CN211738171U

CN211738171U - High-dynamic high-frequency-response control system for electromagnetic valve

Info

Publication number: CN211738171U
Application number: CN202020050108.2U
Authority: CN
Inventors: 钟麒; 孙造诣; 何贤剑; 王军; 汪谢乐; 李研彪; 陈波; 孙鹏
Original assignee: Zhejiang University of Technology ZJUT
Current assignee: Zhejiang University of Technology ZJUT
Priority date: 2020-01-07
Filing date: 2020-01-07
Publication date: 2020-10-23
Anticipated expiration: 2030-01-07

Abstract

The utility model discloses a high developments high frequency response control system of solenoid valve. The system comprises a pre-loading high-voltage source, a pre-loading voltage stabilizing source, a high-voltage source, a reverse voltage source, a voltage stabilizing source, a negative voltage source, a zero-voltage source, a high-speed change-over switch, a current detector, an electromagnetic valve, a pressure sensing system and a controller; the pre-loading high-voltage source is loaded in advance before the expected opening and closing time of the electromagnetic valve, and the coil current is kept in a state slightly smaller than the opening current through the pre-loading voltage stabilizing source. In the starting stage, a high-voltage source is adopted for excitation, so that the current rises rapidly, and the movement time in the starting stage is reduced; a reverse voltage source is adopted for excitation before a maintenance stage, so that the current of the coil can be reduced from starting current to maintaining current more quickly; in the closing stage, the current is rapidly reduced to 0 by adopting the excitation of a negative voltage source, and the movement time of the closing stage is reduced.

Description

High-dynamic high-frequency-response control system for electromagnetic valve

Technical Field

The utility model relates to a solenoid valve control field, concretely relates to high developments high frequency response control system of solenoid valve.

Background

In the solenoid valve, the ampere-turns and the working air gap have the greatest influence on the electromagnetic force of the electromagnet. Ampere-turns is the product of the number of turns of the coil and the current in the single coil. In the case where the magnetic flux is not saturated, the larger the current, the larger the electromagnetic force; the smaller the working air gap, the greater the electromagnetic force. Since the solenoid valve is usually opened when the working air gap in the electromagnet is largest, and closed when the working air gap in the electromagnet is smallest, the opening current is larger than the closing current.

At present, most hydraulic electromagnetic valves adopt a single-voltage control mode, namely after the electromagnetic valve is powered on, the driving voltage increases the current in a circuit, meanwhile, the electromagnetic force generated by the current is increased, and when the electromagnetic force is increased enough to overcome the working resistance of an electromagnet, the electromagnetic valve is opened; after the driving voltage is closed, the current in the circuit is reduced, the electromagnetic force is reduced along with the current, and when the electromagnetic force is reduced to be insufficient to overcome the working resistance of the electromagnetic valve, the electromagnetic valve begins to reset.

However, this method is not suitable for applications where high demands are made on the dynamic response of the solenoid valve. Due to the inductive effect of the electromagnet and the coil, a certain hysteresis is created both at the moment of opening and closing the valve. If a smaller driving voltage is adopted, the rising speed of the current is slow in the starting stage, so that a longer starting lag time is caused; if a larger driving voltage is used, a longer turn-off delay time may be caused due to a large initial current during turn-off. Therefore, the single voltage source control method cannot simultaneously shorten the lag time of the solenoid valve during opening and closing.

In the prior art, a 3-voltage source control mode is adopted in the field of high-frequency electromagnetic valves to achieve a high-frequency control function, and a high-voltage source is adopted as excitation voltage in a patent [ CN201610015304.4] to enable the electromagnetic valves to be opened in a short time; the voltage-stabilized power supply provides a maintaining voltage to keep the current at a value slightly larger than the closing current; the negative voltage source provides a large reverse voltage to reduce the current to the off current in a short time. The effect of shortening the lag time of the electromagnetic valve during opening and closing simultaneously is achieved.

However, the existing 3-voltage source control (CN 201610015304.4) only divides one cycle into four stages to achieve the effects of shortening the cycle time and increasing the operating frequency of the solenoid valve, but does not further optimize each stage. Certain measures can be taken in the stages of opening, maintaining and closing the electromagnetic valve, so that the time consumption of each stage is shortened, and the working frequency of the high-frequency electromagnetic valve can be greatly improved.

Disclosure of Invention

In order to solve the difficult point, the utility model provides a high developments high frequency response control system of solenoid valve.

