Abstract: A direct current motor controlling apparatus may include a direct current motor driving unit to apply a driving voltage to a direct current motor and detect a predetermined signal from the direct current motor, and a servo-micom to control the status of the direct current motor using the signal detected by the direct current motor driving unit. Accordingly, the rotational status of the direct current motor is checked to control the direct current motor.

Abstract: Disclosed is a method for braking or stopping an electromotor which can be operated with direct current, such as a brushless direct current motor. If there is an error in the electromotor or in the electronic or mechanical units connected to the electromotor, the presence of definite error states is verified, and the electromotor is braked, by carrying out, taking into consideration a maximum loading capacity of an electronic control unit which is connected to the electromotor, at least temporarily, a control of the electromotor which is adapted to the detected, definite error state.

Abstract: A programmable robot system includes a robot provided with a number of individual arm sections, where adjacent sections are interconnected by a joint. The system furthermore includes a controllable drive mechanism provided in at least some of the joints and a control system for controlling the drive. The robot system is furthermore provided with user a interface mechanism including a mechanism for programming the robot system, the user interface mechanism being either provided externally to the robot, as an integral part of the robot or as a combination hereof, and a storage mechanism co-operating with the user interface mechanism and the control system for storing information related to the movement and further operations of the robot and optionally for storing information relating to the surroundings.

Abstract: Current source converter (CSC) based motor drives and control techniques are presented in which DC link current is regulated to a level set by the output inverter during dynamic braking operation by pulse width modulation of a braking resistance connection signal to maintain control of motor torque and speed while mitigating or preventing line side regenerative currents.

Abstract: A drive system for an electric drive machine having an engine, a generator, a motor, final drive wheels and auxiliary devices is provided. The drive system may include an inverter circuit and an auxiliary driver. The inverter circuit may be coupled to each of the generator and the motor. The auxiliary driver may be coupled to each of the generator and the auxiliary devices. The inverter circuit and the auxiliary driver may be configured to automatically communicate power from the engine and any power from the auxiliary devices to the motor in a propel mode, and automatically communicate power from the motor to the engine, and optionally to a hybrid system if applicable, in a dynamic braking mode so as to minimize fuel consumption during the dynamic braking mode.

Abstract: A device and system that can dynamically provide variable load on a generator and intelligently distribute generated power to loads and energy storage devices is disclosed. One system includes load profile controllers that employ a switching strategy to dynamically vary the load the generator induces while producing regenerative energy. This switching strategy may allow for a wide dynamic range of configurable damping characteristics, as well as decouple generator damping and the system output power. Multiple load profile controllers can be used together via a communications network, such as a vehicle controller area network (CAN) bus. A central regeneration controller or existing electronic control unit (ECU) can issue commands to change damping performance in different load profile controllers.

Abstract: The present invention provides a unique improvement (23) in an electronic motor drive (20) having an LC filter (21) to reduce conducted emissions from a motor (M) back to a voltage source (V1). The improvement broadly includes diode (24) in series with the inductor (L1) of said filter to prevent transmission of regenerative power from the motor to said voltage source; and a bypass switch (25) arranged in parallel with the diode and selectively operable to enable transmission of regenerative power from the motor to said voltage source.

Abstract: The performance of a power transducer is improved while efficiently using a power semiconductor also by managing the permissible duty factor of the power semiconductor in the regenerative braking circuit provided in the power transducer. The user is allowed to set, through an operation panel provided on the power transducer, the resistance value of the regenerative braking resistor for thermally consuming the rotational energy generated during motor deceleration. The power transducer performs the steps of: calculating the current which flows in the regenerative braking circuit from the resistance value setting; obtaining the generation loss of the power semiconductor in the regenerative braking circuit with the calculated current value; and determining the permissible duty factor of the power semiconductor from the obtained generation loss.

