Continuous current pulse generation circuit for power device test and control method thereof

Abstract

The invention discloses a continuous current pulse generation circuit for power device testing and a control method thereof, and relates to the technical field of power electronics, the continuous current pulse generation circuit comprises a power supply, a control unit, a switch unit, an energy storage unit, an inductive load and a current absorption unit; the switch unit comprises a first relay, a second relay, a third relay, n first switches and one second switch; the energy storage unit comprises n capacitors; the control unit is used for respectively controlling the on-off of the first relay, the second relay, the third relay, the n first switches and the n second switches, carrying out different-stage control on each capacitor, and providing continuous current pulse for the test of the power device; the different stages comprise a capacitor charging stage, a capacitor discharging stage according to a time sequence and a capacitor residual charge releasing stage. According to the invention, more real continuous current pulse can be provided for the power device, and the reliability test requirement of the device under the impact of the continuous current pulse is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power electronics, and particularly relates to a continuous current pulse generation circuit for power device testing and a control method thereof. BACKGROUND

[0002] High-voltage and high-power power electronic devices, such as insulated gate bipolar transistors (IGBTs) and the like, are widely used in high-voltage direct current transmission, rail transit, electric locomotive, new energy power generation (such as wind power and photovoltaic power), variable frequency speed regulation and other key occasions. As the core components of energy conversion and control, these power devices often face complex and severe electrical environments during operation, such as system short circuit, power grid mutation, lightning disturbance or load mutation, etc. These working conditions may cause the power device to withstand a current much higher than the rated value in a short time. If the power device fails under such impact, it may cause system malfunction, equipment damage and safety accidents.

[0003] In order to ensure the electrical reliability and safety of the power device under the above extreme working conditions, it is necessary to deeply explore the characteristics of the power device under the large current stress. The current mainstream testing scheme usually adopts a large-capacity capacitor and an electric reactor in series to form a single current pulse in the load loop, which is used to simulate transient large current impact. The advantage of this scheme is that the circuit structure is simple and the construction cost is low, but it has obvious limitations - it can only generate a single pulse and cannot reflect the characteristics of the power device under continuous multiple large current impacts in a short time.

[0004] However, in actual engineering applications, power devices often face continuous large current impact conditions, such as current fluctuations caused by frequent changes in traction load, periodic impacts caused by system harmonic disturbances, or repeated short circuits caused by inverter out of control. The cumulative effect of continuous large current impact may more easily cause the device junction temperature to rise, local parasitic oscillation, and even induce premature failure. Therefore, it is difficult to fully evaluate the stability and reliability of the device in the real use environment by relying on single current pulse testing scheme. SUMMARY

[0005] The purpose of the present application is to provide a continuous current pulse generation circuit for power device testing and a control method thereof, to provide more realistic continuous current pulse impact simulation conditions for power devices, and to meet the reliability testing requirements of the device under continuous current pulse impact.

[0006] To achieve the above purpose, the present application provides the following scheme:

[0007] The first aspect of the present application provides a continuous current pulse generation circuit for power device testing, comprising: a power supply, a control unit, a switching unit, an energy storage unit, an inductive load and a current absorption unit;

[0008] The switching unit comprises: a first relay, a second relay, a third relay, n first switches and one second switch; the energy storage unit comprises: n capacitors;

[0009] The i-th capacitor is connected in series with the i-th first switch to form an i-th series structure; n>1; 1≤i≤n;

[0010] The first relay, the second relay, the third relay, each of the first switches and the second switch are connected with the control unit respectively;

[0011] One end of the first relay is connected with the positive pole of the power supply, and the other end of the first relay is connected with one end of each series structure, one end of the second relay and one end of the third relay respectively; the other end of the third relay is connected with one end of the inductive load, and the other end of the inductive load is connected with one end of the power device and one end of the current absorption unit respectively; the other end of the power device is connected with one end of the second switch;

[0012] The negative pole of the power supply, the other end of each series structure, the other end of the second relay, the other end of the second switch and the other end of the current absorption unit are grounded;

[0013] The control unit is used to control the on-off of the first relay, the second relay, the third relay, n first switches and the second switch respectively, to control the capacitors in different stages, and to provide continuous current pulses for the testing of the power device; the different stages include: capacitor charging stage, capacitor discharging stage according to time sequence and capacitor residual charge release stage.

