Abstract: Provided is a pump system. The pump system includes an AC (alternating current) electric motor, a converter, a smoothing unit, an inverter, a volt/hertz pulse width-modulation controller, and a main controller. The AC electric motor operates a pump which is a load. The converter receives AC power and converts the AC power into DC (direct current) power. The smoothing unit smoothes a DC voltage converted by the converter. The inverter converts the DC voltage output from the smoothing unit into an AC voltage. The volt/hertz pulse width-modulation controller applies switching voltage to a semiconductor switching device of the inverter. The main controller changes an operating frequency according to a load detected when the Ac electric motor is in operation and puts the AC electric motor to a sleep mode after determining a load operation status.

Abstract: A system comprising an actuator and a controller configured to drive the actuator with a pulse width modulated (PWM) signal. The controller is configured to limit a duty cycle of the PWM signal in response to a current supplied by the PWM signal.

Abstract: An electric motor includes a magnet rotor which is placed with an air gap interposed between it and a stator and has a magnetic pole portion formed from a plastic magnet which swells by hydrogen bonds, an inverter circuit, a DC-voltage conversion portion, a driving logic control portion, a supply current value control portion, a current value designation portion, a reference current value designation portion, and a correlation designation portion, wherein the correlation designation portion determines an average current value by changing the average current value linearly or non-linearly with respect to a reference current value, and the magnetic pole portion absorbs moisture to swell, thereby making the air gap smaller, at higher humidity than a reference humidity.

Abstract: A control method comprises determining wheel creep of a wheel operably coupled to a traction motor and limiting a rate of change of an excitation frequency applied to the traction motor to drive the wheel, based on the determined wheel creep. According to one aspect, the rate of change of the excitation frequency is limited if the wheel creep exceeds a wheel creep threshold.

Abstract: A motor driving device comprises: an AC/DC converter that converts alternating current power into direct current power; a motor driving unit that operates based on the direct current power supplied from the AC/DC converter and outputs a driving signal to a motor; and a start-up auxiliary circuit that is arranged on a path connecting the AC/DC converter and the motor driving unit, wherein the start-up auxiliary circuit: delays an output of the driving signal for a first predetermined time period after the supply of the alternating current power from the alternating current power supply to the AC/DC converter starts; and gradually increases a driving voltage so that current flowing in a driving coil of the motor is limited to a predetermined value or smaller for a second predetermined time period after the output of the driving signal from the motor driving unit starts.

Abstract: An electric motor drive apparatus includes multiple inverter sections arranged corresponding to winding sets of a motor, multiple relays that controls power supplies to the inverter sections, and a control unit. Each inverter section and corresponding winding set are referred to as a system. The control unit includes an obtaining section that obtains a winding current, a determination section that determines a fault occurrence, a specifying section that specifies a faulty system in which the fault occurs, an interrupting section that controls the relay corresponding to the faulty system to interrupt the power supply to the faulty system, and a vibrating section that controls the inverter section of a properly-operating system to add a vibration to an output torque from the electric motor. The vibrating section gradually increases a vibration component of the vibration added to the output torque from the electric motor.

Abstract: The electric tool is powered by a secondary battery as a power source, and includes: an output section configured to be transmitted thereto a rotation of a motor directly or through a decelerator; a voltage measurement section that measures a battery voltage; a storage means that stores, as a reference voltage, a voltage value of the battery voltage measured preliminarily when a motor-lock is occurring; and a control means that controls a driving of the motor. The control means is configured to decide that the motor is being locked and then stop or decelerate the motor upon detecting that the battery voltage measured through the voltage measurement section is maintained lower than or equal to the reference voltage stored in the storage means for a predetermined period of time during the driving of the motor.

