Equivalent application condition experiment circuit and its experimental method

Abstract

The present disclosure relates to an equivalent application condition experimental circuit and an experimental method thereof. The equivalent application condition experimental circuit includes: a device under test and a controllable power supply system. The controllable power supply system is connected to both ends of the device under test and is configured to: generate a controllable voltage stress across the device under test when the device under test is in a blocking state; and generate a controllable current stress across the device under test when the device under test is in a conducting state; wherein the waveform changes of the controllable voltage stress and the controllable current stress both conform to the waveform changes of the corresponding electrical stress of the device under test in the actual application condition. The present disclosure is beneficial to improving the equivalence between the experimental electrical stress and the actual condition electrical stress of the device under test, thereby effectively improving the experimental reliability of the equivalent application condition experimental circuit and effectively reducing the reactive power generated during its operation.

Description

Technical Field

[0001] The present disclosure relates to the field of power electronics technology, and particularly to an equivalent application condition experimental circuit and an experimental method thereof. Background Art

[0002] The equivalent application condition experiment is to use a dedicated circuit and method to generate stress conditions similar to the application conditions of the device under test or the core device in the device under test, so as to verify the functional integrity and long-term reliability of the device under test during actual operation. Currently, in the example where the device under test is a power semiconductor device or a component of a converter valve group, a converter valve equivalent application condition experimental circuit can be used for the experiment to verify the power semiconductor device or the component of the converter valve group. However, in the existing converter valve equivalent application condition experimental circuit, there are still significant differences between the equivalent waveform of the transient current stress that the device under test can generate and the transient current stress waveform generated by the converter valve under actual operating conditions, which needs to be further optimized or redesigned. Summary of the Invention

[0003] Based on this, the embodiments of the present disclosure provide an equivalent application condition experimental circuit and an experimental method thereof, which are beneficial to improving the equivalence between the experimental electrical stress of the device under test and the electrical stress under actual conditions, thereby effectively improving the experimental reliability of the equivalent application condition experimental circuit and reducing the reactive power generated during its operation.

[0004] To achieve the above object, in a first aspect, some embodiments of the present disclosure provide an equivalent application condition experimental circuit, including: a device under test and a controllable power supply system. The controllable power supply system is connected to both ends of the device under test and is configured to: generate a controllable voltage stress at both ends of the device under test when the device under test is in a blocking state; and generate a controllable current stress at both ends of the device under test when the device under test is in a conducting state; wherein, the waveform changes of the controllable voltage stress and the controllable current stress both conform to the waveform changes of the corresponding electrical stress of the device under test in actual application conditions.

[0005] In some embodiments of the present disclosure, the controllable power supply system includes a first programmable power supply system and a second programmable power supply system respectively connected to both ends of the device under test; wherein, the circuit structures of the first programmable power supply system and the second programmable power supply system are the same.

[0006] In some embodiments of the present disclosure, both the first programmable power supply system and the second programmable power supply system include: a first three-phase power supply and a second three-phase power supply with opposite phases, a converter, and an inductor. The first three-phase power supply and the second three-phase power supply are connected to a common ground; the input ends of the converter are respectively connected to the output end of the first three-phase power supply, the output end of the second three-phase power supply, and the common ground; one end of the inductor is connected to the output end of the converter, and the other end is connected to the device under test.

[0007] In some embodiments of the present disclosure, the converter includes: a plurality of input terminals, a plurality of bidirectional switching devices, and an output terminal. The plurality of input terminals are respectively connected to each phase circuit of a first three-phase power supply and a second three-phase power supply, as well as a common ground. The plurality of bidirectional switching devices correspond one-to-one to the plurality of input terminals; and one end of any bidirectional switching device is connected to the input terminal, and the other end is connected to the output terminal. Accordingly, the converter is configured to: in response to the switching control signals of the bidirectional switching devices, select one input terminal from the plurality of input terminals to connect to the output terminal at a target time.

[0008] In some embodiments of the present disclosure, the implementation manner of the bidirectional switching device includes any one of the following.

[0009] Embodiment 1: The bidirectional switching device includes a first bidirectional switching unit. The first bidirectional switching unit includes: a diode full bridge and a transistor connected in parallel to the DC side of the diode full bridge, and the AC side of the diode full bridge is connected to the corresponding input terminal.

[0010] Embodiment 2: The bidirectional switching device includes at least two stages of first bidirectional switching units connected in series in sequence; wherein, the non-series AC sides of the first-stage and the last-stage diode full bridges are connected to the corresponding input terminals.

[0011] Embodiment 3: The bidirectional switching device includes a second bidirectional switching unit. The second bidirectional switching unit includes: a diode group full bridge and a transistor group connected in parallel to the DC side of the diode group full bridge; wherein, the bridge arms of the diode group full bridge include at least two stages of diodes connected in series; the transistor group includes at least two stages of transistors connected in series.

[0012] Embodiment 4: The bidirectional switching device includes at least two stages of second bidirectional switching units connected in series in sequence; wherein, the non-series AC sides of the diode group full bridges in the first-stage and the last-stage second bidirectional switching units are connected to the corresponding input terminals.

[0013] Embodiment 5: The bidirectional switching device includes a third bidirectional switching unit. The third bidirectional switching unit includes: a first transistor and a second transistor connected in reverse series, the first transistor is configured to block the forward voltage and control the forward current, and the second transistor is configured to block the reverse voltage and control the reverse current.

[0014] Embodiment 6: The bidirectional switching device includes at least two stages of third bidirectional switching units connected in series in sequence.

[0015] Embodiment Seven. The bidirectional switch device includes a fourth bidirectional switch unit. The fourth bidirectional switch unit includes: a first transistor group and a second transistor group connected in series in reverse; the first transistor group is used to block the forward voltage and control the forward current, and includes at least two stages of first transistors connected in series in sequence; the second transistor group is used to block the reverse voltage and control the reverse current, and includes at least two stages of second transistors connected in series in sequence.

