Method for realizing motion controllability of valve core of high-speed switch valve based on speed controller
阅读说明：本技术 一种基于速度控制器实现高速开关阀阀芯运动可控的方法 (Method for realizing motion controllability of valve core of high-speed switch valve based on speed controller ) 是由 钟麒 汪谢乐 谢耿 王军 何贤剑 李研彪 于 2020-06-01 设计创作，主要内容包括：本发明公开了一种基于速度控制器实现高速开关阀阀芯运动可控的方法,属于高速开关阀控制领域。将高速开关阀的一个工作周期分为多个阶段,通过控制每个周期各阶段的占空比,使电压源输出相应占空比的电压方波,进行高速开关阀高动态控制。在高速开关阀开启、关闭阶段中,在初始阶段采用较大的电压驱动(关闭阶段采用较大的负电压),当速度达到设定值时(速度可根据用户期望进行调整),为降低阀芯受到刚性冲击而产生的损耗,利用速度闭环控制器对占空比进行实时调整,使开启阶段和关闭阶段的最终速度的数值维持在较低的水平。本发明可以兼顾动态特性和柔性启闭,提高高速开关阀性能并延长其寿命。(The invention discloses a method for realizing controllable motion of a valve core of a high-speed switch valve based on a speed controller, and belongs to the field of control of the high-speed switch valve. A working period of the high-speed switch valve is divided into a plurality of stages, and the duty ratio of each stage of each period is controlled to enable the voltage source to output voltage square waves with corresponding duty ratios, so that the high-dynamic control of the high-speed switch valve is carried out. In the opening and closing stages of the high-speed switch valve, a larger voltage is adopted for driving in the initial stage (a larger negative voltage is adopted in the closing stage), and when the speed reaches a set value (the speed can be adjusted according to the expectation of a user), in order to reduce the loss generated by rigid impact on the valve core, the duty ratio is adjusted in real time by using the speed closed-loop controller, so that the final speed values in the opening stage and the closing stage are maintained at a lower level. The invention can give consideration to dynamic characteristics and flexible opening and closing, improve the performance of the high-speed switch valve and prolong the service life of the high-speed switch valve.)
1. A method for realizing the controllable motion of a valve core of a high-speed switch valve based on a speed controller is characterized in that,
a coil of the high-speed switch valve (6) is connected with the high-speed change-over switch (4) through a current detector (5), the high-speed change-over switch (4) is provided with three contact heads, wherein a first contact head (4-1) is connected with a first voltage source (2), a second contact head (4-2) is connected with a second voltage source (3), and a third contact head (4-3) is connected with the current detector (5); a displacement sensor (7) is arranged in the high-speed switch valve (6) and used for obtaining the motion state of the valve core of the high-speed switch valve; the pressure sensing system (8) is connected with the high-speed switch valve (6) to obtain the pressure state of each working port of the electromagnetic valve in real time; the controller (9) is connected with the displacement sensor (7) and the pressure sensor (8); the controller (9) is connected with the duty ratio controller (1); the output connected with the duty ratio controller (1) is respectively connected with a first voltage source (2) and a second voltage source (3); the controller (9) is connected with the high-speed change-over switch (4) and controls the connection state of the third contact (4-3) and other contacts; the controller (9) comprises a speed closed-loop controller (10);
dividing a working period of the high-speed switch valve into 8 stages, and controlling the high-speed switch valve by controlling the duty ratio output by a duty ratio controller (1) at each stage of each period, wherein in one period, the method comprises the following steps:
1) preloading excitation phase
Before the rising edge of the control signal comes, the controller controls the third contact head to be communicated with the first contact head in advance and triggers the duty ratio controller in advance, the duty ratio controller outputs a high-frequency square wave signal with the duty ratio of A to the first voltage source, the first voltage source outputs a corresponding voltage square wave, under the action of the voltage square wave, the current of the coil reaches a pre-loading current value, and the pre-loading current value is smaller than the starting current;
2) preload maintenance phase
After the pre-loading current value is reached, the controller triggers the duty ratio controller, the duty ratio controller outputs a high-frequency square wave signal with the duty ratio of B to the first voltage source, the first voltage source starts to output a voltage square wave with the duty ratio of B, and under the action of the voltage square wave, the coil current is always kept on the pre-loading current value to do high-frequency small fluctuation;
