JP2003515905A - Electromagnetic switchgear, method of controlling input speed and drive circuit - Google Patents

Abstract

(57) [Summary] The relationship between the amount of movement of the contact support (5) of the electromagnetic switchgear (1) and time is measured by the magnetic field sensor (10). For this purpose, a microprocessor (16) evaluates the output signal of the magnetic field sensor and determines the speed of the contact carrier or a part fixedly connected thereto. Based on this, the microprocessor controls the current in the coil (3) of the electromagnet device. As a result, the contact closing speed is not unnecessarily increased, chattering and noise during closing can be reduced, and the electrical and mechanical life of the appliance can be extended.

Description

Detailed Description of the Invention

The present invention relates to a method for controlling the closing speed of an electromagnetic switch according to the preamble of claim 1. Furthermore, the present invention provides an electromagnetic switching device according to the preamble of claim 12 and claim 14.
The present invention relates to a drive circuit for an electromagnetic switchgear according to the preceding sentence.

A conventional electromagnetic switching device having an electronic drive unit is controlled by a coil current with respect to its closing operation. The closing operation of this drive device has the following problems.・ Large contact chattering ・ Short electrical life ・ Large mechanical wear ・ Short mechanical life ・ Large switching noise

In the conventional drive device, the minimum coil current is supplied by current control regardless of the applied operating voltage. As a result, the drive was able to operate with minimal magnetic excitation, independent of the applied control voltage. In this way, the effect of the control supply voltage, which significantly reduces the closing speed with respect to the uncontrolled drive, is eliminated. However, in that case, the excitation of the coil did not match the speed of the contact carrier of the switching device, which resulted in an unnecessarily high closing speed of the contacts and the magnetic drive.

It is therefore an object of the present invention to provide a method and a device as described above, and a circuit related thereto, in which the closing speed of the contacts can be optimized by appropriate control of the coil current.

According to the invention, the method-related problem is solved by the method according to claim 1. Advantageous examples of this method are described in claims 2 to 11.

By using a magnetic field sensor that measures the position of the contact support, the velocity can be estimated from the relationship between the amount of movement of the contact support and time. This can be advantageously achieved by using a giant magnetoresistive element that produces a linear output signal in response to changes in the magnetic field. Along with this, the relationship between the movement amount and time can be obtained easily and inexpensively, and therefore speed control can be performed.

The problems relating to the device are achieved by the electromagnetic switching device according to the twelfth aspect. In this case, in order to measure the relationship between the amount of movement and time, it is preferable to use a magnetic field sensor that measures changes in the magnetic field obtained by the permanent magnet. This permanent magnet is then fixed to the anchor of the electromagnet device. The relationship between the measured amount of movement of the anchor and time corresponds to that of the contact support coupled to it and the movable contact fixed thereto.

[0008]   Further, the problem relating to the drive circuit of the electromagnetic switching device is solved by claim 14.

[0009]   Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an electromagnetic switchgear 1, for example, an electromagnetic contactor, in a simplified manner by limiting it to those parts which are important for the description of the present invention. The opening / closing device 1 includes an electromagnet device including a fixed yoke 2, a coil 3, and a movable anchor 4 fixedly coupled to a contact support 5. The contact carrier 5 comprises a movable contact 6 which opens and closes a current circuit in association with the fixed contact 7 when the electromagnet arrangement is activated. The switchgear 1 further includes a printed board 8 for driving control, that is, having a circuit for controlling the coil current of the exciting coil 3.

According to the invention, the switchgear 1 is equipped with means 9, 10 for detecting the relationship between the amount of movement of the contact carrier 5 or of the part fixedly connected to it, and time.

As this means, here, the permanent magnet 9 fixed to the anchor 4 and the magnetic field sensor 10 integrated in the circuit of the printed board 8, for example, a giant magnetoresistive effect element (GMR) are used.
(Also called). When the switching device 1 is actuated, the permanent magnet 9 moves with the contact carrier 5 and the anchor 4. A change in the magnetic field caused by this is caused by the magnetic field sensor 10.
Detected in. The magnetic field sensor, here GMR, produces a resistance R proportional to the amount of movement s of the permanent magnet 9. That is, this resistance R represents the position of the permanent magnet 9 or the contact support 5 and the anchor 4. In the sensor characteristic diagram of FIG. 2 measured by the magnetic field sensor 10, the resistance R
And the movement amount s are shown.

