Power circuit parameter optimization method, device and system

Abstract

The application provides a power circuit parameter optimization method, device and system, and relates to the technical field of power electronics. The method comprises the following steps: establishing a circuit model library, a device model library, a device loss model and a running junction temperature model, and selecting a rated switching frequency and a power device model as circuit parameters to be optimized; selecting capacitors and magnetic elements according to capacitance values and inductance values; determining the loss of the device according to voltage values, current values, the rated switching frequency, the device model library and the device loss model; determining whether the circuit parameters meet the optimization design target according to the junction temperature and the upper limit of the device junction temperature; determining the weighted average values corresponding to each group of circuit parameters according to the total loss and the total volume respectively, and determining the circuit parameters corresponding to the minimum weighted average value as the optimal power circuit parameters. The power circuit parameters are optimized at the system level by taking the total volume and the total loss of the device as evaluation objects, which is beneficial to balancing the contradiction between the loss and the volume, and thus the efficient optimization of the power circuit parameters is realized.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and more specifically, to a method, apparatus, and system for optimizing power circuit parameters. Background Technology

[0002] Power electronic circuits can convert and control electrical energy, enabling it to supply power to loads in a suitable form. Classified by their energy conversion function, power electronic circuits can be categorized into four types: rectifier circuits, inverter circuits, AC converter circuits, and DC converter circuits. They are widely used in general industry, power systems, transportation, and household appliances, and are closely related to production and daily life.

[0003] Power circuits involve many components and have complex models. Traditional methods require multiple iterations of hardware circuit design to optimize power circuit parameters, which is time-consuming, costly, and inefficient. Summary of the Invention

[0004] The problem addressed by this invention is how to efficiently optimize power circuit parameters.

[0005] To address the aforementioned problems, this invention provides a power circuit parameter optimization method, comprising: establishing a circuit model library, a device model library, a device loss model, and an operating junction temperature model; selecting the rated switching frequency and power device model as the circuit parameters to be optimized; determining the capacitance and inductance values ​​corresponding to the rated switching frequency through the circuit model library, and selecting capacitors and magnetic components based on the capacitance and inductance values; obtaining the voltage and current values ​​of the devices through the circuit model library, and determining the device losses based on the voltage, current, rated switching frequency, device model library, and device loss model; determining the junction temperature of the devices based on the losses, device model library, and operating junction temperature model, and determining whether the circuit parameters meet the optimization design objective based on the junction temperature and the upper limit of the device junction temperature; determining the total loss and total volume corresponding to multiple sets of circuit parameters that meet the optimization design objective, and determining the weighted average value corresponding to each set of circuit parameters based on the total loss and total volume, and determining the circuit parameters corresponding to the minimum weighted average value as the optimal power circuit parameters.

[0006] The power circuit parameter optimization method described in this invention establishes a circuit model library, a device model library, a device loss model, and an operating junction temperature model. It selects the rated switching frequency and power device model as the circuit parameters to be optimized, and uses the total device volume and total loss as the evaluation objects to perform system-level optimization of the power circuit parameters. This helps to balance the contradiction between loss and volume, thereby achieving efficient optimization of power circuit parameters. Furthermore, it can optimize different power circuits, which improves the applicability of this invention.

[0007] Optionally, the circuit model library includes circuit models; the inputs of the circuit models include characteristic parameters, ripple boundary values, input voltage range, input current range, input power range, output voltage range, output current range, output power range, and rated switching frequency; the outputs of the circuit models include the voltage and current values ​​of each device under different operating conditions, as well as the capacitance and inductance values ​​corresponding to the ripple boundary values.

[0008] The power circuit parameter optimization method described in this invention optimizes power circuit parameters by setting the specific composition of the circuit model library and using the rated switching frequency and power device model as the circuit parameters to be optimized.

[0009] Optionally, determining the device loss based on the voltage value, the current value, the rated switching frequency, the device model library, and the device loss model includes: determining the conduction loss and switching loss generated when the power device is operating based on the voltage value, the current value, the rated switching frequency, the device model library, and the device loss model; determining the core loss based on the device loss model, the rated switching frequency, the device model library, and the Steinmetz formula; and determining the loss of the magnetic element based on the core loss.

[0010] The power circuit parameter optimization method of the present invention determines the conduction loss and switching loss generated when the power device is working, and determines the loss of the magnetic element based on the core loss to determine the total loss. Thus, the evaluation object can be determined based on the total loss to achieve power circuit parameter optimization.

