Method for estimating losses of hybrid switching converter based on simulation model

Abstract

The application discloses a method for estimating loss of a hybrid switching converter based on a simulation model, and is implemented according to the following steps: selecting SiC-MOSFET and Si-IGBT device models according to system capacity; performing parameter calibration on SiC-MOSFET double-pulse testing and Si-IGBT pulse testing according to the device models; turning off SiC / SiHyS converter SiC-MOSFET and Si-IGBT, testing the hybrid switching tube voltage drop V F when the load current flows reversely; estimating the loss of the SiC / SiHyS converter based on a Matlab simulation model; calculating the junction temperature of the device according to the loss, and updating the SiC-MOSFET value and the Si-IGBT value in real time to obtain an accurate loss estimation value, and completing the estimation. The method solves the problems that the existing loss estimation method for the hybrid switching power is inaccurate, and the system loss cannot be calculated in real time in the entire power range.

Description

Technical Field

[0001] This invention belongs to the technical field of power electronic equipment development methods, specifically relating to a method for estimating the losses of hybrid switching converters based on simulation models. Background Technology

[0002] Power loss estimation is one of the core steps in the early development of power electronic equipment. Its accuracy directly affects the execution of the overall system plan, especially the estimation and design of system power density and heat dissipation modules.

[0003] Meanwhile, due to the significant advantages of hybrid switches (SiC / SiHyS) combining silicon carbide-metal oxide semiconductor field-effect transistors (SiC-MOSFETs) and silicon-insulated gate bipolar transistors (Si-IGBTs) in terms of system cost and conduction losses, industry and academia have conducted extensive research on this type of hybrid switch. Especially regarding the power loss of hybrid switches under different triggering modes, numerous studies have constructed loss models based on the static and dynamic characteristics of the devices and achieved high-precision loss estimation through parameter optimization. However, the methods used all linearize the switching and conduction processes of the devices and then construct loss models in time-segmented manner.

[0004] The main problems with this method are: First, the time-segmented linear modeling process does not conform to the actual nonlinear switching process of the device, and it ignores the commutation power loss of SiC-MOSFET and Si-IGBT during the turn-on and turn-off commutation process, resulting in inaccurate estimation results. Second, the power loss model constructed in time segments is applicable to specific system operating conditions, but because the triggering modes of SiC / Si hybrid switches are diverse, the loss model needs to correspond one-to-one with the triggering mode. When the system operating conditions and the triggering mode of SiC / Si HyS change, the loss model needs to be adjusted or switched before the power loss can be estimated. For a complex cascaded converter system, the system loss cannot be calculated in real time across the entire power range.

[0005] Therefore, the current time-sharing modeling loss estimation method does not meet the requirements of SiC / SiHyS power loss characteristic analysis. New loss estimation methods are needed for new hybrid parallel switching structures to promote the application of SiC / SiHyS in the market. Summary of the Invention

[0006] The purpose of this invention is to provide a method for estimating the losses of hybrid switching converters based on simulation models, which solves the problems of inaccurate estimation results and the inability to calculate system losses in real time across the entire power range in current methods for estimating power losses of hybrid switching converters.

[0007] The technical solution of this invention is a method for estimating the losses of a hybrid switching converter based on a simulation model, specifically implemented according to the following steps:

[0008] Step 1: Select the SiC-MOSFET and Si-IGBT device models according to the system capacity;

[0009] Step 2: Perform parameter calibration for SiC-MOSFET dual-pulse test and Si-IGBT pulse test according to the device model;

[0010] Step 3: Turn off the SiC-MOSFET and Si-IGBT in the SiC / SiHyS converter, and test the voltage drop V of the hybrid switch when the load current flows in reverse. F ;

[0011] Step 4: Estimate the loss of the SiC / SiHyS converter based on the Matlab simulation model;

[0012] Step 5: Calculate the junction temperature of the device based on the losses and update the SiC-MOSFET in real time. Values ​​and Si-IGBTs The value is used to obtain an accurate estimate of the loss, thus completing the estimation.

