阅读说明：本技术 一种通过多电压源切换实现电磁阀各阶段动态特性可变的方法 (Method for realizing variable dynamic characteristics of electromagnetic valve at each stage by switching multiple voltage sources ) 是由 钟麒 李研彪 谢耿 王军 何贤剑 汪谢乐 孙造诣 于 2020-04-24 设计创作，主要内容包括：本发明公开了一种通过多电压源切换实现电磁阀各阶段动态特性可变的方法,属于电磁阀控制领域。本发明的控制方法分为若干阶段,通过控制高速切换开关接入不同电压源,使得高频电磁阀的启闭动态特性可以调节。本发明进一步公开了在电磁阀单周期持续时间较短情况下的电磁阀启闭特性调整方案,并给出了电磁阀的最慢启闭特性控制方法和最快启闭特性控制方法。本发明通过切换电压源使得高频电磁阀可满足使用者对高频电磁阀启闭动态特性的不同需求,大大拓宽了高频电磁阀工作范围。(The invention discloses a method for realizing variable dynamic characteristics of each stage of an electromagnetic valve through switching of multiple voltage sources, and belongs to the field of electromagnetic valve control. The control method of the invention is divided into a plurality of stages, and the dynamic opening and closing characteristics of the high-frequency electromagnetic valve can be adjusted by controlling the high-speed selector switch to be connected with different voltage sources. The invention further discloses an electromagnetic valve opening and closing characteristic adjusting scheme under the condition that the single-cycle duration of the electromagnetic valve is short, and provides a slowest opening and closing characteristic control method and a fastest opening and closing characteristic control method of the electromagnetic valve. According to the invention, the high-frequency electromagnetic valve can meet different requirements of users on the opening and closing dynamic characteristics of the high-frequency electromagnetic valve by switching the voltage source, and the working range of the high-frequency electromagnetic valve is greatly widened.)

1. A method for realizing variable dynamic characteristics of each stage of an electromagnetic valve by switching multiple voltage sources is characterized in that a coil of the electromagnetic valve is connected with a high-speed change-over switch through a current detector; each working port of the electromagnetic valve is connected with a pressure sensing system and used for acquiring the pressure state of each working port of the electromagnetic valve in real time; a displacement sensor is arranged in the electromagnetic valve and used for acquiring the motion state of a valve core of the electromagnetic valve; the high-speed change-over switch is provided with a first contact connected with the current detector and a plurality of voltage source contacts, and each voltage source contact is connected with a variable voltage source; the controller is connected with the high-speed change-over switch and can control the first contact to be connected with any voltage source contact; the controller is connected with the pressure sensing system to acquire data in the pressure sensing system in real time, and the controller is connected with the displacement sensor to acquire the time when the electromagnetic valve is completely opened and completely closed;

a working cycle of the electromagnetic valve is divided into 5 stages, the opening and closing characteristics of the electromagnetic valve are adjusted by controlling the output voltage value of the access variable voltage source of each stage of each cycle, and the method for adjusting the opening and closing characteristics of the electromagnetic valve in one cycle comprises the following steps:

1) initial stage of opening

Before the rising edge of the control signal comes, the controller triggers the high-speed change-over switch in advance to be connected with the variable voltage source at the stage, and under the action of the voltage source, the coil current reaches the starting initial current I₁Value | I of the turn-on initial current₁Is less than the value of the opening current I_{Is opened}|；

2) Opening phase

When the rising edge of the control signal comes, the controller triggers the high-speed change-over switch to be connected to the variable voltage source at the stage, the coil current rises under the action of the voltage source, and when the coil current reaches the starting current I_{Is opened}The electromagnetic valve starts to be opened, and the voltage continuously acts until the electromagnetic valve is completely opened; the method comprises the following steps that a displacement sensor (5) is triggered when the electromagnetic valve is completely opened, and the displacement sensor (5) acquires the time when the electromagnetic valve is completely opened and transmits the time to a controller;

3) initial stage of shutdown

When the electromagnetic valve is completely opened, the controller triggers the high-speed change-over switch to be connected to the variable voltage source at the stage, and the coil current is adjusted to be closed initial current I under the action of the voltage source₃(ii) a Value | I of the turn-off initial current₃| is greater than the closing current value | I_{Close off}|；

4) Closing phase

When the control signal falling edge comes, the controller triggers the high-speed change-over switch to be connected with the variable voltage source at the stage, the coil current falls under the action of the voltage source, and when the coil current falls to the closing current I_{Close off}When the electromagnetic valve is closed, the voltage source continuously acts until the electromagnetic valve is completely closed; triggering a displacement sensor (5) when the electromagnetic valve is completely closed, and transmitting the moment when the electromagnetic valve is completely closed to a controller by the displacement sensor (5);

5) shutdown maintenance phase

After the electromagnetic valve is completely closed, the displacement sensor transmits a signal to the controller, and the controller triggers the high-speed selector switch to be connected to the voltage source of the stage, wherein the voltage source of the stage is a zero voltage source, and the voltage source outputs zero voltage and the current is reduced to zero current under the action of the voltage source; until the next cycle.

2. The method of claim 1, wherein: the variable voltage source connected to each phase outputs a constant voltage value for the duration of the phase.

3. The method according to claim 1 or 2, wherein the variable voltage source connected to two or more different stages can be the same variable voltage source, and the output voltage values of the variable voltage source at different stages should meet the voltage control requirement of the stage.

4. The method of claim 1, wherein:

in the initial starting stage, the controller firstly controls the high-speed change-over switch to be connected into a voltage source, and under the action of the voltage source, the coil current value reaches the required initial starting current I₁(ii) a Then the high-speed change-over switch is controlled to be connected with a voltage value I_1*R voltage source or by changing the voltage value of the connected voltage source to I_1*R, keeping the coil current at the initial starting current I all the time₁Wherein R is the resistance of the solenoid valve coil;

in the other four stages, the voltage source connected in each stage outputs a constant current value within the duration of the stage.

