Test and / or measurement system and test and / or measurement procedure

Abstract

A test and / or measurement system, which is electrically connected to at least one arrangement of power electronic components having at least three parallel branches (1, 2, 3), each having a common branch positive terminal (4) and a common branch negative terminal (5), wherein each of the branches (1, 2, 3) has at least one first and at least one second power semiconductor (M1, M2; M3, M4; M5, M6), between each of which a center tap (11, 12, 13) is arranged, characterized in that the test and / or measurement system has a load current source (6) which is connected on one side to the branch positive terminal (4) and on the other side to the branch negative terminal (5);- in each of the branches (1, 2, 3) a branch selector switch (S1, S3, S5) is connected between the branch positive terminal (4) and the at least one first power semiconductor (M1, M3, M5) and a branch selector switch (S2, S4, S6) is connected between the branch negative terminal (5) and the at least one second power semiconductor (M2, M4, M6); - a branch changeover switch (AC_1, AC_2, AC_3) is connected between the center taps (11, 12, 13) of the branches (1, 2, 3);- in parallel to each power semiconductor (M1, M2, M3, M4, M5, M6) a bridging switch (P1, P2, P3, P4, P5, P6) is connected on one side directly or via one of the branch selector switches (S1, S2, S3, S4, S5, S6) to the branch positive terminal (4) or the branch negative terminal (5) and on the other side to the center tap (11, 12, 13) of the respective branch (1, 2, 3) or in parallel to a series circuit of each power semiconductor (M1, M2, M3, M4, M5, M6) and the respective associated branch selector switch (S1, S2, S3, S4, S5, S6) a bridging switch (P1, P2, P3, P4, P5, P6) is connected on one side directly or via one of the branch selector switches (S1, S2, S3, S4, S5, S6) to the branch positive terminal (4) or the branch negative terminal (5) and on the other side to the center tap (11, 12, 13) of the respective branch (1, 2, 3) 2, 3) connected bridging switch (P1, P2, P3, P4, P5, P6) is switched;- a measuring current source (I_sense) is connected or connectable to each of the power semiconductors (M1, M2, M3, M4, M5, M6) via at least one measuring switch (T);and - a voltage measuring device is connected or switchable in parallel to several or all of the power semiconductors (M1, M2, M3, M4, M5, M6).

Description

[0001] The present invention relates to a test and / or measurement system that is electrically connected to at least one arrangement of power electronic components comprising at least three parallel branches, each of which has a common positive branch pole and a common negative branch pole, wherein each of the branches comprises at least one first and at least one second power semiconductor, between which a center tap is arranged. The invention further relates to a test and / or measurement method for such a test and / or measurement system.

[0002] The arrangement of power electronic components having at least three phases can, for example, be a B6 bridge circuit.

[0003] From the publication DE 10 2021 210 336 A1, a power module of an inverter with a B6 bridge circuit for supplying a three-phase electrical machine, in particular in a motor vehicle, is known. The B6 bridge circuit has three half-bridges connected in parallel. Each half-bridge comprises a series connection of two switching elements in the form of power semiconductors and is connected between the input terminals of the inverter. A center tap between each switching element is electrically connected to a phase terminal for connection to the three-phase electrical machine. The switching elements are controlled by a gate driver ASIC. By closing one of the upper or lower switching elements of a half-bridge, an electrical connection is established between an upper or lower DC voltage potential and a phase terminal.

[0004] For load tests on an arrangement of power electronic components in a B6 configuration, the power electronic components of the arrangement were previously energized individually as standard. This means that when load tests were performed on a B6 bridge circuit, only one power electronic component, such as an IGBT (insulated gate bipolar transistor) or one diode per branch, was energized in each branch of the B6 bridge circuit during the test. However, when using a B6 bridge circuit or another arrangement of power electronic components that has at least three parallel branches, several of the power electronic components in this arrangement, such as the IGBTs and the diodes of a branch, are heated simultaneously and subjected to the associated alternating thermo-mechanical loads.In previous tests, the temperature gradients encountered during the test and the associated component loads could therefore deviate from the component loads expected during converter operation of the arrangement. This could potentially lead to an underestimation or overestimation of the service life of the respective power electronic components or the entire arrangement.

[0005] Measurements of the thermal impedance Z have also been very complex. th on arrangements of power electronic components that have at least three parallel branches, such as B6 bridge circuits. For such measurements, it was previously necessary to manually contact and measure individual power electronic components or combinations thereof.

[0006] The points listed above have led to the fact that the complete characterization of a module comprising at least three parallel branches or phases and comprising power electronic components at various parameters, such as coolant volume flow, coolant temperature and / or load current, has previously required approximately two weeks of work.

[0007] It is the object of the present invention to provide a test and / or measurement system and a test and / or measurement method which enable an application-oriented simulation of electrical and / or thermal loads on an arrangement of power electronic components in a B6 configuration with relatively little test and / or measurement time expenditure.

