Abstract: A robot arm calibration device is provided, which includes a light emitter, a light sensing module, a cooperative motion controller and a processing module. The light emitter is disposed on at least one robot arm to emit a light beam. The light sensing module is disposed on at least another robot arm to receive the light beam and the light beam is converted into a plurality of image data. The cooperative motion controller is configured to drive the light emitter and light sensing module on at least two robot arms to a corrected position and a position to be corrected, respectively. The processing module receives the image data and the motion parameters of the at least two robot arms to calculate an error value between the corrected position and the position to be corrected, and analyzes the image data to output a corrected motion parameter for modifying motion command.

Abstract: There is provided a hybrid vehicle including an electronic control unit configured to turn on a second inverter in three phases when an accelerator operation amount is equal to or greater than a predetermined operation amount during predetermined traveling in which the hybrid vehicle is traveling with the engine operated in a state in which a first inverter and a second inverter are shut down and when a rotation speed of a first motor is equal to or less than a predetermined rotation speed. Accordingly, it is possible to rapidly increase a rotation speed of the first motor to be higher than a predetermined rotation speed.

Abstract: A system includes a computer programmed to specify, while a vehicle is turning, a feedback torque based on a steering torque applied to a steering rack and a difference between a desired angle and an actual angle of vehicle steerable wheels. The computer is further programmed to actuate feedback torque to a vehicle steering wheel.

Abstract: A power tool includes a brushless motor, a rectifier circuit configured to rectify an AC voltage supplied from an AC power supply and output a rectified voltage, an inverter circuit configured to perform switching actions with respect to the rectified voltage to be supplied to the brushless motor, a controller configured to control the switching actions of the inverter circuit, a trigger having an operating part being operable by a user, a switch rendered ON and OFF in accordance with an operation performed in the operating part, wherein when the switch is ON, the inverter circuit is electrically connected to the AC power supply whereas when the switch is OFF, and the inverter circuit is electrically disconnected from the AC power supply, and a power supply circuit connected between the switch and the AC power supply and configured to supply a voltage to the controller.

Abstract: A method of detecting a suction condition during operation of a rotary blood pump with an inlet connected to a ventricle of the heart of a patient, an outlet connected to an artery of the patient, a rotor, and a control circuit configured maintain the rotor at a set rotational speed. The method includes measuring the rotational speed of the rotor at a plurality of times during each of a plurality of speed measurement intervals. A speed range is determined between a minimum measured speed and a maximum measured speed during each of the plurality of speed measurement intervals. At least one additional parameter relating to the operation of the blood pump is derived. A suction detection signal is generated if both at least one determined speed range is above a speed range limit and the at least one additional parameter is indicative of a suction condition.

Abstract: A device and associated system for threading, cutting, and reaming pipe ends. The device and system utilize a brushless DC electric motor. The devices also include on-board electronics and operator interface(s) to provide sophisticated control and information as to the various operations. Methods of operating the devices and several different modes for performing various operations.

Abstract: A monitoring apparatus comprises at least one sensor for measuring a current of the electric motor to generate a time-based signal and at least one electronic processor configured to transform the time-based signal into a frequency-based signal and to analyse the frequency-based signal to identify a signal pattern representing a pump fault condition. By monitoring the frequency-based signal, the monitoring apparatus can identify a pump fault condition.

Abstract: A control system for an electric motor comprises a current controller which produces a set of voltage demands for the motor, a current sensing means arranged to produce a current sensing output indicative of electric current in the motor, and a current signal processing means arranged to process the current sensing output signal to produce a modified current signal in which at least one harmonic component present in the current sensing output signal due to inaccuracies in the current measurement is removed or substantially reduced. The modified current signal is combined with a demanded motor current to provide the input to the current controller.

Abstract: A motor drive device includes a power conversion unit configured to supply a drive current to a motor, a current detector configured to detect a current flowing from the power conversion unit into the motor, an A/D converter configured to convert the current detected by the current detector into digital data and outputs the digital data, a motor control unit configured to control the drive current supplied from the power conversion unit to the motor, using the digital data output from the A/D converter, and a sampling adjustment unit configured to adjust a sampling operation of the A/D converter performed for the current detected by the current detector, in accordance with the response time taken after the current detector detects the current until the A/D converter outputs the digital data of the current.

