A system and method for brake assisted turning are provided. One system includes a pedal operated braking system configured to apply hydraulic brake pressure to brakes of a vehicle when one or more brake pedals are pressed. The system also includes a steer assist braking system configured to apply hydraulic brake pressure to the brakes of the vehicle based at least partly on a steering angle. The system includes hydraulic shut-off circuitry configured to selectively enable and disable operation of the steer assist braking system.

In a pump housing of a motor-vehicle hydraulic assembly, on which at least two inlet-valve openings, at least two outlet-valve openings, at least one high-pressure control valve opening and at least one switchover-valve opening and a pressure-sensor connection are formed. The at least two inlet-valve openings are arranged in a first row, the at least two outlet-valve openings are arranged in a following second row, the pressure sensor connection is arranged in a further following third row, and the at least one high-pressure control valve opening and the at least one switchover valve opening are arranged in a further following fourth row. There are also five embodiments of arrangements of connecting lines and holes in a pump housing for the short connection of the valve openings and connections, and one embodiment with respect to the use of the pump housing according to one of the six embodiments.

When a trailer is pulled by a tow vehicle where the trailer begins to sway to the left and right of the tow vehicle a large sway can result in loss of control of the trailer and or tow vehicle. The field of the present invention is a system and method of controlling a trailer sway which comprises determining the sway of the trailer utilizing an electronic sensor and independently applying the left and or right trailer brakes at varying levels to reduce trailer sway the traditional single braking signal power from the tow vehicle is separated into two independent braking signals for each of the left and right brakes. All brakes are applied whenever the traditional braking signal goes active where trailer battery power is utilized to independently activate the left and or right brakes during trailer sway.

An accumulator of the invention is provided with a safety mechanism for an emergency which releases an internal pressure of the housing to the oil port side so as to prevent the housing from being exploded by the internal pressure of the housing which comes to a higher pressure in an emergency, for example, occurrence of fire disaster. The safety mechanism for the emergency has a taper portion in a corner portion between the tubular portion and the end surface portion of the stay. The taper portion is buckled at its root position in the emergency. In the case that the taper portion is buckled, a pressure releasing flow path is formed between the bellows cap or the retained member and the taper portion as well as the bellows cap or the retained member and the end surface portion come away. The stay can be manufactured only by press molding.

A method is provided for operating a parking brake module that is at least partially integrated into a compressed air generation system in the event of defects, having a control unit, solenoid valves, and a relay valve for aerating and deaerating at least one spring-loaded brake cylinder. A pressure in the parking brake module which is elevated compared to a normal pressure is determined. A constant compressed air delivery is stopped. A reduced switch-off pressure of the compressed air generation system is set. The pressure level in the parking brake module is lowered to the reduced switch-off pressure through repeated activation of the relay valve.

A system for electrical braking of a vehicle comprises a power bus coupled to a first driver associated with a first electromechanical actuator (EMA). The power bus is also coupled to a second driver associated with a second EMA, and the first EMA and the second EMA are associated with a wheel of the vehicle. The power bus provides braking power to the first EMA via the first driver and to the second EMA via the second driver. A normal braking command interface provides a first braking signal to the first driver and a second braking signal to the second driver. An emergency/park brake interface bypasses the normal braking command interface and sends a first emergency/park braking signal to the first driver and a second emergency/park braking signal to the second driver. A sensor measures a current at a single location of the power bus that is proportional to a braking force exerted on the wheel.

Disclosed is a method for operating an electromechanically operable parking brake for motor vehicles with a driving engine furnished with a mechanical gear box, being substantially composed of an operating element, an electronic control unit, to which are sent wheel rotational speed values from wheel rotational speed sensors, at least one unit for generating a brake application force, and brake devices on at least one axle being lockable by the unit, with the electronic control unit actuating the unit after detection of a starting maneuver of the motor vehicle in the sense of a release operation of the parking brake. In order to render a release operation of the parking brake as comfortable as possible after detection of a starting maneuver of the motor vehicle, the method at issued arranges that the electronic control unit (6) actuates the unit (1) in order to reduce the brake application force to an inclination-responsive holding force when a starting maneuver is detected and before the release operation of the parking brake is performed.