[0016] Embodiment Eight. The bidirectional switch device includes: at least two stages of fourth bidirectional switch units connected in series in sequence.

[0017] Embodiment Nine. The bidirectional switch device includes: a fifth bidirectional switch unit. The fifth bidirectional switch unit includes two reverse-parallel reverse-blocking power semiconductor devices, or two series modules connected in reverse parallel; wherein, the series module is formed by connecting in series at least one of an insulated gate bipolar transistor, an integrated gate-commutated thyristor, a field effect transistor, or a high electron mobility transistor and a diode; one series module is used to control the forward current, and the other series module is used to control the reverse current.

[0018] Embodiment Ten. The bidirectional switch device includes: at least two stages of fifth bidirectional switch units connected in series in sequence.

[0019] Embodiment Eleven. The bidirectional switch device includes: a sixth bidirectional switch unit. The sixth bidirectional switch unit includes two series module groups connected in reverse parallel; wherein, the series module group includes at least two stages of series modules connected in series in sequence; one series module group is used to control the forward current, and the other series module group is used to control the reverse current.

[0020] Embodiment Twelve. The bidirectional switch device includes: at least two stages of sixth bidirectional switch units connected in series in sequence.

[0021] In some other embodiments of the present disclosure, the controllable power supply system includes: a first three-phase power supply, a transformer, a first converter, and a second converter. The transformer is connected to the first three-phase power supply and connected to the common ground. The input end of the first converter is connected to the transformer and the common ground, and its output end is connected to one end of the device under test through an inductor. The input end of the second converter is connected in parallel with the first converter and connected to the transformer and the common ground, and its output end is directly connected to the other end of the device under test.

[0022] Exemplarily, the transformer includes a DYY-type transformer.

[0023] In some embodiments of the present disclosure, the device under test includes, but is not limited to, a converter valve group component or a power semiconductor device.

[0024] Second aspect, some embodiments of the present disclosure also provide an experimental method for an equivalent application condition experimental circuit, which is used to perform an equivalent application condition experiment on the equivalent application condition experimental circuit described in the above embodiments. The experimental method includes the following steps.

[0025] When the device under test is in the blocking state, the controllable power supply system generates a controllable voltage stress across the device under test.

[0026] When the device under test is in the conducting state, the controllable power supply system generates a controllable current stress across the device under test.

[0027] Here, the waveform changes of both the controllable voltage stress and the controllable current stress conform to the waveform changes of the corresponding electrical stress of the device under test in the actual application conditions.

[0028] In some embodiments of the present disclosure, the controllable power supply system includes two converters respectively connected to the device under test, and at least one converter is connected to the device under test through an inductor. The experimental method further includes: when the device under test is in the blocking state, selecting and turning on the target input terminals in each converter so that the voltage difference between the output terminals of the two converters generates a controllable voltage stress across the device under test; when the device under test is in the conducting state, selecting and turning on the target input terminals in each converter so that the voltage difference between the output terminals of the two converters generates a controllable current stress across the device under test through the inductor.

[0029] The embodiments of the present disclosure can / at least have the following advantages:

[0030] In the embodiments of the present disclosure, by connecting a controllable power supply system across the device under test and enabling the controllable power supply system to generate a controllable voltage stress across the device under test when the device under test is in the blocking state and a controllable current stress across the device under test when the device under test is in the conducting state, while ensuring that the waveform changes of both the controllable voltage stress and the controllable current stress conform to the waveform changes of the corresponding electrical stress of the device under test in the actual application conditions. In this way, the embodiments of the present disclosure can precisely regulate the output electrical signal through the controllable power supply system, thereby generating electrical stress that is approximately completely equivalent to the actual application conditions across the device under test, thus improving the equivalence between the experimental electrical stress and the actual operating condition electrical stress of the device under test, and further effectively improving the experimental reliability of the equivalent application condition experimental circuit and effectively reducing the reactive power generated during its operation.

[0031] Details of one or more embodiments of the present disclosure are set forth in the following drawings and description. Other features, objects, and advantages of the present disclosure will become apparent from the specification, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] To more clearly illustrate the technical solutions in the embodiments of the present disclosure or in the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present disclosure. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0033] Figure 1 It is a schematic diagram of the circuit topology of a six-pulse converter valve provided in some embodiments;

[0034] Figure 2 For Figure 1 It is a schematic diagram of the electrical stress waveform of a group of bridge arms when the six-pulse converter valve shown operates in the inverter mode;

[0035] Figure 3 It is a schematic diagram of the circuit topology of an equivalent application condition experiment circuit provided in some embodiments;

[0036] Figure 4 For Figure 3 It is a schematic diagram of an electrical stress waveform generated by the equivalent application condition experiment circuit shown;

[0037] Figure 5 It is a schematic diagram of the circuit topology of another equivalent application condition experiment circuit provided in some embodiments;

[0038] Figure 6 It is a schematic diagram of the circuit topology of a converter provided in some embodiments;

[0039] Figure 7 It is a comparative schematic diagram of the circuit topologies of different bidirectional switch devices provided in some embodiments;

[0040] Figure 8 It is a schematic diagram of the circuit topology of yet another equivalent application condition experiment circuit provided in some embodiments;

[0041] Figure 9 It is a flowchart of an experimental method for an equivalent application condition experiment circuit provided in some embodiments;

[0042] Figure 10 For Figure 8 It is a schematic diagram of an electrical stress waveform generated by the equivalent application condition experiment circuit shown. Detailed implementation manners

[0043] To facilitate the understanding of the present disclosure, the present disclosure will be described more comprehensively below with reference to the relevant accompanying drawings. Preferred embodiments of the present disclosure are shown in the accompanying drawings. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present disclosure more thorough and comprehensive.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this disclosure belongs. The terms used in the description of the present disclosure herein are for the purpose of describing specific embodiments only and are not intended to limit the present disclosure.

