A method and system for detecting transient protection characteristics of a solid-state power control device

Abstract

The present invention discloses a method and system for detecting the transient protection characteristics of a solid-state power control device, and relates to the field of testing the transient protection characteristics of solid-state power devices. The method includes setting a simulation environment, performing simulation, causing a solid-state power controller circuit simulation model to produce an abnormal operating condition, and obtaining a simulation result; determining the maximum drain-source current and the maximum transient junction-case temperature rise of the main power tube according to the simulation result; judging whether the maximum drain-source current exceeds a first set threshold and whether the maximum transient junction-case temperature rise exceeds a second set threshold; if the maximum drain-source current does not exceed the first set threshold, determining that the solid-state power controller has not experienced an overcurrent failure, and if the maximum transient junction-case temperature rise does not exceed the second set threshold, determining that the solid-state power controller has not experienced a thermal failure, and indicating that the transient protection characteristics of the solid-state power controller are normal. The present invention realizes the detection of the transient protection characteristics of the solid-state power controller under abnormal operating conditions, and will not cause damage to the solid-state power controller.

Description

Technical Field

[0001] The invention relates to the field of transient protection characteristic testing of solid-state power control devices, and in particular to a method and system for detecting transient protection characteristics of solid-state power control devices. Background Art

[0002] Solid-State Power Controller (SSPC) is an intelligent switching device with conversion and protection functions. It has been widely used in aerospace, ships, armored vehicles, unmanned aircraft and other fields, and is a core device in secondary power distribution systems.

[0003] SSPC is generally composed of drive and power switch circuits, control circuits, isolation circuits, overcurrent and short-circuit protection circuits, etc. When an electrical device is overloaded, SSPC can "trip" the line and electrical equipment according to the set overcurrent protection characteristic curve. When a serious overload occurs, it will immediately "trip". This is the transient protection function of SSPC. Transient protection characteristics include tripping characteristics (tripping time and tripping reset time), short-circuit protection time and other transient characteristic parameters. The tripping characteristic parameters mainly detect whether SSPC can quickly respond according to I when a circuit is severely overloaded or short-circuited. 2 The principle of the inverse delay characteristic protection realizes "tripping", cuts off the fault current, protects the electrical load equipment and lines, and should meet the ability that the greater the current, the shorter the disconnection time. The short-circuit protection time describes the shortest time that the SSPC should be immediately shut down when the load current is greater than the current shutdown threshold. As part of the SSPC's own functions, the perfection of the transient protection function also determines the safety and reliability of the SSPC itself and even the entire distribution system.

[0004] In the application of SSPC, abnormal conditions such as overload and load short circuit may occur sometimes. When the overload degree exceeds the tolerable range of SSPC, SSPC may fail. Common short circuit abnormal conditions include opening after load short circuit, load short circuit after opening, short circuit protection, etc. The quality of transient protection characteristic parameters under these abnormal conditions directly determines the reliability level of solid-state power devices in the protection function. It not only reflects the ability to protect the safety of secondary distribution systems, but also is an important characteristic indicator for evaluating the transient protection characteristics and load capacity of solid-state power devices.

[0005] Analyzing the transient protection characteristics under abnormal conditions can analyze the reliability of SSPC under abnormal conditions in advance, which can effectively prevent device failure. At present, the evaluation of SSPC transient protection characteristics is mostly based on normal conditions, that is, testing it under certain conditions, and then analyzing whether the solid-state power control can achieve its protection function according to a specific inverse time protection curve. Testing under abnormal conditions may cause damage to the device. Summary of the invention

[0006] The object of the present invention is to provide a method and system for detecting transient protection characteristics of a solid-state power control device, so as to detect the transient protection characteristics of a solid-state power controller under abnormal working conditions without damaging the solid-state power controller.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] A method for detecting transient protection characteristics of a solid-state power control device, comprising:

[0009] A simulation environment for a solid-state power controller circuit simulation model is set, and the solid-state power controller circuit simulation model is simulated so that the solid-state power controller circuit simulation model generates an abnormal working condition and obtains a simulation result; the solid-state power controller circuit simulation model includes a solid-state power controller electrical simulation model and a solid-state power controller thermal simulation model; the abnormal working condition is a turn-on working condition after a load short circuit, a load short-circuit working condition after turn-on, or a load short-circuit protection working condition; the simulation environment is a simulation environment for generating a turn-on working condition after a load short circuit, a simulation environment for generating a load short-circuit working condition after turn-on, or a simulation environment for generating a load short-circuit protection working condition; the simulation result includes an electrical characteristic curve of the solid-state power controller electrical simulation model under the abnormal working condition and a thermal characteristic curve of the solid-state power controller thermal simulation model under the abnormal working condition; the electrical characteristic curve includes a drain-source current-time curve of a main power tube; the thermal characteristic curve includes a transient junction-shell temperature rise-time curve of the main power tube;

[0010] Determine the maximum drain-source current of the main power tube according to the electrical characteristic curve, and determine the maximum transient junction-case temperature rise of the main power tube according to the thermal characteristic curve;

[0011] Determining whether the maximum drain-source current exceeds a first set threshold, and determining whether the maximum transient junction-case temperature rise exceeds a second set threshold;

[0012] If the maximum drain-source current does not exceed the first set threshold, it is determined that the solid-state power controller has not suffered overcurrent failure, and if the maximum transient junction-case temperature rise does not exceed the second set threshold, it is determined that the solid-state power controller has not suffered thermal failure, which indicates that the transient protection characteristics of the solid-state power controller are normal.