Abstract: An electric power tool in one aspect of the disclosure comprises an operation unit, a bridge circuit having a plurality of switching elements, and a control unit. The control unit is configured to select from the plurality of switching elements a pair of switching elements forming a current path of a motor. The control unit selectively executes one of non-complementary PWM in which one of the selected switching elements is turned on and the other turned on/off, and complementary PWM in which, in addition to the same control as that of the non-complementary PWM, a switching element connected to the same terminal of the motor as the other of the selected switching elements is turned on/off so that an on/off state of the switching element is reversed to that of the other of the selected switching elements.

Abstract: A system includes a rotary electric machine, wiring, a battery that is connected to the rotary electric machine by the wiring harness, and an upper limit value setting section which sets an output upper limit value that is an upper limit of an output command of the rotary electric machine. A control apparatus which controls the rotary electric machine is provided with a temperature acquisition section which acquires the temperature of at least one of the battery and the wiring, an allowable output value calculation section which calculates an allowable output value that is an upper limit allowed for an output command of the rotary electric machine, based on the temperature that is acquired by the temperature acquisition section, and a transmitting section which transmits the allowable output value calculated by the allowable value calculation section to the upper limit value setting section.

Abstract: The present disclosure relates to a method, a terminal device, and a computer readable storage medium for controlling rotation of a servo. The method includes: acquiring a loading mass and a rotation radius of the servo from a sensor electrically connected with the servo or by an externally input; calculating an angular acceleration threshold of the servo according to an angular acceleration formula, a rated torque, the loading mass, and the rotation radius of the servo; setting an angular acceleration of the servo according to the angular acceleration threshold; and rotating the servo according to the angular acceleration.

Abstract: A unique system may include a power absorber; an electrical machine coupled to the power absorber and operative to supply mechanical power to the power absorber; a drive coupled to the electrical machine and operative to supply electrical power to drive the electrical machine; and a controller communicatively coupled to the drive. The controller may be configured to execute program instructions to selectively vary a control voltage while maintaining a given torque output of the electrical machine, and to determine, based on varying the control voltage, a minimum current required for the electrical machine to maintain the given torque output.

Abstract: A rotary position sensor senses rotation of a first member, having a first torque coupling surface, about an axis relative to a second member by sensing movement of a torque receiving component of the rotary. The isolator may include a mount, a linkage and a torsion spring. The linkage is to be coupled to the torque receiving component of the rotary sensor. The linkage has a second torque coupling surface separable from the first torque coupling surface by a play gap, wherein during rotation of the first member, the first torque coupling surface is to contact the second torque coupling surface to transmit torque to the linkage. The torsion spring is captured between the mount and the linkage independent of the torque receiving component to resiliently bias the second torque coupling surface through the play gap and into engagement with the first torque coupling surface.

Abstract: A power tool and method of detecting impacts of a power tool that includes a motor driving a hammer to impact an anvil. A motor control unit is configured to determine a motor characteristic indicative of a speed of the motor. When the motor characteristic indicates that the speed of the motor is below a speed threshold, the motor control unit employs an acceleration-based technique to detect a first impact based on a change in motor acceleration and generate a first impact indication in response to detecting the first impact. When the motor characteristic indicates that the speed is above the speed threshold, the motor control unit employs a time-based technique to detect a second impact based on an elapsed time and generates a second impact indication in response to detecting the second impact.

Abstract: According to one aspect of the present invention, there is provided an electrically controllable rotary pressure device, comprising: a motor for providing torque to rotary pressure means; a power control unit for supplying power to the motor; a central processing unit for controlling the power control unit; and a rotational speed sensor for measuring a rotational speed of the motor or the rotary pressure means, wherein the central processing unit comprises an abnormality detection unit for receiving the rotational speed from the rotational speed sensor, and wherein the abnormality detection unit transmits a control signal to the central processing unit when abnormality in the rotational speed is detected, so that the central processing unit interrupts the power supply of the power control unit.

Abstract: A motor control unit includes a PWM count calculator, a PWM count setter, and a PWM count changer. The PWM count calculator calculates first PWM counts of phases. Each first PWM count is calculated for a current control period. The PWM count setter sets the first PWM count of each phase as a second PWM count of a corresponding phase. The second PWM count is set for each of PWM periods included in the current control period. The PWM count changer changes the second PWM count of at least one of the phases, without changing the total of the second PWM counts of the at least one phase within the current control period, such that the number of times switching elements corresponding to the at least one phase are switched within the current control period is reduced.