5. The method of claim 1, wherein:

in the initial starting stage, the controller firstly controls the high-speed change-over switch to be connected into a voltage source, and under the action of the voltage source, the coil current value reaches the required initial starting current I₁(ii) a Then by controlling highThe value of the access voltage of the speed change-over switch is I_1*R voltage source or by changing the voltage value of the connected voltage source to I_1*R, keeping the coil current at the initial starting current I all the time₁Wherein R is the resistance of the solenoid valve coil;

in the initial stage of closing, the controller firstly controls the high-speed switch to be connected with a voltage source, and under the action of the voltage source, the current value of the coil reaches the required initial closing current I₃(ii) a Then the high-speed change-over switch is controlled to be connected with a voltage value I_3*R voltage source or by changing the voltage value of the connected voltage source to I_3*R, keeping the coil current at the initial starting current I all the time₃Wherein R is the resistance of the solenoid valve coil;

in the other three phases, the voltage source connected in each phase outputs a constant current value for the duration of the phase.

6. The method of claim 1, wherein the controller further comprises a control signal generating unit, wherein the control signal generating unit generates the control signal, and the controller is capable of knowing a duty cycle, a frequency, a rising edge time and a falling edge time of the control signal.

7. The method of claim 2, wherein: the opening or closing of the electromagnetic valve is not influenced by the current direction in the coil of the electromagnetic valve and is only related to the current value, so that one direction of the specified current is positive, and the other direction of the specified current is negative; the positive values of the current and the voltage indicate the same direction with the appointed direction, and the negative values indicate the opposite direction with the appointed direction; if the current solenoid valve is opened with a positive current value, then:

in the initial starting stage, the voltage value of the variable voltage source connected in the stage is increased, and the opening and closing dynamic characteristics of the electromagnetic valve can be improved; on the contrary, the voltage value of the variable voltage source is reduced, and the opening and closing dynamic characteristics of the electromagnetic valve can be reduced;

in the opening stage, the voltage value of the variable voltage source connected in the stage is increased, and the opening and closing dynamic characteristics of the electromagnetic valve can be improved; on the contrary, the voltage value of the variable voltage source is reduced, and the opening and closing dynamic characteristics of the electromagnetic valve can be reduced;

in the initial closing stage, the voltage value of the variable voltage source connected in the stage is reduced, and the opening and closing dynamic characteristics of the electromagnetic valve can be improved; on the contrary, the voltage value of the variable voltage source is increased, and the opening and closing dynamic characteristics of the electromagnetic valve can be reduced;

in the closing stage, the voltage value of the variable voltage source connected in the stage is reduced, and the opening and closing dynamic characteristics of the electromagnetic valve can be improved; on the contrary, the voltage value of the variable voltage source is increased, and the opening and closing dynamic characteristics of the electromagnetic valve can be reduced.

8. The method of claim 2, wherein: selecting the voltage value of the access voltage source of each stage to achieve the slowest on-off dynamic characteristic;

in the initial stage of starting, the voltage value of the variable voltage source selected to be connected meets the following conditions: 1) the voltage direction is opposite to the designated direction, 2) the voltage value is the maximum allowable starting initial voltage value | U_1maxThe maximum allowable starting voltage value is less than the starting voltage | U_{Is opened}The maximum value of the voltage values of l;

in the starting stage, the voltage value of the switched-in variable voltage source is selected to satisfy the following conditions: 1) the voltage direction is the same as the designated direction, 2) the voltage value is the minimum allowed turn-on voltage value, and the minimum allowed turn-on voltage value is larger than the turn-on voltage | U_{Is opened}The minimum of the voltage values of l;

in the initial stage of closing, selecting the voltage value of the accessed variable voltage source as the maximum forward voltage value in the adjustable range;

in the closing stage, the voltage value of the variable voltage source selected to be connected meets the following conditions: 1) the voltage direction is the same as the specified direction, 2) the voltage value is the maximum allowed turn-off voltage value, which is less than | U_{Close off}The maximum value of the voltage values of l.

9. The method of claim 2, wherein: selecting the voltage value of the access voltage source of each stage to enable the electromagnetic valve to achieve the fastest opening and closing dynamic characteristic;

in the initial stage of starting, the output voltage value of the selected accessed variable voltage source meets the following conditions: 1) the voltage direction is the same as the designated direction, 2) the voltage value is the maximum allowable starting initial voltage value | U_1maxThe maximum allowable starting voltage value is less than the starting voltage | U_{Is opened}The maximum value of the voltage values of l;

in the starting stage, selecting the voltage value of the accessed variable voltage source as the maximum forward voltage value in the adjustable range;

in the initial stage of closing, the output voltage value of the variable voltage source selected to be connected meets the following requirements: 1) the voltage direction is the same as the specified direction, 2) the voltage value is the minimum allowed turn-off initial voltage value | I_3minThe minimum allowable turn-off initial voltage value is greater than the turn-off voltage | U_{Close off}The minimum of the voltage values of l;

in the closing stage, the voltage value of the connected variable voltage source is selected as the reverse maximum voltage value in the adjustable range.

Technical Field

The invention belongs to the field of electromagnetic valve control, and particularly relates to a method for realizing variable dynamic characteristics of each stage of an electromagnetic valve through multi-voltage-source switching.

Background

In the field of existing high-frequency electromagnetic valves, most of the technologies aim at shortening the working period of the electromagnetic valve and improving the working frequency of the electromagnetic valve. Few technologies focus on how to realize the function of adjusting the opening and closing dynamic characteristics of the electromagnetic valve. The existing high-frequency electromagnetic valve has no function of adjusting the opening and closing dynamic characteristics, so that the working range of the existing high-frequency electromagnetic valve is limited.

In the opening stage of the electromagnetic valve, when the current value I is larger than the opening current, the electromagnetic valve starts to open; in the closing phase of the solenoid valve, the solenoid valve starts a closing movement when the current value | I | < closing current. When the electrical parameters (resistance, capacitance) in the electrical system are unchanged, the time for the current to rise to a certain value depends on the initial current and the magnitude of the driving voltage. The dynamic characteristic of opening and closing of the regulating electromagnetic valve can be started from two aspects of lag time and movement time of the regulating electromagnetic valve. Because the inductance effect of the solenoid valve coil is obvious in a high-frequency state, motion hysteresis occurs in the opening and closing stages of the solenoid valve in the prior art, namely, under the action of voltage, current lags due to the inductance effect and can rise to an expected current value after a period of time. The motion lag phenomenon can generate motion lag time, the motion lag time of the starting stage is related to the initial current of the starting stage, and the closer the initial current is to the starting current, the shorter the starting lag time is; the motion lag time of the closing phase is related to the initial current at the beginning of the closing phase, the closer this initial current is to the closing current, the shorter the motion lag time. The opening movement time and the closing movement time of the electromagnetic valve are related to the driving voltage in the opening stage and the driving voltage in the closing stage, and the larger the driving voltage is, the shorter the movement time is.