3) opening phase
When the rising edge of the control signal comes, the controller triggers the duty ratio controller, the duty ratio controller outputs a high-frequency square wave signal with the duty ratio of C to the first voltage source, the first voltage source outputs a corresponding voltage square wave, the current of the coil rises under the action of the voltage square wave, when the current of the coil reaches the opening current, the switch valve starts to be opened, the current continues to rise, at the moment, the electromagnetic force rises along with the current, and the valve core is in an accelerating state; when the speed of the valve core reaches the preset opening buffer speed V1Then, triggering the speed closed-loop controller, and ending the stage 3);
4) opening buffer stage
The speed of the valve core reaches V1Then, the controller controls the third contact head to be communicated with the second contact head, and the displacement sensor transmits the speed of the valve core to the speed closed-loop controller in real time; the speed closed-loop controller takes the speed of the valve core as an input quantity, and the speed is real-time compared with a preset opening buffer speed V1Comparing, adjusting the output duty ratio D of the duty ratio controller at this stage according to the comparison result, and outputting corresponding voltage by the second voltage source according to the real-time change of the duty ratio to stabilize the valve core speed at openingBuffer velocity V1Until the high-speed switch valve is completely opened;
5) maintenance phase
When the high-speed switch valve is completely opened, the controller controls the third contact to be communicated with the first contact, the displacement sensor outputs a signal to the controller, the controller triggers the duty ratio controller at the moment, the duty ratio controller outputs a high-frequency square wave signal with the duty ratio of E to the voltage source, the first voltage source outputs a corresponding voltage square wave, under the action of the voltage square wave, the current is reduced to the starting maintaining current to fluctuate until the falling edge of the control signal comes, and the starting maintaining current is larger than the closing current;
6) closing phase
When the falling edge of the control signal comes, the controller triggers the duty ratio controller, the duty ratio controller outputs a high-frequency square wave signal with the duty ratio of F to the first voltage source, the first voltage source outputs a corresponding voltage square wave, the coil current rapidly drops to a closing current under the action of the voltage square wave, at the moment, the high-speed switch valve starts to be closed, the voltage square wave continues to be excited, the current continues to drop, the electromagnetic force drops along with the current, the resultant force borne by the valve core is increased, and the speed of the valve core also continuously rises; when the speed of the valve core reaches the preset closing buffer speed V2Then, triggering the speed closed-loop controller, and ending the stage 6);
7) closing the buffer phase
The speed of the valve core reaches V2Then, the controller controls the third contact head to be communicated with the second contact head, and the displacement sensor transmits the speed of the valve core to the speed closed-loop controller in real time; the speed closed-loop controller takes the valve core speed as an input quantity, and the closing buffer speed V is real-time and preset2Comparing, adjusting the output duty ratio G of the duty ratio controller at this stage according to the comparison result, and outputting corresponding voltage by the second voltage source according to the real-time change of the duty ratio to stabilize the valve core speed at the closing buffer speed V2Until the high-speed switch valve is completely closed;
8) shutdown maintenance phase
When the high-speed switch valve is completely closed, the controller controls the third contact to be communicated with the first contact, the displacement sensor transmits a signal to the controller, the controller triggers the duty ratio controller, the duty ratio controller outputs a high-frequency square wave signal with the duty ratio of 0 to the first voltage source, the first voltage source outputs zero voltage, and the current is reduced to zero current; until the next cycle.
2. The method of claim 1 for enabling high speed switching valve spool motion control based on a speed controller, wherein the duty cycle A, B, C, E, F is constant for the duration of each phase.