[0013] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0014] The present invention provides a method and system for detecting the transient protection characteristics of a solid-state power control device. By setting a simulation environment of a solid-state power controller circuit simulation model, the solid-state power controller circuit simulation model is simulated, so that the solid-state power controller circuit simulation model produces an abnormal working condition and obtains a simulation result; according to the simulation result, the maximum drain-source current of the main power tube and the maximum transient junction-case temperature rise of the main power tube are determined; it is judged whether the maximum drain-source current exceeds a first set threshold, and it is judged whether the maximum transient junction-case temperature rise exceeds a second set threshold; if the maximum drain-source current does not exceed the first set threshold, it is determined that the solid-state power controller has not suffered an overcurrent failure, and if the maximum transient junction-case temperature rise does not exceed the second set threshold, it is determined that the solid-state power controller has not suffered a thermal failure, which indicates that the transient protection characteristics of the solid-state power controller are normal. The method of the present invention realizes the detection of the transient protection characteristics of the solid-state power controller under abnormal working conditions, and the method of the present invention will not cause damage to the solid-state power controller. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments are briefly introduced below.

[0016] Figure 1 A flow chart of a method for detecting transient protection characteristics of a solid-state power control device provided by the present invention;

[0017] Figure 2 This is a simplified SSPC structural principle block diagram of the present invention;

[0018] Figure 3 This is the SSPC electrical simulation flow chart of the present invention;

[0019] Figure 4 The circuit diagram of the drive module and the power switch module of the present invention;

[0020] Figure 5 This is a circuit diagram of a control module of the present invention;

[0021] Figure 6 This is a circuit diagram of a current detection module of the present invention;

[0022] Figure 7 This is the circuit diagram of the overcurrent and short-circuit protection module of the present invention;

[0023] Figure 8 This is a circuit diagram of a signal conversion module of the present invention;

[0024] Fig. 9 This is the SSPC electrical simulation model diagram of the present invention;

[0025] Fig.10 This is the SSPC thermal simulation flow chart of the present invention;

[0026] Fig.11 A schematic diagram of a Cauer network of the main power tube of the present invention;

[0027] Fig.12 This is a diagram of the SSPC thermal simulation model of the present invention;

[0028] Fig.13 This is a characteristic diagram of the SSPC switch under resistive load of the present invention;

[0029] Fig.14 This is the electrical characteristic diagram of the 400uF capacitor of the present invention when it is turned on;

[0030] Fig.15 This is the thermal characteristic diagram of the 400uF capacitor of the present invention;

[0031] Fig.16 is the overcurrent protection characteristic waveform diagram of the present invention; wherein, Fig.16 (a) is the electrical characteristic waveform of 1.8A overcurrent protection; Fig.16 (b) is the electrical characteristic waveform of 3A overcurrent protection; Fig.16 (c) is the electrical characteristic waveform of 5A overcurrent protection; Fig.16 (d) is the electrical characteristic waveform of 7A overcurrent protection;

[0032] Fig.17 It is a transient protection characteristic waveform diagram under the condition of short-circuit opening resistive load of the present invention; wherein, Fig.17 (a) is the electrical characteristic curve under the condition of short circuit and open resistive load; Fig.17 (b) is the thermal characteristic curve under the condition of short circuit and open resistive load;

[0033] Fig.18 It is a transient protection characteristic waveform diagram under the condition of short-circuit opening capacitive load of the present invention; wherein, Fig.18 (a) is the electrical characteristic curve under the condition of short circuit and capacitive load; Fig.18 (b) is the thermal characteristic curve under short-circuit and capacitive load conditions;

[0034] Fig.19 It is a transient protection characteristic waveform diagram under the condition of short-circuit opening resistance and capacitance load of the present invention; wherein, Fig.19 (a) is the electrical characteristic curve under the condition of short circuit and open resistance and capacitance load; Fig.19 (b) is the thermal characteristic curve under short-circuit and open-resistance and capacitance load conditions;

[0035] Fig. 20 The short circuit generating circuit diagram of the present invention;

[0036] Fig.21 This is a transient protection characteristic waveform diagram under the condition of opening a short-circuit resistive load in the present invention; wherein, Fig.21 (a) is the electrical characteristic curve under the condition of opening short-circuit resistive load; Fig.21 (b) is the thermal characteristic curve under the condition of opening short-circuit resistive load;

[0037] Fig. 22 This is a transient protection characteristic waveform diagram under the condition of opening a short-circuit capacitive load in the present invention; wherein, Fig. 22 (a) is the electrical characteristic curve under the condition of opening short-circuit capacitive load; Fig. 22 (b) is the thermal characteristic curve under the condition of opening short-circuit capacitive load;

[0038] Fig.23 This is a transient protection characteristic waveform diagram of the present invention under the condition of opening a short-circuit resistive-capacitive load; wherein, Fig.23 (a) is the electrical characteristic curve under the condition of opening short-circuit capacitive load; Fig.23 (b) is the thermal characteristic curve under the condition of opening short-circuit capacitive load;

[0039] Fig.24 It is a transient protection characteristic waveform diagram under the short-circuit protection resistive load condition of the present invention; wherein, Fig.24 (a) is the electrical characteristic curve under short-circuit protection resistive load conditions; Fig.24 (b) is the thermal characteristic curve under short circuit protection resistive load conditions;

[0040] Fig.25 It is a transient protection characteristic waveform diagram under the condition of short-circuit protection capacitive load of the present invention; wherein, Fig.25 (a) is the electrical characteristic curve under short-circuit protection capacitive load conditions; Fig.25 (b) is the thermal characteristic curve under short circuit protection capacitive load conditions;

[0041] Fig.26 It is a transient protection characteristic waveform diagram under the condition of short-circuit protection resistive-capacitive load of the present invention; wherein, Fig.26 (a) is the electrical characteristic curve under short-circuit protection resistive-capacitive load conditions; Fig.26 (b) is the thermal characteristic curve under short-circuit protection resistive-capacitive load conditions;

[0042] Fig. 27 A block diagram of a transient protection characteristic detection system for a solid-state power control device provided by the present invention. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0044] The object of the present invention is to provide a method and system for detecting transient protection characteristics of a solid-state power control device, so as to detect the transient protection characteristics of a solid-state power controller under abnormal working conditions without damaging the solid-state power controller.

