Abstract: Embodiments herein disclose a method for enabling operation of a single phase induction motor, the method comprising applying space vector Pulse Width Modulation (PWM) to the single phase induction motor; determining pulse width using location of the space vector associated with space vector PWM; and enhancing voltage levels of the single phase induction motor for a particular DC bus voltage using the determined pulse width and the location of the space vector.

Abstract: A method of driving an alternating-current (AC) motor while periodically obtaining a rotator angle of the AC motor. The method includes: (a) driving the AC motor by a dS-axis voltage, which is a voltage for an exciting current in a stationary reference frame, and a qS-axis voltage, which is a voltage for generating a rotational force in the stationary reference frame, while sequentially applying different dS-axis voltages and different qS-axis voltages to the AC motor in a control injection period; and (b) obtaining a rotator angle by a dS-axis voltage value, a qS-axis voltage value, a dS-axis current value, and a qS-axis current value in the control injection period.

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: System and methods for protecting motors of a vehicle are provided. A system includes a current transformer device for each phase of the three-phase power received by each protected motor. Each current transformer device includes a switch that is normally in a first position and is configured to monitor an output current of fuse through which the power is transmitted, compare the output current to a threshold current level, and, when the output current is below the threshold current level, change the switch to a second position. The system also includes a processing circuit configured to control operation of the one or more motors of the vehicle. The processing circuit is configured to determine whether one or more of the switches of the plurality of current transformer devices is in the second position and, if so, activate a fault condition.

Abstract: A command rotation speed is set to an initial rotation speed, and a forced commutation mode is started. In the forced commutation mode, a rotation speed is increased by a predetermined increase amount each time and forced commutation is executed until the rotation speed reaches a set rotation speed. Then, a switchover to the sensorless control mode is made when the rotation speed reaches the set rotation speed (S4) and a rotor position becomes detectable.

Abstract: A system and method for limiting engine starting current of a starter motor of an engine is described. In one example, starter motor current is controlled according to vehicle speed. The method may allow vehicle system voltage to remain at a higher level during automatically initiated engine starts.

Abstract: A method for connecting a second motor to a variable speed drive in parallel with at least one existing motor under load and controlled by the variable speed drive is provided. The method disconnects the existing motor from the variable speed drive and a state estimator calculates transient state of the existing motor including at least the speed of the existing motor based on a previously established load model. The method then connects the second motor to the variable speed drive and the second motor is operated using a suitable directive until the actual state of the second motor attains the calculated transient state of the existing motor at a given time. Upon attaining the calculated transient state, the existing motor is reconnected to the variable speed drive such that no current spike is generated in the aforementioned process.

Abstract: A method for operating an electric vehicle, the electric vehicle having an electric motor and a brake device, and the electric motor and the brake device being capable of being influenced by a control device. When the electric vehicle is at a standstill, when there is an error of the control device, the brake device is actuated so that the electric vehicle cannot move, or at least can move only to a very limited extent.

Abstract: A method and apparatus using electromagnetic switching in a two-step connection process is provided to minimize surge currents and torque oscillations in three-phase motors during starts.

Abstract: Embodiments of the invention provide a starter machine including an electronic control unit. The electronic control unit can be in communication with one or more sensors. The control system can include a starter machine that is in communication with the electronic control unit. The starter machine can comprise a solenoid assembly that includes a plurality of biasing members, a motor that is coupled to a pinion, and power module and controller that is coupled to the motor. In some embodiments, at least one of the power module and the controller are configured to control a speed of the pinion to substantially synchronize the pinion speed and the speed of an engine component.

Abstract: A system for controlling power from an AC voltage to an induction motor to reduce surge when power is restored to a power grid is disclosed including, a device for switching power to the induction motor that has a trigger controllable to enable the device to provide a variable amount of power to the induction motor. The system includes a second device for measuring the AC voltage at the source to determine when power is available, hence determining when the AC voltage is within operating range. Responsive to the AC voltage coming within operating range, the system delays for a time period then initiates power to the induction motor by controlling the device for switching power.

Abstract: The present invention is a resin-encapsulated current limiting reactor that has a number of layers of insulated copper with terminals on each end, and a number of layers of Nomex® fiber insulation wrapped adjacent to each other into a circular or elliptical shape, and encapsulated in polyurethane resin under vacuum.

