JP5381333B2 - Solenoid valve opening control device - Google Patents

Description

  The present invention relates to an opening control device for a solenoid driven valve.

Conventionally, a dither signal is superimposed on the drive current to suppress the effect of response hysteresis (hysteresis that occurs between the valve opening and closing directions on the drive current that flows through the solenoid coil) generated in a proportional solenoid valve such as a solenoid drive valve. A control method is adopted.
For example, in the following Patent Document 1, in a control device that digitally controls a proportional valve coil by an integrated amount of pulse width modulation current, a resistance is added to the output stage circuit in parallel with the proportional valve coil, A technique is disclosed in which the time constant is reduced to stabilize the proportional solenoid valve closing control and to follow the drive current corresponding to the dither waveform.

  Further, in Patent Document 2 below, an alternating current dither current is superimposed on a current flowing through an electromagnet, and the spool is swung with a small amplitude that does not affect the control hydraulic pressure, and the ratio between the current flowing and the solenoid force is in another region. A technique is disclosed in which the dither effect can be averaged over the entire control region by increasing the amplitude of the dither current in the control region smaller than that in the other control regions.

  Further, in Patent Document 3 below, a hysteresis at the time of operation of a proportional solenoid valve that operates according to a drive current energized to a solenoid coil is detected, and the detected hysteresis is determined to be equal to or greater than a first predetermined value. Sometimes the dither amplitude of the drive current is increased from the previous dither amplitude, and when it is determined that the detected hysteresis is equal to or smaller than the second predetermined value which is smaller than the first predetermined value, the dither amplitude of the drive current is increased from the previous dither amplitude. A technique for removing as much as possible the effect of hysteresis on the solenoid valve without reducing the durability and reliability of the solenoid valve by reducing the value is disclosed.

Japanese Patent Laid-Open No. 10-184972 Japanese Patent Laid-Open No. 11-202947 JP 2000-283325 A

  By the way, as the force acting on the plunger (movable iron core) of the solenoid drive valve, the suction force (force that attracts the plunger to the fixed iron core) generated by flowing the drive current to the solenoid coil and the reaction force (fixing the plunger) The force in the opening direction is controlled by increasing the suction force due to the drive current rather than the reaction force from the spring, and the suction force due to the drive current is made smaller than the reaction force due to the spring. It is common to perform valve control.

  As this spring, a spring with a relatively strong reaction force is used. Depending on the product, the response (valve opening relative to the drive current) may differ significantly between the valve control in the opening direction and the valve control in the closing direction. When the dither signal of the same level is superimposed on the drive current in the valve control in both the opening and closing directions, there is a problem that excessive response to the dither signal is exhibited and linear valve opening control becomes difficult.

 The present invention has been made in view of the above-described circumstances, and provides an opening control device for a solenoid-driven valve that maintains good response of the solenoid-driven valve and enables linear valve opening control. Objective.

In order to solve the above-described problems, an opening control device for a solenoid drive valve according to the present invention provides a solenoid drive valve that supplies a drive current in which a dither signal is superimposed on a drive coil provided in a solenoid drive valve to be controlled. The opening degree control device of the valve should be superimposed on the drive current in accordance with a valve control direction that is a direction for opening and closing the solenoid drive valve and a current position on a movable shaft of a movable iron core provided in the solenoid drive valve. A dither amplitude determining unit that determines an amplitude value of the dither signal is provided.

  In addition, the solenoid-operated valve opening control device according to the present invention includes a position sensor that detects a current position of the movable iron core on the movable shaft, a target position of the movable iron core that is input from an external control device, and the position sensor. A deviation calculation unit that calculates a deviation amount from the current position of the movable core detected by the PID calculation unit, and a PID calculation unit that calculates an operation amount by performing a PID calculation based on the deviation amount calculated by the deviation calculation unit A control direction determination unit that determines whether the valve control direction of the solenoid-driven valve is an open direction or a close direction based on the deviation amount calculated by the deviation calculation unit, and the control direction determination unit The dither signal amplitude value to be superimposed on the drive current is determined according to the determined valve control direction and the current position of the movable iron core detected by the position sensor. An amplitude determination unit, a dither signal generation unit that generates a dither signal having an amplitude value determined by the dither amplitude determination unit, an operation amount calculated by the PID calculation unit, and the dither signal generation unit An addition operation unit that adds the dither signal, a PWM signal generation unit that generates a PWM signal according to the addition result of the addition operation unit, and the drive coil according to the PWM signal generated by the PWM signal generation unit And a drive current generation unit that generates a drive current in which a dither signal to be supplied is superimposed.

