JP4872476B2 - Capacitor discharge load test equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge load tester for a capacitor which dispenses with an exchange of components, can be used semipermanently, and whose maximum load voltage variation is small. <P>SOLUTION: The tester is equipped with a power source 13, a pair of measuring terminals 11 to be connected to the capacitor 10, a charging circuit section 12 for applying the voltage of the power source to the capacitor via the measuring terminals, and a discharge circuit section 20 which is connected in parallel to the charging circuit 12 via the measuring terminals, and causes discharge current to flow via the measuring terminals on the occasion of discharging the capacitor. The discharge circuit 20 is equipped with a pair of cables 22 whose one-end sides are connected to the measuring terminals respectively, a switching means 21 which is connected to the other end sides of the cables and short-circuits/interrupts the discharge circuit section, and an inductance adjustment section 24 for performing adjustment to a desired discharge frequency by changing the interval between the pair of cables. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

The present invention relates to a capacitor discharge load test apparatus, and more particularly to a capacitor discharge load test apparatus used in a high voltage discharge circuit.

2. Description of the Related Art Conventionally, in a discharge circuit such as an in-vehicle HID lamp circuit, there is known a method in which a voltage charged in a capacitor is discharged using a spark gap and a discharge lamp is turned on with the electromotive voltage (see Patent Document 1). . In order to screen capacitors used in such a discharge circuit, a load test by discharge is necessary, and it is common to perform a discharge test using a circuit close to a discharge circuit by a spark gap that is actually used. .

FIG. 1 shows an example of a discharge circuit with a general spark gap. This discharge circuit includes a power source 1, a current limiting resistor 2, a capacitor 3, a discharge element 4 having a spark gap, a transformer 5, and a discharge lamp 6. The voltage of the power source 1 is charged to the capacitor 3 via the current limiting resistor 2. When the charging voltage of the capacitor 3 becomes higher than the breakdown voltage of the spark gap, the discharging element 4 causes breakdown and current flows to the primary coil side of the transformer 5. The voltage on the primary coil side is boosted by the transformer 5, and a high voltage is generated on the secondary coil side. By applying a high voltage generated on the secondary coil side to the discharge lamp 6, the discharge lamp 6 starts to discharge and lights up.

FIG. 2 shows a voltage change when a capacitor is discharged in the discharge circuit using the spark gap. As shown in FIG. 2, the voltage of the capacitor attenuates and oscillates at a predetermined frequency from 0V to the high voltage position (about 1 kV in this case), and eventually converges to 0V.

However, when the load test of the capacitor 3 is performed using the discharge circuit as described above, the replacement cost of the discharge element 4 is generated due to the deterioration of the spark gap, and the spark gap has a large variation in the maximum load voltage with respect to the rated voltage. There is a possibility that an excessive voltage is applied to the capacitor 3 and the life of the capacitor 3 itself is shortened. Therefore, there is a need for a discharge load test apparatus that does not require replacement of parts, can be used semipermanently, and has little variation in maximum load voltage.
Japanese Patent Laid-Open No. 10-308292

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a discharge load test apparatus for a capacitor that does not require replacement of parts, can be used semipermanently, and has little variation in maximum load voltage.

In order to achieve the above object, the present invention provides a power supply, a pair of measurement terminals connected to the capacitor, a charging circuit unit for applying a voltage of the power supply to the capacitor via the measurement terminal, and the measurement terminal. In the discharge load testing device for a capacitor, comprising: a discharge circuit unit that is connected in parallel with the charging circuit unit via the discharge circuit unit and causes a discharge current when the capacitor is discharged to flow through the measurement terminal. The one end side is connected to the measurement terminal, a pair of cables connected to the other end side of the cable, the switching means for short-circuiting / cutting off the discharge circuit section, and the distance between the pair of cables is changed. And an inductance adjusting unit that can be adjusted to a desired discharge frequency.