The utility model discloses a high dynamic high frequency response control system of solenoid valve at first, it includes preloading high voltage source, preloading steady voltage source, high voltage source, reverse voltage source, steady voltage source, negative voltage source, zero voltage source, high-speed change over switch, current detector, solenoid valve, pressure sensing system and controller;

the high-speed change-over switch comprises eight contact heads, wherein a first contact head is connected with a pre-loading high-voltage source, a second contact head is connected with a pre-loading voltage stabilizing source, a third contact head is connected with the high-voltage source, a fourth contact head is connected with a reverse voltage source, a fifth contact head is connected with the voltage stabilizing source, a sixth contact head is connected with a negative voltage source, a seventh contact head is connected with a zero-voltage source, and an eighth contact head is connected with a current detector; the current detector is connected with a coil of the electromagnetic valve, and the pressure sensing system is connected with the electromagnetic valve to obtain the pressure state of each working port of the electromagnetic valve in real time; the controller is connected with the pressure sensing system and comprises a control signal generating unit; and the output port of the controller is connected with the high-speed selector switch and can control the contact state of the eighth contact and the rest 7 contacts.

As the preferred embodiment of the present invention, the control signal generated by the control signal generating unit is a square wave signal, and the duty ratio of the square wave signal is the ratio of the target opening time to the cycle time of the solenoid valve. 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.

As the preferred embodiment of the present invention, the controller obtains the duty ratio, the frequency, the rising edge time and the falling edge time of the control signal generated by the control signal generating unit in real time.

The utility model has the advantages that:

(1) and the pre-loading stage (comprising a pre-loading excitation stage and a pre-loading maintaining stage) adopts two-stage voltage source excitation, namely, a pre-loading high voltage source is firstly used for excitation, so that the current of the coil is quickly increased to a pre-loading current value. And then the current is maintained in a pre-loading current state by a pre-loading voltage stabilizing source. Conventional methods for implementing the preload current function typically employ a single voltage for the preload excitation, since the preload current is a relatively fixed value, and the corresponding preload voltage is also relatively fixed in combination with the current resistance situation, and is equal to the product of the preload current and the resistance. The preload voltage in the conventional method is smaller than the preload excitation voltage in the present invention, so the current increases at a slower rate under the action of the preload voltage, resulting in a longer time required for the current to increase to the preload current, and the whole preload process is prolonged. Therefore, for some high-frequency switches, the method of preloading by using a single voltage source often cannot meet the requirement of higher-frequency on-off. Furthermore, as the duty cycle varies, when the duty cycle is high, the time left to open the preload stage is reduced, and when the time is reduced such that the current cannot be increased to the preload current, the effect of the preload stage is further reduced. Therefore, there are many limitations to the method of performing the preloading using a single voltage. The utility model discloses a method only uses the control mode of one section voltage source to compare with the preloading stage, owing to adopt the excitation of high voltage source, the rate of current rise is bigger, and the current will be faster rises to preloading current state, makes the preloading stage consuming time shorter. The method is suitable for occasions with higher switching frequency.

(2) Because the coil current is maintained in a state slightly smaller than the opening current of the electromagnetic valve after the preloading stage is finished, the opening current can be reached in a short time in the opening stage, and the electromagnetic valve is opened immediately, so that the dynamic characteristic of the opening stage of the electromagnetic valve is better, and the lag time of the electromagnetic valve during opening is shortened.

(3) The reverse excitation stage adopts a reverse voltage source for excitation, so that the current of the coil can be more quickly reduced from the starting current after the starting stage is finished to the maintaining current, and the action time of the voltage stabilizing source in the prior art is greatly shortened. In the prior art, a voltage stabilizing source is adopted for excitation, so that the current is finally stabilized in a state slightly larger than the closed current, but the voltage stabilizing source is adopted for direct excitation, and the time required for the current to be reduced to the maintenance current is long. If the frequency of the control signal is high, the situation may occur that the current is not reduced to the holding current, and the falling edge of the control signal is already reached, which is not favorable for further optimization of the dynamic characteristic of the solenoid valve. And the utility model discloses, adopt reverse voltage with reverse excitation stage, the maintenance stage adopts holding voltage's method, can utilize reverse voltage's off-load characteristic, reduces the electric current to holding current fast, then through the holding voltage of maintenance stage, makes the electric current keep the state at holding current always. Compared with the prior art, the utility model, after the high voltage excitation (think that the solenoid valve has opened completely promptly), just insert reverse voltage at once, make the electric current reduce to the holding current fast, not only reduced the average current size in the duty cycle, reduced the electromagnetism energy consumption, still make the solenoid valve can adapt to better the operating mode of opening and close.

(4) In this patent, the duration of the opening phase is specified in such a way that the solenoid valve is energized with the high-voltage source to the time required to complete the stroke in the 0 current state.

