CN113898778B

CN113898778B - High-speed electromagnetic valve control system and method adapting to working condition and control parameter change

Info

Publication number: CN113898778B
Application number: CN202111150241.0A
Authority: CN
Inventors: 陈晖�; 张泽鑫; 杜恒; 黄惠; 李雨铮; 王小康; 生凯章
Original assignee: Fuzhou Huibang Machinery Equipment Co ltd
Current assignee: Fuzhou Huibang Machinery Equipment Co ltd
Priority date: 2021-09-29
Filing date: 2021-09-29
Publication date: 2023-03-21
Anticipated expiration: 2041-09-29
Also published as: CN113898778A

Abstract

The invention relates to a high-speed electromagnetic valve control system and a method adapting to working conditions and control parameter changes, wherein the system consists of an upper computer, a switching signal generator, a controller, a voltage source, a current sensor, a current differential processing module, a pressure detection system and a high-speed electromagnetic valve, wherein the voltage source consists of a variable positive voltage source and a variable negative voltage source; in the valve core opening stage, whether the valve core is fully opened or not is judged through current and derivative feedback information identification; in the full-open stage of the valve core, high-frequency PWM voltage which is adaptive to pressure working conditions and control parameter changes is applied; and in the valve core closing stage, closing excitation time is optimally distributed, zero current maintaining time and pre-excitation time are maintained, and the amplitude of pre-excitation voltage is adaptively controlled. According to the system and the method, high dynamic control on the high-speed electromagnetic valve can be realized only by setting the control parameters of the switching signals, so that the response time is favorably shortened, the energy consumption is reduced, the duty ratio range of realizing full opening and full closing of the valve core under high frequency is widened, and the accuracy, the adaptability and the robustness of the control are improved.

Description

High-speed electromagnetic valve control system and method adapting to working condition and control parameter change

Technical Field

The invention belongs to the field of electromagnetic valve control, and particularly relates to a high-speed electromagnetic valve control system and method adapting to working conditions and control parameter changes.

Background

The high-speed electromagnetic valve is used as a novel digital control hydraulic control element, and on-off control is used for replacing valve port opening throttle control, so that throttle loss of a valve control system can be greatly reduced, pollution resistance of an electro-hydraulic control system is improved, and hydraulic digitization and high-reliability control are facilitated.

In recent years, researchers have attempted to achieve proportional control effects through high frequency discrete fluid coupling, and the control effect of this technique depends on the dynamic characteristics of high speed solenoid valves in hydraulic systems. Therefore, the dynamic characteristics of high speed solenoid valves are a significant obstacle to the development of digital hydraulic technology. The index for measuring the dynamic characteristic of the high-speed electromagnetic valve is the switching response time of the high-speed electromagnetic valve, the shorter the response time is, the better the dynamic characteristic is, the wider the effective controllable range for realizing the full-opening and full-closing of the valve core under high frequency is, and the high-frequency signal control is more favorable for the deviation regulation and control of the flow. Traditional PWM control makes the case motion open through applying the positive voltage, makes the case motion close through applying zero voltage, inevitably brings the problem that case full-open stage coil current is too big, the energy consumption increases, simultaneously because high-speed solenoid valve self physics delay characteristic leads to the great hysteresis switch signal of case motion, and zero voltage can't effectively make the case close fast, leads to response speed not fast enough, has restricted case full-open full-close's under the high frequency operating capability.

In order to reduce the dynamic response time and make up for the deficiencies of the conventional PWM control, some solutions are proposed in the prior art, but some deficiencies or limitations exist.

(1) By setting the opening feedback current value for judging the full opening of the valve core, the valve core is ensured to be fully opened when the current reaches the value, but the opening feedback current value under different pressure working conditions depends on experimental data measured in advance, the data processing redundancy is increased, and the time lag exists in voltage switching. For example, patent CN105443840B discloses an intelligent control system for an electromagnetic valve and a method thereof, which have the following disadvantages: by performing function fitting on the pressure value tested by the early-stage experiment and the opening current feedback value, and using the fitted result to judge whether the valve element is fully opened, the data processing is more complicated; in addition, in order to ensure that the valve core is fully opened, a larger opening current feedback value needs to be selected in actual measurement, so that time lag exists in voltage switching, namely, due to the existence of coil inductive reactance, when high voltage is switched into maintaining voltage, the current needs to be reduced for a period of time to keep fully opened current, the current change is not timely enough, so that the coil generates redundant current, and the energy consumption is increased.

(2) When the high-speed electromagnetic valve is in a periodic working state of continuous switching, PWM maintaining voltage applied in the full-open stage of the valve core is difficult to adapt to the changing pressure working condition and the switching signal. For example, patent CN105676690B discloses an electromagnetic valve intelligent control system based on voltage pulse width modulation and a method thereof, which have the following defects: the electromagnetic force required for maintaining the full opening of the valve core under different pressure working conditions is different in size, and the PWM maintaining voltage with the duty ratio incapable of being adaptively adjusted along with the duty ratio is difficult to meet the requirement of the changing pressure working condition; moreover, if a PWM holding voltage with a fixed frequency is applied, due to the variation of the control parameters (duty ratio g, period T) of the switching signal, when the falling edge of the switching signal arrives instantaneously, it is difficult to ensure that the real-time current values under different pressure conditions and different control parameters of the switching signal can be exactly at the middle value of the high-frequency flutter current ripple, i.e., the full-open current value is maintained, so that the initial point of the falling is not accurate enough, which is not beneficial to the control of the falling current at high frequency.

(3) The single starting high-voltage excitation causes the valve core starting response speed not to be fast enough; meanwhile, the difference of the opening electromagnetic delay time of the valve core is larger under different pressure working conditions, and the difference of the opening response time is further larger. For example, patent CN105805392B discloses a PWM control method for increasing response speed of a high-speed switching solenoid valve, which is not sufficient in that: the single high-voltage excitation is started, so that the current of the coil still rises from zero in the starting stage of the valve core, and the response is not fast enough; and when the pressure working condition is increased, the required critical opening current value is larger, the coil current rise time is longer, the opening electromagnetic delay time is prolonged, and the opening response time of the high-speed electromagnetic valve is sensitive to pressure change and unstable.

(4) When the duty ratio of the switching signal is high, the coil current is reduced to zero by applying a negative voltage, and then the current cannot be increased to a desired pre-excitation current value even if the pre-excitation voltage having a magnitude equal to the rated voltage is applied. For example, patent CN111828715a discloses a control system and method for realizing rapid movement of an electromagnetic valve, which are deficient in: when the duty ratio of the switching signal is high, the applied negative voltage reduces the coil current to zero, and due to the existence of the zero current maintaining stage, the pre-excitation voltage cannot enable the coil current to rise to the required pre-excitation current value because the pre-excitation time is short, and even cannot enable the coil current to be kept stable near the pre-excitation current value before the excitation high voltage arrives, so that the starting response time of the next period is increased, and the original pre-excitation method is invalid when the duty ratio of the switching signal is high.

