Voltage control circuit and water pump flow control method based on high-resistance isolation

Abstract

The present invention provides a voltage control circuit based on high-resistance isolation and a water pump flow control method. The voltage control circuit based on high-resistance isolation includes: a high-resistance isolation signal sampling module for isolating and reducing the voltage of an input voltage signal; a signal conditioning module for amplifying and conditioning the isolated and reduced-voltage voltage signal; a sampling module for sampling the conditioned signal; and an MCU for determining a target speed control value based on the sampled value to drive the speed of the water pump. After reducing the voltage through high-resistance isolation, the signal is amplified, and then the voltage is sampled and the water pump speed is calculated, thereby achieving the purpose of controlling the water pump flow. Not only does the high voltage achieved by high-resistance isolation protect the safety of the operator, but it can also effectively isolate and collect analog voltage signals to achieve water pump flow control and reduce costs.

Description

Technical Field

[0001] The present invention relates to the technical field of water pump control, and in particular to a voltage control circuit based on high-resistance isolation and a water pump flow control method. Background Art

[0002] In industrial automation and intelligent control systems, water pumps are key actuators, and their operating speed often needs to be dynamically adjusted based on on-site flow demand. A common control method involves an external system outputting an analog voltage signal (e.g., 0 to 10V). The pump control system receives this voltage signal and adjusts the pump speed accordingly, achieving precise control of fluid flow.

[0003] In existing technologies, to isolate and sample analog voltage signals, a transformer is typically used for electrical isolation. The analog signal is then processed by an MCU, and secure transmission of control signals is achieved through an optocoupler. Finally, serial communication is used for data exchange and execution control. While this design approach can achieve a fully functional control link, it suffers from complex system structure, high hardware costs, low response efficiency, and difficult maintenance. Furthermore, high-voltage signals (such as power supply or drive voltage) may exist within the pump control system. If not properly handled, the high voltage within the pump control system may be transmitted to the external control terminal through the input interface, posing a safety hazard to operation and maintenance personnel and upper-level equipment. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a voltage control circuit based on high-resistance isolation and a water pump flow control method. After the voltage is reduced by high-resistance isolation, the signal is amplified, and then the voltage is sampled and the water pump speed is calculated, thereby achieving the purpose of controlling the water pump flow. It not only isolates the high voltage through high resistance to protect the safety of the operator, but also can effectively isolate and collect analog voltage signals to realize the control of the water pump flow and reduce costs.

[0005] The first aspect of an embodiment of the present invention provides a voltage control circuit based on high-impedance isolation, including a high-impedance isolation signal sampling module for performing voltage isolation and voltage reduction on an input voltage signal; a signal conditioning module for amplifying and conditioning the isolated and reduced voltage signal; a sampling module for sampling the conditioned signal; and an MCU for calculating a target speed control value based on the sampled value to drive the speed of a water pump.

[0006] In one embodiment, the high-impedance isolated signal sampling module includes: a signal input end and a multi-stage voltage divider chain, wherein the signal input end is used to receive an external voltage; the multi-stage voltage divider chain includes a plurality of high-impedance resistors arranged in series, which are used to perform step-by-step voltage division on the input signal.

[0007] In one embodiment, the high-impedance isolation signal sampling module includes at least two independent channels, each of which includes a multi-stage voltage divider chain consisting of several high-impedance resistors connected in series; ceramic capacitors are arranged between the output ends of different stages of high-impedance resistors in the multi-stage voltage divider chain and the ground to form a π-type high-frequency filter network for suppressing high-frequency interference signals; a resistor spacing band or wiring spacing is provided between each of the independent channels to prevent interference between channels and avoid cross-coupling of multiple signals; and the high-impedance resistors included in each independent channel are different, forming an asymmetric independent channel, and a resistor is connected between each two asymmetric independent channels to force impedance balance.

