WATER PUMP DRY-RUN DETECTION METHOD AND SYSTEM

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Chinese Patent Application 202411690698.4, filed on Nov. 22, 2024, which is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to the field of water pump anomaly detection, and in particular to a water pump dry-run detection method and system.

BACKGROUND

Existing water dispensers, coffee machines, and the like typically require water pumps to draw water from water storage containers. When the container is empty, the water pump may experience a water pump dry-run phenomenon, which leads to hazards such as damage to a device's heating pipe and reduces device service life. Therefore, it is necessary to detect whether the pump is in a dry-run state. In existing detection methods, additional devices such as a flow meter are used, which not only increases device costs but also fails to provide a timely and accurate detection result.

SUMMARY

To address the above issues, the present invention proposes a water pump dry-run detection method and system.

A specific solution is as follows:

• • A water pump dry-run detection method, including the following steps:
  • adding a voltage-current conversion module to a water pump control circuit to convert an operating current signal of a water pump into a voltage signal;
  • collecting, at a frequency, a voltage signal value output by the voltage-current conversion module within one pulse cycle of the water pump in a dry-run state;
  • extracting, based on a preset time range from the voltage signal values collected during the dry-run state, a voltage signal value corresponding to each sampling time point within the time range, and obtaining a first determined threshold corresponding to the dry-run state based on an integral of all the extracted voltage signal values within the time range;
  • during the operation of the water pump, continuously collecting, at a same frequency, voltage signal values output by the voltage-current conversion module, after voltage signal values within one pulse cycle are collected, extracting a voltage signal value corresponding to each sampling time point within the time range from the voltage signal values within the pulse cycle, and then obtaining determined data at a current time point based on an integral of all the extracted voltage signal values within the time range; and
  • determining, based on a magnitude relationship between the determined data and a first determined threshold, whether the water pump is in the dry-run state.

Further, the pulse cycle is a PWM (Pulse Width Modulation) cycle or PFM (Pulse Frequency Modulation) cycle.

Further, when it is determined whether the water pump is in the dry-run state, determining is performed based on a magnitude relationship between the determined data and a final determined threshold, and the final determined threshold is obtained as follows:

• • collecting, at a same frequency, a voltage signal value output by the voltage-current conversion module within one pulse cycle of the water pump in a normal operation state ; extracting, based on a preset time range from the voltage signal values collected during the normal operation state, a voltage signal value extracting, based on a preset time range from the voltage signal values collected during normal operation and the voltage signal values collected during the dry-run state, a voltage signal value corresponding to each sampling time point within the time range, obtaining a second determined threshold corresponding to the normal operation state and a first determined threshold corresponding to the dry-run state based on an integral of all the extracted voltage signal values within the time range, and determine a final determined threshold based on the first determined threshold and the second determined threshold corresponding to each sampling time point within the time range, and obtaining a second determined threshold corresponding to the normal operation state based on an integral of all the extracted voltage signal values within the time range; and determining the final determined threshold based on the first determined threshold and the second determined threshold.

Further, the final determined threshold is between the first determined threshold and the second determined threshold.

Further, the preset time range Δt is determined in the following manner: a time range with with the largest area difference between two variation curves is determined by comparing the two variation curves of voltage signal values with time in the normal operation state and the dry-run state, and the time range is used as the preset time range Δt.

A water pump dry-run detection system, including a water pump control circuit and a controller. The system collects a voltage signal value output by a voltage-current conversion module through the controller and implements the steps of the above method in the embodiment of the present invention.

Further, in the water pump control circuit, the voltage-current conversion module is connected in series with a pump circuit.

Further, the controller is a microcontroller unit (MCU).

The above technical solution is used in the present invention, improving detection timeliness and accuracy, and reducing overall device costs.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a flowchart of a method according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram of a water pump control circuit according to this embodiment.

FIG. 3 is a schematic diagram of a controller according to this embodiment.

FIG. 4 is a diagram of variation curves of voltage signal values with time within one pulse cycle according to this embodiment.

DESCRIPTION OF EMBODIMENTS

To further illustrate each embodiment, the present invention is provided with accompanying drawings. The drawings are a part of the disclosure of the present invention, and are mainly used to illustrate the embodiments and can be used with reference to related descriptions in the specification to explain operating principles of the embodiments. With reference to the content, those skilled in the art shall understand other possible implementations and advantages of the present invention.

The present invention is further illustrated below in conjunction with accompanying drawings and specific embodiments.

First Embodiment

An embodiment of the present invention provides a water pump dry-run detection method. As shown in FIG. 1, the method includes the following steps.

S1: Add a voltage-current conversion module to a water pump control circuit to convert an operating current signal of a water pump into a voltage signal.

