Power tube test module, method and circuit board

Abstract

The invention provides a power tube testing module and method and a circuit board, and belongs to the technical field of power device testing, and the power tube testing module comprises a tested connecting end, a test accompanying circuit and a load switching circuit. Wherein the tested connecting end is connected with a power supply and is used for being connected with a tested tube; the test accompanying circuit is connected with the tested connecting end and is used for forming a half-bridge structure with the tested tube; the load switching circuit comprises a first end which is connected with the tested connecting end and the test accompanying circuit and a second end which is grounded, and the load switching circuit is used for enabling the half-bridge structure to work under different load conditions so as to test the performance of the tested tube under different load conditions; the tested tube is connected with the test accompanying circuit to form the half-bridge structure, so that the normal working state of the half-bridge structure formed by the tested tube and the test accompanying circuit is simulated, and then different load conditions are provided for the half-bridge structure through the load switching circuit, so that comprehensive test of the tested tube under various load conditions is realized.

Description

Technical Field

[0001] The present application relates to the technical field of power device testing, and in particular to a power tube testing module, method and circuit board. Background Art

[0002] Power tubes, such as insulated gate bipolar transistors (IGBTs), are widely used in various fields, such as AC motor drives, inverters, switching power supplies, uninterruptible power supply systems, new energy generation, and electric vehicle drive systems. Power tubes often need to work under different load conditions depending on the application field. The electrical characteristics under different load conditions usually have significant differences, which puts higher requirements on the switching performance and electromagnetic compatibility of power tubes.

[0003] At present, the testing methods for power tubes mainly focus on the measurement of their static parameters (such as saturation voltage drop, threshold voltage) and dynamic parameters (such as switching time, switching loss), and measure their performance parameters by simulating the working environment of the power tube in actual applications.

[0004] However, when testing power tubes, the power tubes usually only work under a single load condition, and it is not possible to fully simulate and test the performance of the power tubes under different load conditions. Therefore, how to test the power tubes under different load conditions is an urgent problem to be solved. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present application provides a power tube test module, method and circuit board.

[0006] In a first aspect, the present application provides a power tube test module, comprising:

[0007] The connection terminal to be tested is connected to the power supply and is used to access the pipe to be tested;

[0008] A companion test circuit, connected to the connection terminal to be tested, and used to form a half-bridge structure with the tube to be tested;

[0009] A load switching circuit, comprising a first end connected to the connection end to be tested and the accompanying test circuit and a second end connected to ground, wherein the load switching circuit is used to make the half-bridge structure work under different load conditions, so as to test the performance of the tube to be tested under different load conditions;

[0010] The load condition includes a resistive load, an inductive load, a capacitive load, a series resonant load or a parallel resonant load.

[0011] Optionally, the load switching circuit includes a resistive subcircuit, a multiplexing subcircuit and a switching subcircuit;

[0012] The resistive subcircuit can be selectively connected between the first end and the second end of the load switching circuit to enable the half-bridge structure to operate under a resistive load;

[0013] The switching subcircuit is connected to the multiplexing subcircuit and is used to control the multiplexing subcircuit to form an inductive load, a capacitive load, a series resonant load or a parallel resonant load and then be connected between the first end and the second end of the load switching circuit.

[0014] Optionally, the multiplexing subcircuit includes a first capacitor, a first inductor branch, and a second inductor branch;

[0015] One end of the first capacitor is connected to the first end of the load switching circuit, and the other end is connected to the switching subcircuit;

[0016] The switching subcircuit is connected to the first inductance branch and the second inductance branch, and is used to control the first inductance branch to be selectively connected in series with the first capacitor to form a series resonant load; and is used to control the second inductance branch to be selectively connected in parallel with the first capacitor to form a parallel resonant load or an inductive load.

[0017] Optionally, the first inductance branch includes a first inductor and a first resistor;

[0018] One end of the first inductor is connected to the switching subcircuit, and the other end of the first inductor is connected to the first resistor; the other end of the first resistor is grounded.

