Solenoid valve drive circuit, method of operating same, and valve assembly including same

Abstract

The invention relates to an electromagnetic valve driving circuit which comprises a power source, a single-chip microcomputer, a driving chip and a feedback loop, and the power source is used for supplying power to the single-chip microcomputer and the driving chip; the single-chip microcomputer is used for outputting a corresponding PWM signal to the driving chip according to a user instruction. The driving chip is used for outputting a target control current Itarget to the electromagnetic valve according to a PWM signal received from the single chip microcomputer so as to control the opening and closing of the electromagnetic valve; the feedback loop is used for obtaining the current working current value of the electromagnetic valve and feeding back the current working current value to the single chip microcomputer, and the single chip microcomputer is configured to adjust the duty ratio of a PWM signal output by the single chip microcomputer in real time according to the working current value provided by the feedback loop so as to control the current output precision of the driving chip. The invention also relates to an operation method of the electromagnetic valve driving circuit and a valve assembly comprising the electromagnetic valve driving circuit.

Description

Technical Field

[0001] The present invention relates to the technical field of solenoid valves, and more specifically, to a solenoid valve drive circuit and an operating method thereof, and a valve assembly including the solenoid valve drive circuit. Background Art

[0002] Solenoid valves play an important role in many modern industries. For example, with the rapid development of modern vehicle electronic control technology, solenoid valves are increasingly used in vehicles. For example, in many vehicle transmissions, solenoid valves are required to achieve gear shifting.

[0003] The working principle of the solenoid valve is based on a precise combination of electromagnetic induction and current control. It requires the use of a solenoid valve drive circuit to adjust the current output to the solenoid valve. The current acts on the coil inside the solenoid valve based on electromagnetic induction, thereby generating an electromagnetic field, thereby manipulating the opening state of the solenoid valve.

[0004] A common solenoid valve driving method is to control the output current of the chip by outputting a pulse width modulation (PWM) signal to the driver chip through the SPI communication line. However, the output current accuracy of this driving method is not high, and the driving process is greatly affected by the ambient temperature. Summary of the invention

[0005] In view of this, according to a first aspect of the present invention, a solenoid valve driving circuit is proposed, the driving circuit comprising a power supply, a single chip microcomputer, a driving chip and a feedback loop.

[0006] The power supply is used to supply power to the single chip microcomputer and the driving chip;

[0007] The single chip microcomputer is used to output a corresponding PWM signal to the driving chip according to a user instruction;

[0008] The driving chip is used to output a target control current I_target to the solenoid valve according to the PWM signal received from the single chip microcomputer to control the opening and closing of the solenoid valve;

[0009] The feedback loop is used to obtain the current working current value of the solenoid valve and feed it back to the single chip microcomputer.

[0010] The single chip microcomputer is configured to adjust the duty cycle of the PWM signal outputted by it in real time according to the working current value provided by the feedback loop, so as to control the current output accuracy of the driving chip.

[0011] Advantageously, the single chip microcomputer is further configured as:

[0012] Averaging a plurality of operating current values ​​received from the feedback loop within one PWM signal cycle, and using the averaged result as the actual current I_actual of the solenoid valve;

[0013] calculating a current difference ΔI between the actual current I_actual and the target control current I_target; and

[0014] The duty cycle of the PWM signal output by the single chip microcomputer is adjusted based on the current difference ΔI.

[0015] Advantageously, the single chip microcomputer is further configured as:

[0016] - determining an intermediate adjustment variable ΔH for adjusting the duty cycle of the PWM signal based on the current difference ΔI;

[0017] Reading the operating voltage Vbat of the power supply;

[0018] The duty cycle variation ΔDUTY to be adjusted is calculated based on the intermediate adjustment variable ΔH and the working voltage Vbat of the power supply:

[0019] ΔDUTY=(100*d*10)*ΔH / Vbat,

[0020] Wherein d is a predefined adjustment parameter stored in a register in the single chip microcomputer;

[0021] Obtaining the actual duty cycle value DUTY_current of the current PWM signal output by the single chip microcomputer;

[0022] Calculating a new duty cycle value DUTY_new based on the duty cycle change amount ΔDUTY and the actual duty cycle value DUTY_current;

[0023] Adjusting the duty cycle of the PWM signal output by the single chip microcomputer to the new duty cycle value DUTY_new; and

[0024] The regulated PWM signal is output to the driving chip.