Generally, the dynamic characteristics of a solenoid valve are weak, while the current dynamic characteristics of the solenoid coil are good. In the prior art, as in patent [ CN201610015304.4], the high voltage source is switched to a lower steady voltage source immediately after the current is increased to the opening current, which results in that the dynamic characteristic of the solenoid valve is weaker and the current dynamic characteristic of the solenoid coil is better, so that when the coil current reaches the opening current, the valve is still in the opening motion state and does not complete the stroke. At this time, the high voltage source is immediately switched to the steady voltage source, so that the driving force of the opening stage of the electromagnetic valve is reduced, and the dynamic characteristic of the opening stage of the electromagnetic valve is reduced. In this patent, the duration of phase 3 is defined as the time required for the solenoid valve to be energized to complete its stroke with the high voltage source in the 0 current state. Since, if the valve is fully opened by the high voltage excitation in the 0 current state, the same excitation time is certainly sufficient to fully open the valve already with a certain pre-load current (the dynamic characteristics of the opening phase can be maximally ensured by continuing the high voltage excitation during this time).

(5) In the prior art, as in patent [ CN201610015304.4], during the closing phase of the solenoid valve, the current is reduced to the closing current by a negative voltage and then is switched to zero voltage immediately. The method has the disadvantages that when the dynamic characteristic of a part of switch valves is weak and the current dynamic characteristic of the electromagnetic coils is good, when the current is reduced to a closing current, the valve is in a closing motion state, and at the moment, the negative voltage is switched to zero voltage, so that the driving force of the electromagnetic valve in the closing stage is reduced, and the dynamic characteristic of the valve in the closing stage is reduced. And the utility model discloses adopt the excitation of negative voltage source to directly reduce to 0 with the electric current in the stage of closing, because the electromagnetic force that produces during 0 electric current is minimum, makes the drive power of closing the in-process keep at the maximum value always, and the fastest that the valve was closed.

(6) The multi-voltage source control mode greatly shortens the time of the voltage at a high position in one period, can reduce the heating of the coil to the maximum extent and prolongs the service life of equipment.

Drawings

Fig. 1 is a schematic structural view of the high dynamic control system of the voltage source solenoid valve of the present invention;

fig. 2 is a graph of control signals and current curves according to the present invention;

FIG. 3 is the opening and closing characteristics of a single voltage driven solenoid valve;

FIG. 4 illustrates the on/off characteristics of the solenoid valve driven by the system and method of the present invention;

fig. 5 shows the opening and closing characteristics of the solenoid valve of the comparative example not including the reverse voltage source.

Detailed Description

The invention is further described with reference to the drawings and the specific embodiments.

As shown in fig. 1, the system of this embodiment includes a preloaded high voltage source (1), a preloaded regulated voltage source (2), a high voltage source (3), a reverse voltage source (4), a regulated voltage source (5), a negative voltage source (6), a zero voltage source (7), a high-speed switch (8), a current detector (9), a solenoid valve (10), a pressure sensing system (11), and a controller (12);

the controller 12 includes a control signal generating unit, the control signal 13 is generated by an operator through programming of the control signal generating unit inside the controller, and the control signal participates in the operation inside the controller. The controller 11 acquires the duty ratio, the frequency, the rising edge time and the falling edge time of the control signal generated by the control signal generating unit in real time.

The high-speed change-over switch (8) comprises eight contact heads, wherein a first contact head (8-1) is connected with a pre-loading high-voltage source (1), a second contact head (8-2) is connected with a pre-loading voltage stabilizing source (2), a third contact head (8-3) is connected with a high-voltage source (3), a fourth contact head (8-4) is connected with a reverse voltage source (4), a fifth contact head (8-5) is connected with a voltage stabilizing source (5), a sixth contact head (8-6) is connected with a negative voltage source (6), a seventh contact head (8-7) is connected with a zero voltage source (7), and an eighth contact head (8-8) is connected with a current detector (9); the current detector (9) is connected with a coil of the electromagnetic valve (10), and the pressure sensing system (11) is connected with the electromagnetic valve to obtain the pressure state of each working port of the electromagnetic valve in real time; the controller (12) is connected with the pressure sensing system, and the controller (12) comprises a control signal generating unit; and an output port of the controller (12) is connected with the high-speed selector switch and can control the contact state of the eighth contact (8-8) and the rest 7 contacts.

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. 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.