[0011] Optionally, the device model library includes a SiC MOSFET device library, a Si MOSFET device library, an IGBT device library, and a diode device library. The step of determining the conduction loss and switching loss generated when the power device operates based on the voltage value, the current value, the rated switching frequency, the device model library, and the device loss model includes: determining the equivalent resistance of the power switching device and the forward voltage drop of the power diode, wherein the power switching device includes Si MOSFET, SiC MOSFET, and IGBT; determining the conduction loss of the power switching device based on the equivalent resistance of the conduction, and determining the conduction loss of the power diode based on the forward voltage drop; determining the voltage drop time when the power switching device is turned on and the voltage rise time when it is turned off; determining the turn-on loss and turn-off loss of the power switching device based on the voltage drop time and the voltage rise time, combined with the voltage value, current value, and rated switching frequency of the power switching device; determining the switching loss of the power switching device based on the turn-on loss and the turn-off loss; and using the reverse recovery loss of the power diode as the switching loss of the power diode.

[0012] The power circuit parameter optimization method of the present invention determines the total loss by determining the conduction loss and switching loss generated when the power device is working, thereby determining the evaluation object based on the total loss to achieve power circuit parameter optimization.

[0013] Optionally, determining the junction temperature of the device based on the loss, the device model library, and the running junction temperature model includes: determining the corresponding loss at ambient temperature, determining the initial device junction temperature based on the loss at ambient temperature; determining the loss after iteration based on the initial device junction temperature, determining the junction temperature after iteration based on the loss after iteration; and determining the junction temperature after iteration as the junction temperature of the device when the junction temperature difference between two iterations is less than a set value.

[0014] The power circuit parameter optimization method described in this invention determines the junction temperature of the device through two iterations, which is beneficial for achieving efficient optimization of power circuit parameters.

[0015] Optionally, determining whether the circuit parameters meet the optimization design objective based on the junction temperature and the upper limit of the device junction temperature includes: comparing the junction temperature of the device with the upper limit of the device junction temperature; when the junction temperature of the device is less than or equal to the upper limit of the device junction temperature, the circuit parameters meet the optimization design objective; when the junction temperature of the device is greater than the upper limit of the device junction temperature, the circuit parameters do not meet the optimization design objective, and the current circuit parameters are discarded.

[0016] The power circuit parameter optimization method described in this invention uses the upper limit of the operating junction temperature of the device as a screening condition for the corresponding circuit parameters to prevent the junction temperature from becoming too high, which is beneficial to the safety of the circuit.

[0017] Optionally, determining the total loss and total volume corresponding to multiple sets of circuit parameters that satisfy the optimization design objective includes: determining the total loss based on the loss of the power switching device, the loss of the power diode, and the loss of the magnetic element; and determining the total volume based on the volume of the power switching device, the volume of the power diode, the volume of the magnetic core of the magnetic element, and the volume of the capacitor.

[0018] The power circuit parameter optimization method described in this invention comprehensively considers the losses of power devices and magnetic components to determine the total loss, and comprehensively considers the volumes of power devices, magnetic components, and capacitors to determine the total volume, thereby achieving reasonable and efficient power circuit parameter optimization.

[0019] Optionally, determining the weighted average value corresponding to each group of circuit parameters based on the total loss and the total volume includes: determining a first weighted result based on the total loss and a first weighting coefficient; determining a second weighted result based on the total volume and a second weighting coefficient; and determining the weighted average value based on the first weighted result and the second weighted result.

[0020] The power circuit parameter optimization method described in this invention determines the weighted average value by considering total loss, total volume, and corresponding weighting coefficients. This helps to balance the contradiction between loss and volume, thereby achieving efficient optimization of power circuit parameters.

[0021] This invention also provides a power circuit parameter optimization device, comprising: a modeling module for establishing a circuit model library, a device model library, a device loss model, and an operating junction temperature model, and selecting a rated switching frequency and a power device model as the circuit parameters to be optimized; a setting module for determining the capacitance and inductance values ​​corresponding to the rated switching frequency through the circuit model library, and selecting capacitors and magnetic components based on the capacitance and inductance values; a loss module for obtaining the voltage and current values ​​of the device through the circuit model library, and determining the loss of the device based on the voltage, current, rated switching frequency, the device model library, and the device loss model; a junction temperature module for determining the junction temperature of the device based on the loss, the device model library, and the operating junction temperature model, and determining whether the circuit parameters meet the optimization design target based on the junction temperature and the upper limit of the device junction temperature; and an optimization module for determining the total loss and total volume corresponding to multiple sets of circuit parameters that meet the optimization design target, determining the weighted average value corresponding to each set of circuit parameters based on the total loss and the total volume, and determining the circuit parameters corresponding to the minimum weighted average value as the optimal power circuit parameters. The power circuit parameter optimization device and the power circuit parameter optimization method described above have the same advantages over the prior art, and will not be repeated here.

