A high-dynamic high-frequency response control system and method for a solenoid valve

Abstract

The present invention discloses a high-dynamic high-frequency response control system and method for a solenoid valve. The system includes a pre-loaded high-voltage source, a pre-loaded stable-voltage source, a high-voltage source, a reverse-voltage source, a stable-voltage source, a negative-voltage source, a zero-voltage source, a high-speed switching switch, a current detector, a solenoid valve, a pressure sensing system, and a controller; before the expected opening and closing moments of the solenoid valve, the pre-loaded high-voltage source is pre-loaded in advance, and the coil current is maintained at a state slightly less than the opening current through the pre-loaded stable-voltage source. In the opening stage, the high-voltage source is used for excitation to rapidly increase the current, reducing the movement time in the opening stage; before the maintaining stage, the reverse-voltage source is used for excitation, which can more quickly reduce the coil current from the opening current to the maintaining current; in the closing stage, the negative-voltage source is used for excitation to rapidly reduce the current to 0, reducing the movement time in the closing stage.

Description

Technical Field

[0001] The present invention relates to the field of solenoid valve control, and particularly to a high-dynamic high-frequency response control system and method for a solenoid valve. Background Art

[0002] In a solenoid valve, the ampere-turns and the working air gap have the greatest influence on the electromagnetic force of the electromagnet. The ampere-turns is the product of the number of turns of the coil and the current in a single-turn coil. In the case where the magnetic flux is not saturated, the greater the current, the greater the electromagnetic force; the smaller the working air gap, the greater the electromagnetic force. Since the working air gap in the electromagnet is often the largest when the solenoid valve is opened, and the smallest when the solenoid valve is closed, the opening current is larger than the closing current.

[0003] Currently, most hydraulic solenoid valves adopt a single-voltage control method. That is, after the solenoid valve is powered on, the driving voltage increases the current in the circuit, and at the same time, the electromagnetic force generated by the current also increases. When the electromagnetic force increases to be sufficient to overcome the working resistance of the electromagnet, the solenoid valve opens; after the driving voltage is turned off, the current in the circuit decreases, and at the same time, the electromagnetic force decreases. When the electromagnetic force decreases to be insufficient to overcome the working resistance of the solenoid valve, the solenoid valve starts to reset.

[0004] However, this method is not applicable to occasions with high requirements for the dynamic response of the solenoid valve. Due to the inductance effect of the electromagnet and the coil, a certain lag will occur at the moment when the valve opens and closes. If a smaller driving voltage is adopted, the current rising speed is slow during the opening stage, resulting in a longer opening lag time; if a larger driving voltage is adopted, due to the large initial current during closing, a longer closing lag time will be caused. Therefore, the single-voltage source control method cannot shorten the solenoid valve lag time during both opening and closing at the same time.

[0005] In the prior art, a 3-voltage source control method is adopted in the field of high-frequency solenoid valves to achieve high-frequency control functions. In patent [CN201610015304.4], a high-voltage source is used as the excitation voltage to open the solenoid valve in a short time; a regulated power supply provides a maintaining voltage to keep the current at a value slightly greater than the closing current; a negative voltage source provides a large reverse voltage to make the current drop to the closing current in a short time. The effect of shortening the solenoid valve lag time during both opening and closing at the same time is achieved.

[0006] However, the existing 3-voltage source control (patent [CN201610015304.4]) method only divides one cycle into four stages to achieve the effect of shortening the cycle time and increasing the working frequency of the solenoid valve, but does not further optimize each stage. Certain measures can be taken during the opening, maintaining, and closing stages of the solenoid valve to shorten the time consumption of each stage, which can greatly increase the working frequency of the high-frequency solenoid valve. Summary of the Invention

[0007] To solve the above-mentioned difficulties, the present invention proposes a solenoid valve high-dynamic high-frequency response control system and its method.