[0013] The present invention is further characterized in that: in step 2, the parameter calibration of the SiC-MOSFET double-pulse test is performed in the following specific steps:

[0014] Loss functions of SiC-MOSFET turn-on and turn-off based on data curve fitting and The function coefficients are calibrated using the results of a commonly used double-pulse test.

[0015]

[0016]

[0017] Among them, V DC for and The corresponding DC bus voltage in the test conditions, V ds i is the drain-source voltage of the SiC-MOSFET. ds V is the drain-source on-state current of the SiC-MOSFET. DC_testThe DC bus voltage applied during the double-pulse test experiment;

[0018] Based on data curve fitting, the function of SiC-MOSFET on-resistance versus junction temperature is expressed as follows: The parameters of the fitted function were calibrated through high and low temperature experiments.

[0019]

[0020] Among them, T j This is the junction temperature of the device.

[0021] In step 2, the specific steps for parameter calibration using the Si-IGBT pulse test are as follows:

[0022] Based on data curve fitting, the loss function of Si-IGBT turn-on and turn-off and The function coefficients are calibrated using commonly used pulse test results;

[0023]

[0024]

[0025] Based on data curve fitting, the function of Si-IGBT on-resistance and device junction temperature is expressed as follows: The parameters of the fitted function were calibrated through high and low temperature experiments.

[0026]

[0027] Among them, T j This is the junction temperature of the device.

[0028] Step 4 is detailed below:

[0029] Step 4.1: Build a Matlab simulation model of the SiC / Si HyS converter and set up a module for detecting the hybrid switching voltage and device on-current.

[0030] Step 4.2: The collected mixed switch terminal voltage is used to obtain the rising and falling edges of the current through a voltage comparator. The current corresponding to the rising edge of the voltage is recorded as the device turn-off current, and the current corresponding to the falling edge of the voltage is recorded as the device turn-on current.

[0031] Step 4.3: Substitute the current value recorded as the turn-on value into equations (1) and (4), and multiply it by the single sampling time to calculate the turn-on energy loss of SiC-MOSFET and Si-IGBT at a certain moment. By continuously summing this value and dividing it by the total sampling time in real time, the turn-on loss of SiC-MOSFET and Si-IGBT can be obtained.

[0032] Step 4.4: Substitute the current value recorded as the turn-off value into equations (2) and (5), and multiply it by the single sampling period to calculate the turn-off energy loss of SiC-MOSFET and Si-IGBT at a certain moment. By continuously summing this value and dividing it by the total sampling time in real time, the turn-on loss of SiC-MOSFET and Si-IGBT can be obtained.

[0033] Step 4.5: Directly compare the square of the collected SiC-MOSFET on-current value with the on-resistance. Multiply by the sum of the two values ​​and then multiply by the sum of the two values ​​in a single sampling period to obtain the on-state energy loss of the SiC-MOSFET. By continuously summing this value and dividing it by the total sampling time in real time, the on-state energy loss of the SiC-MOSFET can be obtained.

[0034] Step 4.6: Compare the collected Si-IGBT on-state current value with the Si-IGBT on-state saturation voltage drop. Multiply by the sum of the two values ​​and then multiply by the sum of the two values ​​in a single sampling period to obtain the conduction energy loss of the Si-IGBT. By continuously summing this value and dividing it by the total sampling time in real time, the conduction loss of the Si-IGBT can be obtained.

[0035] Step 4.7: Combine the current value recorded as the off with the reverse conduction voltage drop V of the hybrid switch. F Multiply by the dead conduction time to calculate the energy loss during each reverse conduction. and By continuously summing this value and dividing it by the total acquisition time in real time, the dead zone loss of SiC / SiHyS can be obtained.

[0036] Step 4.8: Multiply the five loss values ​​obtained in steps 4.3-4.7 by the corresponding number of switches N to obtain the power loss of SiC-MOSFET and Si-IGBT respectively. Then add the five values ​​after multiplying by N to obtain the total power loss of the SiC / SiHyS converter device.