[0008] The object is achieved, on the one hand, by a test and / or measuring system which is electrically connected to at least one arrangement of power electronic components which has at least three parallel branches, each of which has a common branch positive pole and a common branch negative pole, wherein each of the branches has at least one first and at least one second power semiconductor, between which a center tap is arranged, wherein - the test and / or measurement system comprises a load current source connected on the one hand to the positive branch pole and on the other hand to the negative branch pole; - in each of the branches, a branch selector switch is connected between the branch positive pole and the at least one first power semiconductor, and a branch selector switch is connected between the branch negative pole and the at least one second power semiconductor; - a branch changeover switch is connected between the center taps of each branch; - a bypass switch is connected in parallel to the respective power semiconductor, which is connected on the one hand directly or via one of the branch selector switches to the branch positive pole or the branch negative pole and on the other hand to the center tap of the respective branch, or a bypass switch is connected in parallel to a series circuit comprising the respective power semiconductor and the respective associated branch selector switch, which is connected on the one hand to the branch positive pole or the branch negative pole and on the other hand to the center tap of the respective branch; - a measuring current source is connected or connectable to each of the power semiconductors via at least one measuring switch; and - a voltage measuring device is connected or can be connected in parallel to several or all of the power semiconductors.

[0009] The test and / or measurement system according to the invention serves for the metrological characterization and / or the performance of load tests on individual or all of the power semiconductors in the arrangement. Each of the power semiconductors can be energized by appropriately conducting a load current provided by the load current source using appropriate switch positions of the branch selector load switches and the branch alternating load switches, and then a measurement voltage can be recorded across the respective power semiconductor.

[0010] In addition, the corresponding power semiconductor can be supplied with load current by setting the measuring switches accordingly. The respective switch positions can be changed very quickly, and any combination of power semiconductor currents can be set. Thus, by switching the switches of the test and / or measurement system on or off, one or more of the power semiconductors in the array can be supplied with the load current in series. This allows realistic operation of the power semiconductors in the array to be simulated, thus capturing a more application-oriented stress on the power semiconductors.

[0011] The test and / or measuring system according to the invention enables not only the measurement on a power semiconductor supplied with load current, but also its influence, caused by the thermal coupling, on the other power semiconductors of the arrangement which are not supplied with current or are supplied with current at a different time.

[0012] The test and / or measuring system according to the invention has the great advantage that in particular the thermal characterization of the power semiconductors of the arrangement in B6 configuration, i.e. in particular their thermal impedance, can be recorded automatically.

[0013] When the power semiconductors are supplied with the load current provided by the load current source, they heat up. Once the respective power semiconductor is no longer supplied with the load current, a cooling curve is measured on the respective power semiconductor using the test and / or measurement system according to the invention. For this purpose, the respective power semiconductor is supplied with a measuring current from a measuring current source during off-load operation that is significantly lower than the load current. The thermal impedance represents the power loss of the respective power semiconductor.

[0014] The test and / or measurement system according to the invention significantly reduces the measurement time required for the system compared to the previously common manual individual measurements. On the one hand, this reduces the costs for characterizing individual power semiconductors or test objects in the system. On the other hand, it makes it possible to provide a larger number of measurements on power semiconductors or test objects, for example, during a circuit development phase, thus allowing potential quality variations to be evaluated.

[0015] The test and / or measurement system according to the invention also makes it possible to adapt the stress on the power semiconductors or test objects during load cycling tests more closely to the field conditions. This allows for more accurate measurement results and the detection of potential failure mechanisms that were not visible in previous standard measurement methods.

[0016] In an advantageous embodiment of the test and / or measuring system according to the invention, a load current source positive pole of the load current source is connected or connectable to the branch positive pole via a first current direction selector load switch and to the branch negative pole via a second current direction selector load switch, and a load current source negative pole of the load current source is connected or connectable to the branch positive pole via a third current direction selector load switch and to the branch negative pole via a fourth current direction selector load switch.

[0017] This allows different current directions of the load current through the branches to be set from a single load current source. The current direction selector switches can be used to reverse the current flow in each case. Otherwise, a second load current source would be required for comprehensive electrical characterization and / or a comprehensive stress test on the power semiconductors in the arrangement, which would be significantly more expensive than the four current direction selector switches.

[0018] The respective power semiconductors can be connected to the measuring current source in that a series arrangement comprising the at least one measuring switch and the measuring current source is connected in parallel to the respective power semiconductor.

[0019] However, it is also possible to establish electrical connections between the respective power semiconductors and the respectively associated measuring current source in that the at least one measuring switch comprises at least four measuring switches, wherein a measuring current source positive pole of the measuring current source is connected or connectable via a first of the at least four measuring switches to a first terminal of the power semiconductor and via a second of the at least four measuring switches to a second terminal of the power semiconductor, and a measuring current source negative pole is connected or connectable via a third of the at least four measuring switches to the first terminal of the power semiconductor and via a fourth of the at least four measuring switches to the second terminal of the power semiconductor.