[0025] Advantageously, the single chip microcomputer is further configured to determine whether the new duty cycle value DUTY_new exceeds an upper limit value.

[0026] The duty cycle of the PWM signal is adjusted to the new duty cycle value DUTY_new only when the new duty cycle value DUTY_new does not exceed the upper limit value.

[0027] Advantageously, the single chip microcomputer is further configured to send an error signal to an upper layer controller when the new duty cycle value DUTY_new exceeds an upper limit value, and re-execute the process of determining the duty cycle variation ΔDUTY.

[0028] Advantageously, the new duty cycle value DUTY_new is determined using the following formula: DUTY_new=DUTY_current+(DUTY_current+ΔDUTY) / (100*e*10), wherein e is a predefined adjustment parameter.

[0029] Advantageously, the intermediate adjustment variable ΔH is a hexadecimal value used to determine the duty cycle of the PWM signal sent by the single chip microcomputer.

[0030] Advantageously, the intermediate adjustment variable ΔH is determined using the following formula:

[0031] ΔH=ΔH0+[((a*ΔI)+(b*ΔI0)) / c],

[0032] Wherein, a, b, c are preset adjustment parameters, ΔH0 is a preset initial adjustment change, and ΔI0 is a preset initial current difference.

[0033] According to a second aspect of the present invention, there is further provided a valve assembly, the valve assembly comprising:

[0034] Solenoid valve,

[0035] Solenoid valve driving circuit as described above.

[0036] According to a third aspect of the present invention, there is also provided an operating method of the solenoid valve drive circuit as described above, the operating method comprising the following steps:

[0037] Outputting corresponding PWM signals to the driving chip based on user instructions by means of the single chip microcomputer;

[0038] Outputting a target control current I_target to the solenoid valve based on a PWM signal output by the single chip microcomputer by means of the driving chip to control the opening and closing of the solenoid valve;

[0039] Acquiring the current working current value of the solenoid valve by means of the feedback loop and feeding it back to the single chip microcomputer; and

[0040] The single chip microcomputer is used to adjust the duty cycle of the PWM signal outputted by the single chip microcomputer in real time according to the working current value provided by the feedback loop, so as to control the current output accuracy of the driving chip.

[0041] The solenoid valve drive circuit with adjustable duty cycle according to the present invention has broad application prospects in improving system performance, reducing resource consumption, and improving application flexibility. Specifically, the drive circuit can establish an accurate current control channel between the solenoid valve drive chip and the solenoid valve by adjusting the duty cycle of the PWM signal in real time, thereby realizing accurate control of the solenoid valve. This drive control method is very flexible, and can adjust the working state of the solenoid valve in real time as needed, and can achieve more accurate current output by continuously sending the calibrated duty cycle, and can adapt to different working requirements of the solenoid valve. In addition, this drive control method can reduce the heat generated by the solenoid valve, thereby extending the service life of the solenoid valve and reducing the circuit maintenance cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] By incorporating the accompanying drawings and Figure 1 With reference to the specific embodiments used to illustrate certain principles of the present invention, other features and advantages of the method of the present invention will become clear or be described in more detail.

[0043] Figure 1 A schematic structural diagram of a solenoid valve driving circuit according to an exemplary embodiment of the present invention is shown.

[0044] Figure 2 A flowchart showing an operating method of a solenoid valve driving circuit according to an exemplary embodiment of the present invention DETAILED DESCRIPTION

[0045] The solenoid valve drive circuit according to the present invention will be described below with reference to the accompanying drawings and by way of example. In the following description, many specific details are set forth in order to enable a person skilled in the art to more fully understand the present invention. However, it is obvious to a person skilled in the art that the present invention may be implemented without some of these specific details. Instead, it is contemplated that the present invention may be implemented with any combination of the following features and elements, regardless of whether they relate to different embodiments. Therefore, the following various aspects, features, embodiments and advantages are for illustrative purposes only and should not be regarded as elements or limitations of the claims.

