JPH06132116A - Electromagnet coil driving apparatus - Google Patents

Abstract

PURPOSE:To realize high speed operation of rotor and ease rebound thereof by adequately attenuating a coil current. CONSTITUTION:While a switch 2 is closed, a pulse signal generating circuit 5 turns off a switching element 4 to keep almost constant a current flowing into a coil 3 by controlling it with a chopper. While the switching element 4 is in the off state, the curernt flowing into the coil 3 is regenerated by a first regenerating circuit consisting of a transistor 7 and a diode 6. When the switch 2 is opened to remove a power supply voltage, the pulse signal generating circuit 5 stops turning off the switching element 4. Moreover, the transistors 13, 7 turn off setting the first regeneration circuit to the non-conductive state. Cut-off condition of the first regenerating circuit attenuates the coil current. Here, the coil current attenuates more slowly than that in the conventional surge absorbing element by properly selecting a zener voltage Vz of a zener diode 8 to a small value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnet coil drive device using an electronic circuit.

[0002]

2. Description of the Related Art For example, as a coil driving device for an electromagnet of an electromagnetic contactor, a large current is applied when a movable iron core is attracted,
After the adsorption, a method is often used in which the chopper is controlled by a pulse signal and only the power consumption necessary for the adsorption holding is supplied to the coil. FIG. 9 is an example of such a circuit. While the switch 2 is closed, the switching element 4 is turned on / off by an appropriate pulse generated from the pulse signal generation circuit 5,
The current ic flowing through the coil 3 is chopper-controlled to maintain a substantially constant value I ₀ . While the switching element 4 is off, the current ic flowing in the coil 3 is regenerated through the diode 6. Incidentally, 1 is a DC power supply.

However, in the circuit of FIG. 9, since the regenerative circuit is only the diode 6, the current ic of the coil 3 continues to flow through the diode 6 when the switch 2 is opened to remove the power supply voltage (see FIG. 2). (Refer to (b)), the disadvantage that the contact release time is long, and the speed of the mover when moving from the position of the mover when energized to the position of the mover when de-energized is slow, and a large DC current load is applied. There was a problem that the arc generated at the contact at that time was difficult to cut.

The dic / dt at this time is given by the following equation by the forward voltage drop Vf of the diode 6 and the inductance L of the coil 3. dic / dt =-| Vf / L | ... As a means for solving these drawbacks, for example, there is a circuit system as shown in FIG. In this method, a transistor 7 is connected in series with a diode 6 to form a regenerative circuit. When the switch 2 is opened to remove the power supply voltage,
The transistor 7 is turned off, and the regenerative circuit is turned off.

Therefore, the current ic flows through the surge absorbing element 8 and becomes zero in an extremely short time as shown in FIG. 2 (b). The dic / dt at this time is the surge absorption element 8
Surge limit voltage Vz and the inductance L of the coil 3
Is given by dic / dt≈− | Vz / L | ... The energy of the surge generated by the interruption of the current ic is absorbed by the surge absorbing element 8.

Further, the transistor 7 is turned on while the switch 2 is closed by the resistors 9 and 10, and the transistor 7 is turned off when the switch 2 is opened. According to this method, the contact release time can be shortened and the speed of the mover can be increased.

[0007]

As described above, with the circuit system shown in FIG. 10, it is possible to shorten the contact release time without changing the spring force, and to increase the speed of the mover at the time of opening. became. However, by using the surge absorbing element 8 having a large surge limiting voltage Vz, as shown in FIG.
As shown in (b), the coil current i
When c is cut off, the mover moves quickly, but the spring is pushed in too much, so the mover rebounds greatly due to the large repulsive force of the spring, and the mover's position when energized and when it is de-energized If the child positions are close,
There is a problem that the separated contacts may come back again due to the removal of the power supply voltage.

The present invention has been provided in view of the above points, and a coil driving device for an electromagnet for the purpose of appropriately attenuating a coil current to speed up the mover and reduce rebound. Is provided.

[0009]

According to the present invention, a coil for exciting an electromagnet, a means for supplying a power supply voltage to the coil by turning on / off a switching element, and a coil connected in parallel to the coil for switching when power is supplied. In the coil drive device of the electromagnet, which has a regenerative circuit that becomes conductive when the element is off, regenerates a current in the coil when the element is off, and then immediately becomes non-conductive after the power supply voltage is removed. A Zener diode that appropriately attenuates the current flowing through the coil after removing the power supply voltage is provided in parallel with the regenerative circuit.

Further, according to a second aspect of the present invention, there is provided a second regenerative circuit which is connected in parallel with the coil and becomes conductive after the power supply voltage is removed to appropriately attenuate the current flowing through the coil. .

[0011]

According to the present invention, by using a Zener diode having an appropriate Zener voltage, the coil current can be appropriately attenuated, and the position of the mover when the power supply voltage is applied at high speed with less rebound. Can be moved to the position where the power supply voltage was removed from.

