Modeling method of heterogeneous hybrid device switch transient state full-stage behavior model

Abstract

The invention provides a modeling method of a heterogeneous hybrid device switch transient full-stage behavior model, which divides the switch transient full stage of a heterogeneous hybrid device into 11 stages according to the state of the device, analyzes the working principle of the heterogeneous hybrid device in each stage in detail, and combines the physical characteristics of the device to obtain the behavior model of the heterogeneous hybrid device switch transient full-stage behavior model. Under the consideration of the influence of the junction temperature and parasitic parameters introduced by the device and the circuit layout, transient mathematical expressions of the current flowing through the MOSFET, the current flowing through the IGBT and the voltage drop at the two ends of the hybrid device in different stages and the duration expressions of all the stages are deduced, and voltage and current curve modeling of the heterogeneous hybrid device is completed. A loss mathematical expression of the hybrid device in each stage is deduced by combining the established expressions of the voltage, the current and the duration of each stage, and the voltage, the current and the loss are combined, so that a switch transient full-stage behavior model for the heterogeneous hybrid device is established, and a theoretical foundation is laid for popularization and application of the hybrid device.

Description

Technical Field

[0001] The present application relates to the field of electronic technologies, and particularly to a method for modeling the switching transient full-stage behavior model of a heterogeneous hybrid device. Background Art

[0002] In practical applications, power devices need to establish transient models of voltage and current curves because the switching transient process directly determines the switching losses, efficiency, and heating conditions of the devices. Through accurate modeling, the variation laws of voltage and current during the switching process can be analyzed in depth, thereby optimizing device design and driving strategies, reducing losses, and improving system efficiency. Therefore, the transient modeling of power devices is the basis for the design, optimization, and reliable operation of power electronic systems, and is of great significance for improving efficiency, reducing costs, extending device life, and promoting technological progress.

[0003] A heterogeneous hybrid device composed of a parallel connection of SiC MOSFET and Si IGBT has the advantages of both low cost and high performance. However, there are two deficiencies in the current research on modeling the voltage and current curves during the transient and steady-state processes of heterogeneous hybrid devices: one is that the mathematical expressions of the voltages and currents of MOSFET and IGBT in each stage cannot be accurately given; the other is that its loss model mainly relies on data fitting rather than calculating based on the characteristics of the voltage and current curves during the switching transient process, resulting in a large limitation of its applicable range by device models and test environments. Summary of the Invention

[0004] In order to overcome the above technical defects, the present application provides a method for modeling the switching transient full-stage behavior model of a heterogeneous hybrid device. To achieve the above object, the present application is implemented according to the following technical solutions:

[0005] The present application provides a method for modeling the switching transient full-stage behavior model of a heterogeneous hybrid device, characterized by including:

[0006] Obtain the first voltage and current curves of the heterogeneous hybrid device during the turn-on process;

[0007] Based on the first voltage and current curves, determine the first partial loss model of the heterogeneous hybrid device during the turn-on process;

[0008] Obtain the second voltage and current curves of the heterogeneous hybrid device during the conduction process;

[0009] Based on the second voltage and current curves, determine the second partial loss model of the heterogeneous hybrid device during the conduction process;

[0010] Obtain the third voltage and current curves of the heterogeneous hybrid device during the turn-off process;

[0011] Determining a third partial loss model of the heterogeneous hybrid device during a turn-off process based on the second voltage and current curve;

[0012] Constructing a voltage and current curve transient model of the heterogeneous hybrid device based on the first voltage and current curve, the second voltage and current curve, and the third voltage and current curve;

[0013] Constructing a complete loss model of the heterogeneous hybrid device based on the first partial loss model, the second partial loss model, and the third partial loss model;

[0014] Based on the voltage and current curve transient model of the heterogeneous hybrid device and the complete loss model of the heterogeneous hybrid device, a switching transient full-stage behavior model of the heterogeneous hybrid device is determined.

[0015] Optionally, the process of constructing the first voltage and current curve and determining a first partial loss model of the heterogeneous hybrid device during a turn-on process based on the first voltage and current curve includes:

[0016] Phase 1 (t0-t1): At t0, the driving voltage is applied to the input capacitor C of the Si IGBT. ies and the input capacitance C of the SiC MOSFET iss Charging (C iss =C gd +C gs 、C ies =C ge +C gc , C gd 、C gs They are the gate-drain capacitance and gate-source capacitance of SiC MOSFET, C gc 、C ge are the gate-collector capacitance and gate-emitter capacitance of Si IGBT, respectively, and the gate-source voltage V GS The first expression is related to the gate-emitter voltage V GE The second expression is as follows:

[0017]

[0018] Where, e is the time constant, V Mon With V Moff They are the positive driving voltage and negative driving voltage of SiC MOSFET, V Ton With V Toff They are the positive driving voltage and negative driving voltage of Si IGBT respectively. M With τ T are the charging constants of SiC MOSFET and Si IGBT respectively, where τ M =Rgm C iss 、 τ T = R gt C ies ; R gm is the gate resistance of the SiC MOSFET, and R gt is the gate resistance of the Si IGBT; t represents time;

[0019] In the first stage, neither V GS nor V GE reaches the threshold voltage V THM of the MOSFET and the threshold voltage V THT of the IGBT. The current MOSFET and the current IGBT both remain in the off state, and the drain current I D and the collector current I C are always zero, and the drain-source voltage V DS remains at the DC bus voltage V DC . The first turn-on loss of the heterogeneous hybrid type in this stage is zero, and the duration of this stage is:

[0020]

[0021] Second stage (t1 - t2): At time t1, V GS rises to the gate threshold voltage V THM of the MOSFET, I D gradually rises, V GS and V GE continue to increase. The expression of V GS is the first expression, and the expression of V GE is the second expression. The MOSFET is in the amplification region at this time. According to the characteristics of the power device amplification region, the first I D expression is as follows:

[0022] I D (t) = g fs (V GS (t) - V THM )

[0023] where g fs is the transconductance of the MOSFET;

[0024] In the second stage, the IGBT is not turned on, I C remains zero, and the current I p flowing through the hybrid device changes rapidly, acting on the circuit stray inductance resulting in a slight decrease in V DS but still close to V DC ; According to the first expressions of V GS and V GE , ID , I C The initial time difference when starting to rise is:

[0025]

[0026] In the second stage, the loss E of the MOSFET on_MOS , the loss E of the IGBT on_IGBT and the second turn-on loss E of the heterogeneous hybrid device on (t1, t2) can be approximated as:

[0027]

[0028] E on_IGBT (t1, t2) = 0

[0029] E on (t1, t2) = E on_MOS (t1, t2)

[0030] The third stage (t2 - t3): At time t2, V GE rises to the IGBT gate threshold voltage V THT , I C gradually rises, V GS and V GE continue to increase. The first I C expression is as follows:

[0031] I C (t) = g fe (V GE (t) - V THT )

[0032] where g fe is the transconductance of the IGBT;

[0033] In the third stage, the change rate of the first I D in this stage, the change rate of the first I C can be expressed as:

[0034]

[0035] In the formula, L s is the source line parasitic inductance, L e is the emitter line parasitic inductance;

[0036] At time t3, all the load current transfers to the hybrid device branch, and I P continues to increase to its peak I peak , and the expression of I peak is:

[0037]

[0038] Wherein, Q rr1 is the reverse recovery charge of the MOSFET, and Q rr2 is the reverse recovery charge of the IGBT;

[0039] The expression of the peak current and time is:

[0040]

[0041] Based on the first I D change rate, the first I C change rate, the I peak expression, and the expression of the peak current and time, determine the peak current I Dpon of the MOSFET during the turn-on process, and the peak current I Cpon of the IGBT during the turn-on process. The expressions are as follows:

[0042]

[0043] In the third stage, the loss E on_MOS (t2, t3) of the MOSFET, the loss E on_IGBT (t2, t3) of the IGBT, and the third turn-on loss E on (t2, t3) of the heterogeneous hybrid device can be approximated as:

[0044]

[0045] E on (t2, t3) = E on_MOS (t2, t3) + E on_IGBT (t2, t3)

[0046] Fourth stage (t3 - t4): I P reaches the peak I peak , and then gradually recovers to the load current I L . V GS and V GE enter the Miller plateau and remain at the plateau voltage V GPM1 and V GPT1 unchanged. The drive circuit only charges C gd and C ge , which leads to a significant drop in V DS . The change rate of V DS can be expressed as:

[0047]

[0048] V DS The expression of the time required for the drop is as follows:

[0049]

[0050] Wherein, V on is the conduction voltage drop of the heterogeneous hybrid device;

[0051] In the fourth stage, the fourth turn-on loss E on (t3, t4) of the heterogeneous hybrid device can be approximately expressed as:

[0052]

[0053] Fifth stage (t4 - t5): The Miller plateau ends, and V GS and V GE continue to rise. At this time, both the IGBT and the MOSFET are in the variable resistance region, and the commutation process is completed according to the magnitude of the on-resistance of the two. A steady state is reached at time t5; at this time, the fifth turn-on loss E on (t4, t5) of the heterogeneous hybrid device can be approximately expressed as:

[0054] E on (t4, t5) = V on I L (t5 - t4)

[0055] Based on the first turn-on loss, the second turn-on loss, the third turn-on loss, the fourth turn-on loss, and the fifth turn-on loss, the first overall loss model of the heterogeneous hybrid device during the turn-on process is determined as follows:

[0056] E on = E on (t1, t2) + E on (t2, t3) + E on (t3, t4) + E on (t4, t5)

[0057] Wherein, E on represents the first part loss model.

[0058] Optionally, the construction process of the second voltage and current curve and the determination of the second part loss model of the heterogeneous hybrid device during the turn-on process based on the second voltage and current curve include:

[0059] Turn-on process (t5 - t6): V GS and V GE are maintained as V Mon and V Ton , and V DS remains the steady-state voltage drop Von of the hybrid device; when the load current I L is less than the turn-on critical current I THWhen the heterogeneous hybrid device is in this state, the MOSFET inside the device conducts all the load current alone; I TH The expression is as follows:

[0060]

[0061] In the formula, V CE (sat) is the IGBT collector saturation voltage, and R DS is the driving resistance of the MOSEFT;

[0062] When the load current is higher than I TH , the forward load current is automatically shunted by the parallel SiC MOSFET and Si IGBT according to R DS and the driving resistance R CE of the IGBT. Define the steady-state currents flowing through the SiC MOSFET and Si IGBT as I Dcond and I Ccond , I Dcond and I Ccond The expressions are as follows:

[0063]

[0064] During the conduction process, the second part loss model of the heterogeneous hybrid device is expressed as:

[0065]

[0066] In the formula, E cond is the second part loss model.

