JP7669072B2 - Method, system, device, program, recording medium for controlling a proportional solenoid valve, and proportional solenoid valve - Google Patents

Description

The present disclosure relates to a proportional solenoid valve used, for example, in a fuel gas control valve and the like, and a control technique for the same.

Valves are used to control fluids such as fuel gas, and a known example of this valve is a proportional solenoid valve that controls the valve opening by exciting a solenoid.
The opening degree of the proportional solenoid valve is controlled, for example, by a PWM (pulse width modulation) system.
Regarding the PWM control of this proportional solenoid valve, a control is known in which the period of dither vibration is increased or decreased in a suspension control device regardless of the magnitude of the current being supplied (Patent Document 1).

Japanese Patent Application Publication No. 10-258625

In a proportional solenoid valve, a difference occurs between the drive current when the drive current flowing through the solenoid is increased to reach a specific valve opening and the drive current when the drive current is decreased to reach a specific valve opening. Also, a difference occurs between the valve opening when the drive current is increased to reach a specific drive current and the valve opening when the drive current is decreased to reach a specific drive current. In other words, there is hysteresis between the drive current and the valve opening, and even with the same drive current, the valve opening differs depending on the direction of increase or decrease, and even with the same valve opening, the drive current differs.
When a proportional solenoid valve with such hysteresis characteristics is used, it affects the control of fluids such as fuel gas, and reduces the reliability of the control characteristics. The cause of this hysteresis is the magnetization characteristics of the proportional solenoid valve, particularly the residual magnetism. When using a magnetic material, the effect of this residual magnetism cannot be ignored.

When considering residual magnetism and solenoid excitation, there is an issue that when the proportional solenoid is excited in the same direction as the residual magnetism, the residual magnetism is added to the generated magnetic force, whereas when the proportional solenoid is excited in the opposite direction to the residual magnetism, part of the generated magnetic force is offset by the residual magnetism.
To address this issue, the inventor discovered that the effects of residual magnetism can be reduced by generating an alternating magnetic field in a proportional solenoid, and that the desired valve opening can be obtained by changing the level of the drive current that generates such an alternating magnetic field.
In view of the above problems and findings, an object of the present disclosure is to obtain a desired valve opening degree by controlling the level of the drive current while avoiding the effects of residual magnetism by generating an alternating magnetic field in a proportional solenoid.

In order to achieve the above object, according to one aspect of a control method for a proportional solenoid valve disclosed herein, the control method includes the steps of: generating a drive current; exciting a proportional solenoid in accordance with a current level of the drive current, and magnetizing a yoke and a movable magnetic pole to different magnetic poles by exciting the proportional solenoid regardless of the flow direction of the drive current; moving a valve body in a fixed direction by the attractive force of the movable magnetic pole and the magnetic pole generated in the yoke regardless of the flow direction of the drive current; and reversing the polarity of the drive current at a period faster than the movement of the valve body to generate an alternating magnetic field and offset at least the residual magnetism of the movable magnetic pole.
This control method for a proportional solenoid valve may include the steps of generating a forward pulse including a polarity reversal portion that reverses the polarity of the reverse drive current to a forward direction, generating a reverse pulse including a polarity reversal portion that reverses the polarity of the forward drive current to the reverse direction, controlling a duty ratio of the forward pulse excluding the polarity reversal portion, and controlling the duty ratio of the reverse pulse excluding the polarity reversal portion.

In order to achieve the above object, according to one aspect of the proportional solenoid valve system disclosed herein, the system includes a proportional solenoid valve in which a valve element is controlled by excitation of a proportional solenoid; a drive unit that generates a drive current to be passed through the proportional solenoid, excites the proportional solenoid in accordance with the current level of this drive current, and magnetizes a yoke and a movable magnetic pole to different magnetic poles by exciting the proportional solenoid regardless of the flow direction of the drive current; and a control unit that reverses the polarity of the drive current at a period faster than the movement of the valve element, which moves in a fixed direction due to the attractive force of the movable magnetic pole and the magnetic pole generated in the yoke, regardless of the flow direction of the drive current, to generate an alternating magnetic field and offset at least the residual magnetism of the movable magnetic pole.
This proportional solenoid valve system further includes a logic circuit that generates a forward pulse including a polarity reversal section that reverses the polarity of the reverse drive current to a forward direction, and generates a reverse pulse including a polarity reversal section that reverses the polarity of the forward drive current to the reverse direction, and a pulse width control section that controls the duty ratio of the forward pulse excluding the polarity reversal section or the duty ratio of the reverse pulse excluding the polarity reversal section.