Abstract: The present invention provides a ventilation system for improving air quality of an indoor space. The system includes sensors for measuring PM2.5 particle level P, CO2 level C, and TVOC level T in the indoor space. A control circuit is configured to receive P, C and T values and generate an output signal Vout according to a specific algorithm, which in turn controls speed-variable EC motors that drive ventilating fans. The invention exhibits numerous technical merits such as lower energy consumption, programmable operation, high efficiency, and lower noise, among others.

Abstract: Current supplied to electrical submersible pumps in wells is monitored, and signal processing based on wavelet analysis and phase diagram analysis is performed on the data obtained from monitoring. An incipient malfunction of the electrical submersible pump, such as one due to scale build-up in and around the pump, can be detected at an early stage.

Abstract: A power conversion device may include a first inverter to which a first end of each phase winding is coupled; a second inverter to which a second end of each phase winding is coupled; a plurality of switching elements provided in the first and second inverters; a control circuit structured to perform n-phase conduction control on the first and second inverters; and a detection circuit structured to detect a failure in the switching elements. The control circuit is structured such that, when the detection circuit has detected a failure in any of the plurality of switching elements, the control circuit changes the control of the first and second inverters from the n-phase conduction control to m-phase conduction control using m phases of the n phases different from the phase of a winding coupled to the failed switching element, m being an integer not smaller than two and smaller than n.

Abstract: A motor control device of an electric motor includes: a board with a heat sink; multiple switching elements; a drive circuit IC; a control circuit IC; first and second temperature sensors; a temperature information processing unit; and an abnormality determination unit. An out-of-normal-range state is a state where a temperature deviation exceeds a normal deviation threshold, and it is impossible to determine which one of the first and second temperature sensors is abnormal. When both sensors are normal, the temperature information processing unit uses one of first and second detected temperatures. When one sensor is abnormal and the other is normal, the temperature information processing unit uses one of the first and second detected temperatures of a normal sensor. When both sensors fall in the out-of-normal-range state, the temperature information processing unit uses one of the first and second detected temperatures which meets a predetermined condition.

Abstract: A motor drive apparatus which drives a motor includes inverter modules equal in number to phases of the motor. Each of the inverter modules includes a plurality of switching element pairs. Each of the switching element pairs is defined by two switching elements connected in series. In each of the inverter modules, the plurality of switching element pairs are connected in parallel, and each of resistance values of gate resistors connected to the switching elements is set for the corresponding switching element connected thereto.

Abstract: A rotor flux estimator is provided. The rotor flux estimator includes an estimation module that generates a first rotor flux vector expressed in a phase voltage reference frame and a second rotor flux vector expressed in the phase voltage reference frame, from a stator voltage vector expressed in a phase voltage reference frame, a rotational speed of a rotor, and a stator current vector expressed in the phase voltage reference frame. The estimation module includes at least one processor and the estimation module includes a rotor flux current model and a rotor flux voltage model.

Abstract: An inverter for an electric automobile having the following features: the inverter is configured to be connected at one end to a traction battery of the electric automobile and at the other end to a three-phase motor of the electric automobile; the inverter is configured to charge the traction battery if a star point of the three-phase motor is connected to a charging station; and the inverter comprises low-voltage-side switches for interrupting the charging if an operating limit of the inverter is exceeded. The invention furthermore provides a corresponding electric automobile.

Abstract: A torque monitoring system includes a rotatable measurement interface and a stationary data receiver. The measurement interface is configured to be attached to a rotatable shaft. The measurement interface includes a strain gauge, a processor, and a near field communication (NFC) transceiver coil. The stationary data receiver is stationary with respect to the rotating shaft. The stationary data receiver includes a processor and an NFC transceiver coil. The rotatable measurement interface receives operating power via its NFC transceiver coil that is derived from a radio signal wirelessly transmitted by the NFC transceiver coil in the stationary data receiver. The processor in the rotatable measurement interface is configured to receive strain gauge signals from the strain gauge indicative of torque on the rotatable shaft and wirelessly transmit digital data indicative of the strain gauge signals through the NFC transceiver coils to the processor in the stationary data receiver.

Abstract: [Problem] An object of the present invention is to provide a motor control unit that improves a discontinuous feeling of an assist by flexibly making an adjustment of a current command value of a normal system when a failure occurs in any system of multi-system motor control, and enables smooth handling, and to provide an electric power steering apparatus and a vehicle equipped with the same.

