Control circuit for reducing power consumption of solenoid valve

Abstract

A control circuit for reducing the power consumption of a solenoid valve comprises an input power supply, a step-down module, a delay module, and a temperature control module. The input end of the step-down module is connected to the input power supply, and the output end of the step-down module is respectively connected to the input end of the temperature control module and the input end of the delay module. The output end of the step-down module is grounded via the coil of the solenoid valve through a circuit that prevents current from flowing in reverse. The output end of the temperature control module is connected to the feedback end of the step-down module, so that the step-down module adjusts the output voltage according to the temperature of the coil of the solenoid valve. The input power supply and the output end of the delay module are connected to the power supply end of the coil of the solenoid valve via a switching tube. The ground end of the coil of the solenoid valve is grounded. The cathode of a diode is connected to the power supply end of the coil of the solenoid valve, and the anode of the diode is connected to the ground end of the coil of the solenoid valve. The control circuit can effectively reduce the power consumption of the solenoid valve, reduce the temperature rise of the coil of the solenoid valve, and increase the service life of the solenoid valve.

Description

Technical Field

[0001] The present invention relates to the technical field of solenoid valve control, and in particular to a control circuit for reducing the power consumption of a solenoid valve. Background Art

[0002] A solenoid valve is a control element commonly used in hydraulic and pneumatic systems. For normally closed solenoid valves, the structure and operation of the solenoid valve indicate that when the valve is closed, the gap between the valve core and the coil is large, requiring a larger magnetic field to open the valve, and therefore a larger current. However, after the solenoid valve opens, the gap between the valve core and the coil decreases, requiring a smaller magnetic field strength to maintain the valve core position. Therefore, once the solenoid valve is open, only a smaller current is required to maintain the valve core position. If the current drawn by the solenoid valve during the hold state is not reduced, the temperature of the solenoid valve coil will increase significantly, thus shortening its service life.

[0003] At present, the commonly used methods to reduce the power consumption of solenoid valves are: one is to control the solenoid valve by using an MCU to generate a PWM signal with a certain frequency and duty cycle. Although this method can reduce the electromagnetic power consumption to a certain extent, the PWM signal will cause high-frequency vibration and noise in the solenoid valve, which will also affect the life of the solenoid valve. In addition, the cost of the control circuit generated by the MCU to generate the PWM signal is relatively high; the other is to combine a delay circuit with a step-down circuit, and use the delay circuit to keep the solenoid valve in an open state with a lower voltage output by the step-down circuit. However, since the solenoid valve is in a held state for a long time, the temperature of the solenoid valve coil will increase accordingly, and the resistance of the solenoid valve coil will also increase with the temperature. If the output voltage of the step-down circuit remains unchanged, the current flowing through the solenoid valve coil will decrease. If the coil current decreases to a certain value, the solenoid valve will not be able to remain in an open state. Summary of the Invention

[0004] The purpose of the present invention is to address the deficiencies in the prior art and provide a control circuit for reducing the power consumption of a solenoid valve, which can effectively reduce the power consumption of the solenoid valve, reduce the coil temperature rise of the solenoid valve, and increase the service life of the solenoid valve.

[0005] The technical solution of the present invention is: a control circuit for reducing the power consumption of a solenoid valve, comprising an input power supply, a step-down module, a delay module, and a temperature control module, wherein the input end of the step-down module is connected to the input power supply, and the output end of the step-down module is respectively connected to the input end of the temperature control module and the input end of the delay module, and the output end of the step-down module is grounded via a circuit that prevents reverse current flow through the coil of the solenoid valve, the output end of the temperature control module is connected to the feedback end of the step-down module, so that the step-down module adjusts the output voltage according to the temperature of the coil of the solenoid valve, the output end of the input power supply and the delay module are connected to the power supply end of the coil of the solenoid valve through a switching tube, the ground end of the coil of the solenoid valve is grounded, the cathode of a diode is connected to the power supply end of the coil of the solenoid valve, and the anode of the diode is connected to the ground end of the coil of the solenoid valve.

