An electric machine includes a rotor, a stator, at least one measurement circuit, and a controller. The rotor includes a plurality of salient poles arranged radially around a rotation axis of the electric machine and spaced apart from the rotation axis of the electric machine. The stator includes a plurality of coils configured to selectively align with the plurality of salient poles of the rotor. The at least one measurement circuit is configured to measure at least one current through at least one of the plurality of coils. The measured current includes a current ripple. The controller configured to compute a position of the rotor based on a characteristic of the current ripple.

An electric motor assembly is configured to determine a motor winding resistance value. Predicted values are determined for a first and second position of motor commutator sections relative to the motor brushes, with at least one of the brushes contacting different numbers of the sections in the first position and the second position. The predicted values are based on a temperature value measured by the temperature sensor and a predetermined dependence of variation of the motor resistance dependent on the temperature value. An electric motor current value is measured by a current sensor when the electric motor is substantially at standstill. A selection is made between different factors for determining the motor resistance value using the electric current value, dependent on which of the predicted values most closely corresponds to the electric current value. The motor resistance is determined using said electric current value according to the selected factor.

A hydraulic fracturing system for fracturing a subterranean formation includes a support structure that includes an electric powered pump, arranged in a first area, the electric powered pump powered by at least one electric motor, also arranged in the first area. The system further includes a variable frequency drive (VFD), arranged in a second area proximate the first area, connected to the at least one electric motor to control the speed of the at least one electric motor. The system includes a transformer, arranged in a third area proximate the second area. The system also includes a slide out platform integrated into the first area, the slide out platform being driven between a retracted position and a deployed position.

A motor control system and method for a brushed direct current (BDC) motor using a compensated and corrected ripple count. Motor control circuitry, for example implemented in digital logic such as a microcontroller, receives a coil current signal and a motor voltage signal. Discontinuities in the coil current signal, are counted to generate a ripple count. An observer function derives an angular frequency model estimate using a computational model for the motor applying motor parameters estimated in an initial estimation interval following startup of the motor. A corrected ripple count is generated based on a comparison of a commutation angle of the motor with an angular position based on the angular frequency model estimate. Compensation for cumulative error over the initial estimation interval is derived from a behavioral motor model applying the estimated motor parameters. A motor drive signal is adjusted based on the compensated corrected ripple count.

A vehicle control apparatus includes an inverter, a torque setting unit that sets a first torque command value of a traveling motor based on an accelerator operation amount, a torque correction unit that corrects the first torque command value to a second torque command value by performing feedback of the result of control of the traveling motor to the first torque command value, an inverter control unit that generates a drive signal of switching elements based on the second torque command value and a carrier signal, and a motor lock determination unit. When the traveling motor is determined to be in the motor lock state by the motor lock determination unit, the torque correction unit sets a feedback gain to be smaller than a threshold gain, and the inverter control unit sets the frequency of the carrier signal to be lower than a threshold frequency.

A hydraulic fracturing system for fracturing a subterranean formation includes a support structure that includes an electric powered pump, arranged in a first area, the electric powered pump powered by at least one electric motor, also arranged in the first area. The system further includes a variable frequency drive (VFD), arranged in a second area proximate the first area, connected to the at least one electric motor to control the speed of the at least one electric motor. The system includes a transformer, arranged in a third area proximate the second area. The system also includes a slide out platform integrated into the first area, the slide out platform being driven between a retracted position and a deployed position.

The system is directed to enhancing the energy efficiency of electrical charging systems. The system is utilized in circuits that include a power source such as a battery feeding electrical current into an energy storage device such as a capacitor to charge the capacitor with electrical power. The system of the invention extracts energy from such circuits that would otherwise be converted into heat and thereby wasted. The system includes an energy storage and release device such as a motor that is connected to the circuit and converts the electrical energy therein that would otherwise be converted into heat into mechanical energy or electrical energy by means of monitoring and controlling electrical current flow through the system to maintain it at low and constant levels.

The system is directed to enhancing the energy efficiency of electrical charging systems. The system is utilized in circuits that include a power source such as a battery feeding electrical current into an energy storage device such as a capacitor to charge the capacitor with electrical power. The system of the invention extracts energy from such circuits that would otherwise be converted into heat and thereby wasted. The system includes an energy storage and release device such as a motor that is connected to the circuit and converts the electrical energy therein that would otherwise be converted into heat into mechanical energy or electrical energy by means of monitoring and controlling electrical current flow through the system to maintain it at low and constant levels.

A computer implemented method for operating a wiper system of a sensor enclosure. The wiper system can be configured to receive a camera operating information from one or more cameras. The one or more cameras can be determined to be in an exposure mode based on the camera operating information. A first speed of one or more wipers can be adjusted such that the one or more wipers are not in field of views of the one or more cameras while the one or more cameras are in the exposure mode.

Inverter circuits are provided for motor winding sets, respectively. Control units are provided for the motor winding sets to generate control signals related to driving of the inverter circuits and control currents flowing through the motor winding sets, respectively, thereby controlling driving of a motor. The control mode includes a manual steering mode for controlling the motor according to a steering operation on a steering wheel by a driver and an automatic steering mode for controlling the motor independently of the steering operation on the steering wheel by the driver. The control units are capable of switching the control modes and differentiate the current control according to the control mode. By making the current control different according to the control mode, it is possible to attain optimal characteristics which correspond to each control mode.