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Pump control

Pump control description/claims

This application claims the benefit of U.S. Patent Application No. 60/575,136, titled “Pump Control,” filed on May 28, 2004, the entire content of which is incorporated herein by reference.

The present invention relates to a pump, and more particularly to a control system for the pump.

A submersible pump is typically activated to pump water from a well into a connected water tank such that the water pressure within the tank remains within predetermined levels. However, the submersible pump can overheat in a relatively short amount of time if water is unavailable to be pumped to the tank. Additionally, since the number of pump-on times is directly proportional to pump wear, more pump-on time will wear out the pump at a faster rate.

Accordingly, there is a need for a pump control system that detects water availability. In one form, the invention provides a pump control system that includes a water pump, a pressure transducer, a current phase detector, a voltage phase detector, and a micro-controller (“MCU”). When an AC signal is supplied to the pump, the current transducer and related circuitry will sample the AC signal and send the sampled AC signal to a current phase detector whose output indicates an operating current phase of the pump. The output signal of the current phase detector is then fed into the MCU. Meanwhile, an operating voltage of the pump is fed into a voltage phase detector whose output indicates an operating voltage phase of the pump. The output signal of the voltage phase detector is similarly fed into the MCU.

The system also includes a current transformer from which the pump operating current is sampled. The extracted pump operating current is sent to an amplifier to yield a squared current signal. Similarly, the voltage signal is also fed to a second amplifier to yield a squared voltage signal. Both the squared current signal and the squared voltage signal are subsequently sent to the MCU for processing. The MCU determines an actual phase angle difference between the squared current signal and the squared voltage signal. Since the determination process is performed digitally, variations in the operating voltage signals and current signals have minimum or no effect on the process. In this way, inaccuracy and inconsistency of phase angle detection caused by inaccuracy and inconsistency of transistors and amplifiers of the circuits can be minimized or avoided. Furthermore, discretely processing the phase angle allows the system to adjust or control the phase angle settings when different pumps are used for the system.

Additionally, modified amplitudes of the current and voltage signals are filtered and fed into a comparator circuit. The comparator circuit then compares the filtered signals with some reference values. The comparator outputs are subsequently fed into the MCU. The MCU thus outputs a signal to activate a plurality of solid state relays. A display such as an LED, can also be coupled with the MCU to indicate the water pressure detected by one or more semiconductor pressure transducers.

In one construction, the invention provides a pump control system for controlling a fluid pump powered by an AC signal. The pump control system includes a signal phase detector coupled to the fluid pump to detect the AC signal supplied to the fluid pump and to generate phase signals indicating a phase parameter of the AC signal. The pump control system also includes a micro-controller to receive the phase signal and to generate a rectified output signal based on the phase signals, and a relay to control the power supplied to the fluid pump based on the output signal of the micro-controller.

In another construction, the invention provides a pump control system for controlling a fluid pump powered by an AC signal. The pump control system includes a signal phase detector to detect the AC signal supplied to the fluid pump. The AC signal typically has an AC current component and an AC voltage component. As a result, the signal phase detector then generates a phase signal indicating a phase shift between the AC current component and AC voltage component. The pump control system also includes a micro-controller to receive the phase signal and to generate a rectified square wave signal based on the phase shifts, the AC current component and AC voltage component, and a relay to disconnect and to connect the power supplied to the fluid pump based on the rectified square wave signal of the micro-controller.

Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings.

FIG. 1 is a block diagram of a pump control and protection system incorporating the invention.

FIG. 2 is a circuit diagram of the electrical components of one construction of the pump control and protection system of FIG. 1.

FIG. 3 is a circuit diagram of one construction of a phase detector capable of being used in the pump control and protection system of FIG. 1.

FIG. 4 is a circuit diagram of one construction of a reset circuit capable of being used in the pump control and protection system of FIG. 1.

FIG. 5 is a block diagram of a three-phase pump control and protection system incorporating the invention.

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• Utility Patent

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