A high voltage DC electric power generating system includes a poly-phase permanent magnet generator having at least one control winding and a plurality of power windings. Each of the power windings is a phase of the poly-phase permanent magnet generator. A passive rectifier connects a switch to an input of each of the power windings such that the switch is a neutral node in a closed state and a disconnect in an open state.

A motor control system includes an inverter and a plurality of current sensors each positioned in-line between the inverter and a phase coil of the motor. Each current sensor measures the current provided to each phase coil of the motor and provides a signal indicative of each phase current to a controller. In some embodiments, the currents sensors are provided as one or more current sense integrated circuits. A protection circuit protects the current sense integrated circuit from ground bounce by coupling a diode and an opposite facing Zener diode in series between the power supply pin and the ground pin of the integrated circuit.

A controller is provided to drive an inverter circuit for a PMSM. The inverter circuit is connected to a battery through a DC link capacitor, and is driven in one safe state during a fault condition. The controller monitors at least one parameter with respective threshold value to drive the inverter circuit in one safe state comprising an active Short Circuit (SC) and a Freewheel (FW). While in FW state, the controller switches from the FW state to the SC state if the at least one parameter is above the respective threshold. While in SC state, the controller controls engine speed to bring the PMSM to a predetermined speed when the stator temperature is more than a threshold temperature value. The controller switches from the SC state to the FW state.

An electric motor includes: a stator; a rotor; and a printed circuit board, pcb, mounted to an end of the motor, the motor end windings being provided as connections on the pcb. The motor further includes transient voltage suppression, TVS, components on the pcb.

A driver system operable to supply a drive signal to a motor includes a system input adapted to be coupled to an input voltage and a system output adapted to be coupled to the motor. The driver system includes a high-side transistor which has a first terminal coupled to the system input, a second terminal coupled to the system output, and has a control terminal. The driver system includes a low-side transistor which has a first terminal coupled to the system output, a second terminal coupled to a reference potential terminal, and has a control terminal. The driver system includes a low-side gate control circuit which provides a first level current responsive to a low-side digital control signal transitioning from a low state to a high state and provides a second level current if the output voltage is less than an upper reference voltage.

A controller includes a control unit which stops a transfer mechanism in a case where the value of a deterioration indication parameter has exceeded a preset threshold, and determines whether or not an event in which the value of the deterioration indication parameter has exceeded the preset threshold is attributed to deterioration of the transfer mechanism which has progressed over time based on a change pattern of time series data of the value of the deterioration indication parameter, and causes the transfer mechanism to operate at a reduced operation speed, in a case where the control unit determines that the event in which the value of the deterioration indication parameter has exceeded the preset threshold is attributed to the deterioration of the transfer mechanism which has progressed over time.

Lathe control systems and methods are described including stopping a motor prior to reversing direction as well as methods and systems that implement voltage and/or current protection thresholds.

A hydraulic fracturing system for fracturing a subterranean formation is disclosed. In an embodiment, the system can include a plurality of electric pumps fluidly connected to a well associated with the subterranean formation and powered by at least one electric motor, and configured to pump fluid into a wellbore associated with the well at a high pressure; at least one generator electrically coupled to the plurality of electric pumps so as to generate electricity for use by the plurality of electric pumps; a gas compression system fluidly coupled to the at least one generator so as to provide fuel for use by the at least one generator; and a combustible fuel vaporization system gaseously coupled to the gas compression system so as to provide at least one of vaporized fuel or gasified fuel, or a combination thereof, to the gas compression system.

An apparatus according to the aspect of the embodiments includes a phase determiner configured to determine a rotational phase of a rotor, a speed determiner configured to determine a rotational speed of the rotor, a controller having a first control mode for controlling the motor by supplying constant currents to windings, and a discriminator configured to discriminate whether a rotation of the motor is abnormal based on the rotational speed when the rotational speed corresponding to a command speed is equal to or higher than a predetermined value in a state where the controller is controlling the motor in the first control mode. When a signal output from the discriminator indicates that the rotation of the motor is abnormal, the controller stops the motor. When the signal output from the discriminator indicates that the rotation is not abnormal, the controller continues a drive of the motor.

An inverter apparatus includes: an inverter including three high-voltage side switching elements and three low-voltage side switching elements respectively provided in three phases one by one, and driving a three-phase brushless motor; an opening and closing control unit performing controlling so as to cause an electrical angle of the motor to pass through an angle corresponding to a first combination, to rotate twice by 120° each time to one side in a rotary direction, and to rotate once by 120° to the other side in the rotary direction thereafter, by sequentially closing four combinations each of which is formed with one among the high-voltage side switching elements and one among the low-voltage side switching elements; and a detection unit detecting a conduction state of a circuit including the closed high-voltage side and low-voltage side switching elements, wherein all the high-voltage side and low-voltage side switching elements are closed at least once in the four combinations.