Abstract: A MG-ECU is provided in a hybrid vehicle having an MG and an engine and starts the engine by controlling the MG. When the MG-ECU detects a disconnection in any one of three-phase power supply wires, which supply the MG with power, the MG-ECU permits driving of the MG on condition that the engine is requested to be started. The MG-ECU limits a command torque for the MG is limited to be equal to or less than a predetermined torque value than in a case of presence of no disconnection, when the MG is permitted to be driven.

Abstract: A sensorless control apparatus may include: a speed command unit configured to output a speed command to an electric motor; a current detector unit configured to detect electric current flowing through the electric motor if a voltage being output according to the speed command is supplied to the electric motor; a rotor angle calculation unit configured to calculate a magnetic flux of a rotor of the electric motor based on the detected electric current and the voltage being output according to the speed command, and to calculate an angle of the rotor from the calculated magnetic flux; and/or an out-of-step sensing unit configured to sense an out-of-step of the rotor according to a comparison of the calculated angle of the rotor with an angle of the rotor estimated based on a sensorless control algorithm.

Abstract: A motor control system includes an inverter and a plurality of current sensors each positioned in-line between the inverter and a phase coil of the motor. Each current sensor measures the current provided to each phase coil of the motor and provides a signal indicative of each phase current to a controller. In some embodiments, the currents sensors are provided as one or more current sense integrated circuits. A protection circuit protects the current sense integrated circuit from ground bounce by coupling a diode and an opposite facing Zener diode in series between the power supply pin and the ground pin of the integrated circuit.

Abstract: A system for controlling a brushless motor includes drive circuitry in communication with the brushless motor and a primary control device in communication with the drive circuitry. The system also includes a secondary control device in communication with the drive circuitry and a multiplexer for selectively providing an output of the primary control device or an output of the secondary control device to the drive circuitry, wherein the output of the primary control device is provided to the drive circuitry when the primary control device is operating normally.

Abstract: A control device for a three-phase alternate current motor includes: an inverter for driving the motor; current sensors for sensing current in the motor; and a control means having a feedback control operation part for operating a voltage command of each phase and switching the inverter based on the voltage command. When an absolute value of a sum of the current sensed values of three phases is larger than a threshold, the control means: executes a provisional current sensor system abnormality determination; generates a variation visualizing state, in which a response of a feedback control with respect to a variation in the current sensed value caused by the abnormality is delayed or stopped; and performs a phase identification processing for identifying the current sensor on a phase, in which an absolute value of a current deviation is larger than a threshold.

Abstract: An electric power steering system includes short-circuit determination means for determining whether a short-circuit between an energization failure phase and one of the two phases other than the energization failure phase has occurred while assist force is being generated using the two phases other than the energization failure phase as energization phases. When the short-circuit determination means determines that the short-circuit has occurred, generation of the assist force is stopped.

Abstract: A wireless phasing voltmeter determines the phase difference between the voltage carried by a reference electrical conductor and a field conductor. The voltage signal from the reference conductor is detected by a first unit and compared to a precision 60 Hz wave form generated from a first 1 pps GPS signal. The phase difference between the wave form and the reference conductor, represented by nine data bits, is used to modulate a radio frequency carrier wave and transmitted via simplex transmission to a second unit near an electrical conductor in the field. The second unit receives the modulated carrier wave, decodes the phase angle difference and compares it to a second phase angle difference between the voltage on the field conductor and a second precision 60 Hz wave form generated from a second 1 pps GPS signal. The difference between the two phase differences determines the phase of the field conductor.

Abstract: A control device of a three-phase AC motor includes: an inverter that drives the AC motor; a current sensor that senses a current flowing in a sensor phase of the AC motor as a sensor phase current; and a controller that switches on and off a switching element of the inverter to control a current flowing through the AC motor. The controller includes: a current estimation device that estimates d-axis and q-axis current estimated values based on the sensor phase current and an electric angle of the AC motor; and a zero-crossing interpolation device that interpolates a command value relating to a voltage of the AC motor when the sensor phase current is in a zero cross range, which includes a zero point. When the sensor phase current is in the zero cross range, the zero-crossing interpolation device interpolates the command value with a continuous variable value.