[0006] Furthermore, the temperature control module includes a temperature sensor, a transistor, and a voltage regulator diode. The input end of the temperature sensor is connected to the output end of the step-down module via a sixth resistor, the output end of the temperature sensor is connected to the base of the transistor via a fourth resistor, the collector of the transistor is connected to the feedback end of the step-down module, the emitter of the transistor is grounded via a fifth resistor, the ground end of the temperature sensor is grounded, the anode of the voltage regulator diode is connected to the ground end of the temperature sensor, and the cathode of the voltage regulator diode is connected to the input end of the temperature sensor.

[0007] Furthermore, the transistor is an NPN transistor.

[0008] Furthermore, the step-down module includes a DC / DC converter, a diode, an electrolytic capacitor, and an inductor. The input end of the DC / DC converter is connected to the input power supply, the enable end of the DC / DC converter is connected to the input power supply via a first resistor, the drive end of the DC / DC converter outputs the voltage from the output end of the step-down module via the first capacitor and the inductor in sequence, the source end of the DC / DC converter is connected between the first capacitor and the inductor, the feedback end of the DC / DC converter is connected to the output end of the step-down module via a second resistor, and is grounded via a third resistor, the cathode of the diode is connected to the source end of the DC / DC converter, the positive pole of the electrolytic capacitor is connected to the output end of the step-down module, and the ground end of the DC / DC converter, the anode of the diode, and the negative pole of the electrolytic capacitor are all grounded.

[0009] Furthermore, a third capacitor is connected in parallel across both ends of the electrolytic capacitor.

[0010] Furthermore, the delay module includes a first inverter, a second inverter, a resistor, and a capacitor. The input end of the first inverter is connected to the output end of the step-down module via the resistor and is grounded via the capacitor. The output end of the first inverter is connected to the input end of the second inverter. The output end of the second inverter is connected to the gate of the switching tube. The source of the switching tube is connected to the input power supply, and the drain of the switching tube is connected to the power supply end of the coil of the solenoid valve.

[0011] Furthermore, a diode is connected in parallel at both ends of the resistor, the cathode of the diode is connected to the output end of the step-down module, and the anode of the diode is connected to the input end of the first inverter.

[0012] Furthermore, a diode is provided between the switch tube and the solenoid valve, the anode of the diode is connected to the drain of the switch tube, and the cathode of the diode is connected to the power supply end of the coil of the solenoid valve.

[0013] Furthermore, the switch tube is a P-MOS tube.

[0014] Furthermore, the circuit for preventing the reverse flow of current is a diode, the anode of the diode is connected to the output end of the step-down module, and the cathode of the diode is connected to the power supply end of the coil of the solenoid valve.

[0015] The beneficial effects of the above technical solution are as follows: This circuit controls the on / off switching of the first switch tube through a delay module. When the solenoid valve is opened, the delay module generates a control signal to turn on the first switch tube. At this time, the voltage across the solenoid valve coil is the input power supply, and the high current provided by the input power supply causes the solenoid valve to open. When the delay module reaches the delay time, the delay module generates a control signal to turn off the first switch tube. The voltage of the input power supply is reduced by the step-down module to power the solenoid valve. At this time, the current flowing through the solenoid valve coil is reduced, allowing the solenoid valve to maintain an open state with a low current, thereby effectively reducing the power consumption of the solenoid valve, reducing the temperature rise of the solenoid valve coil, and increasing the service life of the solenoid valve. In addition, this circuit provides a temperature control module between the step-down module and the delay module. This allows the output voltage of the temperature control module to increase as the temperature of the solenoid valve coil increases. This increases the output voltage of the step-down module, thereby increasing the voltage across the solenoid valve coil. This ensures that the current flowing through the solenoid valve coil does not change with temperature, ensuring that the solenoid valve can remain open for a long time.