The adjustability of the lag time and the movement time of the high-frequency electromagnetic valve can realize the adjustability of the dynamic characteristic of the high-frequency electromagnetic valve, and has great practical significance.

Disclosure of Invention

In order to meet the requirements of the prior art and consider that the duty ratio of a voltage source needs to be changed in real time based on a voltage pulse width adjustment scheme so as to accurately output a voltage square wave corresponding to the duty ratio, and the control precision requirement is high, the invention provides a method for realizing variable dynamic characteristics of each stage of an electromagnetic valve through multi-voltage source switching.

The invention realizes the method that the dynamic characteristics of each stage of the electromagnetic valve can be changed by switching multiple voltage sources, and the coil of the electromagnetic valve is connected with the high-speed change-over switch through the current detector; each working port of the electromagnetic valve is connected with a pressure sensing system and used for acquiring the pressure state of each working port of the electromagnetic valve in real time; a displacement sensor is arranged in the electromagnetic valve and used for acquiring the motion state of a valve core of the electromagnetic valve; the high-speed change-over switch is provided with a first contact connected with the current detector and a plurality of voltage source contacts, and each voltage source contact is connected with a variable voltage source; the controller is connected with the high-speed change-over switch and can control the first contact to be connected with any voltage source contact; the controller is connected with the pressure sensing system to acquire data in the pressure sensing system in real time, and the controller is connected with the displacement sensor to acquire the time when the electromagnetic valve is completely opened and completely closed;

a working cycle of the electromagnetic valve is divided into 5 stages, the opening and closing characteristics of the electromagnetic valve are adjusted by controlling the output voltage value of the access variable voltage source of each stage of each cycle, and the method for adjusting the opening and closing characteristics of the electromagnetic valve in one cycle comprises the following steps:

1) initial stage of opening

Before the rising edge of the control signal comes, the controller triggers the high-speed change-over switch in advance to be connected with the variable voltage source at the stage, and under the action of the voltage source, the coil current reaches the starting initial current I₁Value | I of the turn-on initial current₁Is less than the value of the opening current I_{Is opened}|；

2) Opening phase

When the rising edge of the control signal comes, the controller triggers the high-speed change-over switch to be connected to the variable voltage source at the stage, the coil current rises under the action of the voltage source, and when the coil current reaches the starting current I_{Is opened}When the electromagnetic valve is opened, the voltage is continuously applied until the electromagnetic valve is completely opened(ii) a The method comprises the following steps that a displacement sensor (5) is triggered when the electromagnetic valve is completely opened, and the displacement sensor (5) acquires the time when the electromagnetic valve is completely opened and transmits the time to a controller;

3) initial stage of shutdown

When the electromagnetic valve is completely opened, the controller triggers the high-speed change-over switch to be connected to the variable voltage source at the stage, and the coil current is adjusted to be closed initial current I under the action of the voltage source₃(ii) a Value | I of the turn-off initial current₃| is greater than the closing current value | I_{Close off}|；

4) Closing phase

When the control signal falling edge comes, the controller triggers the high-speed change-over switch to be connected with the variable voltage source at the stage, the coil current falls under the action of the voltage source, and when the coil current falls to the closing current I_{Close off}When the electromagnetic valve is closed, the voltage source continuously acts until the electromagnetic valve is completely closed; triggering a displacement sensor (5) when the electromagnetic valve is completely closed, and transmitting the moment when the electromagnetic valve is completely closed to a controller by the displacement sensor (5);

5) shutdown maintenance phase

After the electromagnetic valve is completely closed, the displacement sensor transmits a signal to the controller, and the controller triggers the high-speed selector switch to be connected to the voltage source of the stage, wherein the voltage source of the stage is a zero voltage source, and the voltage source outputs zero voltage and the current is reduced to zero current under the action of the voltage source; until the next cycle.

As the method for adjusting the opening and closing characteristics of the selectable electromagnetic valve, the variable voltage source connected into each stage outputs a constant voltage value within the duration of the stage.

In a preferred embodiment of the present invention, the variable voltage source connected to two or more different stages may be the same variable voltage source, but as a multi-stage shared variable voltage source, the output voltage values of the variable voltage source at different stages should meet the voltage control requirement of the stage. Preferably, an independent variable voltage source is correspondingly connected to each stage. Therefore, the access of the voltage source is completely realized by the high-speed change-over switch in the period of the whole electromagnetic valve, and one voltage source can meet the use requirements of multiple stages without adjusting the output voltage value of the variable voltage source.

As the method for adjusting the opening and closing characteristics of the selectable electromagnetic valve, the controller firstly controls the high-speed change-over switch to be connected into the voltage source in the initial opening stage, and the coil current value reaches the initial opening current I required under the action of the voltage source₁(ii) a Then the high-speed change-over switch is controlled to be connected with a voltage value I₁Voltage source of R or by changing the value of the voltage of the connected voltage source to I₁R, keeping the coil current at the initial starting current I₁Wherein R is the resistance of the solenoid valve coil;

in the other four stages, the voltage source connected in each stage outputs a constant current value within the duration of the stage.

As the method for adjusting the opening and closing characteristics of the selectable electromagnetic valve, the controller firstly controls the high-speed change-over switch to be connected into the voltage source in the initial opening stage, and the coil current value reaches the initial opening current I required under the action of the voltage source₁(ii) a Then the high-speed change-over switch is controlled to be connected with a voltage value I₁Voltage source of R or by changing the value of the voltage of the connected voltage source to I₁R, keeping the coil current at the initial starting current I₁Wherein R is the resistance of the solenoid valve coil;

in the initial stage of closing, the controller firstly controls the high-speed switch to be connected with a voltage source, and under the action of the voltage source, the current value of the coil reaches the required initial closing current I₃(ii) a Then the high-speed change-over switch is controlled to be connected with a voltage value I₃Voltage source of R or by changing the value of the voltage of the connected voltage source to I₃R, keeping the coil current at the initial starting current I₃Wherein R is the resistance of the solenoid valve coil;

in the other three phases, the voltage source connected in each phase outputs a constant current value for the duration of the phase.

