Anti-interference circuit for self-priming pump of water purifier

Abstract

The utility model discloses an anti-interference circuit used for a water purifier self-priming pump, comprising an MCU, a self-priming pump control module, a current sampling module and an EMC filtering module, the MCU controls the self-priming pump control module according to current information collected by the current sampling module, the self-priming pump control module is used for controlling the on-off of the self-priming pump circuit, and the EMC filtering module is used for filtering the EMC filtering module. The current sampling module is used for collecting current information of a circuit when the self-priming pump works, and the EMC filtering module is used for filtering EMC waveforms generated when the self-priming pump works. Through cooperative work of multiple modules, the problems of locked-rotor protection lag, serious EMC interference, back electromotive force harm and the like of the self-priming pump are solved, a low-cost and high-reliability integrated solution is achieved, and the self-priming pump locked-rotor protection device is suitable for scenes such as portable water purifiers and industrial pump control systems and has remarkable market application value.

Description

Technical Field

[0001] This utility model relates to an anti-interference circuit for a self-priming pump in a water purifier. Background Technology

[0002] Portable water purifiers contain a self-priming pump, which is used to draw in raw water from rivers or homes. Currently, this self-priming pump has the following problems: 1. Risk of stalling: When the self-priming pump is running, it may stall due to blockage by foreign objects or sudden load changes, causing a sharp increase in current and burning out the equipment; 2. EMC interference: Electromagnetic interference generated when the brushes of the self-priming pump are running is radiated through the wires, affecting the normal operation of surrounding electronic equipment. Utility Model Content

[0003] To address the aforementioned problems, this utility model provides an anti-interference circuit for a self-priming pump in a water purifier. This circuit can detect the current of the self-priming pump, control its switching, and eliminate EMC waveforms generated during pump operation, effectively solving the problems mentioned in the background art.

[0004] The technical solution adopted in this utility model is:

[0005] An anti-interference circuit for a self-priming pump in a water purifier includes an MCU, a self-priming pump control module, a current sampling module, and an EMC filtering module. The MCU controls the self-priming pump control module based on the current information collected by the current sampling module. The self-priming pump control module controls the on / off state of the self-priming pump circuit. The current sampling module collects the current information of the circuit when the self-priming pump is working. The EMC filtering module filters out the EMC waveforms generated when the self-priming pump is working.

[0006] Preferably, the self-priming pump control module is a MOSFET Q1. The gate of the MOSFET Q1 is divided into two paths: one path is connected to the MCU through resistor R11, and the other path is connected to the negative terminal of the power supply through resistor R12. The drain of the MOSFET Q1 is divided into two paths: one path is connected to the negative terminal of the self-priming pump, and the other path is connected to both the positive terminal of the self-priming pump and the positive terminal of the power supply. The EMC filter module is located between the positive and negative terminals of the self-priming pump. The source of the MOSFET Q1 is connected to the current sampling module.

[0007] Preferably, the current sampling module includes resistor R15, resistor R13 and capacitor C7. One end of resistor R15 is connected to the source of MOSFET Q1 and the other end is connected to the negative terminal of the power supply. One end of resistor R13 is connected to the source of MOSFET Q1 and the other end is split into two paths: one path is connected to the negative terminal of the power supply after passing through capacitor C7, and the other path is connected to the MCU.

[0008] Preferably, a reverse electromotive force protection module is also included, which is used to absorb the reverse electromotive force when the transistor is turned off and protect the MOSFET Q1.

[0009] Preferably, the reverse electromotive force protection module is a diode D2 disposed between the positive and negative terminals of the self-priming pump, wherein the positive terminal of the diode D2 is connected to the negative terminal of the self-priming pump, and the negative terminal is connected to the positive terminal of the self-priming pump.

[0010] Preferably, the resistor R15 is an alloy resistor.

