JP2008304241A - Inverter module inspection device and inspection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inspect a switching element of an inverter module in a short time.
An inspection apparatus includes: a first DC power source that applies a DC voltage between positive and negative input terminals of an inverter module; U-phase, V-phase, and W-phase output terminals of the inverter module; A test voltage power source for applying periodically varying voltage with different phases between the input terminals, and a galvanometer for detecting currents flowing into the U-phase, V-phase, and W-phase output terminals of the inverter module. Is provided. The inspection voltage power source fluctuates the potential at each of the U-phase, V-phase, and W-phase output terminals of the inverter module in a range equal to or greater than the potential at the negative-side input terminal. The first DC power source maintains the potential at the input terminal on the positive electrode side of the inverter module to be equal to or higher than the potential at the output terminals of the U phase, V phase, and W phase of the inverter module.
[Selection] Figure 1

Description

  The present invention relates to a technique for inspecting an inverter module.

  There is known an inverter module that inputs a DC voltage from a DC power source such as a battery and outputs a three-phase AC voltage to a load such as a three-phase motor. In this type of inverter module, positive and negative input terminals connected to a DC power source and U-phase, V-phase, and W-phase output terminals connected to a load are connected via switching elements, respectively. Has been. The inverter module outputs three-phase AC voltages from the U-phase, V-phase, and W-phase output terminals by controlling on / off of these six switching elements over time.

From the above configuration, in the inverter module, each built-in switching element needs to have a sufficient off-breakdown voltage (maximum applied voltage capable of maintaining the off state), and an inspection for confirming the off-breakdown voltage of each switching element after manufacturing is performed. Has been done. In this test, a test voltage (a voltage equal to the required off breakdown voltage) is applied between one input terminal and one output terminal of the inverter module, and the leakage current flowing between both terminals is measured, The off breakdown voltage of the switching element inserted between the elements is confirmed.
All switching elements are checked for off breakdown voltage, and if there is no problem, an inverter module operation test or the like is performed next. For example, Patent Document 1 describes a technique related to an operation test of an inverter module.

JP 2006-194718 A

In the conventional inspection technique, a DC voltage is applied to the switching element as an inspection voltage in order to inspect the OFF breakdown voltage of the switching element. That is, a DC power supply is connected to one input terminal and one output terminal of the inverter module, a DC test voltage is applied to a switching element inserted between the two terminals, and a leak current generated at that time is measured. is doing. Therefore, a surge voltage may be generated at the start or end of application of the inspection voltage, and the switching element of the inverter module may be damaged. In addition, simultaneously applying inspection voltages to a plurality of switching elements and inspecting the plurality of switching elements at the same time may cause an excessive leakage current through the plurality of switching elements, thereby damaging the inspection apparatus. Sometimes. Therefore, it is necessary to individually inspect a plurality of switching elements, and there is a problem that the time required for the inspection becomes long.
The present invention solves the above problems. The present invention provides a technique capable of inspecting the OFF breakdown voltage of a plurality of switching elements built in an inverter module in a relatively short time without damaging the inverter module and the inspection device.

  The technology of the present invention is embodied in an inspection device that inspects an inverter module that inputs a DC voltage from positive and negative input terminals and outputs a three-phase AC voltage from U-phase, V-phase, and W-phase output terminals. Is done. The inspection apparatus includes a first DC power source that applies a DC voltage between the positive and negative input terminals of the inverter module, U-phase, V-phase, and W-phase output terminals of the inverter module, and a negative input terminal. Are provided with a test voltage power source for applying periodically varying test voltages at different phases, and a galvanometer for detecting currents flowing into the U-phase, V-phase, and W-phase output terminals of the inverter module. ing. The inspection voltage power source fluctuates a potential at each of the U-phase, V-phase, and W-phase output terminals of the inverter module in a range equal to or greater than a potential at the input terminal on the negative electrode side of the inverter module. The first DC power source maintains the potential at the input terminal on the positive electrode side of the inverter module to be equal to or higher than the potential at the output terminals of the U phase, V phase, and W phase of the inverter module.

This inspection apparatus periodically varies the inspection voltage applied to the switching element. Thereby, it is possible to suppress a surge voltage generated at the start or end of application of the inspection voltage.
This inspection device applies periodically varying inspection voltages between the U-phase output terminal and the negative-side input terminal of the inverter module, between the V-phase output terminal and the negative-side input terminal, Application is made in a different phase between the output terminal and the negative input terminal. And the electric current which flows into each output terminal of U phase, V phase, and W phase is detected, respectively. Accordingly, the switching element inserted between the U-phase output terminal and the negative input terminal, and the switching element inserted between the V-phase output terminal and the negative input terminal. The OFF breakdown voltage of the switching element inserted between the W-phase output terminal and the negative input terminal can be simultaneously tested. Since the inspection voltage applied to each switching element fluctuates in different phases, the maximum inspection voltage is not applied to multiple switching elements at the same time, preventing the occurrence of excessive leakage current through multiple switching elements. Is done.