[0045] It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers, and / or parts, these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or part from another element, component, region, layer, or part. Thus, without departing from the teachings of the present invention, the first element, component, region, layer, or part discussed below may be referred to as the second element, component, region, layer, or part.

[0046] It should be understood that when an element is considered to be "connected" to another element, it may be directly connected to the other element or connected to the other element through an intermediate element. In addition, in the following embodiments, "connection", if there is a transfer of electrical signals or data between the connected objects, should be understood as "electrical connection", "communication connection", etc.

[0047] It should be understood that the singular forms "a", "an", and "the" may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms "comprise / include" or "have", etc. specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, when used herein, the term "and / or" includes any and all combinations of the related listed items.

[0048] The equivalent application condition experiment is to use a dedicated circuit and method to generate stress conditions similar to the application conditions of the device under test or the core device in the device under test, so as to verify the functional integrity and long-term reliability of the device under test during actual operation. Currently, in the example where the device under test is a power semiconductor device or a component of a converter valve group, an equivalent application condition experiment circuit of the converter valve can be used for the experiment to verify the power semiconductor device or the component of the converter valve group.

[0049] In some embodiments of the present disclosure, taking a six-pulse converter valve as an example, the equivalent application condition experimental circuit thereof and its experimental method are introduced.

[0050] Exemplarily, Figure 1 shows the circuit topology of a six-pulse converter valve. In this six-pulse converter valve, the six bridge arms from T 1 to T 6 are interconnected to form a three-phase full-bridge structure; and, the midpoints of each phase full-bridge are connected to the AC side, and both ends of each phase full-bridge are connected to the DC side. In this way, the current direction is fixed and can only flow from the anode to the cathode of each bridge arm. The six bridge arms from T 1 to T 6 can be triggered to conduct in sequence at an electrical angle interval of 60°. Among them, the triggering conduction moment of the T 1 bridge arm is adjustable, and the phase difference between the T 1 bridge arm and the reference phase of the grid voltage forms a triggering angle. When the triggering angle is small, the converter valve operates in the rectification mode, the voltage at the upper end of the DC side is higher than that at the lower end, and energy flows from the AC side to the DC side; when the triggering angle is large, the converter valve operates in the inversion mode, the voltage at the upper end of the DC side is lower than that at the lower end, and energy flows from the DC side to the AC side.

[0051] Figure 2 Schematically shows the electrical stress waveform of a group of bridge arms when the converter valve operates in the inversion mode. As shown in Figure 2 , at the moment of t 1 , the current bridge arm is triggered to conduct, and the voltage stress is clamped to zero. The previously conducting bridge arm in the same upper and lower bridge positions commutates to the current bridge arm, and the current stress of the current bridge arm starts to rise and reaches the maximum value at the moment of t 2 , and the current commutation process ends. The time between t 1 and t 2 is the commutation overlap time of the bridge arm. When the inductance of the DC side of the converter valve is large enough and the triggering angle is far from 90° electrical angle, the current stress of the current bridge arm remains approximately unchanged between t 2 and t 3 . At the moment of t 3 , the next bridge arm in the same upper and lower bridge positions is triggered to conduct, and the current bridge arm commutates to this bridge arm. The current stress of the current bridge arm starts to decline and reaches zero at the moment of t 4 , presenting an overall trapezoidal waveform. After the current of the current bridge arm drops through zero, the current bridge arm resumes the blocking state and starts to bear the reverse voltage stress. After the moment of t 4 , the voltage stress of the current bridge arm shows a sawtooth waveform affected by the commutation of other bridge arms and the commutation overlap time.

[0052] Figure 3 Schematically shows the circuit topology of an equivalent application condition experimental circuit of a converter valve. As shown in Figure 3As shown, the voltage source subsystem, the current source subsystem, and the device under test are topologically connected in parallel. During the equivalent application condition experiment, the control instructions of the voltage source subsystem, the current source subsystem, and the device under test cooperate with each other in time sequence. The voltage source subsystem applies voltage stress to the device under test when it is in the blocking state, and the current source subsystem applies current stress to it when it is in the conducting state. The electrical stress waveform generated by the equivalent application condition experiment circuit of the converter valve is as Figure 4 shown.

[0053] Please refer to Figure 3 and Figure 4 for understanding. In the equivalent application condition experiment circuit of the converter valve shown in Figure 3 , the voltage stress output by the voltage source subsystem comes from the voltage of capacitor C s . Capacitor C s and inductor L 1 and inductor L 2 form two pairs of series resonance circuits. The semi-controlled power devices V 3 and V 5 are respectively used to start the aforementioned two groups of series resonance circuits. The semi-controlled power device V 2 is used to control the DC voltage source u DC to recover the voltage of capacitor C s . The semi-controlled power device V 4 is used to provide a negative voltage stress output channel when the voltage of capacitor C s is negative. During the time period from the moment t Figure 4 shown to the moment t 1 , the voltage of capacitor C 2 is positive; at the moment t s , the semi-controlled power device V 2 conducts, and inductor L 3 and capacitor C 1 are in series resonance. The current of inductor L1 increases first and then decreases sinusoidally, and the voltage of capacitor C s decreases from positive to negative; at the moment t s , the current of inductor L 3 crosses zero negatively, the semi-controlled power device V 1 automatically turns off, the voltage of capacitor C 3 reaches the minimum value, and the semi-controlled power device V s conducts, and the voltage source subsystem outputs negative voltage stress; at the moment t 4 , the semi-controlled power device V 4 conducts, capacitor C 5 and inductor L s are in series resonance, the current of inductor L 2 increases first and then decreases sinusoidally, and the voltage of capacitor C 2 increases from negative to positive; at the moment t s ...5 At this moment, the semi-controlled power device V 3 The voltage source subsystem outputs positive voltage stress; at t 6 At this moment, the semi-controlled power device V 2 On, DC voltage source u DC Through the inductor L 2 is the capacitance C s Charging, capacitor C s The voltage is finally equal to the DC voltage source u DC Therefore, the voltage stress of the device under test generally presents a square wave waveform, which is consistent with Figure 2 There are significant differences in the voltage and pressure waveforms under the actual operating conditions of the converter valve shown in FIG.

