Estimation method, acquisition link monitoring method, and readable storage medium

Abstract

The application provides an estimation method, a collection link monitoring method and a readable storage medium. The estimation method comprises the following steps: calculating a valve core temperature estimation value of a solenoid valve based on a first sampling value of a solenoid valve current and a second sampling value of an oil temperature; calculating a valve core resistance estimation value of the solenoid valve based on the valve core temperature estimation value; and calculating an estimation value of the solenoid valve current based on the valve core resistance estimation value. In this way, the solenoid valve current is estimated based on the oil temperature, and the estimation value is used to determine whether the collection link fails. Meanwhile, the collection link monitoring method constructed based on the estimation method can be realized without adding additional hardware, thereby solving the problem that there is no collection link monitoring method with monitoring effect realized without adding hardware in the prior art.

Description

Technical Field

[0001] This invention relates to the field of solenoid valve control technology, and in particular to an estimation method, a data acquisition link monitoring method, and a readable storage medium. Background Technology

[0002] Solenoid valves, as common actuators, play a crucial role in automotive powertrain systems, suspension systems, and thermal management systems, and have very high requirements for functional safety levels. Currently, the current closed-loop control of solenoid valves is mainly achieved through PWM modulation. The target current is given by a command issued by the application system, and the actual current output of the solenoid valve is mostly calculated by collecting the voltage drop across the shunt terminals of the solenoid valve control loop. Figure 1 The diagram shows a schematic of a closed-loop control system for a solenoid valve current. The controller compares the actual current sampled with the target current to monitor whether unexpected large currents or unexpected insufficient currents occur in the solenoid valve control.

[0003] Figure 2 The diagram illustrates the current monitoring principle of a solenoid valve control loop based on target current and actual sampled current. Since both current closed-loop control and current monitoring are based on feedback current, if the current acquisition link in the control system fails—for example, if the Shunt resistor experiences impedance drift or the operational amplifier in the current sampling circuit fails—this failure cannot be detected and corrected in time. This results in a significant deviation in the actual output current of the solenoid valve, posing a substantial safety hazard to the control system. Furthermore, a single diagnostic path cannot meet the requirements of high-functional safety applications. Some control systems, in order to improve the reliability of current diagnostics, employ an additional current sampling path. Cross-checking the dual current sampling values ​​enhances the diagnostic functional safety level, but this significantly increases the system's application cost and limits the feasibility of such redundant monitoring.

[0004] In summary, the traditional method for controlling and monitoring the current of solenoid valves has the following shortcomings:

[0005] 1. The current monitoring path is singular and has low security. It uses Shunt resistors combined with voltage operational amplifier circuits or current sensor sampling methods to collect current. Current monitoring relies on feedback current; if the feedback current fails, the current acquisition circuit cannot be monitored for failure. When electronic components fail, the system cannot obtain the corresponding failure information and correct it in a timely manner, compromising product safety. Furthermore, the singular monitoring path cannot meet the application scenarios with higher functional safety requirements.

[0006] 2. The diagnostic coverage is low. It uses a single sampling current and target current for comparison, which cannot cover failures of the solenoid valve body, wiring harness, connectors, etc. If the impedance of the solenoid valve body shifts significantly, or if the solenoid valve control circuit introduces a large impedance, such as a bypass short circuit in the solenoid valve or a large impedance introduced by the solenoid valve or controller connector, these failures cannot be diagnosed through this diagnostic path.

[0007] 3. Redundancy verification is costly. Using an additional current sampling channel for redundancy verification increases the application cost of the system and cannot meet the requirements of low cost.

[0008] Therefore, it is necessary to add an independent monitoring path that does not rely on the controller's current sampling, in order to achieve current monitoring with higher functional safety requirements, based on the existing monitoring of control current and feedback current.

[0009] In other words, there is a lack of current technology that can achieve monitoring effects without adding hardware to the data acquisition link. Summary of the Invention

[0010] The purpose of this invention is to provide an estimation method, a data acquisition link monitoring method, and a readable storage medium to solve the problem in the prior art of lacking a data acquisition link monitoring method that can achieve monitoring effects without adding hardware.

