Protection device and protection system

Abstract

The present application provides a protection device and a protection system, relating to the field of power electronics technology. The protection device includes: a digital control unit and a processing unit. Among them, the digital control unit can generate a reference signal based on a pre-configured protection threshold and output the reference signal to the processing unit. The processing unit generates a turn-on / off signal according to the reference signal and the sampled current signal in the double-pulse test system, and sends the turn-on / off signal to the control end of the protection switch device to control the turn-on and turn-off of the protection switch device. Therefore, based on the configurable protection threshold and the sampled current signal in the double-pulse test system, the present solution generates a turn-on / off signal that can control the protection switch device to perform turn-on and turn-off actions, realizing the rapid cut-off of the protection switch device, and thus can avoid damage to the device under test in the double-pulse test system during testing; at the same time, in order to meet different test requirements, the protection threshold in the protection device can be flexibly adjusted, improving the applicability of the protection device.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and more particularly, to a protection device and a protection system. Background Art

[0002] Generally, a large number of operating conditions tests need to be carried out on power devices applied to electric vehicles to determine the safe operating range of the power devices. For example, a double-pulse test scheme is adopted to test the performance of the power devices.

[0003] In the related art, to avoid damage to the power device under test during the test (for example, short-circuit failure), usually, a tester with rich test experience monitors the real-time test data, such as monitoring the waveform data of an oscilloscope, and relies on experience to judge whether the monitored data may cause the power device under test to exceed the safe operating range under the current test conditions and even the next test conditions.

[0004] However, the test method relying on manual monitoring severely restricts the possibility of carrying out a large number of operating conditions tests on the power device under test, resulting in insufficient testing of all operating conditions of the power device under test. Summary of the Invention

[0005] The purpose of this application is to provide a protection device and a protection system for the deficiencies in the above-mentioned existing technologies, so as to solve the technical problems existing in the existing technologies.

[0006] To achieve the above purpose, the technical solutions adopted in the embodiments of this application are as follows:

[0007] In a first aspect, an embodiment of this application provides a protection device, and the device includes: a digital control unit and a processing unit;

[0008] The input end of the digital control unit is used to receive protection thresholds, and the protection thresholds include: a current protection threshold and a time protection threshold;

[0009] The output end of the digital control unit is connected to the input end of the processing unit, and the output end of the processing unit is connected to the control end of a protection switch device;

[0010] The digital control unit is used to generate a reference signal for the protection switch device according to the protection thresholds, and input the reference signal into the processing unit. The reference signal includes: a time threshold signal and a reference current signal, and the time threshold signal is used to represent the time protection threshold;

[0011] The processing unit is configured to obtain a sampled current signal in the dual-pulse test system, generate an on / off signal of the protection switch device according to the sampled current signal and the reference signal, and send the on / off signal to the protection switch device to control the on / off of the protection switch device.

[0012] Optionally, the processing unit includes: a filtering unit and a comparison unit;

[0013] A first input end of the filtering unit is connected to a first output end of the digital control unit, and a second input end of the filtering unit is configured to access the sampled current signal in the dual-pulse test system collected by a current sensor;

[0014] An output end of the filtering unit is connected to an inverting input end of the comparison unit;

[0015] A non-inverting input end of the comparison unit is connected to a second output end of the digital control unit;

[0016] An output end of the comparison unit is connected to a control end of the protection switch device;

[0017] The filtering unit is configured to generate a filtered current signal according to the sampled current signal and the time threshold signal, and output the filtered current signal to the inverting input end of the comparison unit;

[0018] The comparison unit is configured to generate a driving voltage signal according to the filtered current signal and the reference current signal, so as to generate the on / off signal through the driving voltage signal.

[0019] Optionally, the processing unit further includes: a voltage adjustment unit; the reference signal further includes a reference voltage signal;

[0020] A first input end of the voltage adjustment unit is connected to a third output end of the digital control unit, a second input end of the voltage adjustment unit is connected to an output end of the comparison unit, and an output end of the voltage adjustment unit is connected to a control end of the protection switch device;

[0021] The comparison unit is further configured to output the driving voltage signal to the voltage adjustment unit;

[0022] The voltage adjustment unit is configured to generate the on / off signal according to the driving voltage signal and the reference voltage signal, and send the on / off signal to the control end of the protection switch device.

[0023] Optionally, the voltage adjustment unit includes: a first voltage adjustment subunit and a second voltage adjustment subunit;

[0024] The first input terminal of the first voltage adjustment subunit is connected to the third output terminal of the digital control unit, the second input terminal of the first voltage adjustment subunit is connected to the output terminal of the comparison unit, and the output terminal of the first voltage adjustment subunit is connected to the control terminal of the protection switch device;

[0025] The first input terminal of the second voltage adjustment subunit is connected to the third output terminal of the digital control unit, the second input terminal of the second voltage adjustment subunit is connected to the output terminal of the comparison unit, and the output terminal of the second voltage adjustment subunit is connected to the control terminal of the protection switch device.

