Water pump empty pumping detection method and system

Abstract

The invention relates to a water pump empty pumping detection method and system, and the method comprises the steps: adding a voltage and current conversion module in a water pump control circuit, and converting a working current signal of a water pump into a voltage signal; collecting a voltage signal value output by a voltage-current conversion module in a pulse period of the water pump in the empty pumping state at a frequency, and further obtaining a first judgment threshold value corresponding to the empty pumping state; in the use process of the water pump, calculating judgment data at the current moment based on the voltage signal value of the water pump in the pulse period; and whether the water pump is in an empty pumping state or not is judged based on the size relation between the judgment data and a first judgment threshold value. According to the invention, the detection timeliness and accuracy are improved, and the cost of the whole machine is reduced.

Description

Technical Field

[0001] This invention relates to the field of water pump anomaly detection, and in particular to a method and system for detecting water pump dry running. Background Technology

[0002] Existing water dispensers, coffee machines, and similar appliances typically require a water pump to draw water from a container. When the container is empty, the pump will run dry, which can lead to hazards such as damage to the heating element and shorten the lifespan of the equipment. Therefore, it is necessary to detect whether the pump is running dry. Current detection methods usually employ additional equipment such as flow meters, which not only increases equipment costs but also results in untimely and inaccurate information. Summary of the Invention

[0003] To address the aforementioned problems, this invention proposes a method and system for detecting water pump evacuation.

[0004] The specific plan is as follows:

[0005] A method for detecting dry pumping of a water pump includes the following steps:

[0006] Add a voltage-to-current conversion module to the water pump control circuit to convert the water pump's operating current signal into a voltage signal;

[0007] The voltage signal value output by the voltage-to-current conversion module is acquired at a frequency during one pulse cycle when the water pump is in dry running state.

[0008] Based on a set time range, the voltage signal values ​​corresponding to each sampling time within the time range of the collected voltage signal values ​​under the evacuation state are extracted, and the first judgment threshold corresponding to the evacuation state is obtained based on the integral of the extracted voltage signal values ​​within the time range.

[0009] During the operation of the water pump, the voltage signal value output by the voltage-current conversion module is continuously collected at this frequency. After the voltage signal value within a pulse cycle is collected, the voltage signal value corresponding to each sampling time within the time range is extracted from the voltage signal value within the pulse cycle. Then, based on the integral of the extracted voltage signal value within the time range, the judgment data at the current moment is obtained.

[0010] Based on the relationship between the judgment data and the first judgment threshold, it is determined whether the water pump is in a dry pumping state.

[0011] Furthermore, the pulse period is a PWM (Pulse Width Modulation) period or a PFM (Pulse Frequency Modulation) period.

[0012] Furthermore, when determining whether the water pump is in a dry-running state, the judgment is based on the relationship between the judgment data and the final judgment threshold. The final judgment threshold is obtained through the following method:

[0013] The voltage signal value output by the voltage-current conversion module is collected at this frequency within one pulse cycle under normal operating conditions of the water pump; based on a set time range, the voltage signal value corresponding to each sampling time within the time range is extracted from the collected voltage signal value under normal operating conditions, and the second judgment threshold corresponding to normal operating conditions is obtained based on the integral of the extracted voltage signal value within the time range; the final judgment threshold is determined based on the first judgment threshold and the second judgment threshold.

[0014] Furthermore, the final judgment threshold is between the first judgment threshold and the second judgment threshold.

[0015] Furthermore, in selecting the time range, the voltage signal value changes over time under two states: normal operation and no-load operation, and the time range with the largest area difference between the two curves is selected.

[0016] A water pump dry-run detection system includes a water pump control circuit and a controller. The system acquires the voltage signal value output by the voltage-current conversion module through the controller and implements the steps of the method described in the embodiments of the present invention.

[0017] Furthermore, in the water pump control circuit, the voltage-to-current conversion module is connected in series with the water pump circuit.

[0018] Furthermore, the controller is a microcontroller.

[0019] The present invention adopts the above technical solution, which improves the timeliness and accuracy of detection, and reduces the overall cost of the machine. Attached Figure Description

[0020] Figure 1 The diagram shown is a flowchart of a method according to an embodiment of the present invention.