Abstract: The invention relates to a method for operating a multiphase electrical machine (2) in the event of a fault, wherein the electrical machine (2) is driven with the aid of a driver circuit (3), wherein the driver circuit (3) has half-bridge circuits (31), each associated with a phase (U, V, W), and bridge paths (32) for connecting or disconnecting predetermined voltage potentials to/from the respective phases (U, V, W) of the electrical machine (2), wherein one or more of the bridge paths (32) are operated according to a first fault operating mode if a fault is detected, wherein, in the first fault operating mode, the one or more bridge paths (32) are controlled in such a manner that said paths connect a first of the predetermined voltage potentials to the phase (U, V, W) via a predetermined electrical resistor.

Abstract: A control device of a three-phase AC motor includes: an inverter for driving the motor; a current sensor for sensing a sensor phase current of the motor; and a controller for controlling the motor. The controller includes: a current estimation device for estimating d-axis and q-axis current estimated values based on the sensor phase current and an electric angle of the motor; and a zero-crossing interpolation device for interpolating the d-axis and q-axis current estimated values by fixing the d-axis and q-axis current estimated values when the sensor phase current is in a zero cross range, which includes a zero point, so that the sensor phase current crosses the zero point, and for outputting interpolated d-axis and q-axis current estimated values as fixed d-axis and q-axis values, which are used for a feedback control relating to current flowing through the motor.

Abstract: A control device for a three-phase alternate current motor, includes: a control phase current acquisition means; a monitor phase current acquisition means; a rotation angle acquisition means; a two-phase control current value current calculation means; a one-phase current estimated value estimation means; a voltage command value calculation means; an other phase current estimation means for calculating a monitor or a control phase current estimated value; an abnormality detection means for detecting an abnormality in a monitor phase or a control phase current sensor; and a switching means for switching between a monitoring stop mode, in which the voltage command value is calculated based on the two-phase control current value, and a monitoring mode, in which the voltage command value is calculated based on the one-phase current estimated value, and the abnormality detection means detects the abnormality, at predetermined time intervals.

Abstract: In hybrid construction machine employing a hydraulic motor and an electric motor for the driving of the swing structure, satisfactory operability of a combined operation of the swing structure and other actuators is secured irrespective of the operating status of the electric motor. A control device of the hybrid construction machine executes control selected from: hydraulic/electric complex swing control for driving the swing structure by total torque of the electric motor and the hydraulic motor when a swing operating lever device is operated; and hydraulic solo swing control for driving the swing structure by the torque of the hydraulic motor alone when the swing operating lever device is operated.

Abstract: A control device for a three-phase alternate current motor includes: a control phase current acquisition means; a monitor phase current acquisition means; a rotation angle acquisition means; a two-phase control current value calculation means; a one-phase current estimated value estimation means; a voltage command value calculation means; an other phase current estimation means for calculating a monitor or a control phase current estimated value; an abnormality detection means for detecting an abnormality in a monitor phase or a control phase current sensor; a number-of-revolutions calculation means for the motor; a number-of-revolutions determination means for determining whether the number of revolutions is not larger than a predetermined determination value; and a switching means between a two-phase control mode when the number of revolutions is not larger than the determination value and a one-phase control mode when the number of revolutions is larger than the determination value.

Abstract: An inverter device includes a switch circuit configured by series-connecting two N-channel semiconductor switching elements in opposite directions so that the switch circuit makes or breaks electrical connection between a DC power supply and an inverter circuit and a control circuit carrying out a protecting operation in which when the control circuit output a control signal to control switching of the inverter circuit and an operating condition is met, the control circuit stops output of the control signal to turn off all switching elements configuring the inverter circuit and the switch circuit. In the protecting operation, the switch circuit is turned off after output of the control signal has been stopped.