At the time of the above inspection, this inspection apparatus varies the potential at the output terminals of the U-phase, V-phase, and W-phase of the inverter module within a range equal to or higher than the potential at the input terminal on the negative side of the inverter module. The potential at the input terminal on the positive electrode side is maintained to be equal to or higher than the potential at each output terminal of the U phase, V phase, and W phase of the inverter module. As a result, current other than the leakage current to be detected is prohibited from flowing through a diode or the like built in the inverter module.
According to this inspection apparatus, it is possible to inspect the OFF breakdown voltage of the plurality of switching elements built in the inverter module in a relatively short time without damaging the inverter module or the inspection apparatus.

In the inspection apparatus described above, the inspection voltage power source is configured using a three-phase four-wire AC power source and a second DC power source having a positive electrode connected to a neutral phase of the three-phase four-wire AC power source. be able to. In this case, the first phase, the second phase, and the third phase of the three-phase four-wire AC power source are connected to the U-phase, V-phase, and W-phase output terminals of the inverter module, respectively, and the negative electrode of the DC power source is connected. It may be connected to the input terminal on the negative side of the inverter module. The DC voltage output from the second DC power supply may be equal to or greater than the amplitude of the three-phase AC voltage output from the three-phase four-wire AC power supply.
According to this inspection voltage power supply, a three-phase inspection voltage generated by raising the three-phase AC voltage output from the three-phase four-wire AC power supply to a range of zero volts or more is generated, and the three-phase inspection voltage is generated by the inverter module. Each of the three switching elements can be applied.

Alternatively, the inspection voltage source can be configured by a switching power supply including a third DC power supply and a plurality of switching elements.
According to this inspection voltage source, the maximum value and cycle of the inspection voltage can be appropriately changed by turning on / off the plurality of switching elements over time.

In the inspection apparatus described above, it is preferable that the galvanometer holds the maximum value of the current detected for each of the U-phase, V-phase, and W-phase output terminals of the inverter module.
The leakage current generated in the switching element fluctuates following the inspection voltage applied to the switching element, and the leakage current becomes maximum when the inspection voltage becomes maximum. In order to correctly determine the OFF breakdown voltage of the switching element, it is necessary to detect the maximum value of this leakage current. If the galvanometer has a so-called peak hold function, the maximum value of the leak current can be detected without continuing to watch the galvanometer during the inspection period.

The technique of the present invention is also embodied in an inspection method for inspecting the inverter module described above. In this inspection method, a DC voltage is applied between the positive and negative input terminals of the inverter module, and a cycle is provided between the U-phase, V-phase, and W-phase output terminals of the inverter module and the negative input terminal. Voltage application step of applying the test voltage that fluctuates in different phases, and a current detection step of detecting the current flowing into each output terminal of the U phase, V phase, and W phase of the inverter module. In the voltage application step, the potential at each output terminal of the U-phase, V-phase, and W-phase of the inverter module is varied within a range equal to or higher than the potential at the input terminal on the negative side of the inverter module, and the positive side of the inverter module The potential at the input terminal is maintained to be equal to or higher than the potential at each output terminal of the U-phase, V-phase, and W-phase of the inverter module.
According to this inspection apparatus, it is possible to inspect the OFF breakdown voltage of the plurality of switching elements built in the inverter module in a relatively short time without damaging the inverter module or the inspection apparatus.

A second inspection device embodied by the present invention is an inverter module that inputs a DC voltage from positive and negative input terminals and outputs a three-phase AC voltage from U-phase, V-phase, and W-phase output terminals. A first DC power supply that applies a DC voltage between the positive and negative input terminals of the inverter module, and the positive input terminal of the inverter module and the U phase, V phase, and W phase. A test voltage power source that applies a periodically varying test voltage between the output terminals of the inverter modules in different phases, and a test that detects currents flowing from the U-phase, V-phase, and W-phase output terminals of the inverter module. Has a flow meter. The inspection voltage power source fluctuates the potential at each of the U-phase, V-phase, and W-phase output terminals of the inverter module within a range equal to or lower than the potential at the positive input terminal of the inverter module. The first DC power source maintains the potential at the input terminal on the negative side of the inverter module below the potential at the output terminals of the U phase, V phase, and W phase of the inverter module.
According to this inspection apparatus, the switching element is interposed between the positive-side input terminal and the U-phase output terminal, and between the positive-side input terminal and the V-phase output terminal. It is possible to simultaneously check the off breakdown voltage of the switching element and the off breakdown voltage of the switching element interposed between the positive-side input terminal and the W-phase output terminal.