3. The method for realizing the motion controllability of the valve core of the high-speed switching valve based on the speed controller according to claim 1, wherein the speed closed-loop controller works in a mode that: when the speed of the valve core is greater than the preset buffer speed, reducing the output duty ratio of the duty ratio controller; when the speed of the valve core is smaller than the preset buffer speed, the output duty ratio of the duty ratio controller is increased; and when the valve core speed is equal to the preset buffer speed, maintaining the current duty ratio.
4. The method for realizing the controllable motion of the valve core of the high-speed switch valve based on the speed controller as claimed in claim 1, wherein the duty ratio A of the preloading excitation stage is 100%.
5. The method for realizing the valve core movement controllability of the high-speed switch valve based on the speed controller according to claim 1, wherein the pre-loading current value is 90-95% of the opening current; the equivalent voltage of the voltage square wave with the duty ratio B is the product of the pre-loading current value and the coil resistance.
6. The method as claimed in claim 1, wherein the equivalent voltage of the voltage square wave with duty ratio E is the product of the turn-on maintaining current and the coil resistance, and the turn-on maintaining current is 105-110% of the turn-off current.
7. The method for realizing the controllable motion of the valve core of the high-speed switch valve based on the speed controller as claimed in claim 1, wherein the duty ratio C in the opening stage is 100%.
8. The method for realizing the controllable motion of the valve core of the high-speed switch valve based on the speed controller as claimed in claim 1, wherein the duty ratio E of the closing stage is-100%.
9. The method for realizing the valve core motion control of the high-speed switch valve based on the speed controller as claimed in claim 1, wherein the opening buffer speed V is1Less than 0.6 m/s. Closing buffer velocity V2Less than 0.2 m/s.
10. The method for controlling the motion of the valve core of the high-speed switching valve based on the speed controller as claimed in claim 1, wherein the amplitude of the first voltage source is smaller than that of the second voltage source.
Technical Field
The invention relates to the field of high-speed switch valve control, in particular to a method for realizing controllable motion of a valve core of a high-speed switch valve based on a speed controller.
Background
The high-speed switching valve receives an electrical signal, i.e., a pulse signal, from the pump valve controller. The high-speed switch valve completes a quick switching action every time receiving a pulse signal. In order to make the valve core realize high-speed movement, a higher forward voltage and a higher reverse voltage are respectively added in the opening and closing stages of the valve core, so that the induced current in the valve quickly rises, the electromagnetic force generated by the induced current quickly rises and reaches a larger value, and finally the valve core is accelerated and finally reaches a higher speed. This results in that when the valve is fully opened and closed in each period, the valve core may generate a large rigid impact on the valve body, the valve seat and other related hardware, causing damage to the valve core and other related components.
The high-speed switch valve is also a high-frequency switch valve, and the frequency of the pulse signal received by the high-speed switch valve is very high. The rigid impact generated by the valve spool when the valve opens and closes is also high frequency. The high-frequency periodic rigid impact has non-negligible damage to the valve body, and the service life of the high-speed switch valve is shortened.
However, if valve core protection is too pursued, a low voltage is adopted to excite the opening stage of the high-speed switch valve, and a zero voltage is adopted to excite the closing stage, so that the valve core has a low movement speed, the impact force is reduced, the dynamic characteristic is reduced, and the high-frequency control requirement cannot be matched. How to give consideration to both dynamic characteristics and flexible opening and closing is a technical problem to be solved urgently in the prior art.
The pulse width modulation is an analog control mode, and when the pulse width modulation is used for regulating and controlling the output of a voltage source, the voltage source can be controlled to output voltage square waves with corresponding duty ratios through the duty ratios of signals, so that the output of the voltage source is changed. Pulse width modulation is a very efficient technique for controlling analog circuits using digital signals from a microprocessor. Pulse width modulation is a very efficient technique for controlling analog circuits using the digital output of a microprocessor, and is widely used in many fields ranging from measurement, communications to power control and conversion.
Disclosure of Invention
In order to overcome the defects in the prior art, the method for realizing the motion control of the valve core of the high-speed switching valve based on the speed controller is provided.