[0037] In step 5, the on-resistance of the SiC-MOSFET and the saturation on-state voltage drop of the Si-IGBT are estimated using the system thermal resistance and the power loss calculated in step 4, respectively, and updated in real time. and The value of .

[0038] The beneficial effects of this invention are as follows: The simulation-based method for estimating the losses of hybrid switching converters can calculate the energy loss at any given moment during system functional simulation of SiC / SiHyS applications, based on the device terminal voltage and current parameters. Furthermore, it calculates the system power loss in real time throughout the simulation process. Since the voltage and current parameters of SiC-MOSFETs and Si-IGBTs change in real time according to the system's operating state without linearizing the switching and conduction processes of the devices, the switching and conduction losses of each device at any given moment are closer to the actual values, resulting in a more accurate estimation of the system losses. Simultaneously, the loss estimation method proposed in this invention is applicable to any starting mode of SiC / SiHyS, exhibiting strong versatility and significant practical value. Attached Figure Description

[0039] Figure 1 This is a flowchart of the method for estimating the losses of a hybrid switching converter based on a simulation model, as described in this invention.

[0040] Figure 2 This is a flowchart illustrating the key functional fitting and parameter calibration process for SiC-MOSFET and Si-IGBT in the estimation method of this invention.

[0041] Figure 3 This is a schematic diagram of the power loss estimation method for SiC / SiHyS systems based on a Matlab simulation model in the estimation method of this invention. Detailed Implementation

[0042] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0043] Example 1

[0044] This invention provides a method for estimating the losses of hybrid switching converters based on simulation models, such as... Figure 1 As shown, please follow these steps:

[0045] Step 1: Select the SiC-MOSFET and Si-IGBT device models according to the system capacity, and download the corresponding device datasheets from the official website;

[0046] Step 2: Perform parameter calibration for SiC-MOSFET double-pulse test and Si-IGBT pulse test according to the device model in the device datasheet;

[0047] like Figure 2 As shown, the specific steps for parameter calibration in step 2, the SiC-MOSFET double-pulse test, are as follows:

[0048] The loss functions for SiC-MOSFET turn-on and turn-off were fitted based on data curves from the device datasheet. and The function coefficients are calibrated using the results of a commonly used double-pulse test.

[0049]

[0050]

[0051] Among them, V DC for and The corresponding DC bus voltage in the test conditions, V ds i is the drain-source voltage of the SiC-MOSFET. ds V is the drain-source on-state current of the SiC-MOSFET. DC_test The DC bus voltage applied during the double-pulse test experiment;

[0052] Based on curve fitting of data curves from the device datasheet, the function expression of SiC-MOSFET on-resistance versus device junction temperature is used. The parameters of the fitted function were calibrated through high and low temperature experiments.

[0053]

[0054] Among them, T j This is the junction temperature of the device.

[0055] In step 2, the specific steps for parameter calibration using the Si-IGBT pulse test are as follows:

[0056] Based on curve fitting from the device datasheet, the loss functions for Si-IGBT turn-on and turn-off are... and The function coefficients are calibrated using commonly used pulse test results;

[0057]

[0058]

[0059] Based on curve fitting of data from the device datasheet, the function of Si-IGBT on-resistance versus junction temperature is expressed. The parameters of the fitted function were calibrated through high and low temperature experiments.

[0060]

[0061] Among them, T j This is the junction temperature of the device.

[0062] When the SiC-MOSFET and Si-IGBT in the SiC / Si HyS are turned off, the voltage drop V of the hybrid switch is tested when the load current flows in reverse.F This lays the foundation for dead zone losses.

[0063] The above functions and values ​​are saved to lay the foundation for the next step of real-time loss estimation of SiC / Si HyS converters.

[0064] Step 3: Turn off the SiC-MOSFET and Si-IGBT in the SiC / SiHyS converter, and test the voltage drop V of the hybrid switch when the load current flows in reverse. F ;

[0065] Step 4: Estimate the loss of the SiC / SiHyS converter based on the Matlab simulation model;

[0066] like Figure 3 As shown, the specific steps of step 4 are as follows:

[0067] Step 4.1: Build a Matlab simulation model of the SiC / Si HyS converter and set up a module for detecting the hybrid switching voltage and device on-current.