In the second inspection method embodied by the present invention, a DC voltage is applied between the positive and negative input terminals of the inverter module, and the positive input terminal of the inverter module and the U phase, V phase, W A voltage application step of applying periodically varying inspection voltages between the output terminals of the phases in different phases, and currents that respectively detect currents flowing out from the U-phase, V-phase, and W-phase output terminals of the inverter module A detection step is provided. In the voltage application step, the potential at each output terminal of the U-phase, V-phase, and W-phase of the inverter module is varied within a range equal to or less than the potential at the input terminal on the positive side of the inverter module, and on the negative side of the inverter module. It is characterized in that the potential at the input terminal is maintained below the potential at each of the U-phase, V-phase, and W-phase output terminals of the inverter module.
According to this inspection apparatus, it is possible to inspect the OFF breakdown voltage of the plurality of switching elements built in the inverter module in a relatively short time without damaging the inverter module or the inspection apparatus.

  According to the present invention, an inverter module can be inspected safely and efficiently.

First, preferred embodiments for carrying out the present invention will be listed.
(Mode 1) The inspection device includes a first galvanometer inserted between the inspection voltage power supply and the U-phase output terminal of the inverter module, and between the inspection voltage power supply and the V-phase output terminal of the inverter module. A second galvanometer inserted, and a third galvanometer inserted between the inspection voltage power supply and the V-phase output terminal of the inverter module.
(Mode 2) Each of the first galvanometer, the second galvanometer, and the third galvanometer has a peak hold function that holds the maximum value of the detected current.
(Mode 3) Three-phase inspection voltages generated by the inspection voltage power supply have a phase difference of 120 degrees from each other.
(Mode 4) The three-phase test voltage generated by the test voltage power supply varies between zero volts and approximately 600 volts, and the DC voltage output from the first DC power supply is adjusted to approximately 620 volts.

Example 1
An inspection apparatus and inspection method for inspecting the inverter module 100 embodying the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of the inspection apparatus of this embodiment. The inspection apparatus according to the present embodiment inspects the off breakdown voltage of the plurality of switching elements 114, 115, and 116 built in the inverter module 100.

  Before describing the configuration of the inspection apparatus, the inverter module 100 that is the inspection target will be described. The inverter module 100 is an inverter module that inputs a DC voltage and outputs a three-phase AC voltage. The inverter module 100 includes a positive input terminal 101 and a negative input terminal 102 for inputting a DC voltage, a U-phase output terminal 131, a V-phase output terminal 132, and a W-phase output terminal 133 for outputting a three-phase AC voltage. When the inverter module 100 is used, the positive input terminal 101 is connected to the positive electrode of a DC power supply (for example, a battery), the negative input terminal 102 is connected to the negative electrode of the DC power supply, and a U-phase output terminal 131, the V-phase output terminal 132, and the W-phase output terminal 133 are connected to a load such as a three-phase motor.

  The inverter module 100 includes a first switching element 111 interposed between the positive electrode input terminal 101 and the U-phase output terminal 131, and a second switch element interposed between the positive electrode input terminal 101 and the V-phase output terminal 132. A switching element 112, a third switching element 113 interposed between the positive electrode input terminal 101 and the W-phase output terminal 133, and a fourth element interposed between the negative electrode input terminal 102 and the U-phase output terminal 131. A switching element 114, a fifth switching element 115 interposed between the negative electrode input terminal 102 and the V phase output terminal 132, and a sixth element interposed between the negative electrode input terminal 102 and the W phase output terminal 133. A switching element 116 is provided. Each switching element 111-116 is a semiconductor element, and more specifically, an insulated gate bipolar transistor (IGBT) element. The inverter module 100 includes diodes 121-126 connected in parallel to the switching elements 111-116.

  Next, the configuration of an inspection apparatus that inspects the inverter module 100 will be described. The inspection apparatus according to the present embodiment is used in the step of inspecting the off breakdown voltage of the switching elements 111 to 116 built in the inverter module 100. In particular, the fourth switching element 114, the fifth switching element 115, and the 6 is an inspection device for inspecting the OFF breakdown voltage of the switching element 116.