Abstract: A SBW-ECU prohibits driving of an electric motor by turning off power supply to the motor by a drive prohibition device, when a diagnosis part of a by-wire control circuit determines that a shift-by-wire system is abnormal or a monitor circuit determines that the by-wire control circuit is abnormal. In this case, the motor is stopped from rotating by execution of power supply phase fixation processing, by which a power supply phase of the motor is fixed without switchover, when the motor is driven to rotate at the time of determination of abnormality of the shift-by-wire system. Then the prohibition device prohibits driving of the motor by stopping the power supply to the motor.

Abstract: A method for ascertaining the rotor temperature of a permanent-magnet synchronous machine (10), in which a first estimate (TR1) for the rotor temperature is ascertained as a function of a remanent flux density of permanent magnets contained in a rotor of the synchronous machine (10). A second estimate (TR2) for the rotor temperature is ascertained via a Kalman filter containing a thermal model of the synchronous machine (10), the first estimate (TR1) for the rotor temperature being supplied at least intermittently to the Kalman filter.

Abstract: Disclosed are a method and system for detecting a fault of a parallel coil type permanent magnet motor. This method includes driving a parallel coil type motor on the basis of a pre-defined current reference value, detecting a phase current vector of the motor, and calculating a current compensation value for removing a negative sequence component of the motor on the basis of the phase current vector.

Abstract: Disclosed herein are a parallel structure power apparatus and a control method thereof. There are provided a parallel structure power apparatus, including: an alternating current-direct current (AC-DC) converting unit, a main driving unit, a sub-driving unit, a temperature sensor unit measuring and outputting a temperature of the main driving unit and the sub-driving unit, and a controlling unit separately controlling the main driving unit or the sub-driving unit according to a state of the motor to rotate the motor and controlling the main driving unit or the sub-driving unit so that the main driving unit or the sub-driving unit which is being driven is turned off and the main driving unit or the sub-driving unit which is in a stop state is driven when the temperature measured by the temperature sensor unit becomes a predetermined temperature or more, and a control method thereof.

Abstract: In a motor driving device, a first relay portion is connected between a power source and an inverter portion, a second relay portion is connected between the first relay portion and the inverter portion, and a motor relay portion is connected between the inverter portion and a winding group of a motor. Inverter pre-driver circuits respectively drive switching elements of the inverter portion. A first pre-driver circuit drives the first relay portion. A second pre-driver circuit drives the second relay portion and the motor relay portion. A controller controls driving of the inverter portion, the first relay portion, the second relay portion, and the motor relay portion, and detects a failure of the first relay portion, the second relay portion, and the motor relay portion.

Abstract: A method and apparatus for controlling a motor. The motor comprises windings. A switch bridge comprising a plurality of switches is configured to couple a power source to the windings. A motor controller is configured to control the plurality of switches. An undesired condition identifier is configured to identify an undesired condition when the motor is providing power to the power source, wherein the undesired condition is defined with respect to a characteristic of the power source. An undesired condition reducer is configured to reduce the undesired condition in response to identifying the undesired condition by the undesired condition identifier.

Abstract: A temperature protection device basically includes a temperature detector, a temperature estimator, an overheated determining component and an overheating protection component. The temperature detector detects a temperature of a semiconductor component. The temperature estimator estimates an estimated temperature of the semiconductor component. The overheated determining component determines whether the semiconductor component is in an overheated state based on the detected temperature and the estimated temperature by using a first estimated temperature as the estimated temperature at a time point when the detected temperature has reached a first threshold temperature and a second estimated temperature that is estimated subsequent to the time point as the estimated temperature when the detected temperature has reached the first threshold temperature.

