A system includes a generator coupled to an engine and configured to generate electricity from rotational movement of a shaft of the engine, a motor configured to be driven by the generator through one or more power conversion components, the motor configured to drive a load, a sensor configured to measure generator output, and a controller configured to detect engine imbalance based on a frequency content of a signal output from the sensor in response to a contribution to the frequency content from the one or more power conversion components and/or the load of the motor being less than a threshold value.

A system includes a generator coupled to an engine and configured to generate electricity from rotational movement of a shaft of the engine, a motor configured to be driven by the generator through one or more power conversion components, the motor configured to drive a load, a sensor configured to measure generator output, and a controller configured to detect engine imbalance based on a frequency content of a signal output from the sensor in response to a contribution to the frequency content from the one or more power conversion components and/or the load of the motor being less than a threshold value.

Technical solutions are described for controlling operation of an electric machine such as a permanent magnet synchronous motor (PMSM) drive or motor control system to protect against excessive machine current or voltage in a PMSM drive. Systems and methods employ a torque control algorithm for PMSMs that uses the constraints of both machine current and voltage capability in PMSM drives, and online torque command modification according to the maximum allowed torque under these machine current and voltage constraints.

A motor protector and a method for operating the same. The motor protector includes: a power supply unit adapted to receive electric power from power supply lines of a motor to power the motor protector; a measuring unit adapted to measure electric parameters of the motor; and a controller configured to at least perform steps of: receiving from the measuring unit the electric parameters; determining, based on the electric parameters, whether the motor experiences a first failure related to overheating of the motor; enabling, in accordance with determination of the first failure of the motor, the power supply unit to power a closing mechanism of the motor protector after a predetermined time, thereby closing the closing mechanism to power the motor by the power supply lines; determining, based on the electric parameters, whether the motor experiences a second failure different from the first failure; and enabling, in accordance with determination of the second failure of the motor, the power supply unit to stop powering the closing mechanism. Hence, the motor protector can discriminate types of the motor failures and adopt corresponding measures for different failures.

A motor protector and a method for operating the same. The motor protector includes: a power supply unit adapted to receive electric power from power supply lines of a motor to power the motor protector; a measuring unit adapted to measure electric parameters of the motor; and a controller configured to at least perform steps of: receiving from the measuring unit the electric parameters; determining, based on the electric parameters, whether the motor experiences a first failure related to overheating of the motor; enabling, in accordance with determination of the first failure of the motor, the power supply unit to power a closing mechanism of the motor protector after a predetermined time, thereby closing the closing mechanism to power the motor by the power supply lines; determining, based on the electric parameters, whether the motor experiences a second failure different from the first failure; and enabling, in accordance with determination of the second failure of the motor, the power supply unit to stop powering the closing mechanism. Hence, the motor protector can discriminate types of the motor failures and adopt corresponding measures for different failures.

A motor control device includes: a step-down device including a DC-output power conversion device having a first mode for outputting first voltage and a second mode for outputting second voltage lower than the first voltage; a power supply device; and a control device, and controls a motor. When a flying object takes off, the control device controls the power conversion device in the first mode. When the control device judges that flight information which is one or both of information of a motor parameter obtained along with control for the motor and information of an environmental factor relevant to the flight altitude of satisfies a predetermined condition, or when the control device has received an mode signal for which the second mode is selected on the basis of the flight information during control for the motor, the control device controls the power conversion device in the second mode.

A method for controlling a three-level brake chopper and a three-level brake chopper including, a first controllable semiconductor switch connected between a positive direct current pole and a first connection point, a second controllable semiconductor switch connected between the first connection point and a neutral direct current pole, a third controllable semiconductor switch connected between the neutral direct current pole and a second connection point, a fourth controllable semiconductor switch connected between the second connection point and a negative direct current pole, resistance means connected between the first connection point and the second connection point, and control means configured to control the second controllable semiconductor switch and the third controllable semiconductor switch into a conducting state in response to detecting a fault in the resistance means.

A motor drive method is a method of driving a motor by a motor drive apparatus. The motor drive apparatus includes an inverter that regulates supply power to the motor that is a synchronous machine and includes a controller that controls the inverter. The method includes changing, before loss of synchronism, a speed of the motor from a second speed range to a first speed range. A speed range in which the motor is operable at a substantially fixed speed is the first speed range, and a speed range that is lower than the first speed range and includes zero speed is the second speed range.

One form of a motor control device includes: a waveform generation unit and an amplifier that generate a drive voltage of a voice coil motor (VCM); a DC offset detection unit that detects a DC offset of the drive voltage; a stop control unit that stops application of the drive voltage to a motor coil when the detected DC offset exceeds an operation stop threshold; a temperature correction value setting unit that sets a temperature correction value corresponding to the DC offset when the detected DC offset is lower than the operation stop threshold; a thermistor that detects an ambient temperature; and a vibration level control unit that varies the drive voltage and controls an amplitude level based on the detected ambient temperature and the set temperature correction value.

An electric propulsion system includes a rotary electric machine having an output member, a rechargeable energy storage system (“RESS”) connected to the electric machine, a user interface device, and a controller. The RESS includes multiple battery modules and a switching circuit, the latter being configured, in response to electronic switching control signals, to connect the battery modules in a parallel-connected (“P-connected”) configuration or a series-connected (“S-connected”) configuration, as a selected battery configuration. The user interface device receives an operator-requested drive mode signal indicative of a desired drive mode of the electric propulsion system. The controller, which is programmed with mode-specific electrical losses associated with the desired drive mode, establishes the selected battery configuration in response to the drive mode signal, and presents a drive mode recommendation via the user interface device when the losses associated with the desired drive mode exceed a calibrated loss threshold.