[0011] To address the aforementioned technical problems, this invention provides an estimation method applied to a solenoid valve, the solenoid valve including a valve core, the estimation method comprising: calculating an estimated value of the valve core temperature of the solenoid valve based on a first sampled value and a second sampled value; calculating an estimated value of the valve core resistance of the solenoid valve based on the estimated value of the valve core temperature; and calculating an estimated value of the solenoid valve current based on the estimated value of the valve core resistance.

[0012] Optionally, the step of calculating the estimated valve core temperature of the solenoid valve based on the first sampled value and the second sampled value includes: acquiring the temperature rise data of the valve core of the solenoid valve and acquiring the temperature difference-time curve of the valve core; fitting the temperature difference-time curve with a first-order filtering model and calibrating the temperature rise time coefficient and temperature rise time constant; wherein the temperature rise time coefficient is the time when the first-order filtering model reaches its 63% maximum value, and the temperature rise time constant is the time when the first-order filtering model reaches its maximum value; calculating the temperature difference of the valve core based on the temperature rise time coefficient and the temperature rise time constant using discrete integration; wherein the calculation model is the first-order filtering model; and adding the second sampled value to the temperature difference of the valve core to obtain the estimated valve core temperature.

[0013] Optionally, the step of calculating the temperature difference of the valve core based on the temperature rise time coefficient and the temperature rise time constant using discrete integration includes: obtaining the self-heating coefficient of the valve core, wherein the self-heating coefficient is obtained by dividing the maximum temperature difference between the valve core and the oil temperature under a preset operating condition by the heating power of the valve core under the preset operating condition; the preset operating condition is the condition when the valve core and the working oil are in full heat exchange; and calculating the temperature difference of the valve core using discrete integration based on the temperature rise time coefficient, the temperature rise time constant, the resistance reference value of the valve core, the resistance temperature coefficient of the valve core, the self-heating coefficient, and the first sampled value.

[0014] Optionally, the step of calculating the valve core resistance estimate of the solenoid valve based on the valve core temperature estimate includes: calculating the valve core resistance estimate of the solenoid valve using a linear model based on the valve core resistance reference value, the valve core resistance temperature coefficient, and the valve core temperature estimate.

[0015] Optionally, the step of calculating the estimated value of the solenoid valve current based on the estimated value of the valve core resistance includes: setting a current calculation formula based on the operating mode of the solenoid valve; and substituting the estimated value of the valve core resistance into the current calculation formula to calculate the estimated value of the solenoid valve current.

[0016] Optionally, the solenoid valve operates in PWM mode, and the current calculation formula is based on the high-side voltage, duty cycle, equivalent charging resistance of the control loop, equivalent discharging resistance of the control loop, and voltage drop across the freewheeling diode during discharge; wherein, the estimated value of the valve core resistance is used in the calculation of the equivalent charging resistance and the equivalent discharging resistance.

[0017] Optionally, the charging equivalent resistance is the sum of the estimated value of the valve core resistance, the current sampling resistor, the connection resistance in the control circuit, and the equivalent resistance of the switching transistor; the discharging equivalent resistance is the sum of the estimated value of the valve core resistance, the current sampling resistor, the connection resistance in the control circuit, and the equivalent resistance of the freewheeling diode.

[0018] To address the aforementioned technical problems, the present invention also provides a data acquisition link monitoring method, the data acquisition link monitoring method comprising: calculating an estimated value of the solenoid valve current based on a first sampled value of the solenoid valve current and a second sampled value of the oil temperature; and determining whether the data acquisition link has failed based on the difference between the estimated value and the first sampled value.

[0019] Optionally, the step of determining whether the acquisition link has failed based on the difference between the estimated value and the first sampled value includes:

[0020] Calculate the upper threshold and the lower threshold, wherein the upper threshold includes a dynamic upper threshold and a static upper threshold, the static upper threshold is obtained by looking up a table based on the first sampled value, and the dynamic upper threshold is obtained by multiplying the first sampled value by the upper threshold parameter; the lower threshold includes a dynamic lower threshold and a static lower threshold, the static lower threshold is obtained by looking up a table based on the first sampled value, and the dynamic lower threshold is obtained by multiplying the first sampled value by the lower threshold parameter.

[0021] Furthermore, if the difference is greater than the upper threshold, the acquisition link is determined to be faulty, and an overcurrent alarm signal is output; if the difference is less than the lower threshold, the acquisition link is determined to be faulty, and an undercurrent alarm signal is output; otherwise, the acquisition link is determined to be valid.