[0022] This invention also provides a power circuit parameter optimization system, including a computer-readable storage medium storing a computer program and a processor. The computer program is read and executed by the processor to implement the power circuit parameter optimization method described above. The advantages of this power circuit parameter optimization system over the prior art are the same as those of the aforementioned power circuit parameter optimization method, and will not be repeated here. Attached Figure Description

[0023] Figure 1 This is a flowchart illustrating the power circuit parameter optimization method according to an embodiment of the present invention.

[0024] Figure 2 This is a schematic diagram illustrating the iterative calculation of device loss and junction temperature in an embodiment of the present invention. Detailed Implementation

[0025] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0026] like Figure 1 As shown in the figure, this embodiment of the invention provides a power circuit parameter optimization method, including: establishing a circuit model library, a device model library, a device loss model, and an operating junction temperature model; selecting the rated switching frequency and power device model as the circuit parameters to be optimized; determining the capacitance and inductance values ​​corresponding to the rated switching frequency through the circuit model library, and selecting capacitors and magnetic components based on the capacitance and inductance values; obtaining the voltage and current values ​​of the devices through the circuit model library, and determining the device losses based on the voltage, current, rated switching frequency, device model library, and device loss model; determining the junction temperature of the devices based on the losses, device model library, and operating junction temperature model, and determining whether the circuit parameters meet the optimization design target based on the junction temperature and the upper limit of the device junction temperature; determining the total loss and total volume corresponding to multiple sets of circuit parameters that meet the optimization design target, and determining the weighted average value corresponding to each set of circuit parameters based on the total loss and total volume, and determining the circuit parameters corresponding to the minimum weighted average value as the optimal power circuit parameters.

[0027] Specifically, in this embodiment, the power circuit parameter optimization method includes: (i) establishing a circuit model library, a device model library, a device loss model, and an operating junction temperature model, and selecting the rated switching frequency and power device model as the circuit parameters to be optimized.

[0028] The circuit model library is used to store the numerical relationships between the voltage and current values ​​of each device in a power circuit and the input quantities.

[0029] The inputs to the circuit model include: characteristic parameters, ripple boundary values, input and output voltage / current / power, and rated switching frequency f. n Among them, characteristic parameters refer to parameters that cannot be changed during the circuit optimization process, including the drive resistance R of the switching devices. g , Switching device drive voltage V dri Radiator temperature T hs Parameters such as transformer turns ratio, ripple boundary value refers to the requirements of a branch in the circuit for voltage and current ripple, input and output voltage / current / power refer to the required operating range of the circuit, and for frequency modulation control circuits, rated switching frequency specifically refers to the resonant frequency.

[0030] The circuit model outputs include the voltage and current values ​​of each component under different operating conditions, as well as the capacitance and inductance values ​​corresponding to the ripple boundary values. Specifically, the output includes the current switching frequency f of the power circuit. swThe effective value of the current flowing through the switching device, I prms The average current I flowing through the switching device pav The voltage V that the switching device withstands when it is off. pds The current value I at the instant the switching device is turned on. pon The current value I at the instant the switching device is turned off. poff The effective value of the current flowing through the power diode, I Diorms The average current I flowing through the power diode Dioav Power diode reverse voltage value V RDio ; AP value of magnetic element; ΔB change in magnetic flux density of magnetic element within one cycle; C capacitance to meet ripple requirements. n Inductance L that meets ripple requirements n .

[0031] The device model library refers to the power device and passive device model library, including the SiC MOSFET device library, Si MOSFET device library, IGBT device library, diode device library, capacitor device library, and magnetic component device library.

