Control circuit capable of rapidly discharging residual current of electric proportional valve coil

Abstract

A control circuit for quickly discharging residual current of a coil of an electric proportional valve comprises a control circuit board matched with the electric proportional valve, a voltage stabilizing module, a processing circuit, a first adjusting circuit, a second adjusting circuit and an output circuit, wherein the signal output end of a flow sensor is electrically connected with the signal input end of the control circuit board; the voltage stabilizing module, the processing circuit, the first adjusting circuit, the second adjusting circuit and the output circuit are installed in an element box of the electric proportional valve and electrically connected. In the charging and discharging control process of the valve core, as the proportional valve coil can sense the voltage in the opposite direction at the moment of power supply disconnection, the high voltage sensing end of the coil can be connected with the power supply through the fast recovery diode, and the voltage is quickly clamped to be close to the voltage of the power supply; the low-voltage end of the coil is connected with the ground through the driving tube, the two ends of the coil, the power supply and the ground form a loop, energy in the coil is rapidly discharged, and the action frequency of the driving coil of the electric proportional valve is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to drive circuit technical field, especially a control circuit that can quick discharge electric proportional valve coil remanent current. BACKGROUND

[0002] Electric proportional valve is a kind of electric actuator widely used in industrial automation control, mainly for realizing the accurate control to fluid medium, when specific work, electric proportional valve is based on the control circuit board of single-chip microcontroller etc., the voltage or current analog quantity voltage signal output of corresponding sensor (such as the dynamic change voltage signal output of flow sensor with pipeline flow) is collected, then signal processing, output PWM signal to the drive circuit signal input end of electric proportional valve, the current size of the MOS drive tube of drive circuit controls the power input end of the valve core of electric proportional valve, to realize the valve core degree of electric proportional valve open-close size reaches the value (such as flow sensor detects the relatively big fluid flow in corresponding pipeline, the signal voltage output of flow sensor is relatively big, control circuit board outputs relatively low PWM signal to the drive circuit signal input end of electric proportional valve, the valve core opening degree of electric proportional valve is small, and fluid output flow becomes relatively small, flow sensor detects the relatively small fluid flow in corresponding pipeline, the signal voltage output of flow sensor is relatively small, control circuit board outputs relatively high PWM signal to the drive circuit signal input end of electric proportional valve, the valve core opening degree of electric proportional valve is big, and fluid output flow becomes relatively big, keeps the fluid flow of electric proportional valve output at the value set by control circuit board)

[0003] Although the existing drive circuit matched with the electric proportional valve controls the working mode of the electric proportional valve, and meets the fluid control needs to some extent, it still has the following technical problems due to the limitation of structure. Specifically, after the control circuit board of the existing electric proportional valve outputs a PWM signal, the drive circuit directly drives the driving coil of the valve core by using a drive tube for fast switching control, that is, the purpose of controlling the size of the driving coil current is achieved by using the chopper control and integral effect on the power supply (to achieve the effect of approximate constant current drive). This method is feasible for low-speed drive of the electric proportional valve control, but it cannot achieve good control effect for fast drive proportional valve which needs to control the valve core action frequently (such as medical equipment which needs to use high-speed proportional valve to quickly control the flow, and the response period of the proportional valve needs to reach 1ms). Because, in the case of closing the power supply circuit, the discharge speed of the driving coil is slow (commonly known as slow freewheeling) during the discharge stage of the driving coil, and the response speed of the valve core (the electric proportional valve has a reset spring, and the driving coil and the reset spring drive the valve core to move up or down) is relatively slow. Therefore, the existing electric proportional valve drive circuit is only suitable for low-speed proportional valve coil driving, and has limitations in application. Practical new type content

[0004] In order to overcome the drawbacks of the existing electric proportional valve drive circuit due to the limitation of structure and function, the utility model provides a control circuit which can quickly charge and discharge the coil under the joint action of related circuits, especially the discharge speed is relatively faster, improves the action frequency of the electric proportional valve driving coil, and provides technical support for the reliable and stable work of the fast drive proportional valve.