As shown in FIG. 1, the inspection apparatus includes a first DC power supply 20, an inspection voltage power supply 30, a first galvanometer 61, a second galvanometer 62, and a third galvanometer 63. .
The first DC power supply 20 has a positive electrode 21 connected to the positive input terminal 101 of the inverter module 100 and a negative electrode 22 connected to the negative input terminal 102 of the inverter module 100. As a result, the DC voltage output from the first DC power supply 20 is applied between the positive input terminal 101 and the negative input terminal 102 of the inverter module 100. The potential at the positive input terminal 101 is higher than the potential at the negative input terminal 102 by the value of the DC voltage output from the first DC power supply 20.
The inspection voltage power supply 30 includes a three-phase AC power supply 40 and a second DC power supply 50. The three-phase AC power supply 40 is a three-phase four-wire AC power supply, and includes a first phase terminal 41, a second phase terminal 42, a third phase terminal 43, and a neutral phase terminal 44. The first phase terminal 41 is connected to the U phase output terminal 131 of the inverter module 100, the second phase terminal 42 is connected to the V phase output terminal 132 of the inverter module 100, and the third phase terminal 43 is the W phase of the inverter module 100. Connected to the output terminal 133. Further, the neutral phase terminal 44 is connected to the positive electrode 51 of the second DC power supply 50. The negative electrode 52 of the second DC power supply 50 is connected to the negative input terminal 102 of the inverter module 100. Thereby, between the U-phase output terminal 131 and the negative input terminal 102 of the inverter module 100, between the V-phase output terminal 132 and the negative input terminal 102, and between the W-phase output terminal 133 and the negative input terminal 102, Three-phase fluctuating voltages obtained by biasing (raising) the three-phase AC voltage output from the three-phase AC power supply 40 by the DC voltage output from the second DC power supply 50 are applied.

  The first galvanometer 61 is inserted between the first phase terminal 41 of the three-phase AC power supply 40 and the U-phase output terminal 131 of the inverter module 100, and detects the current flowing into the U-phase output terminal 131. The second galvanometer 62 is interposed between the second phase terminal 42 of the three-phase AC power supply 40 and the V phase output terminal 132 of the inverter module 100, and detects a current flowing into the V phase output terminal 132. The third galvanometer 63 is interposed between the third phase terminal 43 of the three-phase AC power supply 40 and the W phase output terminal 133 of the inverter module 100, and detects a current flowing into the W phase output terminal 133. The first galvanometer 61, the second galvanometer 62, and the third galvanometer 63 have a peak hold function that holds the maximum value of the detected current.

Next, output voltages output from the first DC power supply 20, the three-phase AC power supply 40, and the second DC power supply 50 will be described.
First, the output voltage of the three-phase AC power supply 40 will be described. FIG. 2 shows the output voltage (when the neutral phase terminal 44 is grounded) output from the three-phase AC power supply 40 over time. As shown in FIG. 2, the three-phase AC power supply 40 outputs three-phase AC voltages U, V, and W that fluctuate with a phase difference of 120 degrees from each other. The amplitudes of the three-phase AC voltages U, V, and W output from the three-phase AC power source 40 may be set to approximately half of the required maximum inspection voltage. Here, the maximum inspection voltage is the maximum value of the inspection voltage to be applied to each switching element, and is a voltage equal to the off breakdown voltage required for each switching element. In this embodiment, since the maximum inspection voltage is set to 600 volts, the amplitudes of the three-phase AC voltages U, V, and W are set to 300 volts.
Next, the DC voltage output from the second DC power supply 50 may be set to be equal to or greater than the amplitude of the three-phase AC voltages U, V, and W output from the three-phase AC power supply 40. In the present embodiment, since the amplitude of the three-phase AC voltages U, V, and W is set to 300 volts, the DC voltage output from the second DC power supply 50 is set to 300 volts.
Finally, the DC voltage output from the first DC power supply 20 includes the amplitude of the DC voltage (300 volts) output from the first DC power supply 20 and the three-phase AC voltages U, V, and W output from the three-phase AC power supply 40. What is necessary is just to set more than the total value (600 volts) with (300 volts).

By setting the three-phase AC power source 40 that is the second DC power source 50, between the U-phase output terminal 131 and the negative input terminal 102 of the inverter module 100, the variable voltage V _U shown in FIG. 3 (a) is applied Is done. Thereby, the fourth switching element 114 inserted between the U-phase output terminal 131 and the negative input terminal 102, the variable voltage V _U is applied as a test voltage to inspect the off-state breakdown voltage. Between the V-phase output terminal 132 and the negative input terminal 102, variable voltage _{V V} shown in FIG. 3 (b) is applied. Thereby, the fluctuating voltage _VV is applied to the fifth switching element 115 inserted between the V-phase output terminal 132 and the negative input terminal 102 as an inspection voltage for inspecting the OFF breakdown voltage. Between the W-phase output terminal 133 and the negative input terminal 102, variable voltage _{V W} shown in FIG. 3 (c) is applied. Thereby, the sixth switching element 116 inserted between the W-phase output terminal 133 and the negative input terminal 102, the variable voltage V _W is applied as a test voltage to inspect the off-state breakdown voltage. The three-phase fluctuation voltages V _U , V _V , and V _W shown in FIGS. 3A to 3C have a minimum value of zero volts and a maximum value of 600 volts equal to the maximum inspection voltage. It fluctuates periodically with a phase difference.
Here, the three-phase fluctuation voltages V _U , V _V , and V _W shown in FIG. 3 respectively indicate the potentials of the U-phase, V-phase, and W-phase output terminals 131, 132, and 133 with respect to the negative input terminal 102. . As shown in FIG. 3, since the three-phase fluctuation voltages V _U , V _V , and V _W fluctuate in a range of zero volts or more, the potentials at the U-phase, V-phase, and W-phase output terminals 131, 132, and 133 are The voltage fluctuates in a range equal to or higher than the potential at the negative electrode input terminal 102.