[0008] In one embodiment, the high-impedance isolation signal sampling module further includes: a bypass resistor and a MOS transistor; one end of the bypass resistor is connected to the multi-stage voltage divider chain, and the other end is connected to the output node of the multi-stage voltage divider chain and the drain of the MOS transistor, the source of the MOS transistor is grounded, and the gate of the MOS transistor is connected to the control terminal of the MCU;

[0009] The MOS tube is used to receive the control signal of the MCU to conduct when the voltage is too high or suddenly changes, so that the bypass resistor forms a bypass branch, which bypasses part of the current around the part of the high-resistance resistor to reduce the voltage of the output node.

[0010] In one embodiment, the voltage control circuit further includes: a temperature sensing sampling module;

[0011] The temperature sensing sampling module includes at least one thermistor; the at least one thermistor is connected to the high-resistance isolation signal sampling module and is used to detect ambient temperature or device temperature rise.

[0012] In one embodiment, a voltage dividing point in the high-resistance isolation signal sampling module is connected to the signal conditioning module, and a voltage value of the voltage dividing point changes with a resistance value of the at least one thermistor.

[0013] In one embodiment, the high-impedance isolation signal sampling module further includes: a switch value input channel for receiving a switch value from a host computer and inputting the switch value signal into the high-impedance isolation signal sampling module for signal attenuation.

[0014] In one embodiment, the signal conditioning module includes a filtering circuit and a signal amplifying circuit; the filtering circuit is used to filter out contact jitter and high-frequency interference signals; the signal amplifying circuit includes an amplifier and a gain control network;

[0015] The amplifier is used to extract the voltage difference and suppress common-mode interference; the gain control network is used to set the amplification factor so that the voltage signal enters a preset linear range.

[0016] In one embodiment, the MCU is configured to determine a target speed control amount according to the sampling value, and control the speed of the water pump based on the target speed to achieve control of the water pump flow rate.

[0017] A second aspect of an embodiment of the present invention provides a water pump flow control method, comprising:

[0018] Get the sample value output by the sampling module;

[0019] determining a target speed control amount according to the sampled value;

[0020] The rotation speed of the water pump is controlled based on the target rotation speed control amount to achieve control of the water pump flow rate.

[0021] The present invention provides a voltage control circuit based on high-resistance isolation and a water pump flow control method, wherein the voltage control circuit based on high-resistance isolation includes a high-resistance isolation signal sampling module, which is used to isolate and reduce the voltage of the input voltage signal; a signal conditioning module, which is used to amplify and condition the isolated and reduced-voltage voltage signal; a sampling module, which is used to sample the above-mentioned conditioned signal; and an MCU, which is used to determine the target speed control amount based on the sampling value to drive the speed of the water pump.

[0022] The beneficial effects of the present invention are as follows: after the voltage is reduced by high-resistance isolation, the signal is amplified, and then the voltage is sampled and the water pump speed is determined, thereby achieving the purpose of controlling the water pump flow. Not only does the high voltage is isolated by high resistance to protect the safety of the operator, but the analog voltage signal can also be effectively isolated and collected to achieve the control of the water pump flow, and the cost can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of the circuit structure of a voltage control circuit based on high-resistance isolation provided by one embodiment of the present invention;

[0024] Figure 2 A schematic diagram of the circuit structure of a high-impedance isolation signal sampling module provided in one embodiment of the present application;

[0025] Figure 3 A schematic diagram of the circuit structure of a high-impedance isolation signal sampling module provided in yet another embodiment of the present application;

[0026] Figure 4 A schematic diagram of the circuit structure of a voltage control circuit based on high-resistance isolation provided in another embodiment of the present application. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to the accompanying drawings and examples.

[0028] See also Figure 1As shown, Figure 1 A schematic diagram of the circuit structure of a voltage control circuit based on high-resistance isolation provided by one embodiment of the present invention.