[0022] Optionally, the step of calculating the estimated value of the solenoid valve current based on the first sampled value of the solenoid valve current and the second sampled value of the oil temperature includes: calculating the estimated value of the valve core temperature of the solenoid valve based on the first sampled value and the second sampled value; calculating the estimated value of the valve core resistance of the solenoid valve based on the estimated value of the valve core temperature; and calculating the estimated value of the solenoid valve current based on the estimated value of the valve core resistance.

[0023] To address the aforementioned technical problems, the present invention also provides a readable storage medium storing a program, which, when executed, performs the aforementioned estimation method or data acquisition link monitoring method.

[0024] Compared with existing technologies, the present invention provides an estimation method, a data acquisition link monitoring method, and a readable storage medium. The estimation method includes: calculating an estimated value of the solenoid valve core temperature based on a first sampled value of the solenoid valve current and a second sampled value of the oil temperature; calculating an estimated value of the solenoid valve core resistance based on the estimated value of the core temperature; and calculating an estimated value of the solenoid valve current based on the estimated value of the core resistance. This configuration estimates the solenoid valve current based on the oil temperature and uses the estimated value to determine if a data acquisition link failure has occurred. Furthermore, the data acquisition link monitoring method built based on this estimation method can be implemented without adding additional hardware, solving the problem in existing technologies of lacking a data acquisition link monitoring method that can achieve monitoring effects without adding hardware. Attached Figure Description

[0025] Those skilled in the art will understand that the accompanying drawings are provided to better understand the invention and do not constitute any limitation on the scope of the invention. Wherein:

[0026] Figure 1 This is a schematic diagram of a closed-loop control system for electromagnetic valve current.

[0027] Figure 2This is a schematic diagram illustrating the circuit current monitoring principle of a solenoid valve.

[0028] Figure 3 This is a flowchart illustrating a data acquisition link monitoring method according to an embodiment of the present invention;

[0029] Figure 4 This is a temperature difference-time curve of the valve core according to an embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram of a data acquisition link monitoring method according to an embodiment of the present invention. Detailed Implementation

[0031] To make the objectives, advantages, and features of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to facilitate and clarify the explanation of the embodiments of this invention. Furthermore, the structures shown in the drawings are often part of the actual structures. In particular, different figures may emphasize different aspects and may sometimes use different scales.

[0032] As used in this invention, the singular forms “a,” “an,” and “the” include plural objects; the term “or” is generally used to mean “and / or”; the term “a number” is generally used to mean “at least one”; and the term “at least two” is generally used to mean “two or more”. Furthermore, the terms “first,” “second,” and “third” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as “first,” “second,” or “third” may explicitly or implicitly include one or at least two of that feature. “One end” and “the other end,” as well as “proximal end” and “distal end,” generally refer to two corresponding parts, including not only endpoints. The terms “installed,” “connected,” and “joined” should be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral part; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or a connection within two elements or an interaction between two elements. Furthermore, as used in this invention, the phrase "one element is disposed on another element" generally only indicates that there is a connection, coupling, cooperation, or transmission relationship between the two elements, and the connection, coupling, cooperation, or transmission between the two elements can be direct or indirect through an intermediate element. It should not be construed as indicating or implying a spatial positional relationship between the two elements, i.e., one element can be located arbitrarily inside, outside, above, below, or to one side of the other element, unless otherwise explicitly stated. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0033] The core idea of ​​this invention is to provide an estimation method, a data acquisition link monitoring method, and a readable storage medium to solve the problem in the prior art of lacking a data acquisition link monitoring method that can achieve monitoring effects without adding hardware.

[0034] The following description refers to the accompanying drawings.

[0035] This embodiment provides an estimation method, which is used to participate in the construction of the data acquisition link monitoring method. For ease of understanding, the overall content of the data acquisition link monitoring method will be introduced below.

[0036] Please refer to Figure 3 This embodiment provides a data acquisition link monitoring method applied to a solenoid valve, the solenoid valve including a valve core, the data acquisition link monitoring method including: S10, calculating an estimated value of the solenoid valve current based on a first sampled value of the solenoid valve current and a second sampled value of the oil temperature; and S20, determining whether the data acquisition link has failed based on the difference between the estimated value and the first sampled value.