[0008] The present invention first discloses a solenoid valve high-dynamic high-frequency response control system, which includes a pre-loaded high-voltage source, a pre-loaded stable voltage source, a high-voltage source, a reverse voltage source, a stable voltage source, a negative voltage source, a zero voltage source, a high-speed switching switch, a current detector, a solenoid valve, a pressure sensing system and a controller;

[0009] The high-speed switching switch has eight contacts. The first contact is connected to the pre-loaded high-voltage source, the second contact is connected to the pre-loaded stable voltage source, the third contact is connected to the high-voltage source, the fourth contact is connected to the reverse voltage source, the fifth contact is connected to the stable voltage source, the sixth contact is connected to the negative voltage source, the seventh contact is connected to the zero voltage source, and the eighth contact is connected to the current detector; the current detector is connected to the coil of the solenoid valve, and the pressure sensing system is connected to the solenoid valve to obtain the pressure state of each working port of the solenoid valve in real time; the controller is connected to the pressure sensing system, and the controller includes a control signal generation unit; the output port of the controller is connected to the high-speed switching switch and can control the contact state of the eighth contact with the remaining seven contacts.

[0010] As a preferred solution of the present invention, the control signal generated by the control signal generation unit is a square wave signal, and the duty cycle of the square wave signal is the ratio of the target opening time of the solenoid valve to the cycle time. The rising edge of the control signal indicates that the operator hopes the solenoid valve to open, the high potential of the control signal indicates that the operator hopes the solenoid valve to be in the open state, the falling edge of the control signal indicates that the operator hopes the solenoid valve to close, and the low potential of the control signal indicates that the operator hopes the solenoid valve to be in the closed state.

[0011] As a preferred solution of the present invention, the controller real-time obtains the duty cycle, frequency, rising edge time and falling edge time of the control signal generated by the control signal generation unit.

[0012] The present invention also discloses a control method for the above system, which includes the following steps:

[0013] The controller generates a control signal. Before the rising edge of the control signal arrives, the controller calculates the time required to increase the coil current to the pre-loaded current using the pre-loaded excitation voltage according to the current coil current state and the parameters of the coil, and takes this time as the duration of the pre-loaded excitation stage; according to the duration of the pre-loaded excitation stage, the controller advances to connect the eighth contact with the first contact to enter the pre-loaded excitation stage; under the action of the pre-loaded high-voltage source, the coil current reaches the pre-loaded current value;

[0014] After reaching the preloading current value, the controller controls the eighth contact to connect with the second contact to enter the preloading maintenance stage. Under the action of the preloading stable voltage source, the current is maintained at the preloading current state all the time;

[0015] When the rising edge of the control signal arrives, the controller controls the eighth contact to connect with the third contact to enter the opening stage. Under the excitation of the high voltage source, the current of the coil rises rapidly. Subsequently, the spool starts to move and the solenoid valve enters the opening stage; the high voltage source continues to be maintained until it is ensured that the solenoid valve is fully opened;

[0016] Then the controller controls the eighth contact to connect with the fourth contact to enter the reverse excitation stage; the controller calculates, according to the coil parameters and the current coil current, the time required for the coil current to drop from the opening current after the end of the opening stage to the holding current under the action of the reverse voltage source. This time is the duration of the reverse excitation stage; under the action of the reverse voltage source, the coil current drops rapidly, and the current drops to a holding current state greater than a set proportion of the closing current to keep the solenoid valve in the open state;

[0017] After that, the controller controls the eighth contact to connect with the fifth contact to enter the holding stage. Under the action of the stable voltage source, the coil current is kept stable at the holding current state all the time to keep the solenoid valve in the open state;

[0018] When the falling edge of the control signal arrives, the controller controls the eighth contact to connect with the sixth contact to enter the closing stage. Under the action of the negative voltage source, the current drops rapidly to the closing current. At this time, the solenoid valve starts to close, and the negative voltage source continues to be excited until the current drops to 0;

[0019] The controller controls the eighth contact to connect with the seventh contact to enter the closing maintenance stage. Under the action of the zero voltage source, the coil always maintains a zero current state until the next cycle arrives.

[0020] As a preferred solution of the present invention, the voltage of the preloading high voltage source is equal to the voltage of the high voltage source, and the preloading current is less than the set proportion of the opening current.

[0021] As a preferred solution of the present invention, the magnitude of the preloading stable voltage source is equal to the product of the preloading opening current and the coil resistance.

[0022] As a preferred solution of the present invention, the voltage value of the stable voltage source is greater than the product of the solenoid valve coil resistance and the closing current.

[0023] As a preferred solution of the present invention, the magnitude of the reverse voltage source is the same as that of the high voltage source, and the current direction is opposite.

[0024] As a preferred embodiment of the present invention, the calculation process of the duration required for the preloading excitation stage is as follows: The controller calculates the time required for the coil current to rise to the preloading current based on the current solenoid valve current, coil resistance, and inductance, and uses this as the duration of the preloading excitation stage.