Abstract: The present invention relates to a self-propelled working machine, especially in the form of a surface milling machine, such as asphalt-milling machine or snow-milling machine comprising a main operating unit and/or a drive unit, which is operable in a steady-state or near steady-state operating status and is drivable by a drive device comprising at least an electrical motor, the electrical motor being associated with a start-up including a frequency converter for the limitation of starting current. The invention also relates to a process for operating such a self-propelled working machine. According to the invention an operating circuit for steady-state operation is provided, comprising a jumper for bridging the frequency converter following starting or reaching steady-state operational status. Optionally, the jumper is switchable to activate or inactivate the frequency converter of the start-up circuit, respectively.

Abstract: A motor control device has a drive circuit that drives an electric motor with a battery as a power supply, a switch element that is provided between the battery and the drive circuit, the switch element supplying a current from the battery to the drive circuit when being turned on, the switch element cutting off the current from the battery to the drive circuit when being turned off, a rotation speed detector that detects a rotation speed of the electric motor, and a controller that operates the drive circuit to control the electric motor. The controller turns on the switch element when the rotation speed of the electric motor, which is detected by the rotation speed detector, is greater than or equal to a first predetermined value during stopping of the control of the electric motor.

Abstract: A soft start circuit for a forward/reverse rotation fan includes a forward/reverse switch unit, a soft start activation unit, a soft start control unit, a Hall IC and a driver IC, wherein the soft start activation unit comprises a first signal transmission loop and a second signal transmission loop. The soft start circuit activates the soft start control unit via a first instantaneous signal outputted by the first signal transmission loop or a second instantaneous signal outputted by the second signal transmission loop to make the soft start control unit output a control signal to a speed control terminal. When the rotating direction of fan is switched from one direction into another, the fan starts rotation in a soft start mode owing to high level of the control signal transmitted from the soft start control unit to the speed control terminal during initial rotation of the fan.

Abstract: Disclosed is a method for setting a current sensor of a vehicle having a drive motor according to an exemplary embodiment of the present invention may include confirming a first condition that a vehicle stops its movement, confirming a second condition that a required torque of a drive motor of a vehicle is 0, stopping a current that is supplied to the drive motor if the first condition and the second condition are satisfied, and compensating offset of the current sensor of a drive motor control unit controlling the drive motor. The offset may be compensated if the first condition and the second condition are satisfied for a predetermined time. Accordingly, an offset of the current sensor is compensated in a predetermined driving condition that the vehicle stops moving and therefore the creep surge and the motor torque ripple that can be generated in the vehicle are prevented.

Abstract: [Problem] An object of the present invention is to provide a power state diagnosis method and a power state diagnosis apparatus that pass and increase not only a d-axis current but also a q-axis current to a current value that a steering behavior does not occur to perform a diagnosis in the vector control of a motor, and determine that a power supply degraded, that the power supply is normal and that the diagnosis is not completed without giving an uncomfortable feeling to a driver, detecting a timing that there is not a driver, and needing to comprise a plurality of actuators.

Abstract: A control system for an electric vehicle has a vehicle speed calculation section that calculates a speed of the electric vehicle and a control unit that controls an inverter of an electric motor to provide road wheels with a predetermined reference torque in accordance with a manipulated value of an accelerator pedal, wherein the unit has a reference torque correction section that changes the reference torque from an original value and then returns the changed reference torque to the original value when a calculated speed of the electric vehicle is in a given speed range.

Abstract: An electric motor driving apparatus having a failure detection circuit includes: a bridge circuit driving an electric motor; a PWM control circuit generating voltage instruction for driving the electric motor; a PWM signal generation circuit generating a PWM signal; a DC current detection circuit detecting DC current of the bridge circuit; a phase current calculation circuit calculating output phase current of the bridge circuit, based on the DC current and PWM signal; and a failure detection circuit detecting failure of the DC current detection circuit. The failure detection circuit determines failure of the DC current detection circuit from the DC current detected values in a zero voltage period in which the high-potential-side arms of the bridge circuit are all ON and in a zero voltage period in which the low-potential-side arms are all ON.