If the switching elements 114, 115, 116 are applied with varying voltages V _U , V _V , V _W and the switching elements 114, 115, 116 have insufficient OFF breakdown voltage, the switching elements 114, 115, 116, In 116, a leak current is generated. For example, when a leak current is generated in the fourth switching element 114, a current flows from the test voltage power supply 30 to the U-phase output terminal 131, and a reaction appears in the first galvanometer 61. Similarly, when a leak current is generated in the fifth switching element 115, a reaction appears in the second galvanometer 62, and when a leak current is generated in the sixth switching element 116, a reaction appears in the third galvanometer 63. Here, the positive input terminal 101 of the inverter module is always maintained at a higher potential than the output terminals 131, 132, and 133 of the U phase, V phase, and W phase by the DC voltage (620 volts) from the first DC power supply 20. Is done. As a result, current is prohibited from flowing from the U-phase, V-phase, and W-phase output terminals 131, 132, and 133 to the positive electrode input terminal 101 through the diodes 121, 122, and 123. Therefore, the current value detected by each galvanometer 61, 62, 63 is substantially equal to the current value of the leak current generated by each switching element 114, 115, 116.

FIG. 4 shows an example of a change with time of leak currents I _U , I _V , and I _W detected by the galvanometers 61, 62, and 63. 4 (a) is the fifth switching indicates the leakage current I _U of the fourth switching element 114 which is detected by the first galvanometer 61, FIG. 4 (b) which is detected by the second galvanometer 62 shows the leakage current _{I V} of the device 115, FIG. 4 (c) shows the leakage current _{I W} of the sixth switching element 116 which is detected by the third galvanometer 63. As shown in FIGS. 4A to 4C, the leakage currents I _U , I _V , and I _W generated in the switching elements 114, 115, and 116 are the same as those shown in FIGS. 3A to 3C. It fluctuates in synchronization with the voltages (fluctuating voltages) V _U , V _V , and V _W and takes the maximum value when the inspection voltage becomes maximum. Off-state breakdown voltage of the switching elements 114, 115 and 116, determines based on the maximum value of the leakage current _{I U, I V, I W} . For example, if the maximum values of the leakage currents I _U , I _V , and I _W are less than or equal to a predetermined threshold, it can be determined that the switching elements 114, 115, and 116 have a sufficient off breakdown voltage. As described above, since each galvanometer 61, 62, 63 has a peak hold function, the maximum values of the detected leak currents I _U , I _V , I _W are held. The maximum values of the leakage currents I _U , I _V , and I _W can be detected without continuing to watch the galvanometers 61, 62, and 63 during the examination period.

As described above, according to the inspection apparatus of the present embodiment, a maximum inspection voltage of 600 volts is applied to each of the fourth switching element 114, the fifth switching element 115, and the sixth switching element 116 of the inverter module 100. The OFF breakdown voltage of the switching element 114, the fifth switching element 115, and the sixth switching element 116 can be inspected simultaneously.
In the inspection apparatus of the present embodiment, the inspection voltage applied to the fourth switching element 114, the fifth switching element 115, and the sixth switching element 116 is varied so as to draw a sine waveform over time. Thus, an excessive surge voltage is not generated at the start or end of application of the inspection voltage, and the inverter module is prevented from being damaged. Further, a high voltage such as 600 volts is not continuously applied to the switching elements 114, 115, and 116 whose off breakdown voltage is unknown. Thereby, even when the off breakdown voltage of each switching element 114, 115, 116 is insufficient, excessive leakage current is not continuously supplied, and the inspection apparatus is prevented from being damaged.

  In the inspection apparatus of the present embodiment, the inspection voltages applied to the fourth switching element 114, the fifth switching element 115, and the sixth switching element 116 are varied at different phases. Therefore, a high voltage such as 600 volts is not simultaneously applied to the three switching elements 114, 115, and 116. Even when the off breakdown voltage of the plurality of switching elements 114, 115, 116 is insufficient, it is possible to prevent an excessive leakage current from flowing through the inverter module 100 and the inspection apparatus.