Abstract: A power converter device for achieving a stable braking operation, preventing excessive current to flow therein, when conducting DC braking on a permanent synchronous motor, comprises: a switching circuit for converting DC to AC; a PWM controller means, for controlling ON or OFF of said switching circuit; a means for detecting or estimating current flowing through a permanent magnet synchronous motor; and a means for executing DC braking of said permanent magnet synchronous motor, wherein there are provided a DC braking maximum current setup value, which is determined from an outside or is determined in advance within an inside, and a PWM all-phases cutoff function and a zero vector output function within said PWM controller means, within said PWM controller means, whereby the PWM all-phases cutoff and the zero vector output are repeated within said PWM controller means, if a current value, which is obtained by said means for detecting or estimating the current, exceeds said DC braking maximum current setup v

Abstract: A retarding system for an electric drive machine (100) includes a direct current (DC) link (312), at which a DC voltage is developed, disposed between a rectifier (206) and an inverter (208). A first contactor switch (216) electrically communicates with a first rail of the DC link (312), and a second contactor switch (216) electrically communicates with a second rail of the DC link (312). A first resistor grid (214) is connected in series between the first contactor switch (216) and the second contactor switch (216). The first resistor grid (214) dissipates electrical energy in the form of heat by conducting a current between the first rail and the second rail of the DC link (312) when the first contactor switch (216) and the second contactor switch (216) are closed.

Abstract: Methods and systems for operating an inverter coupled to an electric motor are provided. The inverter has a plurality of high switches and a plurality of low switches coupled to the electric motor. An event indicative of deceleration of the electric motor is detected. The inverter is alternated between a first mode of operation and a second mode of operation during the deceleration of the electric motor. In the first mode of operation, each of the plurality of high switches is activated and each of the plurality of low switches is deactivated. In the second mode of operation, each of the plurality of low switches is activated and each of the plurality of high switches is deactivated.

Abstract: An electric powertrain for use with an engine and a traction device is disclosed. The electric powertrain has a DC motor/generator operable to receive at least a portion of a first mechanical output from the engine and produce a DC power output. The DC motor/generator is also operable to receive DC power and produce a second mechanical output. The electric powertrain further has a drivetrain operable to receive the DC power output and use the DC power output to drive the traction device. The drivetrain is also operable to generate DC power when the traction device is operated in a dynamic braking mode.

Abstract: In a motor control circuit which controls energization of a coil on the basis of a detection result of a rotor position, control is performed so that continuous rotation of the rotor by inertia is suppressed, rotation is stopped quickly, and reverse rotation of the rotor is prevented. When an external control signal CTL is changed from L to H, the normal rotation control is switched to reverse rotation control, and a reverse brake state is effected. When motor rotation speed is monitored and reduced to a set rotation speed, a brake control signal SPSB is changed from L to H, and a short brake state is effected. However, the motor continues to be rotated by its own inertia, and a position detection signal HALL is changed. Thus, reverse brake control is temporarily performed (only during a time period corresponding to a pulse width TRB). The short pulse reverse brake control is intermittently performed until the motor is completely stopped.

Abstract: If it is determined that excess power is generated based on overcharge information of a power storage device, a controller starts an operation of consuming the excess power by an excessive power consuming circuit. The controller counts elapsed time from the time point when the power consuming operation started, and if the counted elapsed time exceeds a minimum on-time set in advance, switches the excessive power consuming circuit from active to inactive state. The minimum on-time is set based on a pattern that is expected to cause generation of excessive regenerative power from an AC electric motor because of abrupt change in running status of an electric powered vehicle mounting a motor drive system.

Abstract: A fan system including a motor with a coil, a storage unit, a driver, and a buffer circuit is provided. The coil module has a first connection terminal and a second connection terminal. The storage unit electrically couples with a voltage source, stores electrical energy when the voltage source is available, and releases the stored electrical energy to carry out a brake operation when the voltage source is unavailable. The driver electrically couples with the first and second connection terminals of the coil module to control a direction of an inductor current passing through the coil module. The buffer circuit electrically couples with the coil module. In the brake operation, the buffer circuit operates to form a transient potential between the first and second connection terminals of the coil module and to consume electrical energy of the inductor current, for gradually stopping the motor in a buffering time period.

Abstract: A braking system for an aircraft provided with undercarriage, wherein an axial-flux reversible electric machine is set between the wheel and the frame of the undercarriage; current-dissipating resistors are provided, which can be connected to the windings of the axial-flux reversible electric machine during rotation of said wheel for dissipating by the Joule effect the induced currents generated by the axial-flux electric machine, which behaves as current generator, and producing a braking effect that slows down the movement of the wheel, thus exerting a braking action.

Abstract: A power supply control device controls a power supply connected to a motor and includes: an AC/DC converter that makes a first DC power supply; a DC/DC converter that makes a second DC power supply out of the first DC power supply; a first rectifying element that allows current to flow from the first DC power supply toward the motor; a second rectifying element that allows current to flow from the first DC power supply toward the DC/DC converter; and a third rectifying element that allows current to flow from the motor toward the DC/DC converter. In this way, a power supply connected to a motor can be suitably controlled.