[0054] Please combine Figure 3 and Figure 4 Understand, in Figure 3 In the equivalent application working condition experimental circuit of the converter valve shown in the figure, the working principle of the current source subsystem is that two groups of six-pulsation converter valves are operated in pairs to 3 A constant current is generated on Figure 4 The t shown 1 Time to t 3 During the time period of time, the device under test and the semi-controlled power device V 1 The bridge arm is in the commutation conduction period, and the inductor L 3 The current of the semi-controlled power device V 1 As an isolation valve to prevent the voltage stress output of the voltage source subsystem from affecting the operation of the current source subsystem, the semi-controlled power device V 1 With the device under test at t 1 Since the voltage level of the current source subsystem and the leakage inductance of the AC transformer are different from the actual working conditions of the converter valve, in order to achieve the equivalent di / dt of the current stress drop process, the converter valve equivalent application working condition experimental circuit is set at t 2 Time to t 3 The time period between the times needs to utilize the resonance process of the voltage source subsystem, resulting in the transient current stress waveform of the device under test during this time period (see Figure 4 ) and the transient current stress waveform in the actual operation of the converter valve (see Figure 2 ) also have significant differences.

[0055] Based on this, some embodiments of the present disclosure provide an equivalent application condition experimental circuit and an experimental method thereof, which are used to improve the equivalence of the experimental electrical stress of the device under test and the actual operating condition electrical stress, thereby improving the experimental reliability of the equivalent application condition experimental circuit and effectively reducing the reactive power generated during its operation.

[0056] In some embodiments of the present disclosure, the equivalent application condition experimental circuit includes: a device under test and a controllable power supply system. The controllable power supply system is connected to both ends of the device under test and is configured to: generate a controllable voltage stress across the device under test when the device under test is in a blocking state; and generate a controllable current stress across the device under test when the device under test is in a conducting state; wherein the waveform changes of the controllable voltage stress and the controllable current stress both conform to the waveform changes of the corresponding electrical stress of the device under test in the actual application conditions.

[0057] Herein, the waveform changes of the controllable voltage stress and the controllable current stress both conform to the waveform changes of the corresponding electrical stress of the device under test in the actual application conditions, which means that: the waveform changes of the controllable voltage stress and the controllable current stress are equivalently the same as the waveform changes of the corresponding electrical stress of the device under test in the actual application conditions, or they are similar within the target deviation range, or the waveforms of the controllable voltage stress and the controllable current stress are the accelerated degradation stress waveforms of the corresponding electrical stress of the device under test in the actual application conditions.

[0058] Exemplarily, the controllable voltage stress and the controllable current stress are the equivalent electrical stress or the accelerated degradation stress of the corresponding electrical stress of the device under test in the actual application conditions.

[0059] In the embodiments of the present disclosure, by connecting a controllable power supply system to both ends of the device under test and enabling the controllable power supply system to generate a controllable voltage stress across the device under test when the device under test is in a blocking state and generate a controllable current stress across the device under test when the device under test is in a conducting state, while ensuring that the waveform changes of the controllable voltage stress and the controllable current stress both conform to the waveform changes of the corresponding electrical stress of the device under test in the actual application conditions. In this way, the embodiments of the present disclosure can precisely regulate the output electrical signal through the controllable power supply system, thereby generating an electrical stress that is approximately completely equivalent to the actual application conditions across the device under test, thus improving the equivalence between the experimental electrical stress and the actual operating condition electrical stress of the device under test, and further effectively improving the experimental reliability of the equivalent application condition experimental circuit and effectively reducing the reactive power generated during its operation.

[0060] In some embodiments of the present disclosure, please refer to Figure 5 , the controllable power supply system includes a first programmable power supply system 1 and a second programmable power supply system 2 that are respectively connected to both ends of the device under test, and the circuit structures of the first programmable power supply system 1 and the second programmable power supply system 2 are the same.

[0061] Exemplarily, the first programmable power supply system 1 includes: a first three-phase power supply 11 and a second three-phase power supply 13 with opposite phases, a converter 14, and an inductor 15. Among them, the first three-phase power supply 11 and the second three-phase power supply 13 are connected to a common ground 12; the input ends of the converter 14 are respectively connected to the output end of the first three-phase power supply 11, the output end of the second three-phase power supply 13, and the common ground 12; one end of the inductor 15 is connected to the output end of the converter 14, and the other end is connected to the device under test. Thus, the output of the converter 14 can be used as the output of the first programmable power supply system 1 after passing through the inductor 15.

[0062] Exemplarily, the second programmable power supply system 2 includes: a first three-phase power supply 21 and a second three-phase power supply 23 with opposite phases, a converter 24, and an inductor 25. Among them, the first three-phase power supply 21 and the second three-phase power supply 23 are connected to a common ground 22; the input ends of the converter 24 are respectively connected to the output end of the first three-phase power supply 21, the output end of the second three-phase power supply 23, and the common ground 22; one end of the inductor 25 is connected to the output end of the converter 24, and the other end is connected to the device under test. Thus, the output of the converter 24 can be used as the output of the second programmable power supply system 2 after passing through the inductor 25.