[0046] The applicant has found that the conventional PWM drive circuit uses a single-chip microcomputer to generate a PWM signal to adjust the current output by the solenoid valve driver chip to the solenoid valve. The PWM signal contains a high level (usually a power supply voltage) and a low level (usually a ground). The duty cycle of the PWM signal represents the proportion of time occupied by the high level in a cycle. By adjusting the duration of the high level (the percentage of the duty cycle), the current output by the solenoid valve drive circuit can be controlled. A higher duty cycle will cause the solenoid valve driver chip to output a larger current, while a lower duty cycle will cause the output current to decrease.

[0047] However, the current control accuracy of the above PWM driving method is not high, and it is greatly affected by the ambient temperature during the driving process of the solenoid valve. To this end, the present invention proposes a new solenoid valve driving circuit, which adjusts the control current output to the solenoid valve by changing the duty cycle of the PWM signal, thereby realizing the driving control of the solenoid valve. At the same time, the driving circuit can detect the working current of the solenoid valve in real time with the help of a feedback loop, and feed it back to the single-chip microcomputer, and the single-chip microcomputer can make real-time adjustments to the driving control of the solenoid valve according to the working current fed back.

[0048] Figure 1 FIG. 2 shows a schematic diagram of a solenoid valve driving circuit according to an exemplary embodiment of the present invention. Figure 1 As shown in , the driving circuit may generally include a power supply, a single chip microcomputer, a driving chip and a feedback loop. The power supply may be a direct current source, which is used to supply power to the single chip microcomputer and the driving chip.

[0049] When receiving a user command to open / close the solenoid valve, the MCU can output a corresponding PWM signal to the driver chip. According to the PWM signal, the driver chip can output a target control current I_target to the solenoid valve to control the opening and closing of the solenoid valve. Among them, the duty cycle of the PWM signal output by the MCU is pre-set, and the size of the duty cycle directly determines the size and frequency of the output current of the driver chip.

[0050] In order to achieve closed-loop control of current, the feedback loop can be used to obtain the current working current of the solenoid valve in real time and feed it back to the microcontroller. Based on the fed-back working current, the microcontroller can analyze and calculate it, and adjust the duty cycle of the PWM signal it outputs in real time according to the calculation results, ultimately improving the current control accuracy of the driver chip.

[0051] The above duty cycle adjustment process can be found in Figure 2 , which shows a flow chart of an operation method of a solenoid valve driving circuit according to an exemplary embodiment of the present invention. Most of the analysis and calculation processes in the operation method can be executed in a single chip microcomputer.

[0052] like Figure 2 As shown in FIG. 1 , first, in step S101 , a plurality of operating current values ​​received from the feedback loop within one PWM signal cycle are averaged, so that the averaged result is used as the actual current I_actual of the solenoid valve.

[0053] Then, in step S102, the current difference ΔI between the actual current I_actual and the target control current I_target is calculated:

[0054] ΔI=I_actual-I_target.

[0055] Based on the difference ΔI, the duty cycle of the PWM signal output by the microcontroller can be adjusted accordingly.

[0056] Specifically, in step S103 , an intermediate adjustment variable ΔH may be calculated based on the current difference ΔI. The intermediate adjustment variable ΔH may be a hexadecimal value stored in the microcontroller and used to determine the duty cycle of the PWM signal sent by the microcontroller.

[0057] As an example, the intermediate adjustment variable ΔH may be determined based on the following formula.