[0032] For switching devices (Si MOSFET, SiCMosFET, IGBT), the device model library stores the following parameters obtained from datasheet analysis: the maximum on-state resistance R of the switching device at a junction temperature of 25℃. onmax (25℃); Temperature coefficient of on-state resistance α of switching devices R IGBT forward conduction threshold voltage V IGBT0 The charge Q required for a SiMoSfet to go from turn-off to full turn-on due to its gate-drain parasitic capacitance. gd The voltage value V corresponding to the Si MOSFET Miller plateau miller The current rise time t when the Si MOSFET is turned on ri The current fall time t when the Si MOSFET is turned off fi SiC MOSFETs or IGBTs withstand a voltage of V. ref The starting current is I ref The driving resistor is R gref Under the condition that the junction temperature of the device is 25℃, the single turn-on energy E of SiC MOSFET or IGBT on (V ref I ref P gref (25℃); SiC MOSFETs or IGBTs withstand a voltage of V ref The starting current is I ref The driving resistor is R grefUnder the condition that the junction temperature of the device is 25℃, the single turn-off energy E of SiC MOSFET or IGBT of (V ref I ref P gref (25℃); Normalized relationship function f of turn-on loss of SiC MOSFET or IGBT with respect to device withstand voltage. Von ();The normalized function f of SiCMosfet or IGBT turn-on loss with respect to turn-on current Ion ();The normalized function f of SiC MOSFET or IGBT turn-on loss with respect to drive resistance Ron ();The normalized function f of the turn-on loss of SiC MOSFET or IGBT with respect to the device junction temperature Ton ();The normalized function f of the turn-off loss of SiC MOSFET or IGBT with respect to the device withstand voltage Vof ();The normalized function f of the turn-off loss of SiC MOSFET or IGBT with respect to the turn-off current lof ();The normalized relationship function f of the turn-off loss of SiC MOSFET or IGBT with respect to the drive resistance Rof ();The normalized function f of the turn-off loss of SiC MOSFET or IGBT with respect to the device junction temperature Tof (); Upper limit of the operating junction temperature T of switching devices power-1 Thermal resistance R from the heat sink to the device housing hs-th-1 The thermal resistance R from the device case to the device PN junction th-jc-1 Volume V of a single switching device power .

[0033] For diodes, the device model library stores the following parameters: the maximum on-state resistance R of a power diode at 25℃. Diomax (25℃); Temperature coefficient of on-state resistance α of power diode RDio Power diode forward conduction threshold voltage V Dio0 ; Power diode reverse recovery charge Q rr The upper limit of the operating temperature T of a power diode power-2 Thermal resistance R from the heat sink to the device housing hs-th-2 The thermal resistance R from the device case to the device PN junction th-jc-2 The volume of a single power diode, V Dio .

[0034] For magnetic components, the device model library stores the following parameters: core AP value K. AP , is the product of the core cross-sectional area and the window area; core constant K c; The exponential relationship between core loss and switching frequency a1; The exponential relationship between core loss and change in magnetic flux density a2; The volume V of each core group mag .

[0035] For capacitors, the device model library stores the following parameters: capacitance value C; upper voltage limit V. Cmax Capacitor current limit I Cmax Single capacitor volume V cap .

[0036] (ii) Determine the capacitance and inductance values ​​corresponding to the rated switching frequency through the circuit model library, and select capacitors and magnetic components based on the capacitance and inductance values.

[0037] (iii) Obtain the voltage value that the device is subjected to and the current value that flows through the device through the circuit model library, and determine the loss of the device based on the voltage value, the current value, the rated switching frequency, the device model library and the device loss model.

[0038] Before obtaining the voltage and current values ​​flowing through the device, it is necessary to set the initial values ​​for the power circuit model library and the power device model library, specifically including:

[0039] (1) Select the appropriate power circuit model from the circuit model library, and set the required characteristic parameters and ripple boundary values, input and output voltage / current / power ranges, and rated switching frequency f of the power circuit model. n Optimization range. The characteristic parameters, ripple boundary values, and input / output voltage / current / power ranges are given values, determined at the beginning of the optimization design. The rated switching frequency f... n These are the circuit parameters to be optimized.

[0040] (2) Select the power devices to be analyzed and compared from the device model library, which are the circuit parameters to be optimized.

[0041] The circuit information, including the capacitance and inductance values ​​corresponding to the rated switching frequency, the voltage values ​​across the devices, and the current values ​​flowing through the devices, is obtained or calculated from the circuit model library. The circuit information extracted from the circuit model library specifically includes:

[0042] (1) The current rated switching frequency f is calculated from the ripple boundary values ​​in the circuit model library. n The capacitor C below n Inductance value L n .

[0043] (2) Obtain the voltage values ​​that the device withstands and the current values ​​that flow through the device under different circuit parameters from the circuit model library.

[0044] (3) Compare the passive device model library to select capacitors; calculate the AP value of magnetic components and select the magnetic core that is higher than and closest to the calculation result.

[0045] Device losses include the losses of power devices and the losses of magnetic components. Determining the losses of power devices and magnetic components specifically includes:

[0046] (1) The losses generated when power switching devices are in operation include conduction losses and switching losses.

[0047] The on-state equivalent resistance R of Si MOSFET, SiC MOSFET and IGBT Con The calculation is as follows:

[0048]

[0049] Among them, T j This represents the junction temperature of the device.