[0063] In some embodiments of the present disclosure, please refer to Figure 6 , both the converter 14 and the converter 24 include: a plurality of input ends (such as IN1 to IN7), a plurality of bidirectional switch devices (such as S1 to S7), and an output end OUT. Among them, the plurality of input ends (such as IN1 to IN7) of the converter 14 are respectively connected to each phase circuit of the first three-phase power supply 11 and the second three-phase power supply 13 and the common ground 12, and one end of any bidirectional switch device is connected to the corresponding input end, and the other end is connected to the output end OUT of the converter 14. The plurality of input ends (such as IN1 to IN7) of the converter 24 are respectively connected to each phase circuit of the first three-phase power supply 21 and the second three-phase power supply 23 and the common ground 22, and one end of any bidirectional switch device is connected to the corresponding input end, and the other end is connected to the output end OUT of the converter 24.

[0064] From the above, the converters 14 and 24 are used to: in response to the switching control signals of their plurality of bidirectional switch devices (such as S1 to S7), select one input end from the plurality of input ends (such as S1 to S7) to connect to their output end OUT at the target moment for output.

[0065] In the embodiments of the present disclosure, through the cooperation of converter 14 and converter 24, voltage stress can be generated at both ends of inductor 15, the device under test, and inductor 25. Specifically, this voltage stress is: the voltage difference between the interconnection structure of the first three-phase power supply 11, the second three-phase power supply 13, and the common ground 12 and the interconnection structure of the first three-phase power supply 21, the second three-phase power supply 23, and the common ground 22. When the device under test is in the blocking state, the controllable voltage stress across the device under test is the difference between the output voltages of converter 14 and converter 24. When the device under test is in the conducting state, the difference between the output voltages of converter 14 and converter 24 can form a controllable current stress through inductor 15 and inductor 25. Thus, the first programmable power supply system 1 and the second programmable power supply system 2 provided in the embodiments of the present disclosure can cooperate with each other to ultimately generate electrical stress on the device under test that is equivalent to or accelerates the degradation of the actual application conditions of the device under test.

[0066] It should be added that, in some embodiments, the controllable current stress across the device under test is related to the total inductance value of inductor 15 and inductor 25, and can be specifically realized by selecting the inductance value of a single inductor 15 or a single inductor 25. In some embodiments, the implementation manners of the above-mentioned three-phase power supplies include but are not limited to: complete sets of power supplies, grid simulators, DC-AC converters, or transformers, etc. In some embodiments, the device under test includes but is not limited to converter valve group components or power semiconductor devices, and can also be, for example, other component elements in the converter valve group components.

[0067] In addition, it can be understood that the bidirectional switch devices (such as S1 to S7) in the above-mentioned converter 14 and converter 24 have bidirectional voltage blocking and bidirectional current control capabilities, and there can be various different implementation manners specifically.

[0068] In some embodiments, the bidirectional switch devices in converter 14 and converter 24 can be directly or indirectly implemented by using power semiconductor devices, relays, contactors, and other electronic components. Power semiconductor devices include but are not limited to intrinsic bidirectional power semiconductor devices.

[0069] Please refer to Figure 7 , and the following embodiments of the present disclosure also exemplarily give some possible implementation manners of the bidirectional switch device, but are not limited thereto.

[0070] Embodiment 1, as shown in FIG. (a) in Figure 7 , the bidirectional switch device includes a first bidirectional switch unit U1. The first bidirectional switch unit U1 includes: a diode D full bridge and a transistor T connected in parallel to the DC side of the diode D full bridge. The AC side of the diode D full bridge is connected to the corresponding input terminal, which is the interface terminal of the bidirectional switch device.

[0071] Embodiment 2, as in Figure 7As shown in Figure (b) therein, the bidirectional switch device includes: at least two stages of first bidirectional switch units U1 connected in series in sequence; wherein, the non-series AC sides of the first stage and the last stage of the diode D full bridge are connected to the corresponding input terminals, which are the interface terminals of the bidirectional switch device.

[0072] Embodiment 3, as Figure 7 As shown in Figure (c) therein, the bidirectional switch device includes a second bidirectional switch unit U2. The second bidirectional switch unit U2 includes: a diode group full bridge and a transistor group connected in parallel to the DC side of the diode group full bridge; wherein, the bridge arms of the diode group full bridge include at least two stages of diodes D connected in series in sequence; the transistor group includes at least two stages of transistors T connected in series in sequence.

[0073] Embodiment 4, as Figure 7 As shown in Figure (d) therein, the bidirectional switch device includes: at least two stages of second bidirectional switch units U2 connected in series in sequence; wherein, the non-series AC sides of the diode group full bridges of the first stage and the last stage of the second bidirectional switch unit U2 are connected to the corresponding input terminals, which are the interface terminals of the bidirectional switch device.

[0074] Embodiment 5, as Figure 7 As shown in Figure (e) therein, the bidirectional switch device includes a third bidirectional switch unit U3. The third bidirectional switch unit U3 includes: a first transistor T1 and a second transistor T2 connected in reverse series, the first transistor T1 is used to block the forward voltage and control the forward current, and the second transistor T2 is used to block the reverse voltage and control the reverse current.

[0075] Embodiment 6, as Figure 7 As shown in Figure (f) therein, the bidirectional switch device includes: at least two stages of third bidirectional switch units U3 connected in series in sequence.

[0076] Embodiment 7, as Figure 7 As shown in Figure (g) therein, the bidirectional switch device includes a fourth bidirectional switch unit U4. The fourth bidirectional switch unit U4 includes: a first transistor group and a second transistor group connected in reverse series; the first transistor group is used to block the forward voltage and control the forward current, and includes at least two stages of first transistors T1 connected in series in sequence; the second transistor group is used to block the reverse voltage and control the reverse current, and includes at least two stages of second transistors T2 connected in series in sequence.

[0077] Embodiment 8, as Figure 7 As shown in Figure (h) therein, the bidirectional switch device includes: at least two stages of fourth bidirectional switch units U4 connected in series in sequence.