As a preferred embodiment of the present invention, the controller further includes a control signal generating unit, the control signal generating unit generates the control signal, and the controller can obtain a duty ratio, a frequency, a rising edge time and a falling edge time of the control signal.

As a preferable aspect of the present invention, since the opening or closing of the solenoid valve is not affected by the direction of current in the solenoid valve coil, and is only related to the current value, one direction of the specified current is positive, and the other direction is negative; the positive values of the current and the voltage indicate the same direction with the appointed direction, and the negative values indicate the opposite direction with the appointed direction; if the current solenoid valve is opened with a positive current value, then:

in the initial starting stage, the voltage value of the variable voltage source connected in the stage is increased, and the opening and closing dynamic characteristics of the electromagnetic valve can be improved; on the contrary, the voltage value of the variable voltage source is reduced, and the opening and closing dynamic characteristics of the electromagnetic valve can be reduced;

in the opening stage, the voltage value of the variable voltage source connected in the stage is increased, and the opening and closing dynamic characteristics of the electromagnetic valve can be improved; on the contrary, the voltage value of the variable voltage source is reduced, and the opening and closing dynamic characteristics of the electromagnetic valve can be reduced;

in the initial closing stage, the voltage value of the variable voltage source connected in the stage is reduced, and the opening and closing dynamic characteristics of the electromagnetic valve can be improved; on the contrary, the voltage value of the variable voltage source is increased, and the opening and closing dynamic characteristics of the electromagnetic valve can be reduced;

in the closing stage, the voltage value of the variable voltage source connected in the stage is reduced, and the opening and closing dynamic characteristics of the electromagnetic valve can be improved; on the contrary, the voltage value of the variable voltage source is increased, and the opening and closing dynamic characteristics of the electromagnetic valve can be reduced.

As the preferred scheme of the invention, the voltage value of the access voltage source of each stage is selected to achieve the slowest on-off dynamic characteristic;

in the initial stage of starting, the voltage value of the variable voltage source selected to be connected meets the following conditions: 1) the voltage direction is opposite to the designated direction, 2) the voltage value is the maximum allowable starting initial voltage value | U_1maxThe maximum allowable starting voltage value is less than the starting voltage | U_{Is opened}The maximum value of the voltage values of l;

in the starting stage, the voltage value of the switched-in variable voltage source is selected to satisfy the following conditions: 1) direction of voltageSame as the specified direction, 2) the voltage value is the minimum allowed turn-on voltage value, which is the achievable value greater than the turn-on voltage | U_{Is opened}The minimum of the voltage values of l;

in the initial stage of closing, selecting the voltage value of the accessed variable voltage source as the maximum forward voltage value in the adjustable range;

in the closing stage, the voltage value of the variable voltage source selected to be connected meets the following conditions: 1) the voltage direction is the same as the specified direction, 2) the voltage value is the maximum allowed turn-off voltage value, which is less than | U_{Close off}The maximum value of the voltage values of l.

As the preferred scheme of the invention, the voltage value of the access voltage source of each stage is selected to enable the electromagnetic valve to achieve the fastest opening and closing dynamic characteristic;

in the initial stage of starting, the output voltage value of the selected accessed variable voltage source meets the following conditions: 1) the voltage direction is the same as the designated direction, 2) the voltage value is the maximum allowable starting initial voltage value | U_1maxThe maximum allowable starting voltage value is less than the starting voltage | U_{Is opened}The maximum value of the voltage values of l;

in the starting stage, selecting the voltage value of the accessed variable voltage source as the maximum forward voltage value in the adjustable range;

in the initial stage of closing, the output voltage value of the variable voltage source selected to be connected meets the following requirements: 1) the voltage direction is the same as the specified direction, 2) the voltage value is the minimum allowed turn-off initial voltage value | I_3minThe minimum allowable turn-off initial voltage value is greater than the turn-off voltage | U_{Close off}The minimum of the voltage values of l;

in the closing stage, the voltage value of the connected variable voltage source is selected as the reverse maximum voltage value in the adjustable range.

According to the invention, the working cycle of a single electromagnetic valve is divided into 5 stages, so that the electromagnetic valve can respond to the opening and closing actions of the electromagnetic valve according to the switching signal, and the most basic working requirements of the electromagnetic valve are met; secondly, the opening and closing characteristics of the electromagnetic valve can be adjusted through a high-speed change-over switch, and the electromagnetic valve is simple in hardware system and high in reliability. In addition, the output voltage of the power source accessed at each stage is independently adjustable, so that different opening characteristic adjustment and closing characteristic adjustment can be achieved according to requirements, and various requirements of the control working condition on the opening and closing characteristics are met; and the output voltage of the same stage under different periods can be adjusted, thereby greatly widening the working range of the high-frequency electromagnetic valve.

Finally, aiming at the requirement of higher frequency, the invention further optimizes the initial starting stage and/or the initial closing stage on the premise of dividing the working period into 5 stages, adds a current maintaining stage in the corresponding stage and shortens the time ratio of the current adjusting process in the whole period, thereby ensuring that the electromagnetic valve can meet the requirement of users on adjustable opening and closing characteristics even facing to the working environment of higher frequency.

Drawings

FIG. 1 is a schematic diagram of a system configuration corresponding to the 5-stage scheme in the example;

FIG. 2 is a schematic diagram of a system architecture corresponding to the 6-stage scheme in the example;

FIG. 3 is a schematic diagram of the system architecture corresponding to the 7-stage scheme in the example;

FIG. 4 is a graph of control signals and current for a 5-phase scheme of the present invention;

FIG. 5 is a graph of control signals and current for a 6-phase scheme of the present invention;

FIG. 6 is a graph of the control signals and current for a 7-phase scheme of the present invention;

FIG. 7 is a graph comparing the fastest and slowest dynamics of the solenoid during the opening phase;

FIG. 8 is a graph comparing fastest and slowest dynamics of a solenoid valve during a closing phase.

Detailed Description

The invention will be further illustrated and described with reference to specific embodiments. The technical features of the embodiments of the present invention can be combined correspondingly without mutual conflict.