[0005] The technical scheme adopted by the utility model to solve the technical problems is:

[0006] The control circuit capable of quickly discharging the coil residual current of the electric proportional valve comprises a control circuit board matched with the electric proportional valve, a voltage stabilizing module, a signal output end of a flow sensor and a signal input end of the control circuit board are electrically connected, and further comprises a processing circuit, a first adjusting circuit and a second adjusting circuit, and an output circuit; the voltage stabilizing module, the processing circuit, the first adjusting circuit and the second adjusting circuit and the output circuit are installed in a component box of the electric proportional valve, a power output end of the voltage stabilizing module and power input ends of the processing circuit, the first adjusting circuit, the second adjusting circuit and the output circuit are electrically connected; a PWM signal output end of the control circuit board and signal input ends of the processing circuit and the second adjusting circuit are electrically connected, a signal output end of the processing circuit and a signal input end of the first adjusting circuit are electrically connected, a signal output end of the second adjusting circuit and a signal input end of the output circuit are electrically connected, power output ends of the output circuit and the first adjusting circuit and a power input end of a driving coil of the electric proportional valve are electrically connected, and a signal output end of the first adjusting circuit and a signal input end of the output circuit are electrically connected.

[0007] Further, the processing circuit comprises a driving chip, a diode, a resistor, a capacitor, one end of the first resistor is connected with the HIN port and the LIN port of the driving chip, the VCC port of the driving chip is connected with one end of the first capacitor, one end of the second capacitor and the positive electrode of the diode, the negative electrode of the diode is connected with one end of the second resistor, the other end of the second resistor is connected with one end of the third capacitor and the VB port of the driving chip, the VS port of the driving chip is connected with the other end of the third capacitor, and the other end of the first capacitor is connected with the other end of the second capacitor and the COM port of the driving chip.

[0008] Further, the first adjusting circuit comprises a diode, a resistor, a driving tube and a capacitor, the negative electrode of the first diode is connected with one end of the first resistor, the negative electrode of the second diode is connected with one end of the second resistor, the positive electrode of the first diode is connected with one end of the third resistor and the gate of the first driving tube, the drain of the first driving tube is connected with one end of the first capacitor and one end of the second capacitor, the other end of the third resistor is connected with the source of the first driving tube and the drain of the second driving tube, the positive electrode of the first diode is connected with the other end of the second resistor, one end of the fourth resistor and the source of the second driving tube, and the other end of the fourth resistor is connected with the source of the second driving tube, the other end of the first capacitor and the other end of the second capacitor.

[0009] Further, the second adjusting circuit comprises resistors and transistors connected in electrically, the first resistor one end and the second resistor one end, the first transistor base, the first transistor collector and the third resistor one end, the second transistor base, the second transistor collector and the fourth resistor one end, the third transistor base and the fourth transistor base, the third diode emitter and the fourth transistor emitter, the capacitor one end and the third resistor one end and the fourth resistor one end and the third transistor collector, the capacitor other end and the second resistor other end and the first transistor emitter and the second transistor emitter and the fourth transistor emitter.

[0010] Further, the output circuit comprises diodes and driving tubes connected in electrically, resistors, the first resistor one end and the second resistor one end, the driving tube gate, the second resistor other end and the driving tube source, the driving tube drain and the diode anode.

[0011] Compared with the prior art, the utility model has the advantages that: the utility model has improved the coil working mode of the direct switch control electric proportional valve of the existing driving tube, in application, the direction of current can be switched during the valve core charging (power on) and discharging control process, especially during the discharging process, because the proportional valve coil will induce a reverse voltage at the moment of power disconnection (driving tube is closed), the high voltage end of the coil is connected with the power supply through the fast recovery diode, the voltage is quickly clamped to the size of the power supply voltage, the low voltage end of the coil is connected with the ground through the driving tube, the loop of the two ends of the coil and the power supply and the ground is formed, the energy in the coil is quickly discharged (commonly known as fast freewheeling), the action frequency of the electric proportional valve driving coil is improved, which provides favorable technical support for the reliable and stable work of the fast driving proportional valve. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 It is the structural diagram schematic of the utility model.