[0026] Optionally, the first voltage adjustment subunit includes: a first voltage adjustment module, a first capacitor, and a first triode;

[0027] The input terminal of the first voltage adjustment module is connected to the third output terminal of the digital control unit, and the output terminal of the first voltage adjustment module is respectively connected to one end of the first capacitor and the first end of the first triode;

[0028] The other end of the first capacitor is connected to the ground terminal;

[0029] The second end of the first triode is connected to the output terminal of the comparison unit, and the third end of the first triode is connected to the control terminal of the protection switch device.

[0030] Optionally, the second voltage adjustment subunit includes: a second voltage adjustment module, a second capacitor, and a second triode;

[0031] The input terminal of the second voltage adjustment module is connected to the third output terminal of the digital control unit, and the output terminal of the second voltage adjustment module is respectively connected to one end of the second capacitor and the first end of the second triode;

[0032] The other end of the second capacitor is connected to the ground terminal;

[0033] The second end of the second triode is connected to the output terminal of the comparison unit, and the third end of the second triode is connected to the control terminal of the protection switch device.

[0034] Optionally, the filtering unit includes: a first switch, a first resistor, a second switch, a second resistor, a third switch, a third resistor, a third capacitor, and an amplifier;

[0035] One end of the first switch is connected to one end of the first resistor;

[0036] One end of the second switch is connected to one end of the second resistor;

[0037] One end of the third switch is connected to one end of the third resistor;

[0038] The other end of the first switch, the other end of the second switch and the other end of the third switch are all connected to the first output end of the digital control unit and the output end of the current sensor arranged in the dual-pulse system;

[0039] The other end of the first resistor, the other end of the second resistor and the other end of the third resistor are all connected to one end of the third capacitor, the inverting input end of the amplifier and the output end of the amplifier;

[0040] The other end of the third capacitor and the non-inverting input end of the amplifier are both connected to the ground terminal;

[0041] The output end of the amplifier is connected to the inverting input end of the comparison unit.

[0042] Optionally, the digital control unit is specifically configured to:

[0043] Determine the time threshold signal, the reference current signal and the reference voltage signal according to the current protection threshold, the time protection threshold and a preset mapping table, where the mapping table records the corresponding relationships between multiple protection thresholds and the reference signals corresponding to each protection threshold.

[0044] Optionally, the reference voltage signal includes: a first reference voltage signal and a second reference voltage signal;

[0045] The voltage adjustment unit is specifically configured to:

[0046] If the drive voltage signal is 1, the generated on-off signal is the first reference voltage signal;

[0047] If the drive voltage signal is 0, the generated on-off signal is the second reference voltage signal.

[0048] In a second aspect, an embodiment of the present application further provides a protection system, and the protection system includes: the protection device, the protection switch device and the dual-pulse test system provided in the first aspect above;

[0049] The protection switch device includes: a voltage-controlled device;

[0050] The gate of the voltage-controlled device is connected to the output end of the processing unit in the protection device;

[0051] The source of the voltage-controlled device is connected to one end of the negative pole of the DC bus in the dual-pulse test system; the drain of the voltage-controlled device is connected to the other end of the negative pole of the DC bus.

[0052] The beneficial effects of the present application are as follows:

[0053] The present application provides a protection device and a protection system. The protection device includes a digital control unit and a processing unit. Among them, the digital control unit can generate a reference signal based on a pre-configured protection threshold and output the reference signal to the processing unit. The processing unit generates a turn-on / off signal according to the reference signal and the sampled current signal in the double-pulse test system, and sends the turn-on / off signal to the control end of the protection switch device to control the turn-on and turn-off of the protection switch device. Therefore, based on the configurable protection threshold and the sampled current signal in the double-pulse test system, this solution generates a turn-on / off signal that can control the protection switch device to perform turn-on and turn-off actions, realizing the rapid cut-off of the protection switch device, and thus can avoid damage to the device under test in the double-pulse test system during testing. At the same time, in order to meet different test requirements, the protection threshold in the protection device can be flexibly adjusted, improving the applicability of the protection device. Description of the Drawings

[0054] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0055] Figure 1 Structural schematic of the protection device provided in the embodiment of the present application Figure 1 ;

[0056] Figure 2 Schematic diagram of an example where the protection switch device provided in the embodiment of the present application is an IGBT device;

[0057] Figure 3 Schematic diagram of an example where the protection switch device provided in the embodiment of the present application is a MOSFET device;

[0058] Figure 4 Structural schematic of the protection device provided in the embodiment of the present application Figure 2 ;

[0059] Figure 5 Structural schematic of the protection device provided in the embodiment of the present application Figure 3 ;

[0060] Figure 6 Structural schematic diagram of the voltage adjustment unit in the protection device provided in the embodiment of the present application;

[0061] Figure 7 Structural schematic diagram of each voltage adjustment subunit in the voltage adjustment unit of the protection device provided in the embodiment of the present application;

[0062] Figure 8 It is a schematic structural diagram of the filtering unit in the protection device provided by the embodiment of the present application;

[0063] Figure 9 It is a schematic structural diagram of the protection system provided by the embodiment of the present application.