Hardware system

As shown in fig. 1, the optional hardware system of the present invention may include four variable voltage sources 1-4, a zero voltage source 5 (the zero voltage source may be understood as a variable voltage source whose output is always 0 voltage), a high-speed switch 6 (including a first contact 6-0 and 5 voltage source contacts 6-1 to 6-5, where the 5 voltage source contacts are respectively connected to the 4 variable voltage sources and the zero voltage source), a current detector 7, an electromagnetic valve 8, a pressure sensing system 10, a displacement sensor 9, and a controller 11;

a coil of the electromagnetic valve is connected with the high-speed change-over switch through a current detector; each working port of the electromagnetic valve is connected with a pressure sensing system and used for acquiring the pressure state of each working port of the electromagnetic valve in real time; a displacement sensor is arranged in the electromagnetic valve and used for acquiring the motion state of a valve core of the electromagnetic valve; the first contact of the high-speed change-over switch is connected with the current detector; the controller is connected with the high-speed change-over switch and can control the first contact to be connected with any voltage source contact; the controller is connected with the pressure sensing system to acquire data in the pressure sensing system in real time, and the controller is connected with the displacement sensor to acquire the time when the electromagnetic valve is completely opened and completely closed.

The displacement sensor adopts a linear displacement sensor, and the linear displacement sensor has the function of converting linear mechanical displacement into an electric signal.

The pressure sensing system in this embodiment is connected to the solenoid valve, thereby obtaining the pressure state of each working port of the solenoid valve in real time. The displacement sensor is connected with the solenoid valve, so that the motion state of the solenoid valve is obtained, and the time when the solenoid valve is fully opened and fully closed is obtained. The controller is connected with the pressure sensing system and comprises a control signal generating unit. A rising edge of the control signal indicates that an operator desires the solenoid valve to be opened, a high potential of the control signal indicates that the operator desires the solenoid valve to be in an open state, a falling edge of the control signal indicates that the operator desires the solenoid valve to be closed, and a low potential of the control signal indicates that the operator desires the solenoid valve to be in a closed state.

And the controller acquires data in the pressure sensing system in real time so as to calculate the system opening current and the system closing current in the current state. The controller generates a control signal, namely the control signal is generated by the controller and participates in the operations such as internal calculation, digital triggering and the like of the controller. The controller obtains data in the displacement sensor in real time, namely the time when the electromagnetic valve is completely opened and closed.

For ease of illustration, the control signal 12 is drawn outside of the controller in FIG. 1. The control signal is a square wave with adjustable frequency and duty ratio. Because the control signal is generated by the controller, the controller can also know the duty ratio, the frequency, the rising edge time and the falling edge time of the control signal in different states and know when the rising edge of the control signal in the next period comes.

Preferably, the output voltage ranges of all the variable voltage sources are the same, and in this embodiment, the output ranges of all the variable voltages are-24V to 24V, that is, the maximum output voltage value is 24V.

As shown in fig. 2 and 3, the number of variable voltage sources is increased in fig. 2 and 3 compared to the system shown in fig. 1, while the number of voltage source contacts of the high speed switcher is correspondingly increased. The schemes of fig. 2 and 3 correspond to 6-phase and 7-phase schemes, respectively, i.e. each phase is assigned an independent variable voltage source. Therefore, the access of the voltage source is completely realized by the high-speed change-over switch in the period of the whole electromagnetic valve, and one voltage source can meet the use requirements of multiple stages without adjusting the output voltage value of the variable voltage source.

Of course, the variable voltage source connected in two or more different stages may also be the same variable voltage source, but as a multi-stage shared variable voltage source, the output voltage values of the variable voltage source in different stages should meet the voltage control requirement of the stage. For example, in the scheme shown in fig. 1, the variable voltage source 4 and the zero voltage source 5 may be combined into one variable voltage source a (i.e., one variable voltage source is shared by the shutdown phase and the shutdown maintenance phase), in the scheme shown in fig. 1, when it is required to access the variable voltage source 4 and the zero voltage source 5, the high-speed switch is selected to access the variable voltage source a, but the output of the variable voltage source a needs to be adjusted in different phases, for example, the variable voltage source a needs to output zero voltage (acting as a zero voltage source) in the shutdown maintenance phase to ensure the control requirement of the corresponding phase.

Second, electromagnetic valve opening and closing characteristic adjusting method

The method for adjusting the opening and closing characteristics of the electromagnetic valve based on voltage source switching changes the opening and closing dynamic characteristics of the electromagnetic valve according to the movement lag time of the electromagnetic valve during opening and closing and the working movement time of the electromagnetic valve during opening and closing. The slowest opening and closing characteristic scheme and the fastest opening and closing characteristic scheme under the corresponding adjusting method of the invention are described below. In actual work, the opening and closing characteristics can be adjusted between the slowest opening and closing characteristic scheme and the fastest opening and closing characteristic scheme through the control of the voltage source in each stage according to the requirement on the opening and closing characteristics.

The method for adjusting the opening and closing characteristics of the electromagnetic valve, which is the most basic method of the invention, divides the working cycle of the electromagnetic valve into five stages: the first stage is an initial starting stage, the second stage is an initial starting stage, the third stage is an initial closing stage, the fourth stage is a closing stage, and the fifth stage is a closing maintaining stage.

The opening or closing of the electromagnetic valve is not influenced by the current direction in the coil of the electromagnetic valve and is only related to the current value, so that one direction of the specified current is positive, and the other direction of the specified current is negative; the positive values of the current and the voltage indicate the same direction as the designated direction, and the negative values indicate the opposite direction to the designated direction.

Scheme 1

As shown in fig. 1 and the left diagram of fig. 4, assuming that the solenoid valve is turned on with a positive current value (when turned on with a negative current value, the principle and process are exactly the same as those with a positive current value, and only the voltage and the current need to take opposite signs), the steps of the control method adopted for the solenoid valve to reach the slowest dynamic characteristic include the following steps:

1) initial stage of opening

Before the rising edge of the control signal comes, the controller calculates the time for the current to rise from the current state to the initial starting current under the action of the initial starting voltage according to the current coil electrical parameters and the data obtained from the pressure sensor, and for the feasibility of the control method, the time can be generally prolonged by 5% -10% on the basis of the time, and the time is taken as the time of the first stage. The rising edge arrival time of the control signal is the end time of the first stage, the controller can obtain the start time of the first stage according to the calculated duration of the first stage, at the start time, the controller controls the high-speed change-over switch to be connected into the variable voltage source 1, the variable voltage source 1 outputs a negative maximum allowable starting initial voltage value, the value is a negative starting voltage beta, wherein beta represents the control precision of a hardware system, and beta can be generally 0.90-0.95 in order to stably output the maximum allowable starting initial voltage value and ensure that the electromagnetic valve is not opened under the action of the pulse voltage; negative turn-on voltage is the negative starting current coil resistance. I.e. the initial voltage direction is negative. Under the action of the voltage, the current is reduced to a negative maximum allowable starting initial current value.