Disclosure of Invention

The invention aims to provide a high-speed electromagnetic valve control system and a method adapting to working conditions and control parameter changes, the system and the method can realize high dynamic control on the high-speed electromagnetic valve only by setting control parameters of a switching signal, are beneficial to shortening response time, reducing energy consumption, widening the duty ratio range for realizing full-on and full-off control of a valve core under high frequency, and improve the accuracy, adaptability and robustness of control.

In order to achieve the purpose, the invention adopts the technical scheme that: a high-speed electromagnetic valve control system adapting to working conditions and control parameter changes mainly comprises an upper computer, a switching signal generator, a controller, a voltage source, a current sensor, a current differential processing module, a pressure detection system and a high-speed electromagnetic valve, wherein the voltage source comprises a variable positive voltage source and a negative voltage source;

the output end of the upper computer is connected with the input end of the switching signal generator, the output end of the switching signal generator is connected with the input end of the controller, the output end of the controller is connected with the input end of the voltage source, the output end of the voltage source is connected with the coil of the high-speed electromagnetic valve through the current sensor, the current sensor is connected with the current differential processing module, the output ends of the current sensor, the current differential processing module and the pressure detection system are all connected with the input end of the controller, the pressure detection system comprises three pressure sensors, wherein the first pressure sensor is connected with the oil inlet of the high-speed electromagnetic valve, the second pressure sensor is connected with the control port of the high-speed electromagnetic valve, and the third pressure sensor is connected with the oil return port of the high-speed electromagnetic valve;

the upper computer sets control parameters (duty ratio g and period T) of the switching signals; the switching signal generator outputs high-low level switching signals with variable duty ratio and variable frequency according to control parameters set by an upper computer; the controller calculates the switching time of each voltage and the duration and the size of each voltage; the output amplitude of the variable positive voltage source is 0-U _Excitation A magnitude of voltage, the magnitude of the negative voltage source output being-U _Excitation A negative voltage of magnitude; and the current differential processing module performs differential derivation and filtering processing on the current value detected by the current sensor to obtain current derivative information.

Furthermore, the controlled high-speed electromagnetic valve is a single-electromagnet and single-coil electromagnetic valve, the pressure of the oil inlet liquid acts on the closing direction of the valve core all the time, and U _Excitation Is the rated working voltage of the high-speed electromagnetic valve.

The invention also provides a control method of the high-speed electromagnetic valve adapting to the working condition and the change of the control parameter, the valve core of the high-speed electromagnetic valve is divided into an excitation opening stage, a full opening stage, an excitation closing stage, a zero current maintaining stage and a pre-excitation stage in sequence in a switching period, a high-low level switching signal with the duty ratio of g and the period of T is set, g and T are control parameters, the high-speed electromagnetic valve is controlled by changing the control parameters g and T, the high-level stage time of the switching signal obtained by the control parameters is T multiplied by g, and the low-level stage time is T multiplied by (1-g);

when the rising edge of the switching signal comes, in the starting excitation stage, the amplitude is applied to be U _Excitation The high voltage is excited, and in the process, the sampling information of the current and the current derivative is used as a real-time feedback signal to judge whether the valve core is completely opened or not, and the judgment result is used as the basis for judging whether the valve core enters a fully-opened holding stage or not; applying high-frequency PWM voltage of control parameters of duty ratio self-adaptive pressure working condition and frequency self-adaptive switching signal at the full-open keeping stage, wherein the amplitude of the high-frequency PWM voltage is U _Excitation (ii) a When the falling edge of the switching signal arrives, the optimized distribution excitation closing time, the zero current maintaining time and the pre-excitation time are calculated according to the low level time and the pressure working conditionAfter the optimized distribution, the time for maintaining the zero current is a positive value or a zero value; during the off-excitation phase, an amplitude of-U is applied _Excitation And controlling the duration of the excitation negative voltage; in the phase of maintaining zero current, applying zero voltage; in the pre-excitation stage, the application amplitude is selected to be U according to the pre-excitation time and the expected pre-excitation current value _Excitation Pre-excitation voltage of the amplitude variation value range is 0-U _Excitation Pre-excitation voltage of;

the duration and the size of the voltage at each stage are automatically regulated according to the pressure working condition and the change of the control parameter of the switching signal, and the pressure working condition is the pressure working condition of an oil inlet of the high-speed electromagnetic valve.

Further, in the continuous switching period, the specific method for circularly controlling the high-speed electromagnetic valve under the working condition of 5-20 MPa pressure comprises the following steps:

step S1: the pressure of an oil inlet of the high-speed electromagnetic valve, the pressure difference between the oil inlet and the control port and the pressure difference between the control port and the oil return port in the current switching period are obtained through updating, and the critical opening current I under the current pressure working condition is calculated _on And critical off current I _off And further calculating to obtain an expected pre-excitation current value I according to the critical opening current, the excitation high voltage and the parameters of the high-speed electromagnetic valve including the preset optimal opening electromagnetic delay time _{Pre-excitation} ；

Step S2: setting high and low level switch signals with duty ratio g and period T, applying excitation high voltage to drive the valve core to move and open when the high level rising edge of the switch signals comes, and judging whether the valve core moves to be completely opened or not by a characteristic point identification method based on real-time sampling current and derivative information thereof and current change trend;

and step S3: when the valve core is fully opened, recording the real-time t in the current period _{Characteristic point} Calculating to obtain the variable duty ratio value g of the high-frequency PWM voltage for maintaining the full opening of the valve core according to the current pressure working condition of the oil inlet and the pressure difference of the valve port _on (ii) a According to the control parameter g of the switch signal at the time _on And t _{Characteristic point} To obtain a variable frequency f of the high-frequency PWM voltage _on (ii) a And will beExciting high voltage to be switched into high-frequency PWM voltage, controlling real-time current to maintain a high-frequency flutter mode at a position of keeping a full-opening current value, wherein the keeping full-opening current value is the coil current required by maintaining full opening of a valve core;

and step S4: when the real-time T in the period reaches T multiplied by g, the high-frequency PWM voltage is switched to be an excitation negative voltage, and the time T required by the current to be reduced from the full-open current value to the zero current value is calculated ₁ And the time t required for the current to rise from zero current value to the desired pre-excitation current value ₂ According to t ₁ And t ₂ Obtaining a time switching threshold value for judging whether zero voltage is applied, and jumping to the step S5 when the time switching threshold value is larger than zero; when the time switching threshold value is smaller than zero, jumping to the step S7;

step S5: controlling the excitation negative voltage to reduce the current value to zero, and switching the excitation negative voltage to zero voltage to maintain zero current after the current is reduced to zero, wherein the zero voltage duration is T (1-g) -T ₁ -t ₂ ；

