JP2007155599A - Element test device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve one or more problems selected from a group of the following: equalizing ripple current of an element, such as each capacitor; making the current of an alternating-current power supply into necessary minimum; making a bias voltage into necessary minimum; equalizing the bias voltage applied to an element; and removing a voltage balance resistance, regarding a test of an element, such as a capacitor using the ripple current. <P>SOLUTION: This device comprises a first power supply (alternating-current power supply 6) which applies the ripple current to the elements (for example, capacitors C1-C6), a second power supply (direct current bias power supply 8) which applies a bias voltage to the elements, and a bias element which passes a direct current and blocks an alternating current. The elements are connected in series for the first power supply, and are connected to the second power supply in parallel through the bias element. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a test apparatus for an element such as a capacitor used for evaluation of the life, reliability, aging, failure mode, etc. of the element such as a capacitor, and more particularly, to a test apparatus for an element such as a capacitor using a ripple current or the like. About.

  A capacitor is mainly used for smoothing a voltage including a ripple. For example, a ripple current having a switching frequency as a fundamental component flows in a capacitor used in a smoothing circuit of a switching power supply. This ripple current causes heat generation of the capacitor and adversely affects the life of the capacitor.

  For this reason, it is necessary to perform a ripple test on the capacitor and evaluate the capacitor. Here, the ripple test means that while applying a specified voltage bias voltage to the capacitor under test for a predetermined time, a ripple current having a specified frequency and magnitude continues to flow, and the life of the capacitor, reliability, aging, This is a test for evaluating failure modes and the like.

With respect to testing of an element such as a capacitor, there are devices that give a ripple component or a bias voltage (Patent Documents 1 and 2).
JP 2003-264000 A JP 2001-16798 A

  Since such a ripple test may require a long period of time for a single test, it is desirable to perform a test on a large number of capacitors at the same time in order to improve the efficiency of the test. During the ripple test, it is necessary to maintain and manage the ripple current and bias voltage applied to the capacitor at specified values. In order to perform the ripple test easily, it is required to suppress the power supply to the capacitor and to test the plurality of capacitors at the same time. For the simultaneous testing, a configuration in which the plurality of capacitors are connected in series or in parallel is taken.

  FIG. 30 shows a conventional test apparatus in which capacitors are connected in series and parallel. In this test apparatus 100, capacitors C1, C2... C8, transformer 102, choke coil 104, AC power supply 106, DC bias power supply 108, voltage balance resistors R1, R2, R3, R4, connection cable 110, etc. The capacitors C1, C2,... C8 are configured by two systems of two parallel two series. A circuit portion in which a parallel circuit of capacitors C1 and C5 and a parallel circuit of capacitors C3 and C7 are connected in series is a first system circuit, and a parallel connection of capacitors C2 and C6 and a parallel connection of capacitors C4 and C8 are connected in series. This is the second system circuit.

  In such a test apparatus 100, for each ripple current and bias voltage applied to the capacitors C1, C2,... C8, if the capacitors C1, C2,. It is necessary to set the bias voltage equally. A ripple current is applied to each of the capacitors C1, C2,... C8 from the AC power source 106 through the transformer 102, and a bias voltage is applied from the DC bias power source 108. When the impedances of the capacitors C1, C2,... C8 are not equal, a choke coil 104 is installed to prevent a ripple current from flowing. In this case, since the capacitors in the first system and the second system are connected in series to the secondary side of the transformer 102, the same ripple current flows in the two systems.

  Incidentally, the first system and the second system are connected in parallel to the DC bias power supply 108 via the secondary winding of the transformer 102. The voltage drop due to the leakage current of the capacitor and the direct current flowing through the voltage balance resistor described later and the winding resistance on the secondary winding side of the transformer 102 is usually sufficiently small with respect to the bias voltage, and the variation in the voltage drop is Even smaller. For this reason, it can be considered that the same bias voltage is applied to each circuit of the first system and the second system.

  When the capacitors are connected in series, the bias voltage applied to each capacitor becomes a different voltage when the leak currents are not equal. In order to correct this, voltage balance resistors R1 to R4 are connected, and the bias voltages applied to the capacitors C1, C2,... C8 are set to be substantially equal.

  When there are impedance differences between the capacitors C1 and C5, the capacitors C2 and C6, the capacitors C3 and C7, and the capacitors C4 and C8 that are connected in parallel, a difference in the ripple current is generated according to the difference. For this reason, in the ripple test of the capacitors C1, C2,... C8, it is necessary to select the impedance and the leakage current value in advance for each of the capacitors C1, C2,. Further, when the impedance and leakage current of the capacitors C1, C2,... C8 change due to changes over time, there is a disadvantage that the test conditions change and an accurate test result cannot be obtained.

  Regarding the capacitor ripple test, when a plurality of capacitors of the same capacity and the same type are tested simultaneously under the same conditions, it is necessary to equalize the ripple current and bias voltage applied to each capacitor. The necessary conditions and issues are listed below.

  (1) When capacitors are connected in parallel, if there is variation in capacitor impedance or wiring impedance, the ripple current of each capacitor will vary, so there is a problem that testing cannot be performed for each capacitor under the same conditions. is there. In order to solve this problem, there is a method of selecting capacitors by impedance in advance. However, if the selection takes time and the impedance changes with time, highly reproducible data cannot be obtained.

  (2) When capacitors are connected in parallel, it is necessary to supply as many ripple currents as the number of parallel capacitors, and the AC power supply current must be increased. When the current of the AC power supply is increased, the voltage drop due to the impedance of the connection cable 110 increases. In particular, when the frequency of the AC power supply 106 is high, the voltage drop due to the inductance of the connection cable 110 becomes large. When the voltage drop is large, the voltage of the AC power source 106 must be increased in order to correct this, so a high-power AC power source is required, and the AC power source 106 becomes larger and expensive. Further, during the test, radio waves and magnetic flux of the frequency of the AC power source 106 are radiated from the output wiring of the AC power source 106, and the larger the current of the AC power source 106, the greater the interference with other electronic devices. Since the capacitor is used for smoothing the power supply, the impedance at the frequency of the ripple current is required to be low. For this reason, the AC power supply voltage is low in the ripple test, and the voltage is generally not a problem.

  (3) When capacitors are connected in series, the DC bias power supply voltage must be increased. In the case of 10 series, 10 times the DC voltage is required, so the DC bias power supply becomes expensive in proportion to the number of series. Moreover, since a high voltage is handled, there is a safety problem. The DC current flowing through the capacitor, that is, the leakage current is small, and the current of the DC bias power supply 108 does not matter.

  (4) When capacitors are connected in series, there is a problem in that the bias voltage of the capacitor varies due to variations in leakage current, and testing under the same conditions is not possible.

  (5) To avoid (4), a voltage balance resistor may be provided in parallel with the capacitor. If the resistance value of the voltage balance resistor is high, there is a possibility that variations in bias voltage cannot be corrected. If this voltage balance resistance is lowered, the current capacity of the DC bias power supply 108 must be increased, and the DC bias power supply 108 becomes large and expensive. Further, the power consumption in the voltage balance resistors R1, R2, R3, R4 cannot be ignored. When the power consumption increases, the heat generated by the voltage balance resistors R1, R2, R3, and R4 increases the temperature of the capacitor, which may adversely affect the life and performance of the capacitor. Therefore, it is desired to suppress variations in bias voltage without using a voltage balance resistor.

Summarizing such issues,
a equalizing ripple current of capacitors and other elements,
b Minimize the current of the AC power supply,
c Minimizing the voltage of the bias power supply,
d equalizing bias voltages applied to elements such as capacitors;
e removing the voltage balancing resistor;
Etc.