Abstract: A motor control device has a drive circuit that drives an electric motor with a battery as a power supply, a switch element that is provided between the battery and the drive circuit, the switch element supplying a current from the battery to the drive circuit when being put into an on state, the switch element cutting off the current from the battery to the drive circuit when being put into an off state, a voltage detector that detects a voltage at the drive circuit, and a controller that operates the drive circuit to control the electric motor. The controller turns on the switch element when the voltage at the drive circuit, which is detected by the voltage detector, is greater than or equal to a first predetermined value during stopping of the control of the electric motor.

Abstract: An electric tool comprises a removable battery pack 2 as a power supply, a motor M as a power source, a drive unit being driven by said motor, a switch SW as an operation input unit, and a control circuit CPU controlling the driving of said motor according to the operation of said switch. The electric tool further comprises a power supply connection unit that enables a plurality of battery pack types, which have different rated output voltages, to be selectively connected, and an identification means that identifies the type of said battery pack that has been connected. Said control circuit is configured to control an output of said motor based on identification information for the type of said battery pack that has been connected, provided by said identification means.

Abstract: A control apparatus for an AC rotary machine includes a control circuit, a power converter, a current detector, and a voltage detector. The control circuit includes: an activation current instruction unit which generates a current instruction for activation; and a start phase setting unit which sets an initial rotation phase for activation control, based on the rotation direction of the AC rotary machine just after activation and on the polarity of current detected by the current detector just after activation. Thus, the current amplitude and torque shock just after activation control is started can be reduced, and assured and stable reactivation is allowed without causing the protection operation.

Abstract: Methods and systems for starting an electric motor using a motor controller including a processor are provided. The method includes determining if the electric motor is operating, increasing a failed start counter if the electric motor is determined not to be operating, determining a reverse rotation by comparing a failed start counter to a predetermined threshold, and applying a reverse rotation start routine to the electric motor when a reverse rotation is determined.

Abstract: A thermal stress reduction method includes ramping an electric power generator to start an aircraft engine, for a time period associated with the aircraft engine start sequence toggling a three-level inverter switch array to a three-level pulse width modulation mode, determining if a first time interval in the three-level pulse width modulation mode exceeded a predetermined three-level pulse width modulation mode interval, in response to the first time interval exceeding the three-level pulse width modulation mode interval, toggling the three-level inverter switch array to a two-level pulse width modulation mode, determining if a second time interval in the two-level pulse width modulation mode exceeded a predetermined two-level pulse width modulation mode interval and in response to the second time interval exceeding the two-level pulse width modulation mode interval, toggling the three-level inverter switch array to the three-level pulse width modulation mode.

Abstract: A driving apparatus for an electromagnetic load, said apparatus having at least one pair of first and second transistors arranged so as to form a current path with the electromagnetic load for discharging the current produced by the electromagnetic load. The first transistor has an inherent diode between the non-drivable terminals and the apparatus is configured to control switching of the pair of first and second transistors, to diode-connect the second transistor, with said first and second transistors switched off, so that the current produced by said electromagnetic load, crossing said inherent diode, creates an overvoltage between the terminals of the second diode-configured transistor such to exceed the conduction threshold voltage thereof.

Abstract: The invention relates to a method for providing a trigger signal in response to the commutation of a mechanically commutated electric motor (1). The method comprising the steps of providing a mechanically commutated electric motor (1), providing a power supply for said mechanically commutated electric motor via electrical supply leads (10, 11) from power supply circuitry, providing a filter (15) connected to said electrical supply leads (10, 11), detecting with said filter (15) a voltage spike occurring at commutation, outputting from said filter (15) said trigger signal.

Abstract: A device and method to determine the stopping rotor position of a washing machine motor includes an inverter, a permanent magnet synchronous motor, and an electronic motor controller. The controller determines the stopped rotor position of the motor by measuring induced currents in the stator field coils of the motor. While the motor is de-energized and slowly rotating, the controller directs the inverter to connect all of the stator field coils of the motor together. The stator field coils may be connected to a common D.C. rail, output from an A.C.-D.C. converter of the washing machine. In an embodiment, the controller determines the rotor position based on the polarities of current induced in the stator field coils. In another embodiment, the controller determines the rotor position based on the phase angle and angular frequency of the three phase currents, transformed into a stationary reference frame.