[0019] Optionally, the second inductor branch includes a second inductor and a second resistor;

[0020] One end of the second inductor is connected to the first capacitor and the first end of the load switching circuit, and the other end is connected to one end of the second resistor and the switching subcircuit; the other end of the second resistor is connected to the switching subcircuit.

[0021] Optionally, the switching subcircuit includes a first switch, a second switch, a third switch and a fourth switch;

[0022] One end of the first switch is connected to the second inductor and the first resistor, and the other end of the first switch is connected to the first inductor and a first node;

[0023] One end of the second switch is connected to the first resistor, and the other end is connected to the first inductor and one end of the third switch;

[0024] The other end of the third switch is connected to the first node;

[0025] One end of the fourth switch is connected to the first node, and the other end is grounded.

[0026] Optionally, the resistive subcircuit includes a fifth switch and a third resistor;

[0027] One end of the fifth switch is connected to the first end of the load switching circuit, and the other end is connected to the first end of the third resistor;

[0028] The other end of the third resistor is grounded.

[0029] Optionally, a protection circuit is further included, wherein the protection circuit is arranged between the connection terminal to be tested and the power supply;

[0030] The protection circuit includes a sixth switch, a seventh switch, a second capacitor and a fourth resistor;

[0031] One end of the sixth switch is connected to the power supply, and the other end is connected to the connection end to be tested;

[0032] The second capacitor is connected in parallel with the sixth switch;

[0033] One end of the seventh switch is connected to the second capacitor, and the other end is connected to one end of a fourth resistor and the ground;

[0034] The other end of the fourth resistor is connected to the second capacitor.

[0035] In a second aspect, in one embodiment, the present application provides a power tube testing method, including:

[0036] sequentially controlling the load switching circuit to form various load conditions;

[0037] Controlling the half-bridge structure formed by the companion test circuit and the tested tube to work normally under the current load condition;

[0038] The accompanying test circuit is controlled not to work, and the tested tube is controlled to be tested under the current load condition.

[0039] In a third aspect, in one embodiment, the present application provides a circuit board, comprising the power tube test circuit as described above.

[0040] Through the above technical solution, this application includes at least the following beneficial technical effects:

[0041] First, the half-bridge structure is formed by connecting the tube under test and the accompanying test circuit to simulate the normal working state of the half-bridge structure formed by the tube under test and the accompanying test circuit. Secondly, different load conditions are provided to the half-bridge structure through the load switching circuit, so as to realize the comprehensive test of the tube under test under various load conditions, and improve the efficiency and accuracy of the test of the tube under test. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0043] Figure 1 This is a schematic diagram of a power tube test module in one embodiment of the present application;

[0044] Figure 2 A schematic diagram of a load switching subcircuit in one embodiment of the present application;

[0045] Figure 3 This is a circuit connection structure diagram of a power tube test module in one embodiment of the present application;

[0046] Figure 4 A schematic diagram of current flow when a load switching circuit forms a resistive load in one embodiment of the present application;

[0047] Figure 5 A schematic diagram of current flow when a load switching circuit forms a capacitive load in one embodiment of the present application;

[0048] Figure 6 A schematic diagram of current flow when a load switching circuit forms a series resonant load in one embodiment of the present application;

[0049] Figure 7 A schematic diagram of current flow when a load switching circuit forms a parallel resonant load in one embodiment of the present application;

[0050] Figure 8 A schematic diagram of current flow of an inductive load formed by a load switching circuit in one embodiment of the present application;

[0051] Fig. 9 This is a flow chart of a power tube testing method in one embodiment of the present application.