[0067] Optionally, the construction process of the third voltage and current curve and the determination of the third part loss model of the heterogeneous hybrid device during the turn-off process based on the third voltage and current curve include:

[0068] Sixth stage (t6 - t7): The driving signal V dr_mos of the MOSFET and the driving signal V dr_igbt [[ID=�3]]of the IGBT jump from high level to low level respectively, and V GS and V GE gradually decrease; The expressions of V GS and V GE are as follows:

[0069]

[0070] In the formula, V Mon and V Moff are the driving positive voltage and driving negative voltage of the SiC MOSFET respectively, and V Ton and V Toffare the positive drive voltage and negative drive voltage of the Si IGBT, τ M and τ T are the charging constants of the SiC MOSFET and the Si IGBT respectively, where τ M = R gm C iss , τ T = R gt C ies ; R gm is the gate resistance of the SiC MOSFET, and R gt is the gate resistance of the Si IGBT;

[0071] At time t7, the MOSFET and the IGBT enter the amplification region from the variable resistance region, and I D , I C remain unchanged, and V GS and V GE remain at the Miller plateau V GPM2 and V GPT2 unchanged. The expressions for V GPM2 and V GPT2 are as follows:

[0072] V GPM2 = aR gm C gd + V Moff

[0073] V GPT2 = aR gt C gc + V Toff

[0074]

[0075] In the formula, C gd is the gate-drain capacitance of the SiC MOSFET, C gc is the gate-collector capacitance of the Si IGBT, a is the gate-source voltage correction factor of the SiC MOSFET, I L is the load current, V THM is the gate threshold voltage of the MOSFET, V THT is the gate threshold voltage of the IGBT, g fs is the transconductance of the MOSFET, and g fe is the transconductance of the IGBT;

[0076] From the shunt characteristics, the peak current I Dpoff during the turn-off process of the MOSFET and the peak current I Cpoff during the turn-off process of the IGBT are:

[0077]

[0078] Wherein, V CE (sat) is the IGBT collector saturation voltage;

[0079] The expression of the duration of the sixth stage and the expression of the first turn-off loss of the heterogeneous hybrid device are as follows:

[0080]

[0081] E off (t6,t7) = V on I L (t7 - t6)

[0082] Wherein, V on is the on-state voltage drop of the heterogeneous hybrid device, and E off (t6,t7) is the first turn-off loss;

[0083] Seventh stage (t7 - t8): After time t7, the MOSFET and IGBT enter the saturation region, and V GE , V GS enter the Miller plateau, and I[[ID=3 three]] D , I C also remain unchanged. At this time, C gc and C gd discharge to the drive circuit, and V DS rises rapidly. The expression of its change rate and the expression of the Miller plateau duration are as follows:

[0084]

[0085] During this stage, the second turn-off loss of the heterogeneous hybrid device is:

[0086]

[0087] Wherein, E off (t8,t7) is the second turn-off loss;

[0088] Eighth stage (t8 - t9): At time t8, as V DS reaches the bus voltage and cannot continue to rise, V GE , V GS begin to decline. Since the MOSFET and IGBT are still operating in the amplification region, I D , I C begin to decline. The expressions of the change rates of I D and I C are as follows:

[0089]

[0090] Wherein, L sis the parasitic inductance of the source line, L e is the parasitic inductance of the emitter line;

[0091] In this stage, the duration and the third turn-off loss of the heterogeneous hybrid device can be approximately expressed as:

[0092]

[0093] In the formula, E off (t8, t9) is the third turn-off loss, V DC is the DC bus voltage;

[0094] The ninth stage 9 (t9 - t 10 ): At time t9, V GS drops to V THM and then the MOSFET is completely turned off. V GE and V GS continue to drop, and I p and I C continue to decrease at the same speed;

[0095] In this stage, the duration of this stage and the fourth turn-off loss of the heterogeneous hybrid device can be approximately expressed as:

[0096]

[0097] In the formula, E off (t9, t 10 ) is the fourth turn-off loss;

[0098] The tenth stage (t 10 - t 11 ): At time t 10 , V GE drops to V THT , the IGBT channel closes, and I C enters the tail current stage. At time t 11 , the IGBT is completely turned off, and V GE and V GS decrease to V Moff and V Toff ;

[0099] The fifth turn-off loss of the heterogeneous hybrid device in this stage can be approximately expressed as:

[0100] E off (t 10 , t 11 ) = E res

[0101] In the formula, E off (t 10 , t 11 ) is the fifth turn-off loss, Eres is the residual loss of the IGBT;

[0102] Based on the first turn-off loss, the second turn-off loss, the third turn-off loss, the fourth turn-off loss, and the fifth turn-off loss, determine the third part loss model of the heterogeneous hybrid device during the turn-off process:

[0103] E off = E off (t6, t7) + E off (t7, t8) + E off (t8, t9) + E off (t9, t 10 ) + E off (t 10 , t 11 )

[0104] In the formula, E off is the third part loss model.

[0105] The present application has the following beneficial effects:

[0106] The method proposed in the present application divides the entire switching transient stage of the heterogeneous hybrid device into 11 stages according to the device state, and details the working principles of the heterogeneous hybrid device in each stage. Combining the physical characteristics of the device, considering the influence of the junction temperature and the parasitic parameters introduced by the device itself and the circuit layout, the transient mathematical expressions of the current flowing through the MOSFET and the IGBT and the voltage drop across the hybrid device in different stages and the duration expressions of each stage are derived, completing the voltage and current curve modeling of the heterogeneous hybrid device. Combining the established voltage and current and duration expressions of each stage, the loss mathematical expressions of the hybrid device in each stage are derived, and by combining voltage, current, and loss, a behavior model for the entire switching transient stage of the heterogeneous hybrid device is established, laying a theoretical foundation for the popularization and application of the hybrid device.

[0107] In addition to the purposes, features, and advantages described above, the present application has other purposes, features, and advantages. The following will refer to the accompanying drawings to make a further detailed description of the present application. Description of the Drawings

[0108] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:

[0109] Figure 1 is a schematic diagram of the double pulse test circuit structure provided by the embodiment of the present application;

[0110] Figure 2It is a schematic flow chart of a modeling method for the switching transient full-stage behavior model of a heterogeneous hybrid device provided by an embodiment of the present application;

[0111] Figure 3 It is a waveform schematic diagram of the turn-on process of a heterogeneous hybrid device provided by an embodiment of the present application;

[0112] Figure 4 It is a waveform schematic diagram of the conduction process of a heterogeneous hybrid device provided by an embodiment of the present application;

[0113] Figure 5 It is a waveform schematic diagram of the turn-off process of a heterogeneous hybrid device provided by an embodiment of the present application. Detailed implementation manners

[0114] The following will describe the embodiments of the present application in detail with reference to the accompanying drawings. However, the present application can be implemented in many different ways defined and covered by the claims.