In order to achieve the above object, according to one aspect of a proportional solenoid valve control device of the present disclosure, there is provided a proportional solenoid valve control device in which a valve element is controlled by excitation of a proportional solenoid, the control device comprising: a drive unit that generates a drive current to be passed through the proportional solenoid, excites the proportional solenoid in accordance with a current level of this drive current, and magnetizes a yoke and a movable magnetic pole to different magnetic poles by exciting the proportional solenoid regardless of the flow direction of the drive current ; and a control unit that generates an alternating magnetic field by reversing the polarity of the drive current at a period faster than the movement of the valve element, which moves in a fixed direction due to the attractive force of the movable magnetic pole and the magnetic pole generated in the yoke, regardless of the flow direction of the drive current, thereby canceling out at least the residual magnetism of the movable magnetic pole.
In this proportional solenoid valve control device, the control unit may further include a logic circuit that generates a forward pulse including a polarity reversing unit that reverses the polarity of the reverse drive current to a forward direction, and generates a reverse pulse including a polarity reversing unit that reverses the polarity of the forward drive current to the reverse direction, and a pulse width control unit that controls the duty ratio of the forward pulse excluding the polarity reversing unit or the duty ratio of the reverse pulse excluding the polarity reversing unit.

In order to achieve the above-mentioned object, according to one aspect of the program of the present disclosure, the program is realized by a computer, and has the following functions realized by the computer: generating control information for generating a drive current that excites a proportional solenoid; exciting the proportional solenoid in accordance with the current level of the drive current, and magnetizing the yoke and the movable magnetic pole to different magnetic poles by exciting the proportional solenoid regardless of the flow direction of the drive current ; and reversing the polarity of the drive current at a period faster than the movement of a valve body that moves in a fixed direction due to the attractive force of the magnetic pole generated in the movable magnetic pole and the yoke regardless of the flow direction of the drive current, thereby generating an alternating magnetic field and offsetting at least the residual magnetism of the movable magnetic pole.
In this program, the computer may further realize a function of generating a forward pulse including a polarity reversal section that reverses the polarity of the reverse drive current to a forward direction, a function of generating a reverse pulse including a polarity reversal section that reverses the polarity of the forward drive current to the reverse direction, a function of controlling a duty ratio of the forward pulse excluding the polarity reversal section, and a function of controlling the duty ratio of the reverse pulse excluding the polarity reversal section.
In order to achieve the above object, one aspect of a recording medium of the present disclosure is a computer-readable recording medium storing the program.

In order to achieve the above object, according to one aspect of the proportional solenoid valve disclosed herein, the proportional solenoid valve comprises a valve mechanism in which a valve element is controlled by excitation of a proportional solenoid; a drive unit that generates a drive current to be passed through the proportional solenoid, excites the proportional solenoid in accordance with the current level of this drive current, and magnetizes the yoke and the movable magnetic pole to different magnetic poles by excitation of the proportional solenoid regardless of the flow direction of the drive current; and a control unit that generates an alternating magnetic field by reversing the polarity of the drive current at a period faster than the movement of the valve element, which moves in a fixed direction due to the attractive force of the movable magnetic pole and the magnetic pole generated in the yoke regardless of the flow direction of the drive current , thereby offsetting at least the residual magnetism of the movable magnetic pole.

In order to achieve the above object, according to one aspect of the proportional solenoid valve disclosed herein, the proportional solenoid valve includes a valve mechanism, a proportional solenoid that controls the valve mechanism by excitation, a drive unit that excites the proportional solenoid in accordance with the current level of a drive current and magnetizes a yoke and a movable magnetic pole to different magnetic poles by excitation of the proportional solenoid regardless of the flow direction of the drive current, and a control unit that reverses the polarity of the drive current at a period faster than the movement of a valve body that moves in a fixed direction due to the attractive force of the magnetic poles generated in the movable magnetic pole and the yoke regardless of the flow direction of the drive current, and controls the valve opening degree according to the current level of the drive current.
In the proportional solenoid valve, the control unit may further include a logic circuit that generates a forward pulse including a polarity reversing unit that reverses the polarity of the reverse drive current to a forward direction, and generates a reverse pulse including a polarity reversing unit that reverses the polarity of the forward drive current to the reverse direction, and a pulse width control unit that controls a duty ratio of the forward pulse excluding the polarity reversing unit or a duty ratio of the reverse pulse excluding the polarity reversing unit.