[0020] The object is further achieved by a test and / or measuring method carried out on an embodiment of the test and / or measuring system according to the invention, in which - individual or both of the at least one first power semiconductor and the at least one second power semiconductor are alternately supplied with current by means of the load current source from one or two branches of the arrangement of power electronic components, by switching individual ones of the current direction selector load switches and / or the branch selector load switches and / or the bypass switches in different configurations; - at least one of the power semiconductors not supplied with current by the load current source is connected to the measuring current source connected in series with this measuring switch by switching the measuring switch connected in parallel to this power semiconductor and is thereby supplied with a measuring current; and - at least one measuring voltage is measured by the voltage measuring device connected in parallel to the respective power semiconductor.

[0021] In an advantageous embodiment of the test and / or measurement method according to the invention, a positive pole of the load current source is connected to the positive branch pole via a first current direction selector switch or to the negative branch pole via a second current direction selector switch, and a negative pole of the load current source is connected to the positive branch pole via a third current direction selector switch or to the negative branch pole via a fourth current direction selector switch. As a result, the branches of the arrangement are energized in different current directions by the load current source, allowing very rapid current direction changes. Accordingly, the electrical and / or thermal parameters of the power semiconductors can be recorded during rapidly changing current directions.

[0022] Advantageous embodiments of the test and / or measuring system according to the invention and advantageous embodiments of the test and / or measuring method according to the invention carried out thereon are explained in more detail below with reference to figures, wherein Fig. 1 schematically shows an embodiment of the test and / or measuring system according to the invention, which is electrically connected to an arrangement of power electronic components to be tested or measured; Fig. 2 schematically shows a diagram of the representation in Fig. 1 alternative wiring of bypass switches of the arrangement directly to a common two-positive pole or branch-negative pole; Fig. 3 schematically shows connections of measuring current sources of the test and / or measuring system to power semiconductors of the arrangement; Fig. 4 schematically shows a connection of a measuring current source via four measuring switches bidirectionally for each power semiconductor; the Fig. 5 to 7 show exemplary current flows of the arrangement in the forward direction in chronological sequence during a load change test by means of the test and / or measuring system according to the invention; the Fig. 8 to 10 show, by way of example, current flows of the arrangement in the reverse direction in chronological sequence during a load change test by means of the test and / or measuring system according to the invention; and the Fig. 11 to 13 show examples of current flows of individual power semiconductors in the forward direction.

[0023] Fig. Figure 1 schematically shows, using an exemplary embodiment, the structure and function of the test and / or measurement system according to the invention, which is electrically connected to an arrangement of power electronic components to be tested or measured. In the exemplary embodiment shown, this arrangement is a B6 bridge circuit, but in other embodiments, it can also comprise multiple B6 bridge circuits. The B6 bridge circuit shown is typically installed in the drives of electric vehicles or in solar inverters.

[0024] The Fig. The arrangement shown in Figure 1, which is to be tested or measured using the test and / or measurement system, has three electrically parallel branches 1, 2, 3. Branches 1, 2, 3 can also be referred to as phases.

[0025] The first branch 1 has two power semiconductors M1, M2, between which a center tap 11 is formed. The second branch 2 has two power semiconductors M3, M4, between which a center tap 12 is formed. The third branch 3 has two power semiconductors M5, M6, between which a center tap 13 is formed. The center taps 11, 12, 13 can also be referred to as AC taps, to which a top-side switch, i.e., the power semiconductor M1, M3, or M5, is connected on the one hand, and a bottom-side switch, i.e., the power semiconductor M2, M4, or M6, on the other hand.

[0026] In the embodiment shown, the power semiconductors M1, M2, M3, M4, M5, M6 are MISFETs, such as MOSFETs, but can also be bipolar transistors and / or IGBTs and / or power diodes and / or thyristors and / or triacs and / or HEMTs and / or other power semiconductors or combinations thereof.

[0027] The branches 1, 2, 3 have a common branch positive pole 4, which is the pole of the arrangement connected to DC+, also called the top connection, and a common branch negative pole 5, which is the pole of the arrangement connected to DC-, also called the bottom connection. In the first branch 1, a first power semiconductor M1 is located between the branch positive pole 4 and the center tap 11, and a second power semiconductor M2 is located between the center tap 11 and the branch negative pole 5. In the second branch 2, a first power semiconductor M3 is located between the branch positive pole 4 and the center tap 12, and a second power semiconductor M4 is located between the center tap 12 and the branch negative pole 5. In the third branch 3, a first power semiconductor M5 is located between the branch positive pole 4 and the center tap 13, and a second power semiconductor M6 is located between the center tap 13 and the branch negative pole 5.

[0028] In the first branch 1, a branch selector switch S1 is connected between the branch positive pole 4 and the first power semiconductor M1, and a branch selector switch S2 is connected between the second power semiconductor M2 and the branch negative pole 5. In the second branch 2, a branch selector switch S3 is connected between the branch positive pole 4 and the first power semiconductor M3, and a branch selector switch S4 is connected between the second power semiconductor M4 and the branch negative pole 5. In the third branch 3, a branch selector switch S5 is connected between the branch positive pole 4 and the first power semiconductor M5, and a branch selector switch S6 is connected between the second power semiconductor M6 and the branch negative pole 5.