Step S6: when the zero voltage is completely applied, the zero voltage is switched to be U in amplitude _Excitation Pre-excitation voltage of t _{Pre-excitation} ＝t ₂ Controlling the real-time current to reach the expected pre-excitation current value I at the end moment of the current switching period _{Pre-excitation} Then jumping to step S1;

step S7: controlling the exciting negative voltage to reduce the current value to 0-I _off And recording the time t of the duration of the negative voltage excitation ₃ Obtaining a pre-excitation voltage having a duration of T × (1-g) -T ₃ ；

Step S8: when the excitation negative voltage reduces the current value to the closing current threshold value, zero voltage is not applied, the excitation negative voltage is switched to be pre-excitation voltage with amplitude adaptive pre-excitation time and pressure working condition, and the variable amplitude range is 0-U _Excitation At the end of the current cycle, the current value is brought to the desired pre-excitation current value I _{Pre-excitation} And then jumps to step S1.

Further, when the spool displacement movement is maximized, completing full opening, it occursThe valve core is fully opened, and the current of the characteristic point is represented by the way that the current rises from zero to a steady-state value U _Excitation /R _{Resistance value of coil} The lowest point of the curve with the curvature changing continuously is gradually decreased and then increased, and whether the valve core is fully opened or not is judged according to the current change condition of the characteristic point;

when the characteristic points are difficult to judge only through current change, the identification judgment is carried out by combining current derivative information;

the method for identifying and judging the valve core full-open characteristic points comprises the following steps:

step Q1: setting sampling step length, monitoring, sampling and filtering the coil current and the current derivative thereof;

step Q2: judging whether the real-time in the current period is less than T multiplied by g, if so, resetting the sampling counter, otherwise, sampling and filtering the coil current and the current derivative thereof again;

and step Q3: judging whether the current is in a rising stage and whether the real-time current reaches a critical starting current value, if so, turning to the next step, and if not, resetting the sampling counter again;

step Q4: selecting current values I of the first two sampling moments, the last sampling moment and the current sampling moment ₁ 、I ₂ 、I ₃ And the derivative value of the current I ₁ dot、I ₂ dot、I ₃ dot if I is satisfied ₁ >I ₂ And I is ₂ <I ₃ Entering the next step; if the current information does not satisfy I ₁ >I ₂ And I ₂ <I ₃ Screening and identifying the current derivative information to judge whether I is satisfied ₂ dot<I ₁ dot and I ₂ dot<I ₃ during dot, if the dot is satisfied, entering the next step, and if the dot is not satisfied, reselecting the sampling current and derivative information;

step Q5: and when the current value continues to rise, if the current value rises, the sampling counter counts each newly increased incremental current value, when the count value reaches a preset value, the sampling counter is cleared, the fully-open characteristic point of the valve core is identified at present, and if the current value does not rise, the step Q4 is skipped.

Further, the method for acquiring the variable duty ratio and the variable frequency of the high-frequency PWM voltage adapted to the pressure condition and the change of the switching signal control parameter includes:

the variable duty cycle is:

wherein P is _s Is the pressure of the oil inlet, A is the area of action of the valve core, F _s1 Is a steady-state hydrodynamic force at the full-open stage of the valve element, F _s1 The numerical value of (D) is obtained by calculating the pressure difference between the oil inlet and the control port, mu ₀ Air permeability, S is the area of the magnetic flux, R _m1 Is the equivalent magnetic resistance when the valve core is fully opened, epsilon is the magnetic leakage coefficient, N is the number of turns, i _k Current compensation value, R, to maintain full opening of the spool _{Coil resistance} Is the coil resistance value;

the variable frequency is:

f＝1/[(T×g-t _{characteristic point} )/(n+1/2+g _on /2)]

Wherein n and g × (T/T) _max ) Proportional ratio, T _max The real-time current is controlled by the variable frequency f to be exactly the middle value of the high-frequency flutter current ripple at the moment of the action of the negative voltage for the maximum period of work required by the high-speed electromagnetic valve, wherein the middle value of the high-frequency flutter current ripple is the value of keeping the full-open current.

Further, the method for acquiring the time switching threshold value comprises the following steps:

the time switch threshold is set by T x (1-g) -T ₁ -t ₂ When the time switching threshold is larger than zero, a zero current maintaining stage still exists in the low level stage of the switching signal; when the time switching threshold is less than zero, the zero current maintaining stage does not exist in the low level stage of the switching signal.

Further, the method for acquiring the expected pre-excitation current value under the real-time pressure working condition comprises the following steps:

calculating critical opening current I under real-time oil inlet pressure and real-time valve port pressure difference _on And critical pointClosed current I _off According to I _on The desired pre-excitation current value is obtained as follows:

I _{pre-excitation} ＝(U _Excitation -exp(R _{Resistance value of coil} ×t _delay /L _off )×(U _Excitation -I _on ×R _{Resistance value of coil} ))/R _{Resistance value of coil}

Wherein, I _{Pre-excitation} To expect the pre-excitation current value, R _{Resistance value of coil} Is the coil resistance value, t _delay Selecting the optimal value of the starting electromagnetic delay time according to the starting electromagnetic delay time under the working condition of small pressure, L _off Is the equivalent inductance of the valve core closing stage.

Further, according to the expected pre-excitation current under the real-time pressure working condition, when the time switching threshold value is less than zero, the amplitude value is obtained to be 0-U _Excitation The adaptive pre-excitation voltage is:

U _{pre-excitation} ＝((I _{Pre-excitation} -I _{Threshold value} )/(1-exp(-t _{Pre-excitation} ×R _{Resistance value of coil} /L _off ))+I _{Threshold value} )×R _{Coil resistance}

Wherein, I _{Threshold value} In order to close the current threshold, the negative voltage is excited under the condition that the time switching threshold is less than zero to lead the current of the coil to fall to the lowest point, and the condition that 0 is more than I is satisfied _{Threshold value} ＜I _off Can follow I _off Is automatically adjusted by the change of t _{Pre-excitation} For a desired pre-excitation time, i.e. t _{Pre-excitation} ＝T×(1-g)-t ₃ 。

Compared with the prior art, the invention has the following beneficial effects:

(1) Through the online identification of the valve element full-open characteristic point, whether the valve element is completely opened or not is judged, the hardware cost of a high-precision high-end displacement sensor and the complexity of early experimental processing data are reduced, the switching time of excitation high voltage and high-frequency PWM voltage is more accurate, and the time lag of voltage switching is reduced. The method ensures that the opportunity of exciting high voltage to be switched into high-frequency PWM voltage is more accurate, reduces energy consumption caused by current reduction after voltage switching, and ensures that real-time current can reach steady-state full-open current in time.