Abstract: A motor drive device including a converter for a power running operation and a power regenerative operation. The converter has power switching elements, a first power regenerative control unit for controlling the power switching elements in the power regenerative operation by using pulse width modulation signal whose pulse width changes with a value indicated by a command signal; a second power regenerative control unit for controlling the power switching elements in the power regenerative operation to generate respective power regenerative currents in a phase representing the maximum potential among three phases of a three-phase AC power supply and a phase representing the minimum potential among the three phases, and a power regenerative operation switching unit for switching a control of the power switching elements in the power regenerative operation between a control by the first power regenerative control unit and a control by the second power regenerative control unit.

Abstract: The invention relates to a braking apparatus, an electric drive and an elevator system. The braking apparatus comprises an apparatus for dynamic braking, for braking an electric machine with dynamic braking, an input for the control signal of the braking apparatus, and also a controller, for controlling the apparatus for dynamic braking as a response to the aforementioned control signal of the braking apparatus.

Abstract: Methods of dynamic braking include two embodiments with braking circuits for vehicles such as, for example, locomotives which are operable down to very low speeds. These circuits can provide a braking force even at zero locomotive speed.

Abstract: A damper circuit for damping a synchronous servo-motor having at least one winding, at least one main damper resistor, connection means for connecting the main damper resistor in series with the winding, and at least one additional damper cell including at least one additional damper resistor connected in parallel with the main damper resistor via a static switch connected to a control module for controlling the switch as a function of a voltage of the winding. The control module has a shunt in parallel with the main damper resistor. The shunt has an output connected to the control input of the switch and a divider bridge connected to the shunt to form a comparator between the voltage of the winding and a conduction voltage of the shunt.

Abstract: Apparatus for transferring power between an electricity network (UP) operating on alternating-current electricity and a multiphase electric machine (M2, M3), which apparatus comprises low-voltage power cells (CS, C11 . . . CN6) operating on a cascade principle, which power cells comprise a single-phase output connector (OUT), and at least one transformer (TA, T1 . . . TN), comprising for each power cell connected to it a single-phase or multiphase winding dedicated to the specific power cell, which transformer comprises at least one additional winding (WA, WB1 . . . WBN) connected to the same magnetic circuit as the other windings for the purpose of at least one auxiliary circuit, which can be connected to the aforementioned additional winding.

Abstract: In a regenerative braking apparatus that is connected to a power supply apparatus that supplies electric power to a load, and consumes regenerative power regenerated from a load side together with other regenerative braking apparatuses that are connected to the power supply apparatus, an operation-level changing unit calculates, as occasion demands, according to energization time of a consuming unit, a lower limit of an operation level for judging whether an energizing unit should be actuated and changing and outputting the calculated lower limit of the operation level, a comparing unit compares the lower limit of the operation level output from the operation-level changing unit and a monitor output of a monitoring unit, and the energizing unit operates when the monitor output exceeds the lower limit of the operation level by a driving unit.

Abstract: The invention relates to a switch arrangement of an electric motor drive (1). The electric motor drive comprises safety switches (3) determined by the safety of the drive, a controlled mechanical brake (4), a power supply circuit (5) of the brake control, a power converter (6), which power converter comprises a network rectifier (7) and a power rectifier (8) of the motor. The power rectifier of the motor is at least partly implemented with controlled semiconductor switches (9, 10) arranged into a bridge. The power converter comprises an intermediate circuit (11, 12) between the network rectifier and the power rectifier of the motor. The switch arrangement comprises normally-open switches (13, 14) in the intermediate circuit of the power converter (6).

Abstract: The invention relates to a blower apparatus (1) having a blower wheel (4) for generating a blower air flow (50). The blower wheel (4) is arranged in a housing (2), wherein the blower wheel is driven by an electric drive motor (8). A blower tube (6) via which the generated blower air flow (50) is guided connects at an outlet (5). A control unit (17) is provided for controlling the rotational speed of the electric drive motor. For a quick reduction of the blower air flow (50), it is provided that the control unit (17) supports the deceleration of the drive motor (8) through a braking current (I).

Abstract: An actuator comprising a reversible electric motor, which over a gearing, drives an activation element which can move back and forth. The activation element is of the non-self-locking type. Furthermore the motor and gearing are of a non self locking type. A brake holds the activation element in any position, when the electric motor is inactive, said brake can be released by means of a release mechanism. The motor is used as generator when the brake is released and the generator voltage from it is used to adjust the velocity of the activation element. Thus, a quick release is provided, where the activation element can be disengaged and adjusted evading gear and motor, and where the movement of the activation element, during the disengagement, occurs with a controlled velocity.