An electric driving type utility vehicle having a regenerative brake force distribution control function, and a regenerative brake force distribution control method thereof are provided. The utility vehicle includes: a controller for controlling an output and a recovery of a motor; recovery sensing means for sensing a recovery braking state when the motor is driven; a power measurement unit for measuring the amount of recovery power generated in the recovery braking state; and a power switching unit for automatically switching a drive mode from a two-wheel drive mode to a four-wheel drive mode or vice versa according to the load condition. The present invention can switch the present mode to the four-wheel drive mode by operating the power switching unit according to the control of the controller when sensing the recovery brake through the recovery sensing means in the driving state.

A method for hydraulically boosting a vehicle electric parking brake having a hydraulic service brake and an electric parking brake. Application forces electically generated by the parking brake function is superimposed on the boosting brake force generated by a hydraulic boosting brake pressure provided by the service brake to the brake actuator. When the parking brake is actuated to generate a predetermined application force, the force generated by the brake actuator is detected as the actual value, if an actual value of the measured value is smaller than a first target value a boosting brake pressure value is applied to the brake actuator, and by means of the parking brake function an adjustment function for the tension of the brake actuator to which the hydraulic boosting brake pressure is applied is carried out to achieve the predetermined application force.

A control device for a braking system of a vehicle is provided, having a first receiving device which receives a provided brake activation intensity variable, a plunger control device which determines a setpoint fill level variable of a plunger, taking into account at least the received brake activation intensity variable, and a corresponding plunger control signal is outputtable so that a ratio of an actual volume and a maximum fillable volume of a storage volume of the plunger is settable corresponding to the determined setpoint fill level variable. For a brake activation intensity variable corresponding to a predefined non-activation intensity variable, the plunger control device determines a fill level variable different from an empty state as the setpoint fill level variable, and outputs a plunger control signal corresponding to the determined setpoint fill level variable to the plunger such that the plunger is at least partially filled.

Systems and methods disclosed herein may be useful emergency braking systems for use in, for example, an aircraft. A system is disclosed that allows emergency braking without the need for a manually operated emergency brake. For example, a system is provided comprising a potentiometer in mechanical communication with a brake pedal, a first electronic switch in electrical communication with the potentiometer, a second electronic switch indicating a displacement of the brake pedal, wherein a brake control valve opens in response to the first electronic switch, and wherein a shutoff valve opens in response to the second electronic switch.

A pressure control valve arrangement for controlling a fluid pressure in an ABS brake system of a vehicle so that, while there is a tendency of individual wheels of the vehicle to lock, the brake pressure in at least one associated brake cylinder can be adaptively adjusted, including: a housing; and at least one diaphragm valve is accommodated in the housing, the diaphragm valve having a diaphragm as the valve body, which diaphragm can be acted upon by introducing pressure medium into a control chamber that is covered on the outside of the housing by a cover so that the control chamber is formed between the diaphragm and the cover, wherein at least one pressure medium channel carrying pressure medium is formed in the housing in the region of the cover, wherein at least one cover has at least one projection projecting into the pressure medium channel in the housing, a pressure medium guiding surface for directing the flow of the pressure medium carried in the pressure medium channel being formed on the projection.

A flat, box-shaped hydraulic block for the mechanical fastening and hydraulic interconnection of solenoid valves, pump elements, etc. of a slip-controlled vehicle brake system connects connections of installation spaces for the pump elements to connectors for a brake master cylinder and connections of receptacles for pressure build-up valves which run past one another via flat chambers on longitudinal sides of the hydraulic block and short blind bores. As a result, the receptacles of the pressure build-up valves are connected to the connectors for the brake master cylinder. The chambers damp pressure pulses of the pump elements of a piston pump.

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.

A variable speed power converter controls the speed of a load in a material handling system as a function of the torque required to move the load. While the power converter is running, the torque being produced in the motor is determined. The power converter then determines the maximum rotational speed of the motor as a function of the torque currently being produced and of the torque-speed curve of the motor. The power converter then commands the motor to rotate at this maximum rotational speed. The power converter periodically monitors the torque being produced and adjusts the maximum rotational speed of the motor throughout the run.

A motor control device comprises: an acceleration upper limit estimating unit; a target acceleration setting unit; a motor control unit; and a deficit calculating unit, wherein the target acceleration setting unit corrects the target acceleration based on the acceleration profile by an amount corresponding to the acceleration deficit within a range in which the target acceleration does not exceed the acceleration upper limit on the basis of the acceleration deficit calculated by the deficit calculating unit to set the target acceleration at each time.