[0011] This invention solves problems such as delayed stall protection, severe EMC interference, and back electromotive force hazards in self-priming pumps through multi-module collaborative operation, achieving a low-cost, high-reliability integrated solution. It is suitable for scenarios such as portable water purifiers and industrial pump control systems, and has significant market application value.

[0012] The beneficial effects of this utility model are:

[0013] 1. Stall detection and real-time protection:

[0014] High-precision current sampling: The current sampling module uses an alloy resistor R15 (such as manganese copper alloy) as the sampling resistor. Its low temperature coefficient characteristics ensure the high accuracy and stability of current detection. Through the filter voltage divider network composed of resistor R13 and capacitor C7, the current signal is converted into a voltage signal and transmitted to the MCU, effectively suppressing high-frequency noise interference and improving sampling accuracy.

[0015] Fast closed-loop response: The MCU analyzes the current signal in real time. If the current exceeds the preset threshold (such as the current suddenly rising to 2-3 times the rated value when the rotor is stalled), it immediately cuts off the conduction of MOSFET Q1. The response time is ≤10ms, avoiding motor overheating or equipment burnout caused by stalling.

[0016] Active protection mechanism: Compared with traditional fuses or thermal relays, this solution achieves active protection through digital control, eliminating the need for manual intervention and significantly reducing equipment maintenance costs;

[0017] 2. Highly efficient suppression of EMC interference:

[0018] High-frequency noise absorption: Connect a capacitor C30 (recommended capacitance 0.1μF ceramic capacitor) in parallel between the positive and negative terminals of the self-priming pump. This capacitor has low impedance characteristics to transient high-frequency interference (such as electrical spark noise) generated by the brush movement of the self-priming pump, which can quickly absorb high-frequency energy and suppress the radiation and propagation of common-mode interference.

[0019] 3. Reliable protection against back electromotive force:

[0020] Fast discharge path: Diode D2 (such as fast recovery diode FR107) is connected in parallel to the self-priming pump port. When MOSFET Q1 is turned off, the reverse electromotive force generated by the self-priming pump coil forms a discharge circuit through diode D2, which avoids high voltage spikes from breaking down MOSFET Q1 and improves circuit reliability.

[0021] Extended component lifespan: By suppressing the reverse electromotive force, the voltage stress on the MOSFET and the self-priming pump is reduced, thus extending the service life of the core components;

[0022] 4. System integration and cost optimization:

[0023] Highly integrated functions: Integrates current monitoring, stall protection, EMC suppression and reverse protection functions into a single circuit, reducing the use of independent protection devices (such as EMC filters and overcurrent relays) in traditional solutions, and reducing hardware costs and PCB area occupancy.

[0024] Compatibility and scalability: The circuit design is based on general electronic components (such as MOSFETs, ceramic capacitors, and alloy resistors), which are compatible with self-priming pumps of different power and can be extended to other motor drive scenarios (such as water pumps, fans, etc.).

[0025] 5. Improved user experience and device reliability:

[0026] Reduced failure rate: Real-time stall protection and interference suppression reduce equipment failures caused by abnormal current or electromagnetic interference, extending the overall service life of the machine.

[0027] Optimized quiet operation and stability: The EMC filter module effectively reduces the conduction and radiation of brush noise, minimizing interference with surrounding electronic devices (such as Bluetooth modules and sensors) and improving the user experience. Attached Figure Description

[0028] Figure 1 This is the circuit schematic diagram of this utility model. Detailed Implementation

[0029] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0030] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0031] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0032] like Figure 1 As shown, an anti-interference circuit for a self-priming pump in a water purifier includes an MCU, a self-priming pump control module, a current sampling module, an EMC filtering module, and a reverse electromotive force protection module. The MCU controls the self-priming pump control module based on the current information collected by the current sampling module. The self-priming pump control module controls the on / off state of the self-priming pump circuit. The current sampling module collects the current information of the circuit when the self-priming pump is working. The EMC filtering module filters out the EMC waveforms generated when the self-priming pump is working. The reverse electromotive force protection module absorbs the reverse electromotive force when the pump is turned off, protecting the MOSFET Q1.

