Starting circuit of electromagnetic valve and control method of starting circuit

Abstract

The invention provides a starting circuit of an electromagnetic valve and a control method of the starting circuit. The starting circuit comprises a preset detection module, a boost module and a step-down module. One end of the preset detection module is connected with input voltage, and the control end of the preset detection module controls one of the boost module and the buck module to be output and connected to a power supply line of the electromagnetic valve. The preset detection module has a first control state and a second control state in sequential time in each period of controlling the electromagnetic valve, and the first control state is used for inputting the input voltage into the boosting module to be boosted and then outputting the boosted input voltage to the electromagnetic valve for starting the electromagnetic valve; and the second control state is that after the first control state exceeds the preset duration, the input voltage is switched to be reduced by the voltage reduction module and then is output to the electromagnetic valve for keeping the state after the electromagnetic valve is started. In this way, the electromagnetic valve is simple in structure, the electromagnetic valve can be rapidly started, temperature rise is effectively prevented by reducing the working voltage of the electromagnetic valve after the electromagnetic valve is started, and the service life of the electromagnetic valve is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of solenoid valve driving, and in particular to a solenoid valve starting circuit and a control method thereof. Background Art

[0002] In the prior art, some household appliances with liquid pipeline control usually rely on solenoid valves to complete starting, holding and disconnection. The solenoid valve requires a large electromagnetic force during startup. In order to ensure the electromagnetic force required when the solenoid valve is started, there are two ways to design the solenoid valve. The first way is to increase the number of windings. However, due to the limited internal space of the solenoid valve, the number of windings is limited. Another way is to increase the starting current, but this method will cause the temperature of the solenoid valve to rise, shortening the life of the solenoid valve, and even risk burning out after long-term use.

[0003] After the solenoid valve is started, the solenoid valve in the household appliance usually operates with the power supply voltage as the working voltage, which consumes a lot of energy and affects the service life of the solenoid valve. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and to provide a solenoid valve starting circuit and a control method thereof.

[0005] The technical solution adopted by the present invention is as follows: comprising a preset detection module, a boost module and a buck module;

[0006] One end of the preset detection module is connected to the input voltage, and the control end thereof controls the boost module and the buck module to select one output to be connected to the power supply line of the solenoid valve; the preset detection module has a first control state and a second control state in a time sequence in each cycle of controlling the solenoid valve, wherein the first control state is to input the input voltage to the boost module for boosting and then output it to the solenoid valve for starting the solenoid valve; the second control state is that after the first control state exceeds the preset time length, the input voltage is switched to the buck module for bucking and then output to the solenoid valve for maintaining the state after the solenoid valve is started.

[0007] Through this setting, the inventor discovered that the holding state of the solenoid valve after starting does not actually need to maintain the same electromagnetic force as at the moment of starting, and the holding state is the main working state of the solenoid valve during its working process. If the solenoid valve operates at a higher working voltage in the holding state, the solenoid valve will be in a high energy consumption state for a long time, affecting the service life of the solenoid valve.

[0008] Preferably, it further comprises a rectifier module, which is arranged between the input voltage and the preset detection module and is used to rectify the input voltage.

[0009] Preferably, the boost ratio of the output to the input of the boost module is 1<a≤1.5.

[0010] Preferably, the voltage reduction ratio between the output and input of the voltage reduction module is 0.5<b≤1.

[0011] Preferably, the boost module comprises an inductor L1, a capacitor C1, a first switch S1 and a transistor Q1, the first switch S1, the inductor L1 and the capacitor C1 are connected in series in sequence, the transistor Q1 is connected in parallel with the capacitor C1, one end of the first switch S1 is connected to the output end of the rectifier module, and one end of the capacitor C1 is grounded;

[0012] Both ends of capacitor C1 are connected to the power supply line of the solenoid valve.

[0013] Preferably, the boost module includes a diode D1, the anode of the diode D1 is connected to one end of the inductor L1, and the cathode of the diode D1 is connected to one end of the capacitor C1; the boost module includes a coil L2, and the coil L2 is connected in parallel with C1.

[0014] Preferably, the structure of the voltage-reducing module is a voltage-dividing circuit added on the basis of the voltage-reducing module, and the voltage-dividing circuit is used to reduce the output voltage across the capacitor C1.