Abstract: Method for detecting load differences between at least one first electrical machine and at least one second electrical machine connected in parallel thereto, which are fed by an inverter, wherein the machines each are connected to the inverter via three supply lines and in two supply lines of the at least one first machine and in one of the supply lines of the at least one second machine, the currents are measured with the aid of current measuring sensors in the respective supply lines and, on the basis of the measured current values of the at least one first machine, the corresponding unmeasured currents of the at least one second machine are estimated, and the estimated total current of the supply lines of the at least one second machine is detected as a measure of deviation of the currents of the at least one second machine from the at least one first machine.

Abstract: An apparatus for lifting and sliding a structure to be attached to a wall of a building, including a lifting platform extending outwardly from the building, and a synchronous lifting and sliding system which is arranged on the lifting platform. The lifting platform has two platform beams extending outwardly from the building, and a lifting beam placed on the platform beams. The synchronous lifting and sliding system has a hydraulic lifter arranged on the lifting beam, a hydraulic jack connected to the lifting beam, and a controller. A connecting rod is connected to one end of the hydraulic jack, and several installing holes are arranged at regular intervals on the connecting rod. The distance between the adjacent installing holes of the connecting rod matches a stroke of the hydraulic jack. An installing ear-plate is provided on the platform beam to connect with the connecting rod.

Abstract: A fault detection method for a multi-phase motor system applies a first duty cycle to first phase coil windings and applies a second duty cycle to second phase coil windings. The second duty cycle differs from the first duty cycle by a first difference value D1. A first current I1 is measured. A third duty cycle is applied to third phase coil windings and a fourth duty cycle is applied to the second phase coil windings. The fourth duty cycle differs from the third duty cycle by a second difference value D2. A second current I2 is measured. Line-to-line resistances R1, R2 are calculated using the difference values D1, D2, the measured currents 11, I2, and a measured DC voltage VDC. After determining a resistance difference ?R between the line-to-line resistances R1, R2, a comparison to a first non-zero threshold T1 indicates a fault.

Abstract: A system and method for controlling a grid-connected reactive power compensation inverter. The system uses a combination of feedforward and feedback controls to compute a reference voltage signal based on sensor-measured voltages and currents, where the reference voltage signal is used to control the inverter switches. The disclosed method modifies a cross-couple feedforward signal used in the reference voltage calculations, where the modified cross-couple signal includes a combination of both reference and actual currents, and the modified control scheme reduces the DC-link voltage overshoot experienced during a capacitive overload event while still providing the required reactive power and maintaining grid system stability.

Abstract: A surgical manipulator operates in a manual mode in which a user applies forces and torques to the surgical instrument to cause movement of the energy applicator. The surgical manipulator also operates in a semi-autonomous mode in which the surgical manipulator moves the energy applicator along a tool path. A controller monitors output of a force/torque sensor as the energy applicator is being moved along the tool path in the semi-autonomous mode and transitions from the semi-autonomous mode to the manual mode in response to the output exceeding a limit.

Abstract: Method for dissipating the elastically stored energy of a tool operated with an electric motor (20), comprising determining the rotational speed of the electric motor; determining a limit torque for the electric motor (20) using the rotational speed, at which limit torque the energy is converted at least predominantly into copper losses of the electric motor; and driving the electric motor (20) by means of a rotational speed regulation with a decreasing rotational speed, while complying with the limit torque as motor torque upper limit.

Abstract: An impact tool includes a controller configured to control power being delivered to the and operable in one of: (a) a normal mode where the controller allows power to be delivered to the motor so that the impact mechanism transitions from operation in the rotary mode to operation in the impacting mode when an output torque exceeds a normal transition torque; and (b) a control mode where the controller controls power being delivered to the motor so that the impact mechanism transitions from operation in the rotary mode to operation in the impacting mode when an output torque exceeds a control transition torque that is greater than the normal transition torque.

Abstract: A drive power control device includes: a modeling error reduction unit configured to calculate a correction torque by performing high-pass filter processing on a correction amount calculated by a correction amount calculation unit; a control motor torque command value calculation unit configured to calculate a control motor torque command value by adding the correction torque to a motor torque command value; and a slip reduction control unit configured to perform, when the vehicle starts traveling or slip is detected, control to reduce slip by switching the cutoff frequency of a high-pass filter HPF to be low as compared with normal traveling.