According to the present disclosure, any of the following effects can be obtained.
(1) By reversing the polarity of the drive current passed through the solenoid, an alternating magnetic field is generated in the solenoid, and this alternating magnetic field can cancel out residual magnetism, thereby reducing hysteresis caused by residual magnetism.
(2) The valve opening can be controlled by the level of the drive current without being affected by residual magnetism.
(3) It is possible to reduce the difference between the drive current when the drive current flowing through the solenoid is increased to control it to a specific valve opening and the drive current when the drive current is decreased to control it to a specific valve opening.
(4) It is possible to reduce the difference between the valve opening degree when the drive current flowing through the solenoid is increased to reach a specific drive current and the valve opening degree when the drive current is decreased and controlled to a specific drive current.

FIG. 1 is a diagram showing a proportional solenoid valve system according to a first embodiment. FIG. 2 is a diagram showing a valve mechanism of a proportional solenoid valve. FIG. 2 is a diagram showing a valve drive mechanism of a proportional solenoid valve. 4 is a flowchart showing a control process of a proportional solenoid valve. 11A and 11B are diagrams illustrating polarity inversion, level control, and generation of attraction force of a drive current by PWM control. FIG. 13 is a diagram showing a proportional solenoid valve system according to a second embodiment. FIG. 13 is a diagram showing a proportional solenoid valve according to a third embodiment. FIG. 13 is a diagram showing the operating characteristics of a proportional solenoid valve driven by a drive current without polarity reversal. FIG. 13 is a diagram showing the operating characteristics of a proportional solenoid valve driven by a drive current with polarity reversal.

First Embodiment
Fig. 1 shows a proportional solenoid valve system 2 according to a first embodiment. The configuration shown in Fig. 1 is an example, and the present disclosure is not limited to such a configuration.
This proportional solenoid valve system 2 includes a proportional solenoid valve 4 and a control device 6. The proportional solenoid valve 4 is installed in a fluid path 8 through which a fluid G, such as fuel gas, flows. An inlet port 12-1 and an outlet port 12-2 are formed in a valve chamber 10. The fluid G flowing in the fluid path 8 is introduced into the valve chamber 10 from the inlet port 12-1, passes from the valve chamber 10 through a valve mechanism 14, and flows into the fluid path 8 from the outlet port 12-2. The flow direction of the fluid G shown by the arrow is merely one example.

The valve mechanism 14 includes a valve seat 16 and a valve element 18. The valve seat 16 is fixed to the wall surface of the valve chamber 10, and the valve element 18 moves in a direction perpendicular to the valve seat surface of the valve seat 16.
A diaphragm 24 is attached by a support member 22 to a shaft portion 20 formed on the central axis of the valve element 18. The outer edge of the diaphragm 24 is supported between the inner walls of the valve chamber 10. Therefore, the valve element 18 is supported by the diaphragm 24 so as to be able to move up and down in the valve chamber 10, and when the pressure of the fluid G acts on the inside of the valve chamber 10, the diaphragm 24 bulges and pulls the valve element 18 down.

A movable magnetic pole 26 is provided relative to the valve body 18, and this movable magnetic pole 26 is in contact with the shaft portion 20 of the valve body 18. In other words, the movable magnetic pole 26 constitutes a plunger. This movable magnetic pole 26 is inserted into a proportional solenoid 28 and is movable in the direction of the central axis of the valve body 18. A yoke 32 is provided in the proportional solenoid 28 with a coil 30 sandwiched therebetween. The coil 30 is wound around a coil bobbin 34 and provided in the proportional solenoid 28. Therefore, the yoke 32 constitutes a fixed magnetic pole relative to the movable magnetic pole 26.
A support frame 36 is fixed to the yoke 32 side, and a space 38 is formed in the support frame 36 to allow the diaphragm 24 to bulge.
A support member 40 is fixed to the yoke 32, and the support member 40 has a spring support portion 42. A spring insertion portion 44 is formed in the movable magnetic pole 26, and a coil spring 46 is installed between the spring insertion portion 44 and the spring support portion 42. Therefore, the restoring force of the spring 46 acts on the movable magnetic pole 26.

The control device 6 includes, for example, a drive unit 48 and a control unit 50, and generates a drive current id, inverts the polarity, and controls the level. The drive unit 48 generates a drive current id under the control of the control unit 50, and passes this drive current id to the proportional solenoid 28. The control unit 50 includes, for example, a computer, and receives detection outputs from various sensors such as a temperature sensor and a water volume sensor as a control signal Sin, and performs information processing for controlling the proportional solenoid valve 4. This information processing includes the following:
(a) Control for generating driving current i
(b) Reversal of polarity of the drive current id due to a period faster than the movement of the valve disc 18
(c) Control of the valve opening degree by the current level of the drive current id.

