one or more rotations of a rotary shaft in a constant speed region while a motor is driven in a forward drive pattern including the constant speed region where the rotary shaft rotates in a forward direction at a constant speed. In-reverse-rotation command information is obtained by sampling the command signals during one or more rotations of the rotary shaft in a constant speed region while the motor is driven in a return drive pattern including the constant speed region where the rotary shaft rotates in a reverse direction at the constant speed. Correction data is generated using the in-forward-rotation command information and the in-reverse-rotation command information.

Abstract: A system for wirelessly programming and diagnosing a motor includes a server computer system, a portable electronic device, and a wireless communication device. The server computer system stores motor operating parameters and other motor data that can be accessed by the portable electronic device over a wireless communication network for identifying a suitable replacement motor for an unserviceable motor. The server computer system also generates motor programming instructions for programming the replacement motor to emulate the unserviceable motor. The portable electronic device wirelessly transmits the motor programming instructions to the wireless communication device for storing the motor programming instructions on a memory of a controller of the replacement motor so that the replacement motor will emulate the unserviceable motor.

Abstract: An electric converter is provided which uses independently controlled field coils to impress a temporary magnetic field on a rotor movable relative to one or more armatures. In some embodiments, the rotor of the programmable electric converter is rotatable with the axis of rotation being on a horizontal or vertical axis. In various embodiments, the electric converter disclosed herein may be adapted for use as a continuous power solution to provide power for a limited period of time in the event of a power outage by absorbing energy and storing it mechanically in the rotor. In some embodiments, the electric converter may be utilized as a generator. In some embodiments, both AC and DC could be simultaneously produced, where AC is generated in one armature coil and DC in another coil. In some embodiments, the programmable electric converter can operate as an AC to AC converter, AC to DC converter, DC to AC converter, or DC to DC converter.

Abstract: A actuator in a HVAC system includes a motor and a drive device driven by the motor. The drive device is coupled to a movable HVAC component for driving the movable HVAC component between multiple positions. The actuator further includes a main actuator controller that determines when the drive device is approaching an end stop and a pulse width modulation (PWM) speed controller that generates a PWM speed output for controlling a speed of the motor. The PWM speed controller sets the PWM speed output to zero in response to a determination that the drive device is approaching the end stop. The PWM speed controller then increases the PWM speed output until the end stop is reached, thereby causing the speed of the motor to increase as the drive device approaches the end stop.

Abstract: An image forming apparatus includes: a light source; a polygon mirror; a brushless motor rotating a rotary polygon mirror; a light receiver configured to receive the light beam reflected by the polygon mirror; and a controller configured to perform driving control; detect a value related to an induced voltage; and perform a phase switching process. In a start-up period, the controller performs a control switching process of performing switching from rotation speed control based on the induced voltage to rotation speed control based on the light receiving timing of the light beam in a specific range in which a length from a start timing of an interruption period of the power to a timing when the detected value reaches the reference value does not become shorter than a length of a reference-disabled period.

Abstract: A motor apparatus includes a full-pitch winding type reluctance motor which has three phase coils formed of full-pitch windings, and a controller which controls applying current to each coil of the three phases. When changing from a state where current is applied to a first phase coil and a second phase coil to a state where current is applied to a third phase coil and the first phase coil, the controller displaces the timing when decreasing the current of the second phase coil is started and the timing when increasing the current of the third phase coil is started from each other.

Abstract: A system and method for controlling switching in an AC-AC converter is disclosed. A controller for the AC-AC converter determines a direction of current flow on supply lines that provide AC power to the AC-AC converter and determines a switching pattern for each of a plurality of line-side switches and each of a plurality of floating-neutral side switches in the AC-AC converter based on the determined direction of current flow on each of the supply lines. The controller causes the line-side switches and the floating-neutral side switches to operate in an ON or OFF condition according to the determined switching pattern, such that a controlled current flow is output from the AC-AC converter. The controller also implements a safe-switching routine when transitioning from a first switching pattern to a second switching pattern that prevents a non-zero current from being interrupted during the transitioning between the first and second switching patterns.

Abstract: Motor drive control apparatus and methods are presented for sensorless control of a driven motor using open loop current regulated control during low-speed operation and an EMF-based position observer for position estimation during higher speed operation, with zero feedback speed during low-speed open-loop operation and feedback speed estimated by the EMF-based observer during high-speed operation and with velocity mode control over the full speed range and mode control hysteresis for smooth transitions between open loop and EMF-based observer control.