[0015] Preferably, when the preset detection module is in the first control state, the preset detection module controls the first switch S1 to be closed, the second switch S2 to be opened, and the transistor Q1 to be closed first and then opened;

[0016] When the preset detection module is in the second control state, the preset detection module controls the first switch S1 to be opened, the second switch S2 to be closed, and the transistor Q1 to be opened.

[0017] Preferably, a method for starting and controlling a solenoid valve comprises the following steps:

[0018] S1, when starting, input voltage is input to the boost module for boosting, and input to the power supply line of the solenoid valve, starting the solenoid valve to open;

[0019] S2. After a preset time, the output of the boost module is cut off through the preset detection module, and the input voltage is input to the buck module and to the power supply line of the solenoid valve, so as to keep the solenoid valve in an open state;

[0020] S3, the input voltage is cut off and the solenoid valve is closed.

[0021] The beneficial effects of the present invention are as follows: the present invention has a simple structure. First, the voltage is increased by the boost module so that the solenoid valve can quickly complete the opening action. At the same time, the preset detection module calculates the boost time. If the boost time exceeds the preset time, the preset detection module switches the first control state in the boost state to the second control state in the step-down state for controlling the step-down module. The solenoid valve can still remain in the open state in the second control state. At the same time, due to the voltage drop, the power consumption of the solenoid valve is reduced, electric energy is saved, and the temperature rise is effectively reduced, thereby extending the service life of the solenoid valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying creative labor, other drawings obtained based on these drawings still belong to the scope of the present invention.

[0023] Figure 1 It is the circuit principle diagram of the present invention;

[0024] Figure 2 It is a principle block diagram of the present invention;

[0025] Figure 3 It is a schematic diagram of the change of input voltage and time of the solenoid valve of the present invention;

[0026] Figure 4 It is a flow chart of the working state of the present invention;

[0027] In the figure, 1-input voltage, 2-rectifier module, 3-preset detection module, 4-boost module, 5-step-down module, 6-solenoid valve. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings.

[0029] It should be noted that all expressions using "first" and "second" in the embodiments of the present invention are for distinguishing two non-identical entities with the same name or non-identical parameters. It can be seen that "first" and "second" are only for the convenience of expression and should not be understood as limitations on the embodiments of the present invention. The subsequent embodiments will not explain this one by one.

[0030] The directions and positions mentioned in the present invention, such as "upper", "lower", "front", "back", "left", "right", "inside", "outside", "top", "bottom", "side", etc., are only for reference to the directions or positions of the drawings. Therefore, the directions and positions used are for explaining and understanding the present invention, but not for limiting the scope of protection of the present invention.

[0031] To solve the above problems, Figures 1 to 4 As shown, the embodiment of the present application provides a solenoid valve start-up circuit and a control method thereof, including a preset detection module 3, a boost module 4 and a buck module 5;

[0032] The preset detection module 3 includes:

[0033] A controller, used for timing the boosting time. When the solenoid valve is connected to the power supply, the controller starts timing the boosting time from zero and compares the boosting time with the preset time.

[0034] The switch control module determines whether to switch the switch state according to the comparison result of the boosting time and the preset time, and switches the first control state in the boosting state to the second control state in the bucking state of the buck control module 5 when the boosting time exceeds the preset time;

[0035] It can be understood that the controller of this embodiment can use all chips that can realize the preset detection function, and the switch control module can use electronic components with switching functions. For example, the controller can use STM32F103, and the switch control module can use electronic components such as relays, transistors and diodes.

[0036] One end of the preset detection module 3 is connected to the input voltage 1, and the control end of the preset detection module 3 controls the boost module 4 and the buck module 5 respectively and selects one output to be connected to the power supply line of the solenoid valve 6; the preset detection module 3 has a first control state and a second control state in time sequence in each cycle of controlling the solenoid valve 6, wherein the first control state is to input the input voltage 1 to the boost module 4 for boosting and then output it to the solenoid valve 6 for starting the solenoid valve 6; the second control state is that after the first control state exceeds the preset time length, the input voltage 1 is switched to the buck module 5 for bucking and then output to the solenoid valve 6, which is used to maintain the state of the solenoid valve 6 after starting.