Abstract: The present disclosure discloses a converter system, which at least includes the first and second back-to-back converters. The first back-to-back converter includes a first rectifier module and a first inverter module. The first rectifier module is used to convert a first AC voltage to a first DC voltage. The first inverter module is used to convert the first DC voltage to a second AC voltage. The second back-to-back converter includes a second rectifier module and a second inverter module. The second rectifier module is used to convert the first AC voltage to a second DC voltage. The second inverter module is used to convert the second DC voltage to the second AC voltage. The converter system can suppress the circular current through the synchronous operation of the first and second rectifiers or the synchronous operation of the first and second inverters.

Abstract: A vehicle including an AC rotating electric machine, an inverter, and an electronic control unit is provided. When an overcurrent abnormality occurs, i.e., phase current of a motor-generator exceeds a permissible value, in a high rotational speed region, the electronic control unit performs control (upshift control) for shifting up an automatic transmission provided between the motor-generator and driving wheels, or control (neutral control) for bringing the transmission into a released state, so as to reduce the rotational speed of the motor-generator. If phase current is detected even when an all-gate turn-off command is generated to the inverter while the rotational speed of the motor-generator is reduced to be within a low rotational speed region under the upshift control or neutral control, the electronic control unit determines that a short-circuit fault occurs in the inverter.

Abstract: A steering control apparatus includes a direct current power source, a three-phase alternating current motor, and a motor driving circuit. An emergency switching element is provided on at least two phases of a three-phase power supply line connected to the three-phase alternating current motor within the motor driving circuit, and the emergency switching element is turned off when an abnormality occurs such that the motor driving circuit is disconnected from the three-phase alternating current motor. The emergency switching element is a MOSFET, and the MOSFETs are provided in pairs in each of the two phases of the three-phase power supply line. Further, parasitic diodes of the pairs of MOSFETs are disposed in opposite orientations to each other.

Abstract: In an EC motor, comprising a motor electronics, a signal input or a signal output, and an optocoupler for the galvanically isolated transmission of a useful signal between the motor control unit and the signal input or the signal output, the intention is to reliably determine the degradation of the optocoupler and to improve the service life of the EC motor. This is achieved in that an evaluation unit regularly evaluates a saturation voltage of the optocoupler at the output of the optocoupler in relation to a reference threshold when the optocoupler is wired and generates a warning signal when the saturation voltage exceeds the reference threshold.

Abstract: Current imbalance may be detected in a 3-phase power system by monitoring current output between two points of a phase signal provided along wire pairs from an inverter to a motor. In some embodiments, each wire of a wire pair leading to the motor from the inverter may be provided with a line current sensor. A comparison of current output from each wire in the wire pair may be performed to determine if a current imbalance is present. In some embodiments, a phase current sensor may be coupled to a phase input of the inverter. Failures in the 3-phase system may be detected by measuring the output from each phase current sensor for imbalanced distribution of power output. In some embodiments, the output from the phase current sensors may be compared to an output of a line current sensor along the same phase for current imbalances or harness failures.

Abstract: In a control apparatus for a rotary electric machine receiving power from a DC power supply, a DC-AC converting circuit is provided with serially connected circuits each having high-potential-side and low-potential-side switching elements. When a short-circuit occurs at the switching elements, all the switching elements are turned OFF for failsafe and a path connecting the machine and the battery is opened. In such a case, a switching element belonging to part of the switching elements is turned ON, with potential at all the terminals of the rotary electric machine being the same. A location of the short-circuit occurs is identified, based on changes in current passing through the machine and being detected in response to turning ON the switching element. The changes are at least one of a reduction change in deviation of the current from a zero point and a reduction change in an absolute value of the current.

Abstract: A motor drive device has an inverter circuit, in which at least three sets of a pair of upper and lower arms including a semiconductor switching element on an upper arm and a lower arm is arranged, for supplying voltage to a motor based on ON/OFF operation of each semiconductor switching element by a PWM (Pulse Width Modulation) signal, an inverter drive unit for outputting the PWM signal to each semiconductor switching element of the inverter circuit, a fail safe circuit, arranged between the inverter circuit and the motor, including a semiconductor switching element for shielding the voltage supply from the inverter circuit to the motor for each phase, and a fail safe drive unit for outputting a signal for turning ON/OFF the semiconductor switching element of the fail safe circuit.