First, a capacitor is charged with a voltage via a charging circuit unit. After being charged to a predetermined voltage, the switching means is turned on, and the discharge circuit is short-circuited to discharge the capacitor charging current. At this time, since the discharge circuit unit constitutes an LCR series resonance circuit, the discharge circuit unit can be discharged at a predetermined discharge frequency by adjusting the inductance of the discharge circuit unit. The discharge performance of the capacitor can be confirmed by making the discharge frequency substantially coincide with the discharge frequency of the capacitor by the discharge circuit using the spark gap shown in FIG. The discharge load test apparatus of the present invention is configured without using a spark gap utilizing the breakdown phenomenon, and does not use unstable parts such as a spark gap, so that variation in the maximum load voltage can be suppressed. And there is no risk of shortening the lifetime of the capacitor itself. In addition, since no consumables such as a spark gap are used, there is no need for replacement of parts, and it can be used semipermanently.

The inductance of the discharge circuit unit changes the space between the cables by changing the distance between the pair of cables (or wirings), thereby changing the inductance. The discharge frequency also changes in inverse proportion to the inductance. In general circuit design, there are various methods for adjusting the inductance. For example, there is a method using an inductor (coil). However, there is a problem with durability against high voltage, and the inductance cannot be adjusted freely. It is not a simple adjustment method embodied as In the present invention, since the inductance is adjusted by changing the distance between the cables, the adjustment is very simple, the durability against high voltage is high, and the adjustment can be performed freely.

According to a preferred embodiment, the switching means is an insulated gate bipolar transistor, and it is preferable that a switching circuit for controlling the base current of the transistor to turn on / off the transistor is further provided.
If an insulated gate bipolar transistor is used as a switching means, the variation in the maximum load voltage is small, the discharge load test level to the capacitor can be stabilized, the durability against repeated use is great, and the life as a discharge test circuit Is greatly extended. Furthermore, the charge / discharge switching can be easily performed by the drive circuit, and a predetermined number of load tests can be automatically performed.

According to a preferred embodiment, the inductance adjusting unit has a first cable holding unit that holds a pair of cables at a minute interval at one end, and a pair of cables at a wider interval than the first cable holding unit at the other end. A base having a second cable holding portion to hold, and a pair of slidably provided between the first cable holding portion and the second cable holding portion on the base, and a pair of one side portion facing the first cable holding portion The first adjustment unit that adjusts the distance between the cables to the same distance as the first cable holding part is provided, and the distance between the pair of cables is set to the same distance as the second cable holding part on the other side facing the second cable holding part. And a slide member having a second adjustment portion to be adjusted.
In this case, the area formed between the pair of cables can be continuously varied by sliding the slide member with respect to the base, so that the inductance can be adjusted with high accuracy. Further, when the slide member is moved, the distance between the one end side and the other end side of the cable can be kept constant, so that the inductance can be changed proportionally.

It is preferable to further include an insulation resistance measuring device for measuring the insulation resistance of the capacitor in the next stage of the discharge load testing device according to the present invention.
After the capacitor is repeatedly charged and discharged at a high voltage a predetermined number of times using the discharge load test apparatus, the capacitor is removed from the discharge load test apparatus and connected to the next-stage insulation resistance measurement apparatus. If a defect occurs in the capacitor in the discharge load test, a predetermined insulation resistance cannot be obtained in the insulation resistance measurement, so that the defective capacitor can be easily selected.

As described above, according to the present invention, a capacitor discharge load test can be performed without using a discharge circuit due to a spark gap, so that variations in the maximum load voltage can be suppressed and the lifetime of the capacitor itself is shortened. There is no need to replace parts because there is no fear and parts with little change with time can be used. Furthermore, since the inductance of the discharge circuit portion is adjusted by changing the distance between the pair of cables, the structure is extremely simple and the durability against high voltage is high, and the adjustment can be freely performed.

Hereinafter, preferred embodiments of the present invention will be described with reference to examples.

FIG. 3 is a circuit diagram of a capacitor discharge load testing apparatus according to the present invention. The capacitor 10 as the subject is, for example, a discharge capacitor for an HID lamp.

