The present invention provides an acceleration method for V/f controlled induction motor in flux-weakening region, which comprises: acquiring no-load magnetizing current I.sub.m of the induction motor at current stator frequency; selecting a smaller one of 0.5.Math.I.sub.m(1/σ+1) and (I.sub.m.sup.2+σ)/(I.sub.m+σI.sub.m) as magnetizing current set point, in which σ is an estimated total leakage inductance coefficient; getting an error signal by subtracting the magnetizing current of the induction motor from the magnetizing current set point; determining the stator frequency for the next control period according to the error signal which is provided as a controlling variable of negative feedback. The acceleration method of the present invention can provide the maximum output torque in flux-weakening region and has a larger tolerance for the error of the estimated leakage inductance.

The present invention provides an acceleration method for V/f controlled induction motor in flux-weakening region, which comprises: acquiring no-load magnetizing current I.sub.m of the induction motor at current stator frequency; selecting a smaller one of 0.5.Math.I.sub.m(1/σ+1) and (I.sub.m.sup.2+σ)/(I.sub.m+σI.sub.m) as magnetizing current set point, in which σ is an estimated total leakage inductance coefficient; getting an error signal by subtracting the magnetizing current of the induction motor from the magnetizing current set point; determining the stator frequency for the next control period according to the error signal which is provided as a controlling variable of negative feedback. The acceleration method of the present invention can provide the maximum output torque in flux-weakening region and has a larger tolerance for the error of the estimated leakage inductance.

A motor monitoring system includes a motor unit, a plurality of sensors, and a motor controller. The motor unit includes a motor housing and a motor arranged within the motor housing. The motor includes a stator with a plurality of stator poles each having a corresponding phase coil. The plurality of sensors are arranged within the motor housing and are configured to: measure a first characteristic related to partial discharges that occur at one or more phase coils, and generate sensor data based on the measured first characteristic. The motor controller is configured to generate a plurality of pulse width modulation (PWM) control signals for controlling phase voltages of the motor, detect the partial discharges at at least one of the phase coils based on the sensor data, and adjust at least one PWM control signal of the plurality of PWM control signals based on the detected partial discharges.

The present disclosure is related to ensuring a period for detecting a phase current from a DC bus current of an inverter. A motor control circuit of the present disclosure includes: a voltage command generator and a PWM signal generator. The voltage command generator detects a phase current from a DC bus current of an inverter driving an AC motor, and generating three-phase voltage commands. The PWM signal generator generates three-phase PWM signals to the inverter according to a comparison result of the three-phase voltage commands and a triangular wave signal with a predetermined frequency and outputs the three-phase PWM signals to the inverter. The PWM signal generator corrects a maximum or minimum voltage command by synchronizing the maximum or minimum voltage command with an intermediate command in a first period of multiple consecutive PWM periods.

A motor starter and a method for starting an electric motor are disclosed. In an embodiment, the motor starter includes a phase gating unit and a control unit. The phase gating unit is configured to be deactivated via the control unit after an activity period of the phase gating unit has elapsed and is configured to be deactivated during operation after the activity period has elapsed.

A motor starter and a method for starting an electric motor are disclosed. In an embodiment, the motor starter includes a phase gating unit and a control unit. The phase gating unit is configured to be deactivated via the control unit after an activity period of the phase gating unit has elapsed and is configured to be deactivated during operation after the activity period has elapsed.

A control apparatus controls an inverter which outputs electric power to an electric motor. The control apparatus determines which one of a one-pulse control and a pulse-width modulation control is employed as a control method of the inverter in accordance with a predetermined condition based on an electric motor drive torque of the electric motor, a rotation number of the electric motor, and a DC voltage of the electric motor.

A method for identifying the magnetic anisotropy of an electric rotary field machine comprising a rotor and a stator is described, the method comprising the steps of setting injection pulses of equal absolute values during an injection interval, detecting a respective current response in form of current difference vectors, and determining the anisotropy from the voltage vectors and current difference vectors. Such a method should allow identifying of magnetic anisotropy in a simple way. To this end, injection pulses in the three-phase domain are used.

A method for identifying the magnetic anisotropy of an electric rotary field machine comprising a rotor and a stator is described, the method comprising the steps of setting injection pulses of equal absolute values during an injection interval, detecting a respective current response in form of current difference vectors, and determining the anisotropy from the voltage vectors and current difference vectors. Such a method should allow identifying of magnetic anisotropy in a simple way. To this end, injection pulses in the three-phase domain are used.

An electrified vehicle includes a traction battery, an inverter coupled to the traction battery and operable to convert direct current (DC) power from the traction battery to three-phase alternating current (AC) power, a three-phase electric machine coupled to the inverter by associated cables, a sensor configured to generate a signal associated with rotational position of a rotor of the three-phase electric machine, a current sensor associated with each cable/phase of the three-phase electric machine, and a controller programmed to generate non-zero phase current at each of a plurality of predetermined regularly spaced rotational positions by either adjusting rotor angle or injecting q-axis current, command the inverter to inject a test current pulse to the electric machine, and generate a diagnostic signal in response to any one of the current sensor signals being less than an associated threshold to detect a cable or current sensor anomaly in a single phase.