[0078] It should be noted that the transistor T in some of the above embodiments includes, but is not limited to, a metal oxide semiconductor field effect transistor (MOSFET for short). Moreover, the transistor T has a parasitic anti-parallel diode D, which can only block the forward voltage and cannot block the reverse voltage, that is, its forward current is controllable and the reverse current is uncontrollable. It belongs to a reverse-conducting power semiconductor device and can be replaced by a parallel circuit formed by anti-parallel connection of at least one transistor device among an insulated gate bipolar transistor (IGBT for short), an integrated gate-commutated thyristor (IGCT for short), a field effect transistor (FET for short), or a high electron mobility transistor (HEMT for short) and the diode D. Moreover, the transistor devices can be connected in parallel to further increase the current control ability.

[0079] In addition, if the transistor T is connected in series with the diode D, it can block both the forward voltage and the reverse voltage, but it can also only control the unidirectional current. It is a reverse-blocking power semiconductor device and can be replaced by an intrinsic reverse-blocking power semiconductor device or a series circuit formed by series connection of at least one transistor device among IGBT, IGCT, or HEMT and the diode D. Similarly, the transistor devices can be connected in parallel to further increase the current control ability.

[0080] Embodiment Nine, as shown in Figure 7 Figure (i) of [description reference], the bidirectional switch device includes: a fifth bidirectional switch unit U5. The fifth bidirectional switch unit includes two reverse-blocking power semiconductor devices connected in anti-parallel, or two series modules M connected in anti-parallel; wherein, the series module M is formed by series connection of at least one of an insulated gate bipolar transistor (IGBT for short), an integrated gate-commutated thyristor (IGCT for short), or a high electron mobility transistor (HEMT for short) and a diode; one series module M is used to control the forward current, and the other series module M is used to control the reverse current.

[0081] Embodiment Ten, as shown in Figure 7As shown in Figure (j), the bidirectional switch device includes at least two stages of fifth bidirectional switch units U5 connected in series in sequence.

[0082] Embodiment XI, as Figure 7 As shown in Figure (k), the bidirectional switch device includes a sixth bidirectional switch unit U6. The sixth bidirectional switch unit includes two series module groups connected in reverse parallel; wherein, each series module group includes at least two stages of series modules M connected in series in sequence; one series module group is used to control the forward current, and the other series module group is used to control the reverse current. And, the aforementioned two series module groups can both block bidirectional voltage.

[0083] Embodiment XII, as Figure 7 As shown in Figure (l), the bidirectional switch device includes at least two stages of sixth bidirectional switch units U6 connected in series in sequence.

[0084] Thus, the equivalent application condition experiment circuit provided by the embodiments of the present disclosure also has a relatively high degree of modularity, and it is easy to increase the experimental stress by increasing the number of modules, so that it can have elastic experimental capabilities to enhance the experimental diversity of the equivalent application condition experiment circuit.

[0085] It is worth supplementing that in some other embodiments of the present disclosure, the controllable power supply system can also have other different implementation manners. For example, the circuit structures in the first programmable power supply system and the second programmable power supply system can be simplified to obtain a more convenient-to-implement controllable power supply system.

[0086] Please refer to Figure 8 , in the embodiments of the present disclosure, the controllable power supply system includes: a first three-phase power supply 11, a transformer 16, a first converter (i.e., converter 14), and a second converter (i.e., converter 24). The transformer 16 is connected to the first three-phase power supply 11 and is connected to the common ground 12. The input end of the first converter (i.e., converter 14) is connected to the transformer 16 and the common ground 12, and its output end is connected to one end of the device under test through an inductor 15. The input end of the second converter (i.e., converter 24) is connected in parallel with the first converter (i.e., converter 14) and is connected to the transformer 16 and the common ground 12, and its output end is directly connected to the other end of the device under test.

[0087] Exemplarily, the transformer 16 includes but is not limited to a DYY type transformer.

[0088] Some embodiments of the present disclosure also provide an experimental method for an equivalent application condition experiment circuit, which is used to perform an equivalent application condition experiment on the equivalent application condition experiment circuit described in the above embodiments. Please refer to Figure 9 , the experimental method includes the following steps S100 and S200.

[0089] S100. When the device under test is in the blocking state, the controllable power supply system generates a controllable voltage stress across the two ends of the device under test.

[0090] S200. When the device under test is in the conducting state, the controllable power supply system generates a controllable current stress across the two ends of the device under test.

[0091] Here, the waveform changes of both the controllable voltage stress and the controllable current stress conform to the waveform changes of the corresponding electrical stress of the device under test in the actual application working conditions.

[0092] In some embodiments of the present disclosure, the controllable power supply system includes two converters respectively connected to the device under test, and at least one converter is connected to the device under test through an inductor. The experimental method further includes: when the device under test is in the blocking state, selecting and turning on the target input terminal in each converter so that the voltage difference between the output terminals of the two converters generates a controllable voltage stress across the device under test; when the device under test is in the conducting state, selecting and turning on the target input terminal in each converter so that the voltage difference between the output terminals of the two converters generates a controllable current stress across the device under test through the inductor.

[0093] Here, the structure of the converter can refer to the relevant records in the foregoing some embodiments. Correspondingly, when the device under test is in the blocking state or the conducting state, the equivalent application working condition requirements can be matched, and an input terminal is selected from multiple input terminals of each converter as the target input terminal and the corresponding circuit is turned on to obtain the required controllable voltage stress or controllable current stress. That is, at the same moment, the target input terminals of the two converters are respectively used to connect the same or different objects, and the object includes a common ground or different phase circuits.

[0094] The present disclosure embodiments do not limit the selection rule of the input terminal in the converter, as long as it can meet the experimental requirements of the corresponding equivalent application working conditions. And, the selection rule of the input terminal in each converter can be pre-programmed into the corresponding controllable power supply system after the matching requirements are set. Although the control part of the controllable power supply system is not described in the embodiments of the present disclosure, it can be understood that the control part of the controllable power supply system can have a programming function to perform control implementation according to the program.