[0029] Depend on Figure 1 It can be seen that the voltage control circuit 100 based on high-impedance isolation provided in the embodiment of the present application includes a high-impedance isolation signal sampling module 110, which is used to isolate and reduce the voltage of the input voltage signal; a signal conditioning module 120, which is used to amplify and condition the isolated and reduced voltage signal; a sampling module 130, which is used to sample the above-mentioned conditioned signal; and an MCU 140, which is used to determine the target speed control amount based on the sampled value to drive the speed of the water pump. By using the high-impedance isolation signal sampling module to isolate and reduce the voltage of the input voltage signal, the safety of the operator can be effectively protected. After the signal is conditioned by the signal conditioning module, the speed of the water pump is determined based on the sampled value of the conditioned signal, which can achieve the effect of controlling the flow of the water pump. The structure is simple and easy to implement, and the cost of water pump flow control is effectively reduced.

[0030] It should be noted that in a water pump flow control system, there are typically multiple sources of analog and digital signals. These include, for example, high-voltage signals leaking from within the pump system; externally input analog speed control signals (such as a 0 to 10V control voltage) used to set the pump's operating speed; and externally input switch control signals used to execute start / stop commands or switch operating states. Furthermore, when the pump is subject to unstable pressure or temperature differences, this can also lead to an unstable operating environment. Due to the varying voltage levels and signal types, as well as potential interference and high-voltage coupling risks, connecting these signals directly to the main control MCU can easily lead to decreased system stability and even safety risks.

[0031] In order to solve the above problems, an embodiment of the present application provides a voltage control circuit based on high-resistance isolation to improve the safety of water pump operation.

[0032] Please participate Figure 2 , Figure 2 This is a schematic diagram of the circuit structure of a high-impedance isolation signal sampling module provided in one embodiment of the present application. Figure 2As can be seen, in this embodiment, the high-impedance isolated signal sampling module 110 includes a signal input terminal 111 for receiving an external voltage; a multi-stage voltage divider chain 112 comprising four high-impedance resistors (R1 to R4) arranged in series, which are used to gradually divide the input signal. This high-impedance isolated signal sampling module 110, with its four high-impedance resistors arranged in series, forms a multi-stage voltage divider chain. This not only reduces voltage but also provides current limiting and electrical isolation functions to prevent overcurrent damage to the circuit. It also divides high-voltage signals to a safe level, effectively preventing high-voltage output in the water pump control system, protecting both the circuit and the operator. It should be noted that in practical applications, the connection is not limited to four high-impedance resistors in series; any number of high-impedance resistors can be connected in series.

[0033] Specifically, several high-resistance resistors arranged in series can be evenly divided (e.g., each resistor has a resistance of 510Ω) or not. High-resistance resistors inherently limit current and provide basic isolation, reducing the risk of high-voltage "strikethrough" and preventing signal flow through a single resistor breakdown.

[0034] In the water pump flow control application scenario, an analog speed control signal (such as a 0 to 10V control voltage) is usually used to set the water pump operating speed. In this embodiment of the application, in order to ensure that the MCU can fully read all analog speed control signals corresponding to the 0 to 10V range, please refer to Figure 2 As shown, the high-impedance isolated signal sampling module 110 includes two independent channels, each of which is used to receive an analog speed control signal input. Each independent channel includes a multi-stage voltage divider chain 112 composed of a different number of high-impedance resistors for step-by-step voltage division of the input signal. Ceramic capacitors are provided between the output ends of the different stages of high-impedance resistors and ground. The capacitance of the ceramic capacitors is a small-capacitance ceramic capacitor (e.g., 2.2pF-10pF NP0) less than a certain capacitance value, forming a π-type high-frequency filter network. The ceramic capacitors can filter out the power frequency and electromagnetic interference on the analog signal line. The π-type high-frequency filter network forms a more stable impedance path for suppressing high-frequency interference signals. A resistor spacer 122 (which can also be a wiring spacer, not shown in the figure) is provided between each independent channel to prevent interference between signals and avoid cross-coupling of multiple signals. A resistor R12 is connected across each two asymmetric independent channels to force impedance balance between the two independent channels. The circuit structure provided in this embodiment is more practical for industrial analog interfaces. By setting up multiple asymmetric independent channels, the compatibility with the voltage range of the industrial standard speed regulation interface is improved, ensuring that the MCU can safely read the corresponding analog quantity.