The invention discloses a method for realizing the motion control of a valve core of a high-speed switch valve based on a speed controller, wherein a coil of the high-speed switch valve is connected with a high-speed change-over switch through a current detector, and the high-speed change-over switch is provided with three contact heads, wherein the first contact head is connected with a first voltage source, the second contact head is connected with a second voltage source, and the third contact head is connected with the current detector; a displacement sensor is arranged in the high-speed switch valve and used for acquiring the motion state of the valve core of the high-speed switch valve; the pressure sensing system is connected with the high-speed switch valve to obtain the pressure state of each working port of the electromagnetic valve in real time; the controller is connected with the displacement sensor and the pressure sensor to obtain the position and the movement speed of the valve core of the high-speed switch valve; 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 is connected with the duty ratio controller; the output connected with the duty ratio controller is respectively connected with a first voltage source and a second voltage source; the controller is connected with the high-speed selector switch and controls the connection state of the third contact and other contacts; the controller comprises a speed closed-loop controller; dividing a working cycle of the high-speed switching valve into 8 stages, and controlling the high-speed switching valve by controlling the duty ratio output by the duty ratio controller at each stage of each cycle, wherein in one cycle, the method comprises the following steps:
1) preloading excitation phase
Before the rising edge of the control signal comes, the controller controls the third contact head to be communicated with the first contact head in advance and triggers the duty ratio controller in advance, the duty ratio controller outputs a high-frequency square wave signal with the duty ratio of A to the first voltage source, the first voltage source outputs a corresponding voltage square wave, under the action of the voltage square wave, the current of the coil reaches a pre-loading current value, and the pre-loading current value is smaller than the starting current;
2) preload maintenance phase
After the pre-loading current value is reached, the controller triggers the duty ratio controller, the duty ratio controller outputs a high-frequency square wave signal with the duty ratio of B to the first voltage source, the first voltage source starts to output a voltage square wave with the duty ratio of B, and under the action of the voltage square wave, the coil current is always kept on the pre-loading current value to do high-frequency small fluctuation;
3) opening phase
When the rising edge of the control signal comes, the controller triggers the duty ratio controller, the duty ratio controller outputs a high-frequency square wave signal with the duty ratio of C to the first voltage source, the first voltage source outputs a corresponding voltage square wave, the current of the coil rises under the action of the voltage square wave, when the current of the coil reaches the opening current, the switch valve starts to be opened, the current continues to rise, at the moment, the electromagnetic force rises along with the current, and the valve core is in an accelerating state; when the speed of the valve core reaches the preset opening buffer speed V1Then, triggering the speed closed-loop controller, and ending the stage 3);
4) opening buffer stage
The speed of the valve core reaches V1Then, the controller controls the third contact head to be communicated with the second contact head, and the displacement sensor transmits the speed of the valve core to the speed closed-loop controller in real time; the speed closed-loop controller takes the speed of the valve core as an input quantity, and the speed is real-time compared with a preset opening buffer speed V1Comparing, adjusting the output duty ratio D of the duty ratio controller at this stage according to the comparison result, and outputting corresponding voltage by the second voltage source according to the real-time change of the duty ratio to stabilize the valve core speed at the opening buffer speed V1Until the high-speed switch valve is completely opened;
5) maintenance phase
When the high-speed switch valve is completely opened, the controller controls the third contact to be communicated with the first contact, the displacement sensor outputs a signal to the controller, the controller triggers the duty ratio controller at the moment, the duty ratio controller outputs a high-frequency square wave signal with the duty ratio of E to the voltage source, the first voltage source outputs a corresponding voltage square wave, under the action of the voltage square wave, the current is reduced to the starting maintaining current to fluctuate until the falling edge of the control signal comes, and the starting maintaining current is larger than the closing current;
6) closing phase