[0064] Icons: 100 - protection device; 101 - power device under test; 102 - double pulse test system; 103 - double pulse test loop; 104 - support capacitor; 1 - digital control unit; 2 - processing unit; 21 - filtering unit; 22 - comparison unit; 23 - voltage adjustment unit; 231 - first voltage adjustment subunit; 232 - second voltage adjustment subunit; 2311 - first voltage adjustment module; 2321 - second voltage adjustment module; 200 - protection system. Specific embodiments

[0065] The technical solutions of the specific embodiments will be described below with reference to the accompanying drawings.

[0066] It should be noted that: Although this specification has described the present invention in detail with reference to the above embodiments, those of ordinary skill in the art should understand that those skilled in the art can still modify, combine, or equivalently replace the present invention. All technical solutions and their improvements that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

[0067] First, the prior art related to the present application will be introduced.

[0068] Compared with Si IGBT devices, SiC MOSFETs have the advantages of higher switching speed, lower switching losses, and better high-temperature resistance. Therefore, the application of SiC MOSFET devices can significantly improve the power density and efficiency of the system and reduce the system volume. Currently, SiC MOSFETs have been increasingly widely used in fields such as electric vehicles. However, the short-circuit withstand time of SiC MOSFETs (2 - 3 μs) is much shorter than that of Si IGBT devices (10 - 12 μs). Therefore, higher requirements and challenges are put forward for the short-circuit test method of SiC MOSFETs.

[0069] Generally, during the performance test of SiC MOSFET devices using a double-pulse test scheme, after the power device under test is damaged (for example, short-circuit failure), it will cause the large-capacity bus capacitor in the test system to continuously supply energy to the power device under test and the loop, resulting in a continuous increase in the current in the system, which may cause secondary damage to the system.

[0070] In the prior art, in a test system, to avoid damage to the power device under test during testing (e.g., short - circuit failure), usually, testers with rich testing experience monitor the real - time test data, such as monitoring the waveform data of an oscilloscope, and rely on experience to judge whether the monitored data may cause the power device under test to exceed the safe operating range under the current test conditions and even the next test conditions. Thus, in the case of abnormal system current, the path between the energy - storage capacitor and the faulty system can be quickly cut off within a short time (e.g., 2 μs) to avoid the out - of - control of the fault current / energy and damage to other components of the test system.

[0071] However, the test method of manual monitoring severely restricts the possibility of conducting a large number of working - condition tests on the power device under test, resulting in insufficient testing of all working conditions of the power device under test.

[0072] To address the above problems, the present application proposes a protection device. The protection device includes: a digital control unit and a processing unit. Among them, the digital control unit can generate a reference signal based on a pre - configured protection threshold and output the reference signal to the processing unit. The processing unit generates a turn - on / off signal according to the reference signal and the sampled current signal in the double - pulse test system, and sends the turn - on / off signal to the control end of the protection switch device to control the turn - on and off of the protection switch device. Therefore, based on the configurable protection threshold and the sampled current signal in the double - pulse test system, this solution generates a turn - on / off signal that can control the protection switch device to perform turn - on and off actions, realizing the quick cut - off of the protection switch device. Furthermore, it can avoid damage to the power device under test in the double - pulse test system. For example, when the sampled current signal in the double - pulse test system exceeds the set protection threshold, the turn - off signal can be generated to control the turn - off of the protection switch device, achieving the quick cut - off of the fault current. At the same time, to meet the test requirements of power devices with different current levels, the protection threshold in this protection device can be flexibly adjusted, improving the applicability of the protection device.

[0073] The structure of the protection device provided by the present application will be introduced in detail through the following embodiments.

[0074] Optionally, as shown in Figure 1 the protection device 100 includes: a digital control unit 1 and a processing unit 2. Exemplarily, for example, the digital control unit 1 can be a digital controller, and the processing unit 2 can be a chip with data - processing functions.

[0075] The input terminal of the digital control unit 1 is used to receive protection thresholds, which include: the current protection threshold Ip and the time protection threshold Tp. Among them, in order to meet different test requirements, the protection thresholds input to the digital control unit 1 can be flexibly adjusted. For example, under high protection thresholds and small protection time requirements, a small time protection threshold Tp is configured to improve the detection speed of the system and the protection rate; under low protection threshold conditions, a long time protection threshold Tp can be configured to reduce the misoperation of the system and enhance the anti-interference characteristics.

[0076] The output terminal of the digital control unit 1 is connected to the input terminal of the processing unit 2, and the output terminal of the processing unit 2 is connected to the control terminal of the protection switch device. Continuing to refer to Figure 1 As shown, the protection switch device is connected in series between the support capacitor 104 and the double-pulse loop in the double-pulse test system 102, and the power device 101 under test in the double-pulse loop can be protected through the protection switch device. For example, the protection switch device can be: a voltage-controlled device, as shown in Figures 2 - 3 As shown, the voltage-controlled devices include but are not limited to silicon-based MOSFET devices, IGBT devices, SiC MOSFET devices, GaN power voltage-controlled devices, etc.

