JP2018093044A - Solenoid valve driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solenoid valve driving device capable of reducing residual magnetic flux after solenoid valve driving as much as possible.SOLUTION: A solenoid valve driving device 2 includes a boosting circuit 3 that boosts from DC power supply VB, and a control circuit 20 turns on MOSFETs 8 and 9 at the initial stage of energization to energize a coil 1a of an electromagnetic valve 1 in the forward direction. After that, the control circuit 20 turns off the MOSFET 8 and intermittently turn on and off the MOSFET 11 to energize in the positive direction from the DC power source VB. After that, The MOSFETs 13 and 14 are turned on and reversely energized for a preset time Ton that has been set to the coil 1a in advance. Therefore, the residual magnetic flux generated by energizing the electromagnetic valve 1 in the positive direction can be demagnetized in a short time.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a solenoid valve driving device.

  In the solenoid valve driving device, direct current is supplied to the coil of the solenoid valve to control the opening of the valve, and the valve is closed by stopping the current supply. In this case, in order to improve the responsiveness of the opening of the solenoid valve, there is a type in which a booster circuit is provided to apply a voltage boosted by the booster circuit when the valve is opened.

  However, in such a solenoid valve drive device, there is a problem of residual magnetic flux generated in the solenoid valve in a state where energization is stopped after the solenoid valve is driven. The residual magnetic flux of the solenoid valve is canceled after a certain period of time. However, if the drive is attempted without waiting for this time, the current waveform at the time of driving is disturbed due to the influence of the residual magnetic flux, and the accuracy of driving the solenoid valve may be reduced. is there.

JP 2001-15332 A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electromagnetic valve driving device that can quickly demagnetize the residual magnetic flux after driving the electromagnetic valve.

  The electromagnetic valve driving device according to claim 1 is a control that controls driving by energizing the positive electrode terminal and the negative electrode terminal of the electromagnetic valve in a positive direction from a DC power source via the first switching element and the second switching element, respectively. A solenoid valve driving device having a circuit, wherein a diode is connected in reverse parallel and the positive terminal of the solenoid valve is connected to the negative side, and a diode is connected in reverse parallel and the negative terminal of the solenoid valve is connected to the positive terminal. A fourth switching element connected to the side, and the third switching element and the fourth switching element are driven by the control circuit in an off state of the first and second switching elements.

  By adopting the above configuration, when the electromagnetic valve is driven, the control circuit drives the first switching element and the second switching element to energize in the positive direction between the positive terminal and the negative terminal of the electromagnetic valve. As a result, the coil of the solenoid valve is energized in the positive direction, and the solenoid valve can be driven. At this time, a residual magnetic flux is generated in the coil of the solenoid valve after energization. On the other hand, the residual magnetic flux can be made zero by driving the third switching element and the fourth switching element and energizing the solenoid valve in the reverse direction by the control circuit. As a result, without waiting for the time until the residual magnetic flux of the coil disappears after the energization of the solenoid valve in the positive direction is completed, the solenoid valve can be demagnetized quickly and the solenoid valve can be accurately controlled again. Become.

Electrical configuration diagram showing the first embodiment Time chart of solenoid valve current and each drive signal Action explanatory diagram showing the current path when a reverse current flows through the solenoid valve Time chart showing the relationship between solenoid valve current and solenoid valve magnetic flux Electrical configuration diagram showing the second embodiment Time chart of solenoid valve current and each drive signal Electrical configuration diagram showing the third embodiment

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
The electromagnetic valve 1 is driven to open by applying a direct current to the coil 1a, and includes a positive terminal A and a negative terminal B. The solenoid valve 1 is energized and controlled by a solenoid valve driving device 2. The electromagnetic valve drive device 2 energizes the electromagnetic valve 1 using, for example, a 12V on-board battery as a DC power supply VB. In addition, the electromagnetic valve driving device 2 is provided with a booster circuit 3 that supplies a voltage higher than the voltage of the DC power supply VB in order to improve the responsiveness of the opening of the electromagnetic valve 1.