2) Opening phase

When the rising edge of the control signal comes, the second stage is entered. The controller controls the high-speed switch to be connected into the variable voltage source 2, and the variable voltage source 2 outputs a minimum allowable starting voltage value, wherein the minimum allowable starting voltage value can be 1.05-1.1 times of the starting voltage value generally. Under the action of the voltage, the current of the coil rises to the current at the opening stage, the current at the opening stage is slightly larger than the opening current (the opening current is the coil resistance is the opening voltage), the electromagnetic valve starts to be opened at the moment, the current finally makes high-frequency small fluctuation around the opening current value, and the voltage at the opening stage is continued until the electromagnetic valve is completely opened; triggering a displacement sensor when the electromagnetic valve is completely opened, and acquiring the time when the electromagnetic valve is completely opened by the displacement sensor;

wherein, the lag time T of the starting motion is from the rising edge time of the control signal to the time when the coil current reaches the starting current_a(ii) a The moment from the moment when the coil current reaches the opening current to the moment when the electromagnetic valve is completely opened is the opening movement time T_b；

3) Initial stage of shutdown

When the electromagnetic valve is completely opened, the displacement sensor is triggered, the displacement sensor transmits a signal to the controller, the controller controls the high-speed selector switch to be connected to the variable voltage source 3, and the variable voltage source 3 outputs a positive maximum voltage value. Under the action of the voltage, the current of the coil rises to the maximum forward current value, and the current is maintained at the closing initial current until the falling edge of the control signal comes;

4) closing phase

When the control signal falling edge comes, the fourth stage is entered, the controller controls the high-speed switch to be connected to the variable voltage source 4, the variable voltage source 4 outputs the maximum allowable closing voltage, and the maximum allowable closing voltage can generally take the closing voltage value of 0.90-0.95 times. Under the action of the voltage, the coil current is reduced to a value slightly smaller than a closing current (smaller than 5% -10% of the closing current), when the coil current is reduced to the closing current, the electromagnetic valve starts to be closed, and the voltage in the closing stage is continued until the electromagnetic valve is completely closed; triggering a displacement sensor (4) when the electromagnetic valve is completely closed, wherein the displacement sensor (4) acquires the time when the electromagnetic valve is completely closed;

wherein, the lag time T of the closing movement is from the falling edge time of the control signal to the time when the coil current reaches the closing current_c(ii) a The time from the moment when the coil current reaches the closing current to the moment when the solenoid valve is completely closed is the closing movement time T_d；

5) Shutdown maintenance phase

When the electromagnetic valve is completely closed, the displacement sensor transmits a signal to the controller, the fifth stage is started, the controller controls the high-speed selector switch to be connected to the zero voltage source 5, and the zero voltage source 5 starts to output zero voltage. The current drops to zero current. Until the next cycle, the system repeats the above steps.

In the control scheme, the initial opening current in the first stage is the maximum negative current value capable of ensuring that the electromagnetic valve is in a closed state, so that the maximum span of the coil current rising from the initial opening current to the forward opening current in the second stage is ensured; the driving voltage in the second stage is the turn-on stage voltage, which has a value slightly greater than the turn-on voltage value and is the minimum voltage value that can ensure that the current rises to the turn-on current, which minimizes the rate at which the current rises from the turn-on initial current to the turn-on current. The combination of the two points makes the time for the current to rise from the initial starting current to the starting current longest, namely the time of starting motion lagInter (T)_a) The longest.

In the second stage, the opening voltage is a critical value for opening the electromagnetic valve. Below this voltage, the current does not rise to the opening current, the electromagnetic force cannot overcome the resistance, and the solenoid valve cannot be opened. Therefore, when the voltage in the opening stage is slightly larger than the opening voltage, the current can reach the opening current, the electromagnetic force is larger than the resistance, the electromagnetic valve can be opened, and the electromagnetic valve can be opened in the longest time, namely the opening motion time (T)_b) The longest.

The driving voltage of the third stage is the closing initial voltage, and the maximum forward voltage value is accessed to ensure that the closing initial current rises to the maximum value. This ensures that the span from the off-initial current to the off-current in the fourth phase is maximized; the drive voltage in the fourth phase is the off-phase voltage, which is the maximum voltage value that ensures that the current can drop below the off-current, which minimizes the rate at which the current drops from the off-initial current to the off-current. The combination of the two points makes the time for the current to decrease from the initial closing current to the closing current to be the longest, namely the closing motion lag time (T)_c) The longest.

When the electromagnetic valve is closed, the electromagnetic force generated by the electromagnetic valve is the resistance of the closing movement, and the larger the driving voltage is, the larger the resistance of the closing movement of the electromagnetic valve is, and the longer the closing movement time is. The closing voltage is a critical value for whether the electromagnetic valve can be closed, when the voltage value is larger than the closing voltage value, the current cannot fall below the closing current, the electromagnetic force is larger than the resistance, and the electromagnetic valve cannot be closed. When the voltage value is slightly less than the closing voltage value in the closing stage, the current of the coil can be ensured to be reduced below the closing current, the electromagnetic force is less than the resistance, the electromagnetic valve can be closed, the resultant force received in the closing process of the electromagnetic valve can be ensured to be minimum, and the closing movement time (T) is shortened_d) The longest.

Scheme 2

When the solenoid valve operates at a high frequency, the duration of a single period is short, and at this time, the scheme shown in the left diagram of fig. 4 may not meet the high frequency requirement due to the long duration of each current adjusting process. At this time, the start-up initial stage can be divided into two sub-stages, i.e. a start-up initial current generation stage and a start-up initial current maintenance stage, based on the slowest control scheme shown in the left diagram of fig. 4. The whole scheme 2 is equivalent to 6 stages, as shown in the left diagram of fig. 5, and the corresponding hardware system can be selected as shown in fig. 2.