[0037] When sampling physical quantities, the directly obtained signal may not be the physical quantity itself. For example, the solenoid valve current is 200mA, but the corresponding sampling result may be 50mV. However, in this application, the first and second sampled values ​​should be understood as physical quantities corresponding to the actual physical quantities obtained after conversion of the sampled signals. In the absence of any faults and without considering all errors, the first sampled value should be understood as equal to the solenoid valve current; the second sampled value should be understood as equal to the oil temperature.

[0038] In general understanding, temperature is prone to significant errors during both data acquisition and calculation. Current values ​​calculated based on temperature cannot be directly used in automatic control. This embodiment proposes that the calculated current value can be used to determine the reasonable current range, thereby expanding its application scope. In other words, oil temperature provides sufficient information to determine whether the sampled current value is within a reasonable range. If it exceeds this range, it can be assumed that a fault has occurred in a link of the data acquisition chain, contributing to improved overall system safety.

[0039] Please continue to refer to this. Figure 3To improve the accuracy of the calculation results, step S10, the step of calculating the estimated value of the solenoid valve current based on the first sampled value of the solenoid valve current and the second sampled value of the oil temperature, includes: S11, calculating the estimated value of the valve core temperature of the solenoid valve based on the first sampled value and the second sampled value; S12, calculating the estimated value of the valve core resistance of the solenoid valve based on the estimated value of the valve core temperature; and S13, calculating the estimated value of the solenoid valve current based on the estimated value of the valve core resistance. In fact, step S10 is the estimation method. The technical details of the estimation method can be understood by referring to the relevant description in the data acquisition link monitoring method.

[0040] It is understandable that many electrical parameters remain unchanged after leaving the factory during current calculation; the key parameter to calculate is the valve core resistance of the solenoid valve. In this embodiment, the valve core temperature is estimated based on the oil temperature, and then the valve core resistance is calculated based on the valve core temperature.

[0041] Specifically, step S11, the step of calculating the estimated valve core temperature of the solenoid valve based on the first sampled value and the second sampled value, includes: S111, acquiring the temperature rise data of the valve core of the solenoid valve, and acquiring the temperature difference-time curve of the valve core; S112, fitting the temperature difference-time curve with a first-order filtering model, and calibrating the temperature rise time coefficient tau and the temperature rise time constant task; wherein, the temperature rise time coefficient tau is the time when the first-order filtering model reaches its 63% maximum value, and the temperature rise time constant task is the time when the first-order filtering model reaches its maximum value; S113, calculating the temperature difference of the valve core based on the temperature rise time coefficient and the temperature rise time constant using discrete integration; wherein, the calculation model is the first-order filtering model; and S114, the temperature difference T of the valve core... Delta Add the second sample value T Oil The estimated value T of the valve core temperature is obtained. Solenoid .

[0042] The resistance of the solenoid valve spool is related to its temperature. There are two main factors affecting the spool temperature: first, the ambient temperature. The valve body is immersed in the solenoid valve's working oil, and as the solenoid valve operates with current, the oil temperature rises. This oil temperature can be measured by an oil temperature sensor in the area where the solenoid valve's working oil is located. Second, the current flowing through the valve body. According to the thermal effect of current, when there is current in the valve body, the collision of free electrons causes the spool temperature to rise, which in turn affects the spool resistance. Therefore, the spool temperature will be higher than the ambient temperature. Once the ambient temperature and the current flowing through the spool stabilize, thermal equilibrium is achieved through sufficient heat exchange, and the spool temperature and ambient temperature will exhibit a fixed difference.

[0043] Steps S111 and S112 are steps that need to be completed in advance, namely, obtaining a suitable temperature difference-time curve under laboratory conditions and calibrating the relevant parameters. Temperature difference refers to the difference between the valve core temperature and the oil temperature. A typical temperature difference-time curve is shown below. Figure 4 As shown. The parameters tau and task can be found in [reference]. Figure 4 Please refer to the preceding text for clarification. In step S113, the calculation is performed according to the following formula:

[0044]

[0045] In the formula, T Delta (x) represents the temperature difference at time x, ΔT Max This indicates the maximum temperature difference, and also the temperature difference after the valve core and the environment have fully exchanged heat and reached thermal equilibrium.