When the falling edge of the control signal comes, the controller triggers the duty ratio controller, the duty ratio controller outputs a high-frequency square wave signal with the duty ratio of F to the first voltage source, the first voltage source outputs a corresponding voltage square wave, the coil current rapidly drops to a closing current under the action of the voltage square wave, at the moment, the high-speed switch valve starts to be closed, the voltage square wave continues to be excited, the current continues to drop, the electromagnetic force drops along with the current, the resultant force borne by the valve core is increased, and the speed of the valve core also continuously rises; when the speed of the valve core reaches the preset closing buffer speed V2Then, triggering the speed closed-loop controller, and ending the stage 6);
7) closing the buffer phase
The speed of the valve core reaches V2Then, the controller controls the third contact head to be communicated with the second contact head, and the displacement sensor transmits the speed of the valve core to the speed closed-loop controller in real time; the speed closed-loop controller takes the valve core speed as an input quantity, and the closing buffer speed V is real-time and preset2Comparing, adjusting the output duty ratio G of the duty ratio controller at this stage according to the comparison result, and outputting corresponding voltage by the second voltage source according to the real-time change of the duty ratio to stabilize the valve core speed at the closing buffer speed V2Until the high-speed switch valve is completely closed;
8) shutdown maintenance phase
When the high-speed switch valve is completely closed, the controller controls the third contact to be communicated with the first contact, the displacement sensor transmits a signal to the controller, the controller triggers the duty ratio controller, the duty ratio controller outputs a high-frequency square wave signal with the duty ratio of 0 to the first voltage source, the first voltage source outputs zero voltage, and the current is reduced to zero current; until the next cycle.
The duty cycle A, B, C, E, F is constant for the duration of the respective phase. The duty cycles D and G may be adjusted.
The working mode of the speed closed-loop controller is as follows: when the speed of the valve core is greater than the preset buffer speed, reducing the output duty ratio of the duty ratio controller; when the speed of the valve core is smaller than the preset buffer speed, the output duty ratio of the duty ratio controller is increased; and when the valve core speed is equal to the preset buffer speed, maintaining the current duty ratio.
The invention realizes the control of the valve core movement speed by the speed controller, the final speed is set by a user according to the requirement, and the speed value can be adjusted as a preset value. In the fourth stage and the seventh stage of the invention, the valve core speed is finally kept at V through the real-time calculation and processing of the speed closed-loop controller1And V2The value is such that the rigidity impact on the high-speed switching valve at the time of full opening and full closing reaches a small value, and the damage caused by the impact also reaches a small value.
The duty ratio can be adjusted in real time through a duty ratio controller, and the change range of the duty ratio is-1; in order to further provide the dynamic characteristics of the method of the invention, the method is provided with a preloading maintaining phase and a starting maintaining phase, and in the two phases, the coil current is close to the starting current and the closing current, so that the dynamic characteristics of the starting phase and the closing phase are greatly improved.
As a preferred embodiment of the present invention, the amplitude of the first voltage source is smaller than that of the second voltage source, so that the speed closed-loop controller can control the current to be stabilized at the preset buffering speed in a short time during the corresponding buffering stage.
The duty ratios of the preloading stage, the opening stage and the closing stage can be selected to be larger values, such as 1, 1 and-1 respectively; the maximum equivalent voltage value is used for loading, the duration time of the corresponding stage can be reduced, and the electromagnetic valve is suitable for high-frequency working conditions.
The duty ratio of each stage of the invention is independently adjustable, thus different opening characteristic adjustment, closing characteristic adjustment and flexible opening and closing can be achieved according to requirements, and various requirements of the control working condition on the opening and closing characteristics can be met; and the duty ratio of the same stage under different periods can be adjusted, thereby greatly widening the working range of the high-frequency switch valve.
The pre-loading technology is adopted, and the pre-loading voltage is applied before the high-speed switch valve does not work, so that the current is increased to a pre-loading current value slightly smaller than the starting current. When the high-speed switching valve is operated, since the current has already reached the preload current value during the preload phase, the time taken for the current to rise to the opening current is very short, which improves the opening dynamics of the high-speed switching valve.
Drawings
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a schematic diagram of a speed closed loop controller.
Fig. 3 is a dynamic characteristic curve diagram from the opening stage to the maintaining stage of the high-speed switch valve in the scheme.