The discharge load test apparatus includes a pair of measurement terminals 11 and 11 connected to the capacitor 10, a charging circuit unit 12 that applies a high voltage to the capacitor 10 through the measurement terminal 11, and charging through the measurement terminal 11. A discharge circuit unit 20 that is connected in parallel to the circuit unit 12 and flows a discharge current when the capacitor 10 is discharged is provided. The charging circuit unit 12 includes, for example, a power supply 13 that generates a high voltage of 1 kV, a current limiting resistor 14, and an application relay 15, and is configured to be able to apply a high voltage to the capacitor 10.

The discharge circuit unit 20 includes an insulated gate bipolar transistor 21 that is an example of a switching unit, and a pair of cables (wirings) 22 that connect the collector terminal and the emitter terminal of the transistor 21 to the measurement terminals 11 and 11, respectively. Yes. A drive circuit 23 for turning on / off the transistor is connected to the base of the transistor 21. Although an example of an NPN transistor is shown in FIG. 3, it is needless to say that a PNP transistor may be used.

FIG. 4 shows an inductance adjusting unit 24 that can adjust the inductance of the discharge circuit unit 20. The inductance adjusting unit 24 includes a base 25 made of an insulating material such as a resin, a rail unit 26 provided integrally with the base 25, a slide plate 27 provided slidably along the rail unit 26, and a rail unit. 26 is provided with a cable holding plate (first cable holding portion) 28 fixed to one end side. The slide plate 27 and the cable holding plate 28 are formed of the same insulating material as the base 25. The cable 22 is disposed in the longitudinal direction along the upper surface of the rail portion 26. On both sides of the rail portion 26, two rows of screw holes 26a are formed at a constant pitch in the longitudinal direction.

A relay terminal block 29 is fixed to one end side of the base 25, and a pair of first terminals 29 a that connect one end side of the cable 22 and a pair of second terminals 29 b are connected to the relay terminal block 29. Is provided. Both terminals 29a and 29b are connected to each other. The capacitor 10 is connected to the second terminal 29b through the measurement terminal 11. The two cables 22 connected to the first terminal 29 a are held at a minute interval by a cable holding plate 28 fixed in the vicinity of the relay terminal block 29. Here, the two cables 22 are held in a bundled state, but any cable can be used as long as it can maintain a constant interval. Although not shown in FIG. 4, the charging circuit unit 12 is connected to the first terminal 29 a or the second terminal 29 b of the relay terminal block 29.

The transistor 21 is fixed to the other end side of the base 25, and the other end side of the cable 22 is connected to a pair of terminals 21 a of the transistor 21. The terminal 21a also serves as a second cable holding portion that holds the pair of cables 22 at a wider interval than the cable holding plate 28.

The slide plate 27 is slidably provided between the cable holding plate 28 and the transistor 21 along the rail portion 26. A first adjustment portion 27 a that adjusts the distance between the pair of cables 22 to the same distance as the cable holding plate (first cable holding portion) 28 is provided on one side of the slide plate 27 facing the cable holding plate 28. On the other side facing the transistor 21, a second adjustment unit 27b for adjusting the interval between the pair of cables 22 to the same interval as the terminal (second cable holding unit) 21a is provided. Between both the adjustment parts 27a and 27b, the gradual change part 27c from which a space | interval changes gradually is provided. The slide plate 27 and the cable holding plate 28 are fixed to one of the screw holes 26 a of the rail portion 26 by a fixing screw 30. The method of fixing the slide plate 27 and the cable holding plate 28 to the base 25 is not limited to screwing, and a fixing pin, an adhesive, or the like may be used. In addition, since the movement with respect to the rail part 26 is controlled because the slide board 27 hold | maintains the cable 22, even if it does not have a special fixing means, it is also possible to stop the movement of the slide board 27. FIG.