Therefore, an object of the present invention is to solve one problem or two or more problems selected from the above-mentioned problems with respect to testing of an element such as a capacitor using a ripple current.

  The configuration of a test apparatus for an element such as a capacitor according to the present invention that solves the above-described problems is as follows.

  According to a first aspect of the present invention, there is provided a device testing apparatus for supplying a ripple current to a device under test, a first power source for applying a ripple current to the device, and a second power source for applying a bias voltage to the device. A power supply and a bias element that passes a direct current and blocks an alternating current, the element is connected in series to the first power supply, and the element is connected to the second power supply via the bias element. It is the structure connected in parallel.

The element under test may be single or plural, and a ripple current is applied to the element from the first power supply and a bias voltage is applied from the second power supply. A bias element interposed between the element and the second power source allows a direct current to pass and prevents an alternating current.

  A second aspect of the present invention is a device testing apparatus for causing a ripple current to flow through an element under test, wherein the first power supply applies a ripple current to the element, a second power supply that generates a DC voltage, A biasing element provided between the second power supply and the element for passing the DC voltage and blocking the ripple current, and applying the ripple current from the first power supply to the element In addition, the DC voltage is applied from the second power source. According to such a configuration, a ripple current can be applied to the element and a DC voltage can be applied to efficiently test the element.

  According to a third aspect of the present invention, there is provided a capacitor testing apparatus for causing a ripple current to flow in a capacitor of an element under test, the ripple current being applied to the capacitor, a DC bias voltage being applied thereto, and the DC bias voltage being applied to the capacitor. And a bias element that blocks the ripple current is connected.

  According to a fourth aspect of the present invention, there is provided a capacitor testing apparatus for supplying a ripple current to a capacitor of a device under test, a first power supply for applying a ripple current to the capacitor, and a second power supply for generating a DC voltage. And a bias element that is provided between the second power source and the capacitor and passes the DC voltage and blocks the ripple current, and the capacitor receives the ripple current from the first power source. And the DC voltage is applied from the second power source.

  According to a fifth aspect of the present invention, there is provided a capacitor testing apparatus for causing a ripple current to flow in a capacitor of a device under test, a capacitor circuit composed of a plurality of capacitors, and a first that applies a ripple current to the capacitor circuit or the capacitor. A second power source that generates a DC voltage to be applied to the capacitor circuit or the capacitor, and is interposed between the second power source and the capacitor circuit or the capacitor. A bias element that passes the DC voltage and applies the same to the capacitor circuit or the capacitor and blocks the ripple current of the first power supply, and the bias element is configured by an inductor including a winding, For the current component where the inductor has the same value as the capacitor, the inductance is reduced, and the key is Is a configuration that is connected to the capacitor to be greater inductance for current component as a different value for Pashita.

  In the test apparatus, the bias element may have an impedance that is equal to or greater than an impedance value of the element.

  In the test apparatus, the bias element may be a diode.

  In the test apparatus, a leak current of the element may be detected from a DC voltage generated in the bias element or a DC voltage generated in a resistor connected to the bias element.

  The test apparatus may be configured to detect a ripple current of the element from an AC voltage generated in the bias element or an AC voltage generated in a resistor connected to the bias element.

  In the test apparatus, the bias element may be a transformer.

  In the test apparatus, the bias element may be a resonance circuit or a resonance element that resonates with the frequency of the first power supply.

  In the above-described configuration, if an element such as a capacitor is connected in series to the first power supply, the same ripple current flows through the element. According to such a configuration, the ripple currents of elements such as capacitors can be made equal, and the current of the first power supply can be minimized. If an element such as a capacitor is connected to the second power supply via a bias element, the direct current voltage applied to the element can be minimized, and the direct current voltage applied to the element can be made equal. Further, the voltage balance resistor can be omitted.

  If an inductor such as a transformer is used as the bias element, the characteristics can be utilized, the ripple current of the element such as a capacitor can be made equal, and the current of the first power supply can be minimized. In addition, when a device such as a capacitor is connected in parallel to the second power supply, the DC voltage applied to the device can be minimized and the DC voltage applied to the device can be made equal. Further, the voltage balance resistor can be omitted.

If an element having a large impedance is used as the bias element, the ripple current flowing through the element such as a capacitor can be made equal, so that the current of the first power supply can be minimized.

  According to the present invention, one or more of the following effects can be obtained.

  (1) The ripple current of the device under test such as a capacitor can be made equal.

  (2) The current of the first power supply that gives ripple current to the device under test such as a capacitor can be minimized.

  (3) The DC voltage of the second power source for applying a bias voltage to the device under test such as a capacitor can be minimized.

  (4) DC voltages applied as bias voltages to devices under test such as capacitors can be made equal.

(5) The voltage balance resistor can be eliminated, the circuit configuration is simplified, and the voltage balance resistor does not generate heat.

[First Embodiment]

  A first embodiment of a device testing apparatus according to the present invention will be described with reference to FIGS. 1 is a circuit diagram showing an example of a circuit used in the capacitor ripple test apparatus or ripple test method according to the first embodiment of the present invention, FIG. 2 is a circuit diagram showing an example thereof, and FIG. 3 is a simulation thereof. FIG. 4 is a circuit diagram illustrating another configuration example of the test apparatus according to the first embodiment, FIG. 5 is a diagram illustrating the simulation result, and FIG. 6 is a circuit diagram illustrating a configuration example of the bias element. 7 to 10 are circuit diagrams showing modifications of the first embodiment. In each drawing, common parts are denoted by the same reference numerals.

  For example, capacitors C 1, C 2, C 3, and C 4 are connected to the ripple test apparatus 2 as single or a plurality of devices under test. These capacitors C 1 to C 4 are connected in series to constitute a capacitor circuit 4. ing. In this capacitor circuit 4, in this embodiment, the capacitor C1 has a minus terminal on the connection point a side, the capacitors C1 and C2 have a plus terminal on the connection point b side, and the capacitors C2 and C3 have a minus terminal on the connection point c side. C3 and C4 are set to the plus terminal on the connection point d side, and the capacitor C4 is set to the minus terminal on the connection point e side. In this case, it does not matter whether or not the capacitors C1 to C4 are polar elements. However, when the element alone has no polarity, it depends on the polarity of the power source.

  In the ripple test apparatus 2, for example, an AC power source 6 is installed as a first power source, and a DC bias power source 8 is installed as a second power source. The AC power supply 6 generates a ripple current i or a ripple voltage to be applied to the capacitor circuit 4 or each of the capacitors C1 to C4. The configuration may be either a current source or a voltage source, and V1 is the voltage of the AC power source 6. Here, the ripple current i has a frequency and a specific level. The DC bias power supply 8 is a DC power supply that applies a DC bias voltage to each of the capacitors C1 to C4, and V2 is the DC voltage.

  Capacitors C <b> 1 to C <b> 4 are connected in series to the AC power supply 6, and a ripple current i is applied from the AC power supply 6. Further, a DC bias power supply 8 is connected to each of the connection points a, b, c, d, e of the capacitor circuit 4 via bias elements Z1, Z2, Z3, Z4, Z5, and a DC bias voltage is applied. Yes. As each of the bias elements Z1 to Z5, an element or a circuit having a characteristic of passing a direct current and blocking an alternating current is used.

  By installing the bias elements Z1 to Z5 having direct current passing / interrupting properties in this way, in this ripple test apparatus 2, if each bias element Z1 to Z5 is configured to block the ripple current i, each capacitor The ripple current i flowing through C1 to C4 is equal.