[0035] It should be noted that, in practical applications, it is not limited to two independent channels, and may include more independent channels.

[0036] Furthermore, in practical applications, since the voltage divider chain formed by the multi-stage high-resistance resistors is a linear static network, assuming a 10V input voltage, a four-stage high-resistance resistor multi-stage voltage divider with a voltage divider ratio of 1 / 4 results in a 2.5V output voltage, which meets the MCU's allowable input range. However, if the input voltage exceeds a certain threshold, for example, 20V, the instantaneous output voltage at the high-resistance isolated signal sampling module output exceeds 5V after the multi-stage voltage divider implemented by the linear static network. This voltage exceeds the MCU's allowable input range and could potentially cause an overvoltage shock, impacting the stability of the entire system. Furthermore, when the input signal experiences a sudden change (such as a surge or EMI), the multi-stage voltage divider chain itself, due to its high resistance, cannot absorb the energy in a timely manner. Furthermore, parasitic capacitance near the output terminal of the PCB creates an RC delay effect, potentially causing a transient high voltage to appear at the output terminal. Furthermore, the larger the high-resistance resistor, the worse the surge immunity and the slower the response speed. Once there is a surge or induced voltage spike at the input end (such as a switching instantaneous induction of 10V to 20V), the voltage divider chain may be instantly pulled up. Although the average voltage is still in the safe zone, the transient may have exceeded the limit.

[0037] In order to prevent the above problems from occurring, in an embodiment of the present application, a MOS tube (such as N-MOOS or P-MOS) and a bypass resistor are further introduced into the multi-stage voltage divider chain of the high-resistance isolation signal sampling module 110 as a dynamically controllable branch resistor. When an instantaneous voltage is too high, the MCU detects the overvoltage at the sampling point, controls the MOS tube to be turned on, and discharges part of the voltage through the bypass resistor, thereby realizing dynamic voltage division ratio adjustment (improving voltage limiting capability), realizing dynamic voltage reduction capability, compensating for the deficiency of linear voltage division, and performing adaptive current limiting protection.

[0038] Specifically, see Figure 3 As shown, Figure 3 This is a circuit diagram of a high-impedance isolation signal sampling module provided by another embodiment of the present application. Figure 3 As can be seen, in this embodiment, the high-impedance isolated signal sampling module 110 includes: a signal input terminal 111 for receiving an external voltage; a multi-stage voltage divider chain 112, consisting of four high-impedance resistors R1 to R4 connected in series, for outputting a stepped-down signal; a bypass resistor R22; and a MOS transistor 113. One end of the high-impedance resistor R1 is connected to the external voltage input terminal, and the other end is connected to the high-impedance resistor R2. The other end of the high-impedance resistor R2 is connected to one end of the high-impedance resistor R3 and one end of the bypass resistor R22. The other end of the high-impedance resistor R3 is connected to one end of the high-impedance resistor R4. The other end of the high-impedance resistor R4 is connected to the sampling output node. The other end of the bypass resistor R22 is connected to the drain of the MOS transistor 113, and the source of the MOS transistor 113 is grounded. The gate of the MOS transistor 113 is connected to the control terminal of the MCU 140.

[0039] In this embodiment, the other end of high-resistance resistor R4 is connected to a sampling output node; this output node is also called a voltage divider point. This voltage divider point is used to input a voltage signal to subsequent circuits, and it forms a complete loop with ground. When the input voltage is normal (e.g., between 0 and 10V and without surges), current flows sequentially through high-resistance resistors R1 and R4. The voltage at the voltage divider point is reduced to a preset range (e.g., between 0 and 3.3V) by the voltage divider ratio. At this point, the corresponding MOS transistor 113 is turned off, and the bypass branch is inoperative. When the input voltage is too high or changes suddenly, MCU 140 detects the overvoltage and outputs a high level to turn on MOS transistor 113. This causes bypass resistor R22 to form a bypass branch, diverting some current around high-resistance resistors R3 and R4. This reduces the voltage at the voltage divider point and prevents damage to subsequent circuits. By controlling the conduction of the MOS transistors, dynamic voltage regulation, enhanced current limiting, and adaptive protection are achieved for the multi-stage voltage divider chain, effectively preventing damage or misjudgment caused by excessively high or sudden input signals.