[0025] As a preferred embodiment of the present invention, the duration of the preloading maintenance stage is 1 - 2 ms;

[0026] As a preferred embodiment of the present invention, the duration of the opening stage is equal to the time required to fully open the solenoid valve by exciting it with the high voltage source when the solenoid valve is in the 0 - current state.

[0027] The beneficial effects of the present invention are as follows:

[0028] (1) In the preloading stage (including the preloading excitation stage and the preloading maintenance stage), two - stage voltage source excitation is adopted. First, the preloading high - voltage source is used for excitation to rapidly increase the coil current to the preloading current value. Then, the preloading stable voltage source is used to maintain the current at the preloading current state. The traditional method for realizing the function of preloading current usually uses a single voltage for preloading excitation. Since the preloading current is a relatively fixed value, combined with the current resistance situation, the corresponding preloading voltage is also relatively fixed, and its magnitude is equal to the product of the preloading current and the resistance. The preloading voltage in the traditional method is smaller than the preloading excitation voltage in the present invention. Therefore, the growth rate of the current under the action of this preloading voltage is slower, resulting in a longer time required for the current to increase to the preloading current, and the entire preloading process is prolonged. Therefore, for some high - frequency switching occasions, the method of using a single voltage source for preloading often cannot meet the requirements of higher - frequency opening and closing. Moreover, as the duty cycle changes, when the opening duty cycle is relatively large, the time left for the opening preloading stage will be reduced. When the time is reduced to a point where the current cannot rise to the preloading current, the role of the preloading stage will be further weakened. Therefore, there are many limitations in the method of using a single voltage for preloading. Compared with the control method that only uses one - stage voltage source in the preloading stage, the method of the present invention has a greater current rise rate due to the use of a high - voltage source for excitation, and the current will rise to the preloading current state faster, making the preloading stage take less time. It is applicable to some occasions with higher switching frequencies.

[0029] (2) Since the coil current has been maintained at a state slightly less than the solenoid valve opening current after the preloading stage, it only takes a very short time to reach the opening current in the opening stage, and then the solenoid valve opens, making the dynamic characteristics of the solenoid valve opening stage better and shortening the lag time when the solenoid valve opens.

[0030] (3) In the reverse excitation stage, a reverse voltage source is used for excitation, which can more quickly reduce the coil current from the turn-on current after the end of the turn-on stage to the holding current, greatly shortening the action time of the steady voltage source in the prior art. The prior art all uses a steady voltage source for excitation, so that the current finally stabilizes at a state slightly greater than the turn-off current. However, when directly using a steady voltage source for excitation, the time required for the current to drop to the holding current is long. If the control signal frequency is high, it is possible that the falling edge of the control signal arrives before the current has dropped to the holding current, and such a situation is not conducive to further optimizing the dynamic characteristics of the solenoid valve. In the present invention, by using a reverse voltage in the reverse excitation stage and a holding voltage in the holding stage, the unloading characteristic of the reverse voltage can be utilized to quickly reduce the current to the holding current, and then the current can be kept at the holding current state through the holding voltage in the holding stage. Compared with the prior art, after the high-voltage excitation ends (i.e., it is considered that the solenoid valve is fully opened), the reverse voltage is immediately connected, so that the current is quickly reduced to the holding current, which not only reduces the average current magnitude within the working cycle, reduces the electromagnetic energy consumption, but also enables the solenoid valve to adapt to better opening and closing working conditions.

[0031] (4) In this patent, the duration of the turn-on stage is specified as follows: when the solenoid valve is in the 0-current state, the solenoid valve is excited by the high-voltage source until the time required to complete the stroke.

[0032] Generally, the dynamic characteristics of the solenoid valve are weak, while the current dynamic characteristics of its electromagnetic coil are good. In the prior art, such as in patent [CN201610015304.4], after increasing the current to the turn-on current, the high-voltage source is immediately switched to a lower steady voltage source. This will result in that due to the weak dynamic characteristics of the solenoid valve and the good current dynamic characteristics of its electromagnetic coil, when the coil current reaches the turn-on current, the valve is still in the opening motion state and has not completed the stroke. At this time, immediately switching the high-voltage source to a steady voltage source will reduce the driving force in the turn-on stage of the solenoid valve and reduce the dynamic characteristics in the turn-on stage of the solenoid valve. In this patent, the duration of stage 3 is specified as follows: when the solenoid valve is in the 0-current state, the solenoid valve is excited by the high-voltage source until the time required to complete the stroke. Because, if in the 0-current state, using this high voltage for excitation can fully open the valve, then, in the case of already having a certain preloaded current, the same excitation time will surely be able to fully open the valve (continuously using high-voltage excitation during this period can ensure the dynamic characteristics in its turn-on stage to the greatest extent).