The design idea is that a voltage source with a larger output voltage value than that of the left graph of FIG. 4 is selected to achieve the starting initial current; and then, in the initial current starting maintaining stage, the connected voltage source is changed or adjusted to continuously maintain the initial current starting. The time of the initial starting current maintaining stage can be adjusted according to requirements, and can even be shortened to be close to 0 under the limit condition, so that the required time of the whole initial starting stage is shortened compared with the scheme of the left diagram of fig. 4, and the high-frequency requirement can be better met. It should be noted that, since the opening initial current (negative maximum allowable opening initial current value) and the current to be achieved at other stages are not changed, the opening and closing dynamics of the schemes shown in the left diagrams of fig. 4 and 5 are identical.

Since the other stages of the scheme of the left diagram of fig. 4 are the same as those of the left diagram of fig. 5, only the initial starting stage under the slowest opening and closing characteristic shown in the left diagram of fig. 5 is described as follows:

taking the system of FIG. 2 as an example, in the initial stage of starting, first, the controller controls the high-speed switch to access the variable voltage source 1-1, the variable voltage source 1-1 outputs the reverse maximum voltage value, under the action of the voltage, the current rapidly drops to the negative maximum allowable starting initial current value-I_1max(it may be 90% to 95% of the negative turn-on current (negative turn-on current: coil resistance ═ negative turn-on voltage)). In this process, since the drive voltage is known and the target current is known, the duration is calculable from the coil parameters of the solenoid valve.

Then, the variable voltage source 1-2 is connected in by controlling the high-speed change-over switch, and the output voltage value of the variable voltage source 1-2 is-I_1maxR (also by changing the voltage value of the connected variable voltage source 1-1 to-I_1maxR, without the need of a variable voltage source 1-2), the coil current is always maintained at a negative maximum allowed starting initial current-I_1maxWherein R is solenoid valve coil electricityBlocking; since the maximum allowable opening initial current value is known, the output voltage value of the variable voltage source 2 is obtained according to the coil parameter of the electromagnetic valve.

The left diagram of fig. 6 shows a scheme for further shortening the time taken for the initial stage of shutdown, which is based on the idea that in the initial current generation stage of shutdown, a voltage larger than the value (absolute value) of the left diagram of fig. 5 is selected to reach the initial current of shutdown at a faster speed; and then, in the initial current closing maintaining stage, the access voltage is adjusted to continuously maintain the initial current closing. The time for turning off the initial current maintaining stage can be adjusted according to the requirement, and can even be shortened to 0 under the limit condition. Since the scheme shown in the left diagram of fig. 5 already adopts the maximum output voltage value at the initial stage of shutdown, the scheme shown in the left diagram of fig. 6 is the same as the scheme shown in the left diagram of fig. 5.

2.1 fastest opening and closing characteristic scheme

Scheme 1

As shown in fig. 1 and fig. 4, the steps of the control method adopted when the current solenoid valve is opened at a positive current value and the solenoid valve reaches the fastest period include the following steps:

1) initial stage of opening

Before the rising edge of the control signal comes, the controller calculates the time for the current to rise from the zero state to the initial starting current under the action of the initial starting voltage according to the current electrical parameters of the coil and the data obtained from the pressure sensor, and in order to stabilize and enable the control method, the time can be generally prolonged by 5% -10% on the basis of the time, and the time is taken as the time of the first stage. The rising edge arrival time of the control signal is the end time of the first phase. Before the rising edge of the control signal comes, the controller controls the high-speed change-over switch to be switched in the variable voltage source 1 according to the calculated duration of the first stage, the variable voltage source 1 outputs a maximum allowable starting initial voltage value, which is the starting voltage beta, wherein beta represents the control precision of a hardware system, and beta is generally 0.90-0.95 in order to stably output the maximum allowable starting initial voltage value and ensure that the electromagnetic valve is not opened under the action of the pulse voltage; turn-on voltage-start current-coil resistance. Under the action of the voltage, the current rises to turn on the initial current.

2) Opening phase

When the rising edge of the control signal comes, the second stage is entered. The controller controls the high-speed change-over switch to be connected into the variable voltage source 2, the variable voltage source 2 outputs the forward maximum voltage, the coil current is adjusted to rise to the opening current under the action of the voltage, the electromagnetic valve starts to be opened at the moment, and the voltage is continuously maintained in the opening stage until the electromagnetic valve is completely opened; triggering a displacement sensor when the electromagnetic valve is completely opened, and acquiring the time when the electromagnetic valve is completely opened by the displacement sensor;

3) initial stage of shutdown

When the solenoid valve is fully open, the third phase is entered. The controller controls the high-speed switch to be connected to the variable voltage source 3, the variable voltage source 3 outputs a minimum allowed closing initial voltage, the minimum allowed closing initial voltage is a closing voltage which is generally 1.05-1.10 times, and the minimum allowed closing initial voltage is a minimum voltage value which can be reached by ensuring that the current cannot drop to the closing current. The coil current drops to a minimum allowed off initial current (which is slightly greater than the off current) under a minimum allowed off initial voltage. This voltage continues until the falling edge of the control signal arrives. The duration of the third phase is the time interval between the end of the second phase and the arrival of the falling edge of the control signal.

4) Closing phase

When the falling edge of the control signal comes, the fourth stage is entered, the controller controls the high-speed change-over switch to be connected to the variable voltage source 4, and the variable voltage source 4 outputs the reverse maximum voltage value. At which the coil current drops rapidly to the closing current and continues to drop to zero. When the coil current is less than the closing current, the solenoid valve begins a closing motion. Since the current in the third phase has already reached the switch-off initial current, which is slightly larger than the switch-off current, the current will drop to the switch-off current in a very short time, i.e. the switch-off movement lag time is very short. The solenoid valve is fully closed under the fourth stage voltage. The duration of the fourth phase is equal to the time interval from the end of the third phase to the moment of complete closure of the solenoid valve.

5) Shutdown maintenance phase

When the electromagnetic valve is completely closed, the displacement sensor transmits a signal to the controller, the fifth stage is started, the controller controls the high-speed selector switch to be connected to the zero voltage source 5, and the zero voltage source 5 starts to output zero voltage. The current drops to zero current. Until the next cycle, the system repeats the above steps.