[0077] Continuing to refer to Figure 1 As shown, the digital control unit 1 is used to generate a reference signal for the protection switch device according to the protection threshold and input the reference signal to the processing unit 2, where the reference signal includes: the time threshold signal Tf and the reference current signal Iref, and the time threshold signal is used to represent the time protection threshold; for example, the time threshold signal can be the digital signal obtained after binary conversion of the time protection threshold. For example, if the user inputs a time protection threshold of 2 μs, after binary conversion of 2 μs, the obtained digital signal is 11, that is, the time threshold signal is 11.

[0078] The processing unit 2 is used to obtain the sampled current signal Id in the double-pulse test system 102, and generate a turn-on / off signal Vg for the protection switch device according to the sampled current signal Id and the reference signal, and send the turn-on / off signal Vg to the protection switch device to control the turn-on and turn-off of the protection switch device.

[0079] In this embodiment, during the double-pulse test of the object under test, the processing unit 2 generates an on-off signal for the protection switch device according to the sampled current signal in the double-pulse test system 102 and the reference signal generated by the digital control unit 1, and sends the on-off signal to the protection switch device to control the on-off of the protection switch device, so as to quickly cut off the fault current in the double-pulse test system 102, achieving the purpose of quickly protecting the power device 101 under test and avoiding damage to the power device 101 under test in the double-pulse test system 102 during the test. At the same time, based on the flexibly configurable protection threshold, a large number of working conditions of the power device 101 under test can be tested, meeting the requirement of fully testing various working conditions of the power device 101 under test and ensuring the accuracy of the test results.

[0080] In summary, the embodiment of the present application provides a protection device, which includes a digital control unit and a processing unit. Among them, the digital control unit can generate a reference signal based on a pre-configured protection threshold and output the reference signal to the processing unit. The processing unit generates an on-off signal according to the reference signal and the sampled current signal in the double-pulse test system, and sends the on-off signal to the control end of the protection switch device to control the on-off of the protection switch device. Therefore, based on the configurable protection threshold and the sampled current signal in the double-pulse test system, this solution generates an on-off signal that can control the protection switch device to perform on-off actions, realizing the quick cut-off of the protection switch device, and further avoiding damage to the power device under test in the double-pulse test system during the test. At the same time, in order to meet different test requirements, the protection threshold in the protection device can be flexibly adjusted, improving the applicability of the protection device.

[0081] The structure of the processing unit 2 provided by the present application will be specifically introduced through the following embodiments.

[0082] Optionally, as shown in Figure 4 Figure, the processing unit 2 includes a filtering unit 21 and a comparison unit 22.

[0083] Exemplarily, the filtering unit 21 can be a digital filtering unit 21 or an analog filtering unit 21, and is used to filter the sampled current signal in the double-pulse test system 102 to filter out the interference signal in the sampled current signal.

[0084] The first input end of the filtering unit 21 is connected to the first output end of the digital control unit 1, and the second input end of the filtering unit 21 is used to access the sampled current signal Id in the double-pulse test system 102 collected by the current sensor.

[0085] The output end of the filtering unit 21 is connected to the inverting input end of the comparison unit 22.

[0086] The non-inverting input terminal of the comparison unit 22 is connected to the second output terminal of the digital control unit 1.

[0087] The output terminal of the comparison unit 22 is connected to the control terminal of the protection switch device.

[0088] The filtering unit 21 is configured to generate a filtered current signal If according to the sampled current signal Id and the time threshold signal Tf, and output the filtered current signal If to the inverting input terminal of the comparison unit 22. Therefore, in this embodiment, the filtering unit 21 uses the time threshold signal Tf as its own filtering constant, and based on the time threshold signal, filters the sampled current signal Id to obtain the filtered current signal If, so as to ensure the sampling speed of the current signal in the double-pulse test system 102 and improve the protection rate.

[0089] The comparison unit 22 is configured to generate a drive voltage signal Vdrive according to the filtered current signal If and the reference current signal Iref, so as to generate a turn-on / off signal Vg through the drive voltage signal Vdrive.

[0090] In this embodiment, the comparison unit 22 can compare the filtered current signal If with the reference current signal Iref. If the filtered current signal If is greater than the reference current signal Iref, the drive voltage signal Vdrive output by the comparison unit 22 is 0, and the drive voltage signal Vdrive is used as the turn-on / off signal Vg, so as to send the turn-on / off signal Vg to the protection switch device to control the rapid turn-off of the protection switch device and achieve the rapid protection function. For another example, if the filtered current signal If is less than or greater than the reference current signal Iref, the drive voltage signal Vdrive output by the comparison unit 22 is 1, and the drive voltage signal Vdrive is used as the turn-on / off signal Vg, so as to send the turn-on / off signal Vg to the protection switch device to control the rapid conduction of the protection switch device and achieve the rapid protection function.

[0091] Optionally, referring to Figure 5 as shown, the processing unit 2 further includes: a voltage adjustment unit 23; and the reference signal further includes a reference voltage signal.