[0068] Step 4.2: The collected mixed switch terminal voltage is used to obtain the rising and falling edges of the current through a voltage comparator. The current corresponding to the rising edge of the voltage is recorded as the device turn-off current, and the current corresponding to the falling edge of the voltage is recorded as the device turn-on current.

[0069] Step 4.3: Substitute the current value recorded as the turn-on value into equations (1) and (4), and multiply it by the single sampling time to calculate the turn-on energy loss of SiC-MOSFET and Si-IGBT at a certain moment. By continuously summing this value and dividing it by the total sampling time in real time, the turn-on loss of SiC-MOSFET and Si-IGBT can be obtained.

[0070] Step 4.4: Substitute the current value recorded as the turn-off value into equations (2) and (5), and multiply it by the single sampling period to calculate the turn-off energy loss of SiC-MOSFET and Si-IGBT at a certain moment. By continuously summing this value and dividing it by the total sampling time in real time, the turn-on loss of SiC-MOSFET and Si-IGBT can be obtained.

[0071] Step 4.5: Directly compare the square of the collected SiC-MOSFET on-current value with the on-resistance. Multiply by the sum of the two values ​​and then multiply by the sum of the two values ​​in a single sampling period to obtain the on-state energy loss of the SiC-MOSFET. By continuously summing this value and dividing it by the total sampling time in real time, the on-state energy loss of the SiC-MOSFET can be obtained.

[0072] Step 4.6: Compare the collected Si-IGBT on-state current value with the Si-IGBT on-state saturation voltage drop. Multiply by the sum of the two values ​​and then multiply by the sum of the two values ​​in a single sampling period to obtain the conduction energy loss of the Si-IGBT. By continuously summing this value and dividing it by the total sampling time in real time, the conduction loss of the Si-IGBT can be obtained.

[0073] Step 4.7: Combine the current value recorded as the off with the reverse conduction voltage drop V of the hybrid switch. F Multiply by the dead conduction time to calculate the energy loss during each reverse conduction. and By continuously summing this value and dividing it by the total acquisition time in real time, the dead zone loss of SiC / SiHyS can be obtained.

[0074] Step 4.8: Multiply the five loss values ​​obtained in steps 4.3-4.7 by the corresponding number of switches N to obtain the power loss of SiC-MOSFET and Si-IGBT respectively. Then add the five values ​​after multiplying by N to obtain the total power loss of the SiC / SiHyS converter device.

[0075] In step 5, the on-resistance of the SiC-MOSFET and the saturation on-state voltage drop of the Si-IGBT are estimated using the system thermal resistance and the power loss calculated in step 4, respectively, and updated in real time. and The value of .

[0076] Step 5: Calculate the junction temperature of the device based on the losses and update the SiC-MOSFET in real time. Values ​​and Si-IGBTs The value is used to obtain an accurate estimate of the loss, thus completing the estimation.

[0077] Example 2

[0078] This embodiment provides a method for estimating the losses of a hybrid switching converter based on a simulation model, specifically implemented according to the following steps: Step 1, select the SiC-MOSFET and Si-IGBT device models according to the system capacity; Step 2, perform parameter calibration for the SiC-MOSFET double-pulse test and the Si-IGBT pulse test according to the device models; Step 3, turn off the SiC-MOSFET and Si-IGBT in the SiC / SiHyS converter, and test the voltage drop V of the hybrid switch when the load current flows in reverse. F Step 4: Estimate the losses of the SiC / SiHyS converter based on the Matlab simulation model; Step 5: Calculate the junction temperature of the device based on the losses and update the SiC-MOSFET in real time. Values ​​and Si-IGBTs The value is used to obtain an accurate estimate of the loss, thus completing the estimation.