[0045] The present invention provides a method for evaluating the transient protection characteristics of a solid-state power controller based on an electrothermal simulation model (a method for detecting the transient protection characteristics of a solid-state power control device). The electrothermal model is established and abnormal operating conditions are simulated by means of simulation analysis to analyze whether there is electrical or thermal failure in the transient protection characteristics of the SSPC, thereby overcoming the deficiency in the prior art that detection under abnormal operating conditions may cause damage to the SSPC.

[0046] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0047] Embodiment 1

[0048] like Figure 1 As shown, the method for detecting transient protection characteristics of a solid-state power device provided by the present invention comprises:

[0049] Step 101: Set a simulation environment for a solid-state power controller circuit simulation model, simulate the solid-state power controller circuit simulation model, make the solid-state power controller circuit simulation model produce abnormal working conditions, and obtain simulation results. The solid-state power controller circuit simulation model includes a solid-state power controller electrical simulation model and a solid-state power controller thermal simulation model; the abnormal working condition is a turn-on working condition after a load short circuit, a load short circuit working condition after turn-on, or a load short circuit protection working condition; the simulation environment is a simulation environment for generating a turn-on working condition after a load short circuit, a simulation environment for generating a load short circuit working condition after turn-on, or a simulation environment for generating a load short circuit protection working condition; the simulation results include an electrical characteristic curve of the solid-state power controller electrical simulation model under the abnormal working condition and a thermal characteristic curve of the solid-state power controller thermal simulation model under the abnormal working condition; the electrical characteristic curve includes a drain-source current-time curve of the main power tube; the thermal characteristic curve includes a transient junction-shell temperature rise-time curve of the main power tube.

[0050] Furthermore, the simulation environment for generating the load short-circuit-after-opening condition includes a simulation environment for causing the solid-state power controller electrical simulation model to generate the load short-circuit-after-opening condition and a simulation environment for causing the solid-state power controller thermal simulation model to generate the load short-circuit-after-opening condition. In practical applications, the simulation environment under the load short-circuit-after-opening condition is: in the solid-state power controller electrical simulation model and the solid-state power controller thermal simulation model, wires are used to directly connect the two ends of the load to short-circuit it, and an SSPC opening signal is given to turn on the working circuit.

[0051] The simulation environment for generating the load short-circuit condition after switching on includes a simulation environment for making the solid-state power controller electrical simulation model generate the load short-circuit condition after switching on and a simulation environment for making the solid-state power controller thermal simulation model generate the load short-circuit condition after switching on. In practical applications, the simulation environment under the load short-circuit condition after switching on is: in the solid-state power controller electrical simulation model and the solid-state power controller thermal simulation model, respectively add the following at both ends of the load: Fig. 20 The short circuit generating circuit shown gives the SSPC an opening signal to turn on the working circuit.

[0052] The simulation environment for generating the load short-circuit protection working condition includes a simulation environment for making the solid-state power controller electrical simulation model generate the load short-circuit protection working condition and a simulation environment for making the solid-state power controller thermal simulation model generate the load short-circuit protection working condition. In practical applications, the simulation environment under the load short-circuit protection working condition is: in the solid-state power controller electrical simulation model and the solid-state power controller thermal simulation model, respectively, the working current in the loop exceeds the short-circuit current rated threshold, and the SSPC performs short-circuit protection.

[0053] Furthermore, the electrical characteristic curve also includes a load current-time curve, a load voltage-time curve and a gate-source voltage-time curve of the main power tube. The thermal characteristic curve also includes a power-time curve of the main power tube.

[0054] Furthermore, the process of establishing the solid-state power controller circuit simulation model specifically includes:

[0055] Step 1: Determine the simplified circuit of the solid-state power controller; Figure 2 As shown, the simplified circuit of the solid-state power controller includes a sampling resistor, a load, and a current detection circuit, an overcurrent and short-circuit protection circuit, and a signal conversion circuit (i.e., a signal generating circuit) connected in sequence. Figure 2 a circuit for detecting a tripping signal in the circuit), a control circuit, a drive circuit and a power switch; the power switch is also connected to one end of the sampling resistor; the other end of the sampling resistor is connected to one end of the load; the other end of the load is grounded; the current detection circuit is also respectively connected to both ends of the sampling resistor.

[0056] In practical applications, the specific process of step one is as follows:

[0057] 1. Determine the transient protection characteristic index of the solid-state power controller. The operating voltage of the SSPC circuit loop is 28V, and its turn-on time and turn-off time are both within 5ms. The short-circuit protection current is 1200%×1A, that is, when the current flowing through the SSPC is greater than 12A, the transient short-circuit protection function of the SSPC is immediately triggered, and the circuit breaker trips within 100us. The tripping time varies according to the overcurrent load, as shown in Table 1.