Abstract: An AC-AC power converter supplies AC power to an AC motor having a plurality of motor windings and a case connected to a ground. The AC-AC power converter architecture includes an asymmetric phase shift autotransformer/rectifier unit (ATRU) that converts an AC input to a DC output, wherein the asymmetric phase shift ATRU generates a common-mode AC voltage across the asymmetric phase shift ATRU. The common mode voltage is diverted to ground through motor case parasitic capacitance via a common-mode voltage pull-down circuit connected between each phase of the ATRU AC input and the ground.

Abstract: Synchronous motors are controlled using a three-phase AC power controller. According to at least one embodiment of the invention, a fundamental wave having the desired frequency is defined for the first phase, and corresponding fundamental waves which have the same frequency as the frequency in the first phase but are out of phase by specific values are defined in the other phases. The triggering times during which the generated current pulse concurrently has the same polarity as the respective fundamental wave in two of the phases are determined for each phase and are used. Two of the three fundamental waves are generated in phase opposition when the desired frequency amounts to half the system frequency.

Abstract: An object of the present invention is providing permissible values of start currents with sufficiently high start torque ensuring the possibility of the start of a loaded motor, the smoothness of the motor's start, without spikes and fluctuations of the currents, voltages and torques. The other objects of the proposed device are simplicity, reliability and economic efficiency. The proposed method of an induction motor start includes an acquisition of two components of the voltage, feeding the motor. The both components have the different controlled frequencies and root mean square values. The proposed device for an induction motor start comprises two channels forming signals, which create two corresponding components of the motor's feeding voltage.

Abstract: A method for controlling operation of a multi-phase induction motor may include transmitting a high-speed operation signal by a master computer for high-speed operation of the motor; receiving the signal by a control signal board, and in response to the signal, the control signal board may sense that the master computer is not simultaneously transmitting a low-speed operation signal, and in response to receiving the high-speed operation signal and not simultaneously receiving the low-speed operation signal, closing delta-to-wye contactors and closing contactors in a power section to transmit power to the motor for high-speed operation, whereby the motor is connected to a source of multi-phase power and operates at high-speed; and the control signal board transmitting a first feedback signal to the master computer that the motor is connected to the source of multi-phase power and is running at high speed.

Abstract: A system and a method for energizing an auxiliary winding of a capacitor-start single-phase induction motor for reducing the voltage level in the bidirectional switches during the blocking of said switches and for providing smooth switching of the electromechanical bidirectional switch. This is achieved by a system for energizing an auxiliary winding of an electric motor, the auxiliary winding being connectable in series with a voltage network, the system including a start capacitor and an electromechanical switch connected in series with the auxiliary winding, the system including an electronic switch connected in parallel with the series association of the electromechanical switch and the start capacitor, the electronic switch and the electromechanical switch being used to turn on the auxiliary winding, the system configured so that the electronic switch can be turned on simultaneously with the electromechanical switch and kept on simultaneously with the electromechanical switch for a stabilization time.

Abstract: A device for improving efficiency of an induction motor soft-starts the motor by applying a power to the motor that is substantially less than the rated power of the motor then gradually increasing the power while monitoring changes in current drawn by the motor, thereby detecting when maximum efficiency is found. Once maximum efficiency is found, the nominal motor current is found and operating ranges are set. Now, the phase angle between the voltage and the current to the motor is measured and power to the motor is increasing when the phase angle is less than a minimum phase angle (determined during soft-start) and power to the motor is decreased when the phase angle is greater than or equal to the minimum phase angle as long as the voltage does not fall below a minimum voltage determined during soft-start.

Abstract: The present invention includes an induction motor soft starter that includes a bypass contactor loop on which is disposed two anti-parallel connected SCRs and a current limiting reactor that limits the current rise during the switching on of the SCRs.

Abstract: A method for determining the angular position of a synchronous machine having a magnetically anisotropic rotor includes an (m) iteration stage and an (n) iteration stage. The (m) iteration stage encompasses: generating an (m) magnetic field of an (m) angular direction and acquiring an (m) peak value of the current pulse generated by the (m) voltage pulse; and providing at least two further (m+i) peak values in different (m+i) angular directions that differ from the (m) angular direction. The (n) iteration stage includes: ascertaining the angular directions (n) and (n+1) in which the two highest or the two lowest peak values from a peak value group occur; and providing an (n) angular direction, which resides between the (n+1) angular direction and the (n+2) angular direction, as an angular position output.