Further, in the solenoid-operated valve opening control apparatus according to the present invention, the dither amplitude determining unit determines both a positive-side amplitude value and a negative-side amplitude value of a dither signal to be superimposed on the driving current. It is characterized by.
Furthermore, in the solenoid-operated valve opening control apparatus according to the present invention, the dither amplitude determining unit superimposes a drive current on the current position of the movable core in each of the opening direction and the closing direction of the valve control direction. Table data in which the + side amplitude value and the − side amplitude value of the dither signal to be set are set is stored in advance.

 According to the present invention, the amplitude value of the dither signal to be superimposed on the drive current is determined according to the valve control direction of the solenoid drive valve and the current position on the movable shaft of the movable iron core provided in the solenoid drive valve. Even when a spring having a strong reaction force is used for the drive valve, good responsiveness can be maintained in all control regions, and linear valve opening control can be performed.

It is a block block diagram of the solenoid valve control apparatus (opening control apparatus of a solenoid drive valve) C which concerns on one Embodiment of this invention. For each of the opening direction and the closing direction of the valve control direction stored in the dither amplitude determining unit C4 of the electromagnetic valve control device C according to the present embodiment, the driving current is set to the current position of the plunger S2 (movable iron core). It is an image figure of the table data in which the amplitude value on the + side and the amplitude value on the-side of the dither signal to be superimposed are set. It is operation | movement explanatory drawing of the solenoid valve control apparatus C which concerns on this embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram of a solenoid-operated valve opening control device C (hereinafter abbreviated as an electromagnetic valve control device) according to the present embodiment. In the following, the solenoid driven valve S will be described as an object to be controlled by the electromagnetic valve control device C according to the present embodiment. Further, in FIG. 1, only the solenoid coil (drive coil) S1, the plunger (movable iron core) S2, and the spring S3 are shown as components of the solenoid drive valve S for the sake of simplicity.

  In FIG. 1, the X axis represents the movable shaft of the plunger S2, and the suction force generated by supplying the solenoid coil S1 with the drive current I from the solenoid valve controller C (the plunger S2 is attracted to a fixed iron core (not shown). Force) and the reaction force of the spring S3 (force that pulls the plunger S2 away from the fixed iron core), the plunger S2 reciprocates on the X axis, thereby controlling the valve opening in the opening direction and the closing direction. In FIG. 1, the positive direction of the X-axis is the opening direction of the valve opening (the direction in which the spring S3 contracts), and the position X0 of the plunger S2 when the spring S3 is fully extended (hereinafter, this position is referred to as the reference position). The valve opening is “0”, that is, the valve is completely closed.

  As shown in FIG. 1, the solenoid valve control device C according to the present embodiment includes a deviation calculation unit C1, a PID calculation unit C2, a control direction determination unit C3, a dither amplitude determination unit C4, a dither signal generation unit C5, and an addition calculation unit. C6, a PWM (Pulse Width Modulation) signal generation unit C7, a switching element (drive current generation unit) C8, a position sensor (position sensor) C9, and a sensor input unit C10.

  The deviation calculation unit C1 is input from the host controller (not shown) on the movable shaft of the plunger S2 (corresponding to the target valve opening) and the position sensor C9 via the sensor input unit C10. The deviation amount ΔX (= Xp−Xs) of the plunger S2 from the current position Xs on the movable shaft is calculated, and the deviation amount ΔX, which is the calculation result, is output to the PID calculation unit C2 and the control direction determination unit C3. The target position Xp and the current position Xs are positions on the X axis starting from the reference position X0.

  The PID calculation unit C2 drives the drive current I so that the deviation amount ΔX input from the deviation calculation unit C1 becomes “0”, that is, the target position Xp on the movable shaft of the plunger S2 matches the current position Xs. An operation signal (operation amount) for generating the signal is calculated by PID calculation, and an operation signal as a result of the calculation is output to the addition calculation unit C6.

  The control direction determination unit C3 determines whether the valve control direction is the open direction or the close direction based on the sign of the deviation amount ΔX input from the deviation calculation unit C1, and outputs the determination result to the dither amplitude determination unit C4. Specifically, the control direction determination unit C3 determines that the valve control direction is the open direction when the deviation amount ΔX> 0, that is, the target position Xp> the current position Xs, and the deviation amount ΔX ≦ In the case of 0, that is, when the target position Xp ≦ the current position Xs, it is determined that the valve control direction is the closing direction.

 The dither amplitude determination unit C4 is configured to determine the valve control direction determination result input from the control direction determination unit C3 and the current position Xs on the movable shaft of the plunger S2 input from the position sensor C9 via the sensor input unit C10. Based on this, the positive-side amplitude value and the negative-side amplitude value of the dither signal to be superimposed on the drive current I are determined, and the determination result of these dither amplitude values is output to the dither signal generation unit C5.