Abstract: A surgical instrument includes: an end effector; a power source; a motor coupled to the power source, the motor configured to actuate the end effector; and a controller operatively coupled to the motor and configured to control the motor based on a current draw of the motor and an angular velocity of the motor.

Abstract: A method with respect to a system that includes an electrical motor and a speed output unit, and the electrical motor is followed by a gear, wherein the following acts are performed by a processor of a controller of a motor drive: monitoring a first set of frequencies from the system over a measurement period when the system is in a known good operating condition; storing the first set of monitored frequencies or derivatives thereof as reference data in a long-term storage system, monitoring a second set of frequencies from the system over a measurement period when the system is in an unknown operating condition, comparing the second set of monitored frequencies with the first set of monitored frequencies in a frequency domain and in the frequency domain, detecting changes between corresponding frequencies resulting from the second set of monitored frequencies and the first set of monitored frequencies.

Abstract: A motor control apparatus applied to a structure in which a plurality of synchronous motors connected in parallel and mechanically coupled to each other is driven by a single power converter, includes a vector control unit and an abnormality detection unit. The vector control unit divides a current flowing in/out the synchronous motors into a q-axis current and a d-axis current and individually controls the divided currents based on a q-axis current command value and a d-axis current command value. The abnormality detection unit detects whether at least one synchronous motor is wrongly wired or is disconnected based on a q-axis inductance, the q-axis current command value, a rotation speed of the synchronous motors, and a d-axis voltage command value.

Abstract: A method of controlling a motor in a motor control system is provided. The method determines a control voltage budget value based on an operating region of the motor. The method adjusts a supply voltage signal based on the control voltage budget value. The method determines a motor voltage command based on the adjusted supply voltage signal. The method applies a voltage corresponding to the motor voltage command to the motor in order to generate a desired motor torque.

Abstract: Disclosed are object detection systems for automated compartment closure assemblies, methods for operating such systems, and motor vehicles with a power liftgate assembly and foreign object detection capabilities. A method is disclosed for detecting objects obstructing the path of an automated closure assembly. The method includes receiving a command signal to move the closure assembly to an open or closed position, and receiving gesture-sensitive sensor signals with a location and velocity of an object within a supervision field. Responsive to the object being inside a protected zone within the supervision field or the object's velocity being towards the protected zone, commanding an automated driving mechanism to: slow the closure assembly's speed; if the object is still located inside the protected zone after a calibrated period of time, stop the closure assembly; and if the object moves outside the protected zone, increase the closure assembly speed to a default speed.

Abstract: To provide a controller of a rotary electric machine which can prevent the vibration torque component to be outputted by the rotary electric machine from being upper-limited by the maximum output torque of the rotary electric machine. A controller of a rotary electric machine decreases an amplitude of the vibration torque command value so that a vibration maximum value obtained by adding an amplitude of a vibration torque command value to a basic torque command value becomes less than or equal to an upper limit command value; and calculates a value obtained by upper-limiting an addition torque command value, which is obtained by adding the vibration torque command value to the basic torque command value, by the upper limit command value, as a final torque command value.

Abstract: A control circuit controls driving of a motor to switch over a shift range. A target rotation speed setting part sets a target rotation speed of the motor. A rotation speed detection part detects a present rotation speed, which is an actual rotation speed, of the motor. A rotation speed error calculation part calculates a rotation speed error, which is an error between the target rotation speed and the present rotation speed. A request torque calculation part calculates a request torque for the motor based on the rotation speed error. A phase lead correction value calculation part calculates a phase lead correction value of a current supply phase relative to a rotation phase of a rotor of the motor based on the request torque.

Abstract: A method for controlling a ceiling fan motor includes: setting a target value of rotational speed and a limited value of rotational torque; controlling the ceiling fan motor to operate; obtaining operation information of the ceiling fan motor; calculating a current rotational speed and a current rotational torque according to the operation information; determining whether the current rotational torque is greater than or equal to the limited value of rotational torque; performing a constant rotational torque operation when the current rotational torque is greater than or equal to the limited value of rotational torque; determining whether the current rotational speed reaches the target value of rotational speed when the current rotational torque is less than the limited value of rotational torque; performing a constant rotational speed operation when the current rotational speed reaches the target value of rotational speed; and increasing torque current of the ceiling fan motor.

