Disclosed herein is an apparatus for controlling an inverter. The apparatus determines the phase of an command voltage in a restart section taking into account the frequency of an input voltage to an electric motor when an input power is reduced below a rated power, the frequency of the input voltage into the electric motor at the time of restarting, a time period for generating a torque, and the phase of the input voltage to the electric motor at the time of the restarting.

Disclosed herein is an apparatus for controlling an inverter in an inverter system. The apparatus includes: a first determining unit to determine a magnitude, a phase and a frequency of an input voltage to an electric motor in the inverter system; and a second determining unit to determine a restart command voltage for generating an inverter driving voltage larger than a residual voltage in the electric motor using the magnitude of the input voltage determined by the first determining unit, when the inverter system is restarted.

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.

An apparatus for restarting a medium voltage inverter is disclosed, wherein the medium voltage inverter can be restarted by estimating a rotor speed when an input power returns from an instantaneous defective state to a normal state, whereby a time to restart the medium voltage inverter can be reduced by a simple configuration to dispense with the need to wait until the rotor speed reaches zero speed.

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 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 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, and apply a drive signal to the power switch circuit to control a commutation of the motor based on the detected angular position of the rotor. If the supply of power to the motor is turned OFF to cause the motor to slow down and is turned back ON while the rotor speed exceeds a speed threshold, the controller electronically brakes the motor for a time interval to measure the phase current of the motor and detects the angular position of the rotor based on the measured phase current.

A motor control device controls the drive of a motor including a motor winding. The motor control device is provided with an energization control unit and a standstill determination unit. The energization control unit controls the energization of the motor winding in accordance with a detection value of a rotational position sensor that detects a rotational position of the motor. The standstill determination unit determines a standstill of the motor. When a standstill of the motor is detected, the energization control unit controls energization in a change pattern that is an energization pattern different from a preset regular pattern in accordance with the detection value of the rotational position sensor.

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.

The invention relates to a method for determining the position (Θ.sub.R) and the rotational speed (n.sub.R) of a rotor of an electrical machine during an active short circuit and a rotor-state determining device (10) designed to carry out the method. The method comprises the steps of determining the short circuit currents (I.sub.u, I.sub.v, I.sub.w) resulting during the short circuit, determining a total current (I.sub.α, I.sub.β) resulting from the short circuit currents (I.sub.u, I.sub.v, I.sub.w), determining a stator current angle (ψ.sub.I) of the total current (I.sub.α, I.sub.β) with respect to a stator coordinate system (α, β), determining a rotor current angle (φ.sub.I) of the total current (I.sub.α, I.sub.β) with respect to a flux direction (d.sub.R) of the rotor, this step comprising the steps of calculating an amount variable (I) of the total current (I.sub.α, I.sub.β), determining the rotor current angle (φ.sub.I) on the basis of a characteristic dependence between the amount variable (I) and a rotor current angle (φ.sub.I), which dependence is created for the electrical machine, the rotor position (Θ.sub.R) corresponding to a sum of the stator current angle (ψ.sub.I) and the rotor current angle (φ.sub.I), and the rotor rotational speed (n.sub.R) resulting from monitoring of the rotor position (Θ.sub.R).

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.