[0016] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a principle block diagram of the present invention;

[0018] Figure 2 1 is a specific circuit diagram of the present invention;

[0019] Figure 3 This is a circuit structure diagram of the step-down module of the present invention. DETAILED DESCRIPTION

[0020] See also Figures 1 to 3 An embodiment of a control circuit for reducing the power consumption of a solenoid valve includes an input power supply VIN, a step-down module, a delay module, and a temperature control module. The input end of the step-down module is connected to the input power supply VIN, and the output end of the step-down module is connected to the input end of the temperature control module and the input end of the delay module, respectively. The output end of the step-down module is grounded via a circuit that prevents reverse current flow through the coil of the solenoid valve. The circuit that prevents reverse current flow is a diode D5, the anode of which is connected to the output end of the step-down module, and the cathode of which is connected to the power supply end of the coil of the solenoid valve, for protecting the step-down module. The output end of the temperature control module is connected to the feedback end of the step-down module, so that the step-down module adjusts the output voltage according to the temperature of the solenoid valve coil, so that the output voltage increases as the temperature of the solenoid valve coil increases, so that the current flowing through the solenoid valve coil does not change with the temperature increase, thereby ensuring that the solenoid valve can remain in an open state for a long time. The output end of the input power supply and the delay module is connected to the power supply end of the solenoid valve coil via a switch tube Q2. The ground end of the solenoid valve coil is grounded. The cathode of a diode D6 is connected to the power supply end of the solenoid valve coil, and the anode of the diode D6 is connected to the ground end of the solenoid valve coil. The diode D6 in this embodiment can be a Schottky diode to prevent the reverse voltage generated when the solenoid valve coil is powered off from damaging other components.

[0021] The temperature control module of this embodiment includes a temperature sensor T1, a transistor Q1, and a Zener diode D2. The transistor Q1 of this embodiment is an NPN transistor, and the temperature sensor T1 is a TC1046 model. The input end of the temperature sensor T1 is connected to the output end of the step-down module via a sixth resistor R6, and the output end of the temperature sensor T1 is connected to the base of the transistor Q1 via a fourth resistor R4. The collector of the transistor Q1 is connected to the feedback end of the step-down module, and the emitter of the transistor Q1 is grounded via a fifth resistor R5. The ground end of the temperature sensor T1 is grounded, the anode of the Zener diode D2 is connected to the ground end of the temperature sensor T1, and the cathode of the Zener diode D2 is connected to the input end of the temperature sensor T1. As the coil temperature of the solenoid valve increases, the output voltage of the temperature sensor T1 increases, and the current flowing through the transistor Q1 and the fifth resistor R5 increases. The transistor Q1 and the fifth resistor R5 can be regarded as a dynamic resistor R that changes with temperature. T As a result, the output voltage of the step-down module increases as the coil temperature of the solenoid valve increases.

[0022] The step-down module of this embodiment includes a DC / DC converter IC1, a diode D1, an electrolytic capacitor C4, and an inductor L1. The DC / DC converter IC1 of this embodiment adopts TPS5430. The input end of the DC / DC converter IC1 is connected to the input power supply VIN. The enable end of the DC / DC converter IC1 is connected to the input power supply VIN via the first resistor R1. The driving end of the DC / DC converter IC1 outputs the voltage from the output end of the step-down module via the first capacitor C1 and the inductor L1 in sequence. The source terminal of the C converter IC1 is connected to the first capacitor C1 and the inductor L1. The feedback terminal of the DC / DC converter IC1 is connected to the output terminal of the step-down module via the second resistor R2 and is grounded via the third resistor R3. The cathode of the diode D1 is connected to the source terminal of the DC / DC converter IC1. The positive electrode of the electrolytic capacitor C4 is connected to the output terminal of the step-down module. The ground terminal of the DC / DC converter IC1, the anode of the diode D1, and the negative electrode of the electrolytic capacitor C4 are all grounded. The two ends of the electrolytic capacitor C4 are connected in parallel with the third capacitor C3. When the DC / DC converter IC1 is in steady state operation, the voltage at the feedback terminal is the reference voltage 1.22V. Its output voltage is determined by the external voltage divider resistor fed back to the feedback terminal, that is, it is determined by the second resistor R2 and the third resistor R3. The transistor Q1 and the fifth resistor R5 of the above-mentioned temperature control module are equivalent to the dynamic resistance R T It is connected in parallel with the third resistor R3, so that the output voltage of the voltage reduction module changes with the coil temperature of the solenoid valve.