[0092] Continuing to refer to Figure 5 as shown, the first input terminal of the voltage adjustment unit 23 is connected to the third output terminal of the digital control unit 1, the second input terminal of the voltage adjustment unit 23 is connected to the output terminal of the comparison unit 22, and the output terminal of the voltage adjustment unit 23 is connected to the control terminal of the protection switch device;

[0093] The comparison unit 22 is further configured to output the drive voltage signal to the voltage adjustment unit 23;

[0094] A voltage adjustment unit 23, configured to generate a turn-on / off signal according to a drive voltage signal and a reference voltage signal, and send the turn-on / off signal to the control terminal of the protection switch device.

[0095] In another implementable manner, in order to avoid the problem of a long turn-off time when the protection switch device starts to execute the turn-off instruction from the deep saturation conduction state after receiving the turn-off signal sent by the comparison unit 22, it is proposed that the processing unit 2 provided in this application further includes: a voltage adjustment unit 23, that is, the voltage adjustment unit 23 generates a turn-on / off signal Vg based on the voltage drive signal Vdrive and the reference voltage signal Vref output by the comparison unit 22, and sends the turn-on / off signal Vg to the control terminal of the protection switch device to control the turn-on and turn-off of the protection switch device. In this way, when the protection switch device is in the deep saturation conduction state, it can quickly complete the state transition based on the received turn-on / off signal Vg, improving the turn-off speed of the protection switch device, reducing the turn-off delay, and realizing the fast protection of the power device under test 101.

[0096] In summary, in this embodiment, considering that in some current solutions for protecting the power device under test 101 in the double-pulse test system 102, the adopted protection solution is: using sensors such as Pearson and Rogowski coils to detect the system current, and the detected signal is sent to the comparison unit 22 through the sensor. That is, when the detected current exceeds the threshold, the turn-off instruction of the solid-state switch is executed. There are the following two problems with this solution:

[0097] (1) The current sensor and related signal conditioning and comparison links cannot be adaptively adjusted, affecting the protection speed; to address this problem, the filtering unit 21 provided in this application filters the sampled current signal Id based on the time threshold signal to obtain the filtered current signal If, ensuring the sampling speed of the current signal in the double-pulse test system 102 and improving the protection rate.

[0098] (2) After the protection switch device receives the turn-off signal sent by the comparison unit 22, it starts to execute the turn-off instruction from the deep saturation conduction state, and the turn-off time is long, affecting the protection speed. To address this problem, the processing unit 2 provided in this application further includes: a voltage adjustment unit 23, that is, the voltage adjustment unit 23 generates a turn-on / off signal based on the voltage drive signal and the reference voltage signal output by the comparison unit 22, and sends the turn-on / off signal to the protection switch device to control the turn-on and turn-off of the protection switch device, avoiding the protection switch device directly switching from the deep saturation conduction state to the turn-off state, reducing the turn-off delay of the protection switch device, increasing the turn-off speed of the protection switch device, and realizing the fast protection of the power device under test 101.

[0099] The following embodiments will specifically describe the above Figure 5The structure of the voltage adjustment unit 23 in it will be introduced in detail.

[0100] Optionally, referring to Figure 6 As shown, the voltage adjustment unit 23 includes: a first voltage adjustment subunit 231 and a second voltage adjustment subunit 232;

[0101] The first input end of the first voltage adjustment subunit 231 is connected to the third output end of the digital control unit 1, the second input end of the first voltage adjustment subunit 231 is connected to the output end of the comparison unit 22, and the output end of the first voltage adjustment subunit 231 is connected to the control end of the protection switch device;

[0102] The first input end of the second voltage adjustment subunit 232 is connected to the third output end of the digital control unit 1, the second input end of the second voltage adjustment subunit 232 is connected to the output end of the comparison unit 22, and the output end of the second voltage adjustment subunit 232 is connected to the control end of the protection switch device.

[0103] In this embodiment, considering that there are two cases for the driving voltage signal output by the comparison unit 22, therefore, the driving voltage signal can be adjusted by the first voltage adjustment subunit 231 and the second voltage adjustment subunit 232 in the voltage adjustment unit 23, and an on-off signal is generated. For example, when the driving voltage signal is the first driving voltage signal Vdrive1, the first voltage adjustment subunit 231 can adjust the first driving voltage signal Vdrive1 and the reference voltage signal Vref to generate a first on-off signal Vg1; and when the driving voltage signal is the second driving voltage signal Vdrive0, the first voltage adjustment subunit 231 can adjust the first driving voltage signal Vdrive0 and the reference voltage signal Vref to generate a second on-off signal Vg2. In this way, the protection switch device can directly switch from the deep saturation off state to the on state based on the first on-off signal Vg1, or directly switch from the deep saturation on state to the off state based on the second on-off signal Vg2, reducing the switching delay of the protection switch device and improving the switching speed of the protection switch device, realizing the rapid protection of the power device under test 101. Therefore, the on-off signal generated by the voltage adjustment unit 23 can be used to improve the action time of the protection switch device.