[0013] Figure 2 It is the circuit diagram of the utility model.

[0014] Figure 3 It is the actual product graph of the utility model. DETAILED DESCRIPTION

[0015] Figure 1 、 2The control circuit capable of quickly releasing the residual current of the electric proportional valve coil is shown, including the control circuit board U1 matched with the electric proportional valve, the voltage stabilizing module U3, and the signal output end of the flow sensor U4 and the signal input end of the control circuit board U1 are electrically connected, and the control circuit further has a processing circuit, a first adjusting circuit and a second adjusting circuit, and an output circuit; the voltage stabilizing module, the processing circuit, the first adjusting circuit and the second adjusting circuit, and the output circuit are installed on the circuit board in the element box of the electric proportional valve.

[0016] Figure 1 、 2As shown, the processing circuit includes the driving chip U2, diode D3, resistors R5, R3, capacitors C3, C4, C5 connected by circuit board wiring. One end of the first resistor R5 is connected with the HIN port 2 pin and LIN port 3 pin of the driving chip U2, the VCC port 1 pin of the driving chip U2 is connected with one end of the first capacitor C3, one end of the second capacitor C4 and the positive electrode of the diode D3, the negative electrode of the diode D3 is connected with one end of the second resistor R3, the other end of the second resistor R3 is connected with one end of the third capacitor C5 and the VB port 8 pin of the driving chip U2, the VS port 6 pin of the driving chip U2 is connected with the other end of the third capacitor C5, the other end of the first capacitor C3 is connected with the other end of the second capacitor C4 and the COM port 4 pin of the driving chip U2. The first adjusting circuit includes diodes D1, D5 and resistors R1, R2, R6, R9, driving tubes Q1, Q2 and capacitors C1, C2 connected by circuit board wiring. The negative electrode of the first diode D1 is connected with one end of the first resistor R1, the negative electrode of the second diode D5 is connected with one end of the second resistor R6, the positive electrode of the first diode D1 is connected with one end of the third resistor R2 and the gate of the first driving tube Q1, the drain of the first driving tube Q1 is connected with one end of the first capacitor C1 and one end of the second capacitor C2, the other end of the third resistor R2 is connected with the source of the first driving tube Q1 and the drain of the second driving tube Q2, the positive electrode of the first diode D5 is connected with the other end of the second resistor R6, one end of the fourth resistor R9 and the source of the second driving tube Q2, the other end of the fourth resistor R9 is connected with the source of the second driving tube Q2, the other end of the first capacitor C1 and the other end of the second capacitor C2. The second adjusting circuit includes resistors R13, R14, R15, R16 and triodes Q4, Q5, Q6, Q7, capacitor C12 connected by circuit board wiring. One end of the first resistor R15 is connected with one end of the second resistor R16 and the base of the first triode Q6, the collector of the first triode Q6 is connected with one end of the third resistor R14 and the base of the second triode Q5, the collector of the second triode Q5 is connected with one end of the fourth resistor R13 and the bases of the third triode Q4 and the fourth triode Q7, the emitter of the third triode Q4 is connected with the emitter of the fourth triode Q7, one end of the capacitor C12 is connected with one end of the third resistor R14, one end of the fourth resistor R13 and the collector of the third triode Q4, the other end of the capacitor C12 is connected with the other end of the second resistor R16 and the emitters of the first triode Q6, the second triode Q5 and the fourth triode Q7. The output circuit includes diode D2, driving tube Q3 and resistors R7, R11 connected by circuit board wiring. One end of the first resistor R7 is connected with one end of the second resistor R11 and the gate of the driving tube Q3, the other end of the second resistor R11 is connected with the source of the driving tube Q3, the drain of the driving tube Q3 is connected with the positive electrode of the diode D2.

