Tue, 12 May 2015 08:00:00 EDTA wiper device that includes: a wiper motor that swings a wiper blade that is coupled to the wiper motor through a wiper arm to-and-fro over a window pane between an upper return position and a lower return position; and a drive component that gradually increases power supplied to the wiper motor until the rotation speed of the wiper motor reaches a specific speed when the wiper motor has been restarted from a stationary state of the wiper blade between the upper return position and the lower return position.
Tue, 12 May 2015 08:00:00 EDTA circuit configuration for driving an electric motor includes a signal evaluation module, which stores a number of output patterns. An input pattern is specified, and as a function of the input pattern, one of the output patterns is output, by which the electric motor is driven.
Tue, 07 Apr 2015 08:00:00 EDTA system for determining motor speed of a brush DC motor in an apparatus, including a first filter for receiving a substantially DC component of the motor current and parameters corresponding to the brush DC motor, for calculating a speed estimate thereof; an adaptive bandpass filter having a center frequency corresponding to the speed estimate of the first filter, for receiving the motor current and substantially isolating a periodic current fluctuation thereof; a block for determining a frequency of the periodic current fluctuation, the current fluctuation corresponding to motor speed of the brush DC motor. The adaptive bandpass filter uses debounce filtering to reduce rapid filter passband switching, and a run-in period prior to passband switching to obviate transient effects of filter switching.
Tue, 17 Mar 2015 08:00:00 EDTProvided is an apparatus for compensating offset of a current sensor detecting a motor current supplied by an inverter for PWM (Pulse Width Modulation) control of a motor, the apparatus including a current controller providing a PWM signal generated based on the motor current detected by the current sensor to the inverter, calculating an offset using the motor current detected by the current sensor in response to presence and absence of the PWM control of the motor, or offset-compensating the motor current detected by the current sensor.
Tue, 03 Mar 2015 08:00:00 ESTA 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.
Tue, 24 Feb 2015 08:00:00 ESTA 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.
Tue, 24 Feb 2015 08:00:00 ESTThe 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.
Tue, 17 Feb 2015 08:00:00 ESTThe 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.
Tue, 03 Feb 2015 08:00:00 ESTA rotation speed control circuit is disclosed. The rotation speed control circuit includes a temperature-controlled voltage duty generator, a pulse-width signal duty generator, a multiplier and a rotation speed signal generator. The temperature-controlled voltage duty generator converts temperature-controlled voltage to digital temperature-controlled voltage and executes linear interpolation operation according to a first setting data so as to output temperature-controlled voltage duty signal. The pulse-width signal duty generator coverts pulse-width input signal to a digital pulse-width input signal and executes linear interpolation operation according to a second setting data so as to output a pulse-width duty signal. The temperature-controlled voltage duty signal and the pulse-width duty signal are executed for multiplication by the multiplier so as to output mixing-duty signal. The rotation speed generator receives the mixing-duty signal and a third setting data, and executes a minimum output duty operation so as to output a pulse-width output signal.
Tue, 27 Jan 2015 08:00:00 ESTA 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.
Tue, 13 Jan 2015 08:00:00 ESTA 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.
Tue, 06 Jan 2015 08:00:00 ESTAn 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.
Tue, 30 Dec 2014 08:00:00 ESTThe 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.
Tue, 25 Nov 2014 08:00:00 ESTA 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.
Tue, 21 Oct 2014 08:00:00 EDTAn 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.
Tue, 14 Oct 2014 08:00:00 EDTA 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.
Tue, 07 Oct 2014 08:00:00 EDTAssemblies 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.
Tue, 30 Sep 2014 08:00:00 EDTAn 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.
Tue, 23 Sep 2014 08:00:00 EDTThe 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.
Tue, 16 Sep 2014 08:00:00 EDTA detection control system includes a sensing unit, a control module and a driving module for a motor including a rotor and a stator. The sensing unit electrically connects the motor to sense a first and a second magnetic pole of the rotor cross a chip disposed between the rotor and the stator; a third magnetic pole is alternated to a forth magnetic pole of the stator to generate a sensing signal. A detection unit of the control module detects a kickback voltage value generated by a first current value changing to a second current value to calculate a minimum current value to generate a detecting signal. A timing unit receives the sensing and the detecting signal to calculate a first and a second period of time, and a discharging time. The driving module drives the rotor by receiving a control signal the control unit generates by controlling an alternating time.
Tue, 09 Sep 2014 08:00:00 EDTA 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.
Tue, 02 Sep 2014 08:00:00 EDTThe 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.
Tue, 02 Sep 2014 08:00:00 EDTA 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.
Tue, 19 Aug 2014 08:00:00 EDTA 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.
Tue, 12 Aug 2014 08:00:00 EDTA 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.
Tue, 05 Aug 2014 08:00:00 EDTA 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*).
Tue, 05 Aug 2014 08:00:00 EDTEmbodiments 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.
Tue, 05 Aug 2014 08:00:00 EDTA 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.
Tue, 05 Aug 2014 08:00:00 EDTAn 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.
Tue, 15 Jul 2014 08:00:00 EDTA circuit includes a comparator having input terminals configured to be coupled across a drive transistor adapted to drive a phase of a motor. The comparator senses a drive current of the motor phase, said sensed drive current represented by a periodic signal whose period is indicative of motor speed. A motor speed calculation circuit receives the periodic signal and processes the periodic signal to determine a speed of the motor.
Tue, 10 Jun 2014 08:00:00 EDTA 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.
Tue, 27 May 2014 08:00:00 EDTA 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.
Tue, 20 May 2014 08:00:00 EDTA 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.
Tue, 13 May 2014 08:00:00 EDTIn 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.
Tue, 13 May 2014 08:00:00 EDTA 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.
Tue, 06 May 2014 08:00:00 EDTA 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.
Tue, 06 May 2014 08:00:00 EDTA 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.
Tue, 06 May 2014 08:00:00 EDTA variable speed trigger mechanism that allows a user to reverse a direction of a motor and supply variable amounts of power to the motor using a single trigger mechanism. In a first motion, the user can actuate the reversing module to change the direction of the motor coupled to the trigger mechanism. In a second motion, the user can actuate the same trigger and apply variable amounts of power to the motor.
Tue, 29 Apr 2014 08:00:00 EDTThe 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.
Tue, 22 Apr 2014 08:00:00 EDTA 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.
Tue, 08 Apr 2014 08:00:00 EDTElectromotive furniture-flap drive, characterized by an identification device for automatically identifying the type of furniture flap in the installed state of the furniture flap drive.
Tue, 08 Apr 2014 08:00:00 EDTA 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.
Tue, 01 Apr 2014 08:00:00 EDTAn 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.
Tue, 25 Mar 2014 08:00:00 EDTA 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.
Tue, 25 Mar 2014 08:00:00 EDTA 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.
Tue, 25 Mar 2014 08:00:00 EDTTo 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.
Tue, 25 Mar 2014 08:00:00 EDTA 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.
Tue, 18 Mar 2014 08:00:00 EDTAn 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.
Tue, 11 Mar 2014 08:00:00 EDTA 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.
Tue, 18 Feb 2014 08:00:00 ESTA 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.