The single duty cycle of the solenoid valve is divided into 7 phases, as shown in fig. 2, and is represented by arabic numerals 1-7, respectively. Where 1 represents the preload actuation phase, 2 represents the preload hold phase, 3 represents the on phase, 4 represents the reverse actuation phase, 5 represents the hold phase, 6 represents the off phase, and 7 represents the off hold phase. The end time of the phase 2 coincides with the rising edge time of the control signal, and the end time of the phase 5 coincides with the falling edge time of the control signal.

The controller generates a control signal, and calculates the time required for increasing the coil current to the preload current by adopting the preload excitation voltage according to the current coil current state and the parameters of the coil before the rising edge of the control signal comes, and the time is taken as the duration of the preload excitation stage. Depending on the duration of the preload activation phase, the controller brings the eighth contact into communication with the first contact in advance into phase 1. Under the action of the pre-loaded high voltage source, the coil current will quickly reach the pre-loaded current value. The preload high voltage source (1) voltage is equal to the high voltage source (3) voltage. The preload current is slightly less than the turn-on current.

Since the duration of phase 1 is calculated by the controller from the current coil electrical parameters, the current level reaches exactly the preload opening current when the duration of phase 1 is over. At the moment, the duration time of the phase 1 is over, the controller controls the eighth contact and the second contact to be communicated to enter the phase 2, and under the action of the pre-loading voltage stabilizing source, the current is always maintained in the pre-loading current state reached after the phase 1 is over. The voltage of the pre-loading voltage stabilizing source is equal to the product of the pre-loading starting current and the coil resistance.

After the stage 2 is finished, namely when the rising edge of the control signal comes, the controller controls the eighth contact and the third contact to be communicated to enter the stage 3, the current of the coil rapidly rises under the excitation of the high-voltage source, and as the current is stabilized in a preloading current state slightly lower than the opening current in the preloading stage, the current rises to the opening current in a short time in the stage 3, then the valve core starts to move, and the electromagnetic valve enters the opening stage. The high voltage source continues to maintain, and the maintaining time is equal to the time required by exciting the electromagnetic valve to complete the stroke by adopting the high voltage source under the 0 current state of the electromagnetic valve;

and after the stage 3 is finished, the controller controls the eighth contact and the fourth contact to be communicated to enter the stage 4, the controller calculates the time required by the coil current to be reduced to the maintaining current (the maintaining current is slightly larger than the closing current) from the opening current after the stage 3 is finished under the action of the reverse voltage source according to the current coil parameter and the coil current, and the time is the duration time of the stage 4.

Under the action of the reverse voltage source, the current of the coil is rapidly reduced, and when the stage 4 is finished, the current is reduced to a maintaining current state so as to keep the opening state of the electromagnetic valve;

after the stage 4 is finished, the controller controls the eighth contact and the fifth contact to be communicated to enter the stage 5, because the duration time of the stage 4 is calculated by the controller according to the current electrical parameters of the coil, when the duration time of the stage 4 is finished, the current just reaches the holding current. Under the action of the voltage stabilizing source, the current of the coil is always stabilized in a current state after the stage 4 is finished so as to ensure that the electromagnetic valve is continuously in a closed state; (the magnitude of the regulated voltage source is equal to the product of the holding current and the resistance)

After the stage 5 is finished, namely the falling edge of the control signal arrives, the controller controls the eighth contact and the sixth contact to be communicated to enter a stage 6, the current rapidly drops to a closing current under the action of the negative voltage source, the electromagnetic valve starts to be closed at the moment, the negative voltage source continues to be excited until the current is reduced to 0, and the stage 6 is finished at the moment;

after the stage 6 is finished, the controller controls the eighth contact and the seventh contact to be communicated to enter a stage 7, under the action of a zero voltage source, the coil keeps a zero current state until the stage 1 of the next period comes, and the system repeats the process;

in the scheme, the voltage value of the pre-loading voltage stabilizing source is slightly smaller than the product of the resistance of the solenoid valve coil and the opening current, and is generally smaller than 5% -10% of the product of the resistance of the solenoid valve coil and the opening current, namely the pre-loading voltage stabilizing source is adopted for excitation, when the current is stable, the current is smaller than 5% -10% of the opening current, and the current is pre-loading current; the voltage value of the voltage stabilizing source is slightly larger than the product of the coil resistance and the closing current of the electromagnetic valve, generally larger than 5% -10% of the product of the coil resistance and the closing current of the electromagnetic valve, namely the voltage stabilizing source is adopted for excitation, when the current is stable, the current is larger than 5% -10% of the closing current, and the current is maintained.

