A system for the resilience of an electric submersible pumping system to a transient power interruption includes a power backup connected to the variable speed drive of the pumping system. A method for controlling the electric submersible pump during the transient power interruption includes connecting a variable speed drive to a power source, charging one or more rechargeable batteries within the power backup, and connecting the power backup to the variable speed drive. The method continues with the steps of operating the motor with the variable speed drive, detecting a disruption in AC power from the power source to the variable speed drive, and applying power from the power backup to the variable speed drive to operate the motor during the transient interruption in electrical power.

A motor control actuator configured to drive a permanent magnet synchronous motor (PMSM) with sensorless Field Oriented Control (FOC) includes: a sampling circuit configured to measure a counter electro motive force (CEMF) or a back electro motive force (BEMF) of the PMSM, while the PMSM rotates, and generate a measurement signal based on the measured CEMF or the measured BEMF; a motor controller including a current controller configured to generate control signals for driving the PMSM, the current controller configured to receive the measurement signal and perform a catch spin sequence for restarting the PMSM while rotating based on the measurement signal; and a multi-phase inverter configured to supply multiple phase voltages to the PMSM based on the control signals. The motor controller is configured to match an output voltage of the multi-phase inverter to the measured CEMF or the measured BEMF during the catch spin sequence.

Provided is a method for the computer-assisted operation of an electric motor which is exposed to a thermal load as a result of the rotational motion of its rotor during operation. In this method, measured data is received during the operation of the electric motor. One or more temperature values are derived from the measured data. A number of temperature characteristics curves are then forecast with differing restart times for defining a cooling period for reducing the thermal load on the electric motor, wherein the approximated temperature value, which results from the approximated temperature value is used as the specific starting value for a restart in the temperature characteristics curve to be forecast.

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 apply a drive signal to the power switch circuit to control the supply of power to the brushless motor. The controller is 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 within a variable speed range of zero to at least 15,000 rotations-per-minute (RPM), and control the drive signal based on the detected angular position of the rotor to electronically commutate the motor within a torque range of zero to at least 15 newton-meters (N.m.) and a power output of zero to at least 1500 watts.

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. The controller detects an initial sector within which the rotor is located at start-up, apply the drive signal so as to rotate the motor to a parking angle associated with the detected initial sector, and control a commutation sequence to drive the motor beginning at the parking angle.

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 method and apparatus are provided for controlling a sensorless multi-phase permanent magnet (PM) motor by sensing induced motor terminal voltages from the PM motor while the rotor is spinning, generating an input voltage vector signal from the plurality of induced motor terminal voltages, projecting the input voltage vector signal to a transformed voltage vector signal which does not include DC-offset components by using a Clarke transformation without a zero component that is applied to the input voltage vector signal, and estimating an initial rotor position of the rotor from the transformed voltage vector signal, wherein said sensing, projecting, and estimating are performed while a power converter for the sensorless multi-phase PM motor is disabled.

A device for estimating a rotation speed and/or a direction of rotation of an induction machine is presented. The device controls stator voltages (uu, uv, uw) of the induction machine so that a voltage space-vector constituted by the stator voltages has a fixed direction and a current space-vector constituted by stator currents (iu, iv, iw) of the induction machine has a pre-determined length or a predetermined d-component. The rotation speed and/or the direction of rotation is/are estimated based on a waveform of a q-component of the current space-vector, where the d-component of the current space-vector is parallel with the voltage space-vector and the q-component of the current space-vector is perpendicular to the voltage space-vector. The device is usable when the induction machine does not have enough magnetic flux for flux-based determination of the rotation speed and/or the direction of rotation.

A method and apparatus is described in which a series of short-circuiting pulses is applied to a motor. A current in the motor is determined after one or more of the series of short circuit pulses has completed. The duration of the short-circuit pulses is adjusted depending on the determined current. The method and apparatus may be used within an arrangement for catching a spinning motor.

The overload relay units within a motor control group have the timing function for their motor thermal memories under the control of a central controller in communication with the overload relays. Thus expensive timing components and control of timestamps can be removed from individual overload relays. Further reduction of individual overload relay components can be accomplished by removing the nonvolatile memory function from the individual overload relays and allowing the central controller to perform the nonvolatile memory functions for the overload relays. The motor thermal model function for the overload relays can remain in the overload relays or might be moved to the central controller if communication bandwidth permits.