  In the booster circuit 3, a series circuit of a booster coil 4 and an N-channel type MOSFET 5 is connected between a DC power supply VB and the ground. A diode 5a is connected to the MOSFET 5 in antiparallel. The diode 5a may be built in the MOSFET 5 or provided externally. A common connection point between the booster coil 4 and the MOSFET 5 is connected to one end of the capacitor 7 through the diode 6 in the forward direction. One end of the capacitor 7 is an output terminal C, and the other end is connected to the ground.

  The output terminal C of the booster circuit 3 is connected to the positive terminal A of the solenoid valve 1 through an N-channel MOSFET 8. A diode 8a is connected to the MOSFET 8 in antiparallel. The negative terminal B of the electromagnetic valve 1 is connected to the ground via an N-channel MOSFET 9 as a second switching element and a current detection resistor 10. A diode 9a is connected to the MOSFET 9 in antiparallel. A DC power source VB is connected to the positive terminal A of the solenoid valve 1 via an N-channel MOSFET 11 and a diode 12 as a first switching element. A diode 11a is connected to the MOSFET 11 in antiparallel.

  The positive terminal A of the electromagnetic valve 1 is connected to the ground via an N-channel MOSFET 13 as a third switching element. A diode 13a is connected to the MOSFET 13 in antiparallel. The output terminal C of the booster circuit 3 is connected to the negative terminal B of the solenoid valve 1 through an N-channel MOSFET 14 as a fourth switching element. The diode 14a is connected to the MOSFET 14 in antiparallel. The diodes 8a, 9a, 11a, 13a, and 14a may be incorporated in the MOSFETs 8, 9, 11, 13, and 14 or may be provided externally.

  The control circuit 20 performs drive control of the booster circuit 3 and energization control to the solenoid valve 1. The control circuit 20 gives a drive signal Sa to the MOSFET 5 of the booster circuit 3. The control circuit 20 applies drive signals S1, S2, S3, S4, and S5 to the MOSFETs 8, 9, 11, 13, and 14, respectively, thereby energizing the coil 1a of the electromagnetic valve 1 as described later. While operating the valve 1, the residual magnetic flux of the electromagnetic valve 1 is demagnetized.

Next, the operation of the above configuration will be described with reference to FIGS.
First, the operation of energizing the solenoid valve 1 in the positive direction by the control circuit 20 will be briefly described. The control circuit 20 gives a drive signal Sa to the MOSFET 5 of the booster circuit 3 to perform a boost operation. Although not shown, the drive signal Sa is output from the control circuit 20 so as to have a predetermined voltage.

  When the MOSFET 5 is turned on, the booster coil 4 is energized. When the MOSFET 5 is turned off, the capacitor 7 is charged with a voltage higher than the DC power supply VB via the diode 6 by the electromotive force of the booster coil 4. By repeating this, the boosted voltage can be supplied to the capacitor 7.

  In the state where the boosting power source is generated by the booster circuit 3 as described above, the control circuit 20 energizes the solenoid valve 1 to control driving. As shown in FIGS. 2B and 2C, the control circuit 20 first outputs drive signals S3 and S1 to turn on the MOSFETs 9 and 8 at time t1. As a result, an energization path from the output terminal C of the booster circuit 3 to the ground via the MOSFET 8, the coil 1a, the MOSFET 9, and the resistor 10 is formed. The voltage boosted from the booster circuit 3 is applied to the coil 1a from the positive terminal A, and as shown in FIG. 2A, the solenoid valve current Ia that rapidly rises from the time t1 is energized in the positive direction. Is opened.

  The control circuit 20 holds the drive signal S3 in a high level state until the energization period to the coil 1a ends. Further, the control circuit 20 switches the drive signal S1 to the low level at time t2 when a predetermined time has elapsed from time t1. Thereby, since MOSFET8 changes to an OFF state, solenoid valve current Ia falls rapidly from a peak value.

  Thereafter, the control circuit 20 outputs the drive signal S2 at time t3 when the electromagnetic valve current Ia is at a predetermined level, and turns on the MOSFET 11 for a predetermined period. As a result, the coil 1a is energized in the positive direction from the DC power source VB via the diode 12, and as shown in FIG. 2A, the electromagnetic valve current Ia corresponding to the DC power source VB is energized for a predetermined period from time t3. . When the predetermined period elapses, the control circuit 20 switches the drive signal S2 to a low level and turns off the MOSFET 11 for a predetermined period. Thereby, the solenoid valve current Ia also decreases.