[0017] Figure 1 ,2 As shown, the power input terminals 1 and 2 of the voltage regulator module U3 are connected to the two poles of the 220V AC power supply via wires. The power output terminals 3 and 4 of the voltage regulator module U3 are connected to the two ends of the power input capacitor C3 of the processing circuit and the two ends of the power input capacitor C1 of the first adjustment circuit.

[0018] The two ends of capacitor C12 at the power input terminal of the second adjustment circuit, the cathode of diode D2 at the power input terminal of the output circuit, and the source of driver transistor Q3 are respectively...

[0019] The PWM signal output terminal of the control circuit board U1 and the signal input terminal of the processing circuit are connected by wires. The other end of resistor R5 and the signal input terminal of the second adjustment circuit are connected by wires. The signal output terminal of the processing circuit, pins 7, 6, and 5 of the driver chip U2, and the signal input terminal of the first adjustment circuit, the cathode of diode D1, the source of driver transistor Q1, and the cathode of diode D5 are connected by wires. The emitter of transistor Q4 and the signal input terminal of the output circuit are connected by wires. The power output terminal of the output circuit, the drain of driver transistor Q3, the other end of resistor R2 and the power input terminal of the electric proportional valve drive coil DC are connected by wires. The drain of driver transistor Q1 and the signal input terminal of the output circuit are connected by wires.

[0020] Figure 1 , 2As shown, the voltage stabilizing module U3 is powered on and outputs a stable 12V DC power to the power input terminals of the processing circuit, the first regulating circuit, the second regulating circuit and the output circuit, and the above-mentioned circuits are powered on. During operation, the electric proportional valve is controlled by the control circuit board U1 based on a single-chip microcomputer, and collects the voltage or current analog voltage signal output by the corresponding sensor U4 (such as a dynamic voltage signal output by a flow sensor according to the dynamic change of the pipeline flow), and then processes the signal and outputs a PWM signal to the other end of the resistor R5 and the resistor R15. The control signal is processed by the processing circuit, and then output to the first regulating circuit and the second regulating circuit. The first regulating circuit and the second regulating circuit process the signal and output the signal to the output circuit, and the output circuit further outputs the power to the power input terminal of the valve core DC of the electric proportional valve (the flow sensor detects that the fluid flow in the corresponding pipeline is relatively large, and the signal voltage output by the flow sensor is relatively large. The output circuit outputs a relatively low current signal to the signal input terminal of the drive circuit of the electric proportional valve, and the opening degree of the valve core of the electric proportional valve is small, and the fluid output flow becomes relatively small. The flow sensor detects that the fluid flow in the corresponding pipeline is relatively small, and the signal voltage output by the flow sensor is relatively small. The output circuit outputs a relatively high current signal to the signal input terminal of the drive circuit of the electric proportional valve, and the opening degree of the valve core of the electric proportional valve is large, and the fluid output flow becomes relatively large, so that the fluid flow output by the electric proportional valve is kept at the value set by the control circuit board). In the circuit, the PWM signal is a switching signal, which only has two states of high and low. The drive chip U2 only responds to the two states of the PWM signal. When the PWM signal is at a high level, the signal is input to the 2 and 3 pins of the drive chip U2. The 2 pin controls the 7 pin HO to output a high level, and the 3 pin controls the 5 pin LO to output a low level. The 7 pin HO outputs a high level signal through the current limiting resistor R1 and is connected to the gate of the drive tube Q1, which is turned on (conducting). At this time, the power supply 12V starts to charge the proportional valve coil DC through the drive tube Q1. When the 3 pin of the drive chip U2 controls the 5 pin LO to output a low level, it is connected to the gate of the drive tube Q2 through the current limiting resistor R6, which is turned off. At this time, the drive tube Q2 does not work and does not participate in the charging process of the proportional valve. At the same time, the PWM signal is also input to the current limiting resistor R15, which drives the push-pull circuit composed of transistors Q6, Q5, Q4 and Q7, and is connected to the gate of the drive tube Q3 through the current limiting resistor R7, which is turned on (conducting). After the drive tube Q3 is turned on, the negative electrode of the proportional valve coil DC is connected to the ground through the drive tube Q3. At this time, the power supply forms a complete charging circuit through the drive tube Q1, the proportional valve coil and the drive tube Q3.When the PWM signal is low, the signal is input to the 2, 3 pins of the driving chip U2, the 2 pin controls the 7 pin HO to output low level, the 3 pin controls the 5 pin LO to output high level, the 7 pin HO output low level signal is connected to the gate of the driving tube Q1 through the current limiting resistor R1, the driving tube Q1 is closed, at this time the driving tube Q1 does not work and does not participate in the discharge process of the proportional valve DC, the 3 pin controls the 5 pin LO to output high level, which is connected to the gate of the driving tube Q2 through the current limiting resistor R6, Q2 is opened, the negative pole of the induced voltage of the proportional valve coil DC is directly grounded, at the same time, the PWM signal is also input to the current limiting resistor R15, which drives the push-pull circuit composed of the triodes Q6, Q5, Q4 and Q7, which is connected to the gate of the driving tube Q3 through the current limiting resistor R7, the driving tube Q3 is closed, at this time the driving tube Q3 does not work and does not participate in the discharge process, but the negative pole of the fast recovery diode D2 is directly connected to the power supply 12V, because its conduction voltage drop is only 0.7V, at this time D2 will quickly clamp the high voltage generated by the proportional valve coil to 12V+0.7V, and rapidly discharge the energy to the power supply end, charge the capacitors C1 and C2, because of the direct current isolation characteristic of the capacitor, the energy generated by the proportional valve coil is discharged through D2, C1 and C2 to the ground, and then flows back to the negative pole of the proportional valve coil through Q2, forming a complete discharge circuit. The discharged energy is stored in the capacitors C1 and C2, which stores energy for the next charging process. Thus, the working process of the PWM signal controlling the charging and discharging of the proportional valve coil is introduced.