Abstract: A propulsion system is provided. The system includes: a first propulsion vehicle unit including a first tractive bank having at least one traction motor; a second propulsion vehicle unit including: a second tractive bank having at least one traction motor, a contactor electrically coupling the first propulsion vehicle unit and the second propulsion vehicle unit, and an electrical power modulation device coupled between the first tractive bank and the second tractive bank, the electrical power modulation device having an electrical current threshold that causes the electrical power modulation device to transition to an open state to reduce or prevent transfer of electrical power between the first propulsion unit and the second propulsion unit in response to an electrical current at the electrical power modulation device being above the electrical current threshold.

Abstract: A traction control system for a machine having an electric drive configuration is disclosed. The fraction control system includes an electric motor associated with at least one wheel and adapted to provide braking torque to the wheel. The control system further includes a controller configured to determine a rotational speed of the at least one wheel, compare the rotational speed to an allowable slide threshold, and adjust the braking torque to the at least one wheel during retarding if the speed is less than the allowable slide threshold.

Abstract: Systems and methods are provided for capturing and using power generated by the application of an external force or by an inertial force on a vehicle control device that back-drive or forward-drive an actuator coupled to the control device. An actuator is coupled to a control device configured to apply a force related to operation of a vehicle. A bus is configured to conduct power to the actuator. An actuator control system is configured to receive power from a power source via an electrical bus and direct the power to the actuator. The actuator control system is also configured to monitor an actuator power level to determine when the actuator power level does not meet an anticipated power level. When the actuator power level exceeds the anticipated power level, the excess power generated is directed to an energy storage device. When the actuator power level is less than the anticipated power level, supplemental power is distributed from the energy storage device to the bus.

Abstract: A patient support device of a radiation therapy treatment system includes an electromechanical motor and control system for moving the support device. The control system utilizes regenerative braking concepts, converting the motor into a generator as the support device is moved such that no matter the load, the support device will be moved at a constant speed. The control system also allows for moving of the support device in the powered off situation (i.e., when there is no power to the support device).

Abstract: A motor driving circuit is applied to a motor unit, a pushrod unit, and a load unit. The motor unit is driven by the motor driving circuit. The pushrod unit is driven by the motor unit to lengthen or shorten. The load unit is pushed by the pushrod unit. A relay unit of the motor driving circuit is provided to brake the motor unit, thus raising the self-locking force of the motor unit when the pushrod unit lengthens to the maximum length or shortens to the minimum length, or the power supply is cut off.

Abstract: A system and method are provided for improved dynamic braking in AC motors with an electronic drive, and more particularly to using a current regulation circuit to control the current supplied to the motor to be in phase with the internal EMF voltage of the motor such that the braking torque of the current is maximized per ampere of dynamic braking current when needed to stop the motor in case of a control failure or emergency. A current regulator produces a voltage command to the motor based on the current command input. The motor is still controlled by a d-q current regulator and the q-axis (torque axis) voltage is driven to zero while the d-axis (non-torque axis) is left in current control with a zero current command. This way the motor internal voltage drives a current in the terminals of the motor but the current is in phase with the internal voltage of the motor.

Abstract: This electric safety braking device for an electric traction vehicle may allow the force/speed characteristic of the vehicle to be improved and includes a rotating electromechanical machine with permanent magnets which has at least one coil with electric terminals, a rheostatic electric braking torque production device, and a commutation device which are capable of connecting the electric terminals of the electromechanical machine to the braking torque production device. The electric safety braking device includes at least one inductor is connected in series between the braking torque production device and the electromechanical machine.

Abstract: A system for braking a motor. The system includes at least one resistor and a contactor connected to the at least one resistor and a motor. The system further includes a variable frequency drive electrically connected to the motor, wherein the variable frequency drive comprises a controller operably connected to the contactor, wherein at least a portion of the contactor closes connecting the at least one resistor to the motor in response to a command from the controller. The variable frequency drive is configured such that motor flux levels may be maintained at a relatively high level as motor torque current is reduced, resulting in a consistently high motor flux level as the motor speed decreases.