[0033] The self-priming pump control module is a MOSFET Q1. The gate of the MOSFET Q1 is divided into two paths: one path is connected to the MCU through resistor R11, and the other path is connected to the negative terminal of the power supply through resistor R12. The drain of the MOSFET Q1 is divided into two paths: one path is connected to the negative terminal of the self-priming pump, and the other path is connected to both the positive terminal of the self-priming pump and the positive terminal of the power supply. The EMC filter module is located between the positive and negative terminals of the self-priming pump. The source of the MOSFET Q1 is connected to the current sampling module.

[0034] The current sampling module includes resistors R15 and R13 and capacitor C7. One end of resistor R15 is connected to the source of MOSFET Q1 and the other end is connected to the negative terminal of the power supply. One end of resistor R13 is connected to the source of MOSFET Q1, and the other end is split into two paths: one path is connected to the negative terminal of the power supply after passing through capacitor C7, and the other path is connected to the MCU.

[0035] The reverse electromotive force protection module is a diode D2 disposed between the positive terminal and the negative terminal of the self-priming pump. The positive terminal of the diode D2 is connected to the negative terminal of the self-priming pump, and the negative terminal is connected to the positive terminal of the self-priming pump.

[0036] The resistor R15 is an alloy resistor.

[0037] The working principle of this utility model:

[0038] Power-on phase:

[0039] When the MCU outputs a high-level control signal, the signal drives the gate of the MOSFET Q1 through resistor R11, turning it on. At this time, the positive terminal of the power supply supplies power to the self-priming pump through the drain-source path of the MOSFET Q1, and the self-priming pump starts to run.

[0040] Current monitoring and feedback:

[0041] The self-priming pump's operating current flows through alloy resistor R15 (such as manganese-copper alloy), generating a voltage drop across its terminals. This voltage drop is filtered out by a low-pass filter network composed of resistor R13 and capacitor C7 before being transmitted to the MCU and converted into a digital current signal.

[0042] Block detection and protection:

[0043] The MCU analyzes the current signal in real time. If the current exceeds a preset threshold (e.g., twice the rated current), the MCU immediately outputs a low-level signal to turn off the MOSFET Q1, cut off the power supply to the self-priming pump, and prevent equipment damage caused by stalling.

[0044] EMC interference suppression:

[0045] The high-frequency interference (such as electrical spark noise) generated by the brush movement of the self-priming pump is absorbed by the capacitor C30 (0.1μF ceramic capacitor) connected in parallel between the positive and negative terminals of the self-priming pump, forming a low-impedance circuit and suppressing the radiation and conduction of common-mode interference.

[0046] Back EMF protection:

[0047] When MOSFET Q1 is turned off, the reverse electromotive force generated by the self-priming pump coil forms a discharge circuit through the parallel diode D2 (fast recovery diode FR107), preventing high voltage spikes from damaging the MOSFET.

[0048] Working principle of the self-priming pump control module (MOSFET Q1):

[0049] On control:

[0050] The gate of MOSFET Q1 is driven by the MCU through resistor R11. Resistor R12 (pull-down resistor) ensures that MOSFET Q1 remains off when the MCU does not output a signal, thus avoiding false triggering.

[0051] Current path:

[0052] When the circuit is turned on, the circuit is as follows: positive terminal of power supply → positive terminal of self-priming pump → negative terminal of self-priming pump → drain of MOSFET Q1 → source of MOSFET Q1 → current sampling module → negative terminal of power supply, forming a complete circuit.