  Specifically, as shown in FIG. 2, the dither amplitude determination unit C4 is configured so that the current position X1, X2, X3,..., Xn of the plunger S2 in each of the opening direction and the closing direction of the valve control direction (X1 Table data in which the + side amplitude value and the − side amplitude value of the dither signal to be superimposed on the drive current I with respect to <X2 <X3... <Xn) are stored in advance, and based on this table data Thus, the positive side of the dither signal corresponding to the determination result of the valve control direction input from the control direction determination unit C3 and the current position Xs of the plunger S2 input from the position sensor C9 via the sensor input unit C10. And the amplitude value on the negative side are determined.

 The dither signal generation unit C5 generates a dither signal having the dither amplitude value determined by the dither amplitude determination unit C4 and outputs the dither signal to the addition operation unit C6. The frequency of the dither signal is set in advance as a fixed value. The addition calculation unit C6 adds the operation signal input from the PID calculation unit C2 and the dither signal input from the dither signal generation unit C5, and outputs an addition signal as a result of the addition to the PWM signal generation unit C7. The PWM signal generation unit C7 generates a PWM signal having a duty ratio corresponding to the addition signal (that is, the addition signal of the operation signal and the dither signal) input from the addition calculation unit C6, and outputs the PWM signal to the switching element C8.

 The switching element C8 is, for example, a MOS-FET interposed between the power supply line Vcc and the solenoid coil S1, and is turned on / off according to the PWM signal input from the PWM signal generation unit C7. By such a switching operation based on the PWM signal of the switching element C8, a drive current I is generated and supplied to the solenoid coil S1 so that the current position Xs of the plunger S2 becomes the target position Xp and the above-described dither signal is superimposed. Is done.

  The position sensor C9 is, for example, an optical or magnetic position sensor, measures the current position (that is, the actual valve opening) on the movable shaft of the plunger S2, and uses the current position Xs as the measurement result as a sensor input unit. Output to C10. The sensor input unit C10 outputs the current position Xs on the movable shaft of the plunger S2 input from the position sensor C9 to the deviation calculation unit C1 and the dither amplitude determination unit C4.

  The above is the description regarding the configuration of the electromagnetic valve control device C according to the present embodiment. The deviation calculation unit C1, the PID calculation unit C2, the control direction determination unit C3, the dither amplitude determination unit C4, the dither signal generation unit C5, The addition operation unit C6 and the PWM signal generation unit C7 may be configured by analog circuits, or may be configured to realize the functions of the above-described components by software processing (digital processing) using a microprocessor. . When digital processing is used, since the current position Xs of the plunger S2 output from the position sensor C9 is an analog signal, it is necessary to provide an A / D converter that converts the analog signal into a digital signal.

  Next, the operation of the electromagnetic valve control device C according to the present embodiment configured as described above will be described in detail. Here, as shown in FIG. 3A, X4 is input from the host controller to the solenoid valve controller C as the target position Xp of the plunger S2, and the current position Xs of the plunger S2 on the movable shaft is X1 (X4>). Assuming that X1), the current position Xs of the plunger S2 measured by the position sensor C9 is X1, and the deviation amount ΔX calculated by the deviation calculator C1 is ΔX = X4−X1> 0.

  At this time, the PID calculation unit C2 generates an operation for generating the drive current I such that the deviation amount ΔX is “0”, that is, the current position on the movable shaft of the plunger S2 is changed from X1 to the target position X4. A signal (operation amount) is calculated and output to the addition operation unit C6. On the other hand, since the deviation amount ΔX> 0, the control direction determination unit C3 determines that the valve control direction is the open direction, and outputs the determination result to the dither amplitude determination unit C4.

  From the table data shown in FIG. 2, the dither amplitude determining unit C4 has a valve control direction of the open direction, and the amplitude value on the positive side and the negative side of the dither signal corresponding to the current position X1 on the movable shaft of the plunger S2. Determine the amplitude value. That is, at this time, the amplitude value on the + side of the dither signal is determined to be d1, and the amplitude value on the-side is determined to be d1 '. Then, the dither signal generation unit C5 generates a dither signal having the dither amplitude value determined by the dither amplitude determination unit C4 as described above, and outputs the dither signal to the addition operation unit C6.

  Thus, the dither signal having an amplitude value corresponding to the valve control direction and the current position of the plunger S2 and the operation signal for generating the drive current I so as to set the current position of the plunger S2 to the target position X4 are added. The signals are added by the unit C6 and output as an addition signal to the PWM signal generation unit C7, and a PWM signal corresponding to the addition signal is output from the PWM signal generation unit C7 to the switching element 8.

 As a result, the drive current I on which the dither signal (the dither signal having an amplitude value corresponding to the opening direction and the current position X1) is superimposed is applied to the solenoid coil S1 so that the current position of the plunger S2 becomes the target position X4. The suction force exceeding the reaction force of the spring S3 acts on the plunger S2 and starts moving toward the target position X4.