[0115] To solve the problems raised in the background art, the model constructed in the present application performs full-stage analysis based on a double-pulse test platform. The double-pulse test circuit structure is as Figure 1 shown, where V DC is the DC bus voltage, C bus is the voltage-stabilizing capacitor, L load is the load inductor, L p is the bus parasitic inductor. D1 and D2 are the equivalent body diodes of the MOSFET and IGBT when the upper bridge arm conducts. C1 and C2 are the junction capacitors corresponding to D1 and D2. C gd , C gs , C ds are the gate-drain capacitance, gate-source capacitance, and drain-source capacitance of the SiC MOSFET respectively. C gc , C ge , C ce are the gate-collector capacitance, gate-emitter capacitance, and collector-emitter capacitance of the Si IGBT respectively. L s , L e are the parasitic inductors of the source and emitter lines respectively. V dr_mos and V dr_igbt are the drive signals of the SiC MOSFET and Si IGBT respectively. R gm and R gt are the gate resistors of the two respectively. L gm , L gt correspond to the parasitic inductors of the drive circuits of the two respectively.

[0116] As Figure 2 shown, the present application provides a modeling method for the switching transient full-stage behavior model of a heterogeneous hybrid device, including:

[0117] Step S101: Obtain the first voltage and current curves during the turn-on process of the heterogeneous hybrid device;

[0118] Based on the first voltage and current curves, determine the first part loss model during the turn-on process of the heterogeneous hybrid device;

[0119] During the turn-on process, the turn-on process of the heterogeneous hybrid device can be mainly divided into five stages, as Figure 3 shown, V GS and V GE are the gate-source voltage and the gate-emitter voltage respectively, I C and I D are the currents flowing through the SiC MOSFET and the Si IGBT respectively, and V DS is the drain-source voltage.

[0120] The first stage (t0 - t1): At time t0, the driving voltage starts to charge the input capacitance C ies of the Si IGBT and the input capacitance C iss of the SiC MOSFET (C iss = C gd + C gs , C ies = C ge + C gc , C gd and C gs are the gate-drain capacitance and the gate-source capacitance of the SiC MOSFET respectively, and C gc and C ge are the gate-collector capacitance and the gate-emitter capacitance of the Si IGBT respectively), and the first expression of the gate-source voltage V GS and the second expression of the gate-emitter voltage V GE are as follows:

[0121]

[0122] In the formula, e is the time constant, V Mon and V Moff are the driving positive voltage and the driving negative voltage of the SiC MOSFET respectively, V Ton and V Toff are the driving positive voltage and the driving negative voltage of the Si IGBT respectively. τ M and τ T are the charging constants of the SiC MOSFET and the Si IGBT respectively, where τ M = R gm C iss , τ T = R gt C ies ; R gm is the gate resistance of the SiC MOSFET, Rgt is the gate resistance of the Si IGBT; t represents time;

[0123] In the first stage, V GS and V GE both do not reach the threshold voltage V THM of the MOSFET and the threshold voltage V THT of the IGBT. Therefore, both the MOSFET and the IGBT remain in the off state, and the drain current I D and the collector current I C are always zero, and the drain-source voltage V DS remains at the DC bus voltage V DC . Therefore, the first turn-on loss of the heterogeneous hybrid device in this stage is zero. The duration of this stage is:

[0124]

[0125] Second stage (t1 - t2): At time t1, V GS rises to the gate threshold voltage V THM of the MOSFET, I D gradually rises, V GS and V GE continue to increase. The second expression of V GS and V GE is the same as the first expression. At this time, the MOSFET is in the amplification region. According to the characteristics of the power device amplification region, the first I D expression is as follows:

[0126] I D (t) = g fs (V GS (t) - V THM ) (4)

[0127] where g fs is the transconductance of the MOSFET;

[0128] In the second stage, the IGBT is not conducting, I C remains zero, and the current I p flowing through the hybrid device changes rapidly, acting on the circuit stray inductance causes V DS to decrease slightly but still close to V DC ; According to the first expression of V GS and V GE , the initial time difference when I D , I C starts to rise is:

[0129]

[0130] During the second stage, the loss E of the MOSFET on_MOS , the loss E of the IGBT on_IGBT and the second turn-on loss E of the heterogeneous hybrid device on (t1,t2) can be approximated as:

[0131]

[0132] E on_IGBT (t1,t2) = 0 (7)

[0133] E on (t1,t2) = E on_MOS (t1,t2) (8)

[0134] Third stage (t2 - t3): At time t2, V GE rises to the IGBT gate threshold voltage V THT , I C gradually rises, V GS and V GE continue to increase. The first I C expression is as follows:

[0135] I C (t) = g fe (V GE (t) - V THT ) (9)

[0136] Where g fe is the transconductance of the IGBT;

[0137] During the third stage, the change rate of the first I D , the change rate of the first I C can be expressed as:

[0138]

[0139] At time t3, all the load current transfers to the hybrid device branch, and due to the existence of the junction capacitances of D1 and D2, there is a current overshoot phenomenon, and I P continues to increase to its peak value I peak , I peak The expression is:

[0140]

[0141] Where Q rr1 is the reverse recovery charge of the MOSFET, and Q rr2 is the reverse recovery charge of the IGBT;