[0029] A branch changeover switch AC_1 is connected between the center tap 11 of the first branch 1 and the center tap 12 of the second branch 2. A branch changeover switch AC_2 is connected between the center tap 12 of the second branch 2 and the center tap 13 of the third branch 3. A branch changeover switch AC_3 is connected between the center tap 13 of the third branch 3 and the center tap 11 of the first branch 1.

[0030] The branch selector switches S1, S2, S3, S4, S5, S6 and the branch alternating load switches AC_1, AC_2, AC_3 are used to select the power semiconductors M1, M2, M3, M4, M5, M6 to be energized.

[0031] In the first branch 1, a bypass switch P1 is connected in parallel with the first power semiconductor M1, and a bypass switch P2 is connected in parallel with the second power semiconductor M2. In the second branch 2, a bypass switch P3 is connected in parallel with the first power semiconductor M3, and a bypass switch P4 is connected in parallel with the second power semiconductor M4. In the third branch 3, a bypass switch P5 is connected in parallel with the first power semiconductor M5, and a bypass switch P6 is connected in parallel with the second power semiconductor M6.

[0032] As shown schematically in Fig. 2 using the first branch 1 of the arrangement of Fig. 1, alternatively, the bypass switch P1 can also be connected in parallel to the series circuit comprising the first power semiconductor M1 of the first branch 1 and the branch selector switch S1, the bypass switch P2 can be connected in parallel to the series circuit comprising the second power semiconductor M1 of the first branch 1 and the branch selector switch S2, the bypass switch P3 can be connected in parallel to the series circuit comprising the first power semiconductor M3 of the second branch 2 and the branch selector switch S3, the bypass switch P4 can be connected in parallel to the series circuit comprising the second power semiconductor M4 of the second branch 2 and the branch selector switch S4, the bypass switch P5 can be connected in parallel to the series circuit comprising the first power semiconductor M5 of the third branch 3 and the branch selector switch S5 and / or the bypass switch P6 can be connected in parallel to the series circuit comprising the second power semiconductor M6 of the third branch 3 and the branch selector switch S6.

[0033] The branch selector switches S1, S2, S3, S4, S5, S6, the branch alternating switches AC_1, AC_2, AC_3 and the bypass switches P1, P2, P3, P4, P5, P6 are components of the test and / or measuring system.

[0034] The test and / or measurement system further comprises a load current source 6. In the embodiment shown, the load current source 6 is a regulated current source, but it may also be unregulated. For example, the load current source 6 can be regulated in a range of 10 to 1200 A at a load voltage of 20 V. Preferably, the load current source 6 is always energized during a test and / or measurement process using the test and / or measurement system.

[0035] In the optional embodiment of the invention shown, a load current source positive pole 61 of the load current source 6 is connected either via a first current direction selection switch Q_SW1 to the branch positive pole 4 or via a second current direction selection switch Q_SW2 to the branch negative pole 5. Furthermore, in the embodiment shown, a load current source negative pole 62 of the load current source 6 is connected via a third current direction selection switch Q_SW3 to the branch positive pole 4 and via a fourth current direction selection switch Q_SW4 to the branch negative pole 5. The current direction selection switches Q_SW1, Q_SW2, Q_SW3, Q_SW4 serve to select the current direction of the load current through the power semiconductors M1, M2, M3, M4, M5, M6 to be tested and / or measured. The current direction selection load switches Q_SW1, Q_SW2, Q_SW3, Q_SW4 are designed as power semiconductors in the embodiment shown.

[0036] The current direction selector switches Q_SW1, Q_SW2, Q_SW3, Q_SW4 are optional components of the test and / or measurement system.

[0037] The test and / or measurement system further comprises a measuring current source I_sense in parallel with each of the power semiconductors M1, M2, M3, M4, M5, M6, whereby the measuring current sources I_sense are shown in Fig. 1 are not shown. Examples of measuring current sources I_sense1 and I_sense2 that supply the respective power semiconductor with measuring current are shown in Fig. 3 or a bidirectional measuring current source I_sense3 supplying the respective power semiconductor with measuring current in Fig. 4 shown.

[0038] A measuring switch T is connected between the respective power semiconductors M1, M2, M3, M4, M5, M6 and the respective measuring current source I_sense, as shown by way of example in Figure 1 using the measuring switches T1, T2. Fig. 3. The measuring switches T are used to switch a measuring current through the power semiconductors M1, M2, M3, M4, M5, M6 to be tested or measured. To measure or test the power semiconductors M1, M2, M3, M4, M5, M6 using the measuring current, these are switched off in the present arrangement, where the power semiconductors M1, M2, M3, M4, M5, M6 are MISFETS. The power semiconductors M1, M2, M3, M4, M5, M6 can be measured in any order.