(2) The high-frequency PWM voltage of the control parameter of the duty ratio self-adaptive pressure working condition and the frequency self-adaptive switching signal is applied in the fully-open keeping stage, so that the control adaptability and accuracy are improved. Under the working condition of variable pressure, the duty ratio of the high-frequency PWM voltage always enables the valve core to be just maintained in a fully-opened stable state, and meanwhile, the energy consumption caused by redundant current in the fully-opened stage of the valve core is reduced; and even if the pressure working condition and the control parameter of the switching signal are changed, the frequency of the high-frequency PWM voltage can ensure that the real-time current value is just in the state of keeping the full-open current value when the falling edge of the switching signal arrives, so that the initial point of current falling at the moment of negative voltage excitation is more accurate, and the control under the high-frequency switching signal is more accurate.

(3) The valve core opening response speed is further increased by applying the pre-excitation voltage which can be adaptively controlled before the next switching signal comes; on the basis, when the expected pre-excitation current value is calculated, the real-time pressure working condition and the optimal starting electromagnetic delay time are considered, the problem that the starting response time is sensitive to pressure change is solved while response is improved, the starting electromagnetic delay time can be consistent and unchanged under different pressure working conditions and the same high-voltage excitation, the starting response time is further enabled to have robustness under different pressure working conditions, and system-level application of multi-valve simultaneous control under complex pressure working conditions is facilitated.

(4) In the low-level stage of the switching signal, the optimal distribution of the time of exciting the negative voltage, the zero voltage and the pre-excitation voltage is realized, no matter the duty ratio of the switching signal is lower or higher, the actual coil current can accurately rise to the expected pre-excitation current value at the end moment of a switching period, and meanwhile, the energy consumption caused by redundant current in the closing stage of the valve core is reduced as much as possible. That is, when the duty ratio of the switching signal is low, the negative voltage is switched to zero voltage at the moment when the current of the control coil is reduced to zero, and the negative voltage is switched to zero voltage at zero currentThe maintenance phase reduces energy consumption and ensures that the amplitude is U _Excitation The current is accurately increased from zero to a desired pre-excitation current value under the pre-excitation voltage; when the duty ratio of the switching signal is high, the optimized distribution mode ensures that the amplitude value of the negative voltage is immediately switched to 0-U at the moment of the closing current threshold value when the current of the control coil is reduced to be below the critical closing current value _Excitation The self-adaptive pre-excitation voltage can still smoothly increase the current to the expected pre-excitation current value, and the valve core is ensured to be completely closed.

Drawings

FIG. 1 is a schematic block diagram of a system architecture of an embodiment of the present invention;

FIG. 2 is a functional diagram of an embodiment of the present invention;

FIG. 3 is a flow chart of a method implementation of an embodiment of the present invention;

FIG. 4 is a schematic diagram of the relationship between spool displacement and current derivatives in an embodiment of the present invention;

FIG. 5 is a graph illustrating the relationship between the measured current and the current derivative under different pressure conditions according to an embodiment of the present invention;

FIG. 6 is a flow chart of the identification and determination of the fully open characteristic points of the valve element in the embodiment of the present invention;

FIG. 7 is a diagram illustrating the response of the present invention to the displacement of the spool of a high-speed solenoid valve controlled by a low duty cycle switching signal;

FIG. 8 is a graph of the current variation under the low duty cycle switching signal for the high speed solenoid valve controlled by the present method in the embodiment of the present invention;

FIG. 9 is a valve core displacement response diagram of a high-speed solenoid valve controlled by the method under a high duty cycle switching signal according to an embodiment of the present invention;

FIG. 10 is a graph of the current variation under the high duty cycle switching signal for the high speed solenoid valve controlled by the present method in an embodiment of the present invention;

FIG. 11 is a graph comparing the displacement response of the valve element under separate control of the present method and conventional PWM in an embodiment of the present invention;

FIG. 12 is a graph showing the displacement response and current change of the valve core of the high-speed solenoid valve under the high-frequency switching signal of 200Hz by the method and the conventional PWM in the embodiment of the invention.

In fig. 1: 1-an upper computer; 2-a switching signal generator; 3-a controller; 4-a variable positive voltage source; 5-a negative voltage source; 6-a current sensor; 7-a current differential processing module; 8-high speed electromagnetic valve; 9-a pressure detection system; 10-a throttle valve; p-an oil inlet of the high-speed electromagnetic valve; a-a control port of the high-speed electromagnetic valve; t-oil return port of high-speed electromagnetic valve.

Detailed Description

The invention is further explained below with reference to the drawings and the embodiments.

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise. The numerical values presented are also merely preferred numerical values describing particular embodiments.

As shown in fig. 1, the present embodiment provides a high-speed electromagnetic valve control system adapted to working conditions and control parameter changes, and the control system is composed of an upper computer 1, a switching signal generator 2, a controller 3, a voltage source, a current sensor 6, a current differential processing module 7, a high-speed electromagnetic valve 8, and a pressure detection system 9. Wherein the voltage source consists of a variable positive voltage source 4 and a negative voltage source 5. The output amplitude of the variable positive voltage source 4 is 0-U _Excitation The voltage of the voltage source is used in a starting excitation stage, a keeping full-open stage, a zero current stage and a pre-excitation stage; the output amplitude of the negative voltage source 5 is-U _Excitation A negative voltage of a magnitude used during the off-drive phase.

The output end of the upper computer 1 is connected with the input end of the switching signal generator 2, the output end of the switching signal generator 2 is connected with the input end of the controller 3, the output end of the controller 3 is connected with the input ends of the

voltage sources

4 and 5, the output ends of the

voltage sources

4 and 5 are connected with the coil of the high-speed electromagnetic valve 8 through the current sensor 6, the current sensor 6 is connected with the current differential processing module 7, the current sensor 6, the current differential processing module 7 and the output end of the pressure detection system 9 are connected with the input end of the controller 3, the

voltage sources

4 and 5 can apply voltage to the coil through the current sensor 6, and the current sensor 6 can also detect the coil current of the high-speed electromagnetic valve 8. The pressure detection system 9 comprises three pressure sensors, the three pressure sensors are respectively connected with an oil inlet P, a control port A and an oil return port T of the high-speed electromagnetic valve 8 and used for detecting the pressure of each working port, and a throttle valve 10 is connected to a connecting loop of the oil return port T and used as a load. Wherein, the high-speed solenoid valve is a solenoid valve with a single electromagnet and a single coil, and the hydraulic pressure of the oil inlet always acts on the closing direction of the valve core, U _Excitation The rated working voltage of the high-speed electromagnetic valve is adopted, and the pressure working condition is the pressure working condition of an oil inlet of the high-speed electromagnetic valve.