[0058] Table 1 SSPC overcurrent protection index table

[0059]

[0060] 2. Determine the parameters of the main power tube of SSPC. The gate-source drive voltage of the main power tube Z-MOSFET selected by SSPC is 10V, and the threshold voltage is 2~4V. According to the working environment of SSPC and the derating of the main power tube, the maximum transient junction-case temperature rise of this main power tube is 50℃. If the temperature rise exceeds this value, the SSPC may fail due to overheating.

[0061] 3. SSPC function analysis: The current SSPC has functions such as slow opening and slow closing, short-circuit protection, and inverse time overcurrent protection. It focuses on the transient protection function and transient protection characteristics of SSPC, and simplifies the structure into drive module, power switch module, control module, overcurrent and short-circuit protection circuit, and signal conversion module.

[0062] Based on the indicators, circuit structure and principle in step 1, the present invention uses Saber software for modeling and simulation. The establishment of the solid-state power controller circuit simulation model using Saber software and the simulation process are as follows: Figure 3 shown.

[0063] Step 2: Draw an electrical simulation model of the solid-state power controller according to the simplified circuit of the solid-state power controller. Specifically, based on the simplified circuit structure and working principle of the solid-state power controller, component parameter analysis and circuit modeling are performed on different functional modules respectively, and each module is connected into a complete electrical simulation model of the solid-state power controller through digital logic elements.

[0064] The electrical simulation model of the solid-state power controller includes a first sampling resistor, a first load, and a first current detection module, a first overcurrent and short circuit protection module, a first signal conversion module, a first control module, a first drive module, and a first power switch module connected in sequence. The first power switch module is also connected to one end of the first sampling resistor; the other end of the first sampling resistor is connected to one end of the first load; the other end of the first load is grounded. The first current detection module is also connected to both ends of the first sampling resistor.

[0065] In practical applications, first of all, the drive module and the power switch module are modeled. In order to reduce the transient impact of the SSPC during the switching process, the main power tube Z-MOSFET device is equipped with a drive circuit with slow turn-on and slow turn-off effects. The circuit design is as follows: Figure 4 shown.

[0066] Figure 4 Where shunt is the sampling resistor, which is used to collect loop current information, and its value is 0.1Ω; Load is the loop load, and Z-MOSFET is the main power tube; C gd is the gate-drain capacitance, C gs is the gate-source capacitance, C ds is the drain-source capacitance, R g is the gate resistance. The turn-on delay of SSPC is t d(on) , which is calculated as shown in formula (1).

[0067]

[0068] Among them, U g is the gate-source voltage of Z-MOSFET, U T is the Z-MOSFET turn-on threshold voltage, time constant τ i As shown in formula (2):

[0069] τ i =R g C iss (2)

[0070] When the Z-MOSFET operates in the resistance region or the cut-off region, there is formula (3):

[0071] C iss =C gs +C gd (3)

[0072] Table 2 SSPC on-off time index table

[0073]

[0074] According to the turn-on and turn-off time indicators in Table 2, the final C is calculated by equations (1), (2) and (3): gs and C gd Both are 0.3uF.

[0075] Then, the control module is modeled. The output terminal Q of the D flip-flop in the control circuit provides the gate-source voltage V for the Z-MOSFET after passing through the voltage amplifier circuit composed of the operational amplifier F. gsTherefore, when Q output is high, the power switch is turned on; when Q output is low, the power circuit is disconnected. The electrical model established by the drive and control parts can be seen in Figure 5 Among them, the S and D of the D flip-flop are always connected to high level, and the logical true values ​​of each output are shown in Table 3, 1 represents high level, and 0 represents low level.

[0076] Table 3 Control circuit logic truth table

[0077]

[0078] Finally, the overcurrent and short-circuit protection module is modeled. The overcurrent and short-circuit protection module is connected to the power switch module through the current detection module, so the current detection module needs to be established first. The source of the main power tube Z-MOSFET in the established SSPC circuit simulation model needs to be grounded to ensure the stability of the gate-source voltage. A high-end current detection circuit is used. The circuit schematic diagram is as follows: Figure 6 As shown, R1 = R2, R3 = R4, and the output voltage of the high-end current detection circuit is U o , the current flowing through the sampling resistor shunt is I, and the relationship between them is shown in formula (4):

[0079] I=U o *R1 / (R4*R shunt ) (4)

[0080] Among them, the resistance of the sampling resistor shunt is 0.1Ω, the resistance of R1 is 1kΩ, and the resistance of R4 is 10kΩ. In this case, the working current I and the output voltage U o The ratio is 1:1, that is, the output voltage corresponding to the working current of 1A is 1V.

[0081] According to the SSPC overcurrent protection index, the extreme inverse time equation is determined as:

[0082]

[0083] Use the inverse proportional curve fitting method to establish the overcurrent and short-circuit protection modules of the target SSPC, such as Figure 7 As shown, where R1=R2, C1=C2, R3=R4, C3=C4.

[0084] The delayed tripping of overcurrent protection relies on the voltage delay input of two differential integration circuits. Assuming the delay of OP1 is t1 and the delay of OP2 is t2, the calculation formula is as follows:

[0085]

[0086]

[0087] Taking the calculation result of the extreme inverse time equation as the standard, the simultaneous equations (6) and (7) calculate that the values ​​of the resistor and capacitor components in the overcurrent and short-circuit protection module are R1=R2=100kΩ, R3=R4=10kΩ, C1=C2=3.5uF, C3=C4=1.7uF. At this time, the overcurrent and short-circuit protection module can better fit the overcurrent protection curve and tripping time requirements of the target SSPC. The output result of the overcurrent and short-circuit protection module is a logic level signal. The tripping signal to be connected in the control circuit should be a voltage signal. To ensure circuit simulation, a signal conversion module is added between the overcurrent and short-circuit protection module and the control circuit, such as Figure 8 shown.