[0050] Switching device conduction loss P pC The calculation is as follows:

[0051]

[0052] The voltage drop time t when the Si MOSFET is turned on fu and voltage rise time t during turn-off ru It can be represented as:

[0053]

[0054]

[0055] Si MOSFET turn-on loss P SiMon Turn-off loss P SiMoff It can be represented as:

[0056]

[0057]

[0058] The switching losses of SiC MOSFETs or IGBTs can be calculated using the same algorithm, and the turn-on loss P SiCIGBTon Turn-off loss P SiCIGBToff It can be represented as:

[0059]

[0060]

[0061] Switching losses P of Si MOSFETs, SiC MOSFETs, and IGBTs in power circuitspsw It can be represented as:

[0062]

[0063] Switching device loss P ploss for:

[0064] P ploss =P pC +P psw

[0065] (2) The losses generated when power diode devices are working include conduction losses and switching losses.

[0066] The on-state equivalent resistance R of a power diode Dioon and on-state loss P CDio The calculation is as follows:

[0067]

[0068]

[0069] The switching loss of a power diode is mainly the reverse recovery loss P. Diorr The calculation is as follows:

[0070] P Diorr =f sw ·V RDio ·Q rr

[0071] Power diode device loss P Dioloss It can be represented as:

[0072] P Dioloss =P CDio +P Diorr

[0073] (3) The losses generated when magnetic components are working include core losses and copper losses. Since copper losses account for a small proportion and the actual length of the conductor is difficult to quantify, copper losses can generally be considered negligible.

[0074] Magnetic loss P per unit weight of ferrite core Fe It can be approximated using the Steinmetz formula:

[0075]

[0076] Since copper losses account for a small proportion and the actual length of the conductor is difficult to quantify, this proposal considers copper losses to be negligible. Therefore, the magnetic component loss P... mag It can be represented as:

[0077] P mag =P Fe

[0078] (iv) Determine the junction temperature of the device based on the loss, the device model library and the operating junction temperature model, and determine whether the circuit parameters meet the optimization design target based on the junction temperature and the upper limit of the device junction temperature.

[0079] The losses of Si MOSFETs, SiC MOSFETs, IGBTs, and power diodes are related to the device junction temperature. Device losses cause changes in junction temperature, which in turn lead to changes in device losses. Therefore, iterative calculations are needed to determine the relationship between the two losses until the difference between the two iterations is within an acceptable range. Figure 2 As shown, the device loss at the junction temperature is first calculated at ambient temperature to obtain the initial junction temperature. Then, the first iteration is performed, with the updated junction temperature corresponding to the new device parameters, thus calculating the loss and junction temperature after the first iteration. This process is repeated until the difference in junction temperature between two iterations is less than a set value; the result of this iteration is the final device loss and junction temperature.

[0080] Device junction temperature T j It can be represented as:

[0081] T j =T hs +P device ·(R hs-th +R th-jc )

[0082] Device loss P device It can be represented as:

[0083]

[0084] Thermal resistance R from heat sink to device housing hs-th It can be represented as:

[0085]

[0086] Thermal resistance R from device case to device PN junction th-jc It can be represented as:

[0087]

[0088] The junction temperature of the power switching device is compared with the upper limit of the device's operating junction temperature T. power-1 Compare the junction temperature of the power diode with the upper limit of its operating junction temperature T. power-2 If the values ​​are higher than the set values, it means that the current circuit parameters do not meet the power circuit parameter optimization design goals and should be discarded.

[0089] (v) Determine the total loss and total volume corresponding to multiple sets of circuit parameters that meet the optimization design objectives, and determine the weighted average value corresponding to each set of circuit parameters based on the total loss and the total volume. Determine the circuit parameters corresponding to the minimum weighted average value as the optimal power circuit parameters.

[0090] (1) Calculate the total volume loss P of all power devices and passive devices. loss and total volume V total .

[0091] P loss =∑P ploss +∑P Dioloss +∑P mag

[0092] V total =∑V power +∑V Dio +∑V mag +∑V cap

[0093] (2) Power device model and rated switching frequency f n The circuit parameters to be optimized are the total volume and total loss of power devices and passive devices, which are the evaluation objects. The total device volume V is obtained under different combinations of power devices. total and total loss P loss Regarding the rated switching frequency f n The relationship curve.

[0094] (3) The weighted average of the total device volume and total loss is calculated to obtain the weighted average ρ as follows:

[0095] ρ=α·P loss +β·V total

[0096] Where α and β are weighting coefficients.

[0097] Improving efficiency and reducing size are important goals in power circuit optimization design. Increased efficiency means lower losses and heat generation, while reduced size facilitates system miniaturization. Smaller size and lower losses indicate better circuit parameters. The circuit parameters corresponding to the minimum weighted average value ρ are the optimal power circuit parameters. There is a trade-off between high efficiency and small size in power circuits; increasing the rated switching frequency f... nWhile this approach helps reduce the size of passive components and thus the power circuit, it increases the difficulty of power circuit selection and also increases power circuit losses. Therefore, a weighted average is determined based on the total losses and total volume. This weighted average calculation method evaluates and balances the trade-off between losses and volume to obtain the optimal solution. This allows for efficient analysis and acquisition of the optimal design parameters for the power circuit under all operating conditions, thereby more effectively guiding the power circuit hardware design. In this embodiment, the circuit, power devices, and heat are integrated into a model library. Through standardized interfaces, a reusable tool for power device selection and heat dissipation evaluation is created.