4A shows a state in which the slide plate 27 is closest to the transistor 21, FIG. 4B shows a state in which the slide plate 27 is at an intermediate position between the transistor 21 and the cable holding plate 28, and FIG. Is a state in which the slide plate 27 is closest to the cable holding plate 28. By moving the slide plate 27, the distance between the pair of cables 22 changes, and the area of the space sandwiched between the two cables 22 (shown by hatching in FIG. 4) changes. The cable 22 is preferably a flexible wiring, and here, for example, a single core electric wire coated with silicon resin is used. As a result, the inductance of the discharge circuit unit 20 changes. The inductance shown in FIG. 4A is the smallest. In particular, when the slide plate 27 is moved, the cable 22 in the area indicated by hatching is in a parallel state, that is, the distance D between the cables 22 is kept constant, so that the inductance can be changed proportionally.

FIG. 5 shows an equivalent circuit of the discharge circuit unit 20.
The discharge circuit unit 20 including the capacitor 10, the cable 22, and the transistor 21 forms an LCR series resonance circuit as shown in FIG. Therefore, the discharge frequency f is given by the following equation.

よって、インダクタンスＬｓを調整することにより、放電回路部２０の放電周波数を調整することができる。

Therefore, the discharge frequency of the discharge circuit unit 20 can be adjusted by adjusting the inductance Ls.

なお、ａは導体半径〔ｍ〕、Ｄは導体間隔〔ｍ〕、μ₀ は真空の透磁率〔Ｈ／ｍ〕、μ_s は導体材質による比透磁率〔Ｈ／ｍ〕である。 Assuming that the current flowing through the discharge circuit unit 20 is direct current and the conductors are all cylindrical, the inductance L of the reciprocating circuit by the parallel cylindrical conductors 22 as shown in FIG.

Here, a is the conductor radius [m], D is the conductor spacing [m], μ ₀ is the vacuum permeability [H / m], and μ _s is the relative permeability [H / m] depending on the conductor material.

Since the equation (2) is an inductance per unit meter, assuming that the total length of the conductor is S, the inductance tends to increase if this length is increased. However, S cannot be expanded or contracted unless the conductor itself is an elastic body. In this embodiment, the distance D between the conductors is reduced to the shortest D = 2a.
log [(2a-a) / a] = log1 = 0
Thus, the value of log in equation (2) can be ignored. That is, when the D dimension is minimized by bundling the conductors even though the S dimension is constant, it is equivalent to the absence of the conductor, and as a result, the length of the conductor is changed without bundling. Be the same. The inductance L is proportional to the conductor length of the cable 22 remaining without being bundled. It is necessary that the distance D between the conductor portions remaining without being bundled is constant.

In the discharge load test apparatus shown in FIG. 3, before starting the discharge load test, the capacitor 10 serving as a reference is first connected to the measurement terminal 11, and a measuring instrument (such as an oscilloscope) is connected in parallel with the transistor 21. The discharge waveform when 10 is discharged is measured. The position of the slide plate 27 is adjusted and the inductance is adjusted so that the discharge waveform becomes a waveform (discharge frequency) similar to the discharge waveform due to the spark gap shown in FIG. After the adjustment of the inductance is completed, the measuring instrument is removed in the actual discharge load test. During the discharge load test to be described later, a measuring device may be connected periodically to measure the discharge frequency.

After performing the preliminary adjustment as described above, the capacitor 10 as the subject is connected to the measurement terminal 11 and a discharge load test is performed. The discharge load test is performed by a method as shown in FIG. First, the measurement terminal 11 is brought into contact with the capacitor 10, the application relay 15 is turned on as shown in FIG. 5A, and the capacitor 10 is charged from the power source 13 through the current limiting resistor 14 and the application relay 15. After the predetermined charging time ends, the transistor 21 is turned on by the drive circuit 23 as shown in (b), and the voltage charged in the capacitor 10 is discharged. After the predetermined discharge time is completed, the transistor 21 is turned off by the drive circuit 23, and the capacitor 10 is charged again as shown in (c). After repeating the operations (a) to (c) a predetermined number of times, the application relay 15 is turned off as shown in (d), and the discharge load test is terminated.