[0088] Integrating the above functional circuit modules, the electrical simulation model of the solid-state power controller is obtained as follows: Fig. 9 shown.

[0089] Step 3: Establish a third-order Cauer network.

[0090] Step 4: Combine the simplified circuit of the solid-state power controller with the third-order Cauer network to obtain a thermal simulation model of the solid-state power controller. Specifically, the transient thermal resistance curve of the SSPC main power tube is used to extract the thermal resistance and thermal capacitance parameters, and an equivalent thermal circuit model (third-order Cauer network) of the main power tube MOSFET device is established, and combined with the peripheral circuit to obtain a thermal simulation model of the solid-state power controller.

[0091] The thermal simulation model of the solid-state power controller includes a second sampling resistor, a second load, a voltage-current conversion module, a third-order Cauer network, and a second current detection module, a second overcurrent and short-circuit protection module, a second signal conversion module, a second control module, a second drive module, and a second power switch module connected in sequence.

[0092] The second power switch module is also connected to one end of the second sampling resistor; the other end of the second sampling resistor is connected to one end of the second load; the other end of the second load is grounded. The second current detection module is also connected to both ends of the second sampling resistor respectively. The third-order Cauer network is connected to the second power switch module through the voltage-current conversion module. The voltage-current conversion module includes a current converter, a voltage converter and a power calculator.

[0093] In practical applications, Saber software is used to model and simulate the thermal simulation model. The process is as follows: Fig.10 shown.

[0094] A thermal resistance and heat capacitance network (i.e. Cauer network) composed of RC units is used. Since the main power tube is the main heat-generating device, and each R in the Cauer network th -Cth The structures all correspond to the actual physical layer of the device, so the third-order Cauer network is sufficient to simulate the thermal characteristics of the main power tube. The Cauer network of the main power tube is established as follows: Fig.11 As shown, where T j Represents the junction temperature of the main power tube MOSFET, T c represents the case temperature of the main power tube MOSFET, and P represents the actual driving power of the main power tube MOSFET.

[0095] By combining the third-order Cauer network with the peripheral circuit (simplified circuit of the solid-state power controller), a complete thermal simulation model of the solid-state power controller can be obtained, such as Fig.12 The peripheral circuit is responsible for simulating the circuit response of SSPC under various working conditions. The voltage-current conversion module extracts power parameters from the peripheral circuit and inputs them into the Z-MOSFET thermal circuit model (third-order Cauer network). The transient temperature response result is simulated by the Z-MOSFET thermal circuit model.

[0096] In practical applications, after obtaining the solid-state power control electrical simulation model and the solid-state power controller thermal simulation model, the correctness of the two needs to be verified, as follows:

[0097] 1. Electrical simulation verification of switching characteristics

[0098] The results are as follows Fig.13 Shown: From Fig.13 It can be seen that the SSPC turn-on time is about 1ms and the turn-off time is about 3.6ms, which meets the target SSPC requirements.

[0099] 2. Electrical simulation verification of maximum capacitance

[0100] It is known that the short-circuit current threshold of the SSPC built by the present invention is 12A, and the turn-on time under resistive load is 1ms. Based on this, the maximum capacitance of the SSPC is estimated from the perspective of the transient maximum current. The capacitance current calculation is shown in formula (8):

[0101]

[0102] In formula (8), I c is the current flowing through the capacitive load, its value should be less than 12A, C is the capacitance of the capacitive load, u c is the voltage across the capacitive load. The SSPC turn-on time is 1ms, which can be regarded as u c From 0 to 28V, the estimated capacitance value of the capacitive load is C<428.6uF. Therefore, a capacitive load with a capacitance value of 400uF is selected to simulate the capacitive load turn-on characteristics of SSPC, and the waveform is as follows Fig.14As shown, from top to bottom are load current, load voltage, Z-MOSFET gate-source voltage, and Z-MOSFET drain-source current (drain-source current of the main power tube).

[0103] Depend on Fig.14 It can be seen that when the capacitive load is turned on, there is a surge current in the SSPC, and the maximum current is about 7.16A, which will not trigger the SSPC short-circuit protection. The gate-source voltage of the Z-MOSFET is always 10V, indicating that the SSPC is always in the on state and the protection circuit is not activated. After about 2.3ms, the load capacitor is fully charged, the current in the power switch module is 0, and the voltage across the load capacitor is equal to the operating voltage of 28V.

[0104] 3. Solid-state power controller thermal simulation model verification

[0105] By comparing the theoretical calculation results and simulation results of the average temperature rise of the main power tube during the capacitive load opening process, the correctness of the thermal simulation model of the solid-state power controller constructed by the present invention is verified. The average temperature rise of the power tube when the capacitive load is turned on can be expressed by formula (9):

[0106]

[0107] Where k is the proportional constant; C is the capacitive load capacitance, V is the operating voltage, t on is the turn-on time. If the capacitive load of the SSPC is 400uF, the temperature rise can be calculated to be ΔT = 21.82°C.

[0108] When the load of the SSPC is 400uF, the temperature rise of the main power tube obtained by the thermal simulation model of the solid-state power controller during the opening process is as follows Fig.15 As shown, Fig.15 From top to bottom in the figure are the integral of the temperature rise of the main power tube over time, the transient power of the main power tube, and the transient temperature rise of the main power tube. Fig.15 It can be seen that when the 400uF capacitor is turned on, the maximum transient temperature rise of the main power tube is 32.953℃. The average temperature rise of the main power tube during the 0-1ms process ΔT 仿真 =19.55℃, which is close to the theoretically calculated value of 21.82℃, thus verifying the correctness of the established SSPC thermal simulation model.