Abstract: An electric machine assembly with fail-safe arrangement is described. The assembly comprises a stator including a plurality of windings and a cooperating rotor including at least one permanent magnet; a detector configured to detect DC current in at least one of the windings of the stator; and a bypass circuit configured to be activated upon detection of the DC current by the detector and to prevent at least some of the DC current from flowing into the at least one of the windings of the stator.

Abstract: The time required to reverse current flow in an electric motor is reduced by exploiting inductive current that persists in the motor when power is temporarily removed. Energy associated with this inductive current is used to initiate reverse current flow in the motor.

Abstract: Provided is a motor control device (10) for controlling a motor (5) provided with a plurality of sets of windings, in which, when a current control unit (23) detects a short-circuit failure as a primary failure, the current control unit (23) continues the control, and, further, when the current control unit (23) detects a secondary failure, the current control unit (23) provides control of opening a power supply relay (3). Accordingly, in a case where a failure of a winding of a motor or an inverter occurs, a torque pulsation is restrained and a sufficient output torque is provided, and further, in a case where a secondary failure occurs, excessive heat generation and current consumption are prevented and the cost of the device is reduced.

Abstract: The invention relates to a method of safety cutoff of an electromechanical motor vehicle power steering, in which safety switches (26, 27, 28) are provided for electrical separation of a servomotor from a control system or a vehicle electrical system, wherein the following steps are provided: a) receiving a fault signal in a control system (30); b) sending a switch-off signal via control lines (31, 32, 33) to the safety switches (26, 27, 28); c) checking the electrical voltages present on the safety switches (26, 27, 28); d) deciding whether the switch-off signal on each safety switch (26, 27, 28) has led to switch-off; e) if the switch-off signal on one or more safety switches (26, 27, 28) has not led to switch-off, switching those safety switches (26, 27, 28) back on, which could not be switched off; f) repeating steps b) to e) until all safety switches have been switched off successfully (26, 27, 28).

Abstract: A system and method for arc detecting and extinguishing in motors includes a power input interface to a power source; an output interface to a motorized load to deliver power to the motorized load; a set of sensors configured to detect an arc condition in the motorized load; a set of switches switchable to provide a low-impedance pathway parallel to the arc condition in the motorized load; and a controller, coupled to the power input interface, the output interface, the set of sensors, and the set of switches, the controller being configured to switch the set of switches to disconnect the power source, and activate the low-impedance pathway based on the detection of the arc condition, thereby preventing unintentionally generated energy in the motorized load from sustaining the arc condition.

Abstract: Provided are a current detection apparatus having sensor sections detecting motor currents flowing in the windings for the phases of the winding groups, a control apparatus calculating voltage instructions with respect to each winding group, based on the motor current detected by each sensor section, a voltage application apparatus applying voltage to each winding group, based on the voltage instructions, and a failure detection apparatus detecting whether or not each sensor section has failed. The control apparatus, when the failure detection apparatus has detected failure of some of the sensor sections, in accordance with the detection, calculates a voltage instruction with respect to the winding group corresponding to the failure of the sensor section, based on motor current with respect to another winding group detected by the sensor section that can normally detect current.

Abstract: An actuator comprising at least one multiphase motor having phases facing a rotor secured to an outlet shaft associated with a braking member and provided with a connection to a movable element that is to be moved, the motors and the braking member being connected to at least one motor control unit for controlling the motors by powering their phases. The motor has at least four phases wound in such a manner as to avoid a neutral point, and in that the control unit has one single-phase inverter per phase and is arranged to implement a nominal, three-phase mode of control, and a degraded mode of control that enables the rotor to be driven in rotation by powering two non-collinear phases thereof.

Abstract: A control system for an electric motor comprises processing means arranged to perform a control process which includes monitoring electrical voltages applied to the motor and electrical currents in the motor, and determining from them the rotational position of the motor. The system is further arranged to monitor at least one parameter of the control process thereby to detect a stall condition of the motor.