  FIG. 5 shows a modification in which the configuration of the inspection voltage power supply 30 is changed in the inspection apparatus of the first embodiment. In the inspection apparatus shown in FIG. 5, the inspection voltage power supply 70 is configured using a third DC power supply 90 and a switching circuit 80 having a plurality of switching elements 81, 82, 83. A positive electrode 91 of the third DC power supply 90 is connected to output terminals 71, 72, and 73 via switching elements 81, 82, and 83, respectively. The negative electrode 92 of the third DC power supply 90 is connected to the negative input terminal 102 of the inverter module 100. The output terminals 71, 72, 73 of the inspection voltage power supply 70 are connected to the U-phase, V-phase, and W-phase output terminals 131, 132, 133 of the inverter module 100, respectively.

The output voltage of the third DC power supply 90 is 600 volts equal to the maximum inspection voltage. The plurality of switching elements 81, 82, and 83 are subjected to PWM control by a switching control circuit (not shown). That is, the inspection voltage power supply 70 is a so-called switching power supply, and by turning on / off the plurality of switching elements 81, 82, 83 over time, the three-phase fluctuation voltages V _U , V _U from their output terminals 71, 72, 73. _V, it is possible to output a _{V W.} The other configuration of the inspection apparatus shown in FIG. 5 is the same as that of the inspection apparatus shown in FIG. 1 described above.
Also with the inspection apparatus shown in FIG. 5, as with the inspection apparatus shown in FIG. 1, the off breakdown voltages of the plurality of switching elements 114, 115, 116 of the inverter module 100 can be measured simultaneously.

(Example 2)
FIG. 6 shows the configuration of the inspection apparatus according to the second embodiment. The inspection apparatus according to the present embodiment inspects the off-breakdown voltage of the first switching element 111, the second switching element 112, and the third switching element 113 built in the inverter module 100.
As shown in FIG. 6, the inspection apparatus according to the second embodiment includes a first DC power supply 20, an inspection voltage power supply 230, a first galvanometer 61, a second galvanometer 62, and a third galvanometer 63. It has. The inspection voltage power supply 230 includes a three-phase AC power supply 40 and a second DC power supply 50. The first DC power supply 20, the three-phase AC power supply 40, the second DC power supply 50, the first galvanometer 61, the second galvanometer 62, and the third galvanometer 63 are denoted by the same reference numerals in the first embodiment. Same as described. However, in the inspection voltage power supply 230 of the second embodiment, the negative electrode 52 of the second DC power supply 50 is connected to the neutral phase terminal 44 of the three-phase AC power supply 40.

In the inspection apparatus according to the second embodiment, the positive electrode 21 of the first DC power supply 20 is connected to the positive input terminal 101 of the inverter module 100 as in the inspection apparatus according to the first embodiment. The negative electrode 22 of the first DC power supply 20 is connected to the negative input terminal 102 of the inverter module 100. The first phase terminal 41 of the three-phase AC power supply 40 is connected to the U phase output terminal 131 of the inverter module 100 via the first galvanometer 61. The second phase terminal 42 of the three-phase AC power supply 40 is connected to the V phase output terminal 132 of the inverter module 100 via the second galvanometer 62. The third phase terminal 43 of the three-phase AC power supply 40 is connected to the W phase output terminal 133 of the inverter module 100 via the third galvanometer 63.
On the other hand, in the inspection device of the second embodiment, unlike the inspection device of the first embodiment, the positive electrode 51 of the second DC power supply 50 is connected to the positive input terminal 101 of the inverter module 100.

According to the inspection apparatus of the second embodiment, the potential at the positive input terminal 101 of the inverter module 100 is maintained at a higher potential by about 620 volts than the potential at the negative input terminal 102. Then, a variable voltage V _U shown in FIG. 7A is applied between the positive electrode input terminal 101 and the U-phase output terminal 131 of the inverter module 100. Thereby, the first switching element 111 interposed between the positive electrode input terminal 101 and the U-phase output terminal 131, the variable voltage V _U is applied as a test voltage to inspect the off-state breakdown voltage. Between the positive input terminal 101 and the V-phase output terminal 132, the variable voltage _{V V} shown in FIG. 7 (b) is applied. Thereby, the fluctuation voltage _VV is applied to the second switching element 112 inserted between the positive electrode input terminal 101 and the V-phase output terminal 132 as an inspection voltage for inspecting the OFF breakdown voltage. Between the positive input terminal 101 and the W-phase output terminal 133, the variable voltage _{V W} shown in FIG. 7 (c) is applied. Thereby, the third switching element 113 interposed between the positive electrode input terminal 101 and the W-phase output terminal 133, the variable voltage V _W is applied as a test voltage to inspect the off-state breakdown voltage. The three-phase fluctuation voltages V _U , V _V , and V _W shown in FIGS. 7A to 7C have a minimum value of zero volts and a maximum value of 600 volts that is equal to the maximum inspection voltage. It fluctuates periodically with a phase difference. At this time, the potentials at the U-phase, V-phase, and W-phase output terminals 131, 132, and 133 vary in the range of 20 volts to 620 volts, assuming that the potential at the negative input terminal 102 is zero volts. The potentials at the U-phase, V-phase, and W-phase output terminals 131, 132, and 133 vary within a range that is greater than or equal to the potential at the negative electrode input terminal 102 and less than or equal to the potential at the positive electrode input terminal 101.