[0040] It should be noted that in order to effectively prevent overheating caused by ambient temperature or device temperature rise signal, in the embodiment of the present application, please refer to Figure 4 The voltage control circuit 100 based on high-resistance isolation further includes a temperature sensing sampling module 150. It should be noted that, Figure 4 A schematic diagram of the circuit structure of a voltage control circuit based on high-resistance isolation provided in another embodiment of the present application.

[0041] Depend on Figure 4 It can be seen that the temperature sensing sampling module 150 includes a thermistor, and the thermistor is connected in series with the high-resistance isolation signal sampling module 110 to form a voltage divider. The thermistor is used to detect the ambient temperature or the temperature rise of the device, and the high-resistance isolation signal sampling module 110 is used to limit the current and isolate the input signal. In one embodiment, the voltage dividing point in the high-resistance isolation signal sampling module 110 is connected to the signal conditioning module 120. Since the voltage value of the voltage dividing point changes with the change of the thermistor, the MCU140 in the voltage control circuit can effectively achieve high-voltage isolation while realizing the detection of the ambient temperature or the temperature rise signal of the device, so as to realize protection mechanisms such as high temperature alarm and over-temperature shutdown. It should be noted that in the embodiment of the present application, at least one thermistor may be included, Figure 4 Only one thermistor is shown as an example.

[0042] It should be noted that in some application scenarios, the water pump may be affected by the pressure of the surrounding environment, which may affect the rotation speed of the water pump. In order to prevent the existence of some pressure in the surrounding environment from affecting the rotation speed of the water pump, a pressure sensing sampling module can also be added. Specifically, the pressure sensing sampling module is connected to the high-resistance isolation signal sampling module. After the collected pressure signal is transmitted to the high-resistance isolation signal sampling module, the voltage value output by the high-resistance isolation signal sampling module changes with the pressure value collected by the pressure sensing sampling module, so that the MCU140 in the voltage control circuit can effectively achieve high-voltage isolation while realizing the detection of the environmental pressure signal to realize protection mechanisms such as high-voltage alarm and over-voltage shutdown. Specifically, the pressure sensing sampling module is not shown in the drawings of the embodiments of the present application.

[0043] Furthermore, in water pump flow control scenarios, it's often necessary to receive switch signals from a host computer for executing start / stop commands or switching operating states. In this embodiment, the high-impedance isolated signal sampling module 110 is equipped with a switch input channel for receiving switch signals from the host computer, such as a switch input channel specifically designed for 24V industrial switch signals. The switch signal passes through the high-impedance isolated signal sampling module 110, undergoes isolation and voltage reduction processing, and then undergoes level identification, filtering, and amplification by the signal conditioning module 120. The signal is then converted to a TTL level (0V / 5V) recognizable by the MCU 140. The sampling module 130 then samples the signal and inputs it to the MCU 140. The MCU 140 reads this level and determines the switch state. For example, a high level (5V) indicates a signal is detected, closing the switch; a low level (0V) indicates no signal is detected, opening the switch. This ensures precise control of the water pump's on / off state while protecting circuit safety.

[0044] In one embodiment, the signal conditioning module 120 includes: a signal amplification circuit; the signal amplification circuit includes an amplifier and a gain control network; the amplifier is used to extract the voltage difference and suppress common-mode interference; the gain control network is used to set the amplification factor so that the voltage signal enters a preset linear range.

[0045] In one embodiment, the MCU 140 is configured to determine a target speed control amount according to the sampled value, and control the speed of the water pump based on the target speed to control the flow rate of the water pump.

[0046] In specific implementation, the sampling module 130 can periodically read various analog signals during the sampling control process, and dynamically judge the system status in combination with the multi-channel ADC conversion strategy of the MCU 140 to ensure the response speed and precision control performance of the water pump operation.