[0142] From Figure 3 it can be seen that the following relationship exists between the current peak value and time:

[0143]

[0144] Based on the first I D change rate, the first I C change rate, the I peak expression and the expression of the current peak value and time, that is, according to formulas (10)-(13), determine the current peak value I of the MOSFET during the turn-on process Dpon , the current peak value I of the IGBT during the turn-on process Cpon , and the expression is as follows:

[0145]

[0146]

[0147] During the third stage, the loss E of the MOSFET on_MOS (t2, t3), the loss E of the IGBT on_IGBT (t2, t3) and the third turn-on loss E of the heterogeneous hybrid device on (t2, t3) can be approximated as:

[0148]

[0149] E on (t2, t3) = E on_MOS (t2, t3) + E on_IGBT (t2, t3) (18)

[0150] Fourth stage (t3 - t4): I P reaches the peak I peak , and then gradually recovers to the load current I L , V GS and V GE enter the Miller plateau and remain at the plateau voltage V GPM1 and V GPT1 unchanged. The drive circuit only charges C gd and C ge , which in turn causes V DS to drop significantly. The change rate of V DS can be expressed as:

[0151]

[0152] V DS The time required for the drop is as follows:

[0153]

[0154] In the formula, V on is the on-state voltage drop of the heterogeneous hybrid device;

[0155] During the fourth stage, the fourth turn-on loss E on (t3, t4) of the heterogeneous hybrid device can be approximately expressed as:

[0156]

[0157] Stage 5 (t4 - t5): The Miller plateau ends, and V GS and V GE continue to rise. At this time, both the IGBT and the MOSFET are in the variable resistance region, and the commutation process is completed according to the magnitude of the on-resistance of the two, reaching a steady state at time t5; at this time, the fifth turn-on loss E on (t4, t5) of the heterogeneous hybrid device can be approximately expressed as:

[0158] E on (t4, t5) = V on I L (t5 - t4) (22)

[0159] Based on the first turn-on loss, the second turn-on loss, the third turn-on loss, the fourth turn-on loss, and the fifth turn-on loss, the first overall loss model of the heterogeneous hybrid device during the turn-on process is determined as follows:

[0160] E on = E on (t1, t2) + E on (t2, t3) + E on (t3, t4) + E on (t4, t5) (23)

[0161] Step S102: Obtain the second voltage and current curves of the heterogeneous hybrid device during the conduction process;

[0162] Based on the second voltage and current curves, determine the second partial loss model of the heterogeneous hybrid device during the conduction process;

[0163] After the heterogeneous hybrid device is turned on, it will enter the conduction process. Next, as Figure 4 shown, the conduction process will be described in detail:

[0164] V GS and V GE are maintained at V Mon and V Ton , and V DS is kept as the steady-state voltage drop Von of the hybrid device. When the load current I L is less than the turn-on critical current I THWhen the load current is lower than a certain value, the MOSFET inside the heterogeneous hybrid device conducts all the load current alone. I TH The expression is as follows:

[0165]

[0166] In the formula, V CE (sat) is the IGBT collector saturation voltage, and R DS is the driving resistance of the MOSEFT;

[0167] When the load current is higher than I TH , the forward load current is automatically shunted by the parallel SiC MOSFET and Si IGBT according to R DS and the driving resistance R CE of the IGBT. The steady-state currents flowing through the SiC MOSFET and Si IGBT are defined as I Dcond and I Ccond , and the expressions of I Dcond and I Ccond are as follows:

[0168]

[0169] Among them, R DS and R CE are negatively correlated with their own driving voltages and linearly positively correlated with their own junction temperatures, specifically as follows:

[0170]

[0171] Among them, T j_MOS , K R_MOS , V GS_ref (25°C), V GS , R DS_ref (25°C) and a are the junction temperature, on-resistance temperature influence factor, reference gate-source voltage, gate-source voltage, reference on-resistance, and gate-source voltage correction factor of the SiC MOSFET respectively, and T j_IGBT , K R_IGBT , V GE_ref (25°C), V GE , R CE_ref (25°C) and b are the junction temperature, on-resistance temperature influence factor, reference gate-emitter voltage, gate-emitter voltage, reference on-resistance, and gate-emitter voltage correction factor of the IGBT respectively. When the device conducts, the gate-source voltage and gate-emitter voltage are the driving positive voltages of the two.

[0172] Combining equations (25) and (26), the second part of the loss model of the heterogeneous hybrid device can be expressed as:

[0173]

[0174] In the formula, E cond is the second part loss model.

[0175] Step S103: Obtain the third voltage and current curves of the heterogeneous hybrid device during the turn-off process;

[0176] Based on the third voltage and current curves, determine the third part loss model of the heterogeneous hybrid device during the turn-off process;

[0177] After the conduction of the heterogeneous hybrid device ends, it will enter the turn-off process. The turn-off process is mainly divided into 5 stages. The turn-off waveform comparison diagrams of the heterogeneous hybrid device under different driving negative voltage combinations are as Figure 5 shown:

[0178] Sixth stage (t6 - t7): The driving signal V dr_mos of the MOSFET and the driving signal V dr_igbt of the IGBT respectively jump from high level to low level, and V GS and V GE gradually decrease; The expressions of V GS and V GE are as follows:

[0179]

[0180] The switching speed of the MOSFET is faster than that of the IGBT, and V GS drops significantly in a short time. The drop of V GS causes an increase in the on-resistance of the MOSFET, resulting in a change in the current sharing between the MOSFET and the IGBT. At this time, the increase in the on-resistance will also cause a slight increase in V DS .