[0052] Explanation of the reference numerals: 1. connection terminal under test; 2. accompanying test circuit; 3. load switching circuit; 31. resistive sub-circuit; 32. multiplexing sub-circuit; 321. first inductor branch; 322. second inductor branch; 33. switching sub-circuit; 4. protection circuit. DETAILED DESCRIPTION

[0053] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0054] In the description of the present application, it should be understood that the terms "first" and "second" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. In the present application, the word "exemplary" is used to mean "used as an example, illustration or description". Any embodiment described as "exemplary" in the present application is not necessarily interpreted as being more preferred or more advantageous than other embodiments. In order to enable any technician in the field to implement and use the present application, the following description is given. In the following description, details are listed for the purpose of explanation. It should be understood that a person of ordinary skill in the art can recognize that the present application can also be implemented without using these specific details. In other examples, well-known structures and processes will not be elaborated in detail to avoid unnecessary details that make the description of the present application obscure. Therefore, the present application is not intended to be limited to the embodiments shown, but is consistent with the widest range of principles and features disclosed in the present application.

[0055] First, as Figure 1-Figure 3 As shown, in one embodiment, the present application provides a power tube test module, which includes a connection terminal 1 under test, a test circuit 2, and a load switching circuit 3. The connection terminal 1 under test is connected to the power supply VCC for connecting to the tube QT under test; the test circuit 2 is connected to the connection terminal 1 under test and is used to form a half-bridge structure with the tube QT under test; the load switching circuit 3 includes a first end connected to the connection terminal 1 under test and the test circuit 2 and a second end connected to the ground. The load switching circuit 3 is used to make the half-bridge structure work under different load conditions, so as to test the performance of the tube QT under different load conditions.

[0056] The load condition includes a resistive load, an inductive load, a capacitive load, a series resonant load or a parallel resonant load.

[0057] As an example, the tube QT under test can be connected to the connection terminal 1 under test in a detachable manner so as to replace the tube QT under test. The connection terminal 1 under test can include a first connection terminal, a second connection terminal and a third connection terminal, the first connection terminal can be connected to the power supply VCC, the second connection terminal can be connected to the second node B with the accompanying test circuit 2, and the second node B is the first end of the load switching circuit 3; the third connection terminal can be used to access the first control signal PWM1, for example, the first connection terminal can be connected to the first electrode of the tube QT under test, the second connection terminal can be connected to the second electrode of the tube QT under test, and the third connection terminal can be connected to the control electrode of the tube QT under test, so that the control of the tube QT under test can be realized through the first control signal PWM1.

[0058] The accompanying test circuit 2 includes an accompanying test tube QC, and the accompanying test tube QC includes a first electrode connected to the second node B, a grounded second electrode, and a control electrode for accessing the second control signal PWM2.

[0059] As an example, first, it is necessary to control the half-bridge structure formed by the measured tube QT and the accompanying measured tube QC to work normally, that is, when it is necessary to output a positive half-cycle voltage, the measured tube QT is controlled to be turned on by the first control signal PWM1, and the accompanying measured tube QC is controlled to be turned off by the second control signal PWM2, so that the current flows from the power supply VCC through the measured tube QT to the load switching circuit 3, and then flows back to the ground through the body diode of the accompanying measured tube QC to form a loop. When it is necessary to output a negative half-cycle voltage, the first control signal PWM1 controls the measured tube QT to be turned off, and the second control signal PWM2 controls the accompanying measured tube QC to be turned on, and the current flows from the positive electrode of the power supply VCC through the accompanying measured tube QC to the load switching circuit 3, thereby ensuring that the current flows continuously on the load switching circuit 3, forming a stable AC output voltage, and simulating the actual working state of the measured tube QT in the half-bridge structure. Moreover, the waveforms of the first control signal PWM1 and the second control signal PWM2 are always in complementary phases, so that the measured tube QT can be placed at different powers by adjusting the duty ratios of the first control signal PWM1 and the second control signal PWM2 to simulate the working state of the measured tube QT at different powers.