[0046] Specifically, step S113, the step of calculating the temperature difference of the valve core based on the temperature rise time coefficient and the temperature rise time constant using discrete integration, includes: obtaining the self-heating coefficient f of the valve core. selPwrFact Wherein, the self-heating coefficient f selPwrFact Based on the maximum temperature difference ΔT between the valve core and the oil temperature under preset operating conditions Max Divide by the heat generation power P of the valve core under the preset operating conditions Actr,cond The preset operating condition is the condition when the valve core and the working oil are fully exchanging heat. Based on the temperature rise time coefficient, the temperature rise time constant, the reference value of the valve core resistance, the temperature coefficient of the valve core resistance, the self-heating coefficient, and the first sampled value, the temperature difference of the valve core is calculated by discrete integration.

[0047] In other words,

[0048]

[0049] Among them, I cond R represents the solenoid valve current under the preset operating conditions. Solenoid,cond This represents the valve core resistance under the preset operating conditions. The aforementioned R... Solenoid,cond The method for obtaining the valve core resistance value differs from the estimation methods used in other valve core resistance estimation methods in this application. For example, in PWM mode, the total circuit resistance is calculated based on the control circuit feedback duty cycle and voltage, and then R is calculated by subtracting the resistances of other components (such as the equivalent resistance of the switching transistor, connection resistance, etc.) from the total circuit resistance. Solenoid,cond I cond Then the first sampled value is used directly. selPwrFact The constant obtained through calibration is the inherent constant of the solenoid valve.

[0050] Based on the temperature rise time coefficient tau, the temperature rise time constant task, and the valve core resistance reference value R ref The temperature coefficient of resistance f of the valve core copper The self-heating coefficient f selPwrFact The formula for calculating the temperature difference of the valve core using discrete integration with the first sampled value I is as follows:

[0051]

[0052] In the formula, I(x) represents the first sampled value at time x, and T ref Indicates the resistance reference value R ref The corresponding temperature. T oil (x) represents the second sampled value. R ref Based on the characteristics of the solenoid valve, in a specific embodiment, R... ref The valve core resistance at 20℃, and the temperature coefficient of resistance f. copper The value is given in the solenoid valve manual and is generally 0.0039.

[0053] The calculation method for step S114 is as follows:

[0054] T Solenoid =T Oil +T Delta

[0055] Step S12, the step of calculating the valve core resistance estimate of the solenoid valve based on the valve core temperature estimate includes: calculating the valve core resistance estimate of the solenoid valve using a linear model based on the valve core resistance reference value, the valve core resistance temperature coefficient, and the valve core temperature estimate.

[0056] In one embodiment, the calculation is performed according to the following formula:

[0057] R Actr =R ref *[1+f copper *(T Solenoid -T ref )]

[0058] Among them, R Actr This is the resistance of the valve core at temperature T, which is also the estimated value of the valve core resistance.

[0059] The step of calculating the estimated value of the solenoid valve current based on the estimated value of the valve core resistance includes: setting a current calculation formula based on the operating mode of the solenoid valve; and substituting the estimated value of the valve core resistance into the current calculation formula to calculate the estimated value I of the solenoid valve current. est .

[0060] For example, the solenoid valve operates in PWM mode, and the current calculation formula is based on the high-side voltage U. HSD Duty cycle Rat fdbk The equivalent charging resistance R of the control circuit on The discharge equivalent resistance R of the control circuit off The voltage drop U across the freewheeling diode during discharge. Dde The calculation involves the estimated valve core resistance value being used in the calculation of the charging equivalent resistance and the discharging equivalent resistance. The formula is as follows:

[0061]

[0062] During charging, the current flows through the high side of the solenoid valve → valve core → shunt resistor → switching MOSFET → GND. The main resistors in this control circuit include the following components:

[0063] R Actr The resistance of the solenoid valve core is the main resistance in the control circuit. It is determined by the physical characteristics of the solenoid valve itself and can be calculated using a resistance-temperature model.

[0064] R shunt The current sampling resistor in the solenoid valve control circuit is determined by the component parameters during hardware design.

[0065] R wire_connection The connection resistance in the control circuit is mainly generated by the wiring harness and connectors, and needs to be calibrated or measured.