Abstract: An electric powered vehicle according to the present invention comprises a battery, an electric power converting device, an electric motor, a drive wheel, a control part, an accelerator, a brake, and a rotation sensor. The control part detects the velocity using the rotation sensor. When a first velocity threshold is Vt1, and a second velocity threshold is Vt2, and when the thresholds are Vt1<Vt2, regenerative control is permitted in the case where a running velocity increases to or above the second velocity threshold, and the regenerative control is prohibited in the case where the running velocity falls below the first velocity threshold.

Abstract: The servo motor is controlled by a control signal from a control circuit. A common branch line is separated from a positive common line in accordance with information that a safety door is opened. Thus, a first gate drive circuit group is made inoperative. Then, a second gate drive circuit group is operated to thereby short-circuit the U?, V? and W?phases of the motor to place in a regenerative braking state.

Abstract: A drive system is provided for a utility vehicle and includes an alternating-current (AC) motor for providing a drive torque. An AC motor controller receives a battery voltage signal, throttle pedal position signal, brake pedal position signal, key switch signal, forward/neutral/reverse (FNR) signal, and run/tow signal indicative of the utility vehicle being configured to be driven and being configured to be towed. The AC motor controller generates an AC drive signal for the AC motor, wherein the AC drive signal is based on the battery voltage signal, throttle pedal position signal, brake pedal position signal, key switch signal, FNR signal, and run/tow signal.

Abstract: The performance of a power transducer is improved while efficiently using a power semiconductor also by managing the permissible duty factor of the power semiconductor in the regenerative braking circuit provided in the power transducer. The user is allowed to set, through an operation panel provided on the power transducer, the resistance value of the regenerative braking resistor for thermally consuming the rotational energy generated during motor deceleration. The power transducer performs the steps of: calculating the current which flows in the regenerative braking circuit from the resistance value setting; obtaining the generation loss of the power semiconductor in the regenerative braking circuit with the calculated current value; and determining the permissible duty factor of the power semiconductor from the obtained generation loss.

Abstract: The invention relates to a yarn-tensioning device for producing a specific thread pull on a thread (5) that is unwound from a winding point (7) of a creel (2) and is guided to a warping machine arrangement (1). Said yarn-tensioning device comprises a rotating body (18) which is at least partially wound round by threads and an electric motor (19) which is connected to the rotation body. Said motor (19) is equipped with at least one brake transistor (20) for discharging excess energy produced when the generator of the motor is operated, said brake transistor being able to convert generator energy, arising when the generator is operated, into heat.

Abstract: A motor control circuit that features a smart, two-phase braking operation is presented. The motor control circuit includes a motor drive circuit to apply a brake current to a coil of an external motor for active braking of the motor. The motor control circuit further includes a braking control circuit, coupled to the motor drive circuit and responsive to an externally generated control signal, to control the active braking by the motor drive circuit so that the active braking occurs in two phases. The two phases include a first phase that includes a first portion of the active braking and a second phase that includes back electromotive force (BEMF) voltage sensing and a second portion of the active braking.

Abstract: A drive system for an electrically operated vehicle includes an electric drive unit operable as a motor and as a generator, a first power source circuit with a control device for controllably outputting power, a second chargeable and dischargeable power source circuit having at least one capacitor and which is connected in parallel to the drive unit, an electric intermediate circuit connected to the first and the second power source circuits and to the drive unit, a third chargeable and dischargeable power source circuit with at least one battery and which is connected to the intermediate circuit, a first detection device for detecting an electrical voltage of the intermediate circuit, which detection device is connected to the control device, and a second detection device for detecting a characteristic value of the vehicle speed and which is connected to the control device.

Abstract: In a control system and a method for operating a permanent-magnet electrical machine, when the electrical machine is switched off after one of a functional computer and a monitoring computer of the control system has identified a fault, in order to reduce the braking torque of the electrical machine, which is switched-off but still rotating an output stage of the control system is subjected to a three-phase short circuit if the rotation speed D1 does not fall below a definable limit value GR1 or if a voltage U_DC of the output stage (2) exceeds a limit value Umax, and when the rotation speed D1 is below the definable limit value GR1 and a voltage U_DC of the output stage does not exceed a limit value Umax, all the circuits breakers (2o1, 2o2, 2o3, 2u1, 2u2, 2u3) of the output stage (2) are opened in order to fully disconnect the electrical machine from the output stage.