Fig. 4 is a dynamic characteristic graph from the closing phase to the closing maintaining phase of the high-speed switching valve of the scheme.
Fig. 5 is a graph showing the opening and closing characteristics of a high-speed on-off valve in a general case where this solution is not applied.
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.
As shown in fig. 1, the control system of this embodiment is used for implementing a method for implementing motion control of a valve element of a high-speed switching valve based on a speed controller, and includes a high-
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 control signals to participate in the operations of internal calculation, digital triggering and the like of the controller. For ease of illustration, the control signals are depicted outside 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.
As shown in fig. 2, the speed closed-
The displacement sensor can obtain the displacement and the speed of the valve core in real time. When the valve core is displaced, the displacement of the valve core causes the resistance of the potentiometer in the displacement sensor to change. The amount of change in resistance reflects the magnitude of the displacement. After the displacement magnitude is obtained, the controller conducts derivation according to the obtained displacement magnitude to obtain the speed of the valve core.
The present invention will be specifically described below as an example. The single duty cycle of the solenoid valve is divided into 8 phases. Wherein, the first represents a preloading excitation stage, the second represents a preloading maintenance stage, the third represents an opening stage, the fourth represents an opening buffer stage, the fifth represents a maintenance stage, the sixth represents a closing stage, the seventh represents a closing buffer stage, and the sixth represents a closing maintenance stage. The end time coincides with the rising edge time of the control signal, and the start time coincides with the falling edge of the control signal.
The method comprises the steps that a controller generates a control signal, before the rising edge of the control signal comes, the controller calculates the time required by increasing the current of a coil to a pre-loading current by adopting a pre-loading exciting voltage according to the current state of the coil and the parameters of the coil, the time is used as the duration time of a pre-loading exciting stage, the first stage is started according to the duration time of the pre-loading exciting stage, the controller controls a third contact to be communicated with a first contact in advance and triggers a duty ratio controller at the same time, the duty ratio controller outputs a high-frequency square wave signal with a duty ratio of 100% to a first voltage source, the first voltage source starts to output a voltage square wave with the duty ratio of 100%, and under the excitation of the high voltage, the current of the coil quickly reaches a value slightly smaller than an opening current to be in a high. The opening voltage and the opening current are the driving voltage and the coil current in the critical opening state of the electromagnetic valve;
because the duration of the first phase is calculated by the controller according to the current electrical parameters of the coil, the coil current is kept in a pre-loading current state slightly smaller than the starting current when the duration of the first phase is over. At the moment, the duration of the stage 1 is finished, the stage II is entered, the controller triggers the duty ratio controller, the duty ratio controller outputs a high-frequency square wave signal with the duty ratio of B to the first voltage source, the first voltage source starts to output a voltage square wave with the duty ratio of B, wherein 0< B <1, and under the action of the preloading maintaining voltage, the coil current is always kept in a preloading current state, namely a preloading current state which surrounds a value slightly smaller than the starting current and does high-frequency small-amplitude fluctuation. (stage two, the value of the modulated voltage is slightly less than the product of the opening current and the resistance)
And after the second stage is finished, namely when the rising edge of the control signal comes, the third stage is started, the controller triggers the duty ratio controller, the duty ratio controller outputs a high-frequency square wave signal with the duty ratio of 100% to the first voltage source, and the first voltage source outputs a voltage square wave with the duty ratio of 100%. The coil is excited by the modulated voltage sourceThe current rises rapidly, and because the current is already stabilized in a pre-loading current state before the control signal rises, the current rises to an opening current in a short time under the excitation of the modulated first voltage source, and then the valve core starts to move. The current continues to rise, the electromagnetic force rises along with the current, and the valve core is in an acceleration state. When the speed of the valve core reaches the opening buffer speed V1Triggering the speed closed-loop controller, ending the stage III and entering the stage IV.