[0058] ΔH=ΔH0+[((a*ΔI)+(b*ΔI0)) / c],

[0059] Wherein, a, b, c are preset adjustment parameters, ΔH0 is the preset initial adjustment change, and ΔI0 is the preset initial current difference. As an example of hexadecimal values, a=2141, b=-2059, and scaling factor c=2048 can be set. Wherein, the initial value can be set to ΔH0=0, ΔI0=0. These parameters and initial values ​​can be preset by the microcontroller based on the circuit parameters and stored in its registers.

[0060] Synchronously with or subsequently to step S103, in step S104, the working voltage Vbat of the power supply may be read, and based on the working voltage Vbat and the intermediate adjustment variable ΔH calculated above, the duty cycle change ΔDUTY to be adjusted may be further calculated in step S105. For example, ΔDUTY may be calculated as:

[0061] ΔDUTY=(100*d*10)*ΔH / Vbat,

[0062] Wherein, d is a predefined adjustment parameter stored in a register in the microcontroller;

[0063] Subsequently, in step S106, the actual duty cycle value DUTY_current of the current PWM signal output by the single chip microcomputer may be obtained, and based on the actual duty cycle value DUTY_current and the duty cycle variation ΔDUTY calculated above, a new duty cycle value DUTY_new may be further estimated in step S107.

[0064] As an example, the new duty cycle value DUTY_new may be obtained by simply adding the actual duty cycle DUTY_current and the change ΔDUTY. As another example, the new duty cycle value DUTY_new may be determined by the following formula: DUTY_new=DUTY_current+(DUTY_current+ΔDUTY) / (100*e*10), where e is a predefined adjustment parameter.

[0065] After determining the new duty cycle value DUTY_new, it can be further determined in step S108 whether it exceeds the upper limit value (e.g., 100%). If not, the duty cycle of the PWM signal output by the single-chip microcomputer is adjusted to the new duty cycle value DUTY_new in step S109, and the adjusted PWM signal is output to the driver chip in step S110. Otherwise, the single-chip microcomputer sends an error signal to the upper-level controller and re-executes the process of determining the duty cycle change ΔDUTY.

[0066] An exemplary embodiment of the present invention further provides a valve assembly, which includes a solenoid valve and the solenoid valve driving circuit described above.

[0067] The solenoid valve drive circuit with adjustable duty cycle according to the present invention has broad application prospects in improving system performance, reducing resource consumption, and improving application flexibility. Specifically, the drive circuit can establish an accurate current control channel between the solenoid valve drive chip and the solenoid valve by adjusting the duty cycle of the PWM signal in real time, thereby realizing accurate control of the solenoid valve. This drive control method is very flexible, and can adjust the working state of the solenoid valve in real time as needed, and can achieve more accurate current output by continuously sending the calibrated duty cycle, and can adapt to different working requirements of the solenoid valve. In addition, this drive control method can reduce the heat generated by the solenoid valve, thereby extending the service life of the solenoid valve and reducing the circuit maintenance cost.

[0068] It will be appreciated by those skilled in the art that the various steps of the method according to the present invention can be performed in a given order. However, it should be noted that different orders are also possible. The method may include other method steps that are not listed. In addition, one or more of the method steps may be performed once or repeatedly. In addition, two or more of the method steps may be performed simultaneously or in a temporally overlapping manner. In addition, in the present invention, terms such as "comprising" and "including" indicate that in addition to having steps that are directly and clearly stated in the specification and claims, the technical solution of the present application does not exclude the situation of having other steps that are not directly or clearly stated.

[0069] Although the present invention has been disclosed as above with preferred embodiments, the present invention is not limited thereto. Any changes and modifications made by any person skilled in the art without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention, and therefore the protection scope of the present invention should be subject to the scope defined by the claims.

Claims

1. A solenoid valve drive circuit, characterized in that: The driving circuit includes a power supply, a single chip microcomputer, a driving chip and a feedback loop. The power supply is used to supply power to the single chip microcomputer and the driving chip; The single chip microcomputer is used to output a corresponding PWM signal to the driving chip according to a user instruction; The driving chip is used to output a target control current I_target to the solenoid valve according to the PWM signal received from the single chip microcomputer to control the opening and closing of the solenoid valve; The feedback loop is used to obtain the current working current value of the solenoid valve and feed it back to the single-chip microcomputer, wherein the single-chip microcomputer is configured to adjust the duty cycle of the PWM signal it outputs in real time according to the working current value provided by the feedback loop to control the current output accuracy of the driver chip.