Abstract: A mechanism for a motor controller for engaging a spinning motor is provided. A power section is configured to provide power to the motor. A control is configured to control the power section. The control is configured to search for a motor frequency of the motor by applying a small excitation voltage to the motor, and the excitation voltage is initially applied at a voltage frequency which is a maximum frequency. The control is configured to track the motor frequency until the motor frequency is below an equivalent speed command and engage the motor by applying a higher voltage to the motor.

Abstract: Method and device for starting a motor (12) in weak grids, especially asynchronous motors, which motor after start-up is supplied by a supply grid (13). The device (11) includes a frequency converter (14), which is rated in relation to the size of the motor (12) and arranged to bring the motor (12) up in speed, arranged to synchronize output voltage with voltage from the supply grid (13), and arranged for connecting the motor (12) to the supply grid (13) after the voltage of the motor is synchronized with the voltage of the supply grid (13). The main object is to do this with as low costs as possible and in the most space-saving manner.

Abstract: A device for improving efficiency of an induction motor soft-starts the motor by applying a power to the motor that is substantially less than the rated power of the motor then gradually increasing the power while monitoring changes in current drawn by the motor, thereby detecting when maximum efficiency is found. Once maximum efficiency is found, the nominal motor current is found and operating ranges are set. Now, the phase angle between the voltage and the current to the motor is measured and power to the motor is increasing when the phase angle is less than a minimum phase angle (determined during soft-start) and power to the motor is decreased when the phase angle is greater than or equal to the minimum phase angle as long as the voltage does not fall below a minimum voltage determined during soft-start.

Abstract: A blower motor assembly having a variable speed motor that is suitable for direct, drop-in replacement in a residential HVAC (heating, ventilation, and air conditioning) system that employs a PSC motor. The blower motor assembly includes at least a neutral input and two hot AC line connections, one for connection to the heating power source and the other to the cooling power source. A sensing circuit senses which of the inputs is energized by sensing either voltage or current on the inputs. The sensing circuit delivers a corresponding signal to a motor controller to control the speed of the variable speed motor. The blower motor assembly may also be equipped with additional hot AC inputs, more than one neutral line, and several sensing circuits for sensing current or voltage in the hot inputs and/or the neutral lines for controlling various aspects of the variable speed motor.

Abstract: A relay is provided in a power supply line from a battery to a motor of a starter in a vehicle. The relay is selectively switched between a contact side state where contacts short-circuit and a resistor side state where the contacts open and a resistor is inserted into the power supply line in series. When an engine is started, an ECU controlling the starter energizes the motor by driving the relay to the resistor side only for a first predetermined time in order to suppress inrush current and voltage fall due to the inrush current. The ECU detects a contact side state fixation abnormality of the relay based on a battery voltage at the time when the motor is energized by driving the relay to the resistor side.

Abstract: An inverter for an electric vehicle includes a speed instruction generating unit, a frequency voltage converting unit, an integrator and a 2-to-3 phase converter. The speed instruction generating unit outputs a speed instruction for changing the rotational frequency of an electric motor based on the on/off of a signal outputted from the accelerator pedal. The frequency voltage converting unit outputs a voltage instruction based on the frequency of the speed instruction. The integrator outputs a rotational angle by performing integration on the frequency of the speed instruction. The 2-to-3 phase converter receives the voltage instruction and the rotational angle and converts the received voltage instruction and rotational angle into three-phase voltage instructions.

Abstract: A system for controlling operation of a motor drive during fast start-up of an induction motor is disclosed. The system includes an AC motor drive having a PWM inverter and a control system to generate a command signal to cause the PWM inverter to control an output of the AC motor drive. The control system includes a start-up modulator that is selectively operable during start-up acceleration of the AC motor, the start-up modulator programmed to determine a motor current applied to the AC motor and a voltage of a DC bus, generate a first frequency offset that causes a frequency reference of the command signal to be decreased when the motor current is greater than a reference current threshold, and generate a second frequency offset that causes the frequency reference of the command signal to be increased when the DC bus voltage is greater than a reference voltage threshold.