[0014] In an embodiment, the continuous current pulse generation circuit for power device testing further comprises: a first protection resistor and a second protection resistor;

[0015] One end of the first relay is connected with the positive pole of the power supply through the first protection resistor;

[0016] The other end of the second switch is grounded through the second protection resistor.

[0017] In an embodiment, the continuous current pulse generation circuit for power device testing further comprises: an isolation unit; the isolation unit comprises: n isolation diodes;

[0018] One end of the jth isolation diode is connected with one end of the jth first switch, and the other end of the jth isolation diode is connected with one end of the (j+1)th first switch, 1≤j≤n-1;

[0019] One end of the nth isolation diode is connected with one end of the nth first switch, and the other end of the nth isolation diode is connected with one end of the second relay and one end of the third relay respectively.

[0020] In an embodiment, the current absorption unit comprises a diode, a capacitor, a resistor and a metal oxide surge arrester.

[0021] One end of the diode is connected with the other end of the inductive load, one end of the power device and one end of the metal oxide surge arrester respectively, and the other end of the diode is connected with one end of the capacitor and one end of the resistor respectively.

[0022] The other end of the capacitor, the other end of the resistor and the other end of the metal oxide surge arrester are all grounded.

[0023] In an embodiment, the control unit is a computer or an embedded controller.

[0024] In an embodiment, the power supply is a high-voltage direct-current power supply.

[0025] In an embodiment, each of the first switch and the second switch is a high-voltage IGBT switch.

[0026] In a second aspect, the application provides a control method of a continuous current pulse generation circuit for power device testing, for controlling the continuous current pulse generation circuit for power device testing described above, the control method of the continuous current pulse generation circuit for power device testing comprising:

[0027] In the capacitor charging phase, the control unit controls the first relay to be closed, the second relay and the third relay to be opened, and the n first switches and the second switch to be kept in the off state, and the power supply forms a charging path through the n first switches to charge the n capacitors in parallel, and when the voltage of each capacitor reaches the voltage output by the power supply, the control unit controls the first relay to be opened, and the capacitor charging phase is ended.

[0028] In the capacitor discharging phase in time sequence, the control unit controls the first relay and the second relay to be disconnected, and the third relay to be closed, and based on the preset number of required continuous current pulses, every preset time interval, the control unit controls the preset number of capacitors to discharge in time sequence, starting from the first switch; the discharge process of the i-th capacitor includes: the control unit controls the i-th first switch to be turned on, forming a current pulse circulation path in the order of the i-th capacitor→the i-th first switch→the third relay→the inductive load→the second switch→the ground, after the preset on time of the second switch, the control unit controls the second switch to be actively turned off, the large current is transferred to the current absorption unit, current absorption is realized, and the discharge of the i-th capacitor is completed.

[0029] In the capacitor residual charge release phase, under the condition that the preset residual charge release time is met, the control unit controls the first relay and the third relay to be disconnected, and the second relay to be closed, and the residual charge of the n capacitors is released.

[0030] In an embodiment, the calculation formula of the charging time of the capacitor charging phase is:

[0031]

[0032] Wherein, T C is the charging time of the capacitor charging phase; n is the number of capacitors; C is the capacitance value of each capacitor; U0 is the output voltage of the power supply; I is the output current of the power supply.

[0033] In an embodiment, the calculation formula of the preset residual charge release time is:

[0034] T d = 5CR2;

[0035] Wherein, T d is the preset residual charge release time; R2 is the resistance value of the second protective resistor.