[0079] Example 3

[0080] This embodiment provides a method for estimating the losses of a hybrid switching converter based on a simulation model, specifically implemented according to the following steps: Step 1, select the SiC-MOSFET and Si-IGBT device models according to the system capacity; Step 2, perform parameter calibration for the SiC-MOSFET double-pulse test and the Si-IGBT pulse test according to the device models; Step 3, turn off the SiC-MOSFET and Si-IGBT in the SiC / SiHyS converter, and test the voltage drop V of the hybrid switch when the load current flows in reverse. F Step 4: Estimate the losses of the SiC / SiHyS converter based on the Matlab simulation model; Step 5: Calculate the junction temperature of the device based on the losses and update the SiC-MOSFET in real time. Values ​​and Si-IGBTs The value is used to obtain an accurate estimate of the loss, thus completing the estimation.

[0081] In step 2, the specific steps for parameter calibration using the SiC-MOSFET double-pulse test are as follows:

[0082] Loss functions of SiC-MOSFET turn-on and turn-off based on data curve fitting and The function coefficients are calibrated using the results of a commonly used double-pulse test.

[0083]

[0084]

[0085] Among them, V DC for and The corresponding DC bus voltage in the test conditions, V ds i is the drain-source voltage of the SiC-MOSFET. ds V is the drain-source on-state current of the SiC-MOSFET. DC_test The DC bus voltage applied during the double-pulse test experiment;

[0086] Based on data curve fitting, the function of SiC-MOSFET on-resistance versus junction temperature is expressed as follows: The parameters of the fitted function were calibrated through high and low temperature experiments.

[0087]

[0088] Among them, T j This is the junction temperature of the device.

[0089] In step 2, the specific steps for parameter calibration using the Si-IGBT pulse test are as follows:

[0090] Based on data curve fitting, the loss function of Si-IGBT turn-on and turn-off and The function coefficients are calibrated using commonly used pulse test results;

[0091]

[0092]

[0093] Based on data curve fitting, the function of Si-IGBT on-resistance and device junction temperature is expressed as follows: The parameters of the fitted function were calibrated through high and low temperature experiments.

[0094]

[0095] Among them, T j This is the junction temperature of the device.

[0096] The present invention provides a simulation model-based method for estimating the losses of hybrid switching converters. This method estimates losses based on the real-time voltage and current parameters of SiC-MOSFET and Si-IGBT, according to the system simulation model. It can meet the triggering models of the current six triggering modes of SiC / Si hybrid switches and will not become inapplicable due to changes in the triggering mode.

[0097] The estimation method of the present invention is universal and versatile, applicable not only to converters of any topology, but also to pure SiC-MOSFETs, pure Si-IGBTs and SiC / Si hybrid switches.

[0098] The estimation method of this invention includes feedback to adjust key parameters in real time, resulting in high accuracy in system loss estimation. The error will not increase due to changes in the system's operating electrical parameters. This invention is easy to integrate into the system. For multilevel converters where the electrical parameters of each device change significantly with the offset of system voltage / current, the proposed method of estimating system loss based on simulation model, detecting electrical parameters in real time, and automatically adjusting parameters in conjunction with feedback does not require complex switching functions and is easier to implement in practice.