The speed of the valve core reaches V1And entering a stage IV, controlling the third contact head to be communicated with the second contact head by the controller. The displacement sensor transmits the speed of the valve core to the speed closed-loop controller in real time. The speed closed-loop controller takes the valve core speed as an input quantity and takes the voltage as an output quantity. The controller obtains a voltage value output by the speed closed-loop controller and triggers the duty ratio controller, the duty ratio controller outputs a high-frequency square wave signal with the duty ratio of E to the second voltage source, and the second voltage source starts to output a voltage square wave with the duty ratio of D (starting buffer voltage).
Due to the hysteresis effect of the current, even in stage III when the speed of the spool reaches V1When the driving voltage is immediately reduced, the valve core still can do a small segment of acceleration movement due to the hysteresis effect of the current. Stage (iv) is to stabilize the valve core speed at V1. Because the resistance force applied to the valve core in the displacement process changes, the speed of the valve core is reduced to V1And is always kept at V1The value of the required drive voltage is varied. So the duty cycle E in phase 4 is also constantly changing, -1<E<1. Stage IV, the speed of the valve core is gradually stabilized at V1And performing uniform motion until the electromagnetic valve is completely opened.
This ensures that the losses experienced by the valve cartridge when fully open due to a rigid impact are of a small value.
When the electromagnetic valve is completely opened, the controller controls the third contact to be communicated with the first contact, the controller triggers the duty ratio controller, the duty ratio controller outputs a high-frequency square wave signal with the duty ratio of E to the first voltage source, the first voltage source starts to output a voltage square wave with the duty ratio of E (maintaining voltage which is slightly larger than closing voltage), wherein, the E is more than 0 and less than 1, under the action of the first voltage source modulated by the high-frequency square wave signal with the duty ratio of E, the coil current is always stabilized to be slightly larger than the maintaining current of the closing current, and the valve core is kept in an opening state and continues until the signal falling edge comes.
When the falling edge of the control signal comes, the controller triggers a duty ratio controller, the duty ratio controller outputs a high-frequency square wave signal with the duty ratio of-100% to a first voltage source, the first voltage source outputs reverse voltage, and the current rapidly falls to the current closing state under the excitation of the reverse voltage. At the moment, the electromagnetic valve starts to be closed, the first voltage source continues to excite, the current continues to fall, the electromagnetic force falls along with the current, the resultant force borne by the valve core is increased, and the speed of the valve core is also continuously increased. When the speed of the valve core reaches V2Triggering the speed closed-loop controller, ending the stage and entering the stage.
In stage (III), the speed of the valve core reaches V2The controller controls the third contact head to be communicated with the second contact head, and the displacement sensor transmits the speed of the valve core to the speed closed-loop controller in real time. The speed closed-loop controller takes the valve core speed as an input quantity and takes the voltage as an output quantity. The controller obtains a voltage value output by the speed closed-loop controller and triggers the duty ratio controller, the duty ratio controller outputs a high-frequency square wave signal with the duty ratio G to the second voltage source, and the second voltage source starts to output a voltage square wave with the duty ratio G (the buffer voltage is closed).
Due to the hysteresis effect of the current, even at stage (c) when the speed of the spool reaches V2When the driving voltage is immediately reduced, the valve core still can do a small segment of acceleration movement due to the hysteresis effect of the current. The purpose of stage is to stabilize the valve core speed at V2. Because the resistance force applied to the valve core in the displacement process changes, the speed of the valve core is reduced to V2And is always kept at V2The value of the required drive voltage is varied. So that the duty ratio G in the phase (c) is constantly changing-1<G1. Stage (c) the speed of the valve core is gradually stabilized at V2And performing uniform motion until the electromagnetic valve is completely opened.
When the electromagnetic valve is completely closed, the controller controls the third contact head to be communicated with the first contact head, the sensor outputs a signal to the controller in a stage of entering, the controller triggers the duty ratio controller, the duty ratio controller outputs a high-frequency square wave signal with the duty ratio of 0 to the first voltage source, and the first voltage source starts to output a voltage square wave with the duty ratio of 0, namely, the power is not supplied. Until the phase 1 of the next period comes, the system repeats the above process;
in the stage 4) and the stage 7), the speed closed-loop controller repeatedly compares the current valve core speed with a preset buffer speed according to a set working frequency, outputs a control signal to the duty ratio controller, and selects according to the required control precision when the comparison frequency is higher, wherein the control precision is higher.