[0039] Instead of the Fig. 3, the respective measuring current source I_sense can also be connected or connectable bidirectionally to the respective power semiconductor M1, M2, M3, M4, M5, M6, as shown schematically in Fig. 4. In this case, instead of the one shown in Fig. 3 used measuring switch T, at least four measuring switches T3, T4, T5, T6 are provided, wherein a measuring current source positive pole of the measuring current source I_sense is connected or connectable via a first of the at least four measuring switches T3, T4, T5, T6 to a first terminal of the respective power semiconductor M1, M2, M3, M4, M5, M6 and via a second of the at least four measuring switches T3, T4, T5, T6 to a second terminal of the respective power semiconductor M1, M2, M3, M4, M5, M6, and a measuring current source negative pole of the measuring current source I_sense is connected via a third of the at least four measuring switches T3, T4, T5, T6 to the first terminal of the respective power semiconductor M1, M2, M3, M4, M5, M6 and via a fourth of the at least four measuring switches T3, T4, T5, T6 to the second terminal of the respective power semiconductor M1, M2, M3, M4, M5, M6 is connected or connectable.

[0040] In addition, in the test and / or measuring system, a voltage measuring device is connected or can be connected in parallel to several or all of the power semiconductors M1, M2, M3, M4, M5, M6, which Fig. 1 is not shown for the sake of clarity.

[0041] In principle, any combination of currents supplied to the arrangement is possible with the aid of the test and / or measuring system according to the invention within a load change test.

[0042] The Fig. Figures 5 to 7 show exemplary current flows of the arrangement in the forward direction, similar to the application in converter operation, in chronological sequence during a load change test using the test and / or measurement system according to the invention. The load current curve is shown schematically in each case using a thick dotted line.

[0043] In the Fig. In the first current supply step of the load change test in the forward direction, which is schematically illustrated in Figure 5, the load current flows from the load current source positive pole 61 of the load current source 6, first via the closed current direction selection switch Q_SW1 to the branch positive pole 4. From there, the load current flows via the closed branch selection switch S1 to supply current to the first power semiconductor M1 of the first branch 1. The load current then branches off at the center tap 11 of the first branch 1 and flows via the closed branch changeover switch AC_1 to the center tap 12 of the second branch 2. From there, the load current energizes the second power semiconductor M4 of the second branch 2 and then flows via the closed branch selection switch S4 to the branch negative pole 5 and from there via the closed current direction selection switch Q_SW4 to the load current source negative pole 62 of the load current source 6.Except for the aforementioned closed switches Q_SW1, S1, AC_1, S4, Q_SW4, all other load switches of the test and / or measurement system are open during the first current supply step.

[0044] In the Fig. 6, the load current flows from the load current source positive pole 61 of the load current source 6, first via the closed current direction selector switch Q_SW1 to the branch positive pole 4. From there, the load current flows via the closed branch selector switch S3 to energize the first power semiconductor M3 of the second branch 2. The load current then branches off at the center tap 12 of the second branch 2 and flows via the closed branch selector switch AC_2 to the center tap 13 of the third branch 3. From there, the load current energizes the second power semiconductor M6 of the third branch 3 and then flows via the closed branch selector switch S6 to the branch negative pole 5 and from there via the closed current direction selector switch Q_SW4 to the load current source negative pole 62 of the load current source 6.Except for the aforementioned closed switches Q_SW1, S3, AC_2, S6, Q_SW4, all other load switches of the test and / or measurement system are open during the second current supply step in the forward direction.

[0045] In the Fig. In the third current supply step of the load change test in the forward direction, schematically illustrated in Figure 7, the load current flows from the load current source positive pole 61 of the load current source 6, first via the closed current direction selection switch Q_SW1 to the branch positive pole 4. From there, the load current flows via the closed branch selection switch S5 to energize the first power semiconductor M5 of the second branch 3. The load current then branches off at the center tap 13 of the third branch 3 and flows via the closed branch changeover switch AC_3 to the center tap 11 of the first branch 1. From there, the load current energizes the second power semiconductor M2 of the first branch 1 and then flows via the closed branch selection switch S2 to the branch negative pole 5 and from there via the closed current direction selection switch Q_SW4 to the load current source negative pole 62 of the load current source 6.Except for the aforementioned closed switches Q_SW1, S5, AC_3, S2, Q_SW4, all other load switches of the test and / or measurement system are open during the third current supply step in the forward direction.

[0046] In the forward direction, a wide variety of current flow variations for the individual power semiconductors M1, M2; M3, M4; M5, and M6 are possible. For example, it is also conceivable to supply current to power semiconductors M1 and M6 in the first current flow step, to power semiconductors M3 and M2 in the second current flow step, and to power semiconductors M5 and M4 in the third current flow step in the forward direction.