[0033] (5) In the prior art, as in patent [CN201610015304.4], during the closing stage of the solenoid valve, a negative voltage is used to reduce the current to the closing current and then immediately switched to zero voltage. The drawback of this method is that when the dynamic characteristics of some switching valves are weak while the current dynamic characteristics of their electromagnetic coils are good, when the current drops to the closing current and the valve is in the closing motion state, if the negative voltage is switched to zero voltage at this time, the driving force during the closing stage of the solenoid valve will be reduced, thereby reducing the dynamic characteristics of the valve during the closing stage. In the closing stage of the present invention, a negative voltage source excitation is used to directly reduce the current to 0. Since the electromagnetic force generated at 0 current is the least, the driving force during the closing process is always maintained at the maximum value, and the valve closes the fastest.

[0034] (6) The multi-voltage source control method greatly shortens the time when the voltage is at a high level within one cycle, which can minimize the coil heating and extend the equipment life. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a schematic structural diagram of the 7-voltage source solenoid valve high-dynamic control system of the present invention;

[0036] Figure 2 is a control signal and current curve diagram of the present invention;

[0037] Figure 3 is the opening and closing characteristics of a solenoid valve driven by a single voltage;

[0038] Figure 4 is the opening and closing characteristics of a solenoid valve driven by the system and method of the present invention;

[0039] Figure 5 is the opening and closing characteristics of a solenoid valve in a comparative example without a reverse voltage source. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] The present invention will be further described below in conjunction with the accompanying drawings of the specification and specific embodiments.

[0041] As Figure 1 shown, the system of this embodiment includes a preloaded high voltage source 1, a preloaded stable voltage source 2, a high voltage source 3, a reverse voltage source 4, a stable voltage source 5, a negative voltage source 6, a zero voltage source 7, a high-speed switching switch 8, a current detector 9, a solenoid valve 10, a pressure sensing system 11, and a controller 12;

[0042] Among them, the controller 12 includes a control signal generation unit. The control signal 13 is generated by programming by the operator through the control signal generation unit inside the controller, and the control signal participates in the internal operation of the controller. The controller 12 real-time obtains the duty cycle, frequency, rising edge time, and falling edge time of the control signal generated by the control signal generation unit.

[0043] The high-speed switching switch 8 includes eight contact heads. Among them, the first contact head 8-1 is connected to the preloaded high-voltage source 1, the second contact head 8-2 is connected to the preloaded stable-voltage source 2, the third contact head 8-3 is connected to the high-voltage source 3, the fourth contact head 8-4 is connected to the reverse-voltage source 4, the fifth contact head 8-5 is connected to the stable-voltage source 5, the sixth contact head 8-6 is connected to the negative-voltage source 6, the seventh contact head 8-7 is connected to the zero-voltage source 7, and the eighth contact head 8-8 is connected to the current detector 9; the current detector 9 is connected to the coil of the solenoid valve 10, and the pressure sensing system 11 is connected to the solenoid valve to obtain the pressure states of each working port of the solenoid valve in real time; the controller 12 is connected to the pressure sensing system, and the controller 12 includes a control signal generation unit; the output port of the controller 12 is connected to the high-speed switching switch and can control the contact states of the eighth contact head 8-8 and the other 7 contact heads.

[0044] The controller obtains the data in the pressure sensing system in real time, so as to calculate the system turn-on current and turn-off current in the current state. The controller generates a control signal, that is, this control signal is generated by the controller itself and participates in operations such as internal calculation and digital triggering of the controller. For the convenience of explanation, Figure 1 the control signal is drawn outside the controller. This control signal is a square wave with adjustable frequency and duty cycle. Since this control signal is generated by the controller itself, the controller can also know the duty cycle, frequency, rising edge time, and falling edge time of the control signal in different states, and know when the rising edge of the control signal in the next cycle will arrive.