[0060] Then, after the half-bridge structure works normally for a preset time, the test process of the tested tube QT is immediately entered. Taking the double pulse test of the tested tube QT as an example, the second control signal PWM2 is used to control the accompanying test tube QC to remain in the off state during the entire test process; two pulse signals are applied to the tested tube QT through the first control signal PWM1. For example, the first pulse is used to trigger the tested tube QT to turn on, so that the current rises linearly, and then the tested tube QT is turned off, and the voltage spike caused by the parasitic inductance can be measured. The second pulse triggers the tested tube QT to turn on again. At this time, the body diode of the tested tube QT enters the reverse recovery state to achieve commutation. After the second pulse ends, the tested tube QT is turned off again. Through the test of the above two pulse signals, the switching characteristics of the tested tube QT and the reverse recovery behavior of the body diode can be evaluated. It should be noted that in the test process of the tested tube QT, in addition to testing the switching characteristics and reverse recovery behavior, other parameters can also be tested according to actual needs, such as turn-on delay time, turn-on energy, turn-off delay time, turn-off time and turn-off energy.

[0061] In the above implementation, firstly, the half-bridge structure is formed by connecting the tube under test QT and the accompanying test circuit 2 to simulate the normal working state of the half-bridge structure formed by the tube under test QT and the accompanying test circuit 2. Secondly, different load conditions are provided to the half-bridge structure through the load switching circuit 3, so that the comprehensive test of the tube under test QT under various load conditions is realized, and the efficiency and accuracy of the test of the tube under test QT are improved.

[0062] Reference Figure 2 As an implementation method of the load switching circuit 3, the load switching circuit 3 includes a resistive subcircuit 31, a multiplexing subcircuit 32 and a switching subcircuit 33; wherein the resistive subcircuit 31 can be selectively connected between the first end and the second end of the load switching circuit 3 so that the half-bridge structure works under a resistive load; the switching subcircuit 33 is connected to the multiplexing subcircuit 32, and is used to control the multiplexing subcircuit 32 to form an inductive load, a capacitive load, a series resonant load or a parallel resonant load and then connected between the first end and the second end of the load switching circuit 3.

[0063] In the above implementation, the resistive subcircuit 31 can be selectively connected between the first end and the second end of the load switching circuit 3 to ensure that the half-bridge structure can work normally under resistive load conditions. Through the multiplexing subcircuit 32 and the switching subcircuit 33, an inductive load, a capacitive load, a series resonant load or a parallel resonant load is formed and connected between the first end and the second end of the load switching circuit 3. In this way, through the cooperation of the multiplexing subcircuit 32 and the switching subcircuit 33, while realizing the simulation and switching of multiple load conditions, the number of required components can be reduced, thereby reducing the cost of the test module.

[0064] Reference Figure 3As an implementation of the multiplexing sub-circuit 32, the multiplexing sub-circuit 32 includes a first capacitor C1, a first inductance branch 321 and a second inductance branch 322; one end of the first capacitor C1 is connected to the first end of the load switching circuit 3, and the other end is connected to the switching sub-circuit 33; the switching sub-circuit 33 is connected to the first inductance branch 321 and the second inductance branch 322, and is used to control the first inductance branch 321 to be selectively connected in series with the first capacitor C1 to form a series resonant load; and is used to control the second inductance branch 322 to be selectively connected in parallel with the first capacitor C1 to form a parallel resonant load or an inductive load.

[0065] Reference Figure 3 As an implementation of the first inductor branch 321, the first inductor branch 321 includes a first inductor L1 and a first resistor R1; wherein one end of the first inductor L1 is connected to the switching subcircuit 33, and the other end is connected to the first resistor R1; the other end of the first resistor R1 is grounded.