[0095] It should be understood that although the steps in the flowcharts involved in the above-described embodiments are shown in sequence according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless there is a clear description in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-described embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily executed at the same moment, but can be executed at different moments. The execution order of these steps or stages is not necessarily sequential, but can be executed alternately or in turn with at least a part of other steps or steps or stages in other steps.

[0096] To more clearly illustrate the experimental method of the equivalent application condition experimental circuit provided by the embodiments of the present disclosure, in the following some embodiments, Figure 8 the shown controllable power supply system and Figure 7 the bidirectional switch device shown in FIG. (b) in

[0097] are taken as examples to illustrate the experimental method of the equivalent application condition experimental circuit. Figure 1 in T 1 the actual application conditions of the bridge arm are used. Thus, the experimental method of the equivalent application condition experimental circuit can be executed as follows:

[0098] At time t 1 , the device under test is triggered to conduct. The input end of the converter 14 is connected to the common ground 12 through the bidirectional switch device, and the input end of the converter 24 is connected to the C phase of the positive three-phase power supply through the bidirectional switch device. The voltage difference between the output ends of the converter 14 and the converter 24 can generate an increasing controllable current stress on the device under test through the inductor 15.

[0099] At time t 2 , the input ends of the converter 14 and the converter 24 are respectively connected to the public ground 12 through the bidirectional switch device, and the inductor 15 can conduct continuous current through the loop. At this time, the controllable current stress of the device under test approximately remains unchanged.

[0100] At time t 3At this moment, the device under test is triggered to conduct. The input end of converter 14 is connected to the common ground 12 through a bidirectional switch device, and the input end of converter 24 is connected to phase A of the negative three-phase power supply through a bidirectional switch device. The voltage difference between the output ends of converter 14 and converter 24 can generate a decreasing controllable current stress on the device under test through inductor 15.

[0101] At t 4 At this moment, the current stress of the device under test crosses zero negatively, and the device under test resumes the blocking state. The input end of converter 14 is connected to phase A of the positive three-phase power supply through a bidirectional switch device, and the input end of converter 24 is connected to phase A of the negative three-phase power supply through a bidirectional switch device. The voltage difference between the output ends of converter 14 and converter 24 generates a controllable voltage stress on the device under test.

[0102] At t 6 At this moment, the current stress of the device under test crosses zero negatively, and the device under test resumes the blocking state. The input end of converter 14 is connected to phase A of the positive three-phase power supply through a bidirectional switch device, and the input end of converter 24 is connected to phase B of the positive three-phase power supply through a bidirectional switch device. The voltage difference between the output ends of converter 14 and converter 24 generates a controllable voltage stress on the device under test.

[0103] At t 7 At this moment, the current stress of the device under test crosses zero negatively, and the device under test resumes the blocking state. The input end of converter 14 is connected to phase A of the positive three-phase power supply through a bidirectional switch device, and the input end of converter 24 is connected to phase A of the negative three-phase power supply through a bidirectional switch device. The voltage difference between the output ends of converter 14 and converter 24 generates a controllable voltage stress on the device under test.

[0104] At t 8 At this moment, the current stress of the device under test crosses zero negatively, and the device under test resumes the blocking state. The input port of converter 14 is connected to phase A of the positive three-phase power supply through a bidirectional switch device, and the input end of converter 24 is connected to phase C of the positive three-phase power supply through a bidirectional switch device. The voltage difference between the output ends of converter 14 and converter 24 generates a controllable voltage stress on the device under test.

[0105] At t 9 At this moment, the current stress of the device under test crosses zero negatively, and the device under test resumes the blocking state. The input end of converter 14 is connected to phase C of the negative three-phase power supply through a bidirectional switch device, and the input end of converter 24 is connected to phase C of the positive three-phase power supply through a bidirectional switch device. The voltage difference between the output ends of converter 14 and converter 24 generates a controllable voltage stress on the device under test.

[0106] At t 10At this moment, the current stress of the device under test crosses zero negatively, and the device under test resumes the blocking state. The input end of converter 14 is connected to phase B of the positive three-phase power supply through a bidirectional switching device, and the input end of converter 24 is connected to phase C of the positive three-phase power supply through a bidirectional switching device. The voltage difference between the output ends of converter 14 and converter 24 generates a controllable voltage stress on the device under test.

[0107] At time t 11 At this moment, the current stress of the device under test crosses zero negatively, and the device under test resumes the blocking state. The input end of converter 14 is connected to phase C of the negative three-phase power supply through a bidirectional switching device, and the input end of converter 24 is connected to phase C of the positive three-phase power supply through a bidirectional switching device. The voltage difference between the output ends of converter 14 and converter 24 generates a controllable voltage stress on the device under test and is ready to enter the next cycle.

[0108] As described above, the electrical stress waveform diagram that can be obtained by the experimental method of the equivalent application condition experimental circuit provided by the embodiments of the present disclosure is as Figure 10 shown. After comparison Figure 2 and Figure 10 it can be seen that the experimental method of the equivalent application condition experimental circuit provided by the embodiments of the present disclosure can obtain experimental electrical stresses (including voltage stress and current stress) that are approximately completely equivalent to the electrical stresses of the device under test in the actual application conditions.

[0109] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features of the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0110] The above-described embodiments only represent several implementation manners of the present disclosure, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present disclosure, several modifications and improvements can be made, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the patent of the present disclosure should be subject to the appended claims.