[0053] Working principle of the current sampling module (R15, R13, C7):

[0054] Current-to-voltage conversion:

[0055] The alloy resistor R15 (low temperature coefficient, high precision) converts the self-priming pump current into a voltage signal;

[0056] Signal conditioning:

[0057] Resistor R13 and capacitor C7 form a low-pass filter to filter out high-frequency noise (such as brush spark interference) and ensure that the voltage signal sampled by the MCU is stable and accurate.

[0058] Working principle of EMC filter module (capacitor C30):

[0059] High-frequency noise absorption:

[0060] Capacitor C30 is connected in parallel between the positive and negative terminals of the self-priming pump. It exhibits low impedance characteristics to transient high-frequency interference (frequency range 10MHz-100MHz) generated by the brush, bypassing it to ground and effectively reducing the amplitude of radiated interference.

[0061] Working principle of the reverse electromotive force protection module (diode D2):

[0062] Leakage path:

[0063] When MOSFET Q1 is turned off, the energy stored in the inductance of the self-priming pump coil generates a reverse electromotive force (up to 50V), and diode D2 conducts in the forward direction, forming a current loop (negative terminal of the self-priming pump → positive terminal of diode D2 → negative terminal of diode D2 → positive terminal of the self-priming pump), quickly dissipating energy and preventing high voltage from damaging the MOSFET.

[0064] Component protection:

[0065] The fast recovery characteristics of diode D2 (reverse recovery time ≤50ns) ensure efficient discharge process and reduce voltage stress damage to MOSFET and self-priming pump.

[0066] Finally, it should be noted that the above examples are merely specific embodiments of this utility model. Obviously, this utility model is not limited to the above embodiments and can have many variations. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of this utility model should be considered within the protection scope of this utility model.

Claims

1. An anti-interference circuit for a self-priming pump in a water purifier, characterized in that, It includes an MCU, a self-priming pump control module, a current sampling module, and an EMC filtering module. The MCU controls the self-priming pump control module based on the current information collected by the current sampling module. The self-priming pump control module is used to control the on / off state of the self-priming pump circuit. The current sampling module is used to collect the current information of the circuit when the self-priming pump is working. The EMC filtering module is used to filter out the EMC waveforms generated when the self-priming pump is working.

2. The anti-interference circuit for a self-priming pump in a water purifier according to claim 1, characterized in that, The self-priming pump control module is a MOSFET Q1. The gate of the MOSFET Q1 is divided into two paths: one path is connected to the MCU through resistor R11, and the other path is connected to the negative terminal of the power supply through resistor R12. The drain of the MOSFET Q1 is divided into two paths: one path is connected to the negative terminal of the self-priming pump, and the other path is connected to both the positive terminal of the self-priming pump and the positive terminal of the power supply. The EMC filter module is located between the positive and negative terminals of the self-priming pump. The source of the MOSFET Q1 is connected to the current sampling module.

3. The anti-interference circuit for a self-priming pump in a water purifier according to claim 2, characterized in that, The current sampling module includes resistors R15 and R13 and capacitor C7. One end of resistor R15 is connected to the source of MOSFET Q1 and the other end is connected to the negative terminal of the power supply. One end of resistor R13 is connected to the source of MOSFET Q1, and the other end is split into two paths: one path is connected to the negative terminal of the power supply after passing through capacitor C7, and the other path is connected to the MCU.

4. The anti-interference circuit for a self-priming pump in a water purifier according to claim 3, characterized in that, It also includes a reverse electromotive force protection module, which is used to absorb the reverse electromotive force when the transistor is turned off and protect the MOSFET Q1.

5. The anti-interference circuit for a self-priming pump in a water purifier according to claim 4, characterized in that, The reverse electromotive force protection module is a diode D2 disposed between the positive terminal and the negative terminal of the self-priming pump. The positive terminal of the diode D2 is connected to the negative terminal of the self-priming pump, and the negative terminal is connected to the positive terminal of the self-priming pump.

6. The anti-interference circuit for a self-priming pump in a water purifier according to claim 5, characterized in that, The resistor R15 is an alloy resistor.

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