[0021] Figure 1 、 2As shown, in the new type, the main innovation is to improve the coil operation mode of the existing driving pipe directly switch control electric proportional valve, control the charging and discharging circuit of the proportional valve coil DC. H bridge circuit (H bridge circuit is because the new type takes the proportional valve coil as the center, its upper left has Q1, its lower left has Q2, its upper right has D2, and its lower right has Q3, which looks like the character H, so it is called H bridge circuit in the industry) can switch the direction of current during charging and discharging control, especially during discharging, because the proportional valve coil DC is closed by the driving pipe when the power is disconnected (the specific driving pipe Q1 and Q3 are switched from the on state to the off state), a reverse voltage will be induced, at this time the circuit will connect the induced high voltage end of the coil DC to the 3 pin of the power module U3 through the fast recovery diode D2, and the voltage will be quickly clamped to the size of the output power supply voltage of the power module U3, and the low voltage end of the coil DC will be connected to the ground through the driving pipe Q2, at this time the two ends of the coil DC form a loop with the 4 pin of the power module U3, and the energy in the coil is quickly discharged (commonly known as fast freewheeling), which prepares for the next period of charging; because the energy (residual current) in the coil DC can be quickly discharged (commonly known as fast freewheeling) after being turned off, the action frequency of the electric proportional valve driving coil is improved, which provides favorable technical support for the reliable and stable operation of the fast driving proportional valve.