To achieve peak acoustic and power performance, the coil or applied current should be in phase or substantially aligned with the back electromotive force (back-EMF) voltage. However, there are generally phase differences between the applied current and back-EMF voltage that are induced by the impedance of the brushless DC motor (which can vary based on conditions, such as temperature and motor speed). Traditionally, compensation for these phase differences was provided manually and on an as-needed basis. Here, however, a system and method are provided that automatically perform a commutation advance by incrementally adjusting a drive signal over successive commutation cycles when the applied current and back-EMF voltage are misaligned.

A driving system for a fan that enables an increase in motor current that may be supplied to excitation windings at the time of a maximum static pressure without increasing the rotational speed excessively when an amount of maximum air flow is provided. The fan driving system includes a drive signal generating circuit that generates drive signals, a motor driving circuit that supplies a motor current to the motor in accordance with the drive signals, a current detecting circuit (resistance) that detects the motor current, and a drive signal changing circuit. The drive signal changing circuit changes the drive signals generated by the drive signal generating circuit to restrict an increase in the motor current when the motor current becomes larger than a threshold.

A motor control apparatus for controlling a DC motor includes a first detection unit configured to detect an angular velocity of the DC motor, a driven member configured to be driven by the DC motor, a control unit configured to perform, during start-up of the DC motor, feed forward control for changing a control value used for controlling drive of the DC motor from a first control value corresponding to an angular velocity smaller than a target angular velocity to a second control value corresponding to the target angular velocity, and to change the feed forward control to feedback control for controlling the control value based on a detection result by the first detection unit to keep the DC motor at the target angular velocity, and a second detection unit configured to detect whether the driven member has been replaced.

An electric motor, having a stator (465), a rotor (470), and an apparatus for evaluating a signal provided for controlling said motor (110), comprises a receiving unit (430, 440) for receiving a control signal (PWM_mod), which is a pulse width modulated signal (PWM) onto which a data signal (DIR, DATA) is modulated. An evaluation unit (440) is provided for evaluating the modulated control signal (PWM_mod). The unit is configured to extract, from the modulated control signal (PWM_mod), data provided for operation of the motor (110). The control apparatus includes a signal generator (450) configured to generate, on the basis of the extracted or ascertained data provided for operation of the motor (110), at least one control signal for the motor (110), such as a commanded direction of rotation. Piggybacking other control data onto the PWM power level signal reduces hardware investment, by permitting omission of a signal lead which would otherwise be required in the motor structure.

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, an output circuit, and a zero-cross-detecting circuit. While measuring 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 a zero cross of an induced voltage, generated across the driving coil, during the de-energized period, the driving-signal-generating circuit determines a length of a subsequent energized period based on the measured driving cycle, when the zero-cross-detecting circuit detects the zero-cross, and the driving-signal-generating circuit determines a length of an immediately previous energized period as a length of a subsequent energized period, when the zero-cross-detecting circuit does not detect the zero-cross.

A system and method for determining the start position of a motor. According to an embodiment, a voltage pulse signal may be generated across a pair of windings in a motor. A current response signal will be generated and based upon the position of the motor, the response signal will be greater in one pulse signal polarity as opposed to an opposite pulse signal polarity. The response signal may be compared for s specific duration of time or until a specific integration threshold has been reached. Further, the response signal may be converted into a digital signal such that a sigma-delta circuit may smooth out glitches more easily. In this manner, the position of the motor may be determined to within 60 electrical degrees during a startup.

The present invention relates to a drive apparatus and drive method for switching an energization mode when a voltage of a non-energized phase of a brushless motor crosses a threshold. In threshold learning, first, the brushless motor is stopped at an initial position. The brushless motor is then rotated by performing phase energization based on the energization mode from the stopped state. The voltage of the non-energized phase at an angular position of switching the energization mode is detected from a maximum value or a minimum value of the voltage of the non-energized phase during the rotation, and the threshold is learned based on the detected voltage. Alternatively, the brushless motor is positioned at the angular position of switching the energization mode by maintaining one energization mode, and then the energization mode is switched to the next energization mode. The voltage of the non-energized phase immediately after the switching to the energization mode is detected, and the detected voltage of the non-energized phase is learned as the threshold used to determine the timing of switching to the next energization mode.