<Valve mechanism 14>
2 shows an enlarged view of the valve mechanism 14 of the proportional solenoid valve 4. The valve seat 16 is fixed to the valve chamber 10 by a retaining frame 51, and the gap between the valve seat 16 and the inner wall surface of the valve chamber 10 is sealed by an O-ring 52.
The valve body 18 has a conical surface portion 54, and this conical surface portion 54 and a valve opening portion 56 of the valve seat 16 perform a valve function.
In the valve chamber 10, a circular recess 58, for example, is formed on the central axis of the valve disc 18, facing the valve disc 18. In the valve chamber 10, a protrusion 60 is formed on the large-diameter surface of the valve disc 18, facing the recess 58. When the valve disc 18 moves, the protrusion 60 enters the recess 58 on the valve chamber 10 side, allowing the valve disc 18 to move.

<Valve Drive Mechanism 62 and Generation of Suction Force F>
3 shows a valve drive mechanism 62 of the proportional solenoid valve 4. The valve drive mechanism 62 drives the valve element 18 in the vertical direction when excited by a drive current id.
When a drive current id flows through the proportional solenoid 28, a magnetic field φ is generated in the proportional solenoid 28. This magnetizes the movable magnetic pole 26 and the yoke 32 (fixed magnetic pole), and different magnetic poles N and S are generated in the movable magnetic pole 26 and the yoke 32, and the movable magnetic pole 26 receives an attractive force F due to these magnetic poles N-S, and moves in the direction of the attractive force F. Regardless of the direction of the drive current id, different magnetic poles N and S are generated in the movable magnetic pole 26 and the yoke 32, and therefore an attractive force F due to the magnetic poles N-S acts.

<Polarity Reversal of Drive Current id>
When the polarity of the drive current id is reversed at regular intervals, the polarity of the magnetic poles N and S of the movable magnetic pole 26 and the yoke 32 is reversed, but an attractive force F acts between them in the same direction. As a result, a valve opening degree according to the current level of the drive current id can be obtained regardless of the polarity.
When the drive current id is reversed, the magnetization direction of the movable magnetic pole 26 and the yoke 32 is reversed, so that the residual magnetism is offset by the reversed current, and the influence of the residual magnetism can be eliminated.

<Control process of proportional solenoid valve 4>
4A shows an example of a control process for the proportional solenoid valve 4. This control process includes generating a drive current id (S101), inverting the polarity of the drive current id (S102), and controlling the current level of the drive current id (S103).
Generation of driving current id (S101): The control device 6 generates a driving current id to be flowed through the proportional solenoid 28.
Reversing polarity of drive current id (S102): The control device 6 reverses the polarity of the drive current id at a period faster than the moving speed of the valve disc 18. The movement of the valve disc 18 depends on fluctuations in the current level of the drive current id, and the polarity of the drive current id is reversed at a period faster than the moving speed of the valve disc 18, for example, at a period that is ½ the dither period Td.
Current level control of drive current id (S103): The control device 6 controls the current level of the drive current id, and controls the valve mechanism 14 to a valve opening degree according to the current level.

4B shows an example of polarity inversion and level control of the drive current id in this control process, which includes input of a control signal Sin (S201), calculation of a duty ratio of a forward pulse (S202), calculation of a duty ratio of a reverse pulse (S203), generation of a forward pulse (execution of pulse control based on the calculated duty ratio) (S204), generation of a reverse pulse (execution of pulse control based on the calculated duty ratio) (S205), control of the valve opening (S206), etc.
Input of control signal Sin (S201): The control device 6 receives a control signal Sin for controlling the valve opening degree of the valve mechanism 14. The valve opening degree is controlled by the signal level of this control signal Sin.

Calculation of Duty Ratio of Forward Pulse (S202): The control device 6 calculates the duty ratio of the forward pulse excluding the polarity control pulse Psw1 (polarity reversal portion) described later.
Calculation of Duty Ratio of Reverse Pulse (S203): The control device 6 calculates the duty ratio of the reverse pulse excluding the polarity control pulse Psw2 (polarity reversal portion) described later.