The upper computer 1 sets control parameters (duty ratio g and period T) of the switching signal; the switching signal generator 2 outputs high and low level switching signals with variable duty ratio and variable frequency according to control parameters set by an upper computer; the controller 3 comprises a preset control algorithm and a preset formula, and calculates the switching time of each voltage and the duration and the size of each voltage according to the acquired switching signal, the detected current information, current derivative information and pressure information; the current differential processing module 7 performs differential derivation and filtering processing on the current value detected by the current sensor 6 to obtain current derivative information.

Fig. 2 is a working principle diagram of the present embodiment, which reflects the relationship between the switching signal, the voltage signal, the coil current and the spool displacement under the control method of the present invention.

In this embodiment, the preset high-low level switch signal with duty ratio g and period T has a high level phase time of T × g and a low level phase time of T × (1-g), and g and T are control parameters input by the upper computer. And optimally distributing the excitation closing time, the zero current maintaining time and the pre-excitation time according to the low level time.

Where, fig. 2 (a) shows that when the switching signal low level time T × (1-g) is large, one switching cycle is divided into five stages, D1: start-up excitation phase, D2: fully open holding stage, D3: off excitation phase, D4: zero current maintenance phase, D5: a pre-excitation phase.

(1) When the rising edge of the switching signal comes, in the starting excitation stage, the amplitude is applied to be U _Excitation The valve core full-open characteristic point is identified by taking the sampling information of the current and the derivative thereof as a real-time feedback signal, and whether the valve core is completely opened or not is judged according to the characteristic point, and the judgment result is used as the basis for judging whether the valve core needs to enter the full-open holding stage or not; and in the fully-open keeping stage, applying high-frequency PWM voltage with duty ratio self-adaptive pressure working condition and frequency self-adaptive to the control parameter of the switching signal. (2) When the falling edge of the switching signal comes, in the off-excitation phase, the amplitude is applied to be-U _Excitation The excitation negative voltage of (2) controls the coil current to accurately reduce from a full-open current value to a zero current value; in the phase of maintaining zero current, applying zero voltage; during the pre-excitation phase, an amplitude of U is applied _Excitation The coil current can smoothly rise to the expected pre-excitation current value at the end of a switching period under different pressure working conditions.

Fig. 2 (b) shows that when the switching signal low level time T × (1-g) is small, one switching cycle is divided into four stages, D1: start-up excitation phase, D2: fully open holding stage, D3: off excitation phase, D4: a pre-excitation phase.

Among them, fig. 2 (b) differs from fig. 2 (a) in that: (1) During the off-excitation phase, an amplitude of-U is applied _Excitation The coil current is reduced from a hold full open current value to a close current threshold that causes the valve element to fully close. (2) In the pre-excitation stage, the applied amplitude is 0-U _Excitation The pre-excitation voltage, and the amplitude of the pre-excitation voltage is adaptive to the change of the pressure working condition and the pre-excitation time, so that the current switch is realizedWhen the signal is in a high duty ratio (the low level time is small), the current can still be accurately increased to the expected pre-excitation current value. (3) Compared to fig. 2 (a), fig. 2 (b) does not have the zero current sustain phase.

Fig. 3 is a flowchart of a method implementation of the present embodiment. As shown in FIG. 3, the implementation steps of the cycle control of the high-speed electromagnetic valve under the pressure working condition of 5-20 MPa in the continuous switching period are as follows:

step S1: the pressure P of the oil inlet of the high-speed electromagnetic valve in the current switching period is obtained through updating _s Pressure difference delta P between oil inlet and control port ₁ Pressure difference delta P between the control port and the oil return port ₂ Calculating the critical opening current I under the current pressure working condition _on And critical off current I _off And further based on the critical turn-on current, the excitation high voltage, and the preset optimal turn-on electromagnetic delay time t _delay Calculating to obtain expected pre-excitation current value I _{Pre-excitation} 。

Step S2: and setting a high-low level switching signal with the duty ratio of g and the period of T, applying excitation high voltage to drive the valve plug to move and open when the high level rising edge of the switching signal comes, and judging whether the valve plug moves to be completely opened or not by a characteristic point identification method based on real-time sampling current and derivative information thereof and current change trend.

And step S3: when the valve core is fully opened, recording the real-time t in the current period _{Characteristic point} Calculating to obtain the variable duty ratio value g of the high-frequency PWM voltage for maintaining the full opening of the valve core according to the current pressure working condition of the oil inlet _on (ii) a According to the control parameter g of the switch signal at the time _on And t _{Characteristic point} To obtain a variable frequency f of the high-frequency PWM voltage _on (ii) a And switching the excitation high voltage into high-frequency PWM voltage, and controlling the real-time current to maintain a high-frequency flutter mode at a full-opening current value, wherein the full-opening current value is the coil current required for maintaining the full opening of the valve core.

And step S4: when the real-time T in the period reaches T multiplied by g, the high-frequency PWM voltage is switched to be an excitation negative voltage, and the current is calculated to be reduced to zero from the value of keeping the full-open currentTime t required for current value ₁ And the time t required for the current to rise from zero current value to the desired pre-excitation current value ₂ According to t ₁ And t ₂ Obtaining a time switching threshold value for judging whether zero voltage is applied, and jumping to the step S5 when the time switching threshold value is larger than zero; and when the time switching threshold value is smaller than zero, jumping to the step S7.

Step S5: controlling the excitation negative voltage to reduce the current value to zero, and switching the excitation negative voltage to zero voltage to maintain zero current after the current is reduced to zero, wherein the zero voltage duration is T (1-g) -T ₁ -t ₂ 。

Step S6: when the zero voltage is completely applied, the zero voltage is switched to be U in amplitude _Excitation Pre-excitation voltage of t _{Pre-excitation} ＝t ₂ Controlling the real-time current to reach the expected pre-excitation current value I at the end moment of the current switching period _{Pre-excitation} And then jumps to step S1.