Abstract: A fan motor control device for controlling the soft start of a fan motor is disclosed. The fan motor control device comprises a converter, a starting capacitor, and a controller. The converter sends out a control signal to the controller based on an input pulse-width modulation signal. The starting capacitor is coupled between a voltage source terminal and a controlled terminal of the controller. Thereby, based on an input voltage to the controlled terminal, the controller controls the soft start of the fan motor. For the soft start period, the magnitude of the input voltage is determined by the base working voltage outputted via the voltage source terminal. While for normal operation, based on the input voltage to the controlled terminal, the controller controls the speed of the fan motor, with the magnitude of the input voltage determined by the control voltage outputted by the converter.

Abstract: A method and an arrangement for determining the rotation speed of a motor fed by an inverter, the arrangement comprising means for determining the rotation speed of the motor in at least two alternative manners, whereby the means for determining the rotation speed of the motor comprise one of the at least two alternative manners of performance: means for measuring the frequency of the voltage fed to the motor by the inverter; and means for estimating the rotation speed of the motor on the basis of the measured frequency.

Abstract: A control circuit for a single-phase AC motor of a dryer, including at least an electronic starting circuit including at least a starting control unit, a first drive circuit, and a bidirectional triode thyristor, a second drive circuit, and a mechanical switch K. The bidirectional triode thyristor is serially connected to a starting winding and a starting capacitor of the motor, and connected to an AC input. The starting control unit is connected to a control end of the bidirectional triode thyristor via the first drive circuit. The mechanical switch K is serially connected to an electrical heating wire, and is connected to the AC input. The starting control unit is connected to a control end of the mechanical switch K via the second drive circuit. The first drive circuit and the second drive circuit are interlocked with each other.

Abstract: Entry of a synchronous speed of a rotor can be facilitated by increasing a starting torque by adjusting a magnetization application time for magnetizing the rotor according to whether or not a starting capacitor is used. The present invention includes: a control unit that outputs a control signal for controlling an application time of a magnetizing current according to whether or not a starting capacitor is used; and a switch that supplies power to an exciting coil according to the control signal outputted from the control unit.

Abstract: A softstarter for starting and stopping an asynchronous motor having three phases, including two pairs of semiconductor devices of the type turning off at zero-crossing of the current therethrough, wherein each of the two pairs of semiconductor devices is connected in anti-parallel, and the first pair of the semiconductor devices is adapted to control the voltage of one of the phases of the motor and the second pair of the semiconductor devices being adapted to control the voltage of another of the phases of the motor, a DC reducing unit associated with the two pairs of semiconductor devices, a first voltage measuring unit for measuring voltages across the two pairs of semiconductor devices, and a first zero-crossing detecting unit configured for detecting zero-crossings of the measured voltages across the two pairs of semiconductor devices and providing zero-crossing signals to the DC reducing unit.

Abstract: A method for controlling a motor is described. The method includes configuring a current sensor to sense a current supplied to the motor from at least one of a plurality of power lines and to generate at least one current signal indicative of the sensed current. The method also includes coupling a processing device to the current sensor such that the processing device receives the current signal. The method also includes configuring the processing device to determine which of the plurality of power lines is active based at least partially on the current signal and generate a motor speed control signal that directs the motor to operate at the motor speed that corresponds to the active power line.

Abstract: A vehicle having a vehicle system is provided with a motor having a housing and a stator. The motor is configured to provide motor torque for vehicle propulsion. The vehicle system is also provided with at least one controller that is configured to receive input indicative of at least one of the housing temperature and the stator temperature, and control the motor torque based on a comparison of the input to predetermined thermal data.

Abstract: A method for controlling a self-piloted alternator-starter for starting or restarting the thermal engine of an automobile. The alternator-starter includes a rotor rotating in a stator, and a belt for transmitting the torque of the alternator-starter rotor to the crankshaft of the thermal engine. The method includes a first preflux step during which the rotor winding is excited by a preflux electric current, and a second starting step during which the stator windings are excited. The preflux step lasts from 10 to 100 ms so that the transmission belt is tensioned below a degradation tension at the start of the second starting step.