Abstract: A motor control system comprises a plurality of control apparatuses and a host control apparatus, wherein each of the control apparatuses include a position control unit controlling position based on a position command and commanded speed from the host control apparatus, a speed control unit controlling speed based on a speed command from the position control unit, a current control unit controlling current based on a current command from the speed control unit, and a current amplifier which amplifies motor driving current based on a voltage command from the current control unit, and wherein the current control unit includes a voltage saturation processing unit which determines whether the voltage command has exceeded supply voltage of the current amplifier, and which outputs the result of the determination, and a voltage saturation notifying unit which notifies the host control apparatus of the result of the determination made by the voltage saturation processing unit.

Abstract: The present invention relates to a motor drive device having a drive circuit for driving a power supply relay and a phase relay providing a fail-safe function. The motor drive device includes: an inverter circuit for supplying electric power to an electric motor; a power supply relay provided on a power supply line for supplying electric power from a power supply to the inverter circuit; a phase relay provided on a drive line between the inverter circuit and the electric motor, and constituted by a semiconductor switching element; and a drive circuit connected to the phase relay and the power supply relay. The phase relay and the power supply relay share the same drive circuit, and the phase relay and the power supply relay are driven simultaneously by a drive signal output from the drive circuit.

Abstract: A control system includes a current control unit providing, in accordance with the magnetic pole position of a rotor in which permanent magnets are disposed, a first current command to a first excitation phase of a stator winding and providing a second current command to a second excitation phase, a current error calculator calculating a current error which is a difference between a current flowing through the motor during the first period and the first current command or a difference between a current flowing through the motor during the second period and the second current command, and an abnormality detection and diagnosis unit detecting an abnormality based on the speed, the direction of movement and the amount of movement of the motor and the magnitude of the current error.

Abstract: A method and a device for operating a hybrid vehicle, which ascertain the torque necessary for starting the non-operating internal combustion engine, and this torque is reserved by an additional drive unit. The torque necessary for starting the non-operating internal combustion engine is minimized by appropriately adjusting parameters of the internal combustion engine system.

Abstract: A pulse signal output unit sends three-phase pulse signals according to movement of the movable member. A counter unit adds a first predetermined value or a second predetermined value to a count value or subtracts the first predetermined value or the second predetermined value from the count value, according to a combination of the pulse signals appearing when all the pulse signals are normal and a combination of the pulse signals appearing when one of the pulse signals malfunctions. A position detection unit detects the position of the movable member according to the count value.

Abstract: A motor control system for determining an offset correction value is provided. The motor control system includes a motor, an inverter, an inverter controller, and a dynamic offset compensation control module. The inverter is configured to transmit the phase current to the motor. The inverter controller determines the phase current to the motor. The dynamic offset compensation control module is in communication with the inverter controller and the motor, and is configured to perform a method at a fixed periodic interval to determine the offset correction value.

Abstract: According to one embodiment, a controller of a motor includes a driving signal output module, a position detector, a determiner, and an over current detector. The driving signal output module is configured to generate a driving signal for generating a driving current of a motor, a duty ratio of the driving signal being depending on an over current detection signal. The position detector is configured to generate a position detection signal for determining an operating status of the motor by comparing an induction voltage generated by a rotation of a rotor of the motor by the driving current with a predetermined reference voltage. The determiner is configured to determine whether the motor is in a starting state where a rotating frequency of the rotor is smaller than a predetermined value or in a steady state where the rotating frequency of the rotor is equal to or higher than the predetermined value based on the position detection signal.

Abstract: A brushless electrical machine has at least one phase winding which produces torque to drive a load. The control system for the machine is able to vary the flux and current supplied to a phase so as to vary the torque output as a function of the rotor position. The energisation is reduced at particular angles to produce a dip in the torque profile, thus ensuring that, if the drive stalls, it does so at a predetermined position, for example where the losses in the drive are minimised.

