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 method for determining the rotational speed and the angle of rotation of a motor shaft of a mechanically commutated DC motor from the measured progression of time of the ripple in the motor current and in the motor terminal voltage occurring during the commutation. A motor state model of the DC motor, to which the measured motor terminal voltage and the measured motor current, an estimated load torque, an estimated rotational speed and an estimated angle of rotation of the DC motor are supplied to a Kalman filter as input variables. By running the motor state model, the Kalman filter provides an estimated current, an adjusted rotational speed and an adjusted angle of rotation of the DC motor as output variables. From the ripple in the measured motor current and the rotational speed, adjusted by the Kalman filter, a ripple detection unit determines the commutation times and, from the latter, derives an estimated rotational speed and an estimated angle of rotation of the DC motor and provides same to the Kalman filter as the input variables.

A motor control device is a device for controlling a drive of a DC motor which is interlocked with an output shaft portion of an actuator. The motor control device includes: a relative position obtainer detecting current fluctuations when switching a connection between a commutator and a brush in the DC motor or when rotating the DC motor and obtaining relative position information of the output shaft portion; and an absolute position obtainer obtaining absolute position information of the output shaft portion using a potentiometer. The motor control device further includes: an actual position setter setting actual position information of the output shaft portion based on at least one of the absolute position information and the relative position information.

This invention is directed to exergy surface shaping and thermodynamic flow control (ESSTFC) for electro-mechanical-thermal (EMT) systems (i.e., irreversible work processes with heat and mass flows). Extended irreversible thermodynamics are utilized to produce consistent thermal equations-of-motion that directly include the exergy destruction terms. A simplified EMT system that models the EMT dynamics of a ship equipped with a railgun is used to demonstrate the application of ESSTFC for designing high performance, stable nonlinear controllers for EMT systems.

A motor driving device having a lock protection mode includes a rotation speed detecting unit, an operating unit, a driving unit, a floating point selecting unit, a BEMF detecting unit, a control unit, and a lock protection unit. The operating unit enters an operating mode after a motor is stably operated, and generates an operating signal having phases according to a commutation sequence, and the driving unit drives the motor. The BEMF detecting unit detects a BEMF of a first floating phase to generate a detection result. The control unit outputs a commutation signal to cause the driving unit to drive the motor. When the rotation speed detecting unit determines that a rotation speed of the motor exceeds a predetermined rotation speed, the rotation speed detecting unit outputs a switching signal to the lock protection unit to enter the lock protection mode.

A surgical stapler. The surgical stapler includes a drive system, an electric motor, a battery and a control system. The drive system includes a movable drive member. The electric motor is mechanically coupled to the drive system. The battery is electrically couplable to the electric motor. The control system is electrically connected to the electric motor and includes an accelerometer. The control system is configured to control a force applied to the drive system based on an acceleration of the movable drive member.

A surgical stapler. The surgical stapler includes a drive system, an electric motor, a battery and a control system. The drive system includes a movable drive member. The electric motor is mechanically coupled to the drive system. The battery is electrically couplable to the electric motor. The control system is electrically connected to the electric motor and includes an accelerometer. The control system is configured to control a force applied to the drive system based on an acceleration of the movable drive member.

An apparatus can comprise a DC power supply to generate a DC electrical signal, a pulse generator to generate an electrical pulse, and an electrical element. The pulse generator and the DC power supply can be electrically coupled together. The electrical element can receive the DC electrical signal and the electrical pulse. The electrical element can generate a magnetic field in response to receiving the DC electrical signal and cool in response to receiving the electrical pulse.

An apparatus can comprise a DC power supply to generate a DC electrical signal, a pulse generator to generate an electrical pulse, and an electrical element. The pulse generator and the DC power supply can be electrically coupled together. The electrical element can receive the DC electrical signal and the electrical pulse. The electrical element can generate a magnetic field in response to receiving the DC electrical signal and cool in response to receiving the electrical pulse.

A first torque estimator determines a first torque estimation value according to a cross product method, and a second torque estimator determines a second torque estimation value according to an energy method. A torque weight adjuster adjusts, using a weighting coefficient calculated in accordance with a predetermined condition, weightings respectively applied to these two types of torque estimation values, and outputs a torque estimation value.