  The control circuit 20 repeats the above energization control by the DC power supply VB a predetermined number of times to maintain the energization state of the solenoid valve 1, and thereby the solenoid valve 1 is kept open. Then, at time t5, the control circuit 20 switches the drive signal S3 to the low level together with the drive signal S2. As a result, the MOSFET 11 and the MOSFET 9 are both turned off, the electromagnetic valve current Ia decreases with time, and the electromagnetic valve 1 is closed.

  In this manner, the solenoid valve 1 is driven to open when the solenoid valve current Ia is applied to the coil 1a of the solenoid valve 1 during the period from time t1 to time t5, so that a predetermined operation is performed. When the solenoid valve current Ia becomes zero and the solenoid valve 1 is closed at time t6, the control circuit 20 subsequently performs a demagnetizing operation.

  The control circuit 20 energizes the coil 1a of the solenoid valve 1 in the reverse direction in the degaussing operation. In this case, the control circuit 20 outputs the drive signal S4 and the drive signal S5 for a predetermined time Ton. Thereby, the MOSFET 13 and the MOSFET 14 are turned on. As a result, an energization path from the output terminal C of the booster circuit 3 to the MOSFET 14, the coil 1 a, and the MOSFET 13 to the ground is formed as indicated by broken-line arrows x 1 to x 8 in FIG. As a result, the coil 1a of the electromagnetic valve 1 is energized in the reverse direction from the booster circuit 3 from the negative terminal B to the positive terminal A.

  At this time, the time Ton for conducting the reverse energization is set in advance so that the residual magnetic flux becomes zero when the solenoid valve current Ia is energized in the reverse direction to the coil 1a of the solenoid valve 1. As a result, demagnetization is performed so that the residual magnetic flux of the coil 1a becomes zero in a short period of time Ton. Therefore, even when the coil 1a is energized in the forward direction again after the time Ton has elapsed, the energization control can be performed in a state where there is no residual magnetic flux in the solenoid valve 1, and the drive control can be accurately performed according to the solenoid valve current Ia. become able to.

  Next, with reference to FIG. 4, the demagnetizing operation of the coil 1a due to the reverse energization will be described. In addition, the setting of the energization time Ton of the solenoid valve current Ia will also be described. FIG. 4A shows the solenoid valve current Ia shown in FIG. FIG. 4B shows a change in the electromagnetic valve flux Φ of the electromagnetic valve 1 at this time.

  As shown in FIG. 4 (a), when the solenoid valve current Ia flows from the booster circuit 3 to the coil 1a of the solenoid valve 1, the solenoid valve magnetic flux Φ also increases abruptly because the current rises rapidly at the beginning of energization. To reach a predetermined level. Thereafter, during a period in which power is directly supplied from the DC power source VB at a predetermined interval, the electromagnetic valve current Ia is maintained before and after a certain level, so that the electromagnetic valve magnetic flux Φ is also maintained at a predetermined level while following the electromagnetic valve current Ia. The And in the period when the solenoid valve current Ia decreases to zero, the solenoid valve magnetic flux Φ also gradually decreases, but by passing the solenoid valve current Ia in the reverse direction at time t6, the solenoid valve magnetic flux Φ decreases rapidly, It is possible to demagnetize to almost zero state in a short time until time t7.

  In this case, as shown by the broken line in FIG. 4A, in the conventional method in which no reverse current flows, as shown by the broken line in FIG. 4B, the residual magnetic flux is slowly applied until time t8. Degauss. As illustrated, in this embodiment, demagnetization is completed in a period T1 from time t6 to t7, whereas in the conventional system, demagnetization is completed in a period T2 from time t6 to t8. For this reason, the timing for energizing the solenoid valve 1 in the forward direction cannot be made earlier than the time t9, and if energization in the forward direction is performed before the natural demagnetization period T2 elapses, the solenoid valve current Ia is It cannot be accurately controlled, and the operation of the solenoid valve 1 cannot be accurately controlled.