 FIG. 3B is an image diagram showing the state of the PID control described above. As shown in this figure, in the PID control, the current position Xs repeatedly increases or decreases with respect to the target position Xp of the plunger S2, and eventually coincides with the target position Xp. That is, when the current position Xs is below the target position Xp of the plunger S2, the valve control direction is the opening direction (deviation amount ΔX> 0). A positive-side amplitude value and a negative-side amplitude value of the dither signal corresponding to the current position of the plunger S1 are determined, and if the current position Xs exceeds the target position Xp of the plunger S2, valve control is performed. Since the direction is the closing direction (deviation amount ΔX ≦ 0), the amplitude value on the positive side and the negative side of the dither signal corresponding to the closing direction and the current position of the plunger S2 at that time are determined from the table data of FIG. Will do.

  As described above, according to the electromagnetic valve control device C according to the present embodiment, the amplitude value of the dither signal to be superimposed on the drive current I according to the valve control direction (opening direction, closing direction) and the current position of the plunger S2. Therefore, even when the spring S3 having a strong reaction force is used for the solenoid-operated valve S, good responsiveness can be maintained in all control regions, and linear valve opening control can be performed. It becomes.

In addition, this invention is not limited to the said embodiment, The following modifications are mentioned.
(1) In the above embodiment, the case where the dither signal is superimposed on the drive current I in all the control regions has been described. However, when the current position of the plunger S2 reaches near the target position (for example, within 2%). Since the influence of the hysteresis is reduced, the dither signal superposition may be controlled to stop.

(2) In the above embodiment, the + side amplitude value and the − side amplitude value of the dither signal to be superimposed on the drive current I according to the valve control direction (opening direction, closing direction) and the current position of the plunger S2. However, either one of the amplitude values may be determined, and the other amplitude value may be a fixed value.

(3) In the above embodiment, the case where the + side amplitude value and the − side amplitude value of the dither signal to be superimposed on the drive current I are determined using the table data as shown in FIG. For each of the valve control directions, an arithmetic expression indicating the relationship between the current position of the plunger S2 and the positive-side amplitude value and an arithmetic expression indicating the relationship between the current position of the plunger S2 and the negative-side amplitude value are stored in advance. In addition, the + side amplitude value and the − side amplitude value of the dither signal may be determined using these arithmetic expressions.

  C ... Solenoid valve control device, C1 ... Deviation calculation unit, C2 ... PID calculation unit, C3 ... Control direction determination unit, C4 ... Dither amplitude determination unit, C5 ... Dither signal generation unit, C6 ... Addition calculation unit, C7 ... PWM signal Generation unit, C8 ... switching element, C9 ... position sensor, C10 ... sensor input unit, S ... solenoid drive valve, S1 ... solenoid coil, S2 ... plunger, S3 ... spring

Claims (4)

An opening control device for a solenoid drive valve for supplying a drive current in which a dither signal is superimposed on a drive coil provided in a solenoid drive valve to be controlled,
A dither that determines an amplitude value of a dither signal to be superimposed on the drive current according to a valve control direction that is a direction for opening and closing the solenoid drive valve and a current position on a movable shaft of a movable iron core provided in the solenoid drive valve A solenoid-operated valve opening control device comprising an amplitude determining unit. A position sensor for detecting a current position on the movable shaft of the movable iron core;
A deviation calculating unit that calculates a deviation amount between a target position of the movable core input from an external control device and a current position of the movable core detected by the position sensor;
A PID calculation unit that calculates an operation amount by performing a PID calculation based on the deviation amount calculated by the deviation calculation unit;
A control direction determination unit that determines whether the valve control direction of the solenoid-driven valve is an open direction or a close direction based on the deviation amount calculated by the deviation calculation unit;
The dither amplitude determination for determining an amplitude value of a dither signal to be superimposed on the drive current according to the valve control direction determined by the control direction determination unit and the current position of the movable core detected by the position sensor. And
A dither signal generation unit for generating a dither signal having an amplitude value determined by the dither amplitude determination unit;
An addition calculation unit that adds the operation amount calculated by the PID calculation unit and the dither signal generated by the dither signal generation unit;
A PWM signal generation unit that generates a PWM signal according to the addition result of the addition operation unit;
A drive current generator for generating a drive current in which a dither signal supplied to the drive coil is superimposed according to the PWM signal generated by the PWM signal generator;
The opening control device for a solenoid driven valve according to claim 1, comprising:   3. The solenoid-operated valve according to claim 1, wherein the dither amplitude determining unit determines both a positive-side amplitude value and a negative-side amplitude value of a dither signal to be superimposed on the driving current. Opening control device.   The dither amplitude determining unit is configured to add a + side amplitude value and a − side amplitude value of a dither signal to be superimposed on a drive current with respect to a current position of the movable core in each of the opening direction and the closing direction of the valve control direction. 4. The solenoid-operated valve opening control device according to claim 3, wherein table data in which is set is stored in advance.

Images