Abstract: Motor Drive Control Device configured to properly start up various types of motors under operating conditions where motor operations are performed in a wide range of temperature and power supply voltage, includes output drive controllers that supply PWM drive output signals to an output pre-driver in such a manner as to minimize the error between a current instruction signal and a current detection digital signal. In response to a detected induced voltage generated from a voltage detector upon startup of a motor, an initial acceleration controller supplies initial acceleration output signals specifying a conducting phase for initial acceleration of the motor to the output drive controllers. The initial acceleration controller, the output drive controllers, and an output driver make a conducting phase change and perform a PWM drive to provide the initial acceleration of the motor.

Abstract: Integrated AC regenerative motor drives and operating methods are presented in which a precharging circuit is provided with an IGBT, a diode and a parallel current limiting component in an intermediate DC circuit between a switching rectifier and an output inverter, and the drive is operated in one of three modes for motoring, regenerating and precharging.

Abstract: The present invention relates to a method for starting a washing machine electric motor and, more particularly, an adaptive method for starting a washing machine electric motor, which is especially able to control the firing angle (preferably during the centrifugation cycles) of the voltage cycles depending on the electrical supply voltage and its possible and unpredictable variations and/or oscillations. Such firing angle control of the electrical supply voltage of the electric motor comprises a dynamic control based on the result of the comparisons in the previous steps, and is performed by generating at least one additional correction signal (ASC) based on the result of the comparison between the actual value of the electrical supply voltage of the electric motor and at least one predetermined reference value, and the additional correction signal (ASC) being responsible for controlling the firing angle of the electrical supply voltage of the electric motor.

Abstract: [Problem] An object of the present invention is to provide a motor controlling apparatus that comprises a single current sensor and obtains a maximal duty range that current becomes detectable with realizing size reduction, weight saving and cost reduction and an electric power steering apparatus using the same.

Abstract: Embodiments of the present invention permit the optimization of torque control of a permanent magnet machine including obtaining instantaneous terminal voltages of the machine, transforming the instantaneous terminal voltages to a zero direct axis voltage and a non-zero quadrature axis voltage, using a mathematical transformation, regulating the electrical frequency of the permanent-magnet machine such that the zero direct-axis voltage is adjusted to have a value of zero, determining a non-final electrical angle of the permanent-magnet machine by applying an integrator to the regulated electrical frequency of the machine, determining a final electrical angle of the of the machine by integrating the non-final electrical angle and an electrical angle from a previous calculation cycle, and regulating the current vector of the machine such that the current vector is perpendicular to the final electrical angle of the machine, thereby optimizing the torque of the machine.

Abstract: An electric power tool includes a motor that rotary drives an output shaft; an operation unit to input a drive command of the motor; a torque setting device that sets an upper limit value of a rotational torque of the output shaft in accordance with a torque setting command; and a control device that drives the motor in one of a forward direction and a reverse direction in accordance with the drive command, and stops driving of the motor when the rotational torque of the output shaft has reached the upper limit value set by the torque setting device during driving of the motor. The torque setting device is configured to set the upper limit value such that the upper limit value during driving of the motor in the forward direction and the upper limit value during driving of the motor in the reverse direction are different.

Abstract: The invention relates to a method for starting an electronic drive circuit for the windings of an electric motor. A control unit, which is connected to a voltage source, is provided as well as a capacitor connected via a system switch element to the connecting terminals of the voltage source. The capacitor is connected across the input terminals parallel to the drive circuit. An operating circuit controls the system switch element. In order to start the motor, the operating circuit closes the system switch element and charges the capacitor and after the charging of the capacitor, opens the system switch element again. A test step is then started by the control unit, the drive circuit being supplied exclusively by the capacitor voltage (UC) during the test step.