[0036] According to the specific embodiments provided in the application, the following technical effects are disclosed:

[0037] This application discloses a continuous current pulse generating circuit and its control method for power device testing. The continuous current pulse generating circuit for power device testing includes: a power supply, a control unit, a switching unit, an energy storage unit, an inductive load, and a current absorption unit. The switching unit includes: a first relay, a second relay, a third relay, n first switches, and one second switch. The energy storage unit includes: n capacitors; the i-th capacitor is connected in series with the i-th first switch to form the i-th series structure; n>1; 1≤i≤n; the first relay, the second relay, the third relay, each first switch, and the second switch are respectively connected to the control unit; one end of the first relay is connected to the positive terminal of the power supply, and the other end of the first relay is connected to one end of each series structure, one end of the second relay, and the third relay. One end of the device is connected; the other end of the third relay is connected to one end of the inductive load, the other end of the inductive load is connected to one end of the power device and one end of the current absorption unit, and the other end of the power device is connected to one end of the second switch; the negative terminal of the power supply, the other end of each series structure, the other end of the second relay, the other end of the second switch, and the other end of the current absorption unit are all grounded; this application controls the on / off state of the first relay, the second relay, the third relay, n first switches and second switches respectively through the control unit, and controls each capacitor at different stages to provide continuous current pulses for the testing of the power device, which can provide more realistic continuous current pulse impact simulation conditions for the power device, meet the reliability testing requirements of the device under continuous current pulse impact, and thus improve its engineering applicability. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of a continuous current pulse generation circuit for power device testing provided in one embodiment of this application;

[0040] Figure 2 This is a schematic diagram of the control method architecture for a continuous current pulse generation circuit for power device testing provided in one embodiment of this application;

[0041] Figure 3 Timing diagram for capacitor charging stage control;

[0042] Figure 4 A timing diagram for controlling the capacitor's discharge stages according to the time sequence;

[0043] Figure 5Timing diagram for capacitor residual charge release phase control;

[0044] Figure 6 Voltage curve of capacitor during capacitor charging phase;

[0045] Figure 7 Current curve of capacitor during capacitor charging phase;

[0046] Figure 8 Circuit simulation result diagram for capacitor discharging phase in sequence.

[0047] Reference signs:

[0048] Power supply - DC, inductive load - L, first relay - K1, second relay - K2, third relay - K3, first switch - T1, T2,..., Tn, second switch - T0, capacitor - C1, C2,..., Cn, first protection resistor - R1, second protection resistor - R2, isolation diode - D1, D2,..., Dn, diode - Cs, capacitor - Cs, resistor - Rs, metal oxide surge arrester - MOV. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all 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 the present application.

[0050] The purpose of the present application is to provide a continuous current pulse generation circuit for power device testing and a control method thereof, aiming to provide more real continuous current pulse impact simulation conditions for power devices, meet the reliability test requirements of the devices under continuous current pulse impact, and improve their engineering applicability.

[0051] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0052] In an exemplary embodiment, as shown in Figure 1 A continuous current pulse generation circuit for power device testing is provided, which includes a power supply DC, a control unit, a switch unit, an energy storage unit, an inductive load L and a current absorption unit.

[0053] The switch unit comprises a first relay K1, a second relay K2, a third relay K3, n first switches (T1, T2, …, Tn) and a second switch T0; and the energy storage unit comprises n capacitors (C1, C2, …, Cn).

[0054] The i-th capacitor is connected in series with the i-th first switch to form an i-th series structure; n>1; 1≤i≤n.

[0055] The first relay K1, the second relay K2, the third relay K3, each first switch and the second switch T0 are connected with the control unit.

[0056] One end of the first relay K1 is connected with the positive pole of the power supply DC, and the other end of the first relay K1 is connected with one end of each series structure, one end of the second relay K2 and one end of the third relay K3 respectively; the other end of the third relay K3 is connected with one end of the inductive load L, and the other end of the inductive load L is connected with one end of the power device and one end of the current absorption unit respectively, and the other end of the power device is connected with one end of the second switch T0.