[0023] The delay module of this embodiment includes a first inverter U1, a second inverter U2, a resistor R7, and a capacitor C5. The input end of the first inverter U1 is connected to the output end of the step-down module via the resistor R7 and is grounded via the capacitor C5. The output end of the first inverter U1 is connected to the input end of the second inverter U2. The output end of the second inverter U2 is connected to the gate of the switch tube Q2. The source of the switch tube Q2 is connected to the input power supply VIN, and the drain of the switch tube Q2 is connected to the power supply end of the coil of the solenoid valve. A diode D4 is provided between the switch tube Q2 and the solenoid valve. The anode of the diode D4 is connected to the drain of the switch tube Q2, and the cathode is connected to the power supply end of the coil of the solenoid valve. The switch tube Q2 of this embodiment is a P-MOS tube. The delay module is composed of a resistor R7 and a capacitor C5 to form an RC delay circuit. When the solenoid valve is started, the delay module sends a control signal to turn on the switch tube Q2, and the input power supply VIN supplies power to the solenoid valve. After the solenoid valve is started, the delay module reaches the delay time and controls the switch tube Q2 to turn off. The output voltage of the step-down module is used to power the solenoid valve, so that the solenoid valve remains open with a small current. In practice, the resistor R7 and capacitor C5 with appropriate parameters can be selected as needed to ensure that the delay time meets the delay requirements.

[0024] In this embodiment, a diode D3 is connected in parallel across the resistor R7. The cathode of the diode D3 is connected to the output of the step-down module, and the anode of the diode D3 is connected to the input of the first inverter U1. The diode D3 forms a discharge circuit for the capacitor C5. After the switch Q2 is turned off, the charge of the capacitor C5 is discharged in a timely manner to avoid affecting the delay time of the delay module. The diode D3 can be a Schottky diode.

[0025] The working principle of this circuit is as follows: When the solenoid valve is started, the output voltage of the step-down module charges the capacitor C5 through the resistor R7. The delay module outputs a low level to the gate of the switch tube Q2, turning on the switch tube Q2. At this time, the input power supply VIN provides voltage to the solenoid valve, and the current flowing through the coil of the solenoid valve is a large current, which starts the solenoid valve with a large current.

[0026] After the solenoid valve is started, when the delay module reaches the delay time and the capacitor C5 is fully charged, the delay module outputs a high level to the gate of the switch tube Q2, turning off the switch tube Q2. At this time, the output voltage of the step-down module is used to power the solenoid valve, and the current flowing through the coil of the solenoid valve is a small current, so that the solenoid valve remains in the open state with a small current.

[0027] During the operation of the solenoid valve, the temperature of the solenoid valve coil increases, and the output voltage of the temperature sensor T1 changes with the temperature of the solenoid valve coil, driving the transistor Q1, so that the transistor Q1, the fifth resistor R5 and the third resistor R3 form a shunt. The feedback end of the DC / DC converter IC1 outputs a constant voltage. Therefore, the transistor Q1 and the fifth resistor R5 can be regarded as a dynamic resistor R that changes with temperature. T , the final output voltage of the buck module can be calculated by the following formula:

[0028]

[0029] It can be seen that the temperature of the solenoid valve coil increases with the running time, the output voltage of the temperature sensor T1 increases, and the current flowing through the transistor Q1 and the fifth resistor R5 also increases, making the equivalent resistance R T According to the above formula, the output voltage of the step-down module will increase synchronously to ensure that the current flowing through the coil of the solenoid valve does not change with temperature.

[0030] This circuit has a simple structure. Through this circuit, a large current can be used to start the solenoid valve, and a small current can be used to keep the solenoid valve in an open state, thereby effectively reducing the power consumption of the solenoid valve, reducing the temperature rise of the solenoid valve coil, and increasing the service life of the solenoid valve. During the operation of the solenoid valve, it is ensured that the current of the coil will not decrease with the increase of temperature, so that the solenoid valve can operate stably for a long time.