  Assuming that the bias elements Z1 to Z5 pass the ripple current i, the AC power supply 6 is connected to the bias elements Z1 to Z5 together with the capacitors C1 to C4 as a load. The series circuit of the bias elements Z1 and Z5 is directly connected to the AC power source 6, and the series circuit of the bias elements Z2 and Z4 is connected in parallel to the series circuit of the capacitors C2 and C3. Assuming that a ripple current flows through the bias elements Z2 and Z4, the ripple current flowing through the capacitors C1 and C4 is larger than the ripple current flowing through the capacitors C2 and C3. Such a variation in ripple current is easily eliminated if the bias elements Z1 to Z5 have a function of blocking the ripple current. In other words, each bias element Z <b> 1 to Z <b> 5 may be an element having a characteristic that exhibits a high impedance by the frequency f of the AC power supply 6.

  The leakage currents of the capacitors C1 to C4 are relatively small, and the voltage V2 of the DC bias power supply 8 is almost applied as it is to the capacitors C1 to C4 through the bias elements Z1 to Z5. However, since the leakage currents of the capacitors C1 to C4 are not completely absent, the bias elements Z1 to Z5 may be configured by elements or circuits that allow direct current to flow.

  When the leakage currents of the capacitors C1 to C4 vary, a DC voltage is generated in the bias elements Z1 to Z5 due to the leakage current, and the DC voltages applied to the capacitors C1 to C4 vary due to this voltage. It will be. In order to avoid this, the voltage generated in the bias elements Z1 to Z5 due to the leakage current may be set to a negligible level. For this purpose, for example, a bias element having low DC resistance may be used.

  Although it is known that the DC voltage applied to each of the capacitors C1 to C4 affects the life of the capacitors C1 to C4, it is required to accurately manage the DC voltage value even in the ripple test. In response to such a request, the DC resistance of the bias elements Z1 to Z5 may be lowered.

  In the first embodiment, resistors may be used for the bias elements Z1 to Z5. In the case of resistance, the DC resistance and the impedance at the frequency of the AC power supply 6 are the same, and if such test conditions are set, the resistance can be used for the bias elements Z1 to Z5.

  In the first embodiment, inductors may be used for the bias elements Z1 to Z5. That is, if an inductor having a larger impedance value at the frequency of the AC power supply 6 is used, it becomes difficult for a ripple current to flow through the bias elements Z1 to Z5. At a low frequency of about 50 [Hz] / 120 [Hz], the inductor is large and expensive, and the DC resistance tends to increase due to the large number of windings. Since a frequency of 10 kHz or higher is used, there is no inconvenience at a low frequency.

  In a temperature environment below the Curie point, a cored inductor can be used as the bias elements Z1 to Z5. The inductor with a core has an advantageous property as a bias element because it has a higher impedance with respect to alternating current and a lower resistance with respect to direct current than an air core inductor.

  When resistors are used for the bias elements Z1 to Z5, the influence of temperature is smaller than that of the cored inductor, and the degree of freedom of the ambient temperature is increased.

  In the first embodiment, diodes can be used as the bias elements Z1 to Z5 as shown in FIG. FIG. 2 is a circuit diagram (simulation circuit) showing the ripple test apparatus 2 using the diodes D1 to D5.

  In this case, when the AC power supply 6 and the DC bias power supply 8 are set to 0 [V], and the voltage of the DC bias power supply 8 is increased from 0 [V] to V2 [V], each capacitor C1 to C4 has the voltage {V2- ( 2 × Vf)}. However, Vf is a forward voltage of a diode.

  During several cycles after the AC power supply 6 is started, the diodes D1 to D5 have a rectifying action on the ripple current, and thereafter, charging of the capacitors C1 and C4 is completed. In this case, when the AC power supply 6 is operated and the instantaneous voltage reaches a peak and the capacitor C1 side becomes + and the capacitor C4 side becomes-, the capacitor C4 is charged through the path of the AC power supply 6 → D1 → DC bias power supply 8 → D4. The Further, when the capacitor C1 side becomes-and the capacitor C4 side becomes +, the capacitor C1 is charged through the path of the AC power source 6 → D5 → DC bias power source 8 → D2.

  As described above, in the simulation circuit using the diodes D1 to D5, the capacitors C1 to C4 = 1 [μF], the DC bias voltage V2 = 100 [V], the frequency f = 100 [kHz] of the AC power supply 6, and the voltage V1 = 10. If [Vp−p], the ripple current i = 1.6 [Ap−p].

  The result of such a simulation is as shown in FIG. 3A shows the voltages of the capacitors C1 to C4, FIGS. 3B and 3C show the currents of the diodes D1 to D5, and the horizontal axis represents time.

  Current flows through the diodes D1 and D4 in the section of 5 [μs] from the start of power supply, and the capacitor C4 is charged by the current. In the next 5 [μs] section, current flows through the diodes D2 and D5, and the capacitor C1 is charged by the current. In this case, the average value of the DC voltage of the capacitors C2 and C3 is 100 [V], whereas the average value of the DC voltage of the capacitors C1 and C4 is 102 [V], which is 2% higher than the initial voltage. It has become.

  As is apparent from this simulation, this difference in voltage becomes significant when testing at a lower bias voltage, but it is practically negligible under the above simulation conditions.

  When the ripple voltage of the capacitors C1 to C4 is smaller than the forward voltage Vf of the diodes D1 to D5, no rectification action occurs. However, variations in the forward voltage Vf of the diodes D1 to D5 and the bias voltage of the capacitors C1 to C4 depend on the leakage currents of the capacitors C1 to C4. When the bias voltage is low, variations in the bias voltage cannot be ignored.

  Such a phenomenon can be verified with the simulation circuit shown in FIG. When the capacitors C1 to C4 = 1000 [μF], the DC bias voltage V2 = 100 [V], the frequency f = 100 [kHz] of the AC power source 6 and the voltage V1 = 100 [mVp-p], the ripple current i = 16 [ Ap-p]. In order to simulate the leakage current of the capacitor C1 to 100 [μA], a resistor R1 is added.

  Such a simulation result is shown in FIG. In FIG. 5, (A) is the instantaneous voltage of the capacitors C1 to C4, (B) and (C) are the instantaneous currents of the diodes D1 to D5, and the horizontal axis is time.

  In this case, the generation of ripple voltage cannot be confirmed. With DC voltage, capacitor C1 is 99 [V], capacitors C2 and C4 are 99.5 [V], and capacitor C3 is 100 [V]. There is a variation of 5 [V] (± 0.5 [%]). As is clear from the simulation results, the above conditions are negligible.

  In the first embodiment, bias elements Z1 to Z5 having inductors and capacitors in parallel may be used. FIG. 6 is a circuit diagram illustrating a configuration example of bias elements Z1 to Z5 including an LC parallel circuit of an inductor L and a capacitor C. In such a configuration, if the parallel resonance frequency of the LC parallel circuit is made to coincide with the ripple frequency, the impedance becomes high at that frequency, so that the ripple current hardly flows through the bias elements Z1 to Z5. In addition, since the direct current resistance is negligible (almost zero), there is an advantage that the direct current bias voltage is hardly affected.

  The number of capacitors, which are the elements under test, may be any number of one or more, but in the case of an odd number, the AC power supply 6 superimposes a ripple current on a DC voltage substantially equal to the DC bias voltage of the DC bias power supply 8. Is required, so an even number is desirable.

  When a single capacitor C1 is used, it can be configured as shown in FIG. FIG. 7 shows a configuration example when a single capacitor C1 is used. The AC power supply 6 needs to generate a DC voltage (≈V2) corresponding to the DC bias voltage V2 applied from the DC bias power supply 8 to the capacitor C1 in addition to the ripple current. Even in such a configuration, a ripple test of the capacitor C1 can be performed.

  Further, when the above-described DC voltage (≈V2) is not generated in the AC power source 6, a capacitor C5 may be added as shown in FIG.

