Abstract: A system comprising a synchronous three-phase electric motor and a controller is provided. The synchronous three-phase electric motor comprises a rotor, a stator, a plurality of coils, and a plurality of switching devices. The plurality of coils formed from conductive windings each wound around one or more of a plurality of stator teeth of the stator. The plurality of coils comprises a plurality of permanent coils and a plurality of bypass coils. The plurality of switching devices configured to selectively switch between a tapped position and a primary position. The controller is configured to provide a first switching command to the plurality of switching devices to switch from the primary position to the tapped position based on a transition signal. The transition signal is based on comparing an electrical characteristic associated with one or more input currents to the plurality of switching devices with a threshold value.

Abstract: A system comprising a synchronous three-phase electric motor and a controller is provided. The synchronous three-phase electric motor comprises a rotor, a stator, a plurality of coils, and a plurality of switching devices. The plurality of coils formed from conductive windings each wound around one or more of a plurality of stator teeth of the stator. The plurality of coils comprises a plurality of permanent coils and a plurality of bypass coils. The plurality of switching devices configured to selectively switch between a tapped position and a primary position. The controller is configured to provide a first switching command to the plurality of switching devices to switch from the primary position to the tapped position based on a transition signal. The transition signal is based on comparing an electrical characteristic associated with one or more input currents to the plurality of switching devices with a threshold value.

Abstract: Power conversion systems and methods are provided for driving a plurality of motor loads, in which an autotransformer receives AC input currents and provides a plurality of multiphase outputs at a non-zero phase angle relative to one another, and the individual multiphase outputs are provided to corresponding motor drives with rectifiers to convert the multiphase outputs to DC electrical power, and inverters to convert the DC power to AC to drive corresponding motor loads.

Abstract: Power conversion systems and methods are provided for driving a plurality of motor loads, in which an autotransformer receives AC input currents and provides a plurality of multiphase outputs at a non-zero phase angle relative to one another, and the individual multiphase outputs are provided to corresponding motor drives with rectifiers to convert the multiphase outputs to DC electrical power, and inverters to convert the DC power to AC to drive corresponding motor loads.

Abstract: A system and method for precharging a harmonic filter connected to a power supply line to receive AC power and deliver the AC power to the motor drive unit includes a control circuit. The control circuit is configured to monitor an operational state of the motor drive unit or the power supply line, and generate a first control signal upon a predetermined change in the operational state and a second control signal delayed from the first control signal. The system also includes a charging circuit having a first switch configured to actuate in response to the first control signal to provide a reduced power to at least a portion of the harmonic filter and a second switch configured to actuate in response to the second control signal to provide a non-reduced power to the at least a portion of the harmonic filter.

Abstract: A system and method for precharging a harmonic filter connected to a power supply line to receive AC power and deliver the AC power to the motor drive unit includes a control circuit. The control circuit is configured to monitor an operational state of the motor drive unit or the power supply line, and generate a first control signal upon a predetermined change in the operational state and a second control signal delayed from the first control signal. The system also includes a charging circuit having a first switch configured to actuate in response to the first control signal to provide a reduced power to at least a portion of the harmonic filter and a second switch configured to actuate in response to the second control signal to provide a non-reduced power to the at least a portion of the harmonic filter.

Abstract: The d-c bus current, fed to an inverter through a low pass filter, having a shunt-connected capacitor, from the output of an a-c energized a-c to d-c converter (such as a phase-controlled SCR rectifier bridge), is monitored by using a-c current transformers to sense the filter capacitor current and the a-c current supplied to the converter. The transformer output signals are employed to produce a d-c signal which is a reduced amplitude replica of, and has the identical waveshape as, the d-c bus current. The monitoring system is electrically isolated from the power circuitry by means of the a-c current transformers.