Generation of forward pulse (execution of pulse control with calculated duty ratio) (S204): The control device 6 generates a forward pulse for generating a forward drive current id to be passed through the proportional solenoid 28. This forward pulse includes a polarity control pulse Psw1 at the beginning as a polarity reversal portion for reversing the current direction of the drive current id faster than the movement of the valve body 18. This polarity control pulse Psw1 has a larger pulse width than the other forward pulses, and is a high duty ratio pulse. The polarity reversal portion in the forward pulse is used to switch the polarity of the reverse drive current id to the forward drive current id.
Generation of reverse pulse (execution of pulse control with calculated duty ratio) (S205): The control device 6 generates a reverse pulse for generating a reverse drive current id to be passed through the proportional solenoid 28. This reverse pulse includes a polarity control pulse Psw2 at the beginning as a polarity reversal portion for reversing the current direction of the drive current id faster than the movement of the valve body 18. This polarity control pulse Psw2 has a larger pulse width than the other reverse pulses, and is a high duty ratio pulse. The polarity reversal portion in the reverse pulse is used to switch the polarity of the forward drive current id to the reverse drive current id.
Control of valve opening degree (S206): The control device 6 controls the current level of the drive current id in accordance with the signal level of the control signal Sin, thereby controlling the valve opening degree.

<Polarity Reversal of Drive Current id, Its Level Control, and Attraction Force F>
5A shows a forward PWM pulse, which is an example of a forward pulse. This forward pulse is generated for a period of 1/2 the dither period Td (=Td/2), and includes a polarity control pulse Psw1 as a polarity reversal part at the beginning. The polarity control pulse Psw1 has a constant pulse width in order to shorten the polarity reversal period in which the reverse drive current id is switched to the forward current.
On the other hand, the duty ratio of the forward PWM pulses excluding the polarity control pulse Psw1 is controlled by the control signal Sin. For convenience of explanation, the duty ratio is set to a constant value in A of Fig. 5, but the duty ratio is controlled to a different value depending on the valve opening degree.

FIG. 5B shows a reverse PWM pulse, which is an example of a reverse pulse. This reverse pulse is generated for a period of 1/2 the dither period Td (=Td/2), and includes a polarity control pulse Psw2 as a polarity reversal part at the beginning. The polarity control pulse Psw2 has a constant pulse width in order to shorten the polarity reversal period in which the forward drive current id is switched to the reverse direction. In this embodiment, the polarity control pulses Psw1 and Psw2 have the same pulse width.
On the other hand, the duty ratio of the reverse PWM pulses excluding the polarity control pulse Psw2 is controlled by the control signal Sin. For convenience of explanation, the duty ratio is set to a constant value in B of Fig. 5, but the duty ratio is controlled to a different value depending on the valve opening degree.

5C shows the driving current id flowing in the forward or reverse direction. The driving current id is repeatedly switched from the reverse driving current id to the forward driving current id and further from the forward driving current id to the reverse driving current id by alternately generating a polarity control pulse Psw1 and a polarity control pulse Psw2 every half of the dither period Td.
The drive current id with this polarity reversal depends on the duty ratio of the forward PWM pulse or the reverse PWM pulse, and the current level is controlled.

D in FIG. 5 shows the attractive force F acting on the movable magnetic pole 26 and the yoke 32 (fixed magnetic pole). The proportional solenoid 28 is excited by a drive current id with polarity reversal and level control, magnetizing the movable magnetic pole 26 and the yoke 32. The magnetic poles are reversed to a different pair every half of the dither period Td, and the attractive force F generated between the movable magnetic pole 26 and the yoke 32 depends on the level of the drive current id.

Effects of the First Embodiment
According to the first embodiment, any one of the following effects can be obtained.
(1) The polarity of the drive current id is reversed at half the dither period Td (=Td/2) to reverse the magnetic pole between the movable magnetic pole 26 and the yoke 32 by the proportional solenoid 28, thereby canceling out residual magnetism. This polarity reversal is performed at a period faster than the opening and closing of the valve mechanism 14, so it does not affect the control of the valve opening.
(2) During the time interval between polarity reversals, the current level of the drive current id is controlled by the duty ratio of the forward PWM pulse or the reverse PWM pulse. Therefore, the valve opening of the valve mechanism 14 can be controlled by the current level of the drive current id without being affected by the polarity reversal of the drive current id.

Second Embodiment
Fig. 6 shows a proportional solenoid valve system 2 according to a second embodiment. In the configuration of Fig. 6, the same parts as those in Fig. 1 are denoted by the same reference numerals.
The driving section 48 includes a power supply 64, a driving bridge circuit 66, a forward driving circuit 68-1, and a reverse driving circuit 68-2. The power supply 64 constitutes a current source for a driving current id.
The drive bridge circuit 66 includes Pch-FETs (P-channel field effect transistors) 71 and 72 and Nch-FETs (N-channel field effect transistors) 73 and 74 .