[0066] As an example, the first inductor L1, the first resistor R1 and the first capacitor C1 are connected in series by switching the subcircuit 33 to form a series resonant load. For example, the series resonant load is usually used in circuits such as high-frequency inverters and resonant converters. At a specific frequency, the impedances of the inductor and the capacitor cancel each other out to form a low-impedance path, which will cause the tested tube QT to withstand a higher voltage stress. Therefore, the test tube can be tested under the series resonant load to test its performance in a high voltage and high frequency environment.

[0067] Reference Figure 3 As an implementation of the second inductor branch 322, the second inductor branch 322 includes a second inductor L2 and a second resistor R2; one end of the second inductor L2 is connected to the first capacitor C1 and the first end of the load switching circuit 3, and the other end is connected to one end of the second resistor R2 and the switching sub-circuit 33; the other end of the second resistor R2 is connected to the switching sub-circuit 33.

[0068] As an example, by switching the subcircuit 33, the second inductor L2 and the first capacitor C1 are connected in series and then connected in parallel with the first capacitor C1 to form a parallel resonant load. For example, the parallel resonant load can be applied to circuits such as filters and impedance matching networks. Under a specific frequency, the inductor and the capacitor impedance of the parallel resonant load are added to form a high impedance path, thereby suppressing the passage of current at a specific frequency. Due to the suppression effect of the parallel resonant structure on the current, the measured tube QT is mainly subjected to current stress under the parallel resonant load, so as to test the current control ability of the measured tube QT.

[0069] As an example, the second inductor L2 and the first capacitor C1 are connected in parallel to form an inductive load by switching the subcircuit 33. The inductance of the second inductor L2 should be greater than the capacitance of the first capacitor C1 to ensure that they present the characteristics of an inductive load after being connected in parallel.

[0070] Reference Figure 3 As an implementation of the switching subcircuit 33, the switching subcircuit 33 includes a first switch K1, a second switch K2, a third switch K3 and a fourth switch K4; wherein, one end of the first switch K1 is connected to the second inductor L2 and the first resistor R1, and the other end is connected to the first inductor L1 and the first node A; one end of the second switch K2 is connected to the first resistor R1, and the other end is connected to the first inductor L1 and one end of the third switch K3; the other end of the third switch K3 is connected to the first node A; one end of the fourth switch K4 is connected to the first node A, and the other end is grounded.

[0071] In the above implementation, the states of the first switch K1, the second switch K2, the third switch K3 and the fourth switch K4 are coordinated to realize that the multiplexing sub-circuit 32 forms an inductive load, a capacitive load, a series resonant load or a parallel resonant load and is connected between the first end and the second end of the load switching circuit 3. Compared with the solution of replacing the load, the states of the first switch K1, the second switch K2, the third switch K3 and the fourth switch K4 are controlled to switch the load, thereby improving the test efficiency.

[0072] Reference Figure 3 As an implementation of the resistive subcircuit 31, the resistive subcircuit 31 includes a fifth switch K5 and a third resistor R3; one end of the fifth switch K5 is connected to the first end of the load switching circuit 3, and the other end is connected to the first end of the third resistor R3; the other end of the third resistor R3 is grounded.

[0073] Reference Figure 3 As a further implementation of the power tube test module, the power tube test module also includes a protection circuit 4, which is arranged between the tested connection terminal 1 and the power supply VCC; the protection circuit 4 includes a sixth switch K6, a seventh switch K7, a second capacitor C2 and a fourth resistor R4; one end of the sixth switch K6 is connected to the power supply VCC, and the other end is connected to the tested connection terminal 1; the second capacitor C2 is connected to the sixth switch K6 in parallel; one end of the seventh switch K7 is connected to the second capacitor C2, and the other end is connected to one end of the fourth resistor R4 and ground; the other end of the fourth resistor R4 is connected to the second capacitor C2.

[0074] In the above embodiment, the sixth switch K6 is used to cut off the connection between the power supply VCC and the tested tube QT when no test is required, and the seventh switch K7 is closed to form a discharge loop formed by the fourth resistor R4 and the second capacitor C2. After the test is completed, the voltage in the load switching circuit 3 is quickly discharged to improve safety.