[0047] The Fig. Figures 8 to 10 show examples of reverse current flow through the arrangement, similar to the application in converter operation, in chronological order during a load change test using the test and / or measurement system according to the invention. The load current curve is shown schematically in each case using a thick dotted line.

[0048] In the Fig. In the first current supply step of the load change test in the reverse direction, schematically illustrated in Figure 8, the load current flows from the load current source positive pole 61 of the load current source 6, first via the closed current direction selection switch Q_SW2 to the branch negative pole 5. From there, the load current flows via the closed branch selector switch S4 to supply current to the second power semiconductor M4 of the second branch 2. The load current then branches off at the center tap 12 of the second branch 2 and flows via the closed branch changeover switch AC_1 to the center tap 11 of the first branch 1. From there, the load current energizes the first power semiconductor M1 of the first branch 1 and then flows via the closed branch selector switch S1 to the branch positive pole 4 and from there via the closed current direction selection switch Q_SW3 to the load current source negative pole 62 of the load current source 6.Except for the aforementioned closed switches Q_SW2, S4, AC_1, S1, Q_SW3, all other load switches of the test and / or measurement system are open during the first current supply step in the reverse direction.

[0049] In the Fig. In the second current supply step of the load change test in the reverse direction, schematically illustrated in Figure 9, the load current flows from the load current source positive pole 61 of the load current source 6, first via the closed current direction selector switch Q_SW2 to the branch negative pole 5. From there, the load current flows via the closed branch selector switch S6 to supply current to the second power semiconductor M6 of the third branch 3. The load current then branches off at the center tap 13 of the third branch 3 and flows via the closed branch changeover switch AC_2 to the center tap 12 of the second branch 2. From there, the load current energizes the first power semiconductor M3 of the second branch 2 and then flows via the closed branch selector switch S3 to the branch positive pole 4 and from there via the closed current direction selector switch Q_SW3 to the load current source negative pole 62 of the load current source 6.Except for the aforementioned closed switches Q_SW2, S6, AC_2, S3, Q_SW3, all other load switches of the test and / or measurement system are open during the second current supply step in the reverse direction.

[0050] In the Fig. In the third current supply step of the load change test in the reverse direction, schematically illustrated in Figure 10, the load current flows from the load current source positive pole 61 of the load current source 6, first via the closed current direction selector switch Q_SW2 to the branch negative pole 5. From there, the load current flows via the closed branch selector switch S2 to supply current to the second power semiconductor M2 of the first branch 1. The load current then branches off at the center tap 11 of the first branch 1 and flows via the closed branch changeover switch AC_3 to the center tap 13 of the third branch 3. From there, the load current energizes the first power semiconductor M5 of the third branch 3 and then flows via the closed branch selector switch S5 to the branch positive pole 4 and from there via the closed current direction selector switch Q_SW3 to the load current source negative pole 62 of the load current source 6.Except for the aforementioned closed switches Q_SW2, S5, AC_3, S5, Q_SW3, all other load switches of the test and / or measurement system are open during the third current supply step in the reverse direction.

[0051] In the reverse direction, numerous variations in the current supply to the individual power semiconductors M1, M2; M3, M4; M5, and M6 are also possible. For example, it is also conceivable to supply current to power semiconductors M1 and M6 in the first current supply step, to power semiconductors M3 and M2 in the second current supply step, and to power semiconductors M5 and M4 in the third current supply step in the reverse direction.

[0052] For example, reverse current flow is advantageous for measuring the thermal impedance Z th of free wheeling diodes (FWD).

[0053] Combinations of switching patterns for supplying the arrangement with current in the forward and reverse directions are also possible.

[0054] In the test and / or measuring system according to the invention, for measurements of the thermal impedance Z th A current supply is selected for each case, and during the cooling phase, a cooling curve is measured on the current-carrying power semiconductor as well as on all other power semiconductors M1, M2, M3, M4, M5, and M6. The cooling curve can be acquired at a high sampling rate of, for example, 100 ksamples / s. This allows the thermal coupling of the power semiconductors M1, M2, M3, M4, M5, and M6 in the entire B6 arrangement to be recorded.

[0055] As already mentioned above, the test and / or measurement system according to the invention provides a large number of possible switch positions, with the following Table 1 giving examples of some switch positions for energizing individual or two power semiconductors M1, M2, M3, M4, M5, M6 of the arrangement: Table 1: Examples of switch positions for the arrangement of Figure 1 or 2 M1, M4 M3, M6 M5, M2 M5, M4 M1 M4 S1 1 0 0 0 1 0 S2 0 0 1 0 1 0 S3 0 1 0 0 0 1 S4 1 0 0 1 0 1 S5 0 0 1 1 0 0 S6 0 1 0 0 0 0 P1 0 0 0 0 0 0 P2 0 0 0 0 1 0 P3 0 0 0 0 0 1 P4 0 0 0 0 0 0 P5 0 0 0 0 0 0 P6 0 0 0 0 0 0 AC_1 1 0 0 0 0 0 AC_2 0 1 0 1 0 0 AC_3 0 0 1 0 0 0

[0056] In total, there are 15 useful switch positions for the load switches: - 6 for application-oriented power supply with load current via the branch changeover switches AC_1, AC_2, AC_3, - 6 for the current supply of individual power semiconductors and - 3 for the current supply of one half bridge each and 2 current directions for the load current: - where in the forward direction the current direction selector switches Q_SW1 and Q_SW4 are closed (ON) and - where in the reverse direction the current direction selector switches Q-SW2 and Q_SW3 are closed (ON).