Further, according to a second aspect of the present invention, there is provided a second regenerative circuit which is connected in parallel with the coil and becomes conductive after the power supply voltage is removed to appropriately attenuate the current flowing through the coil. Therefore, when the coil current is attenuated, first, the first regenerative circuit is cut off, and the regenerative current path is switched from the side having a large attenuation rate by the second regenerative circuit having a small attenuation rate, so that the number of movers is high and small. It is possible to move from the position where the power supply voltage is applied by rebound to the position where the power supply voltage is removed.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a specific circuit diagram. 1 to 8 are the same as those in FIGS. 9 and 10, and a Zener diode 8 is used as a surge absorbing element. Although 9 to 12 are resistors and 13 is a transistor, resistors 9 to 12 and transistor 1
3 makes the transistor 7 conductive while the switch 2 is closed, and makes the transistor 7 open when the switch 2 is opened.
Is made non-conductive, the resistances 9 and 1 of FIG.
Works the same as 0.

Next, the operation of the circuit configuration shown in FIG. 1 will be described with reference to FIG.
A description will be given with reference to (a) and FIG. Switch 2
While is closed, the pulse signal generation circuit 5 generates a large pulse for adsorbing and holding the movable iron core, and then turns on and off the switching element 4 to control the current ic flowing through the coil 3 by a chopper control. And maintain a substantially constant value I ₀ .

While the switching element 4 is off,
The current ic flowing through the coil 3 is regenerated through the first regeneration circuit including the transistor 7 and the diode 6. Time t
_When the switch 2 is opened to ₀ and the power supply voltage is removed, the pulse signal generation circuit 5 is stopped and the switching element 4 is turned off. Further, the transistor 13 is turned off, and thus the transistor 7 is also turned off, and the first regenerative circuit is turned off. Due to the interruption of the first regenerative circuit, the coil current ic is attenuated as given by the equation.

Here, by appropriately selecting the Zener voltage Vz of the Zener diode 8, the coil current ic is attenuated more slowly than in the case of as shown in FIG. 2 (b). FIG. 3 shows the speed and rebound of the mover when the zener voltage of the zener diode 8 is changed in an electromagnet device having a mover stroke of 1 mm. As shown in FIG. 3, it can be seen that by appropriately selecting the Zener voltage, the rebound is reduced while maintaining the high speed.

Although the present invention has been described by taking the electromagnetic contactor as an example, the present invention can be applied not only to the electromagnetic contactor but also to an electromagnet device in general in which the mover is governed by the electromagnetic force and the spring force. (Embodiment 2) Embodiment 2 is shown in FIG. This embodiment is shown in FIG.
In addition to the first regenerative circuit and the surge absorbing element that operate similarly to the circuit system shown in 0, a second regenerative circuit that becomes conductive with appropriate timing or a change in resistance value after the first regenerative circuit is cut off. Is provided.

In this embodiment, as shown in FIG.
The transistor 14 and the diode 15 form a second regenerative circuit. Reference numerals 16 and 19 are resistors, 17 is a capacitor, and 18 is a diode. The resistors 16, 19 and the capacitor 17 and the diode 18 constitute a timing circuit for turning on the MOS transistor 14.

Next, the operation of the circuit configuration of FIG. 4 will be described with reference to FIG.
This will be described with reference to (a) and FIG. 5 (b). Note that FIG.
Shows a waveform diagram similar to that of FIG. While the switch 2 is closed, the pulse signal generation circuit 5 generates a pulse for attracting and holding a large pulse for attracting the movable iron core to turn on / off the switching element 4, and the current ic flowing through the coil 3 is choppered. It is controlled to maintain an almost constant value I ₀ .

While the switching element 4 is off,
The current ic flowing through the coil 3 is regenerated through the first regeneration circuit including the transistor 7 and the diode 6. Time t
_When the switch 2 is opened to ₀ and the power supply voltage is removed, the pulse signal generation circuit 5 is stopped and the switching element 4 is turned off. Further, the transistor 13 is turned off, and thus the transistor 7 is also turned off, and the first regenerative circuit is turned off. Due to the interruption of the first regenerative circuit, the coil current ic begins to decay as given by the equation.

On the other hand, by shutting off the first regenerative circuit, a surge having a voltage substantially equal to the surge limiting voltage Vz of the surge absorbing element 8 is applied to both ends of the coil 3, so that the capacitor 17 is charged by this surge. The capacitor 17 has no charge accumulated until a surge voltage is applied at time t ₀ by the diode 18 and the resistor 19, and the charging time constant is determined by the product of the capacitance value of the capacitor 17 and the resistance value of the resistor 18.

Then, the voltage of the capacitor 17 becomes MOS.
At time t ₁ when the threshold of the transistor 14 is reached, the MOS
The transistor 14 becomes conductive, and thereafter, the current ic comes to be regenerated through the second regeneration circuit. Therefore,
The current ic will decay slowly as approximately given by the equation.