The forward drive circuit 68-1 receives a forward PWM pulse from the control unit 50 and passes a forward drive current id from the drive bridge circuit 66 to the proportional solenoid 28. In contrast, the reverse drive circuit 68-2 receives a reverse PWM pulse from the control unit 50 and passes a reverse drive current id from the drive bridge circuit 66 to the proportional solenoid 28. In other words, in a half cycle (= Td/2) of the dither cycle Td, the forward drive current id flows to the proportional solenoid 28 due to the conduction of the Pch-FET 72 and Nch-FET 73, and in the next half cycle (= Td/2) of the dither cycle Td, the reverse drive current id flows to the proportional solenoid 28 due to the conduction of the Pch-FET 71 and Nch-FET 74.

The control unit 50 includes a control circuit 76, a pulse generating unit 78, a PWM generating unit 80, and a logic circuit 82. The control circuit 76 is configured by a microcomputer, and includes a processor 84, a storage unit 86, and an input/output unit (I/O) 88. The processor 84 executes a control program stored in the storage unit 86, and performs control such as pulse width control in response to a control signal Sin.
Such control and control information includes:
a) Control information for generating the drive current id; b) Control information for reversing the polarity of the drive current id at a period faster than the movement of the valve body 18; c) Control information for controlling the valve opening degree by the current level of the drive current id; d) Calculation of the duty ratio of the forward pulse excluding the polarity control pulse; e) Calculation of the duty ratio of the reverse pulse excluding the polarity control pulse; f) Generation of a forward pulse including a control pulse for switching the polarity of the reverse drive current id to the forward direction (execution of the calculated pulse control).
g) Generation of a reverse pulse including a control pulse for switching the polarity of the forward drive current id to the reverse direction (execution of the calculated pulse control)
Includes:

The storage unit 86 is an example of a recording medium that stores the program of the present disclosure. The storage unit 86 uses memory elements such as a read-only memory (ROM), a random-access memory (RAM), and an electrically erasable programmable read-only memory (EEPROM) to generate and store various types of control information.
The I/O 88 receives the control signal Sin and generates control information.
The pulse generating section 78 generates a clock pulse with a constant period, and generates a pulse with a constant period by dividing or doubling the frequency of this clock pulse.

The PWM generating unit 80 has a forward PWM pulse generating function and a reverse PWM pulse generating function, generates a forward PWM pulse or a reverse PWM pulse having a duty ratio according to the signal level of the control signal Sin, and outputs it to a logic circuit 82.
The logic circuit 82 receives a control pulse synchronized with a half period of the dither period Td from the pulse generating unit 78, and outputs a forward PWM pulse and a reverse PWM pulse synchronized with Td/2. The forward PWM pulse is provided to the forward drive circuit 68-1, and the reverse PWM pulse is provided to the reverse drive circuit 68-2.

<Advantages of the Second Embodiment>
According to the second embodiment, any one of the following effects can be obtained.
(1) The polarity of the drive current id is reversed at half the dither period Td (=Td/2) to reverse the magnetic pole between the movable magnetic pole 26 and the yoke 32 by the proportional solenoid 28, thereby canceling out residual magnetism and improving the hysteresis characteristics.
(2) During the time interval of polarity reversal, the current level of the drive current id can be controlled by the duty ratio of the forward PWM pulse or the reverse PWM pulse. This makes it possible to improve the controllability of the valve opening of the valve mechanism 14 by the current level of the drive current id without being affected by the polarity reversal of the drive current id.

Third embodiment
7 shows a proportional solenoid valve 404 according to a third embodiment. In the configuration of FIG. 7, the same parts as those in FIG.
In this third embodiment, a proportional solenoid valve body 400 is the valve function portion of the proportional solenoid valve 4 in the first embodiment.
A proportional solenoid valve body 400, a drive unit 48, and a control unit 50 are installed in a housing 402. Therefore, in this embodiment, a proportional solenoid valve 404 having an integrated control function is configured.

[Experimental Results]
FIG. 8, with time on the horizontal axis and valve opening on the vertical axis, shows the operating characteristics of the proportional solenoid valves 4, 404 driven by a drive current id without polarity switching.
When the proportional solenoid 28 is excited by a drive current id that does not involve polarity reversal, the effect of residual magnetism cannot be eliminated because the drive current id is unidirectional. In other words, the magnetization is emphasized by a drive current id that is in the same direction as the residual magnetism, whereas the magnetization by the drive current id is impaired by a drive current id that is in the opposite direction to the residual magnetism, due to the offset of the residual magnetism. As a result, the effect of hysteresis h between the control signal Sin and the valve opening becomes significant.