[0075] Reference Figure 4-Figure 8 , the present disclosure exemplarily describes the process of the load switching circuit 3 forming different load conditions.

[0076] Combination Figure 4 , Figure 4 It is a schematic diagram of the current flow when the load switching circuit 3 forms a resistive load. When testing the performance of the power tube working under the resistive load, the fifth switch K5 is closed, and the first switch K1, the second switch K2, the third switch K3 and the fourth switch K4 are all opened, so that the current flows from the tested tube QT through the third resistor R3 to the ground, so that the tested tube QT works under the condition of resistive load.

[0077] Combination Figure 5 , Figure 5 It is a schematic diagram of the current flow direction when the load switching circuit 3 forms a capacitive load. When testing the performance of the power tube working under the capacitive load, the fourth switch K4 is closed, and the first switch K1, the second switch K2, the third switch K3 and the fifth switch K5 are all opened, so that the current flows from the tube QT under test through the first capacitor C1 to the ground, so that the tube QT under test works under the condition of capacitive load.

[0078] Combination Figure 6 , Figure 6 It is a schematic diagram of the current flow direction when the load switching circuit 3 forms a series resonant load. When testing the performance of the power tube working under the series resonant load, the third switch K3 is closed, and the first switch K1, the second switch K2, the fourth switch K4 and the fifth switch K5 are all opened, so that the current flows out of the tube QT under test and then flows to the ground after passing through the first inductor L1 and the first resistor R1 in sequence, so that the tube QT under test works under the condition of the series resonant load.

[0079] Combination Figure 7 , Figure 7It is a schematic diagram of the current flow direction when the load switching circuit 3 forms a parallel resonant load. When testing the performance of the power tube working under the parallel resonant load, the second switch K2, the third switch K3 and the fourth switch K4 are closed, and the first switch K1 and the fifth switch K5 are opened, so that the current flows out of the tube QT under test through the second inductor L2 and the second resistor R2 in one way, and the other way through the first capacitor C1. The two currents converge at the first node A and flow to the ground through the fourth switch K4. That is, at this time, the second inductor L2 and the second resistor R2 are connected in series and then connected in parallel with the first capacitor C1, that is, the tube QT under test works under the condition of parallel resonant load.

[0080] Combination Figure 8 , Figure 8 It is a schematic diagram of the current flow direction when the load switching circuit 3 forms an inductive load. When testing the performance of the power tube working under the inductive load, the first switch K1 and the fourth switch K4 are closed, and the second switch K2, the third switch K3 and the fifth switch K5 are all opened, so that the current flows out of the tested tube QT and flows to the ground through the second inductor L2, so that the tested tube QT works under the condition of inductive load.

[0081] Reference Fig. 9 In the second aspect, in one embodiment, the present application provides a power tube testing method, including steps S101 to S103, which are introduced below.

[0082] Step S101: sequentially controlling the load switching circuit 3 to form various load conditions.

[0083] As an example, one or more of a resistive load, an inductive load, a capacitive load, a series resonant load, or a parallel resonant load may be tested according to actual needs.

[0084] Step S102: controlling the half-bridge structure formed by the companion test circuit 2 and the tested tube QT to operate normally under the current load condition.

[0085] The normal operation means that the accompanying test circuit 2 and the tested tube QT in the half-bridge structure are alternately turned on to output a square wave signal.

[0086] Step S103: Control the accompanying test circuit 2 not to work, and control the tested tube QT to be tested under the current load condition.

[0087] In a third aspect, in one embodiment, the present application provides a circuit board, comprising the power tube test circuit as described above.

[0088] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0089] The embodiments, implementation methods and related technical features of the present application can be combined and replaced with each other without conflict.