[0057] The negative pole of the power supply DC, the other end of each series structure, the other end of the second relay K2, the other end of the second switch T0 and the other end of the current absorption unit are grounded.

[0058] The control unit is used to control the on-off of the first relay, the second relay, the third relay, n first switches and the second switch respectively, to control each capacitor in different stages, to provide continuous current pulses for the test of the power device, and the different stages include: capacitor charging stage, capacitor discharging stage according to time sequence and capacitor residual charge release stage.

[0059] As an optional implementation, the continuous current pulse generation circuit for power device test further comprises a first protection resistor R1 and a second protection resistor R2.

[0060] One end of the first relay K1 is connected with the positive pole of the power supply DC through the first protection resistor R1.

[0061] The other end of the second switch T0 is grounded through the second protection resistor R2.

[0062] The first protection resistor R1 is used to protect the high-voltage direct-current power supply, and the first protection resistor R1 is connected in series with the capacitors for voltage division, so the resistance value of the first protection resistor R1 cannot be too large.

[0063] As an optional implementation, the continuous current pulse generation circuit for power device test further comprises an isolation unit; the isolation unit comprises n isolation diodes (D1, D2, …, Dn).

[0064] One end of the jth isolation diode is connected to one end of the jth first switch, and the other end of the jth isolation diode is connected to one end of the (j+1)th first switch, 1≤j≤n-1.

[0065] One end of the nth isolation diode is connected to one end of the nth first switch, and the other end of the nth isolation diode is connected to one end of the second relay K2 and one end of the third relay K3.

[0066] As an optional embodiment, the current absorption unit comprises a diode Cs, a capacitor Cs, a resistor Rs and a metal oxide surge arrester MOV.

[0067] One end of the diode Cs is connected to the other end of the inductive load L, one end of the power device and one end of the metal oxide surge arrester MOV, respectively, and the other end of the diode Cs is connected to one end of the capacitor Cs and one end of the resistor Rs, respectively.

[0068] The other end of the capacitor Cs, the other end of the resistor Rs and the other end of the metal oxide surge arrester MOV are all grounded.

[0069] As an optional embodiment, the control unit is a computer or an embedded controller.

[0070] As an optional embodiment, the power supply DC is a high-voltage direct-current power supply.

[0071] As an optional embodiment, each of the first switch and the second switch is a high-voltage IGBT switch.

[0072] In an exemplary embodiment, as shown in Figure 2 A control method for the continuous current pulse generation circuit for power device testing is also provided, for controlling the continuous current pulse generation circuit for power device testing, the control method for the continuous current pulse generation circuit for power device testing comprising:

[0073] In the capacitor charging phase, the control unit controls the first relay to be closed, the second relay and the third relay to be opened, and the n first switches and the second switches to be kept in the off state, and the power supply forms a charging path through the n first switches to charge the n capacitors in parallel. When the voltage of each capacitor reaches the voltage output by the power supply, the control unit controls the first relay to be opened, ending the capacitor charging phase.

[0074] Specifically, the control unit controls K1 to be closed, K2 and K3 to be opened, and all high-voltage IGBT switches T0-Tn to be kept in the off state. The high-voltage direct-current power supply DC forms a charging path through the isolation diodes D1-Dn and the antiparallel diodes of the first switches T1-Tn to charge the n capacitors C1-Cn in parallel.

[0075] The high-voltage DC power supply needs to be a constant voltage and constant current source, meaning the output voltage and current of the high-voltage DC power supply remain constant. When such a high-voltage DC power supply charges the capacitors, the capacitor voltage rises linearly. Charging ends when the capacitor voltage reaches the output voltage U0 of the high-voltage DC power supply. The first protective resistor R1 in the charging circuit is used to protect the high-voltage DC power supply. R1 is connected in series with the capacitors to divide the voltage; therefore, the resistance of R1 cannot be too large. When the voltages of all n capacitors C1 to Cn reach the output voltage U0, control K1 is disconnected, completing the capacitor charging stage. Capacitors C1 to Cn are connected in parallel in pairs, thus ensuring voltage balance among them.