[0037] It is understandable that, since the solenoid valve 6 is usually composed of a powered coil, a static iron core and a moving iron core, when a large current is applied to the powered coil, the static iron core and the moving iron core are attracted, and after the static iron core and the moving iron core are attracted, only a small current is needed to maintain the attracted state of the static iron core and the moving iron core, wherein when the static iron core and the moving iron core are in the initial state, the solenoid valve 6 is in a closed state; when the static iron core and the moving iron core are in the attracted state, the solenoid valve 6 is in an open state. A large starting voltage is applied to the solenoid valve 6 through the boost module 4 so that the solenoid valve 6 starts quickly. Since the static iron core and the moving iron core in the solenoid valve 6 are attracted, only a small power supply voltage is needed to satisfy the attracted state of the static iron core and the moving iron core. Therefore, when the solenoid valve 6 is started, the working voltage of the solenoid valve 6 is reduced from a relatively high starting voltage to a holding voltage lower than the input voltage 1 through the step-down module 5. Thereafter, the solenoid valve 6 works to maintain the voltage, thereby realizing low power consumption operation of the solenoid valve 6.

[0038] When the starting voltage is used as the working voltage of the solenoid valve 6, the working time of the solenoid valve 6 is the boost time. The preset detection module 3 has a switch selection function and a detection function. By detecting the boost time and comparing the boost time with the preset time, if the boost time exceeds the preset time, the preset detection module 3 switches the first control state in the boost state to the second control state in the step-down state for controlling the step-down module 5; if the boost time does not exceed the preset time, the present invention is always in the first control state in the boost state.

[0039] The preset time length is a relatively reasonable value obtained after many tests. Ideally, the preset time length is equal to the time difference from the moment the solenoid valve 6 is started to the moment the electromagnet inside the solenoid valve 6 is attracted. In practice, in order to leave a certain amount of time for the device, the preset time length is slightly greater than the time difference.

[0040] Through the above settings, the solenoid valve can be started quickly, and after the solenoid valve is started, it can maintain its started state with a lower working voltage, with low power consumption, and effectively reduce temperature rise, thereby extending the service life of the solenoid valve.

[0041] like Figure 3 The first control state is at 0-T a Time period, the second control state is in T a -T0 time period. After T0, the solenoid valve 6 is in a power-off state. If the solenoid valve 6 needs to be restarted, the solenoid valve 6 needs to be powered on again.

[0042] It also includes a rectifier module 2, which is arranged between the input voltage 1 and the preset detection module 3, and is used to rectify the input voltage 1. It can be understood that after rectifying the input voltage 1, the input voltage 1 signal can be stable, ensuring that the subsequent solenoid valve 6 can operate normally.

[0043] The boost ratio of the output to the input of the boost module 4 is 1<a≤1.5. Specifically, it can be 1.2 or 1.3. It can be understood that the value of the boost ratio can be changed, and the boost ratio is related to the duty cycle. The boost ratio is proportional to the duty cycle. The duty cycle of the boost module 4 in the present invention is the closing time of the transistor Q1 / the disconnecting time of the transistor Q1. When the closing time of the transistor Q1 is longer, the more energy is stored in the inductor L1. When the transistor Q1 is disconnected, the inductor L1 and the input voltage 1 both charge the capacitor C1, so that the larger the output voltage across the capacitor C1, the larger the input voltage of the solenoid valve 6, so that the solenoid valve 6 can be opened quickly.

[0044] The step-down ratio of the output to the input of the step-down module 5 is 0.5<b≤1, specifically 0.7 or 0.9. It is understandable that the value of the step-down ratio can be changed, and when the values ​​of some components in the step-down module 5 change, the step-down ratio changes accordingly.

[0045] The preset time length is related to the model of the inductor L1; it can be understood that the present application is connected to the power supply U0, after passing through the rectifier module 2, at this time the first switch S1 is turned on, the second switch S2 is turned off, when the transistor Q1 is turned on, the U0 voltage passes, at this time the inductor L1 is charged, when the inductor L1 current reaches a, generally a<0.2A, the transistor Q1 is turned off, at this time the voltage flowing through the coil L2 is equivalent to a*the resistance of the coil L2, recorded as aU0, at this time 1<a≤1.5, at the same time the capacitor C1 is charged after the transistor Q1 is turned off, for example model 10 000uF capacitor, through 0.2A current, 220V voltage, about 55ms can be fully charged, when the capacitor C1 is fully charged, the transistor Q1 is disconnected, the first switch S1 is disconnected, and the second switch S2 is turned on. After the conduction, the voltage passes through the voltage divider resistor R1 and passes through the coil L2. At this time, the actual voltage applied to the coil L2 is equivalent to bU0, which reduces the voltage applied to the coil L2, reduces the power consumption of the coil L2, and prolongs the working life of the coil L2. The role of the capacitor C1 is to ensure that the discharge is powered to the coil L2 at the moment of the switch switching. It can be seen that the preset duration of this application is related to the time when the inductor L1 current reaches a and the time when the capacitor C1 is fully charged.