  When two capacitors C1 and C2 are used as the device under test, the circuit configuration shown in FIG. As described above, when the number of capacitors is an even number, the AC power supply 6 does not need to generate the above-described DC voltage. The same applies to the circuit shown in FIG.

  In the first embodiment, the AC power supply 6 is directly added to the capacitors C1 to C4. However, as shown in FIG. 10, the AC power supply 6 is connected to the capacitor circuit 4 via the transformer 10. It is good. The AC power supply 6 connected to the capacitor circuit 4 requires an AC power supply that can extract a large current at a relatively low voltage. In that case, a step-down transformer can be used, and if the step-down transformer is used, the output current of the AC power supply 6 can be further reduced. As a result, even if the connection cable 11 between the AC power supply 6 and the transformer 10 is lengthened, radio wave radiation, magnetic flux leakage, and voltage drop can be reduced. Furthermore, if the configuration using the transformer 10 is used, safety can be improved, and an effect of reducing or avoiding the influence due to the difference in ground potential between the capacitor circuit 4 and the DC bias power supply 8 can be expected.

  According to the first embodiment described above, the following effects can be obtained.

  (1) In the configuration in which the capacitors C1 to C4 are connected in series to the AC power source 6, even when the impedance and wiring impedance of the capacitors C1 to C4 are uneven (variation), the same ripple current is supplied to the capacitors C1 to C4. Can be given. Even when a plurality of capacitors C1 to C4 are tested at the same time, the current supplied from the AC power supply 6 to the capacitors C1 to C4 may be smaller than when the capacitors C1 to C4 are connected in parallel. Descent can be suppressed. Moreover, a step-down transformer may be used together like the transformer 10, and if a step-down transformer is used together, the output current of the AC power supply 6 can be further reduced.

  (2) In the configuration in which the capacitors C1 to C4 are connected in parallel to the DC bias power supply 8, the capacitors C1 to C4 can lower the voltage V2 of the DC bias power supply 8 and make the DC bias voltage V2 equal. it can. Even if there are variations in the leakage currents of the capacitors C1 to C4, the DC bias voltage V2 can be made equal, and there is no need to balance the voltages by connecting voltage balancing resistors in parallel to the capacitors C1 to C4. .

[Second Embodiment]

  Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 11 is a circuit diagram illustrating an example of a ripple test apparatus according to the second embodiment, and FIG. 12 is a diagram illustrating an equivalent circuit of the transformer.

  In this embodiment, six sets of capacitors C1 to C6 are used as a plurality of elements to be tested. These capacitors C1 to C6 are divided into two, and capacitors C1, C2, and C5 are paralleled, and capacitors C3, C4, and C6 are arranged. The capacitor circuit 4 is configured by parallelizing them and serializing them, and the ripple currents for the capacitors C1, C2, and C5 are made uniform by the transformers 12 and 14, and similarly, the ripple currents for the capacitors C3, C4, and C6 by the transformers 16 and 18 Is made uniform. In addition, as shown in FIG. 12, the transformers 12, 14, 16, and 18 can be constituted by windings L201 and L202, for example.

  For example, a single-winding transformer is used for the transformers 12, 14, 16, and 18. A ripple current from the AC power source 6 is injected from the intermediate taps of the transformers 12, 14, 16, and 18, and the windings centered on the intermediate taps are used. The ripple current for the capacitors C1 to C6 is made uniform by the turn ratio of the wires. The transformer 12 connected to the capacitors C1 and C2 has the same turn ratio (1: 1) with the intermediate tap as the center. The same applies to the transformer 16 connected to the capacitors C3 and C4. The transformer 14 connected to the intermediate tap of the transformer 12 and the capacitor C5 has a turn ratio (m: n) set around the intermediate tap. In this case, if each ripple current of the capacitors C1, C2, and C5 is i, the turns ratio of the transformer 14 is 2t on the transformer 12 side and i is supplied to the capacitor C5 side. ), M may be the number of capacitors connected in parallel to the tip of the n-side winding, and n may be the number of capacitors connected in parallel to the tip of the m-side winding. That is, in the transformer 14, m: n may be 1: 2, for example. Such a configuration is the same in the transformer 18. If the ripple current flowing through each of the capacitors C1 to C6 is i, the ripple current injected from the AC power supply 6 connected to the intermediate taps of the transformers 14 and 18 is 3i.

  An inductor LB is used as a bias element, and the DC bias power supply 8 applies a DC bias voltage V2 to the capacitors C1, C2, C5 and capacitors C3, C4, C6 of the capacitor circuit 4 through the inductor LB.

  Here, paying attention to the current flowing through the winding L1 of the transformer 12 and the closed circuit of the capacitors C1 and C2, there is a current ic that flows equally in the capacitors C1 and C2 and a current in that flows in the reverse direction in the capacitors C1 and C2. The current of this closed circuit can be considered as the sum of these currents by the superposition theory. The current flowing in the capacitor C1 is the sum of the current ic and the current in (ic + in), the current flowing in the capacitor C2 is the difference between the current ic and the current in (= ic-in), and the current flowing in each of the capacitors C1 and C2 is ( 2 × in) = {(ic + in) − (ic−in)}, a current difference is generated and becomes non-uniform.

  When a current flows through the winding L1 and a magnetic flux is generated in the magnetic circuit of the transformer 12, a self-inductance of the winding L1 generates a counter electromotive force in the direction that cancels the magnetic flux. Considering the influence of the current ic in the winding L1, the direction of the magnetic flux due to the current flowing toward the capacitor C1 and the direction of the magnetic flux due to the current flowing toward the capacitor C2 are opposite and have the same magnitude. The magnetic flux will be canceled out. As a result, since the current ic does not generate a magnetic flux in the winding L1, no back electromotive force is generated in the winding L1. Therefore, even if this current component flows, a voltage drop due to the winding L1 does not occur.

  However, if the impedances of the capacitors C1 and C2 are different, the voltage drops generated in the capacitors C1 and C2 when the current ic flows have different values (difference voltages). The current in flowing in the capacitors C1 and C2 in the reverse direction depends on the above-described difference voltage applied to the winding L1. Considering the influence of the current in in the winding L1, the current in generates a magnetic flux in the winding L1 and generates a counter electromotive force. Accordingly, the winding L1 has a suppression effect on the current in, and if the inductance of the winding L1 is sufficiently large, the currents of the capacitors C1 and C2 can be made substantially equal.

  In this way, when a ripple current is injected into the intermediate tap of the transformer 12, currents corresponding to substantially the same ripple current can be obtained from both ends. Therefore, connecting the intermediate tap of a new transformer to both ends of the transformer 12 in a plurality of stages. If it is repeated, approximately equal 2 n ripple currents can be obtained.

  Further, if the winding ratio of m: n is used as in the winding L2 of the transformer 14, the current can be shunted to m: n, so the number of capacitors is not limited to 2 to the nth power and can be freely selected. .

  Next, focusing on the ripple current flowing in the winding L2 of the transformer 14, the current flowing from the intermediate tap to the winding L1 side of the transformer 12 is Il, and the current flowing from the intermediate tap to the capacitor C5 side is Ir.

  At this time, if the number of turns of the winding L2 of the transformer 14 is m and n, the magnetic flux in the winding L2 is canceled if the current on the turns m and turns n side is set to m × Il = n × Ir. No voltage drop occurs on the line L2. However, when m × I1 ≠ n × Ir, a magnetic flux proportional to the current difference is generated in the winding L2, so that a voltage drop corresponding to that occurs in the winding L2. As a result, I1 and Ir is adjusted so that m × Il≈n × Ir. Since a large ripple current flows through the windings L1 to L4, the DC resistance values of the windings L1 to L4 are low.

  If the secondary side of the step-down transformer is used as the AC power source 6, the DC resistance becomes low.