[0057] The Fig. Figures 11 to 13 show examples of forward current flow through individual power semiconductors M1, M2, M3, M4, M5, and M6. The load current profile is shown schematically in each case using a thick dotted line.

[0058] In the Fig. 11, the load current flows from the load current source positive pole 61 of the load current source 6, first via the closed current direction selection load switch Q_SW1 to the branch positive pole 4. From there, the load current flows via the closed branch selection load switch S1 to energize the first power semiconductor M1 of the first branch 1. The load current then branches off at the center tap 11 of the first branch 1 and flows via the closed bypass switch P2 and the closed current direction selection load switch Q_SW4 to the load current source negative pole 62 of the load current source 6. Apart from the aforementioned closed switches Q_SW1, S1, P2, Q_SW4, all other load switches of the test and / or measuring system are open during the first energization step.

[0059] In the Fig. 12, the load current flows from the load current source positive pole 61 of the load current source 6, first via the closed current direction selection switch Q_SW1 to the branch positive pole 4. From there, the load current flows via the closed branch selection switch S3 and the closed bypass switch P3 to energize the second power semiconductor M4 of the second branch 2. The load current then flows via the closed branch selection switch S4 and the closed current direction selection switch Q_SW4 to the load current source negative pole 62 of the load current source 6. Apart from the aforementioned closed switches Q_SW1, S3, P3, S4 and Q_SW4, all other load switches of the test and / or measurement system are open during the second current supply step.

[0060] In the Fig. 13, the load current flows from the load current source positive pole 61 of the load current source 6, first via the closed current direction selection switch Q_SW1 to the branch positive pole 4. From there, the load current flows via the closed branch selection switch S5 to energize the first power semiconductor M5 of the third branch 3. The load current then flows via the closed bypass switch P6, the closed branch selection switch S6, and the closed current direction selection switch Q_SW4 to the load current source negative pole 62 of the load current source 6. Apart from the aforementioned closed switches Q_SW1, S5, S6, and Q_SW4, all other load switches of the test and / or measurement system are open during the third current supply step.

[0061] Current supply in the reverse direction can be carried out analogously, whereby the current direction selection load switches Q_SW2 and Q_SW3 are to be closed instead of the current direction selection load switches Q_SW1 and Q_SW4.

[0062] As already shown above with reference to Fig. 3, the test and / or measuring system according to the invention is a unidirectional or alternatively, as in Fig. As shown in Figure 4, a bidirectional connection of a measuring current source I_sense to the respective power semiconductor is provided. This connection enables the detection of the thermal impedance Z th of the respective power semiconductor M1, M2, M3, M4, M5, M6. The thermal impedance Z th of the respective power semiconductor M1, M2, M3, M4, M5, M6 is determined via the virtual junction temperature of the power semiconductor M1, M2, M3, M4, M5, M6, which in turn is determined via the temperature dependence of the threshold voltage of a pn junction.

[0063] For this purpose, the respective measuring current source I_sense supplies the respective power semiconductors M1, M2, M3, M4, M5, and M6 with a low-amplitude measuring current, for example, in a range of 10 mA to 100 mA. This requires that the respective measuring switch T is closed and no load current flows through the power semiconductors M1, M2, M3, M4, M5, and M6.

[0064] Depending on the type of power semiconductor to be tested or measured, there are differences. For example, when testing or measuring an IGBT, it is energized in the forward direction with the measuring current while the IGBT is switched on, whereby the temperature-dependent collector-emitter voltage V CE (T). When testing or measuring a diode, the diode is energized in the forward direction with the measuring current, whereby the temperature-dependent forward voltage V f(T). To test or measure a MISFET, it is reverse-biased while the MISFET is off, whereby the temperature-dependent source-drain voltage V SD (T) is recorded.