Abstract: A method serves for starting a polyphase electric motor which is operated in a star connection. The method conductively bridges at least one winding part of a phase of the motor and electrically disconnects the bridged winding part, in order in this manner, to supply a higher voltage to the remaining, electrically effective windings, and thus to increase the flow of current and thus the torque.

Abstract: The electrical power steering apparatus 10 includes the 1st MOS-FET 13 and the 2nd MOS-FET 14 accommodating the 1st parasitic diode 15 and the 2nd parasitic diode 16 in the conducting path between the battery 100 and the motor driving circuit 11 and being connected in series at the opposite direction respectively, and the condenser 18 in an output side of the latter 2nd MOS-FET 14. The ECU 6 of the controller of the electrical power steering apparatus controls to turn on or off the 1st MOS-FET 13 and the 2nd MOS-FET 14 in accordance with the predetermined sequence after the ignition switch 17 is turned on, detecting the fault of the 1st MOS-FET 13, the 2nd MOS-FET 14 and the 1st parasitic diode 15 and the 2nd parasitic diode 16 on the basis of the output voltage from each of the 1st MOS-FET 13 and the 2nd MOS-FET 14.

Abstract: A thermal stress reduction method includes ramping an electric power generator to start an aircraft engine, for a time period associated with the aircraft engine start sequence toggling a three-level inverter switch array to a three-level pulse width modulation mode, determining if a first time interval in the three-level pulse width modulation mode exceeded a predetermined three-level pulse width modulation mode interval, in response to the first time interval exceeding the three-level pulse width modulation mode interval, toggling the three-level inverter switch array to a two-level pulse width modulation mode, determining if a second time interval in the two-level pulse width modulation mode exceeded a predetermined two-level pulse width modulation mode interval and in response to the second time interval exceeding the two-level pulse width modulation mode interval, toggling the three-level inverter switch array to the three-level pulse width modulation mode.

Abstract: A motor control device including: a following control unit that calculates a pre-correction torque command based on a difference between an operation command signal for commanding an operation of a motor and a detection signal resulting from detecting an operation of the motor; an adder that outputs a post-correction torque command by adding the pre-correction torque command to a correction torque command; and an electric-current control unit that outputs a drive current driving the motor based on the post-correction torque command, wherein the motor control device executes control so that the detection signal matches the operation command signal, and further including: a reference-periodic-signal computation unit; an amplitude/phase estimation unit; and a correction-torque computation unit, so that the correction torque command is updated such that a difference between the correction torque command and the post-correction torque command becomes smaller.

Abstract: A method and device for determining the motor moment constant kM of an electric motor by measuring motor parameters on the running motor. For reduction of the previously considerable measuring effort it is proposed that firstly the generator voltage UEMK produced by the motor is measured, and in that the motor moment constant kM is calculated by division of the generator voltage UEMK and the speed of rotation fMot of the motor, taking into consideration at least one further constant. The method and the device are suitable for DC motors and for 3-phase synchronous motors.

Abstract: A motor drive system includes a first interlock mechanism configured to be activated in response to transition to an operable state of an interruption device, to open an open/close device, a second interlock mechanism configured to be activated in response to transition to an openable state of a case containing a power control unit, to open the open/close device, and a control device. The control device is configured to perform, when the first interlock mechanism is activated, a first process of opening the open/close device after shutting down the power control unit, and to perform, when the second interlock mechanism is activated, a second process of opening the open/close device while driving the power control unit, instead of the first process, depending on a counter electromotive voltage generated by a motor.

Abstract: A rotary electric machine system includes: a stator that has multi-phase stator coils and that generates stator magnetomotive forces based on respective stator currents having different phases supplied to the multi-phase stator coils; a rotor on which rotor coils are wound such that magnetic poles are formed by rotor currents generated in response to the stator magnetomotive forces generated by the stator; a regulating unit that regulates a flow direction of each of the rotor currents to one direction to thereby regulate a polarity of each of the magnetic poles; and a control unit that controls currents supplied to the stator coils on the basis of a target torque. The control unit superimposes a pulse on the stator currents to adjust the ratio of each of the stator currents and each of the rotor currents so as to minimize a copper loss in the stator and the rotor.