[0181] At time t7, the MOSFET and the IGBT enter the amplification region from the variable resistance region, and I D , I C remain unchanged, and V GS and V GE remain at the Miller plateau V GPM2 and V GPT2 unchanged. The expressions of V GPM2 and V GPT2 are as follows:

[0182]

[0183] At time t7, the on-resistances R DS and R CE of the MOSFET and the IGBT satisfy equations (27) and (28). From the current sharing characteristics, the peak current I Dpoff during the turn-off process of the MOSFET and the peak current ICpoff is:

[0184]

[0185] The expression for the duration of the sixth stage and the expression for the first turn-off loss of the heterogeneous hybrid device are as follows:

[0186]

[0187] Seventh stage (t7 - t8): After time t7, the MOSFET and IGBT enter the saturation region, V GE , V GS enter the Miller plateau, and I D , I C also remains unchanged. At this time, C gc and C gd discharge to the drive circuit, and V DS rises rapidly. The expression for its rate of change and the expression for the duration of the Miller plateau are as follows:

[0188]

[0189] During this stage, the second turn-off loss of the heterogeneous hybrid device is:

[0190]

[0191] In the formula, E off (t7, t8) is the second turn-off loss;

[0192] Eighth stage (t8 - t9): At time t8, as V DS reaches the bus voltage and cannot continue to rise, V GE , V GS begin to decline. Since the MOSFET and IGBT are still operating in the amplification region, I D , I C begin to decline. The changing current acts on L p to generate a voltage drop in the same direction as the DC bus voltage, and V DS continues to rise above V DC . The load current transfers to the D1 circuit during this stage. The expressions for the rates of change of I D and I C are as follows:

[0193]

[0194] During this stage, the duration and the third turn-off loss of the heterogeneous hybrid device can be approximately expressed as:

[0195]

[0196] where, E off (t8, t9) is the third turn-off loss;

[0197] The ninth stage 9 (t9 - t 10 ): At time t9, V GS drops to V THM and then the MOSFET is completely turned off. V GE and V GS continue to drop, and I p and I C continue to decrease at the same speed;

[0198] During this stage, the duration of this stage and the fourth turn-off loss of the heterogeneous hybrid device can be approximately expressed as:

[0199]

[0200]

[0201] where, E off (t9, t 10 ) is the fourth turn-off loss;

[0202] The tenth stage (t 10 - t 11 ): At time t 10 , V GE drops to V THT , and the IGBT channel closes. I C enters the tail current stage, and at time t 11 , the IGBT is completely turned off, and V GE and V GS drop to V Moff and V Toff ;

[0203] The fifth turn-off loss of the heterogeneous hybrid device in this stage can be approximately expressed as:

[0204] E off (t 10 , t 11 ) = E res (48)

[0205] Based on the first turn-off loss, the second turn-off loss, the third turn-off loss, the fourth turn-off loss, and the fifth turn-off loss, determine the second overall loss model of the heterogeneous hybrid device during the turn-off process:

[0206] E off = E off (t6, t7) + E off (t7, t8) + E off (t8, t9) + E off(t9,t 10 )+E off (t 10 ,t 11 ) (49)

[0207] Step S104: Based on the first voltage-current curve, the second voltage-current curve, and the third voltage-current curve, construct a transient model of the voltage-current curve of the heterogeneous hybrid device;

[0208] Based on the first partial loss model, the second partial loss model, and the third partial loss model, construct a complete loss model of the heterogeneous hybrid device;

[0209] Combine the first voltage-current curve during the turn-on process, the second voltage-current curve during the conduction process, and the third voltage-current curve during the turn-off process, and a transient model of the voltage-current curve of the heterogeneous hybrid device is constructed.

[0210] Adding the first partial loss model, the second partial loss model, and the third partial loss model together can form a complete loss model of the heterogeneous hybrid device as follows:

[0211] E 完整 =E on +E cond +E off (50)

[0212] where E 完整 is the complete loss model.

[0213] Step S105: Based on the transient model of the voltage-current curve of the heterogeneous hybrid device and the complete loss model of the heterogeneous hybrid device, determine the switching transient full-stage behavior model of the heterogeneous hybrid device.

[0214] By combining the transient model of the voltage-current curve and the complete loss model, the switching transient full-stage behavior model of the heterogeneous hybrid device can be formed.

[0215] Combining the models of the turn-on, conduction, and turn-off processes can predict the voltage-current curve and overall loss of the heterogeneous hybrid device. This model can be applied to the calculation of the switching loss of the voltage-current curve under high voltage and high frequency. In addition, this model can also be used to predict the switching waveform of the heterogeneous hybrid device.

[0216] In summary, for the method proposed in this application, the entire switching transient stage of the heterogeneous hybrid device is divided into 11 stages according to the device state, and the working principles of the heterogeneous hybrid device in each stage are analyzed in detail. Combining the physical characteristics of the device, considering the influence of the junction temperature and the parasitic parameters introduced by the device itself and the circuit layout, the transient mathematical expressions of the current flowing through the MOSFET and the IGBT in different stages and the voltage drop across the hybrid device, as well as the expressions for the duration of each stage, are derived. The voltage and current curve modeling of the heterogeneous hybrid device is completed. Combining the established voltage and current expressions with the expressions for the duration of each stage, the loss mathematical expressions of the hybrid device in each stage are derived. By combining voltage, current, and loss, a behavior model for the entire switching transient stage of the heterogeneous hybrid device is established, laying a theoretical foundation for the popularization and application of the hybrid device.