  In this respect, since the solenoid valve 1 can be demagnetized in a short period of time T1 by carrying out the reverse direction energization of the present embodiment, the solenoid valve 1 corresponds to the solenoid valve current Ia even at a short time interval. Drive control can be performed accurately.

  In this embodiment, in order to demagnetize the residual magnetic flux of the solenoid valve 1 in this way, control is performed by energizing the reverse energization current for the period Ton. If this energization period Ton is short, the residual magnetic flux cannot be completely demagnetized. Conversely, if it is long, a residual magnetic flux in the reverse direction is generated. In this embodiment, the period Ton is set by measuring in advance the time during which the residual magnetic flux can be completely demagnetized by reverse energization.

  According to the first embodiment as described above, the MOSFETs 13 and 14 are provided to form an energization path so that the booster circuit 3 can perform reverse energization after the forward energization of the coil 1a of the solenoid valve 1. I was able to do that. Thereby, the control circuit 20 can demagnetize the residual magnetic flux of the solenoid valve 1 in a short time by performing the reverse direction energization for a predetermined time Ton after the forward direction energization. As a result, when the energization control of the solenoid valve 1 is repeatedly performed, the solenoid valve 1 can be controlled with high accuracy in a short period of time.

(Second Embodiment)
FIG. 5 and FIG. 6 show the second embodiment, and the following description will be focused on differences from the first embodiment. In this embodiment, the solenoid valve drive device 20 is provided with a booster circuit 21 that replaces the booster circuit 3. In this embodiment, the control circuit 20 controls the coil 1a of the solenoid valve 1 in the reverse direction with the current value instead of the energization time Ton.

  As shown in FIG. 5, in the booster circuit 21, the capacitor 7 has one end connected to the output terminal C and the other end connected to the ground via the current detection resistor 22. The voltage at both terminals of the current detection resistor 22 is detected by the current detection circuit 23 to detect the discharge current from the capacitor 7. The current detection circuit 23 outputs the detected current value data to the control circuit 20.

Next, the operation of the above configuration will be described for parts different from the first embodiment.
In this embodiment, in reverse energization for demagnetizing the residual magnetic flux after energization in the forward direction to the solenoid valve 1, the energization time Ton is not set, but the level of the solenoid valve current Ia is detected and turned off. I have to.

  Specifically, as shown in FIG. 6, the control circuit 20 outputs high-level drive signals S4 and S5 at time t6 to turn on the MOSFETs 13 and 14, and then the electromagnetic valve 1 is operated in the reverse direction. The valve current Ia is detected by the current detection circuit 23 as a current flowing through the current detection resistor 22 in the direction of the arrow x0 in the figure.

At time t7a when the electromagnetic valve current Ia reaches the threshold current Ith, the control circuit 20 inverts the drive signals S4 and S5 to a low level to turn off the MOSFETs 13 and 14. At this time, the threshold current Ith is set to a value obtained by measurement or the like as a current value that can demagnetize the residual magnetic flux of the solenoid valve 1 in advance. As a result, the residual magnetic flux of the electromagnetic valve 1 can be demagnetized in a short period.
Therefore, also by such 2nd Embodiment, the effect similar to 1st Embodiment can be acquired.

(Third embodiment)
FIG. 7 shows the third embodiment. Hereinafter, parts different from the first embodiment will be described. In this embodiment, the solenoid valve driving device 30 has a configuration in which the drain of the reverse-direction energization MOSFET 14 is connected to the DC power supply VB.

  With the above configuration, when the control circuit 20 outputs the high level drive signals S4 and S5 to turn on the MOSFETs 13 and 14 at time t6, as indicated by broken line arrows y1 to y7 in the figure, the DC power source VB to the MOSFET 14, A solenoid valve current Ia in the reverse direction of the solenoid valve 1 flows through the coil 1a and the MOSFET 13.