[0104] Optionally, referring to Figure 7 As shown, the first voltage adjustment subunit 231 includes: a first voltage adjustment module 2311, a first capacitor C1, and a first triode Q1;

[0105] The input end of the first voltage adjustment module 2311 is connected to the third output end of the digital control unit 1, and the output end of the first voltage adjustment module 2311 is respectively connected to one end of the first capacitor and the first end of the first triode;

[0106] The other end of the first capacitor is connected to the ground terminal;

[0107] The second end of the first triode is connected to the output end of the comparison unit 22, and the third end of the first triode is connected to the control end of the protection switch device.

[0108] Among them, the first voltage adjustment module 2311 is used to adjust and process the reference voltage signal Vref to generate the first gate voltage of the protection switch device. For example, the first voltage adjustment module 2311 can generate the first gate voltage Vcc of the protection switch device according to the reference voltage signal Vref; when the driving voltage signal received by the first triode is Vdrive1, the first gate voltage Vcc can be used as the first on-off signal Vg1, that is, Vcc = Vg1. In this way, the protection switch device can directly switch from the deep saturation off state to the on state based on the first on-off signal Vg1, realizing the fast conduction of the protection switch device.

[0109] Optionally, continue to refer to Figure 7 As shown, the second voltage adjustment sub-unit includes: a second voltage adjustment module 2321, a second capacitor, and a second triode;

[0110] The input end of the second voltage adjustment module 2321 is connected to the third output end of the digital control unit 1, and the output end of the second voltage adjustment module 2321 is respectively connected to one end of the second capacitor and the first end of the second triode;

[0111] The other end of the second capacitor is connected to the ground terminal;

[0112] The second end of the second triode is connected to the output end of the comparison unit 22, and the third end of the second triode is connected to the control end of the protection switch device.

[0113] Among them, the second voltage adjustment module 2321 is used to adjust and process the reference voltage signal Vref to generate the second gate voltage Vee of the protection switch device. When the driving voltage signal received by the second triode is Vdrive0, the second gate voltage Vee can be used as the second on-off signal Vg1, that is, Vee = Vg2. In this way, the protection switch device can directly switch from the deep saturation on state to the off state based on the second on-off signal Vg2, realizing the fast turn-off of the protection switch device to protect the measured power device 101 from being damaged.

[0114] The following embodiments will specifically describe the above Figure 4The structure of the filtering unit 21 in it will be introduced in detail.

[0115] Optionally, refer to Figure 8 As shown, the filtering unit 21 includes: a first switch S1, a first resistor R1, a second switch S2, a second resistor R2, a third switch S3, a third resistor R3, a third capacitor C3 and an amplifier A; in this example, the filtering unit 21 is an RC filter.

[0116] One end of the first switch S1 is connected to one end of the first resistor R1;

[0117] One end of the second switch S2 is connected to one end of the second resistor R2;

[0118] One end of the third switch S3 is connected to one end of the third resistor R3;

[0119] The other ends of the first switch S1, the second switch S2 and the third switch S3 are all connected to the first output end of the digital control unit 1 and the output end of the current sensor arranged in the double-pulse system;

[0120] The other ends of the first resistor R1, the second resistor R2 and the third resistor R3 are all connected to one end of the third capacitor C3, the inverting input end of the amplifier A and the output end of the amplifier A;

[0121] The other end of the third capacitor C3 and the non-inverting input end of the amplifier A are both connected to the ground terminal;

[0122] The output end of the amplifier A is connected to the inverting input end of the comparison unit 22.

[0123] In this embodiment, for example, when the time threshold signal received by the filtering unit 21 is Tf1, the first switch S1 is controlled to close, that is, the sampling current signal Id is filtered by the first resistor R1, the third capacitor C3 and the amplifier A to generate a first filtered current signal If1; for another example, when the time threshold signal received by the filtering unit 21 is Tf2, the second switch S2 is controlled to close, that is, the sampling current signal Id is filtered by the second resistor R2, the third capacitor C3 and the amplifier A to generate a second filtered current signal If2. That is, by adjusting the time threshold signal Tf, the delay of the sampling system can be reduced and the dynamic performance of the protection system 200 can be improved.

[0124] Optionally, the digital control unit 1 is specifically configured to:

[0125] According to the current protection threshold, the time protection threshold and a preset mapping table, determine the time threshold signal, the reference current signal and the reference voltage signal. The mapping table records the corresponding relationships between multiple protection thresholds and the reference signals corresponding to each protection threshold.

[0126] In this embodiment, the digital control unit 1, after receiving the current protection threshold and the time protection threshold, uses the current protection threshold and the time protection threshold as query conditions to query the reference signals corresponding to the current protection threshold and the time protection threshold in the mapping table, that is, the time threshold signal, the reference current signal, and the reference voltage signal, to complete the configuration of the reference signals.

[0127] Optionally, the reference voltage signal includes: a first reference voltage signal Vcc and a second reference voltage signal Vee;

[0128] The voltage adjustment unit 23 is specifically configured to:

[0129] If the drive voltage signal is 1, the on-off signal generated according to the reference voltage signal is the first reference voltage signal Vcc;

[0130] If the drive voltage signal is 0, the generated on-off signal is the second reference voltage signal Vee.