[0013]   FIG. 3 schematically shows the control circuit of the printed board 8 within the range necessary for understanding the present invention.

This circuit includes input terminals A1 and A2 for connecting a DC voltage (DC) or an AC voltage (AC), a rectifier 11 is connected to the input side, and an electromagnetic contactor coil 12 (from the output side). (Corresponding to 3 in FIG. 1), a voltage is supplied to the series circuit including the switching transistor 13 and the shunt resistor 14. As is known, a diode circuit forming a freewheel circuit is connected in parallel to the electromagnetic contactor coil 12. The current evaluation of the electromagnetic contactor coil 12 is carried out via the shunt resistor 14, for which the voltage applied to the shunt resistor 14 is an analog-to-digital converter 15 and the following micro-controller as an intelligent control unit. It is guided to the processor 16. Furthermore, the supply voltage applied to the microprocessor 16 via a shunt on the output side of the rectifier 11 is introduced for evaluation. Further, the microprocessor 1
A control voltage proportional to the resistance R of the magnetic field sensor 10 is introduced to the line 6. With respect to the above three input quantities, namely the coil current, the supply voltage and the voltage U corresponding to the position of the contact support 5 or the relationship between the travel distance and the time derived therefrom, the microprocessor 16 controls the opening and closing transistor via the amplifier 17. An open / close signal is given to 13.

Therefore, with the microprocessor 16 as an intelligent control unit,
By detecting the position of the contact support body 5, and thus the relationship between the amount of movement and time, during the closing process, the opening / closing device drive unit can be closed at the optimum speed. The actual speed of the drive is compared to the optimum reference value for the switchgear. According to the deviation, the coil current is adjusted to that, and the desired speed ideal value is realized. By adjusting the speed characteristic in accordance with the position of the switchgear, the speed is changed in accordance with the moving amount s, and thereby a contact closing speed and an electromagnet closing speed that are appropriately small are realized. Therefore, it is possible to close the contacts and the magnetic drive unit at the same time with a slight delay, even though the contacts and the magnetic drive unit are gently closed at the same time.

It is of course also conceivable to fix the permanent magnet 9 to another part which moves with it, for example to the contact carrier 5.

The automatic adjustment of the opening / closing device 1 is performed at a stage according to the flowchart of FIG. In that case,
The intelligent control unit 16 detects the static steady state of the contact carrier 5 after the first closing, which is carried out with a constant or uncontrolled current. Since this reference value of the position "make" is set or stored for all subsequent opening and closing movements, cumbersome adjustment and adjustment movements can be omitted. In the subsequent opening / closing operation according to the flowchart of FIG. 5,
The speed control according to the movement amount of the contact support is performed with reference to the relationship between the movement amount and time or the characteristic with respect to the speed, which is present in this device. The deceleration is performed immediately before closing the contacts and the magnetic drive unit. Therefore, the mechanical and electrical life can be significantly improved. Furthermore,
The speed profile can be optimized for specific operating conditions.

[0018]   The automatic adjustment of the opening / closing device 1 can be executed by the factory or the customer side in the following stages. 1. Give a closing command (block 21) 2. Closing the contacts of the switchgear (block 22) 3. The stable state of the contact device is recorded by the magnetic field sensor (block 23). 4. Store stable state as reference value for loading position (block 24) 5. Cancel the closing command, that is, open the contact (block 25)

Other opening and closing operations for normal operation are performed according to the flow chart of FIG. This involves the following steps. That is, if there is a close command, block 26 checks and block 27 checks if the control voltage is above the target value U _min . If not, block 28 issues a false notification. Otherwise, the opening and closing stroke is started in block 29, and then in block 30, the speed is controlled until the opening and closing device is closed with reference to the previously set characteristic curve. Then, in block 31, the holding current is controlled. In block 32, the closing command is monitored for liveness, so that the switchgear is activated or else it is opened in block 33.

[Brief description of drawings]

[Figure 1]   The principal part of an electromagnetic switch is shown.

[Fig. 2]   The sensor characteristic detected by a magnetic field sensor is shown.

[Figure 3]   The drive circuit of an electromagnetic switch is shown.