[0217] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A modeling method for the switching transient full-stage behavior model of a heterogeneous hybrid device, characterized in that, Including: Obtain the first voltage and current curves of the heterogeneous hybrid device during the turn-on process; Based on the first voltage and current curves, determine the first partial loss model of the heterogeneous hybrid device during the turn-on process; Obtain the second voltage and current curves of the heterogeneous hybrid device during the conduction process; Based on the second voltage and current curves, determine the second partial loss model of the heterogeneous hybrid device during the conduction process; Obtain the third voltage and current curves of the heterogeneous hybrid device during the turn-off process; Based on the second voltage and current curves, determine the third partial loss model of the heterogeneous hybrid device during the turn-off process; Based on the first voltage and current curves, the second voltage and current curves, and the third voltage and current curves, construct a transient model of the voltage and current curves of the heterogeneous hybrid device; Based on the first partial loss model, the second partial loss model, and the third partial loss model, construct a complete loss model of the heterogeneous hybrid device; Based on the transient model of the voltage and current curves of the heterogeneous hybrid device and the complete loss model of the heterogeneous hybrid device, determine the switching transient full-stage behavior model of the heterogeneous hybrid device.

2. The method according to claim 1, wherein The construction process of the first voltage and current curves and determining the first partial loss model of the heterogeneous hybrid device during the turn-on process based on the first voltage and current curves Including: The first stage (t0 - t1): At time t0, start driving the voltage to charge the input capacitance C of the Si IGBT ies and the input capacitance C of the SiC MOSFET iss (C iss = C gd + C gs , C ies = C ge + C gc , C gd , C gs are the gate-drain capacitance and the gate-source capacitance of the SiC MOSFET respectively, and C gc , C ge are the gate-collector capacitance and the gate-emitter capacitance of the Si IGBT respectively), the first expression of the gate-source voltage V GS and the second expression of the gate-emitter voltage V GE are as follows: where e is the time constant, V Mon and V Moff are the positive driving voltage and negative driving voltage of the SiC MOSFET, respectively, and V Ton and V Toff are the positive driving voltage and negative driving voltage of the Si IGBT, respectively. τ M and τ T are the charging constants of the SiC MOSFET and the Si IGBT, respectively, where τ M = R gm C iss , τ T = R gt C ies ; R gm is the gate resistance of the SiC MOSFET, and R gt is the gate resistance of the Si IGBT; t represents time; In the first stage, V GS and V GE both do not reach the threshold voltage V of the MOSFET THM and the threshold voltage V of the IGBT THT . Currently, both the current MOSFET and the current IGBT are maintained in the off state, and the drain current I D and the collector current I C are always zero, and the drain-source voltage V DS remains at the DC bus voltage V DC . The first turn-on loss of the heterogeneous hybrid type in this stage is zero, and the duration of this stage is: Second stage (t1 - t2): At time t1, V GS rises to the MOSFET gate threshold voltage V THM , I D gradually rises, V GS and V GE continue to increase. The expression of V GS is the first expression, and the expression of V GE is the second expression. The MOSFET is in the amplification region at this time. According to the characteristics of the amplification region of the power device, the first I D expression is as follows: I D g(t)=g fs (V GS (t) - V THM ) where g fs is the transconductance of the MOSFET; During the second stage, the IGBT is not conducting, and I C remains zero. The current I p flowing through the hybrid device changes rapidly, acting on the circuit stray inductance to cause V DS to decrease slightly but still remain close to V DC ; According to the first expression of V GS and V GE , the initial time difference at which I D and I C begin to rise is: During the second stage, the loss E of the MOSFET on_MOS , the loss E of the IGBT on_IGBT and the second turn-on loss E of the heterogeneous hybrid device on (t1, t2) can be approximated as: E on_IGBT (t1, t2) = 0 E on (t1, t2) = E on_MOS (t1, t2) Third stage (t2 - t3): At time t2, V GE rises to the IGBT gate threshold voltage V THT , I C gradually rises, V GS and V GE continue to increase, the first I C The expression is as follows: I C g(t) = g fe (V GE (t) - V THT ) where g fe is the transconductance of the IGBT; In the third stage, the first I in this stage D change rate, the first I C The change rate can be expressed as: Wherein, L s is the parasitic inductance of the source line, and L e is the parasitic inductance of the emitter line; At time t3, all load currents are transferred to the hybrid device branch, and I P continuously increases to its peak value I peak , I peak The expression is: Wherein, Q rr1 is the reverse recovery charge of the MOSFET, and Q rr2 is the reverse recovery charge of the IGBT; The expression of the current peak value and time is: Based on the first I D change rate, the first I C change rate, the I peak expression, and the expression of the current peak value and time, determine the current peak value I of the MOSFET during the turn-on process Dpon , the current peak value I of the IGBT during the turn-on process Cpon , and the expression is as follows: During the third stage, the loss E of the MOSFET on_MOS (t2, t3), the loss E of the IGBT on_IGBT (t2, t3), and the third turn-on loss E of the heterogeneous hybrid device on (t2, t3) can be approximated as: E on (t2, t3) = E on_MOS (t2, t3) + E on_IGBT (t2, t3) Fourth stage (t3 - t4): I P Reaches peak I peak , and then gradually returns to load current I L , V GS and V GE enter the Miller plateau and remain at the plateau voltage V GPM1 and V GPT1 unchanged. The drive circuit only charges C gd and C ge , which in turn causes V DS to drop significantly. The rate of change of V DS can be expressed as: V DS The expression for the time required for descent is as follows: where V on is the on-voltage drop of the heterojunction hybrid device; During the fourth stage, the fourth turn-on loss E on (t3, t4) of the heterogeneous hybrid device can be approximately expressed as: The fifth stage (t4 - t5): The Miller platform ends, and V GS and V GE continue to rise. At this time, both the IGBT and the MOSFET are in the variable resistance region, and the two complete the commutation process according to the magnitude of the on-resistance, reaching a steady state at the moment t5. At this time, the fifth turn-on loss E on (t4, t5) can be approximately expressed as: E on (t4, t5) = V on I L (t5 - t4) Based on the first turn-on loss, the second turn-on loss, the third turn-on loss, the fourth turn-on loss, and the fifth turn-on loss, determine the first overall loss model of the heterogeneous hybrid device during the turn-on process as follows: E on = E on (t1, t2) + E on (t2, t3) + E on (t3, t4) + E on (t4, t5) where E on represents the first part loss model.