Claims

1. A method for estimating the losses of a hybrid switching converter based on a simulation model, characterized in that, The specific steps are as follows: Step 1: Select the SiC-MOSFET and Si-IGBT device models according to the system capacity; Step 2: Perform parameter calibration for SiC-MOSFET dual-pulse test and Si-IGBT pulse test according to the device model; Step 3: Turn off the SiC-MOSFET and Si-IGBT in the SiC / SiHyS converter, and test the voltage drop of the hybrid switch when the load current flows in reverse. ; Step 4: Estimate the loss of the SiC / SiHyS converter based on the Matlab simulation model; Step 5: Calculate the junction temperature of the device based on the losses and update the SiC-MOSFET in real time. Values ​​and Si-IGBTs The value is used to obtain an accurate estimate of the loss, thus completing the estimation. In step 2, the specific steps for parameter calibration using the SiC-MOSFET double-pulse test are as follows: Loss functions of SiC-MOSFET turn-on and turn-off based on data curve fitting and The function coefficients are calibrated using the results of a commonly used double-pulse test. （1） （2） in, for and The DC bus voltage corresponds to the test conditions. This refers to the drain-source voltage of the SiC-MOSFET. This refers to the drain-source on-state current of the SiC-MOSFET. The DC bus voltage applied during the double-pulse test experiment; Based on data curve fitting, the function of SiC-MOSFET on-resistance versus junction temperature is expressed as follows: The parameters of the fitted function were calibrated through high and low temperature experiments. （3） Among them, T j This refers to the junction temperature of the device; In step 2, the specific steps for parameter calibration using the Si-IGBT pulse test are as follows: Based on data curve fitting, the loss function of Si-IGBT turn-on and turn-off and The function coefficients are calibrated using commonly used pulse test results. （4） （5） Based on data curve fitting, the functional relationship between Si-IGBT saturation on-state voltage drop and device junction temperature is expressed as follows: The parameters of the fitted function were calibrated through high and low temperature experiments. （6） Among them, T j This refers to the junction temperature of the device; Step 4 is detailed below: Step 4.1: Build a Matlab simulation model of the SiC / Si HyS converter and set up a module for detecting the hybrid switching voltage and device on-current. Step 4.2: The collected mixed switch terminal voltage is used to obtain the rising and falling edges of the current through a voltage comparator. The current corresponding to the rising edge of the voltage is recorded as the device turn-off current, and the current corresponding to the falling edge of the voltage is recorded as the device turn-on current. Step 4.3: Substitute the current value recorded as the turn-on value into equations (1) and (4), and multiply it by the single sampling time to calculate the turn-on energy loss of SiC-MOSFET and Si-IGBT at a certain moment. By continuously summing this value and dividing it by the total sampling time in real time, the turn-on loss of SiC-MOSFET and Si-IGBT can be obtained. Step 4.4: Substitute the current value recorded as the turn-off value into equations (2) and (5), and multiply it by the single sampling period to calculate the turn-off energy loss of SiC-MOSFET and Si-IGBT respectively. By continuously superimposing this value and dividing it by the total sampling time in real time, the turn-off loss of SiC-MOSFET and Si-IGBT can be obtained. Step 4.5: Directly compare the square of the collected SiC-MOSFET on-current value with the on-resistance. Multiply by the sum of the two values ​​and then multiply by the sum of the two values ​​in a single sampling period to obtain the on-state energy loss of the SiC-MOSFET. By continuously summing this value and dividing it by the total sampling time in real time, the on-state energy loss of the SiC-MOSFET can be obtained. Step 4.6: Compare the collected Si-IGBT on-state current value with the Si-IGBT saturation on-state voltage drop. Multiply by the sum of the two values ​​and then multiply by the sum of the two values ​​in real time to obtain the conduction energy loss of the Si-IGBT. By continuously summing this value and dividing it by the total acquisition time in real time, the conduction loss of the Si-IGBT can be obtained. Step 4.7: Combine the current value recorded as the off with the reverse conduction voltage drop of the hybrid switch. Multiply by the dead conduction time to calculate the energy loss during each reverse conduction. and The dead zone loss of SiC / SiHyS can be obtained by continuously summing this value and dividing it by the total acquisition time in real time. Step 4.8: Multiply the five loss values ​​obtained in steps 4.3-4.7 by the corresponding number of switches N to obtain the power loss of SiC-MOSFET and Si-IGBT respectively. Then add the five values ​​after multiplying by N to obtain the total power loss of the SiC / Si HyS converter device.

2. The method for estimating the losses of a hybrid switching converter based on a simulation model according to claim 1, characterized in that, In step 5, the on-resistance of the SiC-MOSFET and the saturation on-state voltage drop of the Si-IGBT are estimated using the system thermal resistance and the power loss calculated in step 4, respectively, and updated in real time. and The value of .

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