A control circuit for a blender provides low-cost power conditioning through the use of a high resistance which provides temporary power for operation of low-voltage logic circuitry and low-voltage switches for a time sufficient to switch the motor on, and a lower resistance which provides sufficient power for maintaining the motor on state indefinitely as instructed by the low-voltage logic circuitry. Low average power dissipation is provided by powering the low-voltage logic circuitry and low-voltage switches using the high resistance in a standby mode and switching in the lower resistance only when the motor is activated.

A circuit for speed monitoring of an electric motor comprises a circuit for generating a time-frame signal, a circuit for receiving a first signal from a chopper driver circuit designed to drive the electric motor, a circuit for detecting chopper pulses in the first signal, a pulse counter, and a circuit for at least one of outputting and evaluating a state of the pulse counter, after the inactive state of the time-frame has been indicated. The time-frame signal indicates when a time-frame of predefined length changes from an inactive state to an active state and indicates when the time-frame changes back from the active state to the inactive state. The pulse counter is designed to count the detected chopper pulses while the active state is indicated by the circuit for generating the time-frame signal.

A sensorless permanent magnet motor system that prevents negative torque caused by back EMF. The system determines the position of the rotating permanent magnet by monitoring back EMF generated on an inactive coil of the motor system. A snubber circuit is used to prevent the back EMF from causing negative torque on the motor. The voltage of back EMF used to power a logic circuit, such as a microcontroller, that controls the operation of the motor. The microcontroller controls the operation of the motor by detecting back EMF and is also partially powered by the back EMF.

In order to process a motor signal (Ia, Um) of a DC motor (4), in particular of an adjustment drive of a motor vehicle, the armature current (Ia) and the motor voltage (Um) of the DC motor (4) are detected and used for determining the back-emf (E) of the DC motor (4), wherein the determined back-emf (E) is used to generate a useful signal (Sf, SEFL), which is in particular speed-proportional, from the armature current signal (Ia) for position sensing or for evaluating an excess force limitation.

A method and device for controlling an electric motor, in particular a machine tool drive, wherein during a sensorless open-loop control mode of operation of the electric motor the speed and the torque are determined from the motor current and the motor voltage, and the moment of inertia of the electric motor torque are determined from the determined motor current and the determined motor voltage, wherefrom then a control torque is determined, which is then associated with an open-loop torque control value and supplied as the torque setpoint value to a control element for setting the motor current and/or the motor voltage in the open-loop mode of operation. As long as the speed is below a minimum speed, the control element receives as input variable a control or pilot control torque generated from a predefined moment of inertia for a sensorless closed-loop control mode of operation of the electric motor.

A computer-implemented fan control method includes measuring a temperature within a computer system and dynamically selecting a fan speed step in response to the temperature received, wherein the fan speed step is selected from a fan speed table defining a finite number of fan speed steps each having an associated fan speed. A fan is operated at the dynamically selected fan speed step, wherein the fan is positioned to drive air through the computer system where the temperature is being measured. The fan output variation is measured over a prescribed time interval and the fan speed table is automatically modified to change the fan speeds associated with each fan speed step, wherein the fan speeds are changed as a function of the measured fan output variation while continuing to drive the fan.

A voltage regulator for a pair of electric motors has an input for a signal indicative of the desired speed for the motors and a pulse width modulation control circuit device. A control module provides a conditioning signal to the control circuit to output to the motors a square wave voltage having a duty-cycle which varies according to a predetermined function of the signal applied to the input of the regulator. The control circuit device has first and second electronic solid state switches associated with the motor and controlled by the control module.

Embodiments of the present method and system permit an effective method for determining the optimum selection of pulse width modulation polarity and type including determining machine parameters, inputting the machine parameters into a predicted duty cycle module, determining the optimum polarity of the pulse width modulation for a predicted duty cycle based on a pulse width modulation generation algorithm, and determining the optimum type of the pulse width modulation for a predicted duty cycle based on the pulse width modulation generation algorithm.