  Since any DC resistance is low resistance, even if the leakage currents of the capacitors C1 to C6 vary, the bias voltages of all the capacitors C1 to C6 are almost equal. Therefore, in order to reduce the ripple current flowing into the DC bias power supply 8, an inductor LB is illustrated as a bias element. If an LC parallel resonance circuit is used as a bias element and the resonance frequency is made to coincide with the ripple current frequency, the ripple current flowing through the DC bias power supply 8 can be reduced.

  According to the second embodiment described above, the following effects can be obtained.

  (1) Even if the impedance of the capacitors C1 to C6 or the wiring impedance varies, the same ripple current can be applied to the capacitors C1 to C6.

  (2) Since the capacitors C1 to C6 are connected in parallel to the DC bias power supply 8, there is no need to increase the bias voltage V2. Further, even if the leakage currents of the capacitors C1 to C6 vary, the bias voltages can be made equal. For this reason, it is not necessary to add a voltage balance resistor to the capacitors C1 to C6.

[Third Embodiment]

  Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 13 is a circuit diagram showing an example of a ripple test apparatus according to the third embodiment.

  In this embodiment, the transformers 20 and 30 are each composed of a four-winding transformer. Black circles attached to the transformers 20 and 30 indicate the winding direction. The winding ratio of the four windings L201, L202, L203, and L204 or the windings L301, L302, L303, and L304 is set to 1: 1: 1: 1, for example.

  The ripple current supplied from the AC power supply 6 passes through the transformers 20 and 30 and is injected into the capacitors C1 to C4. A resistor R1 that constitutes a damping resistor is connected between the capacitors C1 and C2, and a resistor R2 that similarly constitutes a damping resistor is connected between the capacitors C3 and C4. The DC bias power supply 8 supplies a bias voltage to all the capacitors C1 to C4 through an inductor LB which is a bias element. The inductor LB is composed of, for example, a choke coil.

Assuming that the ripple currents flowing upward in the capacitors C1, C2, C3, and C4 are i1, i2, i3, and i4, and the currents flowing in the inductor LB and the resistors R1 and R2 are ignored, the capacitors C1 and C2 and the capacitors C3 and C4 Are connected in series,
i1 + i2 = i3 + i4 (1)
The relationship holds.

By the way, in the transformer 20, the back electromotive force is not generated if the sum of all currents flowing from the black circle side is 0 by the same function as the transformer 12 shown in FIG. If the total current is not zero, back electromotive force is generated in the direction to cancel it, that is, the inductance is generated and the total current is zero. Therefore, the transformer 20
i1 + i3 = i2 + i4 (2)
Work to be close to. Similarly, the transformer 30
i1 + i4 = i2 + i3 (3)
Work to be close to. These results
From (1) and (2), i1 = i4
From (1) and (3), i1 = i3
From (2) and (3), i1 = i2
It works to be. In other words, with such a connection, the transformers 20 and 30 work so as to be close to i1 = i2 = i3 = i4.

  In order to obtain such a current balance effect, the frequency f of the AC power source 6 may be set sufficiently higher than the resonance frequency of the inductances of the transformers 20 and 30 and the capacitors C1 to C4. When the capacitances of the capacitors C1 to C4 are small and the frequency of the AC power supply 6 is close to the resonance frequency, current balance is expected to deteriorate due to resonance. To prevent this, resistors R1 and R2 are added. do it. When the frequency of the AC power supply 6 is higher than the resonance frequency of the inductances of the transformers 20 and 30 and the capacitors C1 to C4, the resistors R1 and R2 are unnecessary.

  In this embodiment, the two transformers 20 and 30 are used to balance the AC currents of the capacitors C1 to C4. Similarly, n transformers are used to ripple the 2 × n capacitors. It is possible to balance the current. Also according to this embodiment, the same effect as that of the second embodiment can be obtained.

[Fourth Embodiment]

  Next, a fourth embodiment of the present invention will be described with reference to FIG. 14, FIG. 15, and FIG. FIG. 14 is a circuit diagram showing an example of a ripple test apparatus according to the fourth embodiment, FIG. 15 is a diagram showing a configuration example of an impedance element, and FIG. 16 is a test apparatus to which a detection resistor for leakage current and ripple current is added. It is a circuit diagram which shows the example of a structure.

  In this embodiment, capacitors C1, C2, and C3 which are elements to be tested are used, and bias elements Z1, Z2, and Z3 having a large impedance Zr are connected in series to the capacitors C1 to C3, and capacitors C1 to C3 are connected. The ripple current of C3 is made uniform. That is, bias elements Z1, Z2, and Z3 having the same impedance and a sufficiently higher impedance Zr than the impedance Z of the capacitors C1 to C3 are connected in series to the capacitors C1 to C3, and these are connected in parallel. Yes. The AC power supply 6 and the DC bias power supply 8 are connected in series. For example, the bias elements Z1 to Z3 can be configured by an inductor L or a resistor R as shown in FIG.

  According to such a configuration, since the AC power supply 6 is connected in series to the DC bias power supply 8, the DC bias power supply 8 needs a DC power supply capable of flowing a ripple current. In that case, for example, a capacitor may be added in parallel with the DC bias power supply 8.

When the ripple currents flowing through the capacitors C1, C2, and C3 are i1, i2, and i3, respectively, the ripple current in that flows through the capacitor Cn (n = 1, 2, 3) is
in = V1 ÷ {Zr−j / (ωCn)} (4)
It becomes. If the value of Zr is selected so that | Zr | >> | j / (ωCn) |
in ≒ V1 ÷ Zr (5)
Since the impedances Zr of the bias elements Z1 to Z3 are equal, i1≈i2≈i3.

  Here, it is assumed that resistors are used for the bias elements Z1 to Z3. As described above, when setting so that | Zr | >> | j / (ωCn) |, each impedance Zr of the bias elements Z1 to Z3 has a relatively high resistance. However, a large ripple current flows through the bias elements Z1 to Z3, and the power loss of the high resistance bias elements Z1 to Z3 increases. In addition, when there are variations in the leakage currents of the capacitors C1 to C3, the DC bias voltages applied to the capacitors C1 to C3 in the high resistance bias elements Z1 to Z3 also depend on the variations.

  Therefore, if an inductor is used for the bias elements Z1 to Z3, power loss can be reduced. Since the inductor has a small DC resistance, the bias voltages of the capacitors C1 to C3 are equal even if the leakage currents of the capacitors C1 to C3 vary. When the frequency of the AC power supply 6 is high, the wiring impedance to the capacitors C1 to C3 may be higher than the impedance of the capacitors C1 to C3. In such a case, if the wiring impedance is made uniform, the wiring itself can be used as the bias elements Z1 to Z3 or as a part of the bias elements Z1 to Z3, and the capacitors C1 to C3. A simple and inexpensive ripple test can be realized.

  If variation in impedance of each bias element Z1 to Z3 is small, variation in ripple current flowing in capacitors C1 to C3 can be suppressed even if impedance of capacitors C1 to C3 varies.

  Further, as shown in FIG. 16, if resistors R1, R2, and R3 are connected in series to the bias elements Z1 to Z3, the DC voltage generated at each resistor R1, R2, and R3 and its resistance value R The leakage current of each of the capacitors C1 to C3 can be known individually. Further, if the resistance values of the bias elements Z1 to Z3 are known, the capacitors C1 are similarly detected from the DC voltage generated in the bias elements Z1 to Z3 and the resistance values without inserting the resistors R1 to R3. It is also possible to detect a leak current of .about.C3.

  Similarly, the ripple current flowing in each of the capacitors C1 to C3 can be individually known from the AC voltage generated in each of the resistors R1 to R3 and the resistance value R thereof. In addition, if the resistance values of the bias elements Z1 to Z3 are known, the capacitors R1 to Z3 are inserted from the AC voltage generated in the bias elements Z1 to Z3 and the resistance values without inserting the resistors R1 to R3. The ripple current flowing in C1 to C3 can also be detected.