Abstract: A circuit for controlling a load current through a coil is connected to an output port of a transistor H-bridge that includes two low side transistors and two high side transistors. A current sense circuit is coupled to the H-bridge and configured to provide a representation of the load current provided by the output port. A current regulator is configured to generate a modulated signal dependent on the representation of the load current and a current set-point. The modulated signal has a duty-cycle. A gate control logic drives the individual transistors of the H-bridge on and off in accordance with the modulated signal. A direction signal provides the load current to the coil. The direction signal determines the direction of the load current. An over current detection circuit is coupled to each individual transistor and is configured to signal an over-current by providing an active over-current failure signal when a transistor current through the respective transistor exceeds a respective maximum value.

Abstract: Example embodiments disclose a drive system including a machine including a plurality of phases and configured to generate power based on a plurality of phase currents, each respectively associated with the plurality of phases and a direct current (DC) bus, operatively connected to the machine. The DC bus includes a high-side line, a low-side line, and an inverter including a plurality of switching systems, operatively connected between the high-side line and the low-side line, the plurality of switching systems, each configured to output a respective one of the plurality of phase currents. The drive system also includes a controller, operatively connected to the DC bus and the machine, the controller configured to determine if a failure exists in the drive system based on the plurality of phase currents and a DC bus voltage, the DC bus voltage being a voltage across the high-side line and the low-side line.

Abstract: Provided is a motor control device including a main calculation unit (101), which takes a first operation state for controlling a brushless motor (5), and a second operation state for stopping the motor control, and a sub calculation unit (102) for monitoring the main calculation unit (101) by means of a first monitoring unit (106) in the first state, for calculating a motor rotation angle in the second state, thereby enabling continuous calculation of the motor rotation angle even when the motor control is stopped, for carrying out monitoring the sub calculation unit (102) by means of second monitoring unit (201), thereby securing reliability, and for calculating the motor rotation angle in a second calculation cycle in the second operation state, the second calculation cycle being longer than a first calculation cycle in the first operation state, thereby reducing a current consumption.

Abstract: A polyphase electrical machine controlled by at least two parallel inverters, each including a number of branches equal to a number of phases of the machine and controlled by PWM. When detecting an inverter branch is faulty, the faulty branch is isolated and the phase in question is powered by each corresponding other inverter branch. The PWM is modified to make power switches of each other branch conductive in succession, without switching while absolute value of the current of the phase in question is greater than or equal to a threshold of 80% to 120% of (n?1)Imax/n, n is number of inverters and Imax is maximum magnitude of the phase current. It is thus possible to continue generating substantially sinusoidal voltages on each of the phases, while avoiding overdimensioning the power switches to ensure in event of a fault they can deliver currents of amplitude higher than in normal operation.

Abstract: An AC motor drive control device including: an inverter, having a plurality of switching elements subjected to on-off control, for converting a DC voltage to an AC voltage with a desired frequency to drive an AC motor; a motor opening contactor connected between the inverter and the AC motor; a switching operation beforehand detection unit for detecting a switching operation of the motor opening contactor prior to the contact or detach of main contacts and outputting a switching operation beforehand detection signal; and a control unit having an inverter control unit for performing the on-off control for the plurality of switching elements and switching control for the motor opening contactor, and controlling the inverter based on the switching operation beforehand detection signal.

Abstract: The disclosed device comprises a duty calculator for calculating a duty command value (Dty), a duty limiter for limiting the duty command value (Dty) to a value according to a limit value (L), a current flow monitor for determining that there is an overcurrent if a current value (Idet) flowing through a winding exceeds a predetermined threshold value (Ithr), and a limit value generator for generating the limit value (L). The limit value generator updates the limit value (L) at predetermined time intervals and for a value corresponding to a difference between the threshold value (Ithr) and the current value (Idet) at a time in order to decrease the current value (Idet) during a period in which the overcurrent is determined.