A lower limit value setting unit (52) variably sets a lower limit value (Vth) of a target voltage (Vh*) in a range of a voltage that is higher than the maximum value of voltages (Vb1, Vb2) of power storage devices and is not affected by a dead time provided for converters, based on temperatures (Tb1, Tb2) and required electric powers (Pb1*, Pb2*). A maximum value selection unit (53) sets the maximum value among the voltages (Vb1, Vb2) of the power storage devices and required voltages (Vm1*, Vm2*) of motor-generators, as the target voltage. A target voltage limiting unit (54) compares the target voltage with the lower limit value (Vth), and if the target voltage is lower than the lower limit value (Vth), the target voltage limiting unit (54) sets the lower limit value (Vth) as the target voltage (Vh*).

A switching element is switched off after having been switched on for only a short time interval called a first predetermined time interval, and a determination is made, based on a mode of a change in a contact point potential (a regeneration voltage) between an electric motor and the switching element when the switching element as switched off, as to whether or not one of the electric motor and the switching element has failed. Next, the switching element is switched on for a time interval called a second predetermined time interval, which is longer than the first predetermined time interval, and a determination is made, based on the magnitude of the contact point potential at that time, as to which one of the electric motor and the switching element has failed. It is thus possible for a failure of the switching element and electric motor to be detected.

A method for monitoring input power to an electronically commutated motor (ECM) is described. The method includes determining, with a processing device, an average input current to the motor, the average input current based on a voltage drop across a shunt resistor in series with the motor, measuring an average input voltage applied to the motor utilizing the processing device, multiplying the average input current by the average voltage to determine an approximate input power, and communicating the average input power to an external interface.

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.

The invention relates to an electric motor assembly, particularly for driving a fan for an engine cooling system and/or an air conditioner of a motor vehicle, comprising an electric motor and a motor control device for activating the electric motor. According to the invention, the motor control device can be adjusted according to a characteristic curve (1,2,3,4) of the electric motor and/or of the fan, and thereby the power and/or rotational speed of the electric motor can be adjusted.

A system to monitor the temperature of power electronic devices in a motor drive includes a base plate defining a planar surface on which the electronic devices and/or circuit boards within the motor drive may be mounted. The power electronic devices are mounted to the base plate through the direct bond copper (DBC). A circuit board is mounted to the base plate which includes a temperature sensor mounted on the circuit board proximate to the power electronic devices. The temperature sensor generates a digital signal corresponding to the temperature measured by the sensor. A copper pad is included between each layer of the circuit board and between the first layer of the circuit board and the sensor. The circuit board also includes vias extending through each layer of the board. The copper pads and vias establish a thermally conductive path between the temperature sensor and the base plate.

The present application discloses a control circuit for a power tool and a method for manipulating the power tool. The control circuit has a detection circuit for battery packs, a calculating control circuit, a battery capacity indicating circuit for indicating the calculation result of the battery capacity, and a current measure and calculating circuit for measuring the current flowing through motors. The calculation result further includes the voltages consumed by the battery pack internally and the discharge loop. The method for manipulating the power tool includes pressing the switch to electrically connect the motor and the battery pack, measuring the parameters of the battery pack and allowing the motor to operate or not according the measured parameters. Further, after the motor is in operation, the battery capacity is calculated and the results are displayed.

Assemblies for HVAC systems and methods of operating HVAC systems are disclosed, including a method of operating an HVAC system having a compressor assembly and a condenser assembly. The compressor assembly includes a compressor having a compressor motor that is susceptible to backspinning and capable of generating electric power when backspinning. The condenser assembly includes a condenser motor operatively coupled to a fan. The condenser assembly is electrically coupled to the compressor assembly. The method includes using the condenser motor as an electric load to dissipate electric power generated by the compressor motor when the compressor motor backspins.

A motor driving apparatus is applied to a fan and motor mechanism and a voltage supply unit. The motor driving apparatus includes a motor driving unit, a voltage division resistor, a first resistor, a first switch unit, a second resistor, a second switch unit, a third resistor, a third switch unit, a transistor switch, and a pulse width modulation unit. The first switch unit, the second switch unit, and the third switch unit are configured to select the rotational speed upper limitation of the fan and motor mechanism for suppressing noise.

An integrated circuit for controlling an electric motor, which has a primary component with a coil and a permanently magnetic secondary component cooperatively connected via an air gap to the primary component, has a semiconductor substrate in which are integrated a microcontroller and/or a pre-amplifier for controlling the coil of the electric motor. For detecting the position of the permanently magnetic secondary component, at least two magnetic field sensors with their measurement axes aligned crosswise relative to each other are integrated in the semiconductor substrate.