[0047] The beneficial effects of the present invention are as follows: The voltage control circuit based on high-resistance isolation provided includes: a high-resistance isolation signal sampling module for isolating and reducing the voltage of the input voltage signal; a signal conditioning module for amplifying and conditioning the isolated and reduced-voltage voltage signal; a sampling module for sampling the conditioned signal; and an MCU for calculating the target speed control value based on the sampled value to drive the speed of the water pump. After reducing the voltage through high-resistance isolation, the signal is amplified, and then the voltage is sampled and the water pump speed is calculated, thereby achieving the purpose of controlling the water pump flow. Not only does it protect the operator's safety by isolating the high voltage through high resistance, it can also effectively isolate and collect analog voltage signals to achieve water pump flow control, and can also reduce costs.

Claims

1. A voltage control circuit based on high-resistance isolation, characterized in that: It includes a high-impedance isolated signal sampling module for isolating and reducing the voltage of the input voltage signal; a signal conditioning module for amplifying and conditioning the isolated and reduced voltage signal; The sampling module is used to sample the conditioned signal; the MCU is used to calculate the target speed control value based on the sampled value and drive the speed of the water pump; The high-impedance isolated signal sampling module includes a signal input end and at least two independent channels, wherein the signal input end is used to receive an external voltage; each independent channel includes a multi-stage voltage divider chain consisting of several high-impedance resistors connected in series; ceramic capacitors are arranged between the output ends of different stages of high-impedance resistors in the multi-stage voltage divider chain and the ground to form a π-type high-frequency filter network for suppressing high-frequency interference signals; a resistor spacing band or wiring spacing is arranged between each of the independent channels to prevent interference between signals and avoid cross-coupling of multiple signals; and each independent channel includes different high-impedance resistors to form an asymmetric independent channel, and a resistor is connected between each two asymmetric independent channels to force impedance balance.

2. The voltage control circuit based on high-resistance isolation according to claim 1, characterized in that: The high-resistance isolation signal sampling module further includes: a bypass resistor and a MOS transistor; one end of the bypass resistor is connected to the multi-stage voltage divider chain, and the other end is connected to the drain of the MOS transistor; the source of the MOS transistor is connected to the output node of the multi-stage voltage divider chain and is also grounded; the gate of the MOS transistor is connected to the control terminal of the MCU; The MOS tube is used to receive the control signal of the MCU to conduct when the voltage is too high or suddenly changes, so that the bypass resistor forms a bypass branch, which bypasses part of the current around the part of the high-resistance resistor to reduce the voltage of the output node.

3. The voltage control circuit based on high-resistance isolation according to claim 2, characterized in that: The voltage control circuit further includes: a temperature sensing sampling module; The temperature sensing sampling module includes at least one thermistor; the at least one thermistor is connected to the high-resistance isolation signal sampling module and is used to detect ambient temperature or device temperature rise.

4. The voltage control circuit based on high-resistance isolation according to claim 3, characterized in that: The voltage dividing point in the high-resistance isolation signal sampling module is connected to the signal conditioning module, and the voltage value of the voltage dividing point changes with the resistance value of the at least one thermistor.

5. The voltage control circuit based on high-resistance isolation according to claim 4, characterized in that: The high-impedance isolation signal sampling module further includes: a switch value input channel for receiving a switch value signal from a host computer and inputting the switch value signal into the high-impedance isolation signal sampling module for signal attenuation.

6. The voltage control circuit based on high-resistance isolation according to claim 5, characterized in that: The signal conditioning module includes a filtering circuit and a signal amplifying circuit; the filtering circuit is used to filter out contact jitter and high-frequency interference signals; the signal amplifying circuit includes an amplifier and a gain control network; The amplifier is used to extract the voltage difference and suppress common-mode interference; the gain control network is used to set the amplification factor so that the voltage signal enters a preset linear range.

7. The voltage control circuit based on high-resistance isolation according to claim 6, characterized in that: The MCU is used to determine a target speed control amount according to the sampling value, and control the speed of the water pump based on the target speed control amount to achieve control of the water pump flow rate.

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