[0066] R Mos The equivalent resistance of a MOSFET can be calculated based on the MOSFET model selected by the solenoid valve control system and the temperature on the board.

[0067] Therefore, during charging, the resistance of the control loop can be expressed by the following formula:

[0068] R on =R Actr +R shunt +R wire_connection +R Mos

[0069] Similarly, during the discharge process, the current flows through the valve core → shunt resistor → freewheeling diode. The main resistance of this control circuit includes the following components:

[0070] R Actr The resistance of the solenoid valve core is the main resistance in the control circuit. It is determined by the physical characteristics of the solenoid valve itself and can be calculated using a resistance-temperature model.

[0071] R shuntThe current sampling resistor in the solenoid valve control circuit is determined by the component parameters during hardware design.

[0072] R wire_connection The connection resistance in the control circuit is mainly generated by the wiring harness and connectors, and needs to be calibrated or measured.

[0073] R Dde The equivalent resistance of the freewheeling diode can be calculated by combining the selected freewheeling diode model in the solenoid valve control system with the temperature on the board.

[0074] Therefore, during discharge, the resistance of the control circuit can be expressed by the following formula:

[0075] R off =R Actr +R shunt +R wire_connection +R Dde

[0076] That is, the charging equivalent resistance is the sum of the estimated value of the valve core resistance, the current sampling resistance, the connection resistance in the control circuit, and the equivalent resistance of the switching transistor; the discharging equivalent resistance is the sum of the estimated value of the valve core resistance, the current sampling resistance, the connection resistance in the control circuit, and the equivalent resistance of the freewheeling diode.

[0077] It is understood that, under other control modes or wiring methods, the current calculation formula and the relevant electrical parameters required for the calculation can also be adaptively set to obtain an estimated value of the solenoid valve current.

[0078] In this embodiment, the accuracy of the estimated value depends on the calibration of the resistance value of the charge / discharge control loop and the calibration of the resistance-temperature model. The key to calibrating the control loop lies in the vehicle's wiring harness R... wire_connection The key to calibrating the temperature-resistance model lies in calibrating the temperature rise time coefficient and the self-heating coefficient of the valve core. Other values ​​that need to be calibrated can be obtained from the solenoid valve manual or through calculation.

[0079] After estimating the actual current of the solenoid valve based on the resistance-temperature model, this embodiment can monitor the current and the current sampling based on the resistance-temperature model, as follows: Figure 5 As shown, the controller can compare the actual sampled current with the current estimated based on the resistance-temperature model to monitor whether the solenoid valve control experiences unexpected large current or unexpected insufficient current. This is used to cover failures in the current sampling loop, or failures in the solenoid valve body, wiring harness, connectors, etc., such as a large offset in the impedance of the solenoid valve body, or a large impedance introduced into the solenoid valve control loop (short circuit in the solenoid valve). Criteria for threshold calibration of this monitoring method are also given.

[0080] The current monitoring strategy based on feedback current and resistance-temperature model calculates the upper and lower current limits using the current sampling current. If the difference between the calculated current and the sampling current is lower than the lower current limit, a low current fault is reported; if the difference is higher than the upper current limit, a high current fault is reported. The calibration of the upper and lower current limits consists of two parts: dynamic threshold and static threshold.

[0081] The static threshold needs to be considered under all current conditions. The lower threshold is obtained by looking up the table based on the actual current, and the upper threshold is obtained by looking up the table based on the actual current.

[0082] Dynamic thresholds need to be considered under all current conditions. The upper and lower thresholds can be determined by multiplying the feedback current by a threshold coefficient, which can be obtained from the functional safety requirements defined by the system.

[0083] The above content can also be described as follows: Step S20, the step of determining whether the acquisition link has failed based on the difference between the estimated value and the first sampled value, includes:

[0084] S21, calculate the upper threshold and the lower threshold, wherein the upper threshold includes a dynamic upper threshold and a static upper threshold, the static upper threshold is obtained by looking up a table based on the first sampled value, and the dynamic upper threshold is obtained by multiplying the first sampled value by the upper threshold parameter; the lower threshold includes a dynamic lower threshold and a static lower threshold, the static lower threshold is obtained by looking up a table based on the first sampled value, and the dynamic lower threshold is obtained by multiplying the first sampled value by the lower threshold parameter.