Step S7: controlling the excitation negative voltage to reduce the current value to 0-I _off In between, and recording the time t during which the negative voltage is excited ₃ Obtaining a pre-excitation voltage having a duration of T × (1-g) -T ₃ 。

In this embodiment, step S1 is described as I _on Is obtained by deduction and calculation according to the critical force balance state of the valve core from closing to opening,

in the same way, I _off Is obtained by derivation calculation according to the critical force balance state of the valve core from opening to closing,

and further obtaining the expected pre-excitation current value as follows: i is _{Pre-excitation} ＝(U _Excitation -exp(R _{Resistance value of coil} ×t _delay /L _off )×(U _Excitation -I _on ×R _{Resistance value of coil} ))/R _{Resistance value of coil} . Wherein, P _s Is the pressure of the oil inlet; a is the valve core action area; f _s1 Is a steady-state hydrodynamic force of the valve core in the full-open stage, F _s2 Steady-state hydrodynamic forces for the closing phase of the valve element, F _s1 The value of (a) is required to pass through the pressure difference delta P between the oil inlet and the control port ₁ Is calculated to obtain F _s2 The value of (d) is required to be determined by the pressure difference Δ P between the control port and the return port ₂ The transient liquid dynamic numerical value is extremely small, so that the valve core can be not considered when the stress of the valve core is analyzed; r _m2 And is the equivalent magnetic resistance when the valve core is fully closed; r _m3 The equivalent magnetic resistance when the valve core is fully opened; r _{Resistance value of coil} Is the coil resistance value; mu.s ₀ Air permeability; s is the magnetic flux area; epsilon is a magnetic leakage coefficient; n is the number of turns; l is _off Equivalent inductance at the valve element closing stage: t is t _delay For a preset optimum value of the delay time of the switching on electromagnet, i.e. with an applied amplitude of U _Excitation The excitation high voltage enables the coil current to rise from the pre-excitation current to the optimal time value required by the critical opening current, the value is selected according to the opening electromagnetic delay time under the working condition of 5MPa oil inlet pressure, the opening electromagnetic delay time of the valve is guaranteed to be consistent and unchanged even under different pressure working conditions and the same excitation high voltage, and the robustness of the opening response time to pressure change is improved.

In the embodiment, under the variable-pressure working condition, the difference between the expected pre-excitation current value and the critical opening current value is not a fixed value, and the difference between the full-opening current value and the closing current threshold value is kept to be not a fixed value.

In this embodiment, for the high-frequency PWM voltage mentioned in step S3, the duty ratio of the voltage is adaptively adjusted according to the change of the pressure condition of the oil inlet, and the frequency is adaptively adjusted according to the change of the control parameter of the switching signal:

variable duty cycle of

Wherein P is _s Is the pressure of the oil inlet, A is the area of action of the valve core, F _s1 Is a steady-state hydrodynamic force of the valve core in the full-open stage, F _s1 The value of (a) requires a pressure difference Δ P between the oil inlet and the control port ₁ Calculated to obtain ₀ Is air permeability, S is magnetic flux area, R _m1 Is the equivalent reluctance when the valve core is fully opened, and R _m1 ＝R _m3 Epsilon is magnetic leakage coefficient, N is number of turns, i _k The current compensation value for maintaining the full opening of the valve core and the electromagnetic force in the full opening stage have certain disturbance tolerance. The variable frequency is: f =1/[ (T × g-T) _{Characteristic point} )/(n+1/2+g _on /2)]Wherein n is equal to g × (T/T) _max ) Proportional ratio, T _max The frequency of the high-frequency PWM voltage signal ensures that when the falling edge of the switching signal comes, the current value at the sampling moment is just at the calculated and maintained full-open current value, the initial point of the current falling is more accurate, and the amplitude change of the high-frequency flutter current does not influence the full-open state of the valve core.

In the present embodiment, the time switching threshold described for step S4 is defined by T × (1-g) -T ₁ -t ₂ When the time switching threshold is larger than zero, a zero current maintaining stage still exists in the low level stage of the switching signal; when the time switching threshold is less than zero, the zero current maintaining stage does not exist in the low level stage of the switching signal.

In the embodiment, according to the expected pre-excitation current under different pressure working conditions, the amplitude value of 0-U is further obtained _Excitation The adaptive pre-excitation voltage is: u shape _{Pre-excitation} ＝((I _{Pre-excitation} -I _{Threshold value} )/(1-exp(-t _{Pre-excitation} ×R _{Resistance value of coil} /L _off ))+I _{Threshold value} )×R _{Resistance value of coil} . Wherein, I _{Threshold value} For closing the current threshold, the negative voltage is excited under the condition that the time switching threshold is less than zero so that the coil current is lowered to the lowest point, and I is satisfied _{Threshold value} ＝kI _off ，0<k is less than or equal to 0.4 and can follow I _off The change of (2) is automatically adjusted; t is t _{Pre-excitation} For the pre-excitation time, t _{Pre-excitation} ＝T×(1-g)-t ₃ 。

Fig. 4 to 6 show the expressions of the current and its derivative at the valve element full-open characteristic point and the identification and judgment method of the characteristic point in the present embodiment.

In the present embodiment, for convenience of explanation, fig. 4 shows the relationship among the spool displacement, the coil current, and the current derivative at the instant when the spool displacement is moved to the maximum and full opening is achieved, taking PWM control as an example. The determination as to whether the valve element displacement is fully open is made based on the valve element fully open characteristic point shown in fig. 4. The current at the characteristic point is represented by the form: the coil current rises from zero to a steady-state value U _Excitation /R _{Resistance value of coil} The reason for the lowest point of the curve that the curvature is constantly changed after the section between the two points is decreased gradually is that the moving armature moves to change the inductance and cause the appearance of the reverse electromotive force, and when the moving armature does not move any more after the valve core is fully opened, the reverse electromotive force disappears and the current continues to rise.

Fig. 5 preferably shows that when the coil excitation speed is fast or is influenced by the operating conditions, so that it is difficult to identify the characteristic points according to the current variation, the screening identification can be further performed by the current derivative, and the implementation flow is as shown in fig. 6:

step Q2: judging whether the real-time T in the current period is less than T multiplied by g, if yes, resetting the sampling counter Count, and otherwise, sampling and filtering the coil current and the current derivative thereof again;

step Q4: selecting current values I of the first two sampling moments, the last sampling moment and the current sampling moment ₁ 、I ₂ 、I ₃ And a value of the derivative of the current I ₁ dot、I ₂ dot、I ₃ dot if satisfy I ₁ >I ₂ And I ₂ <I ₃ Entering the next step; if the current information does not satisfy I ₁ >I ₂ And I ₂ <I ₃ Screening and identifying the current derivative information to judge whether I is satisfied ₂ dot<I ₁ dot and I ₂ dot<I ₃ during dot, if the dot is satisfied, entering the next step, and if the dot is not satisfied, reselecting the sampling current and derivative information;

step Q5: judging whether the current value continuously rises, if so, counting each newly increased incremental current value by the sampling counter, and when the count value reaches a preset value NN, indicating that the current keeps a continuous rising trend in a short time; at the moment, the sampling counter is cleared, and the valve core has reached the maximum displacement when the valve core full-open characteristic point is identified at present; if not, go to step Q4.

The count value NN is determined by the sampling step size.