Abstract: Provided is a motor control device which realizes automatic adjustment of control of a motor for driving a mechanical load through a simple operation. The motor control device includes: a follow-up control unit (6) for receiving detection information of a detector (3) to output a torque command signal and output a status of motor control of a motor (1) as a control status amount signal, when a command signal regarding the motor control to be output from an upper-level controller is absent; an oscillation detection unit (9) for receiving the control status amount signal and detecting oscillation of a control status amount to output an oscillation detection signal; and an automatic adjustment unit (10) for receiving the oscillation detection signal to monitor a control status of the motor (1) and adjust a control parameter of the follow-up control unit (6) only when abnormality is detected.

Abstract: A power converting apparatus including a power converter that converts a DC voltage into an AC voltage and applies the AC voltage to an AC rotating machine and a control unit that controls the power converter based on an operation command from the outside is provided. The power converting apparatus includes: a first calculating unit that calculates and outputs, from a d-axis current detection value and a q-axis current detection value detected by the AC rotating machine and current command values based on the operation command, first voltage command values to the power converter, magnetic fluxes of the AC rotating machine, and an angular frequency; and a second calculating unit that sets, as an initial value, at least one of the magnetic fluxes and the angular frequency input from the first calculating unit and calculates and outputs second voltage command value to the power converter and an angular frequency.

Abstract: A motor drive system includes an inverter that supplies power to a three-phase motor, and a control unit that, when first stopping and then commencing supply of alternating current to three phases of the three-phase motor, switches from first control to third control and then to second control. The first control places switching elements in the inverter in a non-conduction state, the second control is a PWM control of the switching elements, and the third control places and keeps a switching element of each of an upper arm and a lower arm in the conduction state until commencement of the supply of current. The upper arm corresponds to a phase through which current flows in a direction entering the motor upon commencement of the supply, and the lower arm corresponds to a phase through which current flows in a direction exiting the motor upon commencement of the supply.

Abstract: When a forced commutation mode ends, a switchover to a sensorless control mode is made. The sensorless control mode immediately after the switchover to the sensorless control mode is executed with a power source current maximum value set at a value higher than a rated current value of a motor. The sensorless control mode immediately after the switchover is executed only over a predetermined period of time, and, after a lapse of the predetermined period of time, a steady sensorless control mode is executed. In the steady sensorless control mode, the power source current maximum value is set at a value equal to the rated current value of the motor.

Abstract: A motor control apparatus includes a power converter, a speed controller, and a stop position controller. The power converter outputs a current to drive a motor based on a torque command. The speed controller generates the torque command based on an error between a speed command of the motor and a speed of the motor. The stop position controller calculates an acceleration command to output a predetermined torque after detection of a reference position per revolution of a position detector for a first time during speed control of the motor, generates a torque feed-forward command based on the acceleration command, generates a position command based on the acceleration command, and generates the speed command based on an error between the position command and the motor position to execute position control of the motor.

Abstract: The invention relates to an electric motor having at least two stators disposed coaxially to each other and a rotor, wherein each stator has 2*n poles, with n=1, 2, 3, . . . , wherein each stator has at least one common coil or winding for all poles, wherein each stator has a first and second partial shell, wherein each partial shell has a shell bottom and n poles, wherein each pole is formed as a tooth extending in axial direction or substantially in axial direction and beginning on the shell bottom, wherein with assembled partial shells of a stator the tooth or the teeth of the first partial shell is or are disposed in alternating manner in circumferential direction with the tooth or the teeth of the second partial shell, and wherein with assembled partial shells or a stator, the at least one coil) or winding is received between the partial shells.