[0076] The control timing diagrams for each relay (K1~K3) and each high-voltage IGBT switch (T0~Tn) during the capacitor charging stage are as follows: Figure 3 As shown, T C The charging time for capacitors C1 to Cn.

[0077] As an optional implementation, the formula for calculating the charging time during the capacitor charging phase is:

[0078]

[0079] Among them, T C The charging time during the capacitor charging phase; n is the number of capacitors; C is the capacitance value of each capacitor. To ensure the consistency of all current pulses, the capacitance value of all capacitors is C; U0 is the output voltage of the power supply; I is the output current of the power supply.

[0080] Specifically, the larger the capacitance C of each capacitor and the output voltage U0 of the power supply, the longer the charging time T. C The longer the charging time, the greater the output current I of the power supply, and the longer the charging time T. C The shorter the pulse, the better. Adjusting the output voltage U0 of the power supply can adjust the amplitude I of the current pulse. off The relationship between the two is:

[0081]

[0082] Where L1 is the inductance value of the inductive load; t on The conduction time of the second switch T0.

[0083] In the capacitor discharging phase in time sequence, the control unit controls the first relay and the second relay to be disconnected, and the third relay to be closed. Based on the preset number of required continuous current pulses, the control unit controls the preset number of capacitors to discharge in time sequence every preset time interval, starting from the first switch. The discharge process of the i-th capacitor includes: the control unit controls the i-th first switch to be turned on, forming a current pulse circulation path in the order of the i-th capacitor→the i-th first switch→the third relay→the inductor load→the second switch→the ground. After the preset conduction time of the second switch, the control unit controls the second switch to be actively turned off, and the large current is transferred to the current absorption unit to realize current absorption, and the discharge of the i-th capacitor is completed.

[0084] Specifically, in the capacitor discharging phase in time sequence, the control unit controls K1 and K2 to be disconnected, K3 to be closed, and all high-voltage IGBT switches T0-Tn to be initially turned off. First, it is confirmed that the preset number of required continuous current pulses is m (1≤m≤n) (n capacitors are uniformly charged, but the experimenter may not need n continuous current pulses, so the preset number of continuous current pulses required by the experimenter needs to be determined as m, which determines the control mode later). Then every time interval Δt, the control unit triggers the high-voltage IGBT switches Ti (i=1-m) to be turned on in turn, forming a current pulse circulation path in the order of Ci→Ti→Di-Dn→K3→L→T0→ground. The conduction time of the second switch T0 is set to t on , and then the control unit controls the second switch T0 to be actively turned off, and the large current is transferred to the buffer branch (composed of diode Cs, capacitor Cs, and resistor Rs) and metal oxide surge arrester MOV to realize current absorption. The above process is repeated m times, that is, m continuous current pulses are realized (each cycle realizes the discharge of a certain capacitor and forms a continuous current pulse). The control timing diagram of the relays (K1-K3) and high-voltage IGBT switches (T0-Tn) in the capacitor discharging phase in time sequence is shown in Figure 4 .

[0085] The preset number m (1≤m≤n) of required continuous current pulses, the interval Δt, and the conduction time t on of T0 are programmably set by the control unit. Adjusting the interval Δt can adjust the frequency f of the current pulse:

[0086]

[0087] Adjusting the conduction time t on of T0 can adjust the width of the current pulse, which can be approximately considered to be equal to the conduction time t on of T0.

[0088] In the capacitor residual charge release phase, under the condition that the preset residual charge release time is met, the control unit controls the first relay and the third relay to be opened, and the second relay to be closed, thereby completing the release of the residual charge of the n capacitors.