FIG. 9 similarly shows the operating characteristics of the proportional solenoid valves 4, 404 driven by a drive current id with polarity switching, with the horizontal axis representing time and the vertical axis representing the valve opening.
When the proportional solenoid 28 is excited by a drive current id accompanied by polarity reversal, the residual magnetism is offset by the drive current id due to the polarity reversal, and a relationship between the drive current id and the valve opening degree that is not affected by the residual magnetism is obtained. As a result, the effect of the hysteresis h between the control signal Sin and the valve opening degree is improved to a negligible level.

Other Embodiments
(1) In the above embodiment, PWM control is used as an example. However, the proportional solenoid valve may be controlled by a method other than PWM control.
(2) The inversion period of the drive current id is set to half the dither period Td, but it need only be faster than the moving speed of the valve disc 18 and is not limited to the period in the embodiment.
(3) In the above embodiment, the polarity control pulse is illustrated as an example in the polarity reversal portion included in the forward pulse or reverse pulse, but this polarity control pulse may be a pulse generated by PWM control or a polarity reversal pulse generated separately from PWM control. This polarity reversal pulse may have a period including an optimal polarity reversal timing for reversing the polarity of the drive current id, and may have a pulse width set to an optimal time width.

As described above, the most preferred embodiment of the configuration of the present invention has been described. The present invention is not limited to the above description, and various modifications and changes can be made by those skilled in the art based on the gist of the invention described in the claims or disclosed in the description for carrying out the invention. It goes without saying that such modifications and changes are included in the scope of the present invention.

According to the present invention, the magnetic pole relationship between the movable magnetic pole and the fixed magnetic pole (yoke) can be reversed by the drive current, thereby canceling out residual magnetism, and the valve mechanism can be driven by a magnetic force that is not affected by residual magnetism, thereby improving hysteresis characteristics.

2 Proportional solenoid valve system 4, 404 Proportional solenoid valve 6 Control device G Fluid 8 Fluid path 10 Valve chamber 12-1 Inlet port 12-2 Outlet port 14 Valve mechanism 16 Valve seat 18 Valve body 20 Shaft portion 22 Support member 24 Diaphragm 26 Movable magnetic pole 28 Proportional solenoid 30 Coil 32 Yoke 34 Coil bobbin 36 Support frame 38 Space portion 40 Support member 42 Spring support portion 44 Spring insertion portion 46 Spring 48 Drive portion 50 Control portion 51 Holding frame 52 O-ring 54 Conical surface portion 56 Valve opening portion 58 Convex portion 60 Convex portion 62 Valve drive mechanism 64 Power source 66 Drive bridge circuit 68-1 Forward drive circuit 68-2 Reverse drive circuit 71, 72 Pch-FET
73, 74 Nch-FET
76 Control circuit 78 Pulse generating unit 80 PWM generating unit 82 Logic circuit 84 Processor 86 Storage unit 88 Input/output unit (I/O)
400 Proportional solenoid valve body 402 Housing

Claims (12)