[Figure 4]   3 shows a flow chart of the automatic adjustment of the opening / closing device according to the invention.

[Figure 5]   The flowchart of the opening / closing operation at the time of normal operation is shown.

[Explanation of symbols]

1 electromagnetic switchgear 2 York 3 coils 4 anchor 5 contact support 6 movable contacts 7 fixed contacts 8 printed boards 9 Permanent magnet 10 Magnetic field sensor 11 Rectifier 12 Electromagnetic contactor coil 13 open / close transistor 14 shunt resistance 15 Analog-to-digital converter 16 microprocessors 17 Amplifier

─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Lunggardir, Diethard             Federal Republic of Germany Day-96135 Ste             Kuraurac am Amselweg 5 F-term (reference) 5G057 AA07 AA08 KK01 KK27 RR10

Claims (14)

[Claims] 1. An electromagnet device comprising an anchor (4) fixedly coupled to a contact carrier (5) comprising a movable contact (6), the movable contact (6) and a fixed contact (7) opposite thereto.
) And an electromagnetic switchgear (1) configured to open and close a current circuit,
Particularly, in the method of controlling the closing speed of the electromagnetic contactor, the relationship between the movement amount of the contact support body (5) or a portion fixedly coupled to the contact support body (5) and time is measured at the time of opening the opening / closing device (1),
A method for controlling the closing speed of an electromagnetic switching device, characterized in that the current of the coil (3) of the electromagnet device is controlled based on this. 2. A contact support (5) or at least one measured value of the relationship between the amount of movement of a portion fixedly connected to the contact support (5) and time is compared with a reference value, and the coil is determined according to the deviation between the measured value and the reference value. The method according to claim 1, wherein the current of (3) is controlled. 3. A method as claimed in claim 1, characterized in that the static stable state of the contact support (5) in the closed state or of the part fixedly connected thereto is determined and stored. 4. Method according to claim 1, characterized in that the relationship between the movement of the anchor (4) and time is measured. 5. The velocity of the anchor (4), the contact support (5) or a portion fixedly connected to the anchor (4) is determined from the relationship between the measured movement amount and time.
The method according to any one of 1 to 4. 6. The method according to claim 1, wherein the relationship between the amount of movement and the time is determined by a magnetic field sensor (10) which produces an output signal in response to changes in the magnetic field. 7. A processing unit (1) for controlling an output signal of a current of a coil (3).
Method according to one of claims 1 to 6, characterized in that it leads to processing in 6). 8. A magnetic field sensor as a giant magnetoresistive element (10) for detecting a magnetic field emitted from a permanent magnet (9) fixed to an anchor (4). The method according to one. 9. Method according to claim 1, characterized in that the velocity of the contact carrier (5) or of the part fixedly connected to it is determined from the measured value of the relationship between displacement and time. . 10. The method according to claim 9, wherein the speed control is performed by referring to the relationship between the movement amount and the time or a characteristic curve obtained for the speed. 11. The speed of the contacts (6, 7) is controlled by controlling the current of the coil (3).
) And decelerating just before closing of the magnetic drive, method according to one of claims 1 to 9. 12. A contact device having a fixed contact (7) and a movable contact (6), and a contact support (5) having a movable contact (6) and fixedly coupled to an anchor (4) of an electromagnet device. An electromagnetic switchgear comprising: a switchgear (1) comprising means (9, 10) for measuring a relationship between a movement amount of a contact support (5) or a portion fixedly coupled to the contact support (5) and time. 13. A switchgear (1) is provided with a giant magnetoresistive effect element (10) as a magnetic field sensor for measuring the relationship between the amount of movement and time, whereby a contact support (5) or The electromagnetic switching device according to claim 12, characterized in that the magnetic field generated by the permanent magnet (9) provided at the portion fixedly coupled thereto is evaluated. 14. A coil (12) which is connected in series with an opening / closing element (13) and serves as an electromagnet device for operating a contact device, and a processing unit (6) connected thereto for controlling the opening / closing element (13). 16) and the processing unit (16) is connected to the magnetic field sensor (10), the control of the switching element (13) being performed by the processing unit (16) in relation to the output signal of the magnetic field sensor (10). A circuit for driving an electromagnetic switching device, in particular an electromagnetic contactor.