In the fastest control strategy, the current in the first stage reaches the starting initial current, namely is slightly smaller than the starting current, so that the minimum span from the starting initial current to the starting current is ensured. The second stage drive voltage is a turn-on drive voltage, which is a forward maximum voltage value. Under the voltage drive of the starting stage of the second stage, the shortest time of the coil current rising from the starting initial current to the starting current, namely the shortest starting motion lag time (T)_a"). Simultaneously, the method also ensures that the current of the coil increases fastest in the opening motion of the electromagnetic valve, namely the electromagnetic force increases fastest, and ensures the opening motion time (T) of the electromagnetic valve_bMin).

The driving voltage of the third stage is slightly larger than the closing voltage, so that the closing initial current is ensured to be slightly larger than the closing current and is the minimum value which can be reached. This ensures that the time for the coil current to drop from the off-initial current to the off-current in the negative maximum voltage of the fourth phase is minimized, i.e. the off-movement lag time (T)_cMin).

The driving voltage in the fourth stage is the off-stage voltage, which is the maximum negative voltage value. In the closing movement of the electromagnetic valve, the electromagnetic force is resistance, and the maximum negative voltage can ensure that the current of the coil reaches zero at the fastest speed, so that the descending speed of the electromagnetic force is the fastest, and the resultant force in the closing movement reaches the maximum value. Thereby ensuring the closing movement time (T) of the electromagnetic valve_dMin).

Different driving voltages are adopted at different stages through the high-frequency switch voltage, so that the opening and closing dynamic characteristics of the high-frequency electromagnetic valve can be adjusted. The adjustment enables the high-frequency electromagnetic valve to meet different requirements of users on the opening and closing dynamic characteristics of the high-frequency electromagnetic valve. The working range of the high-frequency electromagnetic valve is greatly widened.

Scheme 2

When the solenoid valve operates at a high frequency, the duration of a single period is short, and at this time, the scheme shown in the right diagram of fig. 4 may not meet the high frequency requirement due to the long duration of each current adjusting process. At this time, on the basis of the fastest control scheme shown in the right diagram of fig. 4, the initial starting stage is divided into two sub-stages, namely, an initial starting current generation stage and an initial starting current maintaining stage, and a voltage with a larger value than that of the right diagram of fig. 4 is selected in the initial starting current generation stage to reach the initial starting current at a faster speed; and then in the initial current sustaining stage of starting. The whole scheme 2 is equivalent to 6 stages. The switching dynamics of the solutions shown in the right diagram of fig. 2 and the right diagram of fig. 3 are identical, since the starting initial current (maximum permissible starting initial current value) and the current to be reached at other stages are unchanged.

Since other stages of the scheme of the right diagram of fig. 5 are consistent with the right diagram of fig. 4, only the initial starting stage under the fastest opening and closing characteristic shown in the right diagram of fig. 5 is described as follows:

with the system shown in FIG. 2, at the initial stage of starting, the controller controls the high-speed switch to switch in the variable voltage source 1-1, the variable voltage source 1-1 outputs the maximum forward voltage, and the current rapidly rises to the maximum allowable starting initial current value I under the action of the voltage_1max(it may be 90% to 95% of the turn-on current (turn-on current: coil resistance ═ turn-on voltage)). In this process, since the drive voltage is known and the target current is known, the duration is calculable from the coil parameters of the solenoid valve.

Then, the variable voltage source 1-2 is connected in by controlling the high-speed switch, and the output voltage value of the variable voltage source 1-2 is I_1maxR (also by changing the voltage value-I of the switched-in variable voltage source 1-1_1maxR) to maintain the coil current always at a negative maximum allowed turn-on initial current I_1maxWherein R is the resistance of the solenoid valve coil; since the maximum allowable opening initial current value is known, the output voltage value of the variable voltage source 1-2 isCan be obtained.

Scheme 3

When the solenoid valve operates at a higher frequency, the duration of a single cycle will be shorter, and the schemes shown in the right diagram of fig. 4 and the right diagram of fig. 5 may not meet the high frequency requirement. At this time, on the basis of the slowest control scheme shown in the right diagram of fig. 5, the initial shutdown stage may be divided into two sub-stages, that is, an initial shutdown current generation stage and an initial shutdown current maintenance stage, and in the initial shutdown current generation stage, a voltage output having a larger value (absolute value) than that of the right diagram of fig. 5 is selected to reach the initial shutdown current at a faster speed; and then, in the initial current closing maintaining stage, the access voltage value is adjusted to continuously maintain the initial current closing. The whole protocol 3 corresponds to 7 stages. The opening and closing dynamics of the solution shown in the right diagram of fig. 4 and 6 are exactly the same.

Since the other stages of the scheme of the right diagram of fig. 6 are consistent with the right diagram of fig. 5 (the fastest opening and closing characteristic scheme 2), only the initial closing stage under the fastest opening and closing characteristic shown in the right diagram of fig. 6 is described as follows:

with the system shown in FIG. 3, in the initial stage of shutdown, first, the controller controls the high-speed switch to switch in the variable voltage source 3-1, the variable voltage source 3-1 outputs the maximum reverse voltage, and under the action of the voltage, the current rapidly drops to the minimum allowable shutdown initial current value I_3min(it can be taken as 105% to 110% of the off current). In this process, since the drive voltage is known and the target current is known, the duration is calculable from the coil parameters of the solenoid valve.

Then, the variable voltage source 3-2 is connected in by controlling the high-speed switch, and the output voltage value of the variable voltage source 3-2 is I_3minR (also by changing the voltage value I of the switched-in variable voltage source 3-1_3minR) to maintain the coil current at a negative minimum allowed off-initial current value I at all times_3minWherein R is the resistance of the solenoid valve coil; since the maximum allowable opening initial current value is known, the output voltage value of the variable voltage source 3-2 is obtained according to the coil parameter of the electromagnetic valve.

Opening and closing dynamic characteristic adjustment of electromagnetic valve in the inventionThe pitch range is (T)_a+T_b+T_c+T_d) To (T)_a＇+T_b＇+T_c＇+T_d＇)。

As can be seen in fig. 7, the opening lag time and the opening movement time (T) in the fastest opening and closing dynamics during the solenoid valve opening phase_a’、T_b’) Both of which are far shorter than the opening hysteresis time and the opening movement time (T) in the slowest opening and closing dynamic characteristic_a、T_b)。

As can be seen in FIG. 8, the closing lag time in the fastest opening and closing dynamics (T) is the closing movement time during the solenoid closing phase_c’、T_d’) Both of which are far shorter than the closing hysteresis time and closing movement time (T) in the slowest opening and closing dynamics_c、T_d)。

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.