[0022] Figure 1 , 2As shown, in particular work, the control circuit board U3 generated PWM signal, through the resistance R5 current limiting into the drive chip U2 2 feet and 3 feet, drive chip U2 2 feet and 3 feet are control signal input pin, 2 feet is high level effective, when the input signal is high level, U2 control 7 feet HO output high level, otherwise, then output low level; U2 3 feet is low level effective, when the input signal is low level, 5 feet LO output high level, otherwise, output low level, the embodiment here will drive chip U2 2, 3 two pins are directly connected, using their logic mutual exclusion relationship, can control the drive tube Q1 and Q2, make two drive tube Q1 and Q2 always work in mutual exclusion state (mutual exclusion effect is to ensure that Q1 and Q2 cannot work at the same time, because if two drive tube work at the same time in the open state, the power supply and ground will be directly connected, will directly burn the drive circuit). In the processing circuit, capacitor C3, C4 is the power supply filter capacitor of drive chip U2; Diode D3, resistor R3, capacitor C5 three constitute bootstrap circuit, specifically, diode D3 in the circuit when charging capacitor C5 conduction, drive chip U2 6 feet voltage because of the opening of drive tube Q1, the voltage rises to 12V power supply voltage, due to the one-way conductivity of diode D3, at this time, diode D3 is in cutoff state, the voltage difference between the two ends of capacitor C5 always exists, at this time, drive chip U2 8 feet VB port can get 12V+12V=24V common mode voltage, for the required voltage of drive tube Q1, Q2 (if at this time, Q1 gate common mode voltage is 12V, assuming Q1 can open, then its source voltage will rise to the power supply voltage 12V, gate and source voltage is the same, at this time, Q1 cannot be opened, because the drive tube can work quickly and stably, the gate voltage should be higher than the source voltage, so there is the above D3, R, C5 together constitute the bootstrap circuit, let U2 8 feet VB have 24V common mode voltage, higher than the voltage of the source at this time 12V); Resistor R1 is the drive limiting resistor of drive tube Q1 gate, resistor R2 is the drive tube Q1 pull down resistor, can keep low level when the gate of drive tube Q1 has no drive voltage, prevent drive tube Q1 misdirected on cause circuit anomaly; D1 diode is a fast discharge diode, when U2 7 feet HO is low, D1 can quickly pull down the gate pin voltage of Q1 to ground (let the gate voltage of Q1 be low, quickly close the drive tube); Resistor R6 is the drive limiting resistor of drive tube Q2 gate, resistor R9 is the drive tube Q2 pull down resistor, can keep low level when the gate of drive tube Q2 has no drive voltage, prevent drive tube Q2 misdirected on cause circuit anomaly; D5 diode is a fast discharge diode, when U2 5 feet LO is low, D5 can quickly pull down the gate pin voltage of Q2 to ground (let the gate voltage of Q2 be low, quickly close the drive tube).In the output circuit, diode D2 is a fast recovery diode, working in proportional valve coil DC discharge state, through diode D2, proportional valve coil DC can be induced to produce high voltage fast and power loop discharge (can be proportional valve coil above the induced high voltage clamping in 12V+0.7V), at the same time, the release of coil DC energy, also can supply power to power module U3, so the power supply voltage with H bridge circuit is more stable, the whole machine power consumption is lower, and the power supply working efficiency is higher. In the processing circuit, the second adjusting circuit, the output circuit and the like, since the driving chip U2 can only control two driving tubes Q1 and Q2, the driving tube Q3 is driven by a separate driving circuit, since the driving tube Q3 and Q1 need to be opened or closed at the same time, the PWM signal is connected to the resistor R15, and the resistor R15 is the driving current limiting resistor of the transistor Q6; the resistor R6 is a pull-down resistor, which provides a low level for Q6 when there is no control signal input; the resistor R14 is a pull-up resistor, which provides a high level input signal for the transistor Q5; the function of the transistor Q5 is a reverser, which together with the transistor Q6 forms a level matching circuit, converts the 5V TTL level signal of PWM into a 12V driving signal, and does not change the control logic timing state (the control logic timing state does not change the 5V-TTL level PWM signal timing, which is exactly the same as the 12V level PWM signal timing); the resistor R13 is a pull-up resistor, which provides a high level for Q4; the transistors Q4 and Q7 form a classic push-pull output circuit, which can provide strong push-pull current for the gate of the driving tube Q3, and is an ideal driving circuit for controlling the gate of the driving tube Q3; the resistor R7 is the gate drive current limiting resistor of the driving tube Q3. In operation, when the PWM signal output by the control circuit board U3 is high, the 7 pin HO of the driving chip U2 outputs high, and the driving tube Q1 is opened (when the PWM signal is high, the 2 and 3 pins of U2 are high at the same time, the 2 pin high level signal is input to the gate of Q1 after being processed by the internal circuit of U2, Q1 is opened, and D1 diode does not work because it is in reverse blocking state, the 3 pin high level signal is input to the gate of Q2 after being processed by the internal circuit of U2, Q2 is closed, and D5 diode is in reverse conduction because the gate voltage of Q2 is 12V, D5 can clamp the voltage to 0.7V quickly, and Q2 is closed quickly), at the same time, the driving tube Q3 is also opened (when the PWM signal is high, the PWM signal is input to the base of the transistor Q6 through the current limiting resistor R15, Q6 is opened, and the 3 pin voltage of Q6 is low because Q6 works in switching state, the base of Q5 connected with Q6 is also low at this time, and Q5 is in off state.The 3-pin of Q5 is high at this time because the 3-pin level is pulled up to 12V by the R13 pull-up resistor, the bases of Q4 and Q7 are connected together to form a push-pull circuit, the 1-pin of Q4 is 12V at this time (the role of the R13 pull-up resistor), Q4 works in the voltage follower state at this time, the E voltage of the 2-pin is 12V-0.7V, this high voltage is input to the gate of Q3 through the current-limiting resistor R7, which ensures the rapid opening of Q3), at this time, the power supply charges the proportional valve coil DC, when the PWM output by the control circuit board U3 is a low-level signal, the drive tubes Q1 and Q3 are immediately closed, at the same time, because the drive chip U2 has a dead zone control function, it needs to wait for more than 20ns before the 5-pin LO of the drive chip U2 outputs a high level to safely open the drive tube Q2 (the 5-pin LO of U2 outputs a high level, the signal is input to the gate of Q2 through the current-limiting resistor R6, and Q2 is safely opened. Diode D5 does not work at this time because it is in the off state, the 7-pin HO of U2 outputs a low level at this time, the signal is connected to the gate of Q1 through the current-limiting resistor R1, diode D1 works in the on state at this time, which clamps the driving voltage 12V on Q1 to 0.7V quickly, quickly closes the drive tube Q1), and quickly discharges the high-voltage energy generated by the proportional valve coil DC, which is actually equivalent to reverse charging the power supply to improve power supply efficiency.