[0021] Figure 2 The diagram shown is a circuit diagram of the water pump control circuit in this embodiment.

[0022] Figure 3 The diagram shown is a schematic of the controller in this embodiment.

[0023] Figure 4 The figure shown is a curve of the voltage signal value changing with time within one pulse cycle in this embodiment. Detailed Implementation

[0024] To further illustrate the various embodiments, the present invention provides accompanying drawings. These drawings are part of the disclosure of the present invention, primarily used to illustrate the embodiments, and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these drawings, those skilled in the art should be able to understand other possible implementations and the advantages of the present invention.

[0025] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0026] Example 1:

[0027] This invention provides a method for detecting dry pumping of a water pump, such as... Figure 1 As shown, the method includes the following steps:

[0028] S1: Add a voltage-to-current conversion module to the water pump control circuit to convert the water pump's operating current signal into a voltage signal.

[0029] like Figure 2 The diagram shows the circuit diagram of the water pump control circuit. The two ports of J1 are connected to the water pump. PWM_P is the water pump switching control signal. The added voltage-to-current conversion module is resistor R57. The voltage across resistor R57 is tested using the AD_Pump signal, thus converting the water pump's operating current signal into a voltage signal. In this embodiment, both PWM_P and AD_Pump signals are as follows... Figure 3 The controller (microcontroller) connection is shown.

[0030] S2: Acquire the voltage signal value output by the voltage-current conversion module within one pulse cycle of the water pump under normal operating conditions at a certain frequency; simultaneously acquire the voltage signal value output by the voltage-current conversion module within one pulse cycle of the water pump under dry conditions at the same frequency.

[0031] The method in this embodiment is applicable to DC water pumps, which operate periodically in a PWM manner. Therefore, the pulse period is the PWM period. In other embodiments, the pulse period may also be other forms of period, such as the PFM period, which is not limited here.

[0032] S3: Based on the set time range, extract the voltage signal values ​​corresponding to each sampling time within the time range from the voltage signal values ​​collected under normal operation and the voltage signal values ​​collected under the no-load state. Based on the integral of the extracted voltage signal values ​​within the time range, obtain the second judgment threshold corresponding to the normal operation state and the first judgment threshold corresponding to the no-load state. Determine the final judgment threshold based on the first judgment threshold and the second judgment threshold.

[0033] S4: During the operation of the water pump, the voltage signal value output by the voltage-current conversion module is continuously collected at this frequency. After the voltage signal value of one pulse cycle is collected, the voltage signal value corresponding to each sampling time within the time range is extracted from the voltage signal value of the pulse cycle. Then, the judgment data at the current moment is obtained based on the integral of the extracted voltage signal value within the time range.

[0034] S5: Based on the relationship between the judgment data and the final judgment threshold, determine whether the water pump is in a dry pumping state.

[0035] like Figure 4 The figure shows the voltage signal value variation curves under two states: normal operation and no-load operation, within one pulse cycle (T0-T40). Lighter colors represent normal operation, and darker colors represent no-load operation. Since the voltage signal value variation within one pulse cycle under the same conditions is usually small, and the curve shape is generally stable, the voltage signal value during pump operation can be compared with the voltage signal values ​​under normal operation and no-load operation to determine whether the pump is in a no-load or normal operation state.

[0036] To make the judgment more accurate, this application does not use the voltage signal value at a single time point for judgment, but uses the integral of the voltage signal value over a period of time for judgment.

[0037] It should be noted that this time range is a relative time, meaning the start time of the pulse cycle is taken as the starting time, and the relative time is the time relative to this starting time. In selecting this time range, this embodiment compares the voltage change curves corresponding to the normal operating state and the no-load state, and selects the time range with the largest area difference between the two curves (area refers to the area after integrating the time value and the voltage signal value). Figure 4 The area differences corresponding to the time ranges T5 to T10 and T14 to T21 are both relatively large. In comparison, the area difference corresponding to the time range T14 to T21 is the largest. Therefore, T14 to T21 can be directly used as the set time range.