Abstract: A motor drive includes a dynamic braking circuit for producing a deceleration torque utilizing a braking force caused by a synchronous motor acting as a generator when the synchronous motor is deenergized. The motor drive apparatus is equipped with a dynamic braking circuit fault detection capability, a DC power supply which is obtained by rectifying input AC power, voltage application function for applying a voltage to the windings of the synchronous motor and to the dynamic braking circuit for a predetermined length of time by switching power transistors connected to the DC power supply, current detection unit for detecting the value of a current flowing from the power transistors, and fault checking unit for checking the dynamic braking circuit for the presence or absence of a fault, based on the current value detected by the current detection unit and on a predefined threshold value.

Abstract: A cooling system for a retarding system of an electric drive machine (100) includes a direct current (DC) link having first and second rails. A first resistor grid (214) is selectively placed in circuit between the rails by an automatic switch (216) in response to a switch (216) signal. A second resistor grid (218) is selectively placed in circuit between the rails by a chopper circuit (220) connected in series with the second resistor grid (218). The chopper modulates a current passing therethrough based on a duty cycle. A motor (336) is in parallel electrical connection across a portion of the first resistor grid (214) and operates in response to a motor (336) signal. An electronic controller (400) calculates a net energy during operation and adjusts the switch (216) signal, the duty cycle, and the motor (336) signal to close the automatic electrical switch (216) and operate the motor (336) when the net energy exceeds a threshold value.

Abstract: An electric injection molding machine includes a motor driving circuit for driving a motor, and a delivery pipe. The motor driving circuit includes a rectifier circuit, a switch control circuit, a heater, a direct current (DC) link circuit, and an inverter circuit. The switch control circuit is configured for controlling the motor to output a regenerative current generated in a deceleration period of the motor. The heater is configured for receiving the regenerative current to heat the delivery pipe via the switch control circuit. A micro control unit (MCU) outputs a heat control signal according to the voltage from the DC link circuit to turn on the switch control circuit so as control deceleration of the motor such that a regenerative current from the motor is supplied to the heater to heat the delivery pipe.

Abstract: A self-tuning vibration absorber including a carrier rod assembly having operatively connected thereto a mounting mechanism for mounting the carrier rod assembly to a primary system and a hollow shafted motorized tuning mechanism for tuning a phase difference between vibration of the primary system and vibration of the carrier rod assembly to 90 degrees, the carrier rod assembly further including a detecting mechanism for detecting the vibration of the primary system and the vibration of the carrier rod assembly, and a controller in electrical connection with the detecting mechanism and the tuning means for controlling the tuning mechanism based on the vibration of the primary system and the vibration of the carrier rod assembly detected. A method of vibration dampening, a method of controlling a self-tuning vibration absorber, and a method of reducing hunting motion in railcars.

Abstract: During braking, lower limits are set based on an input limit of a battery and a brake pedal position, and the set lower limits limit regenerative torques output from motors. This prevents an output of an excessive braking force and torque shock caused by a hydraulic brake being not able to follow sudden changes in the regenerative torques output from the motors when the vehicle speed is reduced.

Abstract: A method and device for electrically braking an electric drive in a machine for processing printing material, includes a power electronics connected between the electric drive and a DC voltage intermediate circuit. A further electric braking device is switchable between the electric drive and the power electronics. Upon a failure of a power system, a computer initiates a generator-type braking operation through the power electronics. The further electric braking device is switched on upon the failure of the power electronics.

Abstract: A power converter device for achieving a stable braking operation, preventing excessive current to flow therein, when conducting DC braking on a permanent synchronous motor, comprises: a switching circuit for converting DC to AC; a PWM controller means, for controlling ON or OFF of said switching circuit; a means for detecting or estimating current flowing through a permanent magnet synchronous motor; and a means for executing DC braking of said permanent magnet synchronous motor, wherein there are provided a DC braking maximum current setup value, which is determined from an outside or is determined in advance within an inside, and a PWM all-phases cutoff function and a zero vector output function within said PWM controller means, within said PWM controller means, whereby the PWM all-phases cutoff and the zero vector output are repeated within said PWM controller means, if a current value, which is obtained by said means for detecting or estimating the current, exceeds said DC braking maximum current setup v

Abstract: An electric brake circuit for holding an alternating current motor rotor stationary uses a direct current brake acting on an AC motor rotor. The rotor has at least one groove formed therein positioned for alignment with at least one AC motor pole when switching from an alternating current to DC. The AC induction motor holds the rotor stationary against a heavier load by using the grooved rotor with the grooves formed in the rotor aligning with the AC motor's poles.