[0023] Figure 1 、 2 As shown in the figure, in the new type, when the control signal is H (high) in the control process, the drive tubes Q1 and Q3 are opened, at this time, the current flows from the 12V power supply through the drive tube Q1, then through the proportional valve coil DC, and then through the drive tube Q3 to the ground, forming a charging circuit to supplement the energy of the coil, when the control signal is L (low) for discharging, the drive tubes Q1 and Q3 are closed, at this time, the drive tube Q2 needs to be opened, and the fast recovery diode D2 is directly connected to the power supply at the same time, at this time, the proportional valve coil DC acts as a new power supply, and the energy discharge circuit is the fast recovery diode D2, the 12V power supply, the capacitors C1 and C2, the drive tube Q2, and the proportional valve coil DC low voltage end (negative electrode). In the transition moment of the charging and discharging of the coil DC, because the drive tubes Q1 and Q2 are connected in series, if the control is directly switched, the drive tubes Q1 and Q2 will be opened at the same time, which is equivalent to the power supply 12V being directly connected to the ground, because the impedance in the circuit loop at this time is almost 0 ohm, a large current will be generated, which will cause the drive tubes Q1 and Q2 to be directly burned out, therefore, the new type also needs to add a dead zone control logic, that is, after the charging circuit is completely closed, the discharging circuit is opened, in order to realize this function, the new type uses the drive chip U2, which is a commonly used chip in the field of motors and other applications, this chip with a dead zone control logic is used to realize safe charging and discharging switching control.