  According to the fourth embodiment described above, the following effects can be obtained.

  (1) Even when the impedances of the capacitors C1 to C3 vary, the same ripple current can be applied to the capacitors C1 to C3.

  (2) When the bias elements Z1 to Z3 are realized by elements having a higher impedance than the wiring impedance, the same ripple current can be given to the capacitors C1 to C3 even if the wiring impedance varies.

  (3) When the frequency of the AC power supply 6 is high, if the wiring impedance of the wiring connected to each of the capacitors C1 to C3 is made uniform, the wiring impedance can be used as the bias elements Z1 to Z3, and the test apparatus can be used easily and easily. It can be made cheap.

  (4) According to the configuration in which the capacitors C1 to C3 are connected in parallel to the DC bias power supply 8, there is no need to increase the DC bias voltage, and even if the leakage currents of the capacitors C1 to C3 vary, The DC bias voltage can be made equal. For this reason, it is not necessary to provide a voltage balance resistor in parallel with the capacitors C1 to C3.

[Fifth Embodiment]

  Next, a fifth embodiment of the present invention will be described with reference to FIGS. FIG. 17 is a circuit diagram illustrating an example of a ripple test apparatus according to the fifth embodiment, FIG. 18 is a circuit diagram illustrating the simulation circuit, and FIGS. 19 to 21 are diagrams illustrating the simulation results.

  In this embodiment, capacitors Cr1, Cr2, Cr3 and inductors L1, L2, L3 are used as bias elements. That is, the AC power source 6 is connected to the capacitor C1 via the capacitor Cr1, and the DC bias power source 8 is connected to the capacitor C1. The AC power source 6 is connected to the capacitor C2 via the capacitor Cr2. In addition, a DC bias power supply 8 is connected via the inductor L2, and an AC power supply 6 is connected to the capacitor C3 via the capacitor Cr3, and a DC bias power supply 8 is connected via the inductor L3. It is connected.

  If the bias element (impedance element) is composed only of the capacitors Cr1, Cr2, and Cr3, these capacitors Cr1, Cr2, and Cr3 cut off direct current. Therefore, the direct current bias voltage V2 is changed to the capacitors C1 to C3 by interposing the inductors L1 to L3. It is comprised so that it may be applied to. If inductors L1 to L3 having high impedance with respect to the frequency of the AC power supply 6 are used, it is possible to prevent the ripple current from flowing into the DC bias power supply 8 side.

  Since the inductors L1 to L3 and the capacitors Cr1 to Cr3 constitute the LC resonance circuit 40, when the resonance frequency and the frequency of the AC power supply 6 are made to resonate with each other, the impedance when the LC resonance circuit 40 is viewed from the capacitors C1 to C3. Zo becomes higher than the impedance of the capacitors Cr1 to Cr3. This corresponds to the case where the impedance Zr of the bias elements Z1 to Z3 of the fourth embodiment (FIG. 14) is increased, and a uniform ripple current can be supplied to the capacitors C1 to C3.

  Therefore, a simulation for this embodiment will be described with reference to FIG. 18, FIG. 19, FIG. FIG. 18 is a circuit diagram showing the simulation circuit, and FIGS. 19 to 21 are diagrams showing resonance results. In FIG. 18, the same parts as those in FIG. 17 are denoted by the same reference numerals and the numerical values used in the simulation are appended.

  In the simulation circuit shown in FIG. 18, the capacitances of the capacitors Cr1 to Cr3 are 1 [μF] (center value), and the inductors L1 to L3 are 1 [μH] (center value). Therefore, the resonance frequencies of the capacitors Cr1 to Cr3 and the inductors L1 to L3 are about 159 [kHz]. The resistors R1, R2, and R3 are direct current resistors of the inductors L1 to L3, and the resistance value is 10 [mΩ]. The inductors L4, L5, and L6 are wiring inductances between the capacitors C1 to C3 and the capacitors Cr1 to Cr3, and the center value thereof is 1 [μH].

  19 to FIG. 21, the horizontal axis represents the frequency f = 50 [kHz] to 800 [kHz] of the AC power supply 6 in logarithm, and the vertical axis represents the ripple current value of any of the capacitors C1 to C3. The logarithmic display is also used.

  FIG. 19 shows the simulation result of FIG. It can be seen that, at the resonance frequency of the capacitors Cr1 to Cr3 and the inductors L1 to L3, about 159 [kHz], the ripple current value is a constant value regardless of the change of the parameters. That is, when the frequency of the AC power supply 6 is about 159 [kHz], the ripple current can be made constant.

  FIG. 20 is a simulation result when the center value of the capacitances of the capacitors C1 to C3 is 100 times that of FIG. Similarly to the simulation result shown in FIG. 19, at the resonance frequency of the capacitors Cr1 to Cr3 and the inductors L1 to L3, about 159 [kHz], it can be seen that the ripple current value is a constant value regardless of the change of the parameter. .

  FIG. 21 shows a simulation result when the center value of the capacitance of the capacitors C1 to C3 is 100 times that of FIG. 18 and the inductors L1 to L3 are 1000 times that of FIG. The resonance frequencies of the capacitors Cr1 to Cr3 and the inductors L1 to L3 are outside the display. As is apparent from this result, when the resonance is not used, the ripple current value may not become a constant value.

  According to the fifth embodiment described above, the following effects can be obtained.

  (1) If the resonance points of the capacitors Cr1 to Cr3 and the inductors L1 to L3 coincide with the frequency of the AC power supply 6, the capacitors C1 to C3 are constant even if the wiring inductance and the capacitance of the capacitors C1 to C3 vary. Ripple current can be supplied.

  (2) Since the capacitors C1 to C3 are connected in parallel to the DC bias power source 8, there is no need to increase the DC bias voltage V2. Further, even if the leakage currents of the capacitors C1 to C3 vary, the DC bias voltage applied to the capacitors can be made equal. For this reason, it is not necessary to provide a voltage balance resistor in parallel with the capacitors C1 to C3.

[Sixth Embodiment]

  Next, a sixth embodiment of the present invention will be described with reference to FIG. FIG. 22 is a circuit diagram showing an example of a ripple test apparatus according to the sixth embodiment.

  In this embodiment, three DC bias power supplies 81, 82, and 83 are used as a plurality of second power supplies to equalize the bias voltage. Capacitors C1, C2, C3, C4, C5, and C6 as elements to be tested are connected in series to the AC power supply 6, DC bias power supplies 81, 82, and 83 are connected in series, and DC bias voltages V2 to V2 are connected. V4 is applied to the capacitors C1 to C6 via the bias elements Z1, Z2, Z3, Z4, and Z5. In this case, the bias elements Z1, Z2, Z3, Z4, and Z5 include a resistor R shown in FIG. 23A, an inductor L shown in FIG. 23B, or an LC parallel resonant circuit shown in FIG. Consists of. The DC resistance values of these bias elements Z1 to Z5 are low enough that the voltage drop of the bias elements Z1 to Z5 when the leakage current of the capacitors C1 to C6 flows is negligible with respect to the DC bias voltage of the capacitors C1 to C6. Resistance value. In such a case, substantially the same effect can be obtained regardless of the connection method such as the bias elements Z2 and Z3 or the connection method such as the bias elements Z4 and Z5. Further, the impedance of the bias elements Z1 to Z5 at the frequency f of the AC power supply 6 is set to a high impedance such that the impedance of the capacitors C1 to C6 due to the frequency of the AC power supply 6 can be ignored.

