A compact motor control system for selectively controlling power from a power source to a load includes a motor switching assembly having a solid state contactor with a plurality of solid state switches. The motor switching assembly also includes at least one direct current (DC) link coupled to the solid state contactor and redundant first and second inverters coupled to the at least one DC link. The motor switching assembly further includes a first relay coupled between the solid state contactor and an input of the inverter and a second relay coupled between the solid state contactor and an input of the second inverter. In addition, the motor control system includes a control system programmed to control the motor switching assembly to selectively supply power to the load from the power source.

A device according to an embodiment includes an inverter main circuit; a detector configured to detect a current of an output line of the inverter main circuit; a starting time controller comprising a rotational phase angle estimator configured to calculate, based on a current response value detected by the detector, a value corresponding to a rotational phase angle of a motor connected to the inverter main circuit in a stationary reference frame, and a rotational speed estimator configured to calculate a value corresponding to a rotational speed of the motor by using the value corresponding to the rotational phase angle when the inverter main circuit is started; and a regular time controller configured to calculate, with the value corresponding to the rotational speed as an initial value, an estimated rotational phase angle of the motor in a rotating reference frame.

A power tool includes a housing, a brushless motor disposed inside the housing, and a controller. The controller is configured to receive power-off signals and power-on signals. Upon receiving a power-on signal, the controller is further configured to receive a time signal indicative of a time interval from the last power-off signal to the current power-on signal. The controller is further configured to determine whether the time interval is greater than or equal to a first time threshold and less than a second time threshold, and brake the motor before start-up if the time interval is greater than or equal to the first time threshold and less than the second time threshold.

A compressor fault diagnostic apparatus including a current sensing unit to sense a current flowing through a motor of the compressor, a fault diagnostic unit to determine whether or not the motor performs a reverse rotation based on the current flowing through the motor, and a cut-off unit to remove power based on a determination of the fault diagnostic unit.

A method of controlling a brushless permanent-magnet motor having a phase winding and a rotor, includes applying voltages of first and second opposing polarities to the phase winding when the rotor is oscillating about a parking position, measuring a plurality of first times, each first time including a time taken for current flowing through the phase winding in response to an applied voltage of the first polarity to exceed a threshold and measuring a plurality of second times, each second time including a time taken for current flowing through the phase winding in response to an applied voltage of the second polarity to exceed the threshold. The method includes determining which of an average magnitude of the plurality of first times and an average magnitude of the plurality of second times has the smaller average magnitude, and determining an amplitude peak of the plurality of times having the smaller average magnitude. The method includes using the amplitude peak to calculate a time window, setting a timer corresponding to the time window at a subsequent determined amplitude peak, and applying a drive voltage to the phase winding during the time window.

Described herein is an electric motor assembly for an environmental control system. The electric motor assembly includes a fan configured to rotate to circulate air within a controlled environment chamber of the environmental control system, and an electric motor coupled to the fan and configured to rotate the fan. The electric motor includes a motor controller configured to receive a braking control signal from a sensor associated with the controlled environment chamber. The braking control signal indicates an entrance to the controlled environment chamber is about to be opened. The motor controller is also configured to initiate braking the electric motor in response to receiving the braking control signal.

A system and method for identifying and responding to a condition in which an electric motor fails to start. A rotor core includes slots in which magnets are received to produce an electrical reluctance. A motor controller determines a position of the rotor, uses the determined position to convert a torque demand to a demanded D-axis current value, and compares the demanded value to a supplied D-axis current value. If the demanded value differs from the supplied value by at least a pre-established threshold amount, then the motor is restarted. Otherwise, the difference between the torque demand and an actual current is used to drive a voltage applied to the motor. The controller may also implement a sensorless technology, and may restart the motor if the demanded value differs from the supplied value by at least the threshold amount even if the sensorless technology determines that the motor started.

A motor control actuator that drives a permanent magnet synchronous motor (PMSM) with sensorless Field Oriented Control includes a sampling circuit that generates a measurement signal by measuring a back electro motive force (BEMF) of the PMSM, while the PMSM rotates; a PLL that receives the measurement signal and extracts an amplitude and an angle of the BEMF from the measurement signal; and a motor controller that generates a first set of two phase alternating current (AC) voltage components based on an estimated rotor angle, generates a second set of two phase AC voltage components based on the amplitude and the angle, and generates control signals for driving the PMSM based on the first set of two phase AC voltage components. The motor controller performs a catch spin sequence for restarting the PMSM while rotating, the catch spin sequence includes a synchronizing period followed by a closed loop control period.

A power tool is provided including a housing, a brushless motor disposed within the housing, a power switch circuit that supplies power from a power source to the brushless motor, and a controller configured to apply a drive signal to the power switch circuit to control the supply of power to the brushless motor. The controller is configured to receive at least one signal associated with a phase current of the motor, detect an angular position of the rotor based on the phase current of the motor within a variable speed range of zero to at least 15,000 rotations-per-minute (RPM), and control the drive signal based on the detected angular position of the rotor to electronically commutate the motor within a torque range of zero to at least 15 newton-meters (N.m.) and a power output of zero to at least 1500 watts.

When a power failure does not occur, power supply to a first terminal of a wiper motor is performed by a first battery, and power supply to a second terminal of the wiper motor is performed by a second battery. When a power failure occurs in one of the first battery or the second battery, power supply to the wiper motor is performed by the other battery that is not in power failure.