[0089] Specifically, to ensure the safety of the experimenters and the stability of the system during continuous experiments, the residual charge of the capacitors C1-Cn needs to be released to ensure that the upper and lower plates of the capacitors are at zero potential. In the capacitor residual charge release phase, the control timing diagram of the relays K1-K3 and the high-voltage IGBT switches T0-Tn is as shown in Figure 5 d The capacitor residual charge release time T is generally 5-6 time constants.

[0090] As an optional implementation, the calculation formula of the preset residual charge release time is as follows:

[0091] T d = 5CR2.

[0092] Wherein, T d is the preset residual charge release time; and R2 is the resistance value of the second protective resistor.

[0093] When the control method for the continuous current pulse generation circuit for power device testing is used to control the continuous current pulse generation circuit for power device testing, in the capacitor charging phase, the voltage curve and the current curve of the capacitor are as shown in Figure 6 and Figure 7 . When the capacitor is charged, the voltage rises linearly, and after reaching the output voltage of the high-voltage DC power supply, the charging loop current decreases to zero, and the capacitor completes charging. In the capacitor timing discharge phase, the current diagram of the experimental sample of the power device is as shown in Figure 8 . The experimental sample is subjected to continuous current pulse stress.

[0094] The circuit and method of the application have the following advantages: flexible and adjustable pulse number: the user can set the required number of overcurrent pulses to meet the testing requirements of different numbers of continuous current pulses; high pulse amplitude consistency and high precision: by simultaneously charging the capacitors in parallel and controlling the capacitors to discharge independently in time, energy coupling between the capacitors is effectively avoided, and the consistency of the peak current of each pulse is good; adjustable current pulse time: by adjusting the control timing of the high-voltage IGBT switch T0, dynamic control of the pulse width edge is realized, which is suitable for device electrical characteristic modeling and thermal shock testing; adjustable pulse generation frequency: the control unit can realize accurate adjustment of the current pulse generation frequency by controlling the switching timing of the high-voltage IGBT switch. Therefore, the application is suitable for continuous current pulse testing of power devices in actual operating environment, and has important engineering application value for device research and development, selection and quality screening. ​

[0095] Any combination of the technical features in the above embodiments can be made. For the sake of brevity, the foregoing description has not described all possible combinations of the technical features in the above embodiments, however, it is understood that any combination of the technical features is within the scope of the present application as long as there is no contradiction.

[0096] The principles and implementation manners of the present application are described herein by using specific examples, and the above embodiments are only used to help understand the circuit, method and core idea of the present application; meanwhile, according to the idea of the present application, the specific implementation manners and application scopes will be changed by those skilled in the art. In conclusion, the content of the present application should not be understood as a limitation.

Claims

1. A continuous current pulse generating circuit for testing power devices, characterized in that, The continuous current pulse generating circuit for power device testing includes: a power supply, a control unit, a switching unit, an energy storage unit, an inductive load, and a current absorption unit. The switching unit includes: a first relay, a second relay, a third relay, n first switches, and 1 second switch; the energy storage unit includes: n capacitors; The i-th capacitor is connected in series with the i-th first switch to form the i-th series structure; n>1; 1≤i≤n; The first relay, the second relay, the third relay, each of the first switch and the second switch are respectively connected to the control unit; One end of the first relay is connected to the positive terminal of the power supply, and the other end of the first relay is connected to one end of each series structure, one end of the second relay, and one end of the third relay; the other end of the third relay is connected to one end of the inductive load, the other end of the inductive load is connected to one end of the power device and one end of the current absorption unit, and the other end of the power device is connected to one end of the second switch. The negative terminal of the power supply, the other end of each series structure, the other end of the second relay, the other end of the second switch, and the other end of the current absorption unit are all grounded; The control unit is used to control the on / off state of the first relay, the second relay, the third relay, and n first switches and second switches respectively, and to control each capacitor in different stages to provide continuous current pulses for the testing of power devices. The different stages include: capacitor charging stage, capacitor discharging stage according to time sequence, and capacitor residual charge release stage.