  With such a configuration, since the capacitors C1 to C6 are connected in series to the AC power source 6, the ripple currents flowing through the capacitors C1 to C6 are uniform. In terms of DC, the capacitors C5 and C6 are connected in parallel to the DC bias power supply 81, the capacitors C3 and C4 are connected to the DC bias power supply 82, and the capacitors C1 and C2 are connected to the DC bias power supply 83 in parallel. Therefore, if each DC bias voltage is V2 = V3 = V4, the DC bias voltages of the capacitors C1 to C6 become uniform.

  According to the sixth embodiment described above, the following effects can be obtained.

  (1) It can be composed of n DC bias power supplies for 2n capacitors.

  (2) Even when the impedance of the capacitors C1 to C6 or the wiring impedance varies, the same ripple current can be applied to the capacitors C1 to C6.

  (3) Since the capacitors C1 to C6 are connected in series to the AC power supply 6, it is not necessary to increase the current of the AC power supply 6 even when a plurality of capacitors C1 to C6 are tested simultaneously. Therefore, the voltage drop due to the wiring does not increase.

  (4) Since two capacitors are connected in parallel to one DC bias power source, the DC bias voltage can be made equal even if the leakage currents of the capacitors C1 to C6 vary. For this reason, it is not necessary to connect a voltage balance resistor to the capacitors C1 to C6.

[Seventh Embodiment]

  Next, a seventh embodiment of the present invention will be described with reference to FIG. FIG. 24 is a circuit diagram showing a ripple test apparatus according to the seventh embodiment.

  This embodiment is a combination of the first embodiment (FIG. 1) and the second embodiment (FIG. 11). Capacitors C1 to C4 that are elements to be tested are connected in series, and capacitors C5 to C8 that are elements to be tested are also connected in series to form capacitor circuits 401 and 402, respectively. The AC power supply 6 is connected in parallel to these two sets of capacitor circuits 401 and 402 through an intermediate tap of the transformer 50. Accordingly, the capacitors C1 to C8 are connected in parallel to the DC bias power supply 8 through the bias elements Z1 to Z6, the AC power supply 6, and the windings of the transformer 50.

  The DC resistance values of the bias elements Z1 to Z6 and the AC power supply 6 are set to low resistance values such that the voltage drop when the leakage current of the capacitors C1 to C8 flows can be ignored with respect to the DC bias voltages of the capacitors C1 to C8. To do. In addition, the impedance of the bias elements Z1 to Z6 at the frequency of the AC power supply 6 is set so as to be a large value such that the impedance of the capacitors C1 to C8 can be ignored.

  Since the capacitors C1 to C4 are connected in series to the AC power supply 6, the ripple currents flowing through them are the same, and similarly, the ripple currents flowing through the capacitors C5 to C8 are also the same. The ripple currents of these two systems are made uniform by the same action as in the second embodiment (FIG. 11). As a result, the ripple currents of the capacitors C1 to C8 become equal. Further, since the capacitors C1 to C8 are connected in parallel in terms of DC, the DC bias voltages of all the capacitors C1 to C8 are also equal.

  According to the seventh embodiment described above, the following effects can be obtained.

  (1) Even when the impedances or wiring impedances of the capacitors C1 to C8 vary, the same ripple current can be applied to the capacitors C1 to C8. Since the capacitors C1 to C4 and the capacitors C5 to C8 are connected in series to the AC power supply 6, it is not necessary to increase the current of the AC power supply 6 even when a plurality of capacitors are tested simultaneously. Therefore, voltage drop due to wiring can be suppressed.

  (2) Since the capacitors C1 to C8 are connected to the DC bias power supply 8 in parallel in DC, the DC bias voltages can be made equal even if the leakage currents of the capacitors C1 to C8 vary. . For this reason, it is not necessary to provide a voltage balance resistor in parallel with the capacitors C1 to C8.

[Eighth Embodiment]

  Next, an eighth embodiment of the present invention will be described with reference to FIGS. FIG. 25 is a circuit diagram showing a ripple test apparatus according to the eighth embodiment, and FIG. 26 is a circuit diagram showing a specific example thereof.

  In this embodiment, the element circuit 400 is configured by connecting test elements Z11 to Z14 in series. A current source 60 is connected as a first power source, and the current source 60 may be either AC or DC. A voltage source 80 is connected as a second power source, and this voltage source 80 may be either AC or DC. When the current source 60 and the voltage source 80 are constituted by an AC power supply, the frequencies of the voltages V1 and V2 may be made different.

  The bias elements Za, Zb, Zc, Zd, and Ze are elements whose impedance changes depending on the frequency, or whose impedance changes between direct current and alternating current, and with respect to the frequency (or direct current) of the voltage V2 of the voltage source 80, An element having a lower impedance than the test elements Z11 to Z14 and a higher impedance than the test elements Z11 to Z14 is selected for the frequency (or direct current) of the current source 60.

  According to such a configuration, an equal current can be passed from the current source 60 to the test elements Z11 to Z14, and the voltage V2 can be applied from the voltage source 80.

  In this case, each of the test elements Z11 to Z14 or the bias elements Za to Ze may be a single element or a circuit composed of a plurality of elements.

  As a modification of the eighth embodiment, as shown in FIG. 26, test elements Z11 to Z14 can be composed of inductors L11 to L14, and bias elements Za to Ze can be composed of capacitors Ca to Ce. In this case, the element circuit 400 constitutes an inductor circuit.

  According to such a configuration, it is possible to conduct an energization test in which the same bias current is applied to a plurality of coils (inductors) as elements to be tested and the same voltage waveform is applied with a small number of power supplies.

[Ninth Embodiment]

  Next, a ninth embodiment of the present invention will be described with reference to FIG. FIG. 27 is a circuit diagram showing a ripple test apparatus according to the ninth embodiment.

  In this embodiment, bias elements Zr1, Zr2, and Zr3, which are impedance elements, are connected in series to the test elements Z21, Z22, and Z23, respectively, and a current flowing from the power supply 600 is caused to flow equally to the test elements Z21, Z22, and Z23. In this configuration, the voltage V2 from the power source 800 is applied. In this case, the voltages V1 and V2 may be alternating current or direct current, but may be different frequencies.

  The bias elements Zr1, Zr2, Zr3 connected in series to the test elements Z21, Z22, Z23 select an impedance higher than the impedance of the test elements Z21, Z22, Z23 at the frequency (or DC) of the voltage V1 of the power supply 600, Variation in impedance elements constituting the bias elements Zr1, Zr2, and Zr3 is suppressed to a small value. The bias elements Zr1, Zr2, and Zr3 set impedance lower than that of the test elements Z21, Z22, and Z23 at the frequency (or direct current) of the voltage V2 of the power supply 800.

  In this case, the power supplies 600 and 800 are connected in series, and the test elements Z21, Z22, and Z23 form a parallel circuit through the bias elements Zr1, Zr2, and Zr3 in series with the series circuit of the power supplies 600 and 800, respectively. According to such a configuration, a current from the power supply 600 flows also to the power supply 800, and a current flows from the power supply 800 to the power supply 600.

Assuming i21, i22, and i23 as currents that the power source 600 passes through the test elements Z21, Z22, and Z23, respectively, the current i2n that the power source 600 passes through the test elements Z2n (n = 1, 2, 3) is
i2n = V1 / (Zr + Z2n) (6)
It becomes. If the impedance of the bias elements Zr1, Zr2, Zr3 is selected so that Zr >> Z2n,
i2n ≒ V1 ÷ Zr (7)
Since the impedances Zr of the bias elements Zr1, Zr2, and Zr3 are equal, i21≈i22≈i23.

  Further, since the frequency V2 of the power supply 800 is Zr << Z2n, it is almost equal to the case where the bias elements Zr1, Zr2, and Zr3 are short-circuited. Therefore, the voltage V2 of the power supply 800 is equally applied to the test elements Z21 to Z23.