Abstract: Embodiments of the present disclosure provide a method that comprises, based upon receipt of a mode command, changing an operating mode of a fan motor controller of a fan to a serial port communication protocol, programming a memory of the fan motor controller with an operating parameter of the fan, and based upon receipt of a serial port command, changing the operating mode of the fan motor controller from the serial port communication protocol to another protocol.

Abstract: A motor control device includes a PWM signal generation unit configured to increase/decrease a duty in both directions of phase lag side and phase lead side regarding a first phase of three-phase PWM signal pattern. The PWM signal generation unit is configured to increase/decrease a duty in one of the directions of phase lag side and phase lead side regarding a second phase. The PWM signal generation unit is configured to increase/decrease a duty in a direction opposite to that of the second phase with reference to any phase of the carrier-wave period regarding a third phase. A timing point adjusting unit is configured to detect two-phase currents at timing points fixed in the carrier-wave period and to adjust a detection timing point so that the current is detectable at a variable timing point regarding at least one phase when the two-phase currents become undetectable at the fixed timing points.

Abstract: A system for determining an initial rotor position of an interior permanent magnet (IPM) machine having a rotor and a stator is provided. The system may include a drive circuit in operative and electrical communication with each phase of the IPM machine, and a controller in electrical communication with the drive circuit. The controller may be configured to engage the drive circuit to selectively apply a voltage signal to each phase of the stator of the IPM machine, detect a current signal through each phase corresponding to the applied voltage signal, and calculate the initial rotor position based on a least squares analysis between at least the voltage signal, the current signal and a predefined inductance of the IPM machine.

Abstract: A driving circuit for a single-phase-brushless motor, includes: a driving-signal-generating circuit to generate a driving signal for supplying, to a driving coil of the single-phase-brushless motor, first- and second-driving currents, alternately with a de-energized period therebetween during which neither of the first or the second driving current is supplied to the driving coil; an output circuit to supply the first or the second driving current to the driving coil in response to the driving signal; and a zero-cross detecting circuit to detect a zero cross of an induced voltage, generated across the driving coil, during the de-energized period, wherein the driving-signal-generating circuit determines a length of a subsequent energized period based on a driving cycle from a start of an energized period, during which the output circuit supplies the first or the second driving current to the driving coil, to a time when the zero-cross-detecting circuit detects the zero cross.

Abstract: The motor driving circuit includes a first converting circuit that outputs an analog voltage proportional to a rotational speed of a motor, a differential voltage calculating circuit that calculates a differential voltage between the analog voltage and a rotation instruction voltage that prescribes the rotational speed of the motor and outputs a differential voltage signal including information on the differential voltage, a duty controlling circuit that outputs, based on the differential voltage signal, a duty controlling signal including information on a control duty that controls a duty of a PWM signal so as to bring the differential voltage between the rotation instruction voltage and the analog voltage close to zero, and a motor driving waveform controlling circuit that generates the PWM signal in response to a signal based on the duty controlling signal and that outputs the PWM signal.

Abstract: An electric power tool is included in a plurality of types of electric power tools. The plurality of types of electric power tools comprise a plurality of types of battery packs having different rated output voltages and a plurality of types of tool bodies, the housings of which are equipped with an attached part on which each of the battery packs is mounted in a freely removable manner. The attached part possessed by the plurality of types of tool bodies equipped with motors having different voltage characteristics is formed so as to be able to mount an arbitrary one of the plurality of types of battery packs having different rated output voltages. This makes it possible to widen the range of available battery packs and enhance convenience.

Abstract: A sensorless brushless motor control device includes a first amplification module common to all motor phases and generating an intermediary voltage signal, a voltage divider between each motor phase and a node on which the intermediary voltage signal is generated, and a computation unit. Each voltage divider generates a first corrected electromotive force with a predetermined average value. The computation unit controls the motor on the basis of the first corrected electromotive forces. By using only hardware components, the control device maintains the average of the corrected electromotive forces at the center of the analog acquisition zone of the computation unit.

Abstract: A method for operating a brushless electric motor, the windings being energized by an inverter with the aid of six switches. A detection unit for detecting defective switches, a unit for measuring voltage at the outputs of the inverter, and a microcontroller for controlling the switch and for generating a pulse width modulated voltage supply for the windings are provided. A short-circuited switch causes a torque in the electric motor opposite the actuating direction of the electric motor. The method proposes that after detecting a short-circuited switch, the windings (U. V. W) are energized to generate a motor torque that is, on the whole, positive. An actuating period of the electric motor is divided into a plurality of sectors, wherein, in accordance with the defective switch, individual sectors are deactivated for the actuation of the windings (U, V, W), while other sectors are used to actuate the windings (V, W).