Abstract: A blower motor assembly having a variable speed motor that is suitable for direct, drop-in replacement in a residential HVAC (heating, ventilation, and air conditioning) system that employs a PSC motor. The blower motor assembly includes at least a neutral input and two hot AC line connections, one for connection to the heating power source and the other to the cooling power source. A sensing circuit senses which of the inputs is energized by sensing either voltage or current on the inputs. The sensing circuit delivers a corresponding signal to a motor controller to control the speed of the variable speed motor. The blower motor assembly may also be equipped with additional hot AC inputs, more than one neutral line, and several sensing circuits for sensing current or voltage in the hot inputs and/or the neutral lines for controlling various aspects of the variable speed motor.

Abstract: A blower motor assembly having a variable speed motor that is suitable for direct, drop-in replacement in a residential HVAC (heating, ventilation, and air conditioning) system that employs a PSC motor. The blower motor assembly includes at least a neutral input and two hot AC line connections, one for connection to the heating power source and the other to the cooling power source. A sensing circuit senses which of the inputs is energized by sensing either voltage or current on the inputs. The sensing circuit delivers a corresponding signal to a motor controller to control the speed of the variable speed motor. The blower motor assembly may also be equipped with additional hot AC inputs, more than one neutral line, and several sensing circuits for sensing current or voltage in the hot inputs and/or the neutral lines for controlling various aspects of the variable speed motor.

Abstract: A system and method for controlling an AC motor drive includes a control system programmed with an energy algorithm configured to optimize operation of the motor drive. Specifically, the control system receives input of an initial voltage-frequency command to the AC motor drive, receives a real-time output of the AC motor drive generated according to the initial voltage-frequency command, and determines a real-time value of a motor parameter based on the real-time output of the AC motor drive. The control system also inputs a plurality of modified voltage-frequency commands to the AC motor drive, determines the real-time value of the motor parameter corresponding to each of the plurality of modified voltage-frequency commands, and identifies an optimal value of the motor parameter based on the real-time values of the motor parameter.

Abstract: An apparatus operable in a wet environment includes a voltage doubler circuit including a pair of diodes, a pair of direct current switching elements connected between the respective diodes and a common point, a controller, an interface connected to the controller for receiving external status signals, and a switching arrangement responsive to signals from the controller to select the full power mode or a controlled power mode. In the controlled power mode, the switching elements are switched in a predetermined sequence such that only one of the switching elements conducts current during any one half cycle of the AC output voltage applied to the motor.

Abstract: A softstarter for starting and stopping an asynchronous motor having three phases, including two pairs of semiconductor devices of the type turning off at zero-crossing of the current therethrough, wherein each of the two pairs of semiconductor devices is connected in anti-parallel, and the first pair of the semiconductor devices is adapted to control the voltage of one of the phases of the motor and the second pair of the semiconductor devices being adapted to control the voltage of another of the phases of the motor, a DC reducing unit associated with the two pairs of semiconductor devices, a first voltage measuring unit for measuring voltages across the two pairs of semiconductor devices, and a first zero-crossing detecting unit configured for detecting zero-crossings of the measured voltages across the two pairs of semiconductor devices and providing zero-crossing signals to the DC reducing unit.

Abstract: A single-phase AC motor control circuit for a dryer, including a starting control unit, a first drive circuit, a bidirectional triode thyristor BCR1, a second drive circuit, and a bidirectional triode thyristor BCR2. The bidirectional triode thyristor BCR1 is serially connected to a motor starting winding, and a starting capacitor, and then to a utility power AC input. The starting control unit is connected to a control end of the bidirectional triode thyristor BCR1 via the first drive circuit. The bidirectional triode thyristor BCR2 is serially connected to an electrically heated strip, and then to the utility power AC input. The starting control unit is connected to a control end of the bidirectional triode thyristor BCR2 via the second drive circuit. The first drive circuit is interlocked with the second drive circuit.

Abstract: A device for improving efficiency of an induction motor that soft-starts the motor by applying a voltage to the motor that is substantially less than the rated voltage then gradually increasing the voltage while monitoring changes in current drawn by the motor, thereby detecting when maximum efficiency is found. Once maximum efficiency is found, the nominal motor current is found and operating ranges are set. Now, the voltage to the motor is increased/decreased by measuring the phase angle between the voltage and the current to the motor and increasing the voltage when the phase angle is less than a minimum phase angle (determined during soft-start) and decreasing the voltage when the phase angle is greater than or equal to the minimum phase angle as long as the voltage does not fall below a minimum voltage determined during soft-start.