The capacitor 10 that has completed the discharge load test is sent to the next-stage insulation resistance measuring device 40 (see FIG. 8). As is well known, the insulation resistance measuring device 40 applies a predetermined direct current to the capacitor 10 and measures the leakage current (charging current) of the capacitor 10 after being fully charged, thereby measuring the capacitor 10 from the leakage current. The insulation resistance (IR) is obtained. Whether the capacitor is a good product or a defective product can be selected depending on whether the insulation resistance is higher than a reference value. When a defect (short) occurs in the capacitor 10 by the discharge load test, it can be reliably selected by measuring the insulation resistance.

In the above-described embodiment, as the inductance adjusting unit 24, the cable holding plate 28 that holds the cable 22 at a minute interval is fixed on the rail portion 26 of the base 25, and the terminal (first terminal) that holds the cable 22 at a wide interval on the transistor 21 side. (2 cable holding part) 21a is provided, but conversely to the above, the distance on the cable holding plate 28 side may be increased and the distance on the transistor 21 side may be reduced. Further, the inductance adjusting unit is not limited to the structure of the above embodiment, and any structure can be used as long as the distance between the pair of cables 22 can be adjusted by moving the intermediate member (sliding member). Good.

In the above embodiment, the insulated gate bipolar transistor is used as the switching means. However, the invention is not limited to this. For example, a relay capable of turning on / off a high voltage may be used.

It is a circuit diagram which shows an example of the discharge circuit by a general spark gap. It is a figure which shows the voltage change when discharging a capacitor | condenser using the discharge circuit using the spark gap shown in FIG. It is a circuit diagram which shows an example of the discharge load test apparatus of the capacitor | condenser concerning this invention. It is a top view of an inductance adjustment part, (a)-(c) shows each adjustment stage. It is an equivalent circuit diagram of a discharge circuit part. It is a reciprocating circuit diagram by the circular conductor for calculating an inductance. It is process drawing which shows the discharge load test method. It is a figure which shows the outline of an insulation resistance measuring apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Capacitor 11 Measurement terminal 12 Charging circuit part 13 High voltage power supply 14 Current limiting resistor 15 Application relay 20 Discharge circuit part 21 Bipolar transistor 21a Terminal (2nd cable holding part)
22 Cable 23 Drive circuit 24 Inductance adjustment section 25 Base 27 Slide member 28 Cable holding plate (first cable holding section)
40 Insulation resistance measuring device

Claims (4)

Power supply,
A pair of measuring terminals connected to the capacitor;
A charging circuit for applying the voltage of the power source to the capacitor via the measurement terminal;
In a capacitor discharge load test apparatus comprising: a discharge circuit unit that is connected in parallel with the charging circuit unit via the measurement terminal and that causes a discharge current when the capacitor is discharged to flow through the measurement terminal;
The discharge circuit part is
A pair of cables each having one end connected to the measurement terminal;
Switching means connected to the other end of the cable and short-circuiting / cutting off the discharge circuit unit;
An apparatus for adjusting a discharge load of a capacitor, comprising: an inductance adjusting unit capable of adjusting a desired discharge frequency by changing a distance between the pair of cables. 2. The capacitor discharge according to claim 1, wherein the switching means is an insulated gate bipolar transistor, and further includes a drive circuit for controlling the base current of the transistor to turn on / off the transistor. Load test equipment. The inductance adjusting unit is
A base having a first cable holding portion that holds the pair of cables at a minute interval at one end and a second cable holding portion that holds the pair of cables at a wider interval than the first cable holding portion at the other end. When,
The first cable holding portion is provided on the base so as to be slidable between the first cable holding portion and the second cable holding portion, and the distance between the pair of cables is set on one side facing the first cable holding portion. And a second adjustment unit that adjusts the distance between the pair of cables to the same distance as the second cable holding part on the other side facing the second cable holding part. The capacitor | condenser discharge load testing apparatus of Claim 1 or 2 characterized by the above-mentioned. 4. A capacitor selection device comprising an insulation resistance measuring device for measuring an insulation resistance of a capacitor in the next stage of the discharge load testing device according to claim 1.

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