Abstract: A control device for an alternating current motor according to embodiments includes a current distributor and a phase estimator. The current distributor divides a torque command by using a control phase and outputs a component that contributes to a mechanical output of the motor as a ?-axis current command and a component that does not contribute to the mechanical output as a ?-axis current command. The phase estimator computes a phase at which a ?-axis component of an addition amount of the output of the current controller and a voltage drop amount of inductance of the motor becomes zero and outputs the computed phase as the control phase.

Abstract: A control apparatus of an AC motor improves an electric current estimation accuracy of the AC motor. The control apparatus includes an electric current estimation unit that repeatedly performs an inverted dq conversion, a dq conversion, and a correction process. Based on a d/q axis electric current estimate values of a previous cycle, the inverted dq conversion calculates an electric current estimate value of a sensor phase. The dq conversion calculates a d/q axis electric current correction values based on an electric current estimation error of the sensor phase, which is derived from the electric current estimate value and the electric current detection value detected by an electric current detector. The correction process calculates the d/q axis electric current estimate values of a current cycle by correcting the d/q axis electric current estimate values of the previous cycle by using the d/q axis electric current correction values.

Abstract: There are provided a motor driving apparatus and method, the motor driving apparatus including: a filter controlling unit detecting a frequency of a pulse width modulation (PWM) signal and generating a control signal; a first filtering unit filtering a back electromotive force (BEMF) signal according to the control signal; a second filtering unit filtering a reference signal according to the control signal; and a comparing unit comparing output of the first and second filtering units and generating a motor rotor detection signal.

Abstract: A method and apparatus for controlling a change in a quadrant of operation of a brushless direct current motor. A quadrant change in an operation of a motor is identified. In response to identifying the quadrant change, selected ones of a plurality of switches in a switch bridge are selected to be controlled to couple a direct current power source to the windings of the motor to change a direction of an actual current in the windings.

Abstract: A motor driving device for protecting inrush current is disclosed, where the motor driving device includes a resistor, a capacitor, an electronic switch, a rectifier and a driving circuit. The capacitor is connected to the resistor in series. The electronic switch is connected to the resistor in parallel. The rectifier is connected to the resistor and the capacitor in parallel and is electrically connected to a power source. The driving circuit is connected to the resistor and the capacitor in parallel and is electrically connected to a motor.

Abstract: A brushless motor driving apparatus that rotates and drives a brushless motor, which has a plurality of coils, by switching energization modes corresponding to phases of the brushless motor, sequentially switches the energization modes based on a non-energized phase voltage and a voltage threshold. Also, the brushless motor driving apparatus regulates an upper threshold for energization amount based on the voltage threshold and a change in the non-energized phase voltage at timing of switching the energization mode.

Abstract: There is provided a motor controlling circuit including: a hall signal level detecting unit detecting a hall signal from a hall sensor; and a signal generating unit sensing a change in a level of the hall signal to generate a motor controlling signal according to the change in the level of the hall signal, wherein the signal generating unit determines that the hall signal is maintained at a high level in a case in which a high level maintaining time of the hall signal is equal to or shorter than a preset time.

Abstract: A drive system, for a multi-phase brushless electric motor comprising a plurality of phases, comprises: a drive circuit including switch means arranged to vary the phase voltage applied to each of the phases so as to switch the motor between a plurality of active states; and control means. The control means is arranged to control the switch means so as to provide PWM control of the phase voltages to control the mechanical output of the motor. The control means is arranged to define a sequence for all of the active states and, for each PWM period, to allocate state times for the states required for that period to generate a desired net voltage, and to order the required states in the same order as they occur in the sequence.

Abstract: A motor controlling apparatus including an inverter, a voltage detector, a rotational speed detector, a command value calculating component, an inverter controller, a state detector and an offsetting component. The inverter converts direct-current power to alternating-current power supplied to a motor. The voltage detector detects a direct-current voltage, and the rotational speed detector detects a rotational speed of the motor. The calculating component calculates current and torque command values, and motor rotational speed. The controller provides a control signal to control the inverter based on the current command value. The state detector detects a control state of the inverter, and the offsetting component offsets the detected voltage or rotational speed by an offset amount. The calculating component modifies the current command value based on the offset detected voltage or rotational speed to increase on a negative side a d-axis current command value included in the current command value.