2. The solenoid valve driving circuit according to claim 1, characterized in that: The single chip microcomputer is further configured as: Averaging a plurality of operating current values ​​received from the feedback loop within a PWM signal cycle, and using the averaged result as the actual current I_actual of the solenoid valve; Calculating a current difference ΔI between the actual current I_actual and the target control current I_target; as well as The duty cycle of the PWM signal output by the single chip microcomputer is adjusted based on the current difference ΔI.

3. The solenoid valve driving circuit according to claim 2, characterized in that: The single chip microcomputer is further configured as: - determining an intermediate adjustment variable ΔH for adjusting the duty cycle of the PWM signal based on the current difference ΔI; Reading the operating voltage Vbat of the power supply; The duty cycle variation ΔDUTY to be adjusted is calculated based on the intermediate adjustment variable ΔH and the working voltage Vbat of the power supply: ΔDUTY=(100*d*10)*ΔH / Vbat, Wherein d is a predefined adjustment parameter stored in a register in the single chip microcomputer; Obtaining the actual duty cycle value DUTY_current of the current PWM signal output by the single chip microcomputer; Calculating a new duty cycle value DUTY_new based on the duty cycle change amount ΔDUTY and the actual duty cycle value DUTY_current; Adjusting the duty cycle of the PWM signal output by the single chip microcomputer to the new duty cycle value DUTY_new; and The regulated PWM signal is output to the driving chip.

4. The solenoid valve driving circuit according to claim 3, characterized in that: The single chip microcomputer is further configured to determine whether the new duty cycle value DUTY_new exceeds an upper limit value, The duty cycle of the PWM signal is adjusted to the new duty cycle value DUTY_new only when the new duty cycle value DUTY_new does not exceed the upper limit value.

5. The solenoid valve driving circuit according to claim 4, characterized in that: The single chip microcomputer is further configured to send an error signal to the upper layer controller when the new duty cycle value DUTY_new exceeds the upper limit value, and re-execute the process of determining the duty cycle change amount ΔDUTY.

6. The solenoid valve driving circuit according to any one of claims 3 to 5, characterized in that: The new duty cycle value DUTY_new is determined by using the following formula: DUTY_new=DUTY_current+(DUTY_current+ΔDUTY) / (100*e*10), where e is a predefined adjustment parameter.

7. The solenoid valve driving circuit according to any one of claims 3 to 5, characterized in that: The intermediate adjustment variable ΔH is a hexadecimal value used to determine the duty cycle of the PWM signal sent by the single chip microcomputer.

8. The solenoid valve driving circuit according to claim 7, characterized in that: The intermediate adjustment variable ΔH is determined using the following formula: ΔH=ΔH0+[((a*ΔI)+(b*ΔI0)) / c], Wherein, a, b, c are preset adjustment parameters, ΔH0 is a preset initial adjustment change, and ΔI0 is a preset initial current difference.

9. A valve assembly, characterized in that: The valve assembly includes: Solenoid valve, and A solenoid valve drive circuit according to any one of claims 1 to 8.

10. An operating method of a solenoid valve driving circuit according to any one of claims 1 to 8, characterized in that: The operation method includes the following steps: Outputting corresponding PWM signals to the driving chip based on user instructions by means of the single chip microcomputer; Outputting a target control current I_target to the solenoid valve based on a PWM signal output by the single chip microcomputer by means of the driving chip to control the opening and closing of the solenoid valve; Acquiring the current working current value of the solenoid valve by means of the feedback loop and feeding it back to the single chip microcomputer; and The single chip microcomputer is used to adjust the duty cycle of the PWM signal outputted by the single chip microcomputer in real time according to the working current value provided by the feedback loop, so as to control the current output accuracy of the driving chip.

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