As shown in fig. 2, when the spool speed is greater than the preset buffer speed, the output duty cycle of the duty cycle controller is reduced; when the speed of the valve core is smaller than the preset buffer speed, the output duty ratio of the duty ratio controller is increased; and when the valve core speed is equal to the preset buffer speed, maintaining the current duty ratio. The increase or decrease of the duty ratio value can be increased or decreased according to a certain percentage of the current duty ratio, and can also be increased or decreased according to a fixed increase or decrease amplitude. The present invention preferably increases or decreases by a percentage of the current duty cycle.
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 pre-loading current value is 90-95% of the starting current; the equivalent voltage of the voltage square wave with the duty ratio B is the product of the pre-loading current value and the coil resistance. The equivalent voltage of the voltage square wave with the duty ratio E is the product of the turn-on maintaining current and the coil resistance, and the turn-on maintaining current is 105-110% of the turn-off current.
The opening buffer speed V1Less than 0.6 m/s. Closing buffer velocity V2Less than 0.2 m/s.
The invention realizes the control of the valve core movement speed by the speed controller, the final speed is set by the user according to the requirement, and the speed value can be used as a preset valueAnd (4) adjusting. In the fourth stage and the seventh stage of the invention, the valve core speed is finally kept at V through the real-time calculation and processing of the speed closed-loop controller1And V2The value is such that the rigidity impact on the high-speed switching valve at the time of full opening and full closing reaches a small value, and the damage caused by the impact also reaches a small value. Opening buffer speed V1Or closing the buffer velocity V2If too small, the dynamics of the on-off valve may be poor, so it is desirable for the user to select as large a V as possible within the range of acceptable damping speeds1Or V2The value is obtained.
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.
Fig. 3 is a dynamic characteristic curve diagram from the opening stage to the maintaining stage of the high-speed switch valve adopting the scheme. Wherein the starting voltage is set to be 24V, and the amplitude of the high-frequency square wave signal in the starting buffer stage is-80V. In the opening buffer stage, under the control of the speed closed-loop controller, the duty ratio of the high-frequency square wave signal output by the duty ratio controller continuously changes, so that the equivalent voltage output by the voltage source also changes in real time, and the current fluctuates around the preset opening buffer speed. The preset opening buffer speed in the example of the figure is 0.3 m/s.
Fig. 4 is a dynamic characteristic graph from the closing phase to the closing maintaining phase of the high-speed switching valve adopting the scheme. Wherein the turn-off voltage is set to-24V, and the amplitude of the high-frequency square wave signal in the turn-off buffering stage is-80V. In the closing buffer stage, under the control of the speed closed-loop controller, the duty ratio of the high-frequency square wave signal output by the duty ratio controller continuously changes, so that the equivalent voltage output by the voltage source also changes in real time, and the current fluctuates around the preset closing buffer speed. The preset closing buffer speed in the example of the figure is-0.1 m/s.
Fig. 5 is a graph showing the opening and closing characteristics of a high-speed on-off valve in a general case where this solution is not applied. The turn-on voltage is 24V, and the turn-off voltage is 0V. In this case, the valve element opening speed finally reaches 0.6m/s, and the closing speed finally reaches-0.24 m/s.
From the comparison of fig. 3-5, it can be seen that the speed of the high-speed switch valve at the time of full opening is reduced from 0.6m/s to 0.3m/s after the scheme of the invention is adopted. The speed at full closure decreased from-0.24 m/s to-0.1 m/s. This realizes the flexible opening and closing function of the high-speed switch valve.
When realizing the flexible function of opening and close, this scheme has adopted the preloading technique, has improved the dynamic characteristic that opens of high-speed ooff valve. A larger reverse voltage is applied in the closing stage, so that the closing dynamic characteristic of the high-speed switch valve is improved.
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