[0109] 4. Verification of inverse time overcurrent protection curve

[0110] Referring to the target SSPC tripping time requirements in Table 1, 1.8 times overload current, 3 times overload current, 5 times overload current and 7 times overload current were selected for simulation. The simulation results are shown in Figure 1. Fig.16 shown. Fig.16The waveforms in are load voltage, load current, Z-MOSFET gate-source voltage, and Z-MOSFET drain-source current from top to bottom. The comparison between the simulation results and the target SSPC trip time requirements and theoretical calculation results is shown in Table 4. The trip time requirements of the target SSPC are met, verifying the correctness of the electrothermal simulation of the transient protection function of the SSPC simulation model.

[0111] Table 4 Simulation results comparison table

[0112] Load resistance Overcurrent multiple Theoretical calculation results Simulation Results 15.56Ω 1.8 1.339s 1.333s 9.33Ω 3 0.375s 0.540s 5.6Ω 5 0.125s 0.127s 4Ω 7 0.063s 0.067s

[0113] Step 102: determining a maximum drain-source current of the main power tube according to the electrical characteristic curve, and determining a maximum transient junction-case temperature rise of the main power tube according to the thermal characteristic curve.

[0114] Step 103: Determine whether the maximum drain-source current exceeds a first set threshold, and determine whether the maximum transient junction-case temperature rise exceeds a second set threshold.

[0115] Step 104: If the maximum drain-source current does not exceed the first set threshold, it is determined that the solid-state power controller has not suffered overcurrent failure, and if the maximum transient junction-case temperature rise does not exceed the second set threshold, it is determined that the solid-state power controller has not suffered thermal failure, which indicates that the transient protection characteristics of the solid-state power controller are normal.

[0116] After the verification is completed, the transient protection characteristics of SSPC under abnormal conditions are analyzed to determine the electrical and thermal failure of SSPC under abnormal conditions, as follows:

[0117] 1. Under the conditions of resistive load, capacitive load and resistive-capacitive load, the transient protection electrothermal characteristics of SSPC under the abnormal working condition of "short circuit opening" (opening after load short circuit) are analyzed. The electrical characteristic curve and thermal characteristic curve are shown in Figure 17 to Figure 19 As shown, the electrical characteristic curve includes load voltage, load current, Z-MOSFET gate-source voltage and Z-MOSFET drain-source current; the thermal characteristic curve includes Z-MOSFET power and Z-MOSFET junction-case temperature rise (junction-case temperature rise of the main power tube). Figure 17 to Figure 19 It can be seen that the drain-source current waveform of the main power tube of SSPC shows a peak in the short-circuit opening condition, and the drain-source current of the main power tube shows a trend of abrupt rise and then abrupt fall. In addition, the gate-source voltage of Z-MOSFET drops to 0 at the moment when the current in the loop reaches 12A, so that SSPC can achieve instantaneous short-circuit trip protection.

[0118] The analysis shows that the transient protection characteristics of SSPC under short-circuit opening conditions have nothing to do with the type of load in the circuit. The current and voltage in the load are both 0, the tripping time is within 100us, and the protection circuit reacts very quickly. The maximum drain-source current of the main power tube does not exceed the maximum pulse leakage current value of the main power tube (the first set threshold), and the SSPC will not fail due to overcurrent; the maximum transient junction-case temperature rise of the power tube is around 46.6℃, which does not exceed the maximum junction-case temperature rise specified for the main power tube (the second set threshold), and the SSPC will not fail due to overheating.

[0119] 2. Under the conditions of resistive load, capacitive load and resistive-capacitive load, the transient protection characteristics of SSPC under the abnormal working condition of "open short circuit" (load short circuit after opening) are analyzed. By adding the following at both ends of the load: Fig. 20 The short-circuit generating circuit shown in the figure gives the SSPC an on signal to turn on the working circuit; the short-circuit generating circuit parameters are set so that the load short-circuits 2s after the SSPC is turned on; the step is set to 0.01ms, and the simulation result waveform is as follows Figure 21 to Figure 23 The electrical characteristic curve diagram includes the load voltage-time curve, the load current-time curve, the Z-MOSFET gate-source voltage-time curve and the Z-MOSFET drain-source current-time curve; the thermal characteristic curve diagram includes the Z-MOSFET power-time curve and the Z-MOSFET transient junction-case temperature rise-time curve.

[0120] from Figure 21 to Figure 23 It can be seen that the drain-source current curve of the main power tube in the SSPC short-circuit condition shows a trend of vertical rise and then slow decline. When the drain-source current of the main power tube in the loop rises vertically to the maximum value, the gate-source voltage of the Z-MOSFET immediately drops to 0, achieving instantaneous short-circuit trip protection.

[0121] Under the condition of resistive and capacitive load, the voltage of the load capacitor of SSPC rises from 0V to 28V in the "open short circuit" condition, and the current of the load resistor drops from 1A to 0A. The maximum drain-source current of the main power tube exceeds 40A, which does not exceed the maximum pulse leakage current value of the main power tube, and the SSPC will not fail due to overcurrent; the maximum transient junction-case temperature rise of the main power tube is about 43℃, which does not exceed the specified maximum junction-case temperature rise of the main power tube, and the SSPC will not fail due to overheating.