Abstract: A pump assembly (1) includes a pump unit (2) capable of providing a desired head (H0) at zero flow rate, a brushless speed-controlled permanent-magnet AC drive motor (205) for driving the pump unit (2), and a control unit for controlling the drive motor (205). The control unit includes a frequency converter configured to receive an input voltage (Uin). The drive motor (205) is operable in a field-weakening mode and non-field-weakening mode. The drive motor (205) is undersized for driving the pump unit (2) at a design input voltage (U0) to provide a lower head (H) than the desired head (H0) at zero flow rate in the non-field-weakening mode and for driving the pump unit (2) to provide the desired head (H0) at zero flow rate in the field-weakening mode.

Abstract: A system and method for inhibiting automatic movement of a barrier that includes determining a current state of the barrier when a vehicle travels through at least one first zone associated with the barrier. The system and method also include analyzing sensor data to determine if at least one: individual or object is located within a movement path of the barrier. The system and method further include inhibiting a sending of the at least one barrier control signal that is automatically sent to move the barrier once the vehicle travels through at least one second zone upon determining that the at least one: individual or object is located within the movement path of the barrier. Additionally, the system and method include presenting a user interface alert relating to inhibiting the automatic movement of the barrier.

Abstract: The inventive method is of the type of those comprising a control stage for driving mode operation of the machine (12) in which currents of the phases in phase windings (u, v, w) of a stator (10) of the machine, which is connected to an on-board power system (2, 15) supplied by a battery (2) providing a predetermined nominal voltage (Ubat), is “full wave” controlled. In accordance with the invention, the control stage is preceded by a pre-magnetizing stage of the stator in open circuit, in which an electromotive peak force between phases substantially equal to the nominal voltage is created by a rotor excitation current (Ir) of a rotor (8) of the machine.

Abstract: Systems and methods for protecting a generator are provided. An example method can include receiving a signal indicative of a voltage associated with a stator. The method can include receiving a signal indicative of a nominal voltage associated with the stator. The method can include receiving a signal indicative of a monitoring state associated with the generator. The method can include receiving a signal indicative of a deadband range. The method can include determining a voltage ratio based at least in part on the voltage associated with the stator and the nominal voltage. The method can include determining an adjusted operating limit using a multiplier determined based at least in part on the voltage ratio. The method can include generating a power command to control operation of the generator based at least in part on the adjusted operating limit.

Abstract: A drive system shifts an inverter from a gate blocking state to a three phase-on state. When it is determined that electric current flows in a diode of an upper arm of the inverter by referring to a phase current of each phase of a motor, the drive system turns on a switching element of the upper arm and thereby shifts the inverter to an upper arm three phase-on state. When it is determined that electric current flows in a diode of a lower arm of the inverter by referring to the phase current of each phase, the drive system turns on a switching element of the lower arm and thereby shifts the inverter to a lower arm three phase-on state.

Abstract: A charge/discharge system includes a controller to control an electric power converter placed between a capacitor and a secondary battery connected in parallel. The controller includes: a request power calculation unit configured to calculate request input/output power for the electric motor generator based on current and voltage of the capacitor and input output current of the electric power converter; a capacitor discharging bias factor map configured to specify a ratio of electric power to be supplied from the capacitor to the electric motor generator to the request input power of the electric motor generator; a capacitor charging bias factor map configured to specify a ratio of electric power to be stored in the capacitor from the electric motor generator to the request output power of the electric motor generator; and a subtraction unit configured to calculate charge/discharge power of the secondary battery by subtracting, from the request input/output power, the charge/discharge power of the capacitor.

Abstract: A method for compensating for a delay in a feedback branch of a servo drive, wherein the servo drive is provided for power-steering a vehicle, includes determining the delay. The method further includes arithmetically compensating for the delay by measuring the spatial expansions of a corresponding metal conductor of the servo drive and the feedback branch. The delay takes place due to formation of eddy currents.

Abstract: A method for determining the phase currents of an electric machine having a power converter, and a stator, the power converter having, for each phase, an upper branch having an upper switch and a lower branch having a lower switch, all the upper branches being connected to an upper DC voltage terminal and all the lower branches to a lower DC voltage terminal. The power converter is operated in an active rectification mode in which each upper switch is closed only as long as a phase voltage at the relevant upper switch is higher than a voltage at the upper DC voltage terminal, and each lower switch being closed only as long as a phase voltage at the relevant lower switch is lower than a voltage at the lower DC voltage terminal; phase branch currents being measured in all the lower branches.