[0085] And, S22, if the difference is greater than the upper limit of the threshold, the acquisition link is determined to be faulty and an overcurrent alarm signal is output; if the difference is less than the lower limit of the threshold, the acquisition link is determined to be faulty and an undercurrent alarm signal is output; otherwise, the acquisition link is determined to be valid.

[0086] This embodiment also provides a readable storage medium storing a program that, when executed, performs the aforementioned data acquisition link monitoring method. The readable storage medium provides the necessary hardware for the data acquisition link monitoring method, thus also solving the related technical problems.

[0087] The proposed method for estimating the control current of a solenoid valve based on a resistance-temperature model, and the implementation of redundant monitoring of the solenoid valve control current based on the estimated current results, offer the following improvements:

[0088] 1. To estimate the actual current of a solenoid valve without increasing costs, this invention uses a pure software solution compared to adding hardware components or external sensors. It establishes a resistance-temperature model of the solenoid valve to achieve online current estimation, which has the advantages of good real-time performance and high estimation accuracy. The software solution can reduce hardware costs.

[0089] 2. The functional safety level of the system is improved by implementing current redundancy verification based on the estimated current. By implementing the solenoid valve control current estimation algorithm based on the resistance-temperature model of this invention, and cross-verifying it with the actual collected feedback current, the failure of the current acquisition loop and the failure of the solenoid valve control loop can be monitored, which greatly improves the diagnostic coverage and functional safety level of the system.

[0090] 3. Flexible application in various scenarios: By implementing the electromagnetic valve control current estimation algorithm and monitoring mechanism based on the resistance-temperature model of this invention, it can be applied to various electromagnetic valve control scenarios, such as gearbox systems, suspension systems, thermal management systems, etc.

[0091] The present invention also has the following extensions:

[0092] 1. This technical solution uses a redundant electronic controller with a solenoid valve as the controlled object. This invention is still applicable to other control systems for any controlled object. This invention adopts a traditional discrete device (MCU+SBC+pre-driver chip) controller hardware architecture. For the use of integrated hardware solutions such as system-on-a-chip (SoC = MCU+SBC+pre-driver chip), it should still be regarded as a workaround for the technical solution proposed in this invention.

[0093] 2. The PI controller used in this technical solution for the PWM duty cycle output of the solenoid valve current control is still applicable to other control algorithms besides PI control.

[0094] 3. This technical solution revolves around the closed-loop control of the solenoid valve current. For PWM open-loop control, the resistance-temperature model proposed in this technical solution is still applicable.

[0095] 4. The redundancy verification mechanism proposed in this technical solution compares and monitors the estimated current and the acquired current. Other monitoring mechanisms, such as comparing and monitoring the estimated current and the target current, should still be considered as alternative designs to the technical solution proposed in this invention.

[0096] In summary, this embodiment provides an estimation method, a data acquisition link monitoring method, and a readable storage medium. The estimation method includes: calculating an estimated value of the solenoid valve core temperature based on a first sampled value of the solenoid valve current and a second sampled value of the oil temperature; calculating an estimated value of the solenoid valve core resistance based on the estimated core temperature; and calculating an estimated value of the solenoid valve current based on the estimated core resistance. This configuration estimates the solenoid valve current based on the oil temperature and uses the estimated value to determine if a data acquisition link failure has occurred. Furthermore, the data acquisition link monitoring method built based on this estimation method can be implemented without adding additional hardware, solving the problem in the prior art of lacking a data acquisition link monitoring method that can achieve monitoring effects without adding hardware.

[0097] The above description is only a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the present invention.

Claims

1. An estimation method, characterized in that, The method is applied to a solenoid valve, which includes a valve core. The estimation method includes: calculating an estimated value of the valve core temperature of the solenoid valve based on a first sampled value of the solenoid valve current and a second sampled value of the oil temperature; calculating an estimated value of the valve core resistance of the solenoid valve based on the estimated value of the valve core temperature; and calculating an estimated value of the solenoid valve current based on the estimated value of the valve core resistance.

