A direct current electrical machine, which includes a rotor that generates a rotor magnetic field, a first commutation cell that includes a winding component, a first switching device, and a second switching device. The first winding component includes a first portion electrically coupled between a first terminal and a second terminal of the first winding component and a second portion electrically coupled between a third terminal and the second terminal of the first winding component. The first switching device is electrically coupled to the first terminal and is closed when a first voltage induced across the first portion by rotation of the rotor magnetic field is positive; and the second switching device is electrically coupled to the third terminal and is closed when a second voltage induced across the second portion by the rotation of the rotor magnetic field is negative.

A motor drive circuit comprises a motor having a plurality of phases, a switching circuit comprising a plurality of electrical switches, a motor current controller that generates voltage demand signals to be passed to a drive circuit for the switches that in turn generate pulse width modulated switching signals for the switching circuit that cause the switches to selectively connect the phases to a power supply so as to cause current to flow through the phases of the motor, and a motor torque controller that produces a demand signal that is fed to an input of the current controller, the motor current controller responding to an error signal that is at least partially dependent on the value of the demand signal. The torque controller in use updates the demand signal at a first sample rate. The motor drive circuit further comprises a downsampling circuit that in use modifies the demand signal under certain operating conditions so that the demand signal is only updated at a second sample rate that is lower than the first rate.

A motor drive circuit comprises a motor having a plurality of phases, a switching circuit comprising a plurality of electrical switches, a motor current controller that generates voltage demand signals to be passed to a drive circuit for the switches that in turn generate pulse width modulated switching signals for the switching circuit that cause the switches to selectively connect the phases to a power supply so as to cause current to flow through the phases of the motor, and a motor torque controller that produces a demand signal that is fed to an input of the current controller, the motor current controller responding to an error signal that is at least partially dependent on the value of the demand signal. The torque controller in use updates the demand signal at a first sample rate. The motor drive circuit further comprises a downsampling circuit that in use modifies the demand signal under certain operating conditions so that the demand signal is only updated at a second sample rate that is lower than the first rate.

A solar powered pump that maximizes available energy usage under variable insolation conditions is disclosed. It also permits the integration of parameters such as minimum flow control, set point operation, etc., without the use of additional sensors, thereby reducing the overall cost of the system.

Methods and systems include an actuator 40 adapted to provide drive power and hold power to an external device. A motor 34 provides for driving the external device to a determined position when the motor 34 is energized. A switching circuit is configured to energize the motor 34 with a high voltage to drive the external device to the determined position and energize the motor 34 with a low voltage to hold the external device in the determined position.

A motor control device of the present invention supplies a detection current to a motor at predetermined time intervals, detects a voltage between the both ends of a smoothing capacitor when the detection current is supplied, and determines whether a connector is inserted or unplugged based on a change in the voltage between the both ends of the smoothing capacitor. Furthermore, if determining that the connector is unplugged, the motor control device decreases the voltage between the both ends of the smoothing capacitor to or below a defined value by discharging the smoothing capacitor.

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.

A rotary drive system having a voltage source and an electric motor. The motor has a stator with independent phases and a rotor, an inverter designed to connect each phase to the voltage source in order to generate phase currents, and a device for controlling the inverter. The control device includes a unit for determining whether the fundamental frequency of the phase currents is lower than a frequency threshold equal to, at the most, 100 Hz, and a unit for generating a command, configured such that, when the fundamental frequency is determine as being lower than the frequency threshold, the command causes the appearance of a homopolar component in the phase currents.

A DC motor is configured so that, while either one of a pair of power feeding brushes makes contact with two commutator segments, the other makes contact with only one of two commutator segments. The DC motor is further provided with: a plurality of coils; a filter unit; and a calculation unit. The number of turns of a predetermined coil among the plurality of coils is different from the numbers of turns of the other coils. The filter unit allows the passing of the waveform of current generated on the basis of the fact that the numbers of turns are different from each other, and interrupts the waveform of current generated at the switching of the states of the contacts of the power feeding brushes to the commutator segments. The calculation unit calculates a rotational speed from the waveform passed through the filter unit.

A DC motor is configured so that, while either one of a pair of power feeding brushes makes contact with two commutator segments, the other makes contact with only one of two commutator segments. The DC motor is further provided with: a plurality of coils; a filter unit; and a calculation unit. The number of turns of a predetermined coil among the plurality of coils is different from the numbers of turns of the other coils. The filter unit allows the passing of the waveform of current generated on the basis of the fact that the numbers of turns are different from each other, and interrupts the waveform of current generated at the switching of the states of the contacts of the power feeding brushes to the commutator segments. The calculation unit calculates a rotational speed from the waveform passed through the filter unit.