2. The continuous current pulse generating circuit for power device testing according to claim 1, characterized in that, The continuous current pulse generating circuit for power device testing further includes: a first protection resistor and a second protection resistor. One end of the first relay is connected to the positive terminal of the power supply through the first protective resistor; The other end of the second switch is grounded through the second protective resistor.

3. The continuous current pulse generating circuit for power device testing according to claim 1, characterized in that, The continuous current pulse generating circuit for power device testing further includes: an isolation unit; the isolation unit includes: n isolation diodes; One end of the j-th isolation diode is connected to one end of the j-th first switch, and the other end of the j-th isolation diode is connected to one end of the (j+1)-th first switch, where 1≤j≤n-1; One end of the nth isolation diode is connected to one end of the nth first switch, and the other end of the nth isolation diode is connected to one end of the second relay and one end of the third relay.

4. The continuous current pulse generating circuit for power device testing according to claim 1, characterized in that, The current absorption unit includes: a diode, a capacitor, a resistor, and a metal oxide surge arrester; One end of the diode is connected to the other end of the inductive load, one end of the power device, and one end of the metal oxide surge arrester, respectively; the other end of the diode is connected to one end of the capacitor and one end of the resistor, respectively. The other end of the capacitor, the other end of the resistor, and the other end of the metal oxide surge arrester are all grounded.

5. The continuous current pulse generating circuit for power device testing according to claim 1, characterized in that, The control unit is a computer or an embedded controller.

6. The continuous current pulse generating circuit for power device testing according to claim 1, characterized in that, The power source is a high-voltage DC power source.

7. The continuous current pulse generating circuit for power device testing according to claim 1, characterized in that, Both the first switch and the second switch are high-voltage IGBT switches.

8. A control method for a continuous current pulse generating circuit for power device testing, used to control the continuous current pulse generating circuit for power device testing as described in any one of claims 1-7, characterized in that, The control method for the continuous current pulse generation circuit used for power device testing includes: During the capacitor charging phase, the control unit controls the first relay to close, and the second and third relays to open. All n first and second switches remain in the off state. The power supply forms a charging path through the n first switches to charge the n capacitors in parallel. When the voltage of each capacitor reaches the voltage output by the power supply, the control unit controls the first relay to open, thus ending the capacitor charging phase. During the timed discharge phase of the capacitor, the control unit controls the first and second relays to open and the third relay to close. Based on the preset number of continuous current pulses required, the control unit controls a preset number of capacitors to discharge sequentially, starting from one first switch, at preset time intervals. The discharge process of the i-th capacitor includes: the control unit controls the i-th first switch to turn on, forming a current pulse path in the order of i-th capacitor → i-th first switch → third relay → inductive load → second switch → ground. After the preset on time of the second switch, the control unit controls the second switch to turn off actively, and the large current is transferred to the current absorption unit to achieve current absorption and complete the discharge of the i-th capacitor. During the residual charge release phase of the capacitors, under the condition of meeting the preset residual charge release time, the control unit controls the first and third relays to open and the second relay to close, thereby completing the release of residual charge from n capacitors.

9. The control method for the continuous current pulse generating circuit for power device testing according to claim 8, characterized in that, The formula for calculating the charging time during the capacitor charging phase is as follows: Among them, T C The charging time is the time during the capacitor charging phase; n is the number of capacitors; C is the capacitance of each capacitor; U0 is the output voltage of the power supply; and I is the output current of the power supply.

10. The control method for the continuous current pulse generating circuit for power device testing according to claim 9, characterized in that, The formula for calculating the preset residual charge release time is: T d =5CR2; Among them, T d R1 is the preset residual charge release time; R2 is the resistance value of the second protection resistor.

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