Abstract: A DC motor is provided. The DC motor prevents rush or overload of current in the DC motor during and/or after power input irregularities to the DC motor. A control circuit of the DC motor is configured to control current provided to the DC motor. When power irregularities in the power input to the DC motor are detected by the control circuit, the control circuit stops generating PWM (Pulse Width Modulated) signals and stops the current provided to the DC motor. After the stoppage of PWM signals, the control circuit can perform a soft-start of the PWM signals when the power irregularities are no longer detected. The soft starting of the PWM signals generates gradual increase in current to the DC motor, thus, preventing sudden rush of current that cause malfunction of the DC motor.

Abstract: Systems, methods, and devices are disclosed, including an induction-motor controller having a phase path; a solid-state switch interposed on the phase path; and a controller coupled to the solid-state switch. In certain embodiments, the controller is configured to switch the solid-state switch so that the solid-state switch is conductive during a conduction angle of a cycle of an incoming AC power waveform conveyed by the phase path, calculate the conduction angle based on a generally sinusoidal reference value that has a frequency lower than a frequency of the incoming AC power waveform, and adjust the generally sinusoidal reference value based on a value indicative of flux in a load coupled to the phase path.

Abstract: An electrical switching apparatus includes a plurality of poles each having a Rogowski coil and a conductor passing through an opening thereof, and a processor circuit including a sensor circuit including a plurality of inputs each electrically interconnected with an output of the Rogowski coil of a corresponding pole. The sensor circuit further includes a number of outputs having values each corresponding to current flowing through the conductor, a memory including for each corresponding pole an offset value and a gain correction factor for the sensor circuit, and a gain correction factor for the Rogowski coil, a number of routines, and a processor cooperating with the sensor circuit and the routines to provide for each pole a corrected current value as a function of a corresponding one of the values, the sensor circuit offset value and gain correction factor, and the Rogowski coil gain correction factor.

Abstract: A starting circuit for a single-phase AC motor, the single-phase AC motor comprising a main winding and a starting winding, and the starting circuit comprising a detecting circuit, a rectifying circuit, a triggering circuit, and a switch, wherein the detecting circuit is connected in series with the main winding, the switch is connected in series with the starting winding, the detecting circuit transfers current parameters of the main winding into detecting signals, the rectifying circuit processes the detecting signals and transmits the detecting signals to the triggering circuit, the triggering circuit controls the switch according to the detecting signals whereby controlling power-on and power-off of the starting winding, and the triggering circuit is a hysteresis comparing circuit.

Abstract: Starting device for electric motors provides a circuit including: a first branch connected at one end to a common point and at the opposite end to the start winding of the motor, whereon a starting capacitor, a resistor and fixed contacts of a relay are inserted in series respectively; a second branch in parallel with the first branch, connected at one end to the common point and at the opposite end to the main or run winding of the motors whereon the coil of the relay is inserted; a third branch in parallel with the branches and, connected at one end to the common point and at the opposite end to the start winding of the motor, whereon a run capacitor is installed, this common point being connected to the common connector of the motor via the power supply line.

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

Abstract: A method for starting a brushless DC motor. A rotor is aligned with a stator in accordance with a predetermined phase. After alignment, the rotor is positioned in accordance with another phase, two phases are skipped, a timer is set to a first count time, and the rotor is aligned with the stator in accordance with a third phase. Then the timer is restarted and the rotor is aligned with the stator in accordance with a fourth phase. After a first delay, first back electromotive force value is stored. The timer is stopped when the first back electromotive force value substantially equals a peak amplitude of opposite polarity. The timer is updated to a second count time that is substantially equal to a time at which the second timer was stopped. The process is repeated until the rotor has a position and a velocity that are suitable for normal operation.

Abstract: A method for controlling an electric motor with a softstarter. A softstarter device for control of electric motors. Motor torque is controlled in dependence of a torque error signal, based on a calculated difference between the motor torque and a reference torque value, so that the motor torque displays a rate of change with respect to time, during a stopping or starting time interval, that is adapted to follow a rate of change of the reference torque value, with respect to time, that varies between at least a first part of the time interval and a second part of the time interval, and thereby changing the speed of the motor. A system includes an electric motor, a device driven by the electric motor and a softstarter device for controlling the electric motor. A computer program product includes a computer readable medium and a computer program recorded thereon.