[0046] The boost module 4 includes an inductor L1, a capacitor C1, a first switch S1 and a transistor Q1, wherein the inductor L1 is connected in series with the first switch S1, one end of the first switch S1 is connected to the output end of the rectifier module 2, one end of the inductor L1 is respectively connected to one end of the transistor Q1 and one end of the capacitor C1, and the other ends of the transistor Q1 and the other ends of the capacitor C1 are both grounded. It can be understood that the control of the voltage across the capacitor C1 is mainly achieved by the conversion of the charge and discharge state of the inductor L1.

[0047] The boost module 4 includes a diode D1, the anode of the diode D1 is connected to the other end of the inductor L1, and the cathode of the diode D1 is connected to one end of the capacitor C1. The diode D1 ensures that the current in the circuit can only flow in one direction, protects other components in the circuit from damage, and provides reverse voltage protection to protect other components in the circuit from damage.

[0048] The boost module 4 includes a coil L2 , and the coil L2 is connected in parallel with C1 .

[0049] The step-down module 5 adds a resistor R1 and a second switch S2 on the basis of the step-up module 4, which simplifies the circuit and reduces the volume and cost.

[0050] The step-down module 5 includes a resistor R1 and a second switch S2, wherein the resistor R1 and the second switch S2 are connected in series, the other end of the resistor R1 is connected to one end of the capacitor C1, and one end of the second switch S2 is connected to the output end of the rectifier module 2. The resistor R1 is used as a voltage-dividing resistor to reduce the voltage on the coil L2, that is, to reduce the output voltage.

[0051] The rectifier module 2 adopts a bridge full-wave rectifier circuit, which rectifies both the positive and negative half-cycles of the AC voltage to obtain a stable DC output. The input voltage is converted into a positive and negative sine wave through a bridge full-wave rectifier circuit. The input voltage in the present invention refers to the power supply for daily life, because household appliances with liquid pipeline control usually directly use daily electricity as input voltage in actual use. The rectifier module 2 stabilizes the direction of the current flowing to the coil L2, and also ensures that the voltage direction at both ends of the coil L2 remains unchanged; at the same time, the frequency of the current is not changed, and the inductor L1, coil L2 and capacitor C1 in the circuit are not affected.

[0052] In the embodiment of the present invention, the start-up circuit of the solenoid valve 6 starts and maintains the solenoid valve 6 by controlling the switching on and off of different switches. The specific working process is as follows:

[0053] (1) When the first switch S1 is closed, the second switch S2 is open, and the transistor Q1 is closed, the input voltage charges the inductor L1. At this time, the direction of the induced voltage across the inductor L1 is positive on the left and negative on the right.

[0054] (2) When the first switch S1 is closed, the second switch S2 is opened, and the transistor Q1 changes from the closed state to the open state, the current in the circuit changes from large to small, and the induced current in the inductor L1 is consistent with the direction of the circuit current, flowing from left to right. Because the induced voltage of the inductor L1 is in opposite directions to the induced current, the induced voltage across the inductor L1 is negative on the left and positive on the right. At this time, the inductor L1 and the input voltage 1 act as the circuit power supply to charge the capacitor C1 and the coil L2. At this time, the voltage across the coil L2 is the sum of the voltage of the inductor L1 and the external power supply 1. The voltage increases and the output voltage is aUo.

[0055] (3) When the first switch S1 changes from a closed state to an open state, the second switch S2 changes from an open state to a closed state, and the transistor Q1 changes from a closed state to an open state, the resistor R1 is connected to the circuit. Since the current direction does not change, the voltage direction across the resistor R1 is negative on the left and positive on the right, which leads to a decrease in the voltage across the coil L2. At this time, the output voltage is bUo.