If the switching elements 111, 112, 113 are applied with varying voltages V _U , V _V , V _W , and the switching elements 111, 112, 113 have insufficient OFF breakdown voltage, the switching elements 111, 112, In 113, a leak current is generated. For example, when a leak current is generated in the first switching element 111, a current flows from the U-phase output terminal 131 to the inspection voltage power supply 230, and a reaction appears in the first galvanometer 61. Similarly, when a leak current is generated in the second switching element 112, a reaction appears in the second galvanometer 62, and when a leak current is generated in the third switching element 113, a reaction appears in the third galvanometer 63. Here, the negative input terminal 102 of the inverter module is always maintained at a lower potential than the U, V, and W phase output terminals 131, 132, and 133. Therefore, it is prohibited that a current flows from the negative input terminal 102 to the U, V, and W phase output terminals 131, 132, and 133 through the diodes 124, 125, and 126. The current value detected by each of the galvanometers 61, 62, 63 is substantially equal to the current value of the leak current generated in each of the switching elements 111, 112, 113.

FIG. 8 shows an example of a change with time of leak currents I _U , I _V , and I _W detected by the galvanometers 61, 62, and 63. 8 (a) is a second switching shows the leakage current I _U of the first switching element 111 which is detected by the first galvanometer 61, FIG. 8 (b) is detected by the second galvanometer 62 shows the leakage current _{I V} of the device 112, FIG. 8 (c) shows the leakage current _{I W} of the third switching element 113 is detected by the third galvanometer 63. As shown in FIGS. 8A to 8C, the leakage currents I _U , I _V , and I _W generated in the switching elements 111, 112, and 113 are the same as those shown in FIGS. 7A to 7C. It fluctuates in synchronization with the voltages (fluctuating voltages) V _U , V _V , and V _W and takes the maximum value when the inspection voltage becomes maximum. The off breakdown voltage of each switching element 111, 112, 113 can be determined based on the maximum values of the leakage currents I _U , I _V , I _W. The maximum value of each leakage current I _U , I _V , I _W is held by the peak hold function of each galvanometer 61, 62, 63.

  As described above, according to the inspection apparatus of the present embodiment, a maximum inspection voltage of 600 volts is applied to each of the first switching element 111, the second switching element 112, and the third switching element 113 of the inverter module 100. The OFF breakdown voltage of the switching element 111, the second switching element 112, and the third switching element 113 can be inspected simultaneously.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

The figure which shows the structure of a test | inspection apparatus (Example 1). The figure which shows the three-phase alternating current voltage which a three-phase alternating current power supply outputs. The figure which shows the three-phase fluctuation voltage _VU , _VV , _VW which a test voltage power supply outputs (Example 1). FIG. 4 is a diagram illustrating leak currents I _U , I _V , and I _W to be detected (Example 1). The figure which shows the structure of the test | inspection apparatus (modification) using a switching power supply. The figure which shows the structure of an inspection apparatus (Example 2). The figure which shows the three-phase fluctuation voltage _VU , _VV , _VW which a test voltage power supply outputs (Example 2). FIG. 6 is a diagram illustrating a detected leakage current I _U , I _V , I _W (Example 2).

Explanation of symbols

20: First DC power supply 21: Positive electrode of the first DC power supply 22: Negative electrode 30 of the first DC power supply, 230: Inspection voltage power supply 40: Three-phase four-wire AC power supply 41: First of the three-phase four-wire AC power supply Phase terminal 42: Second phase terminal 43 of three-phase four-wire AC power source 43: Third phase terminal 44 of three-phase four-wire AC power source: Neutral phase terminal 50 of three-phase four-wire AC power source: Second DC power source 51: Positive electrode of second DC power supply 52: Negative electrodes 61, 62, 63 of second DC power supply: Galvanometer 100: Inverter module 101: Positive input terminal of inverter module 102: Negative input terminal of inverter module 111-116: Switching Element 121-126: Diode 131: U-phase output terminal 132 of inverter module: V-phase output terminal 133 of inverter module: W-phase output terminal of inverter module