[0045] A single working cycle of the solenoid valve is divided into 7 stages, as Figure 2 shown, and are represented by the Arabic numerals 1-7 respectively. Among them, 1 represents the preloading excitation stage, 2 represents the preloading maintenance stage, 3 represents the turn-on stage, 4 represents the reverse excitation stage, 5 represents the maintenance stage, 6 represents the turn-off stage, and 7 represents the turn-off maintenance stage. The end time of stage 2 coincides with the rising edge time of the control signal, and the end time of stage 5 coincides with the falling edge of the control signal.

[0046] The controller generates a control signal. Before the rising edge of the control signal arrives, the controller calculates the time required to increase the coil current to the preloading current using the preloading excitation voltage according to the current coil current state and the parameters of the coil, and takes this time as the duration of the preloading excitation stage. According to the duration of the preloading excitation stage, the controller connects the eighth contact head to the first contact head in advance to enter stage 1. Under the action of the preloaded high-voltage source, the coil current will quickly reach the preloading current value. The voltage of the preloaded high-voltage source 1 is equal to the voltage of the high-voltage source 3. The preloading current is slightly less than the turn-on current.

[0047] Since the duration of Stage 1 is calculated by the controller based on the electrical parameters of the current coil, when the duration of Stage 1 ends, the current magnitude exactly reaches the preload start current. At this time, the duration of Stage 1 ends, and the controller controls the eighth contact to connect with the second contact to enter Stage 2. Under the action of the preload stable voltage source, the current is maintained at the preload current state reached after the end of Stage 1. The voltage magnitude of the preload stable voltage source is equal to the product of the preload start current and the coil resistance.

[0048] After Stage 2 ends, that is, when the rising edge of the control signal arrives, the controller controls the eighth contact to connect with the third contact to enter Stage 3. Under the excitation of the high voltage source, the current in the coil rises rapidly. Since the current has been stabilized at the preload current state slightly lower than the start current during the preload stage, the current in Stage 3 will rise to the start current in a very short time, and then the spool starts to move, and the solenoid valve enters the open stage. The high voltage source continues to be maintained, and the maintenance time is equal to the time required to excite the solenoid valve to complete the stroke with the described high voltage source when the solenoid valve is in the 0-current state;

[0049] After Stage 3 ends, the controller controls the eighth contact to connect with the fourth contact to enter Stage 4. The controller calculates the time required for the coil current to drop from the start current after the end of Stage 3 to the holding current (the holding current is slightly greater than the closing current) under the action of the reverse voltage source according to the current coil parameters and the coil current. This time is the duration of Stage 4.

[0050] Under the action of the reverse voltage source, the coil current drops rapidly and, at the end of Stage 4, reduces the current to the holding current state to keep the solenoid valve in the open state;

[0051] After Stage 4 ends, the controller controls the eighth contact to connect with the fifth contact to enter Stage 5. Since the duration of Stage 4 is calculated by the controller based on the electrical parameters of the current coil, when the duration of Stage 4 ends, the current magnitude exactly reaches the holding current. Under the action of the stable voltage source, the coil current is always stable at the current state after the end of Stage 4 to ensure that the solenoid valve remains in the closed state; (the magnitude of the stable voltage source is equal to the product of the holding current and the resistance);

[0052] After Stage 5 ends, that is, at the moment when the falling edge of the control signal arrives, the controller controls the eighth contact to connect with the sixth contact to enter Stage 6. Under the action of the negative voltage source, the current drops rapidly to the closing current. At this time, the solenoid valve starts to close, and the negative voltage source continues to excite until the current drops to 0. At this time, Stage 6 ends;

[0053] After the end of stage 6, the controller controls the eighth contact head to connect with the seventh contact head to enter stage 7. Under the action of the zero voltage source, the zero current state is always maintained in the coil until stage 1 of the next cycle arrives, and the system repeats the above process;

[0054] In the above scheme, the voltage value of the pre-loaded stable voltage source is slightly less than the product of the solenoid valve coil resistance and the opening current, generally less than 5% - 10% of the product of the solenoid valve coil resistance and the opening current. That is, when using the pre-loaded stable voltage source for excitation, when the current is stable, the current magnitude is less than 5% - 10% of the opening current, and the current magnitude at this time is the pre-loaded current; the voltage value of the stable voltage source is slightly greater than the product of the solenoid valve coil resistance and the closing current, generally greater than 5% - 10% of the product of the solenoid valve coil resistance and the closing current. That is, when using the stable voltage source for excitation, when the current is stable, the current magnitude is greater than 5% - 10% of the closing current, and the current magnitude at this time is the holding current.