The calculation of the duration required for the pre-load excitation phase (phase 1) in the scheme is: the controller calculates the time required by the current of the coil to rise to the preloading current according to the current driving voltage, the current of the solenoid valve, the linear inductance resistance and the inductance, and the time is used as the duration time of the stage 1;

the duration required for the preload maintenance phase (phase 2) in the scheme is: the duration is 1-2 ms under normal conditions, and the duration can be increased or decreased properly according to different working conditions;

the calculation of the duration required for the start-up phase (phase 3) in the scheme is: the duration time of the high voltage is equal to the time required by the electromagnetic valve to complete the stroke by adopting the high voltage source to excite the electromagnetic valve in a 0 current state, namely the duration time of the stage 3; the starting time of the phase 3 is the arrival time of the rising edge of the control signal. According to the arrival time of the rising edge of the control signal and the duration of the phase 1 and the phase 2, the controller automatically calculates the starting time and the ending time of the phase 1 and the phase 2.

The calculation of the duration required for the reverse excitation phase (phase 4) in the scheme is: and the coil current after the phase 3 is started to be reduced to the time required by maintaining the current under the excitation of the reverse voltage source.

The calculation of the duration required for the maintenance phase (phase 5) in the scheme is: the time from the end time of phase 4 to the arrival time of the falling edge of the control signal.

The duration required for the shutdown phase (phase 6) in the scheme is calculated as: and the time required for the maintaining current after the phase 5 to drop to 0 current under the excitation of the negative voltage source.

The duration required to turn off the maintenance phase (phase 7) in the scheme is calculated as: the time that the end time of phase 6 lasts until the start time of the next phase 1.

As shown in fig. 3, which is a schematic diagram of the opening and closing characteristics of a solenoid valve driven by a single voltage of 24V, it can be seen from the figure that the opening of the solenoid valve lags behind 3ms, the opening movement lags behind 2ms, the closing movement lags behind 6.8ms, and the closing movement is 6.1ms after tests.

As shown in fig. 4, the opening and closing characteristics of the solenoid valve controlled by the system and method of the present invention are schematically shown, in this embodiment, the voltages of the preload high voltage source (1), the preload regulated voltage source (2), the high voltage source (3), the reverse voltage source (4), the regulated voltage source (5), the negative voltage source (6) and the zero voltage source (7) are 24V, 8V, 24V, -24V, 5V, -24V, 0V, respectively; the test results show that the opening lag is 0.2ms, the opening movement is 1.9ms, the closing lag is 0.1ms and the closing movement is 1.7 ms. As shown in fig. 4, the present invention is characterized in that when the coil current arrives at the opening command signal, the coil current is already stabilized at the pre-loading current stage, and in the opening stage, the high voltage excitation time is set to be equal to the time required by the solenoid valve to complete the stroke when the solenoid valve is in the 0 current state, so as to ensure the complete opening of the solenoid valve. The utility model discloses well design has the reverse excitation stage, and in the reverse excitation stage, adopts voltage value to equal high voltage source reverse voltage source, makes the coil current descend fast to the holding current, and this average current size in not only having reduced duty cycle has reduced the electromagnetism energy consumption, still makes the solenoid valve can adapt to better the operating mode of opening and close.

Fig. 5 shows a comparative example without a reverse excitation phase, which is similar to the present application but does not include a reverse excitation phase. The voltage sources of the comparative example include a preloaded high voltage source, a preloaded regulated voltage source, a high voltage source, a regulated voltage source, a negative voltage source, and a zero voltage source, and the voltages are 24V, 8V, 24V, 5V, -24V, and 0V, respectively. From the comparison of fig. 4 and fig. 5, the utility model discloses an add reverse voltage source (4) for the coil current reduces to the time of holding current greatly, can be better be applicable to the higher occasion of control signal frequency.

Claims

1. A high-dynamic high-frequency-response control system of an electromagnetic valve is characterized by comprising a pre-loading high-voltage source (1), a pre-loading voltage stabilizing source (2), a high-voltage source (3), a reverse voltage source (4), a voltage stabilizing source (5), a negative voltage source (6), a zero voltage source (7), a high-speed switch (8), a current detector (9), an electromagnetic valve (10), a pressure sensing system (11) and a controller (12);

2. The high-dynamic high-frequency response control system for the electromagnetic valve according to claim 1, wherein the control signal generated by the control signal generating unit is a square wave signal, and the duty ratio of the square wave signal is the target opening time and the cycle time ratio of the electromagnetic valve.

3. The high-dynamic high-frequency response control system of the electromagnetic valve according to claim 1, characterized in that the controller (12) obtains the duty ratio, the frequency, the rising edge time and the falling edge time of the control signal generated by the control signal generating unit in real time.