[0056] The switch states of the above steps (1) and (2) are changed to the first control state, and the switch state of the above step (3) is changed to the second control state. The total time of step (1) and step (2) is the boost time, and the ratio of step (1) to the boost time is the duty cycle, which is proportional to the boost ratio. After completing the above steps (1) to (2), the electromagnetic valve 6 can be quickly started. After the electromagnetic valve 6 is started, the preset detection module 3 detects the boost time and determines whether the boost time exceeds the preset time. If it exceeds the preset time, the first control state is switched to the second control state.

[0057] A method for starting and controlling a solenoid valve comprises the following steps:

[0058] S1, when starting, input voltage 1 is input to boost module 4 for boosting, and input to the power supply line of the solenoid valve, and the solenoid valve 6 is started to open;

[0059] S2, after a preset time, the output of the boost module 4 is cut off, and the input voltage 1 is input to the step-down module 5 and to the power supply line of the solenoid valve 6, so that the solenoid valve 6 is kept in an open state;

[0060] S3, the input voltage 1 is powered off and the solenoid valve 6 is closed.

[0061] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A solenoid valve starting circuit, characterized in that: It includes a preset detection module, a voltage boost module and a voltage drop module; One end of the preset detection module is connected to the input voltage, and the control end of the preset detection module controls the boost module and the buck module respectively and selects one output to be connected to the power supply line of the solenoid valve; the preset detection module has a first control state and a second control state in time sequence in each cycle of controlling the solenoid valve, wherein the first control state is to input the input voltage to the boost module for boosting and then output it to the solenoid valve for starting the solenoid valve; the second control state is that after the first control state runs for more than a preset time, the input voltage is switched to the buck module for bucking and then output to the solenoid valve for maintaining the state after the solenoid valve is started.

2. The solenoid valve starting circuit according to claim 1, characterized in that: It also includes a rectifier module, which is arranged between the input voltage and the preset detection module and is used to rectify the input voltage.

3. The solenoid valve starting circuit according to claim 1, characterized in that: The boost ratio of the output to the input of the boost module is 1<a≤1.

5.

4. The solenoid valve starting circuit according to claim 1, characterized in that: The voltage reduction ratio between the output and input of the voltage reduction module is 0.5<b≤1.

5. The solenoid valve starting circuit according to claim 2, characterized in that: The boost module includes an inductor L1, a capacitor C1, a first switch S1 and a transistor Q1, wherein the first switch S1, the inductor L1 and the capacitor C1 are connected in series in sequence, the transistor Q1 is connected in parallel with the capacitor C1, one end of the first switch S1 is connected to the output end of the rectifier module, and one end of the capacitor C1 is grounded; Both ends of capacitor C1 are connected to the power supply line of the solenoid valve.

6. The solenoid valve starting circuit according to claim 5, characterized in that: The boost module includes a diode D1, the anode of the diode D1 is connected to one end of the inductor L1, and the cathode of the diode D1 is connected to one end of the capacitor C1; the boost module includes a coil L2, and the coil L2 is connected in parallel with C1.

7. The solenoid valve starting circuit according to claim 5 or 6, characterized in that: The structure of the step-down module is a voltage divider circuit added on the basis of the step-up module, and the voltage divider circuit is used to reduce the output voltage across the capacitor C1.

8. The solenoid valve starting circuit according to claim 1, characterized in that: When the preset detection module is in the first control state, the preset detection module controls the first switch S1 to be closed, the second switch S2 to be opened, and the transistor Q1 to be closed first and then opened; When the preset detection module is in the second control state, the preset detection module controls the first switch S1 to be opened, the second switch S2 to be closed, and the transistor Q1 to be opened.

9. A method for starting and controlling a solenoid valve, characterized in that: include: The solenoid valve startup control method is used to implement the solenoid valve startup circuit of any one of claims 1 to 8; S1, when starting, input voltage is input to the boost module for boosting, and input to the power supply line of the solenoid valve, and the solenoid valve is started to open; S2. After a preset time, the output of the boost module is cut off through the preset detection module, and the input voltage is input to the buck module and to the power supply line of the solenoid valve, so as to keep the solenoid valve in an open state; S3, the input voltage is cut off and the solenoid valve is closed.

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