FIG. 6 shows the speed and rebound of the mover when the resistance value of the resistor 16 is changed while the capacitance value of the capacitor 17 is constant in an electromagnet device having a stroke of the mover of 1 mm. The resistance of the resistor 16 as appropriate
It is understood that by selecting the capacitance value of the capacitor 17, rebound can be reduced while maintaining high speed. As described above, in the present embodiment, when the coil current is attenuated, the first regenerative circuit is first shut off, and the surge absorption element having the large attenuation rate is changed to the appropriate timing or resistance value for the second regenerative circuit having the small attenuation rate. In order to switch the regenerative current path according to the change of, the mover can be moved at a high speed and with a small rebound from the position where the power supply voltage is applied to the position where the power supply voltage is removed.

(Embodiments 3 and 4) FIGS. 7 and 8 show Embodiments 3 and 4, and in FIGS. 7 and 8, the same reference numerals as in FIG. 4 function in principle the same as in the above embodiments. In the embodiment of FIG. 7, an AC power supply 21 is used, 22 is a diode bridge, and 23 is a smoothing capacitor. As described above, the present invention is not limited to the type of power source.

In the second regenerative circuit, a thyristor is used as the switching element 14. In the embodiment of FIG. 8, a transistor is used as the switching element 14, and the transistor 14 serves as a switching element depending on the resistance values of the resistors 16, 19, and 20 and the capacitance value of the capacitor 17, and the resistance of the second regenerative circuit is used. It also serves as an element that variably reduces the value.

Besides, the switching element 14 may be a photocoupler, an SSR, a triac, an IGBT or the like. As described above, the present invention is not limited to the type of the element 14. In addition, in the embodiment of FIG.
It is driven by using the UT 24 and the resistors 25 to 27. As described above, in the present invention, the means for driving the element 14 does not matter.

As described above, the present invention has been described by taking the electromagnetic contactor as an example. However, the present invention is not limited to the electromagnetic contactor and is applicable to general electromagnet devices in which a mover is governed by electromagnetic force and spring force. It is possible.

[0028]

As described above, according to the present invention, a coil for exciting an electromagnet, a means for supplying a power supply voltage to the coil by turning on / off a switching element, and a coil connected in parallel to the coil for switching when power is supplied. In the coil drive device of the electromagnet, which has a regenerative circuit that becomes conductive when the element is off, regenerates a current in the coil when the element is off, and then immediately becomes non-conductive after the power supply voltage is removed. Since a Zener diode that appropriately attenuates the current that flows in the coil after removing the power supply voltage is provided in parallel with the regenerative circuit, use a Zener diode with an appropriate Zener voltage to make the coil current appropriate. The power supply voltage can be reduced from the position when the power supply voltage is applied to the mover at high speed and with little rebound. In which an effect that can be moved to a position at which were removed.

Further, according to the present invention, a second regenerative circuit is provided which is connected in parallel with the coil and becomes conductive after the power supply voltage is removed to appropriately attenuate the current flowing through the coil. Therefore, when the coil current is attenuated, first, the first regenerative circuit is cut off, and the regenerative current path is switched from the side having a large attenuation rate by the second regenerative circuit having a small attenuation rate, so that the number of movers is high and small. It is possible to move from the position where the power supply voltage is applied by rebound to the position where the power supply voltage is removed.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of the above.

FIG. 3 is a characteristic diagram showing the relationship between the speed and rebound of the mover when the Zener voltage of the Zener diode is changed.

FIG. 4 is a circuit diagram of a second embodiment of the above.

FIG. 5 is an operation explanatory diagram of the above.

FIG. 6 is a characteristic diagram showing the relationship between the speed and rebound of the mover when the resistance value of the resistor 16 is varied.

FIG. 7 is a circuit diagram of a third embodiment of the above.

FIG. 8 is a circuit diagram of Embodiment 4 of the above.

FIG. 9 is a circuit diagram of a conventional example.

FIG. 10 is a circuit diagram of another conventional example.

[Explanation of symbols]

 1 DC power supply 2 Switch 3 Coil 4 Switching element 5 Pulse signal generation circuit 6 Diode 7 Transistor 8 Zener diode

[Procedure amendment]

[Submission date] January 18, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

On the other hand, by shutting off the first regenerative circuit, a surge having a voltage substantially equal to the surge limiting voltage Vz of the surge absorbing element 8 is applied to both ends of the coil 3, so that the capacitor 17 is charged by this surge. Charge is not accumulated in the capacitor 17 until a surge voltage is applied at time t ₀ by the diode 18 and the resistor 19, and the charging time constant is determined by the product of the capacitance value of the capacitor 17 and the resistance value of the resistor 16 .

Claims (2)

[Claims] 1. A coil for exciting an electromagnet, a means for supplying a power supply voltage to the coil by turning on / off a switching element, and a coil connected in parallel to the coil, which is in a conductive state when the switching element is off when power is supplied. In the coil drive device of the electromagnet, which has a regenerative circuit that instantly becomes non-conducting after the current is regenerated in the coil and the power supply voltage is removed, the coil is removed after the power supply voltage is removed by a predetermined Zener voltage. A coil drive device for an electromagnet, wherein a zener diode that appropriately attenuates a flowing current is provided in parallel with a regenerative circuit. 2. A second regenerative circuit which is connected in parallel with the coil and which is rendered conductive after the power supply voltage is removed and which appropriately attenuates the current flowing through the coil. Electromagnet coil drive.