generating a drive current;
a step of magnetizing a proportional solenoid in response to a current level of the driving current, and magnetizing a yoke and a movable magnetic pole to different magnetic poles by the excitation of the proportional solenoid regardless of a flow direction of the driving current;
a step of moving a valve body in a fixed direction by an attractive force of the magnetic poles generated between the movable magnetic pole and the yoke regardless of a flow direction of the drive current;
a step of generating an alternating magnetic field by inverting the polarity of the drive current at a period faster than the movement of the valve body, thereby canceling out at least the residual magnetism of the movable magnetic pole;
1. A method for controlling a proportional solenoid valve, comprising: generating a forward pulse including a polarity reversal portion that reverses the polarity of the driving current in a reverse direction to a forward direction;
generating a reverse pulse including a polarity reversal portion that reverses the polarity of the forward driving current to a reverse direction;
controlling a duty ratio of the forward pulse excluding a polarity reversal portion;
controlling a duty ratio of the reverse pulse excluding the polarity reversal portion;
2. The method of claim 1, further comprising: a proportional solenoid valve in which a valve element is controlled by excitation of a proportional solenoid;
a drive unit that generates a drive current to be passed through the proportional solenoid, excites the proportional solenoid in accordance with a current level of the drive current, and magnetizes the yoke and the movable magnetic pole to different magnetic poles by the excitation of the proportional solenoid regardless of the flow direction of the drive current;
a control unit that generates an alternating magnetic field by reversing the polarity of the drive current at a period faster than the movement of the valve body, which moves in a fixed direction by the attractive force of the magnetic pole generated between the movable magnetic pole and the yoke regardless of the flow direction of the drive current, thereby canceling out at least the residual magnetism of the movable magnetic pole;
A proportional solenoid valve system comprising: a logic circuit that generates a forward pulse including a polarity reversal section that reverses the polarity of the driving current in the reverse direction to a forward direction, and generates a reverse pulse including a polarity reversal section that reverses the polarity of the driving current in the forward direction to a reverse direction;
a pulse width control section that controls a duty ratio of the forward pulse excluding a polarity reversal section, or a duty ratio of the reverse pulse excluding a polarity reversal section;
4. The proportional solenoid valve system of claim 3, further comprising: A control device for a proportional solenoid valve in which a valve element is controlled by energizing a proportional solenoid,
a drive unit that generates a drive current to be passed through the proportional solenoid, excites the proportional solenoid in accordance with a current level of the drive current, and magnetizes the yoke and the movable magnetic pole to mutually different magnetic poles by the excitation of the proportional solenoid regardless of a flow direction of the drive current;
a control unit that generates an alternating magnetic field by reversing the polarity of the drive current at a period faster than the movement of the valve body, which moves in a fixed direction due to the attractive force of the magnetic pole generated between the movable magnetic pole and the yoke regardless of the flow direction of the drive current, thereby canceling out at least the residual magnetism of the movable magnetic pole;
A control device for a proportional solenoid valve comprising: The control unit further includes a logic circuit that generates a forward pulse including a polarity reversal unit that reverses the polarity of the reverse driving current to a forward direction, and generates a reverse pulse including a polarity reversal unit that reverses the polarity of the forward driving current to a reverse direction;
a pulse width control section that controls a duty ratio of the forward pulse excluding a polarity reversal section, or a duty ratio of the reverse pulse excluding a polarity reversal section;
6. The control device for a proportional solenoid valve according to claim 5, further comprising: A program implemented by a computer,
A function of generating control information for generating a drive current for exciting the proportional solenoid;
a function of exciting the proportional solenoid in response to a current level of the driving current, and magnetizing the yoke and the movable magnetic pole to different magnetic poles by the excitation of the proportional solenoid regardless of the flow direction of the driving current;
A function of generating an alternating magnetic field by reversing the polarity of the driving current at a period faster than the movement of the valve body which moves in a fixed direction by the magnetic pole attraction force generated between the movable magnetic pole and the yoke regardless of the flow direction of the driving current, thereby canceling out at least the residual magnetism of the movable magnetic pole;
A program for realizing the above by the computer. Further, a function of generating a forward pulse including a polarity reversal portion that reverses the polarity of the driving current in the reverse direction to a forward direction;
A function of generating a reverse direction pulse including a polarity reversal portion that reverses the polarity of the forward driving current to a reverse direction;
A function of controlling the duty ratio of the forward pulse excluding the polarity reversal portion;
A function of controlling the duty ratio of the reverse pulse excluding the polarity reversal portion;
The program according to claim 7, which is implemented by the computer. A computer-readable recording medium storing the program according to claim 7 or 8. a valve mechanism in which a valve body is controlled by excitation of a proportional solenoid;
a drive unit that generates a drive current to be passed through the proportional solenoid, excites the proportional solenoid in accordance with a current level of the drive current, and magnetizes the yoke and the movable magnetic pole to mutually different magnetic poles by the excitation of the proportional solenoid regardless of a flow direction of the drive current;
a control unit that generates an alternating magnetic field by reversing the polarity of the drive current at a period faster than the movement of the valve body, which moves in a fixed direction due to the attractive force of the magnetic pole generated between the movable magnetic pole and the yoke regardless of the flow direction of the drive current, thereby canceling out at least the residual magnetism of the movable magnetic pole;
A proportional solenoid valve comprising: A valve mechanism;
a proportional solenoid for controlling the valve mechanism by excitation;
a driving unit that excites the proportional solenoid in response to a current level of a driving current and magnetizes the yoke and the movable magnetic pole to different magnetic poles by the excitation of the proportional solenoid regardless of the flow direction of the driving current;
a control unit that reverses the polarity of the drive current at a period faster than the movement of the valve body, which moves in a fixed direction by the attractive force of the magnetic poles generated between the movable magnetic pole and the yoke regardless of the flow direction of the drive current, and controls the valve opening degree according to the current level of the drive current;
A proportional solenoid valve comprising: The control unit further includes a logic circuit that generates a forward pulse including a polarity reversal unit that reverses the polarity of the reverse driving current to a forward direction, and generates a reverse pulse including a polarity reversal unit that reverses the polarity of the forward driving current to a reverse direction;
a pulse width control section that controls a duty ratio of the forward pulse excluding a polarity reversal section, or a duty ratio of the reverse pulse excluding a polarity reversal section;
12. A proportional solenoid valve as claimed in claim 10 or 11, comprising:

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