[0055] The calculation process of the duration required for the pre-loading excitation stage (stage 1) in the above scheme is: the controller calculates the time required for the current in the coil to rise to the pre-loaded current according to the current drive voltage, solenoid valve current, wire inductance resistance and inductance, and takes it as the duration of stage 1;

[0056] The duration required for the pre-loading maintenance stage (stage 2) in the above scheme is: usually, the duration is 1 - 2 ms, and it can be appropriately increased or decreased according to different working conditions;

[0057] The calculation process of the duration required for the opening stage (stage 3) in the above scheme is: the high voltage duration is equal to the time required for the solenoid valve to complete the stroke when excited by the above-mentioned high voltage source in the 0 current state, that is, taken as the duration of stage 3; the start time of stage 3 is the moment when the rising edge of the control signal arrives. According to the moment when the rising edge of the control signal arrives, and the durations of stage 1 and stage 2, the controller automatically calculates the start and end times of stage 1 and stage 2.

[0058] The calculation process of the duration required for the reverse excitation stage (stage 4) in the above scheme is: the time required for the coil current after the end of stage 3 to drop to the holding current under the excitation of the reverse voltage source.

[0059] The calculation process of the duration required for the maintenance stage (stage 5) in the above scheme is: the time duration from the end time of stage 4 to the moment when the falling edge of the control signal arrives.

[0060] The calculation process of the duration required for the closing stage (stage 6) in the above scheme is: the time required for the holding current after the end of stage 5 to drop to 0 current under the excitation of the negative voltage source.

[0061] The calculation process for the duration required in the closing maintenance phase (phase 7) of the described solution is: the duration from the end moment of phase 6 to the start moment of the next phase 1.

[0062] As Figure 3 shown, it is a schematic diagram of the opening and closing characteristics of a solenoid valve driven by a single 24V voltage. It can be seen from the figure that after testing, the opening lag of this solenoid valve is 3ms, the opening movement is 2ms, the closing lag is 6.8ms, and the closing movement is 6.1ms.

[0063] As Figure 4 shown is a schematic diagram of the opening and closing characteristics of the solenoid valve controlled by the system and method of the present invention. In this embodiment, the voltages of the preloaded high voltage source 1, preloaded stable voltage source 2, high voltage source 3, reverse voltage source 4, stable voltage source 5, negative voltage source 6, and zero voltage source 7 are 24V, 8V, 24V, -24V, 5V, -24V, and 0V respectively; after testing, the opening lag is 0.2ms, the opening movement is 1.9ms, the closing lag is 0.1ms, and the closing movement is 1.7ms. As Figure 4 shown, when the coil current of the present invention arrives at the opening command signal, it has already stabilized in the preloaded current phase. In the opening phase, the high voltage excitation time is set to be equal to the time required to excite the solenoid valve to complete the stroke with the described high voltage source when the solenoid valve is in the 0 - current state, so as to ensure that the solenoid valve is fully opened. The present invention is designed with a reverse excitation phase. In the reverse excitation phase, a voltage value equal to the reverse voltage source of the high voltage source is used to quickly reduce the coil current to the holding current. This not only reduces the average current magnitude within the working cycle and reduces the electromagnetic energy consumption, but also enables the solenoid valve to better adapt to the opening and closing working conditions.

[0064] As Figure 5 shown is a comparative example without a reverse excitation phase. The working process of this comparative example is similar to that of this application, but it does not include a reverse excitation phase. The voltage sources of this comparative example include a preloaded high voltage source, a preloaded stable voltage source, a high voltage source, a stable voltage source, a negative voltage source, and a zero voltage source, with voltages of 24V, 8V, 24V, 5V, -24V, and 0V respectively. From Figure 4 and Figure 5 the comparison can be seen that by adding the reverse voltage source 4, the present invention greatly reduces the time for the coil current to drop to the holding current, and can better be applied to occasions with a higher control signal frequency.