[0090] The above are only preferred embodiments of the present application and do not constitute any form of limitation to the present application. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. A power tube test module, characterized in that: include: The connection terminal to be tested is connected to the power supply and is used to access the pipe to be tested; A companion test circuit, connected to the connection terminal to be tested, and used to form a half-bridge structure with the tube to be tested; A load switching circuit, comprising a first end connected to the connection end to be tested and the accompanying test circuit and a second end connected to ground, wherein the load switching circuit is used to make the half-bridge structure work under different load conditions, so as to test the performance of the tube to be tested under different load conditions; The load condition includes a resistive load, an inductive load, a capacitive load, a series resonant load or a parallel resonant load.

2. The power tube test module according to claim 1, characterized in that: The load switching circuit includes a resistive subcircuit, a multiplexing subcircuit and a switching subcircuit; The resistive subcircuit can be selectively connected between the first end and the second end of the load switching circuit to enable the half-bridge structure to operate under a resistive load; The switching subcircuit is connected to the multiplexing subcircuit and is used to control the multiplexing subcircuit to form an inductive load, a capacitive load, a series resonant load or a parallel resonant load and then be connected between the first end and the second end of the load switching circuit.

3. The power tube test module according to claim 2, characterized in that: The multiplexing subcircuit includes a first capacitor, a first inductor branch, and a second inductor branch; One end of the first capacitor is connected to the first end of the load switching circuit, and the other end is connected to the switching subcircuit; The switching subcircuit is connected to the first inductance branch and the second inductance branch, and is used to control the first inductance branch to be selectively connected in series with the first capacitor to form a series resonant load; and is used to control the second inductance branch to be selectively connected in parallel with the first capacitor to form a parallel resonant load or an inductive load.

4. The power tube test module according to claim 3, characterized in that: The first inductor branch includes a first inductor and a first resistor; One end of the first inductor is connected to the switching subcircuit, and the other end of the first inductor is connected to the first resistor; the other end of the first resistor is grounded.

5. The power tube test module according to claim 4, characterized in that: The second inductor branch includes a second inductor and a second resistor; One end of the second inductor is connected to the first capacitor and the first end of the load switching circuit, and the other end is connected to one end of the second resistor and the switching subcircuit; the other end of the second resistor is connected to the switching subcircuit.

6. The power tube test module according to claim 5, characterized in that: The switching subcircuit includes a first switch, a second switch, a third switch and a fourth switch; One end of the first switch is connected to the second inductor and the first resistor, and the other end of the first switch is connected to the first inductor and a first node; One end of the second switch is connected to the first resistor, and the other end is connected to the first inductor and one end of the third switch; The other end of the third switch is connected to the first node; One end of the fourth switch is connected to the first node, and the other end is grounded.

7. The power tube test module according to claim 2, characterized in that: The resistive subcircuit includes a fifth switch and a third resistor; One end of the fifth switch is connected to the first end of the load switching circuit, and the other end is connected to the first end of the third resistor; The other end of the third resistor is grounded.

8. The power tube test module according to claim 1, characterized in that: It also includes a protection circuit, which is arranged between the connection terminal to be tested and the power supply; The protection circuit includes a sixth switch, a seventh switch, a second capacitor and a fourth resistor (R4); One end of the sixth switch is connected to the power supply, and the other end is connected to the connection end to be tested; The second capacitor is connected in parallel with the sixth switch; One end of the seventh switch is connected to the second capacitor, and the other end is connected to one end of a fourth resistor and the ground; The other end of the fourth resistor is connected to the second capacitor.

9. A power tube testing method, characterized in that: The power tube test module according to any one of claims 1 to 8 is implemented, and the method comprises: sequentially controlling the load switching circuit to form various load conditions; Controlling the half-bridge structure formed by the companion test circuit and the tested tube to work normally under the current load condition; The accompanying test circuit is controlled not to work, and the tested tube is controlled to be tested under the current load condition.

10. A circuit board, characterized in that: It comprises a power tube test circuit as described in any one of claims 1 to 8.

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