Claims (7)

An inspection device for inspecting an inverter module that inputs a DC voltage from positive and negative input terminals and outputs a three-phase AC voltage from U-phase, V-phase, and W-phase output terminals,
A first DC power supply for applying a DC voltage between the positive and negative input terminals of the inverter module;
A test voltage power supply for applying periodically varying test voltages in different phases between the U-phase, V-phase, and W-phase output terminals of the inverter module and the input terminal on the negative electrode side;
Provided with galvanometers that respectively detect the current flowing into the U-phase, V-phase, and W-phase output terminals of the inverter module,
The inspection voltage power source varies the potential at each output terminal of the U-phase, V-phase, and W-phase of the inverter module in a range equal to or greater than the potential at the input terminal on the negative side of the inverter module,
The first DC power supply maintains the potential at the input terminal on the positive electrode side of the inverter module at or above the potential at the output terminals of the U phase, V phase, and W phase of the inverter module. The inspection voltage power source includes a three-phase four-wire AC power source and a second DC power source having a positive electrode connected to a neutral phase of the three-phase four-wire AC power source,
The first phase, the second phase, and the third phase of the three-phase four-wire AC power supply are connected to the U-phase, V-phase, and W-phase output terminals of the inverter module, respectively.
The negative electrode of the DC power supply is connected to the input terminal on the negative electrode side of the inverter module,
2. The inspection apparatus according to claim 1, wherein the second DC power supply outputs a DC voltage that is greater than or equal to an amplitude of a three-phase AC voltage output from the three-phase four-wire AC power supply.   2. The inspection voltage source is a switching power source including a third DC power source and a plurality of switching elements, and outputs the inspection voltage by turning on / off the plurality of switching elements over time. The inspection device described in 1.   4. The inspection device according to claim 1, wherein the galvanometer holds a maximum value of a current detected for each of output terminals of a U phase, a V phase, and a W phase of the inverter module. 5. . An inspection method for inspecting an inverter module that inputs a DC voltage from positive and negative input terminals and outputs a three-phase AC voltage from U-phase, V-phase, and W-phase output terminals,
A test in which a DC voltage is applied between the positive and negative input terminals of the inverter module and periodically varies between the U-phase, V-phase, and W-phase output terminals of the inverter module and the negative input terminal. A voltage applying step of applying voltages in different phases;
A current detection step of detecting current flowing into each output terminal of the U-phase, V-phase, and W-phase of the inverter module;
In the voltage application step, the potential at each of the U-phase, V-phase, and W-phase output terminals of the inverter module is changed within a range equal to or greater than the potential at the input terminal on the negative electrode side of the inverter module, and the input terminal on the positive electrode side of the inverter module The inspection method is characterized in that the potential at is maintained at or above the potential at the output terminals of the U phase, V phase, and W phase of the inverter module. An inspection device for inspecting an inverter module that inputs a DC voltage from positive and negative input terminals and outputs a three-phase AC voltage from U-phase, V-phase, and W-phase output terminals,
A first DC power supply for applying a DC voltage between the positive and negative input terminals of the inverter module;
A test voltage power supply for applying periodically varying test voltages in different phases between the input terminal on the positive electrode side of the inverter module and the output terminals of the U phase, V phase, and W phase;
Provided with galvanometers that detect currents flowing out from the U-phase, V-phase, and W-phase output terminals of the inverter module,
The inspection voltage power supply varies the potential at each output terminal of the U-phase, V-phase, and W-phase of the inverter module within a range equal to or lower than the potential at the input terminal on the positive side of the inverter module;
The first DC power supply maintains the potential at the negative input terminal of the inverter module below the potential at the U-phase, V-phase, and W-phase output terminals of the inverter module. An inspection method for inspecting an inverter module that inputs a DC voltage from positive and negative input terminals and outputs a three-phase AC voltage from U-phase, V-phase, and W-phase output terminals,
A test in which a DC voltage is applied between the positive and negative input terminals of the inverter module, and periodically varies between the negative input terminal of the inverter module and the U-phase, V-phase, and W-phase output terminals. A voltage applying step of applying voltages in different phases;
A current detection step of detecting current flowing out from each of the U-phase, V-phase, and W-phase output terminals of the inverter module;
In the voltage application step, the potential at each of the U-phase, V-phase, and W-phase output terminals of the inverter module is varied within a range equal to or less than the potential at the positive input terminal of the inverter module, and the negative input terminal of the inverter module An inspection method is characterized in that the potential at is maintained below the potential at each output terminal of the U phase, V phase, and W phase of the inverter module.

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