[0098] Among them, the power circuit parameter optimization method can be applied to the power modules in new energy vehicles, including the on-board charger connecting the power grid and the high-voltage battery, the step-down circuit connecting the high and low voltage batteries, and the motor driver connecting the high-voltage battery and the motor. This helps to simplify the design of the thermal management system of new energy vehicles, improve the service life of devices, and realize the miniaturization of the power system of new energy vehicles, leaving more usable space for users. Small size means low weight, which is also beneficial for new energy vehicles to achieve a longer range.

[0099] In this embodiment, by establishing a circuit model library, a device model library, a device loss model, and an operating junction temperature model, the rated switching frequency and power device model are selected as the circuit parameters to be optimized. The total device volume and total loss are used as the evaluation objects to perform system-level optimization of the power circuit parameters. This helps to balance the contradiction between loss and volume, thereby achieving efficient optimization of power circuit parameters. Furthermore, it can optimize different power circuits, which is beneficial to improving the applicability of the present invention.

[0100] Optionally, the circuit model library includes circuit models; the inputs of the circuit models include characteristic parameters, ripple boundary values, input voltage range, input current range, input power range, output voltage range, output current range, output power range, and rated switching frequency; the outputs of the circuit models include the voltage and current values ​​of each device under different operating conditions, as well as the capacitance and inductance values ​​corresponding to the ripple boundary values.

[0101] Specifically, in this embodiment, when setting initial values, it is necessary to select the corresponding power circuit model from the circuit model library. Most of the input quantities of the circuit model are determined at the beginning of the optimization design and are used in subsequent calculations. The undetermined rated switching frequency and power device model are used as the circuit parameters to be optimized, thereby achieving efficient optimization of power circuit parameters.

[0102] In this embodiment, by setting the specific composition of the circuit model library, the rated switching frequency and power device model are used as the circuit parameters to be optimized, thereby achieving efficient optimization of power circuit parameters.

[0103] Optionally, determining the device loss based on the voltage value, the current value, the rated switching frequency, the device model library, and the device loss model includes: determining the conduction loss and switching loss generated when the power device is operating based on the voltage value, the current value, the rated switching frequency, the device model library, and the device loss model; determining the core loss based on the device loss model, the rated switching frequency, the device model library, and the Steinmetz formula; and determining the loss of the magnetic element based on the core loss.

[0104] Specifically, in this embodiment, the devices include power switching devices, power diodes, and magnetic components. When determining the losses, it is necessary to determine the conduction losses and switching losses generated when the power switching devices are working, the conduction losses and switching losses generated when the power diode devices are working, and the losses of the magnetic components. In this way, the evaluation object can be determined based on the total losses to achieve power circuit parameter optimization.

[0105] In this embodiment, the conduction loss and switching loss generated when the power device is working are determined, and the loss of the magnetic element is determined based on the core loss to determine the total loss. Thus, the evaluation object can be determined based on the total loss to achieve power circuit parameter optimization.

[0106] Optionally, the device model library includes a SiC MOSFET device library, a Si MOSFET device library, an IGBT device library, and a diode device library. The step of determining the conduction loss and switching loss generated when the power device operates based on the voltage value, the current value, the rated switching frequency, the device model library, and the device loss model includes: determining the equivalent resistance of the power switching device and the forward voltage drop of the power diode, wherein the power switching device includes Si MOSFET, SiC MOSFET, and IGBT; determining the conduction loss of the power switching device based on the equivalent resistance of the conduction, and determining the conduction loss of the power diode based on the forward voltage drop; determining the voltage drop time when the power switching device is turned on and the voltage rise time when it is turned off; determining the turn-on loss and turn-off loss of the power switching device based on the voltage drop time and the voltage rise time, combined with the voltage value, current value, and rated switching frequency of the power switching device; determining the switching loss of the power switching device based on the turn-on loss and the turn-off loss; and using the reverse recovery loss of the power diode as the switching loss of the power diode.

[0107] Specifically, in this embodiment, determining the conduction loss and switching loss generated when the power device is operating includes: determining the equivalent conduction resistance R of the power switching device and the power diode. Con According to R Con Calculate the on-state loss P of the switching device pCTaking Si MOSFET as an example, determine the voltage drop time t during turn-on. fu and voltage rise time t during turn-off fu Therefore, the turn-on loss P can be determined. SiMon Turn-off loss P SiMoff The switching losses are obtained by adding these together. For power diodes, the conduction losses can also be obtained through the on-state equivalent resistance R. Dioon To calculate, the switching loss is mainly the reverse recovery loss P. Diorr .