Abstract: Disclosed herein are a system and a method for controlling a speed of a motor. The method for controlling a speed of a motor includes: receiving a signal from a hall sensor of the motor to measure a current speed of the motor; comparing the current speed of the motor measured with a reference speed to calculate errors; outputting a speed control value of the motor based on the calculated errors; limiting the output speed control value to values within a predetermined range; controlling a duty or a phase of current applied to the motor according to the limited values within the predetermined range; and generating a motor driving signal based on the duty control or the phase control and applying the generated motor driving signal to the motor.

Abstract: A method is disclosed for adjusting a voltage of a DC-voltage intermediate circuit in a battery system having a battery and a drive system. The battery is configured to output one selectable output voltage from n+1 different output voltages. In a first step of the method, an actual value of the voltage of the DC-voltage intermediate circuit is determined, and is then compared with the various output voltages of the battery. A first selected output voltage of the battery, which is the highest voltage of those output voltages of the battery which are less than the actual value of the voltage of the DC-voltage intermediate circuit, and a second selected output voltage of the battery, which is the lowest voltage of those output voltages of the battery which are higher than the actual value of the voltage of the DC-voltage intermediate circuit, are then selected.

Abstract: In an electrical machine which has time-varying or position-varying disturbances in its output, signals representing the position and values of machine-related parameters are used to solve a model of the machine to calculate the phase currents which are required to minimize the disturbances. The model is able to provide solutions in the presence of limitations of some of the operating conditions of the machine, for example the supply voltage or the error in the signal representing the position.

Abstract: The present invention includes a voltage applying step of applying an applied voltage including a DC component and a plurality of frequency components to a PM motor, a motor current detecting step of detecting a motor current flowing depending on the applied voltage, and a current control gain adjusting step of calculating a current control gain based on frequency characteristics of the applied voltage and the motor current. In this manner, a stable current control gain having a high current response can be adjusted within a short period of time.

Abstract: A motor constant calculating method for a PM motor according to the present invention includes a voltage applying step of applying an applied voltage including a DC component and a plurality of frequency components to a PM motor, a motor current detecting step of detecting a motor current flowing depending on the applied voltage applied in the voltage applying step, and a motor constant calculating step of calculating a motor constant of the PM motor based on the applied voltage and the motor current.

Abstract: A system for determining if a tire of a vehicle is improperly inflated. The system includes a radar, a wheel speed sensor, and a controller. The radar is configured to emit a signal to detect a reflection of the signal off of an object positioned perpendicular to the vehicle, and to output an indication of a speed of the vehicle. The wheel speed sensor is configured to sense a speed of a wheel of the vehicle. The controller is configured to receive the indication of the speed of the vehicle from the radar, to calculate a speed of the vehicle based on the sensed speed of the wheel, and to determine a tire of the wheel is improperly inflated when the speed of the vehicle calculated using the wheel speed sensor varies by more than a predetermined amount from the speed of the vehicle determined using the radar signal.

Abstract: Systems and methods are provided for diagnosing stator windings in an electric motor. An exemplary method for diagnosing stator windings in an electric motor involves determining an input energy imbalance across phases of the stator windings for an electrical period of the electric motor and identifying a fault condition when the input energy imbalance is greater than a first threshold value. In some embodiments, an input energy ratio across phases of the stator windings is also determined for the electrical period, wherein the fault condition is identified as a phase-to-phase short circuit fault condition when the input energy ratio is greater than a second threshold value and the input energy imbalance is greater than the first threshold value, or alternatively, as an in-phase short circuit fault condition when the input energy ratio is less than the second threshold value.

Abstract: When a current sensor fails, instead of a normal-time motor control section, an abnormal-time motor control section drives and controls a motor. The abnormal-time motor control section detects a timing at which motor current I becomes zero in a state in which all the switching devices are turned off (S11 to S13). Every time the motor current I becomes zero, the abnormal-time motor control section sets an ON time T0 corresponding to steering torque |tr| (S14 to S15), and turns on the switching devices corresponding to the direction of the steering torque for the ON time T0 (S17 to S20). With this operation, an average current Iavg corresponding to the steering torque |tr| flows through the motor 20, whereby deterioration of the followability of steering assist is suppressed.