2. The estimation method according to claim 1, characterized in that, The step of calculating the estimated valve core temperature of the solenoid valve based on the first sampled value and the second sampled value includes: Obtain the temperature rise data of the valve core of the solenoid valve, and obtain the temperature difference-time curve of the valve core; The temperature difference-time curve is fitted with a first-order filtering model to calibrate the temperature rise time coefficient and the temperature rise time constant; wherein, the temperature rise time coefficient is the time when the first-order filtering model reaches its 63% maximum value, and the temperature rise time constant is the time when the first-order filtering model reaches its maximum value. The temperature difference of the valve core is calculated using discrete integration based on the temperature rise time coefficient and the temperature rise time constant; wherein the calculation model is the first-order filtering model; and, The valve core temperature estimate is obtained by adding the temperature difference of the valve core to the second sampled value.

3. The estimation method according to claim 2, characterized in that, The step of calculating the temperature difference of the valve core using discrete integration based on the temperature rise time coefficient and the temperature rise time constant includes: The self-heating coefficient of the valve core is obtained, wherein the self-heating coefficient is obtained by dividing the maximum temperature difference between the valve core and the oil temperature under a preset operating condition by the heat generation power of the valve core under the preset operating condition; the preset operating condition is the condition under which the valve core and the working oil have sufficient heat exchange; and, The temperature difference of the valve core is calculated by discrete integration based on the temperature rise time coefficient, the temperature rise time constant, the resistance reference value of the valve core, the resistance temperature coefficient of the valve core, the self-heating coefficient, and the first sampled value.

4. The data acquisition link monitoring method according to claim 1, characterized in that, The step of calculating the estimated valve core resistance of the solenoid valve based on the estimated valve core temperature includes: The estimated value of the valve core resistance of the solenoid valve is calculated using a linear model based on the reference value of the valve core resistance, the temperature coefficient of the valve core resistance, and the estimated value of the valve core temperature.

5. The data acquisition link monitoring method according to claim 1, characterized in that, The step of calculating the estimated value of the solenoid valve current based on the estimated value of the valve core resistance includes: The current calculation formula is set based on the operating mode of the solenoid valve; and... The estimated value of the valve core resistance is substituted into the current calculation formula to calculate the estimated value of the solenoid valve current.

6. The data acquisition link monitoring method according to claim 5, characterized in that, The solenoid valve operates in PWM mode. The current calculation formula is based on the high-side voltage, duty cycle, equivalent charging resistance of the control loop, equivalent discharging resistance of the control loop, and voltage drop across the freewheeling diode during discharge. The estimated value of the valve core resistance is used in the calculation of the equivalent charging resistance and the equivalent discharging resistance.

7. The data acquisition link monitoring method according to claim 6, characterized in that, The charging equivalent resistance is the sum of the estimated value of the valve core resistance, the current sampling resistance, the connection resistance in the control circuit, and the equivalent resistance of the switching transistor; the discharging equivalent resistance is the sum of the estimated value of the valve core resistance, the current sampling resistance, the connection resistance in the control circuit, and the equivalent resistance of the freewheeling diode.

8. A method for monitoring a data acquisition link, characterized in that, The data acquisition link monitoring method includes: The estimated value of the solenoid valve current is calculated based on the estimation method described in any one of claims 1 to 7; and, The difference between the estimated value and the first sampled value is used to determine whether the acquisition link has failed.

9. The data acquisition link monitoring method according to claim 8, characterized in that, The step of determining whether the acquisition link has failed based on the difference between the estimated value and the first sampled value includes: Calculate an upper threshold and a lower threshold, wherein the upper threshold includes a dynamic upper threshold and a static upper threshold, the static upper threshold being obtained by looking up a table based on the first sampled value, and the dynamic upper threshold being obtained by multiplying the first sampled value by an upper threshold parameter; the lower threshold includes a dynamic lower threshold and a static lower threshold, the static lower threshold being obtained by looking up a table based on the first sampled value, and the dynamic lower threshold being obtained by multiplying the first sampled value by a lower threshold parameter; and, If the difference is greater than the upper threshold, the acquisition link is determined to be faulty, and an overcurrent alarm signal is output; if the difference is less than the lower threshold, the acquisition link is determined to be faulty, and an undercurrent alarm signal is output; otherwise, the acquisition link is determined to be valid.

10. A readable storage medium, characterized in that, The readable storage medium stores a program that, when executed, performs the estimation method as described in any one of claims 1 to 7, or performs the acquisition link monitoring method as described in any one of claims 8 to 9.

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