[0108] In this embodiment, the total loss is determined by identifying the conduction loss and switching loss generated when the power device is operating, thereby enabling the evaluation object to be determined based on the total loss to achieve power circuit parameter optimization.

[0109] Optionally, determining the junction temperature of the device based on the loss, the device model library, and the running junction temperature model includes: determining the corresponding loss at ambient temperature, determining the initial device junction temperature based on the loss at ambient temperature; determining the loss after iteration based on the initial device junction temperature, determining the junction temperature after iteration based on the loss after iteration; and determining the junction temperature after iteration as the junction temperature of the device when the junction temperature difference between two iterations is less than a set value.

[0110] Specifically, in this embodiment, combined with Figure 2 As shown, the device loss at the junction temperature is first calculated at ambient temperature to obtain the initial junction temperature. Then, the first iteration is performed, with the updated junction temperature corresponding to the new device parameters, thus calculating the loss and junction temperature after the first iteration. This process is repeated until the difference in junction temperature between two iterations is less than a set value; the result of this iteration is the final device loss and junction temperature.

[0111] In this embodiment, the junction temperature of the device is determined through two iterations, which is beneficial for achieving efficient optimization of power circuit parameters.

[0112] Optionally, determining whether the circuit parameters meet the optimization design objective based on the junction temperature and the upper limit of the device junction temperature includes: comparing the junction temperature of the device with the upper limit of the device junction temperature; when the junction temperature of the device is less than or equal to the upper limit of the device junction temperature, the circuit parameters meet the optimization design objective; when the junction temperature of the device is greater than the upper limit of the device junction temperature, the circuit parameters do not meet the optimization design objective, and the current circuit parameters are discarded.

[0113] Specifically, in this embodiment, the device junction temperature is compared with the upper limit of the device's operating junction temperature. If it is higher than the set value, it means that the current circuit parameters do not meet the power circuit parameter optimization design target and should be discarded.

[0114] In this embodiment, setting the upper limit of the device's operating junction temperature as a screening condition for the corresponding circuit parameters prevents the junction temperature from becoming too high, which is beneficial for protecting the circuit's safety.

[0115] Optionally, determining the total loss and total volume corresponding to multiple sets of circuit parameters that satisfy the optimization design objective includes: determining the total loss based on the loss of the power switching device, the loss of the power diode, and the loss of the magnetic element; and determining the total volume based on the volume of the power switching device, the volume of the power diode, the volume of the magnetic core of the magnetic element, and the volume of the capacitor.

[0116] Specifically, in this embodiment, the total loss is determined by the loss of the power switching device, the loss of the power diode, and the loss of the magnetic component, taking into account the losses of the power device and the magnetic component; the total volume is determined by the volume of the power switching device, the volume of the power diode, the volume of the magnetic core of the magnetic component, and the volume of the capacitor stored in the device model library, taking into account the volume of the power device, the magnetic component, and the capacitor, thereby achieving reasonable and efficient optimization of power circuit parameters.

[0117] In this embodiment, the total loss is determined by comprehensively considering the losses of power devices and magnetic components, and the total volume is determined by comprehensively considering the volumes of power devices, magnetic components, and capacitors, thereby achieving reasonable and efficient optimization of power circuit parameters.

[0118] Optionally, determining the weighted average value corresponding to each group of circuit parameters based on the total loss and the total volume includes: determining a first weighted result based on the total loss and a first weighting coefficient; determining a second weighted result based on the total volume and a second weighting coefficient; and determining the weighted average value based on the first weighted result and the second weighted result.

[0119] Specifically, in this embodiment, a first weighted result is determined based on the total loss and a first weighting coefficient; a second weighted result is determined based on the total volume and a second weighting coefficient; and a weighted average is determined based on the first weighted result and the second weighted result.

[0120] In this embodiment, the weighted average value is determined by the total loss, the total volume, and the corresponding weighting coefficients, which helps to balance the contradiction between loss and volume, thereby achieving efficient optimization of power circuit parameters.

[0121] Another embodiment of the present invention provides a power circuit parameter optimization device, comprising:

[0122] The modeling module is used to build circuit model libraries, device model libraries, device loss models, and operating junction temperature models, and selects the rated switching frequency and power device model as the circuit parameters to be optimized.