Claims

1. An equivalent application working condition experimental circuit, characterized in that: include: Device under test; A controllable power supply system is connected to both ends of the device under test and is configured to: generate controllable voltage stress at both ends of the device under test when the device under test is in a blocking state; and generate controllable current stress at both ends of the device under test when the device under test is in a conducting state; wherein the waveform changes of the controllable voltage stress and the controllable current stress both conform to the waveform changes of the corresponding electrical stress of the device under test in actual application conditions; Wherein, the controllable power supply system comprises a first programmable power supply system and a second programmable power supply system respectively connected to two ends of the device under test, and the circuit structure of the first programmable power supply system and the second programmable power supply system are the same; The first programmable power supply system and the second programmable power supply system both include: A first three-phase power supply and a second three-phase power supply having opposite phases, wherein the first three-phase power supply and the second three-phase power supply are connected to a common ground; A converter, wherein the input end of the converter is respectively connected to the output end of the first three-phase power supply, the output end of the second three-phase power supply and the common ground; An inductor, one end of which is connected to the output end of the converter, and the other end of which is connected to the device under test.

2. The equivalent application working condition experimental circuit according to claim 1 is characterized in that: The converter comprises: a plurality of input terminals, a plurality of bidirectional switch devices and an output terminal; The plurality of input terminals are respectively connected to the respective phase circuits of the first three-phase power supply and the second three-phase power supply and the common ground; A plurality of bidirectional switch devices correspond one to one with the plurality of input terminals; and one end of any of the bidirectional switch devices is connected to the input terminal, and the other end is connected to the output terminal; Wherein, the converter is used to: respond to the switch control signal of each of the bidirectional switch devices, and select one of the input terminals from the multiple input terminals to connect to the output terminal at a target time.

3. The equivalent application working condition experimental circuit according to claim 2 is characterized in that: The implementation of the bidirectional switch device includes any one of the following: In the first embodiment, the bidirectional switch device comprises a first bidirectional switch unit; the first bidirectional switch unit comprises: a diode full bridge and a transistor connected in parallel to the DC side of the diode full bridge, and the AC side of the diode full bridge is connected to the corresponding input terminal; In a second embodiment, the bidirectional switch device comprises: at least two stages of the first bidirectional switch units connected in series in sequence; wherein the non-series AC sides of the first and last stages of the diode full bridges are connected to the corresponding input terminals; Embodiment 3, the bidirectional switch device includes a second bidirectional switch unit; the second bidirectional switch unit includes: a diode group full bridge and a transistor group connected in parallel to the DC side of the diode group full bridge; wherein the bridge arm of the diode group full bridge includes at least two stages of diodes connected in series in sequence; the transistor group includes at least two stages of transistors connected in series in sequence; In a fourth embodiment, the bidirectional switch device comprises: at least two stages of the second bidirectional switch units connected in series in sequence; wherein the non-series AC sides of the diode group full bridges in the first and last stages of the second bidirectional switch units are connected to the corresponding input terminals; In a fifth embodiment, the bidirectional switch device includes a third bidirectional switch unit; the third bidirectional switch unit includes: a first transistor and a second transistor connected in reverse series, the first transistor is used to block a forward voltage and control a forward current, and the second transistor is used to block a reverse voltage and control a reverse current; In a sixth embodiment, the bidirectional switch device comprises: at least two stages of the third bidirectional switch units connected in series in sequence; Embodiment 7, the bidirectional switch device includes a fourth bidirectional switch unit; the fourth bidirectional switch unit includes: a first transistor group and a second transistor group connected in series in reverse order; the first transistor group is used to block the forward voltage and control the forward current, including at least two first transistors connected in series in sequence; the second transistor group is used to block the reverse voltage and control the reverse current, including at least two second transistors connected in series in sequence; In an eighth embodiment, the bidirectional switch device comprises: at least two stages of the fourth bidirectional switch units connected in series in sequence; Embodiment 9, the bidirectional switch device comprises: a fifth bidirectional switch unit; the fifth bidirectional switch unit comprises two reverse-resistance power semiconductor devices connected in reverse parallel, or two series modules connected in reverse parallel; wherein the series module is formed by at least one of an insulated gate bipolar transistor, an integrated gate-commutated thyristor, a field effect transistor or a high electron mobility transistor connected in series with a diode; one of the series modules is used to control the forward current, and the other series module is used to control the reverse current; In a tenth embodiment, the bidirectional switch device comprises: at least two stages of the fifth bidirectional switch units connected in series in sequence; Embodiment 11, the bidirectional switch device comprises: a sixth bidirectional switch unit; the sixth bidirectional switch unit comprises two series module groups connected in reverse parallel; wherein the series module group comprises at least two stages of series modules connected in series in sequence; one of the series module groups is used to control the forward current, and the other series module group is used to control the reverse current; In a twelfth embodiment, the bidirectional switch device comprises: at least two stages of the sixth bidirectional switch units connected in series in sequence.

4. The equivalent application working condition experimental circuit according to any one of claims 1 to 3, characterized in that: The device to be tested includes: a converter valve group component or a power semiconductor device.

5. An experimental method for an equivalent application working condition experimental circuit, characterized in that: Applicable to the equivalent application working condition experimental circuit according to any one of claims 1 to 4, the experimental method comprises: When the device under test is in a blocking state, the controllable power supply system generates the controllable voltage stress at two ends of the device under test; When the device under test is in a conducting state, the controllable power supply system generates the controllable current stress at two ends of the device under test; The waveform changes of the controllable voltage stress and the controllable current stress are consistent with the waveform changes of the corresponding electrical stress of the device under test in actual application conditions; Wherein, the controllable power supply system includes two converters respectively connected to the device under test, and at least one of the converters is connected to the device under test through an inductor; the experimental method also includes: When the device under test is in a blocking state, selectively connecting a target input terminal in each of the converters so that a voltage difference between output terminals of two converters generates the controllable voltage stress on the device under test; When the device under test is in the on state, the target input terminal of each converter is selectively connected, so that the voltage difference between the output terminals of two converters generates the controllable current stress on the device under test through the inductor.

Images