[0131] In this example, for instance, when the drive voltage signal is the first drive voltage signal Vdrive1, the voltage adjustment unit 23 adjusts the reference voltage signal Vref according to the first drive voltage signal Vdrive1 to generate the first on-off signal Vg1 as Vcc; when the drive voltage signal is the second drive voltage signal Vdrive0, the voltage adjustment unit 23 adjusts the reference voltage signal Vref according to the second drive voltage signal Vdrive0 to generate the second on-off signal Vg2 as Vee. In this way, the protection switch device can directly switch from the deep saturation off state to the on state based on the first on-off signal Vg1, or directly switch from the deep saturation on state to the off state based on the second on-off signal Vg2, reducing the switching delay of the protection switch device and improving the switching speed of the protection switch device, achieving fast protection for the power device under test 101. Therefore, the on-off signal generated by the voltage adjustment unit 23 can be used to improve the action time of the protection switch device.

[0132] In summary, the digital control unit using the protection device provided in this application can flexibly configure the operating voltage of the protection switch device according to the current protection threshold and the time protection threshold. For example, under high protection threshold conditions, a high operating voltage Vcc (for example, the IGBT gate voltage is 18V) is configured to improve the current-carrying capacity of the system; under low protection threshold conditions, a low operating voltage Vcc (for example, the IGBT gate voltage is configured to 12V) is configured to reduce the turn-off delay of the power device and improve the turn-off speed of the protection switch device. And it is implemented based on the digital control unit, with strong anti-interference characteristics.

[0133] Optionally, reference Figure 9, as shown, the present application also provides a double-pulse test system 102, which includes: the protection device 100 provided in the above embodiment, a protection switch device, and the double-pulse test system 102.

[0134] Among them, the double-pulse test system 102 is mainly used for dynamic testing of power devices such as IGBTs. Through double-pulse testing, the performance of power devices can be conveniently evaluated, the main parameters in the steady-state and dynamic processes can be obtained, the device performance can be better evaluated, the drive design can be optimized, and so on.

[0135] The protection switch device includes: voltage-controlled devices, such as silicon-based MOSFET devices, IGBT devices, SiC MOSFET devices, and GaN power voltage-controlled devices, etc. And the protection switch device can be a single device or multiple devices connected in series / parallel.

[0136] Among them, the gate of the voltage-controlled device is connected to the output terminal of the processing unit 2 in the protection device 100.

[0137] The source of the voltage-controlled device is connected to one end of the negative pole DC- of the DC bus in the double-pulse test system 102; the drain of the voltage-controlled device is connected to the other end of the negative pole DC- of the DC bus.

[0138] Continue to refer to Figure 9 As shown, the double-pulse test system 102 includes: a DC power supply, a support capacitor 104, a protection switch device, and a double-pulse test circuit 103. Among them, the double-pulse test circuit 103 includes: a power device under test 101. When a fault current appears in the double-pulse test system 102, by controlling the on / off of the protection switch device, the rapid cut-off of the fault current can be achieved to prevent the support capacitor 104 from supplying energy to the power device under test 101 and the circuit, resulting in a continuous increase in the current in the system and causing damage to the power device under test 101.

[0139] In several embodiments provided by the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point, the displayed or discussed coupling or direct coupling or communication connection between each other can be through some interfaces. The indirect coupling or communication connection of the device or unit can be in an electrical, mechanical or other form.

[0140] The unit described as a separation component may or may not be physically separated. The component displayed as a unit may or may not be a physical unit, that is, it may be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0141] In addition, each functional unit in various embodiments of the present application may be integrated in a processing unit, may exist separately as individual physical units, or two or more units may be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of a combination of hardware and software functional units.

[0142] The above-mentioned integrated unit implemented in the form of a software functional unit can be stored in a computer-readable storage medium. The above-mentioned software functional unit stored in a storage medium includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor (English: processor) to execute some steps of the methods described in various embodiments of the present application. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (English: Read-Only Memory, abbreviated as: ROM), random access memories (English: Random Access Memory, abbreviated as: RAM), magnetic disks, or optical discs that can store program codes.