[0122] 3. Under the conditions of resistive load, capacitive load and resistive-capacitive load, the transient protection characteristics of SSPC under the abnormal working condition of "short circuit protection" are simulated and analyzed. The simulation results are as follows: Figure 24 to Figure 26As shown. From the simulation results, the drain-source current-time curve of the main power tube of SSPC under short-circuit protection is similar to that of "short-circuit opening", with spikes, and the drain-source current of the main power tube shows a trend of rising sharply and then falling sharply. Similarly, when the drain-source current of the main power tube in the loop reaches 12A, the gate-source voltage of Z-MOSFET immediately drops to 0, achieving instantaneous short-circuit tripping protection. The transient protection characteristics of SSPC under short-circuit protection conditions are related to the type of load in the loop. When the short-circuit protection function is triggered, its tripping time is less than 100us, and the protection circuit reacts very quickly. The maximum drain-source current of the main power tube is around 12.01A, which does not exceed the maximum pulse leakage current value of the main power tube, and the SSPC will not fail due to overcurrent; when the load is a resistive load, the maximum transient junction-case temperature rise of the main power tube is around 25.7°C; when the load is a capacitive load or a resistive-capacitive load, the maximum transient junction-case temperature rise of the main power tube is around 46.7°C. The maximum transient junction-case temperature rise of the main power tube under such working conditions does not exceed the specified maximum junction-case temperature rise of the main power tube, and the SSPC will not fail due to overheating.

[0123] The advantages and positive effects of the present invention are:

[0124] (1) Based on the simplified modification of the functional structure of a typical SSPC, a SSPC circuit simulation model was established. While not losing key parameters, it is close to the actual situation and has a certain degree of universality. (2) While conducting simulation analysis, theoretical calculation comparisons were carried out to further verify the correctness of the model. (3) The analysis process is closely combined with various parameter graphs, which is clear and intuitive.

[0125] Embodiment 2

[0126] In order to execute the method corresponding to the above embodiment 1 to achieve the corresponding functions and technical effects, a transient protection characteristic detection system for a solid-state power control device is provided below, such as Fig. 27 As shown, including:

[0127] The simulation module 2701 is used to set the simulation environment of the solid-state power controller circuit simulation model, simulate the solid-state power controller circuit simulation model, make the solid-state power controller circuit simulation model produce abnormal working conditions, and obtain simulation results. The solid-state power controller circuit simulation model includes a solid-state power controller electrical simulation model and a solid-state power controller thermal simulation model; the abnormal working condition is a load short-circuit after opening working condition, a load short-circuit working condition after opening, or a load short-circuit protection working condition; the simulation environment is a simulation environment for generating a load short-circuit after opening working condition, a simulation environment for generating a load short-circuit after opening working condition, or a simulation environment for generating a load short-circuit protection working condition; the simulation results include the electrical characteristic curve of the solid-state power controller electrical simulation model under the abnormal working condition and the thermal characteristic curve of the solid-state power controller thermal simulation model under the abnormal working condition; the electrical characteristic curve includes the drain-source current-time curve of the main power tube; the thermal characteristic curve includes the transient junction-shell temperature rise-time curve of the main power tube.

[0128] The characteristic parameter determination module 2702 is used to determine the maximum drain-source current of the main power tube according to the electrical characteristic curve, and to determine the maximum transient junction-case temperature rise of the main power tube according to the thermal characteristic curve.

[0129] The judgment module 2703 is used to judge whether the maximum drain-source current exceeds a first set threshold, and to judge whether the maximum transient junction-case temperature rise exceeds a second set threshold.

[0130] The detection result output module 2704 is used to determine that the solid-state power controller has not suffered overcurrent failure if the maximum drain-source current does not exceed the first set threshold, and to determine that the solid-state power controller has not suffered thermal failure if the maximum transient junction-case temperature rise does not exceed the second set threshold, indicating that the transient protection characteristics of the solid-state power controller are normal.

[0131] Embodiment 3

[0132] The present invention also provides an electronic device, comprising: a memory and a processor, wherein the memory is used to store a computer program, and the processor runs the computer program to enable the electronic device to execute the method for detecting transient protection characteristics of a solid-state power control device of embodiment 1.

[0133] Embodiment 4

[0134] The present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method for detecting transient protection characteristics of a solid-state power control device of the first embodiment is implemented.

[0135] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0136] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for detecting transient protection characteristics of a solid-state power control device, It is characterized in that include: A simulation environment for a solid-state power controller circuit simulation model is set, and the solid-state power controller circuit simulation model is simulated so that the solid-state power controller circuit simulation model generates an abnormal working condition and obtains a simulation result; the solid-state power controller circuit simulation model includes a solid-state power controller electrical simulation model and a solid-state power controller thermal simulation model; the abnormal working condition is a turn-on working condition after a load short circuit, a load short-circuit working condition after turn-on, or a load short-circuit protection working condition; the simulation environment is a simulation environment for generating a turn-on working condition after a load short circuit, a simulation environment for generating a load short-circuit working condition after turn-on, or a simulation environment for generating a load short-circuit protection working condition; the simulation result includes an electrical characteristic curve of the solid-state power controller electrical simulation model under the abnormal working condition and a thermal characteristic curve of the solid-state power controller thermal simulation model under the abnormal working condition; the electrical characteristic curve includes a drain-source current-time curve of a main power tube; the thermal characteristic curve includes a transient junction-shell temperature rise-time curve of the main power tube; Determine the maximum drain-source current of the main power tube according to the electrical characteristic curve, and determine the maximum transient junction-case temperature rise of the main power tube according to the thermal characteristic curve; Determining whether the maximum drain-source current exceeds a first set threshold, and determining whether the maximum transient junction-case temperature rise exceeds a second set threshold; If the maximum drain-source current does not exceed the first set threshold, it is determined that the solid-state power controller has not suffered overcurrent failure, and if the maximum transient junction-case temperature rise does not exceed the second set threshold, it is determined that the solid-state power controller has not suffered thermal failure, which indicates that the transient protection characteristics of the solid-state power controller are normal.