7-10 show the control effect of the present embodiment on the high-speed solenoid valve under the switching signals of different oil inlet pressure working conditions, the same frequency and different duty ratios. For comparison, in fig. 7 to 10, the valve core and the current curve at the initial time of the first period have no pre-excitation voltage, and the valve core and the current curve at the initial time of the second period have the pre-excitation voltage.

In this embodiment, fig. 7 shows that, for a switching signal with a frequency of 25Hz and a duty cycle of 0.5, under different pressure conditions, due to the action of the adaptive pre-excitation voltage, the opening electromagnetic delay time of the valve is consistent and unchanged, and further, the difference of the opening response time is smaller under the pressure change. The specific embodiment is that the valve core displacement curves are consistent at the rising time from 0, and even if the opening mechanical delay exists, the displacement curves of the valve core opening stage are still close to overlap. The current curve of fig. 8 corresponds to the valve element displacement curve of fig. 7, wherein the high-frequency flutter mode maintains the change of the fully-open current adaptive pressure working condition, and when the excitation negative voltage is applied to make the current decrease from the maintained fully-open current value, the initial point of the decrease is the calculated maintained fully-open current value, so that the initial point of the decrease is more accurate. And, it is desirable that the pre-excitation current value always be adaptive to changes in pressure conditions.

In this embodiment, fig. 9 shows the control effect of the method on the displacement of the valve element of the high-speed electromagnetic valve under the switching signal with the frequency of 25Hz and the duty ratio of 0.95, the reflected characteristics are the same as those in fig. 7, and it can be seen that the opening electromagnetic delay time of the valve is consistent and unchanged, that is, the time when the displacement curve of the valve element starts to rise from 0 is consistent. Fig. 10 is different from fig. 8 in that (1) at a high duty ratio of the switching signal (when the low level time is short), the zero current maintaining stage may not be set, and only the coil current is ensured to be decreased to the closing current threshold; (2) The applied pre-excitation voltage is in the range of 0-U _Excitation The voltage of the adaptive regulation. Similarly, the initial value of the drop of the holding full-open current in fig. 10 and the pre-excitation current value are both the same as those in fig. 8, and the pre-excitation current value can always adapt to the change of the pressure condition.

From fig. 7 and 9, the electromagnetic opening delay time under the condition of 20MPa pressure is reduced by delta t under the action of the adaptive pre-excitation voltage _delay = 0.00135- (0.04025-0.04))/0.00135 × 100% ≈ 81.5%. The opening electromagnetic delay time under each pressure working condition is consistent and unchanged, and because the influence of mechanical delay is small, the opening response time has robustness to the pressure working condition change.

11-12 compare the control effect of the control method of the present invention with the conventional PWM control method on the high speed solenoid valve under the same inlet pressure condition. For comparison, in fig. 12, the valve core and the current curve at the first period initial time have no pre-excitation voltage, and the pre-excitation voltage does not act until the second period initial time.

In this embodiment, it can be seen from fig. 11 that the control of the present invention reduces the turn-on response time by Δ t due to the adaptive pre-excitation voltage compared to the PWM control _on = (0.0022-0.001125)/0.0022 × 100% ≈ 48.9%; due to the combined action of the self-adaptive high-frequency PWM voltage and the excitation negative voltage for maintaining the valve core to be fully opened, the closing response time is reduced by delta t _off = ((0.0314-0.02) - (0.0211-0.02))/(0.0314-0.02) × 100% ≈ 90.4%. From FIG. 12, it can be seen that the PWM control operates at 200HzBecause the response is not fast enough, the valve core can not be closed once being opened, namely, the zero voltage duration under the PWM control is shorter than the closing response time, and the valve core can not be closed completely.

Compared with the principle of fig. 2, with respect to fig. 8, 10 and 12, under the action of the excitation negative voltage, the demagnetization speed of the coil is high, so that the reverse current at the current reduction stage is not obvious yet, and at this time, the valve element can still realize the full-off control.

The foregoing is directed to preferred embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. However, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the protection scope of the technical solution of the present invention.

Claims

1. A high-speed electromagnetic valve control system adapting to working conditions and control parameter changes is characterized by mainly comprising an upper computer, a switching signal generator, a controller, a voltage source, a current sensor, a current differential processing module, a pressure detection system and a high-speed electromagnetic valve, wherein the voltage source comprises a variable positive voltage source and a negative voltage source;

the upper computer sets control parameters of the switching signals; the switching signal generator outputs high and low level switching signals with variable duty ratio and variable frequency according to control parameters set by the upper computer; the controller calculates the switching time of each voltage and the duration and the size of each voltage; the output amplitude of the variable positive voltage source is 0-U _Excitation A voltage of magnitude, the negative voltage source output amplitude being-U _Excitation A negative voltage of magnitude; and the current differential processing module performs differential derivation and filtering processing on the current value detected by the current sensor to obtain current derivative information.

2. The operating condition and parameter variation adaptive high-speed electromagnetic valve control system according to claim 1, wherein the controlled high-speed electromagnetic valve is a single electromagnet or single coil electromagnetic valve, the hydraulic pressure of the oil inlet always acts on the closing direction of the valve core, and U is the pressure of the oil inlet _Excitation Is the rated working voltage of the high-speed electromagnetic valve.

3. A high-speed electromagnetic valve control method adapting to working conditions and control parameter changes is characterized in that a valve core of the high-speed electromagnetic valve is sequentially divided into an excitation opening stage, a full-opening keeping stage, an excitation closing stage, a zero current maintaining stage and a pre-excitation stage in a switching period, a high-low level switching signal with a duty ratio of g and a period of T is set, g and T are control parameters, the high-speed electromagnetic valve is controlled by changing the control parameters g and T, the high-level stage time of the switching signal obtained by the control parameters is T multiplied by g, and the low-level stage time is T multiplied by (1-g);

when the rising edge of the switching signal comes, in the starting excitation stage, the amplitude is applied to be U _Excitation The high voltage is excited, and in the process, whether the valve core is completely opened or not is judged by taking the sampling information of the current and the current derivative as a real-time feedback signal, and the judgment result is used as whether the valve core enters the valve or notThe basis of the fully open stage is kept; applying high-frequency PWM voltage of control parameters of duty ratio self-adaptive pressure working condition and frequency self-adaptive switching signal at the full-open keeping stage, wherein the amplitude of the high-frequency PWM voltage is U _Excitation (ii) a When the falling edge of the switching signal arrives, calculating the optimized distribution closing excitation time, the zero current maintaining time and the pre-excitation time according to the low level time and the pressure working condition, wherein the zero current maintaining time after optimized distribution is a positive value or a zero value; during the off-excitation phase, an amplitude of-U is applied _Excitation And controlling the duration of the excitation negative voltage; in the phase of maintaining zero current, applying zero voltage; in the pre-excitation stage, the application amplitude is selected to be U according to the pre-excitation time and the expected pre-excitation current value _Excitation The pre-excitation voltage or amplitude range of the pre-excitation voltage or the amplitude range of the pre-excitation voltage is 0 to U _Excitation Pre-excitation voltage of;