Abstract: Some of the embodiments of the present disclosure provide a method comprising detecting, based on a sensor and a back electromagnetic force generated in a rotating device, a speed of the rotating device; and based on (i) the speed detected using the sensor or (ii) the speed detected using the back electromagnetic force, driving the rotating device.

Abstract: A control system for controlling an electrical device of a nacelle, the device having at least one element that is movable to a closed position and an open position. The control system includes at least one electromechanical member for actuating the movable element, a unit for electrically driving the electromechanical actuation member, and a controlling and monitoring unit for controlling the electrical drive unit so as to move the movable element to the closed and/or open position. The control system further includes a system for recovering braking power from the electrical drive unit during the movement of the movable element to the closed and/or open position.

Abstract: An ice dispensing assembly in an appliance and a method of controlling a duct door in an ice dispensing assembly is provided. A duct door is actuated to dispense ice using a motor. The motor can be variably driven using an electrical signal having a plurality of different levels or slopes during the actuation of the duct door. The electrical signal can have an increasing slope when the duct door is actuated into an open position. When the duct door is held in the open position, a constant electrical signal can be applied to the motor. The constant value can be lower than a peak value of the increasing slope of the electrical signal. To return the duct door to a closed position, an electrical signal having a decreasing slope can be applied to the duct door motor.

Abstract: According to an aspect of the present invention, there is provided a power tool including: a motor; a switching device that switches over, in response to a conduction angle thereof, an AC voltage to be applied to the motor; a rotation speed setting unit that sets a target rotation speed of the motor; a rotation speed detection unit that detects an actual rotation speed of the motor; and a controller that determines the conduction angle by comparing the actual rotation speed with the target rotation speed and that controls the switching device by use of the conduction angle based on a maximum conduction angle, the maximum conduction angle being set in accordance with the target rotation speed.

Abstract: During operation of a 3 phase BLDC motor it is driven by use of a PWM waveform applied to one of the driven phase (curve a). The other driven phase is connected thereto but no driving signal is applied (curve b). The third phase is left floating (curve c). This allows the back EMF in the third phase to be monitored for the purpose of determining rotor position by detection of zero crossing points. The rapid switching of the PWM pulses causes ringing in the back EMF signal indicated for one pulse by the ringed portions 1 of curve c. The ringing in the back EMF signal introduces inaccuracy into position calculations derived from back EMF signal measurement. In order to reduce this ringing, in the present invention, a reverse pulse is applied to the other driving coil shown (curve b) prior to a PWM on pulse. The reverse pulse has a polarity such that it drives the phase current through the linked coils in a direction opposite to that caused by the PWM on pulse.

Abstract: An electric power tool includes: a motor; a manipulation input receiving unit which receives a user manipulation input for rotating the motor; a mode changeover unit that has one manipulation portion which manipulated by the user; a rotation drive force transmitting unit that switches a transmission mechanism to one of the transmission mechanisms corresponding to the set position of the manipulation portion and transmits a drive force of the motor to a tool output shaft via the switched transmission mechanism; an electric signal output unit that outputs an electric signal corresponding to the set position of the manipulation portion; and a motor control unit that sets the control method of the motor to a control method preset for the electric signal, among a plurality of different types of control methods, based on the electric signal, and controls the motor by the set control method, based on manipulation by the user.

Abstract: A method and a device for controlling and/or regulating an electric motor. Such electric motors are used for example in motor vehicles in the form of pump motors. In general, the electric motor is supplied with electrical energy from a battery and/or using a generator. The controlling and regulation take place using a high-frequency pulse width modulation (PWM). When the electric motor is started, the PWM is used to continuously increase the motor current required for the operation of the electric motor, e.g. beginning from 0.

Abstract: Diagnosing auxiliary equipment associated with an engine. A condition of the auxiliary equipment is diagnosed based on information provided by signals from a generator operationally connected to the auxiliary equipment or other signals associated with the engine. Different types of degradation are distinguished based on discerning characteristics within the information. Thus, a degraded auxiliary equipment component can be identified in a manner that reduces service induced delay.