FIG. 2 shows a circuit diagram of the water pump control circuit. Two terminals of J1 are connected to the water pump, PWM_P is a water pump switch control signal, the added voltage-current conversion module is a resistor R57, and a voltage across the resistor R57 is measured via receiving the AD_Pump signal, thereby converting the operating current signal of the water pump into the voltage signal. In this embodiment, both the PWM_P and AD_Pump signals are connected to a controller (Microcontroller Unit) as shown in FIG. 3.

S2: Collect, at a frequency, a voltage signal value output by the voltage-current conversion module within one pulse cycle of the water pump in a normal operation state; and collect, at a same frequency, a voltage signal value output by the voltage-current conversion module within one pulse cycle of the water pump in a dry-run state.

The method in this embodiment is applicable to a DC (direct current) water pump, which operates periodically using PWM. Therefore, the pulse cycle is a PWM cycle. In other embodiments, the pulse cycle may alternatively be another type of cycle, such as a PFM cycle, which is not limited herein.

S3: Extract, based on a preset time range Δt from the voltage signal values collected during the normal operation state and the voltage signal values collected during the dry-run state, a voltage signal value corresponding to each sampling time point within the time range Δt, obtain a second determined threshold corresponding to the normal operation state Q1 and a first determined threshold corresponding to the dry-run state Q2 based on an integral of all the extracted voltage signal values within the time range Δt, and determine a final determined threshold Q3 based on the first determined threshold Q2 and the second determined threshold Q1.

S4: During the operation of the water pump, continuously collect, at a same frequency, voltage signal values output by the voltage-current conversion module, after voltage signal values within one pulse cycle are collected, extract a voltage signal value corresponding to each sampling time point within the time range Δt from the voltage signal values within the pulse cycle, and then obtain determined data Q at a current time point based on an integral of all the extracted voltage signal values within the time range Δt.

S5: Determine, based on a magnitude relationship between the determined data Q and the final determined threshold Q3, whether the water pump is in the dry-run state.

FIG. 4 shows variation curves of voltage signal values in a normal operation state and a dry-run state within one pulse cycle (T0-T40) of collection respectively, where a light color indicates the normal operation state, and a dark color indicates the dry-run state. Because variations of the voltage signal values collected within one pulse cycle in the same state is usually small, and a curve shape is usually stable, it is possible to determine whether the water pump is in the dry-run state or the normal operation state by comparing voltage signal values during pump use with voltage signal values in the normal operation state and the dry-run state.

To improve the accuracy of a determining result, in this application, a voltage signal value at a single time point is not used for determining, but the integral of the voltage signal values within a time range is used.

It should be noted that the time range Δt is a relative time range. To be specific, a start time point of the pulse cycle is used as a start time point, and the relative time is time relative to the start time point. When the time range Δt is selected, in this embodiment, a time range with the largest area (the area means an area value obtained by integrating the time values and the voltage signal values) difference between the voltage variation curves corresponding to the normal operation state and the dry-run state is selected. As shown in FIG. 4, an area difference corresponding to a time range from T5 to T10 and an area difference corresponding to a time range from T14 to T21 are both relatively large. Comparatively, the area difference corresponding to the time range from T14 to T21 is the largest, so T14 to T21 can be directly set as the preset time range Δt.

In this embodiment, calculation formulas for the second determined threshold, the first determined threshold, and the determined data are the same, which are all calculated using the integral formula. The second determined threshold corresponding to the normal operation state is set to Q₁=∫V(t)*dt, the first determined threshold corresponding to the dry-run state is set to Q₂=∫V(t)*dt, a determined threshold Q₃ selected based on the second determined threshold and the first determined threshold is between Q₁ and Q₂ (for example, an intermediate value of Q₁ and Q₂, and the determined data at the current time point is set to Q=∫V(t)*dt. If Q is less than Q₃, the water pump is determined to be in the dry-run state; otherwise, the water pump is in the normal operation state.

The above implementation describes a technical solution for dry-run detection based on the final determined threshold obtained in the normal operation state and the dry-run state. In another implementation, it is also possible to determine whether the water pump is in the dry-run state solely based on the first determined threshold obtained in the dry-run state, namely, based on a magnitude relationship between the determined data and the first determined threshold. If the determined data is less than the first determined threshold, the water pump is determined to be in the dry-run state; otherwise, the water pump is in the normal operation state.

The embodiment of the present invention improves detection timeliness and accuracy, and reduces overall device costs.

Second Embodiment

The present invention further provides a water pump dry-run detection system, including a water pump control circuit and a controller. The system collects a voltage signal value output by a voltage-current conversion module through the controller and implements the steps of the above method in the first embodiment of the present invention.

Although the present invention is specifically demonstrated and introduced with reference to preferred implementation solutions, it should be understood by those skilled in the art that all changes made to the present invention in form and detail within the spirit and scope of the claims of present invention as defined by the attached claims shall fall within the protection scope of the present invention.