3. The method according to claim 1, wherein The construction process of the second voltage and current curves and determining the second partial loss model of the heterogeneous hybrid device during the conduction process based on the second voltage and current curves Including: Conduction process (t5 - t6): V GS With V GE Maintained at V Mon With V Ton , V DS Kept as the steady - state voltage drop Von of the hybrid device; when the load current I L is less than the turn - on critical current I of the IGBT TH , the MOSFET inside the heterogeneous hybrid device conducts all the load current alone; I TH The expression is as follows: Wherein, V CE (sat) is the IGBT collector saturation voltage, and R DS is the driving resistance of the MOSEFT; When the load current is higher than I TH the forward load current is automatically shunted by the parallel SiC MOSFET and Si IGBT according to R DS and the drive resistances R CE of the IGBT. Define the steady-state currents flowing through the SiC MOSFET and Si IGBT as I Dcond and I Ccond I Dcond and I Ccond The expressions are as follows: During the conduction process, the second partial loss model of the heterogeneous hybrid device is expressed as: where E cond is the second part loss model.

4. The method according to claim 1, characterized in that, The construction process of the third voltage and current curves and determining the third partial loss model of the heterogeneous hybrid device during the turn-off process based on the third voltage and current curves Including: Sixth stage (t6 - t7): The drive signal V of the MOSFET dr_mos and the drive signal V of the IGBT dr_igbt respectively jump from high level to low level, V GS and V GE gradually decrease; V GS and V GE are expressed as follows: Wherein, V Mon and V Moff are respectively the positive driving voltage and negative driving voltage of the SiC MOSFET, V Ton and V Toff are respectively the positive driving voltage and negative driving voltage of the Si IGBT, τ M and τ T are respectively the charging constants of the SiC MOSFET and the Si IGBT, where τ M = R gm C iss , τ T = R gt C ies ; R gm is the gate resistance of the SiC MOSFET, R gt is the gate resistance of the Si IGBT; At time t7, the MOSFET and IGBT enter the amplification region from the variable resistance region, and I D , I C remains unchanged, and V GS and V GE remain at the Miller plateau V GPM2 and V GPT2 unchanged, and the expressions for V GPM2 and V GPT2 are as follows: V GPM2 = aR gm C gd + V Moff V GPT2 = aR gt C gc + V Toff Wherein, C gd is the gate-drain capacitance of the SiC MOSFET, C gc is the gate-collector capacitance of the Si IGBT, a is the gate-source voltage correction factor of the SiC MOSFET, I L is the load current, V THM is the gate threshold voltage of the MOSFET, V THT is the gate threshold voltage of the IGBT, g fs is the transconductance of the MOSFET, g fe is the transconductance of the IGBT; From the shunt characteristics, the peak current I during the MOSFET turn-off process Dpoff and the peak current I during the IGBT turn-off process Cpoff are as follows: where V CE (sat) is the IGBT collector saturation voltage; The expression of the duration of the sixth stage and the first turn-off loss of the heterogeneous hybrid device is as follows: Wherein, V on is the on-state voltage drop of the heterogeneous hybrid device, and E off (t6, t7) is the first turn-off loss; The seventh stage (t7 - t8): After the moment of t7, the MOSFET and the IGBT enter the saturation region, and V GE , V GS enter the Miller plateau, and I D , I C also remain unchanged. At this time, C gc and C gd discharge to the drive circuit, and V DS rises rapidly. The expressions for its rate of change and the duration of the Miller plateau are as follows: Within this stage, the second turn-off loss of the heterogeneous hybrid device is: where, E off (t8, t7) is the second turn-off loss; The eighth stage (t8 - t9): At time t8, as V DS reaches the bus voltage and cannot continue to rise, V GE , V GS starts to decline. Since the MOSFET and IGBT are still operating in the amplification region, I D , I C begin to decline. The expressions for the change rates of I D and I C are as follows: where L s is the parasitic inductance of the source line, and L e is the parasitic inductance of the emitter line; Within this stage, the duration and the third turn-off loss of the heterogeneous hybrid device can be approximately expressed as: Where, E off (t8, t9) is the third turn-off loss, V DC is the DC bus voltage; Ninth stage 9 (t9 - t 10 ): At time t9, V GS drops to V THM and then the MOSFET is completely turned off. V GE and V GS continue to drop, and I p and I C continue to decrease at the same rate; Within this stage, the duration of this stage and the fourth turn-off loss of the heterogeneous hybrid device can be approximately expressed as: where E off (t9, t 10 ) is the fourth turn-off loss; The tenth stage (t 10 -t 11 ): At time t 10 when V GE drops to V THT , the IGBT channel closes and I C enters the tail current stage. At time t 11 the IGBT is fully turned off, and V GE and V GS drop to V Moff and V Toff ; The fifth turn-off loss of the heterogeneous hybrid device in this stage can be approximately expressed as: E off (t 10 ,t 11 ) = E res where E off (t 10 , t 11 ) is the fifth turn-off loss, E res is the IGBT residual loss; Based on the first turn-off loss, the second turn-off loss, the third turn-off loss, the fourth turn-off loss, and the fifth turn-off loss, determine the third partial loss model of the heterogeneous hybrid device during the turn-off process: E off = E off (t6, t7) + E off (t7, t8) + E off (t8, t9) + E off (t9, t 10 ) + E off (t 10 , t 11 ) where E off is the third part loss model.

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