Claims

1. A high-dynamic high-frequency response control system for a solenoid valve, characterized in that It includes a preloading high-voltage source (1), a preloading 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 switching switch (8), a current detector (9), a solenoid valve (10), a pressure sensing system (11) and a controller (12); The high-speed switching switch (8) has eight contact heads. Among them, the first contact head (8-1) is connected to the preloading high-voltage source (1), the second contact head (8-2) is connected to the preloading regulated-voltage source (2), the third contact head (8-3) is connected to the high-voltage source (3), the fourth contact head (8-4) is connected to the reverse-voltage source (4), the fifth contact head (8-5) is connected to the regulated-voltage source (5), the sixth contact head (8-6) is connected to the negative-voltage source (6), the seventh contact head (8-7) is connected to the zero-voltage source (7), and the eighth contact head (8-8) is connected to the current detector (9); the current detector (9) is connected to the coil of the solenoid valve (10), and the pressure sensing system (11) is connected to the solenoid valve to obtain the pressure state of each working port of the solenoid valve in real time; the controller (12) is connected to the pressure sensing system, and the controller (12) includes a control signal generation unit; the output port of the controller (12) is connected to the high-speed switching switch and can control the contact state between the eighth contact head (8-8) and the other 7 contact heads.

2. The solenoid valve high-dynamic high-frequency response control system according to claim 1, characterized in that The control signal generated by the control signal generation unit is a square-wave signal, and the duty cycle of the square-wave signal is the ratio of the target opening time of the solenoid valve to the cycle time.

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

4. A control method for the high-dynamic high-frequency response control system of the solenoid valve according to claim 1, characterized in that It includes the following steps: The controller generates a control signal. Before the rising edge of the control signal arrives, the controller calculates the time required to increase the coil current to the preloading current using the preloading excitation voltage according to the current coil current state and the parameters of the coil, and takes this time as the duration of the preloading excitation stage; According to the duration of the preloading excitation stage, the controller connects the eighth contact head to the first contact head in advance to enter the preloading excitation stage; under the action of the preloading high-voltage source, the coil current reaches the preloading current value; After reaching the preloading current value, the controller controls the eighth contact head to be connected to the second contact head to enter the preloading maintenance stage. Under the action of the preloading regulated-voltage source, the current is maintained at the preloading current state all the time; When the rising edge of the control signal arrives, the controller controls the eighth contact head to be connected to the third contact head to enter the opening stage. Under the excitation of the high-voltage source, the coil current rises rapidly, and then the spool starts to move, and the solenoid valve enters the opening stage; the high-voltage source continues to be maintained until it is ensured that the solenoid valve is fully opened; Then the controller controls the eighth contact head to be connected to the fourth contact head to enter the reverse excitation stage; the controller calculates the time required for the coil current to drop from the current after the end of the opening stage to the holding current under the action of the reverse-voltage source according to the coil parameters and the current coil current, and this time is the duration of the reverse excitation stage; Under the action of the reverse voltage source, the coil current drops rapidly, and the current decreases to a holding current state greater than a set ratio of the turn-off current to maintain the solenoid valve in the open state; After that, the controller controls the eighth contact to connect with the fifth contact to enter the holding stage. Under the action of the stable voltage source, the coil current remains stable at the holding current state to maintain the solenoid valve in the open state; When the falling edge of the control signal arrives, the controller controls the eighth contact to connect with the sixth contact to enter the closing stage. Under the action of the negative voltage source, the current drops rapidly to the turn-off current. At this time, the solenoid valve starts to close, and the negative voltage source continues to excite until the current decreases to 0; The controller controls the eighth contact to connect with the seventh contact to enter the closing holding stage. Under the action of the zero voltage source, zero current state is always maintained in the coil until the next cycle arrives.

5. The control method according to claim 4, wherein The voltage of the preloaded high voltage source (1) is equal to the voltage of the high voltage source (3), and the preloaded current is less than the set ratio of the turn-on current.

6. The control method according to claim 4, characterized in that The magnitude of the preloaded stable voltage source is equal to the product of the preloaded turn-on current and the coil resistance.

7. The control method according to claim 4, characterized in that The voltage value of the stable voltage source is greater than the product of the solenoid valve coil resistance and the turn-off current.

8. The control method according to claim 4, characterized in that The calculation process of the duration required for the preloaded excitation stage is as follows: The controller calculates the time required for the coil current to rise to the preloaded current based on the current solenoid valve current, coil resistance, and inductance, and uses it as the duration of the preloaded excitation stage.

9. The control method according to claim 4, characterized in that The duration of the preloaded holding stage is 1 - 2 ms.

10. The control method according to claim 4, characterized in that The duration of the turn-on stage is equal to the time required to excite the solenoid valve from the 0 current state to fully open using the high voltage source.

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