A control circuit for a fan includes a fan controller, a switch controller, and a frequency detector. When a pulse-width modulation (PWM) signal output pin of the fan controller outputs PWM signals, the frequency detector outputs a high level signal, connecting an input pin of the switch controller to an output pin of the switch controller. The fan receives the PWM signal. When the PWM signal output pin of the fan controller does not output PWM signals, the frequency detector outputs a low level signal, such that the output pin of the switch controller does not output any signal. In this state, the fan receives a high level signal through a resistor and a power supply, enabling the fan to continue operating.

The invention relates to a method for detecting blocking or sluggishness (M1, M3) of a DC motor (2). The method comprises the following steps: applying a voltage pulse (Uv,t=Os) to the DC motor (2); monitoring a motor current (IMotor) flowing through the DC motor (2); detecting a maximum value of the motor current (IMotor) following the application of the voltage pulse; checking whether a change in the motor current (IMotor) after reaching the maximum value exceeds a specific amount; signalling the blocking or the sluggishness (M1, M3) of the DC motor (2) if the change in the motor current (IMotor) after reaching the maximum value exceeds the specific amount.

An apparatus or method which accepts a burst of pulses at a frequency which may not be tightly controlled and converts this into a trajectory command that is a suitable motion profile for an incremental motor control application. The output of the invention can be a pulse stream that can be fed to an existing incremental pulse input motor drive or the invention can be embedded into a motor drive where its output is a numerical sequence that defines a physically realizable trajectory to be fed to the control circuits and software within the motor drive.

A motor current detection apparatus in the present invention includes: a current detection unit, a first filter, and a second filter. The detection unit detects a conduction current flowing from a battery to a brushless motor and outputs a conduction current signal corresponding to the detected conduction current. The first filter extracts a first current signal which is included in the conduction current signal outputted from the detection unit and is a signal component in a frequency band equal to or lower than a predetermined first cutoff frequency. The second filter extracts a second current signal which is included in the conduction current signal outputted from the detection unit and is a signal component in a predetermined frequency band within a frequency band equal to or lower than a predetermined second cutoff frequency higher than the first cutoff frequency and having the second cutoff frequency as a maximum value.

A control system (128) for controlling a switched reluctance (SR) machine (110) having a rotor (116) and a stator (118) is provided. The control system (128) may include a converter circuit (122) operatively coupled to the stator (118) and including a plurality of switches (132) in selective communication with each phase of the stator (118) and a controller (130) in communication with each of the stator (118) and the converter circuit (122). The controller (130) may be configured to determine a position of the rotor (116) relative to the stator (118), and generate a modulated switching frequency (152) based on the rotor position.

The present invention discloses a controller and a method for improving motor driving efficiency. According to the present invention, multiple control parameters are inputted to the controller so that the controller can adjust timings of PWM driving signals for driving the motor to advance or delay the turned-ON or turned-OFF points, whereby the motor is driven efficiently.

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.

A method for controlling a motor is provided. The method comprises obtaining electrical signals of the motor with a signal unit, the electrical signals comprising a motor torque and an angular velocity, calculating a voltage phase angle of a voltage vector with a calculating component, wherein a command torque, the motor torque, the angular velocity and a voltage amplitude of the voltage vector are inputs of the calculating component, and wherein the voltage phase angle is a variable and the voltage amplitude is a constant. The method further comprises modulating the voltage phase angle and the voltage amplitude to a switching signal for controlling an inverter; converting a direct current voltage to the voltage vector according to the switching signal, and applying the voltage vector to the motor.

A motor driven power steering (MDPS) may include: a vehicle speed sensor configured to sense vehicle speed; a temperature sensor configured to sense a temperature of a power pack; a current sensor configured to sense an amount of current applied to the MDPS; a storage unit configured to store a thermal resistance value based on the vehicle speed with respect to the temperature of the power pack; and a control unit configured to calculate an estimated temperature by reflecting the thermal resistance value based on the vehicle speed with respect to the temperature of the power pack and the current amount applied to the MDPS into a temperature estimation function, and drive a motor according to the calculated estimated temperature.