[0038] In this embodiment, the calculation formulas for the second judgment threshold, the first judgment threshold, and the judgment data are the same, all using integral formulas. The second judgment threshold corresponding to the normal operating state is set as Q1=∫V(t)*dt, and the first judgment threshold corresponding to the no-load state is set as Q2=∫V(t)*dt. The judgment threshold Q3 selected based on the second and first judgment thresholds is between Q1 and Q2 (e.g., the midpoint between Q1 and Q2). The judgment data at the current moment is Q=∫V(t)*dt. Therefore, when Q is less than Q3, the pump is determined to be in a no-load state; otherwise, it is in a normal operating state.

[0039] The above implementation describes a technical solution for detecting dry pumping by using a final judgment threshold obtained based on normal operating conditions and dry pumping conditions. In another implementation, the judgment can also be made solely by using a first judgment threshold obtained under dry pumping conditions. That is, the pump is judged to be in a dry pumping state based on the relationship between the judgment data and the first judgment threshold. If the judgment data is less than the first judgment threshold, it is determined to be in a dry pumping state; otherwise, it is in a normal operating state.

[0040] The embodiments of the present invention improve the timeliness and accuracy of detection, and reduce the overall cost of the machine.

[0041] Example 2:

[0042] The present invention also provides a water pump dry-run detection system, including a water pump control circuit and a controller. The system acquires the voltage signal value output by the voltage-current conversion module through the controller and implements the steps in the above-described method embodiment of the present invention.

[0043] Although the invention has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that various changes in form and detail may be made to the invention without departing from the spirit and scope of the invention as defined in the appended claims, all of which shall be within the scope of protection of the invention.

Claims

1. A method for detecting dry pumping of a water pump, characterized in that, Includes the following steps: Add a voltage-to-current conversion module to the water pump control circuit to convert the water pump's operating current signal into a voltage signal; The voltage signal value output by the voltage-to-current conversion module is acquired at a frequency during one pulse cycle when the water pump is in dry running state. Based on a set time range, the voltage signal values ​​corresponding to each sampling time within the time range of the collected voltage signal values ​​under the evacuation state are extracted, and the first judgment threshold corresponding to the evacuation state is obtained based on the integral of the extracted voltage signal values ​​within the time range. During the operation of the water pump, the voltage signal value output by the voltage-current conversion module is continuously collected at this frequency. After the voltage signal value within a pulse cycle is collected, the voltage signal value corresponding to each sampling time within the time range is extracted from the voltage signal value within the pulse cycle. Then, based on the integral of the extracted voltage signal value within the time range, the judgment data at the current moment is obtained. Based on the relationship between the judgment data and the first judgment threshold, it is determined whether the water pump is in a dry pumping state.

2. The method for detecting pump dry running according to claim 1, characterized in that: The pulse period is either the PWM period or the PFM period.

3. The method for detecting pump dry running according to claim 1, characterized in that: When determining whether the water pump is in a dry-running state, the judgment is based on the relationship between the judgment data and the final judgment threshold. The final judgment threshold is obtained through the following method: The voltage signal value output by the voltage-current conversion module is collected at this frequency within one pulse cycle under normal operating conditions of the water pump; based on the set time range, the voltage signal value corresponding to each sampling time included in the collected voltage signal value under normal operating conditions is extracted from the voltage signal value under the set time range, and the second judgment threshold corresponding to the normal operating conditions is obtained based on the integral of the extracted voltage signal value under the time range. The final judgment threshold is determined based on the first judgment threshold and the second judgment threshold.

4. The method for detecting pump dry running according to claim 3, characterized in that: The final judgment threshold is between the first judgment threshold and the second judgment threshold.

5. The method for detecting pump dry running according to claim 3, characterized in that: In selecting the time range, the voltage signal value changes over time under two conditions: normal operation and no-load operation. The time range with the largest area difference between the two curves is selected from these two curves.

6. A water pump dry-run detection system, characterized in that: The system includes a water pump control circuit and a controller. The system acquires the voltage signal value output by the voltage-current conversion module through the controller and implements the steps of the method as described in any one of claims 1 to 5.

7. The water pump dry-run detection system according to claim 6, characterized in that: In the water pump control circuit, the voltage-to-current conversion module is connected in series with the water pump circuit.

8. The water pump dry-run detection system according to claim 6, characterized in that: The controller uses a microcontroller.

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