A common mode line-to-ground filter is disclosed which includes but is not limited to a resistor, capacitor and a ground. The common mode line to ground filter is connected on a high side of a step-up transformer. A low side of the step-up transformer is connected to a variable frequency drive that provides a semi-sinusoidal voltage waveform. The common mode line to ground filter generates a filtered sinusoidal waveform from the output of the step-up transformer. The filtered sinusoidal voltage waveform is supplied via an electrical cable to an electrically submersible pump deployed downhole.

A pump control system and an operating method thereof are disclosed. The pump control system includes a pump; a motor mechanically connected to the pump; a motor driving controller electrically coupled to the motor, the motor driving controller configured to control a speed of the motor; a current detection unit electrically coupled between the motor and the motor driving controller or electrically coupled to a power supply input interface of the pump control system; and a main controller electrically coupled to the motor driving controller.

The present disclosure provides a variable-frequency compressor with adaptive heating power control and a method for operating the same. According to an embodiment of the present disclosure, the variable-frequency compressor includes: a compression unit, for compressing a medium entering the variable-frequency compressor; a motor, including a stator and a rotor, for driving the compression unit; and a controller, configured to adaptively control a heating power of a winding of the stator according to information of the variable-frequency compressor.

An embodiment of the present invention provides a control device comprising: an electric detection unit which detects an electric physical quantity relating to a head capacitor provided between a DC power supply and an inverter switching element; and a protection control unit which controls the inverter switching element in accordance with a change in the electric physical quantity so that no electric current flows to the head capacitor.

An automatic self-driving pump system features a pump/motor/drive detector and an automatic self-driving and control design/setup module. In operation, the pump/motor/drive detector receives sensed signaling containing information about a pump/drive for operating in a hydronic pump system, e.g., stored in and sensed from a signature chip or barcode installed that can be scanned by a scanner, and provides corresponding database signaling containing information about parameters for providing automatic pump control design, setup and run to control the pump/drive for operating in the hydronic pump system, based upon the sensed signaling received. The automatic self-driving and control design/setup module receives the corresponding database signaling, and provides control signaling containing information for providing the automatic pump control design, setup and run to control the pump/drive for operating in the hydronic pump system, based upon the corresponding database signaling received.

A method for operating a variable capacity drive circuit of a compressor includes operating first and second four-quadrant switches in a first state in which the first four-quadrant switch is closed and the second four-quadrant switch is open such that a voltage seen by the motor is equal to an AC line voltage. The method also includes operating the first and second four-quadrant switches in a second state where the first four-quadrant switch is open and the second four-quadrant switch is closed such that the voltage seen by the motor is to zero. Further, the method includes providing a positive firing angle and a negative firing angle for defining when the first and second four-quadrant switches are operated in each of the first and second states. Moreover, the method also includes transitioning between the first and second states using the firing angles at a switching frequency determined by the AC line voltage frequency.

Described is a control method for dispensing a hot fluid in a fluid dispensing device, which comprises a power supply source; a source of fluid to be heated; a feed unit configured for picking up the fluid to be heated; a boiler or heat exchanger; a dispensing device configured for dispensing the hot fluid and a data control and processing system which actuates the following steps: a measurement of inlet parameters comprising at least an inlet power value and an inlet temperature of the fluid towards the boiler or heat exchanger; a cyclical calculation of a quantity of heat generated which must supply the boiler or heat exchanger and/or a quantity of fluid dispensed; consequent adjustment of the value of heat generated by the boiler or heat exchanger and/or the quantity of fluid dispensed, as a function of the measurements of the inlet parameters and of a wanted or desired value of outlet temperature of the fluid; the above-mentioned measurement, cyclical calculation and adjustment steps are performed simultaneously and in real time during a step of dispensing fluid by the dispensing device.

A system includes a chemical storage tank, a pipeline, a pump, a first electrostatic probe, and a control unit. The pipeline is connected to the chemical storage tank. The pump is connected to the pipeline and configured to pump a chemical solution from the chemical storage tank into the pipeline. The first electrostatic probe is coupled to the pump and configured to measure an electrostatic voltage of the pump. The control unit is coupled to the first electrostatic probe and configured to obtain a measurement of an electrostatic voltage from the first electrostatic probe.

In some implementations, a controller may obtain a setting for a target discharge pressure associated with a fluid pump driven by a motor that is controlled by a variable frequency drive (VFD). The target discharge pressure may be for use in a pressure test of a system that includes the fluid pump. The controller may determine a target torque for the motor that achieves the target discharge pressure. The controller may cause, via the VFD and in connection with the pressure test, adjustment to a speed of the motor to achieve the target torque for the motor.

In some implementations, a controller may monitor, during a ramp up period of a fluid pump driven by a motor that is controlled by a variable frequency drive (VFD), an intake pressure of the fluid pump and a discharge pressure of the fluid pump. The controller may detect, based on monitoring the intake pressure and the discharge pressure, whether the intake pressure satisfies an intake pressure threshold or the discharge pressure satisfies a discharge pressure threshold. The controller may cause, via the VFD, reduction of a torque of the motor based on the intake pressure satisfying the intake pressure threshold or the discharge pressure satisfying the discharge pressure threshold.