  The electromagnetic valve current Ia is controlled by the control circuit 20 so as to flow for a predetermined time. At this time, the energizing time of the reverse solenoid valve current Ia flowing through the coil 1a of the solenoid valve 1 is set in advance so that the residual magnetic flux can be demagnetized by measurement or the like.

  Therefore, according to the third embodiment, the same effect as that of the first embodiment can be obtained. Further, since the reverse solenoid valve current Ia is supplied from the DC power supply VB, the capacitor of the booster circuit 3 can be obtained. By not using the charge charge 7, it is possible to suppress the fluctuation of the charge voltage during the demagnetization period, and to affect the next time the solenoid valve current Ia in the forward direction is energized from the booster circuit 3. And can be controlled with high accuracy.

  Note that the configuration used in the third embodiment can also be applied to the control for detecting the electromagnetic valve current Ia in the reverse direction and changing the drive signals S4 and S5 to the low level as in the second embodiment.

(Other embodiments)
In addition, this invention is not limited only to embodiment mentioned above, In the range which does not deviate from the summary, it is applicable to various embodiment, For example, it can deform | transform or expand as follows.

  In each of the above embodiments, the MOSFETs 13 and 14 are used as the third and fourth switching elements, but other switching elements such as IGBTs or bipolar transistors can also be used.

  In each of the above embodiments, the configuration example in which the MOSFET 8 is provided as the first switching element so as to supply the boosted voltage from the booster circuit 3 or 21 in the initial stage of energization of the coil 1a of the solenoid valve 1 is shown. A configuration in which power is directly supplied from the DC power supply VB via the MOSFET 11 in the initial stage of energization without using the circuits 3 and 21 may be employed.

In each of the above embodiments, the case where an in-vehicle battery is used as the DC power source VB is illustrated, but the DC power source is not limited to the in-vehicle battery.
Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments and structures. The present disclosure includes various modifications and modifications within the equivalent range. In addition, various combinations and forms, as well as other combinations and forms including only one element, more or less, are within the scope and spirit of the present disclosure.

  In the drawings, 1 is a solenoid valve, 1a is a coil, 2, 20, 30 are solenoid valve driving devices, 3, 21 is a booster circuit, 4 is a booster coil, 8 is a MOSFET (first switching element), and 9 is a MOSFET (first switch). 2 switching elements), 11 MOSFET (first switching element), 13 MOSFET (third switching element), 14 MOSFET (fourth switching element), 20 control circuit, 22 current detection resistor, 23 current detection Circuit.

Claims (6)

A control circuit (20) that controls driving by energizing the positive electrode terminal and the negative electrode terminal of the solenoid valve (1) in a positive direction from a DC power source via the first switching element (11) and the second switching element (9), respectively. And a solenoid valve driving device comprising:
A third switching element (13) having a diode (13a) connected in reverse parallel and connecting the positive terminal of the solenoid valve to the negative side;
A fourth switching element (14) having a diode (14a) connected in reverse parallel and connecting the negative terminal of the solenoid valve to the positive side;
The third switching element and the fourth switching element are electromagnetic valve driving devices that are driven by the control circuit when the first and second switching elements are off.   The control circuit drives the first and second switching elements to drive the electromagnetic valve, and then drives the third and fourth switching elements when the current to the electromagnetic valve disappears to drive the electromagnetic valve. The electromagnetic valve driving device according to claim 1, wherein the valve is energized in the reverse direction.   The electromagnetic valve driving device according to claim 2, wherein the control circuit demagnetizes the electromagnetic valve by driving the third and fourth switching elements for a predetermined time.   The electromagnetic valve driving device according to claim 2, wherein the control circuit demagnetizes the electromagnetic valve by driving the third and fourth switching elements until a predetermined current is reached. A booster circuit (3) for boosting the DC power supply in order to drive the solenoid valve at a voltage higher than the voltage of the DC power supply;
5. The electromagnetic valve driving device according to claim 1, wherein the fourth switching element is provided so as to apply a voltage of the booster circuit to energize the electromagnetic valve in a reverse direction. 6.   The solenoid valve driving device according to any one of claims 1 to 5, wherein the fourth switching element is provided so as to apply a voltage of the DC power source to energize the solenoid valve in a reverse direction.

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