[0024] The basic principle and main features of the present application and the advantages of the present application are shown and described above. For those skilled in the art, it is obvious that the present application is limited to the details of the above exemplary embodiments, and can be realized in other specific forms without departing from the spirit or basic characteristics of the present application. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application.

[0025] In addition, it should be understood that, although the present application is described in the form of an embodiment, the embodiment does not only contain one independent technical solution, and the description manner of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in the embodiments can also be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A control circuit capable of quickly discharging the residual current of the coil of an electric proportional valve, comprising a control circuit board matched with the electric proportional valve, a voltage stabilizing module, and a signal output end of a flow sensor electrically connected with a signal input end of the control circuit board, characterized in that, Also have processing circuit, first regulating circuit and second regulating circuit, output circuit; The voltage stabilizing module, processing circuit, first regulating circuit and second regulating circuit, output circuit are installed in the component box of electric proportional valve, and the power supply output end of voltage stabilizing module and the power supply input end of processing circuit, first regulating circuit, second regulating circuit, output circuit are electrically connected;The PWM signal output end of control circuit board and the signal input end of processing circuit, second regulating circuit are electrically connected, and the signal output end of processing circuit and the signal input end of first regulating circuit are electrically connected, and the signal output end of second regulating circuit and the signal input end of output circuit are electrically connected, and the power supply output end of output circuit, first regulating circuit and the power supply input end of electric proportional valve drive coil are electrically connected, and the signal output end of first regulating circuit and the signal input end of output circuit are electrically connected.

2. The control circuit for a quick exhaust solenoid proportional valve coil residual current according to claim 1, characterized in that, The processing circuit includes electrically connected driving chip, diode, resistance, capacitor, the first resistance one end and the HIN port, LIN port of driving chip are connected, the VCC port of driving chip and the first capacitor one end, the second capacitor one end, the positive electrode of diode are connected, the negative electrode of diode and the second resistance one end are connected, the second resistance other end and the third capacitor one end, the VB port of driving chip are connected, the VS port of driving chip and the third capacitor other end are connected, the first capacitor other end and the second capacitor other end, the COM port of driving chip are connected.

3. The control circuit for a quick exhaust solenoid proportional valve coil residual current according to claim 1, characterized in that, The first regulating circuit includes electrically connected diode and resistance, driving tube, capacitor, the first diode negative electrode and the first resistance one end are connected, the second diode negative electrode and the second resistance one end are connected, the first diode positive electrode and the third resistance one end, the first driving tube gate are connected, the first driving tube drain and the first capacitor one end, the second capacitor one end are connected, the third resistance other end and the first driving tube source, the second driving tube drain are connected, the first diode positive electrode and the second resistance other end, the fourth resistance one end, the second driving tube source are connected, the fourth resistance other end and the second driving tube source, the first capacitor other end, the second capacitor other end are connected.

4. The control circuit for a quick exhaust solenoid proportional valve coil residual current according to claim 1, characterized in that, The second regulating circuit includes electrically connected resistance and triode, capacitor, the first resistance one end and the second resistance one end, the first triode base are connected, the first triode collector and the third resistance one end, the second triode base are connected, the second triode collector and the fourth resistance one end, the third triode base, the fourth triode base are connected, the third diode emitter and the fourth triode emitter are connected, the capacitor one end and the third resistance one end, the fourth resistance one end, the third triode collector are connected, the capacitor other end and the second resistance other end, the first triode emitter, the second triode emitter, the fourth triode emitter are connected.

5. The control circuit for a quick exhaust electro-proportional valve coil residual current according to claim 1, characterized in that, The output circuit includes electrically connected diode and driving tube, resistance, the first resistance one end and the second resistance one end, the driving tube gate are connected, the second resistance other end and the driving tube source are connected, and the driving tube drain and the diode positive electrode are connected.

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