[0065] In the circuits of the test and / or measuring system according to the invention shown as examples in the figures, the B6 arrangement to be tested or measured can be extended by two or more power semiconductors in order to test several power semiconductors simultaneously and / or to measure the thermal impedance of the corresponding power semiconductors. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2021 210 336 A1

[0003]

Claims

[1] Test and / or measuring system which is electrically connected to at least one arrangement of power electronic components which has at least three parallel branches (1, 2, 3), each of which has a common branch positive pole (4) and a common branch negative pole (5), wherein each of the branches (1, 2, 3) has at least one first and at least one second power semiconductor (M1, M2; M3, M4; M5, M6), between which a center tap (11, 12, 13) is arranged, characterized by , that - the test and / or measuring system comprises a load current source (6) which is connected on the one hand to the branch positive pole (4) and on the other hand to the branch negative pole (5); - in each of the branches (1, 2, 3) a branch selector switch (S1, S3, S5) is connected between the branch positive pole (4) and the at least one first power semiconductor (M1, M3, M5) and a branch selector switch (S2, S4, S6) is connected between the branch negative pole (5) and the at least one second power semiconductor (M2, M4, M6); - a branch changeover switch (AC_1, AC_2, AC_3) is connected between the center taps (11, 12, 13) of the branches (1, 2, 3); - a bypass switch (P1, P2, P3, P4, P5, P6) is connected in parallel to the respective power semiconductor (M1, M2, M3, M4, M5, M6) which is connected on the one hand directly or via one of the branch selector switches (S1, S2, S3, S4, S5, S6) to the branch positive pole (4) or the branch negative pole (5) and on the other hand to the center tap (11, 12, 13) of the respective branch (1, 2, 3) or a bypass switch (P1, P2, P3, P4, P5, P6) is connected in parallel to a series circuit comprising the respective power semiconductor (M1, M2, M3, M4, M5, M6) and the respective associated branch selector switch (S1, S2, S3, S4, S5, S6) which is connected on the one hand to the branch positive pole (4) or the branch negative pole (5) and on the other hand to the center tap (11, 12, 13) of the respective branch (1, 2, 3) connected bypass switch (P1, P2, P3, P4, P5, P6) is switched; - a measuring current source (I_sense) is connected or connectable to each of the power semiconductors (M1, M2, M3, M4, M5, M6) via at least one measuring switch (T); and - a voltage measuring device is connected or can be connected in parallel to several or all of the power semiconductors (M1, M2, M3, M4, M5, M6). [2] Test and / or measuring system according to claim 1, characterized by in that a load current source positive pole (61) of the load current source (6) is connected or connectable to the branch positive pole (4) via a first current direction selection load switch (Q_SW1) and to the branch negative pole (5) via a second current direction selection load switch (Q_SW2), and a load current source negative pole (62) of the load current source (6) is connected or connectable to the branch positive pole (4) via a third current direction selection load switch (Q_SW3) and to the branch negative pole (5) via a fourth current direction selection load switch (Q_SW4). [3] Test and / or measuring system according to claim 1 or 2, characterized bythat a series arrangement comprising the at least one measuring switch (T) and the measuring current source (I_sense) is connected in parallel to at least one of the power semiconductors (M1, M2, M3, M4, M5, M6). [4] Test and / or measuring system according to claim 1 or 2, characterized byin that the at least one measuring switch (T) comprises at least four measuring switches, wherein a measuring current source positive pole of the measuring current source (I_sense) is connected or connectable via a first of the at least four measuring switches to a first terminal of the power semiconductor (M1, M2, M3, M4, M5, M6) and via a second of the at least four measuring switches to a second terminal of the power semiconductor (M1, M2, M3, M4, M5, M6), and a measuring current source negative pole of the measuring current source (I_sense) is connected or connectable via a third of the at least four measuring switches to the first terminal of the power semiconductor (M1, M2, M3, M4, M5, M6) and via a fourth of the at least four measuring switches to the second terminal of the power semiconductor (M1, M2, M3, M4, M5, M6). [5] Test and / or measuring method on a test and / or measuring system according to one of claims 1 to 4, characterized by , that individual or both of the at least one first power semiconductor (M1, M3, M5) and the at least one second power semiconductor (M2, M4, M6) are alternately supplied with current by means of the load current source (6) from one or two branches (1, 2, 3) of the arrangement of power electronic components, by switching individual ones of the branch selector load switches (S1, S2, S3, S4, S5, S6) and / or the branch alternating load switches (AC_1, AC_2, AC_3) and / or the bypass switches (P1, P2, P3, P4, P5, P6) in different configurations; at least one of the power semiconductors (M1, M2, M3, M4, M5, M6) not supplied with current by means of the load current source (6) is connected to the measuring current source (I_sense) connected in series with this measuring switch (T) by switching the measuring switch (T) connected in parallel to this power semiconductor (M1, M2, M3, M4, M5, M6) and is thereby supplied with a measuring current, and at least one measuring voltage is measured by the voltage measuring device connected in parallel to the respective power semiconductor (M1, M2, M3, M4, M5, M6). [6] Test and / or measuring method according to claim 5, characterized by that the branches (1, 2, 3) are supplied with current in different current directions by means of the load current source (6) in that a load current source positive pole (61) of the load current source (6) is connected to the branch positive pole (4) via a first current direction selection load switch (Q_SW1) or to the branch negative pole (5) via a second current direction selection load switch (Q_SW2), and a load current source negative pole (62) of the load current source (6) is connected to the branch positive pole (4) via a third current direction selection load switch (Q_SW3) or to the branch negative pole (5) via a fourth current direction selection load switch (Q_SW4).

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