[Tenth embodiment]

  Next, a tenth embodiment of the present invention will be described with reference to FIGS. FIG. 28 is a circuit diagram showing a ripple test apparatus according to the tenth embodiment, and FIG. 29 is a circuit diagram showing an equivalent circuit thereof.

  In this embodiment, in the fifth embodiment (FIG. 17), the capacitors C1 to C3 are configured by the element circuit 400 including the other elements Z1 to Z3, and the capacitors Cr1 to Cr3 are replaced with the other elements Za1 to Za3. The inductors L1 to L3 are replaced with other elements Zb1, Zb2, and Zb3, and power supplies 600 and 800 are used. That is, since the parallel circuit of the power supply 600 and the elements Za1, Za2, Za3, the power supply 800 and the elements Zb1, Zb2, and Zb3 can be replaced with the equivalent circuit shown in FIG. 29, the bias element is configured with the impedance Zo. From the viewpoint of the test elements Z1 to Z3, it can be seen that the circuit of FIG. 28 is equivalent to the circuit of FIG.

[Other modes of implementation]

  Next, other embodiments are listed as follows.

  (1) In the second embodiment (FIG. 11), the capacitors C1 to C6 may be replaced with, for example, elements Z1 to Z6 other than the capacitors as arbitrary elements to be tested.

  (2) In the third embodiment (FIG. 13), each of the capacitors C1 to C4 may be changed to an arbitrary element.

  (3) In the sixth embodiment (FIG. 22), the capacitors C1 to C6 may be replaced with arbitrary elements, and the power sources 6 and 81 to 83 may be replaced with an AC power source or a DC power source.

  (4) In the above embodiment (FIG. 16), the use of the DC voltage generated in the resistors R1 to R3 for taking out the leakage current is exemplified, but the ripple current can also be extracted by the AC voltage generated in the resistor. Further, in each embodiment, an output circuit such as a transformer may be installed for extracting the ripple current.

  (5) The leak current and ripple current taken out from the ripple test apparatus 2 can be used for testing the characteristics and deterioration state of elements such as capacitors, which are elements to be tested, in addition to an arithmetic unit (not shown).

(6) In addition, the present invention may change the waveform of the power source or replace the element under test with a capacitor, an arbitrary resistor or coil, and the present invention is not limited to the above embodiment. .

According to the present invention, it can be used for testing various elements such as capacitors, and the characteristics and durability of the elements can be known, thereby contributing to the improvement of the reliability of the elements.

It is a circuit diagram which shows an example of the ripple test apparatus which concerns on 1st Embodiment. It is a circuit diagram which shows an example of a test apparatus. It is a figure which shows a simulation result. It is a circuit diagram which shows the other structural example of the test apparatus in 1st Embodiment. It is a figure which shows a simulation result. It is a circuit diagram which shows the structural example of a bias element. It is a circuit diagram which shows the modification in 1st Embodiment. It is a circuit diagram which shows the modification in 1st Embodiment. It is a circuit diagram which shows the modification in 1st Embodiment. It is a circuit diagram which shows the modification in 1st Embodiment. It is a circuit diagram which shows an example of the ripple test apparatus which concerns on 2nd Embodiment. It is a figure which shows the equivalent circuit of a transformer. It is a circuit diagram which shows an example of the ripple test apparatus which concerns on 3rd Embodiment. It is a circuit diagram which shows an example of the ripple test apparatus which concerns on 4th Embodiment. It is a figure which shows the structural example of an impedance element. It is a circuit diagram which shows the structural example of the test apparatus which added the detection resistance of leak current. It is a circuit diagram which shows the ripple test apparatus which concerns on 5th Embodiment. It is a circuit diagram which shows a simulation circuit. It is a figure which shows a simulation result. It is a figure which shows a simulation result. It is a figure which shows a simulation result. It is a circuit diagram which shows an example of the ripple test apparatus which concerns on 6th Embodiment. It is a figure which shows the structural example of a bias element. It is a circuit diagram which shows the ripple test apparatus which concerns on 7th Embodiment. It is a circuit diagram which shows the ripple test apparatus which concerns on 8th Embodiment. It is a circuit diagram which shows the specific example of a test apparatus. It is a circuit diagram which shows the ripple test apparatus which concerns on 9th Embodiment. It is a circuit diagram which shows the ripple test apparatus which concerns on 10th Embodiment. It is a circuit diagram which shows the equivalent circuit of a test apparatus. It is a circuit diagram which shows the conventional ripple test apparatus.

Explanation of symbols

2 Ripple test equipment 4 Capacitor circuit C1, C2, C3, C4, C5, C6 Capacitor (device under test)
6 AC power supply (first power supply)
8 DC bias power supply (second power supply)
Z1, Z2, Z3, Z4, Z5 Bias element

Claims (11)

A device testing apparatus for supplying a ripple current to a device under test,
A first power supply for applying a ripple current to the element;
A second power supply for applying a bias voltage to the element;
A bias element that passes direct current and blocks alternating current;
The test apparatus is characterized in that the element is connected in series to the first power supply, and the element is connected in parallel to the second power supply via the bias element. A device testing apparatus for supplying a ripple current to a device under test,
A first power supply for applying a ripple current to the element;
A second power source for generating a DC voltage;
A biasing element provided between the second power source and the element to pass the DC voltage and block the ripple current;
And the device is provided with the ripple current from the first power supply and the DC voltage from the second power supply. A capacitor testing apparatus for causing a ripple current to flow through a capacitor of a device under test,
A test apparatus, wherein a ripple current is applied to the capacitor and a DC bias voltage is applied, and a bias element that passes the DC bias voltage and blocks the ripple current is connected to the capacitor. A capacitor testing apparatus for causing a ripple current to flow through a capacitor of a device under test,
A first power supply for applying a ripple current to the capacitor;
A second power source for generating a DC voltage;
A biasing element provided between the second power source and the capacitor for passing the DC voltage and blocking the ripple current;
And the capacitor is provided with the ripple current from the first power supply and the DC voltage from the second power supply. A capacitor testing apparatus for causing a ripple current to flow through a capacitor of a device under test,
A capacitor circuit composed of a plurality of capacitors;
A first power supply for applying a ripple current to the capacitor circuit or the capacitor;
A second power source for generating a DC voltage to be applied to the capacitor circuit or the capacitor;
The second power supply is interposed between the capacitor circuit or the capacitor, passes the DC voltage of the second power supply and applies the same to the capacitor circuit or the capacitor, and the first power supply A bias element for blocking ripple current;
And the bias element is composed of an inductor having a winding, and the inductor has a small inductance with respect to a current component having the same value as the capacitor, and a current component having a different value with respect to the capacitor. On the other hand, the test apparatus is connected to the capacitor so as to set an inductance large. The test apparatus according to claim 1, 2, 3, or 4,
The test apparatus according to claim 1, wherein the bias element has an impedance equal to or higher than an impedance value of the element. The test apparatus according to claim 1, 2, 3, or 4,
The test apparatus characterized in that the bias element is a diode. The test apparatus according to claim 1, 2, 3, 4 or 5,
A test apparatus for detecting a leak current of the element from a DC voltage generated in the bias element or a DC voltage generated in a resistor connected to the bias element. The test apparatus according to claim 1, 2, 3, 4 or 5,
A test apparatus for detecting a ripple current of the element from an AC voltage generated in the bias element or an AC voltage generated in a resistor connected to the bias element. The test apparatus according to claim 1, 2, 3, 4 or 5,
A test apparatus, wherein the bias element is a transformer. The test apparatus according to claim 1, 2, 3, 4 or 5,
The test apparatus according to claim 1, wherein the bias element is a resonance circuit or a resonance element that resonates at a frequency of the first power source.

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