A signal processor is provided comprising one or more signal processor modules configured to: compare signaling containing information about historical data related to the performance of a pump; and provide corresponding signaling containing information about predicted maintenance needs of the pump on a real time basis based at least partly on the signaling compared containing information about the historical data related to the performance of the pump. The one or more signal processor modules may be configured to compare over time the hydraulic power generated by the pump and electric power consumed by a motor driving the pump, including tracking a ratio of hydraulic to electric power. The one or more signal processor modules may be configured to predict maintenance needs based on an algorithm that takes into account a trade-off between the cost of power consumed by a motor driving the pump and the cost associated with the pump maintenance in order to substantially minimize the total cost of operating the pump.

To improve the accuracy of detecting a current flowing through an electric compressor after operation of the electric compressor, the electric compressor having a large change in temperature before and after operation. An inverter-integrated electric compressor (1) that compresses and discharges a refrigerant suctioned therein, includes an inverter device (2) provided with a circuit board (60) mounted with an inverter circuit (40), the inverter device (2) being integrally incorporated in an inverter case. The circuit board (60) is provided with a current detection circuit (30) that detects an input current flowing through the inverter circuit (40), and an offset correction circuit (20). The current detection circuit (30) includes a shunt resistor (32) that is serially connected to the inverter circuit (40) and detects a current, and a first amplifier (31) that amplifies and outputs a voltage appearing as a voltage drop in the shunt resistor (32). The offset correction circuit (20) includes a second amplifier (21) that performs an offset correction of the first amplifier (31). The first amplifier (31) and the second amplifier (21) are integrated into a single integrated circuit.

A control system and method of a VFD-based pump. The control system controls an electric motor via a VFD, and the electric motor drives the pump. The control system comprises: an anti-ripple injection module for injecting an anti-ripple signal into a control path, the anti-ripple signal causing pressure ripples in the pump output to be at least partially cancelled. Further a pump system, comprising: a VFD, an electric motor, and a pump, wherein the VFD comprises the control system stated above.

A method controls the start-up of an oil pump of a gearbox by a brushless electric motor that has no position sensor. The stator coils are powered from the off mode in a constant-current open-loop control sequence until the pump reaches a speed threshold at which speed regulation switches over to closed-loop control on a setpoint corresponding to the lubrication flow rate required to ensure the reliability of the gearbox, but without in so doing exceeding a current threshold indicative of pump seizure, at which point motor control switches back over to the constant-current open-loop control sequence. The open-loop current setpoint is higher than the threshold for switching over to closed-loop control so that in the open-loop control mode the motor torque available at the pump is higher than in the closed-loop control mode.

A compressor driving apparatus, or a home appliance including the same, includes a DC terminal capacitor to store a charge, an inverter to convert direct current associated with the charge of the DC terminal capacitor into an alternating current and output the alternating current to a motor, an output current detection unit to detect an output current flowing in the motor, and an inverter controller to increase a motor speed by starting the motor, and controlling a speed increase of the motor to change based on an increasing slope of a change in an output current detected by the output current detection unit during the speed increase of the motor.

Disclosed are an overload protection apparatus and method, and a storage medium, a compressor and an electric appliance. The apparatus includes: a first overload protection mechanism and a second overload protection mechanism, wherein the first overload protection mechanism is arranged to perform overload protection on the pressure of a compressor to be protected, and/or the second overload protection mechanism is arranged to perform overload protection on at least one of the temperature and the current of the compressor to be protected.

A delivery device for delivering a medium in a vehicle and for limiting a system pressure of the delivery device includes a vehicle pump, which is driven by an electric motor. The electric motor is controlled by a controller, the controller being configured to detect an actual rotational speed of the electric motor and an actual operating current of the electric motor. If the actual operating current of the electric motor exceeds a predefined operating current limit value, the controller is configured to generate a first signal relating to a system pressure being exceeded. The predefined operating current limit value is dependent on the actual rotational speed of the electric motor.

Disclosed are a digitized automatic control method for oil-pumping and a digitized balance-shifting pumpjack, said pumpjack comprising a main motor (15), a decelerator (8), a crank (9), a connecting rod (6), a walking walking beam (3), a balance arm (7), a derrick (5), a horsehead (2), a substructure (12), brake device (13), a beam hanger (1), a load sensor (17), a stroke process measurer, a safety stop device, and a digitized control box (14). A movable counterweight box (28) moves leftward and rightward on the balance arm (7), automatically balancing load at the suspension center in various operating conditions, and pumpjack's frequency of stroke is automatically adjusted according to variations in pump fullness. Features include safety and reliability, convenience of operation, enhanced oil well production, balance rates, energy conservation and consumption reduction.

An anti-ripple injection method for injecting an anti-ripple signal into a control system of a pump is disclosed. The control system controls an electric motor via an electric motor drive, and the electric motor drives the pump. The anti-ripple signal causes pressure ripples in the pump output to be at least partially cancelled. The anti-ripple injection method includes: injecting an anti-ripple signal of any waveform into the control system, the anti-ripple signal being represented by the following equation: f()=.sub.mA.sub.m cos(m+.sub.m), wherein is the rotation angle of the motor shaft, m is the order of a signal harmonic in the anti-ripple signal, A.sub.m and .sub.m are parameters with respect to the m.sup.th signal harmonic. A control system of a pump including the anti-ripple injection apparatus, and a pump system including the control system are also disclosed.

A driving circuit of fluid pump module includes a microprocessor, a primary boost circuit, and a pump driving circuit is provided. The microprocessor receives an output signal with a large-width variable rectangular waveform, a driving voltage, a first detection current-feedback signal, and a second detection current-feedback signal. The primary boost circuit converts an inputted driving voltage into a direct current with a certain high voltage. The pump driving circuit receives the certain high voltage and is connected with the microprocessor to receive the voltage control signal and the pulse-width modulation (PWM) signal. The secondary boost circuit receives the certain high voltage to boost the certain high voltage into a working voltage for the fluid pump. The operation driving circuit receives the working voltage and provides the pulse-width modulation signal for the fluid pump through the second detection current-feedback signal.