Claims

1. A control circuit for reducing the power consumption of a solenoid valve, comprising an input power supply, a voltage reduction module, and a delay module, characterized in that: It also includes a temperature control module, wherein the input end of the step-down module is connected to the input power supply, the output end of the step-down module is respectively connected to the input end of the temperature control module and the input end of the delay module, and the output end of the step-down module is grounded via the coil of the solenoid valve through a circuit that prevents current from flowing in reverse. The output end of the temperature control module is connected to the feedback end of the step-down module, so that the step-down module adjusts the output voltage according to the temperature of the coil of the solenoid valve, the input power supply and the output end of the delay module are connected to the power supply end of the coil of the solenoid valve via a switch tube, the ground end of the coil of the solenoid valve is grounded, the cathode of a diode is connected to the power supply end of the coil of the solenoid valve, and the anode of the diode is connected to the ground end of the coil of the solenoid valve; The temperature control module includes a temperature sensor, a transistor, and a voltage regulator diode. The input end of the temperature sensor is connected to the output end of the step-down module via a sixth resistor, the output end of the temperature sensor is connected to the base of the transistor via a fourth resistor, the collector of the transistor is connected to the feedback end of the step-down module, the emitter of the transistor is grounded via a fifth resistor, the ground end of the temperature sensor is grounded, the anode of the voltage regulator diode is connected to the ground end of the temperature sensor, and the cathode of the voltage regulator diode is connected to the input end of the temperature sensor.

2. The control circuit for reducing power consumption of a solenoid valve according to claim 1, characterized in that: The transistor is an NPN transistor.

3. The control circuit for reducing power consumption of a solenoid valve according to claim 1, characterized in that: The step-down module includes a DC / DC converter, a diode, an electrolytic capacitor, and an inductor. The input end of the DC / DC converter is connected to the input power supply, the enable end of the DC / DC converter is connected to the input power supply via a first resistor, the drive end of the DC / DC converter outputs the voltage from the output end of the step-down module via the first capacitor and the inductor in sequence, the source end of the DC / DC converter is connected between the first capacitor and the inductor, the feedback end of the DC / DC converter is connected to the output end of the step-down module via a second resistor, and is grounded via a third resistor, the cathode of the diode is connected to the source end of the DC / DC converter, the positive electrode of the electrolytic capacitor is connected to the output end of the step-down module, and the ground end of the DC / DC converter, the anode of the diode, and the negative electrode of the electrolytic capacitor are all grounded.

4. The control circuit for reducing power consumption of a solenoid valve according to claim 3, characterized in that: A third capacitor is connected in parallel to both ends of the electrolytic capacitor.

5. The control circuit for reducing power consumption of a solenoid valve according to claim 1, characterized in that: The delay module includes a first inverter, a second inverter, a resistor, and a capacitor. The input end of the first inverter is connected to the output end of the step-down module via the resistor and is grounded via the capacitor. The output end of the first inverter is connected to the input end of the second inverter. The output end of the second inverter is connected to the gate of the switching tube. The source of the switching tube is connected to the input power supply, and the drain of the switching tube is connected to the power supply end of the coil of the solenoid valve.

6. The control circuit for reducing power consumption of a solenoid valve according to claim 5, characterized in that: A diode is connected in parallel at both ends of the resistor, the cathode of the diode is connected to the output end of the step-down module, and the anode of the diode is connected to the input end of the first inverter.

7. The control circuit for reducing power consumption of a solenoid valve according to claim 5, characterized in that: A diode is provided between the switch tube and the electromagnetic valve, wherein the anode of the diode is connected to the drain of the switch tube, and the cathode of the diode is connected to the power supply end of the coil of the electromagnetic valve.

8. The control circuit for reducing power consumption of a solenoid valve according to claim 1, characterized in that: The switch tube is a P-MOS tube.

9. The control circuit for reducing power consumption of a solenoid valve according to claim 1, characterized in that: The circuit for preventing the reverse flow of current is a diode, the anode of the diode is connected to the output end of the step-down module, and the cathode of the diode is connected to the power supply end of the coil of the solenoid valve.

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