2. The method for detecting transient protection characteristics of a solid-state power control device according to claim 1, It is characterized in that The process of establishing the solid-state power controller circuit simulation model specifically includes: Determine the simplified circuit of a solid-state power controller; Drawing a solid-state power controller electrical simulation model according to a simplified circuit of the solid-state power controller; Establish a third-order Cauer network; The simplified circuit of the solid-state power controller is combined with the third-order Cauer network to obtain a thermal simulation model of the solid-state power controller.

3. The method for detecting transient protection characteristics of a solid-state power control device according to claim 1, It is characterized in that The electrical simulation model of the solid-state power controller includes a first sampling resistor, a first load, and a first current detection module, a first overcurrent and short-circuit protection module, a first signal conversion module, a first control module, a first drive module, and a first power switch module connected in sequence; The first power switch module is also connected to one end of the first sampling resistor; the other end of the first sampling resistor is connected to one end of the first load; the other end of the first load is grounded; The first current detection module is also connected to two ends of the first sampling resistor respectively.

4. The method for detecting transient protection characteristics of a solid-state power control device according to claim 1, It is characterized in that The solid-state power controller thermal simulation model includes a second sampling resistor, a second load, a voltage-current conversion module, a third-order Cauer network, and a second current detection module, a second overcurrent and short-circuit protection module, a second signal conversion module, a second control module, a second drive module, and a second power switch module connected in sequence; The second power switch module is also connected to one end of the second sampling resistor; the other end of the second sampling resistor is connected to one end of the second load; the other end of the second load is grounded; The second current detection module is also connected to both ends of the second sampling resistor respectively; The third-order Cauer network is connected to the second power switch module through the voltage-current conversion module.

5. The method for detecting transient protection characteristics of a solid-state power control device according to claim 1, It is characterized in that The simulation environment for generating the open-on working condition after a load short circuit includes a simulation environment for causing the solid-state power controller electrical simulation model to generate the open-on working condition after a load short circuit and a simulation environment for causing the solid-state power controller thermal simulation model to generate the open-on working condition after a load short circuit; The simulation environment for generating the load short-circuit working condition after switching on includes a simulation environment for making the electrical simulation model of the solid-state power controller generate the load short-circuit working condition after switching on and a simulation environment for making the thermal simulation model of the solid-state power controller generate the load short-circuit working condition after switching on; The simulation environment for generating load short-circuit protection working conditions includes a simulation environment for enabling a solid-state power controller electrical simulation model to generate load short-circuit protection working conditions and a simulation environment for enabling a solid-state power controller thermal simulation model to generate load short-circuit protection working conditions.

6. The method for detecting transient protection characteristics of a solid-state power control device according to claim 1, It is characterized in that The electrical characteristic curve also includes a load current-time curve, a load voltage-time curve and a gate-source voltage-time curve of the main power tube.

7. The method for detecting transient protection characteristics of a solid-state power control device according to claim 1, It is characterized in that The thermal characteristic curve also includes a power-time curve of the main power tube.

8. A transient protection characteristic detection system for solid-state power control devices, It is characterized in that include: A simulation module, used to set a simulation environment of a solid-state power controller circuit simulation model, simulate the solid-state power controller circuit simulation model, make the solid-state power controller circuit simulation model produce abnormal working conditions, and obtain simulation results; the solid-state power controller circuit simulation model includes a solid-state power controller electrical simulation model and a solid-state power controller thermal simulation model; the abnormal working condition is a turn-on working condition after a load short circuit, a load short-circuit working condition after turn-on, or a load short-circuit protection working condition; the simulation environment is a simulation environment for generating a turn-on working condition after a load short circuit, a simulation environment for generating a load short-circuit working condition after turn-on, or a simulation environment for generating a load short-circuit protection working condition; the simulation results include an electrical characteristic curve of the solid-state power controller electrical simulation model under the abnormal working condition and a thermal characteristic curve of the solid-state power controller thermal simulation model under the abnormal working condition; the electrical characteristic curve includes a drain-source current-time curve of a main power tube; the thermal characteristic curve includes a transient junction-shell temperature rise-time curve of the main power tube; A characteristic parameter determination module, used to determine the maximum drain-source current of the main power tube according to the electrical characteristic curve, and to determine the maximum transient junction-case temperature rise of the main power tube according to the thermal characteristic curve; A judgment module, used to judge whether the maximum drain-source current exceeds a first set threshold, and to judge whether the maximum transient junction-case temperature rise exceeds a second set threshold; The detection result output module is used to determine that the solid-state power controller has not suffered overcurrent failure if the maximum drain-source current does not exceed the first set threshold, and to determine that the solid-state power controller has not suffered thermal failure if the maximum transient junction-case temperature rise does not exceed the second set threshold, indicating that the transient protection characteristics of the solid-state power controller are normal.

9. An electronic device, It is characterized in that include: A memory and a processor, wherein the memory is used to store a computer program, and the processor runs the computer program to enable the electronic device to execute the method for detecting transient protection characteristics of a solid-state power control device according to any one of claims 1 to 7.

10. A computer-readable storage medium, It is characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method for detecting transient protection characteristics of a solid-state power control device according to any one of claims 1 to 7 is implemented.

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