Claims

1. A protection device, characterized in that: The device comprises: a digital control unit and a processing unit; The input end of the digital control unit is used to receive a protection threshold, wherein the protection threshold includes: a current protection threshold and a time protection threshold; The output end of the digital control unit is connected to the input end of the processing unit, and the output end of the processing unit is connected to the control end of the protection switch device; The digital control unit is used to generate a reference signal for protecting the switch device according to the protection threshold, and input the reference signal to the processing unit, wherein the reference signal includes: a time threshold signal and a reference current signal, and the time threshold signal is used to characterize the time protection threshold; The processing unit is used to obtain a sampling current signal in the double pulse test system, and generate an on-off signal of the protection switch device according to the sampling current signal and the reference signal, and send the on-off signal to the protection switch device to control the on-off of the protection switch device; Wherein, the processing unit includes: a filtering unit and a comparing unit; The first input end of the filter unit is connected to the first output end of the digital control unit, and the second input end of the filter unit is used to access the sampled current signal in the double pulse test system collected by the current sensor; The output end of the filtering unit is connected to the inverting input end of the comparing unit; The non-inverting input terminal of the comparison unit is connected to the second output terminal of the digital control unit; The output terminal of the comparison unit is connected to the control terminal of the protection switch device; The filtering unit is used to generate a filtered current signal according to the sampled current signal and the time threshold signal, and output the filtered current signal to the inverting input terminal of the comparison unit, the time threshold signal is used to dynamically adjust the filtered current signal, the filtering unit comprises: a plurality of switchable resistance branches, the time threshold signal is used to select the resistance branch to adjust the filtering parameters of the filtering unit; The comparison unit is used to generate a driving voltage signal according to the filtered current signal and the reference current signal, so as to generate the on-off signal through the driving voltage signal; Wherein, the processing unit further includes: a voltage adjustment unit; the reference signal further includes a reference voltage signal; The first input terminal of the voltage adjustment unit is connected to the third output terminal of the digital control unit, the second input terminal of the voltage adjustment unit is connected to the output terminal of the comparison unit, and the output terminal of the voltage adjustment unit is connected to the control terminal of the protection switch device; The comparison unit is further used to output the driving voltage signal to the voltage adjustment unit; The voltage adjustment unit is used to generate the on-off signal according to the driving voltage signal and the reference voltage signal, and send the on-off signal to the control terminal of the protection switch device; Wherein, the voltage adjustment unit includes: a first voltage adjustment subunit and a second voltage adjustment subunit; The first input terminal of the first voltage adjustment subunit is connected to the third output terminal of the digital control unit, the second input terminal of the first voltage adjustment subunit is connected to the output terminal of the comparison unit, and the output terminal of the first voltage adjustment subunit is connected to the control terminal of the protection switch device; The first input terminal of the second voltage adjustment subunit is connected to the third output terminal of the digital control unit, the second input terminal of the second voltage adjustment subunit is connected to the output terminal of the comparison unit, and the output terminal of the second voltage adjustment subunit is connected to the control terminal of the protection switch device; The first voltage adjustment subunit includes: a first voltage adjustment module, a first capacitor and a first triode; The input end of the first voltage adjustment module is connected to the third output end of the digital control unit, and the output end of the first voltage adjustment module is respectively connected to one end of the first capacitor and the first end of the first triode; The other end of the first capacitor is connected to the ground end; The second end of the first triode is connected to the output end of the comparison unit, and the third end of the first triode is connected to the control end of the protection switch device; The first voltage adjustment module is used to adjust the reference voltage signal to generate a first gate voltage of the protection switch device; The second voltage adjustment subunit includes: a second voltage adjustment module, a second capacitor and a second triode; The input end of the second voltage adjustment module is connected to the third output end of the digital control unit, and the output end of the second voltage adjustment module is respectively connected to one end of the second capacitor and the first end of the second transistor; The other end of the second capacitor is connected to the ground end; The second end of the second triode is connected to the output end of the comparison unit, and the third end of the second triode is connected to the control end of the protection switch device; The second voltage adjustment module is used to adjust the reference voltage signal to generate a second gate voltage for protecting the switch device.

2. The device according to claim 1, characterized in that The filtering unit includes: a first switch, a first resistor, a second switch, a second resistor, a third switch, a third resistor, a third capacitor and an amplifier; One end of the first switch is connected to one end of the first resistor; One end of the second switch is connected to one end of the second resistor; One end of the third switch is connected to one end of the third resistor; The other end of the first switch, the other end of the second switch and the other end of the third switch are all connected to the first output end of the digital control unit and the output end of the current sensor provided in the double pulse system; The other end of the first resistor, the other end of the second resistor and the other end of the third resistor are all connected to one end of the third capacitor, the inverting input end of the amplifier and the output end of the amplifier; The other end of the third capacitor and the positive input end of the amplifier are both connected to the ground end; The output terminal of the amplifier is connected to the inverting input terminal of the comparison unit.

3. The device according to claim 1, characterized in that The digital control unit is specifically used for: The time threshold signal, the reference current signal and the reference voltage signal are determined according to the current protection threshold, the time protection threshold and a preset mapping table, wherein the mapping table records the correspondence between multiple protection thresholds and the reference signals corresponding to each protection threshold.

4. The device according to claim 1, characterized in that The reference voltage signal includes: a first reference voltage signal and a second reference voltage signal; The voltage adjustment unit is specifically used for: If the driving voltage signal is 1, the generated on-off signal is a first reference voltage signal; If the driving voltage signal is 0, the generated on-off signal is the second reference voltage signal.

5. A protection system, characterized in that: The protection system comprises: the protection device, protection switch device and double pulse test system according to any one of claims 1 to 4 above; The protection switch device includes: a voltage-controlled device; The gate of the voltage-controlled device is connected to the output terminal of the processing unit in the protection device; The source of the voltage-controlled device is connected to one end of the negative electrode of the DC bus in the double-pulse test system; the drain of the voltage-controlled device is connected to the other end of the negative electrode of the DC bus.

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