4. The control method of the high-speed electromagnetic valve adapting to the working condition and the control parameter change according to claim 3, wherein the specific method for circularly controlling the high-speed electromagnetic valve in the continuous switching period comprises the following steps:

Step S2: setting high and low level switching signals with duty ratio g and period T, applying excitation high voltage to drive the valve plug to move and open when the rising edge of the high level of the switching signals arrives, and judging whether the valve plug moves to be completely opened or not by a characteristic point identification method based on real-time sampling current and derivative information thereof and current change trend;

and step S3: when the valve core is fully opened, recording the real-time t in the current period _{Characteristic point} Calculating to obtain the variable duty ratio value g of the high-frequency PWM voltage for maintaining the full opening of the valve core according to the current pressure working condition of the oil inlet and the differential pressure of the valve port _on (ii) a According to the control parameter g of the switch signal at the time _on And t _{Characteristic point} To obtain a variable frequency f of the high-frequency PWM voltage _on (ii) a Switching the excitation high voltage into high-frequency PWM voltage, and controlling the real-time current to maintain a high-frequency flutter mode at a full-opening current value, wherein the full-opening current value is the coil current required for maintaining the full opening of the valve core;

Step S6: when the zero voltage is completely applied, the zero voltage is switched to be U in amplitude _Excitation Pre-excitation voltage of t _{Pre-excitation} ＝t ₂ Controlling the real-time current to reach the expected pre-excitation current value I at the end of the current switching period _{Pre-excitation} Then jumping to step S1;

step S7: controlling the excitation negative voltage to reduce the current value to 0-I _off And recording the time t of the duration of the negative voltage excitation ₃ Obtaining a pre-excitation voltage having a duration of T × (1-g) -T ₃ ；

5. The method for controlling a high-speed electromagnetic valve adapting to the change of working conditions and control parameters according to claim 4, characterized in that when the valve core displacement moves to the maximum and the full opening is completed, a valve core full opening characteristic point occurs, and the current of the characteristic point is represented in a manner that the current rises from zero to a steady-state value U _Excitation /R _{Resistance value of coil} The lowest point of the curve with the curvature changing continuously is gradually decreased and then increased, and whether the valve core is fully opened or not is judged according to the current change condition of the characteristic point;

when the characteristic points are difficult to judge only through current change, identification judgment is carried out by combining current derivative information;

the method for identifying and judging the full-open characteristic points of the valve core comprises the following steps:

and step Q3: judging whether the current is in a rising stage and whether the real-time current reaches a critical starting current value, if so, turning to the next step, and otherwise, resetting the sampling counter again;

step Q4: selecting current values I of the first two sampling moments, the last sampling moment and the current sampling moment ₁ 、I ₂ 、I ₃ And a value of the derivative of the current I ₁ dot、I ₂ dot、I ₃ dot if I is satisfied ₁ >I ₂ And I ₂ <I ₃ Entering the next step; if the current information does not satisfy I ₁ >I ₂ And I is ₂ <I ₃ Screening and identifying the current derivative information to judge whether I is satisfied ₂ dot<I ₁ dot and I ₂ dot<I ₃ during dot, if the dot is satisfied, entering the next step, and if the dot is not satisfied, reselecting the sampling current and derivative information;

6. The method for controlling the high-speed electromagnetic valve adapting to the working condition and the control parameter change according to claim 4, wherein the method for acquiring the variable duty ratio and the variable frequency of the high-frequency PWM voltage adapting to the pressure working condition and the control parameter change by the switching signal comprises the following steps:

the variable duty cycle is:

wherein P is _s Is the pressure of the oil inlet, A is the area of action of the valve core, F _s1 Is a steady-state hydrodynamic force of the valve core in the full-open stage, F _s1 The numerical value of (D) is obtained by calculating the pressure difference between the oil inlet and the control port, mu ₀ Is air permeability, S is magnetic flux area, R _m1 Is the equivalent magnetic resistance when the valve core is fully opened, epsilon is the magnetic leakage coefficient, N is the number of turns, i _k Current compensation value, R, to maintain valve element fully open _{Resistance value of coil} Is the coil resistance value;

the variable frequency is:

f＝1/[(T×g-t _{characteristic point} )/(n+1/2+g _on /2)]

Wherein n and g × (T/T) _max ) Proportional ratio, T _max For the maximum period of the high-speed electromagnetic valve needing work, the real-time current is controlled by the variable frequency f to be just the high-frequency flutter current ripple at the moment of the action of the negative voltageAnd an intermediate value, wherein the intermediate value of the high-frequency flutter current ripple is the holding full-open current value.

7. The method for controlling the high-speed electromagnetic valve adapting to the working condition and the control parameter change according to claim 4, wherein the method for acquiring the time switching threshold value comprises the following steps:

8. The method for controlling the high-speed electromagnetic valve adapting to the working condition and the control parameter change according to claim 4, wherein the method for acquiring the expected pre-excitation current value under the real-time pressure working condition comprises the following steps:

calculating critical opening current I under real-time oil inlet pressure and real-time valve port pressure difference _on And critical off current I _off According to I _on The desired pre-excitation current value is obtained as follows:

I _{pre-excitation} ＝(U _Excitation -exp(R _{Coil resistance} ×t _delay /L _off )×(U _Excitation -I _on ×R _{Resistance value of coil} ))/R _{Resistance value of coil}

Wherein, I _{Pre-excitation} To obtain the desired pre-excitation current value, R _{Resistance value of coil} Is the coil resistance value, t _delay Selecting the preset optimal value of the starting electromagnetic delay time according to the starting electromagnetic delay time under the working condition of low pressure, L _off Is the equivalent inductance of the valve core closing stage.

9. The method for controlling a high-speed electromagnetic valve according to claim 8, wherein the amplitude value is 0-U according to the expected pre-excitation current value under the real-time pressure condition _Excitation The adaptive pre-excitation voltage is:

U _{pre-excitation} ＝((I _{Pre-excitation} -I _{Threshold value} )/(1-exp(-t _{Pre-excitation} ×R _{Resistance value of coil} /L _off ))+I _{Threshold value} )×R _{Resistance value of coil}

Wherein, I _{Threshold value} For closing the current threshold, the negative voltage is excited under the condition that the time switching threshold is less than zero to lead the coil current to fall to the lowest point, and the condition that 0 < I is satisfied _{Threshold value} ＜I _off Can follow I _off Is automatically adjusted by the change of t _{Pre-excitation} For a desired pre-excitation time, i.e. t _{Pre-excitation} ＝T×(1-g)-t ₃ 。