[0123] The setting module is used to determine the capacitance and inductance values ​​corresponding to the rated switching frequency through the circuit model library, and select capacitors and magnetic components based on the capacitance and inductance values;

[0124] The loss module is used to obtain the voltage and current values ​​of the device through the circuit model library, and determine the loss of the device based on the voltage value, the current value, the rated switching frequency, the device model library and the device loss model;

[0125] The junction temperature module is used to determine the junction temperature of the device based on the loss, the device model library, and the running junction temperature model, and to determine whether the circuit parameters meet the optimization design target based on the junction temperature and the upper limit of the device junction temperature.

[0126] An optimization module is used to determine the total loss and total volume corresponding to multiple sets of circuit parameters that meet the optimization design objective, determine the weighted average value corresponding to each set of circuit parameters based on the total loss and the total volume, and determine the circuit parameters corresponding to the minimum weighted average value as the optimal power circuit parameters.

[0127] Another embodiment of the present invention provides a power circuit parameter optimization system, including a computer-readable storage medium storing a computer program and a processor, wherein the computer program is read and executed by the processor to implement the power circuit parameter optimization method described above.

[0128] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A method for optimizing power circuit parameters, characterized in that, include: Establish a circuit model library, a device model library, a device loss model, and an operating junction temperature model, and select the rated switching frequency and power device model as the circuit parameters to be optimized; The capacitance and inductance values ​​corresponding to the rated switching frequency are determined using the circuit model library, and capacitors and magnetic components are selected based on the capacitance and inductance values. The voltage and current values ​​of the devices are obtained through the circuit model library, and the losses of the devices are determined based on the voltage values, the current values, the rated switching frequency, the device model library, and the device loss model. The junction temperature of the device is determined based on the loss, the device model library, and the operating junction temperature model. The circuit parameters are then determined to meet the optimization design objectives based on the junction temperature and the upper limit of the device junction temperature. Determine the total loss and total volume corresponding to multiple sets of circuit parameters that meet the optimization design objective, and determine the weighted average value of each set of circuit parameters based on the total loss and the total volume. Determine the circuit parameters corresponding to the minimum weighted average value as the optimal power circuit parameters. The step of determining the junction temperature of the device based on the loss, the device model library, and the operating junction temperature model includes: The corresponding loss is determined at the ambient temperature, and the initial device junction temperature is determined based on the loss at the ambient temperature; The loss after iteration is determined based on the initial device junction temperature, and the junction temperature after iteration is determined based on the loss after iteration. When the junction temperature difference between two iterations is less than a set value, the junction temperature after the iteration is determined as the junction temperature of the device.

2. The power circuit parameter optimization method according to claim 1, characterized in that, The circuit model library includes circuit models; The inputs to the circuit model include characteristic parameters, ripple boundary values, input voltage range, input current range, input power range, output voltage range, output current range, output power range, and rated switching frequency. The output of the circuit model includes the voltage and current values ​​of each device under different operating conditions, as well as the capacitance and inductance values ​​corresponding to the ripple boundary values.

3. The power circuit parameter optimization method according to claim 2, characterized in that, The step of determining the device loss based on the voltage value, the current value, the rated switching frequency, the device model library, and the device loss model includes: The conduction loss and switching loss generated by the power device during operation are determined based on the voltage value, the current value, the rated switching frequency, the device model library, and the device loss model. The core loss is determined based on the device loss model, the rated switching frequency, the device model library, and the Steinmetz formula. The loss of the magnetic element is then determined based on the core loss.

4. The power circuit parameter optimization method according to claim 3, characterized in that, The device model library includes a SiC MOSFET device library, a Si MOSFET device library, an IGBT device library, and a diode device library. The step of determining the conduction loss and switching loss generated by the power device during operation based on the voltage value, the current value, the rated switching frequency, the device model library, and the device loss model includes: Determine the on-state equivalent resistance of power switching devices and the forward voltage drop of power diodes, wherein the power switching devices include Si MOSFETs, SiC MOSFETs, and IGBTs; The on-state loss of the power switching device is determined based on the on-state equivalent resistance, and the on-state loss of the power diode is determined based on the forward voltage drop. Determine the voltage drop time when the power switching device is turned on and the voltage rise time when it is turned off. Based on the voltage drop time and the voltage rise time, and in combination with the voltage value, current value and rated switching frequency of the power switching device, determine the turn-on loss and turn-off loss of the power switching device. Based on the turn-on loss and the turn-off loss, determine the switching loss of the power switching device. The reverse recovery loss of the power diode is taken as the switching loss of the power diode.

5. The power circuit parameter optimization method according to claim 1, characterized in that, The step of determining whether the circuit parameters meet the optimization design target based on the junction temperature and the upper limit of the device junction temperature includes: comparing the junction temperature of the device with the upper limit of the device junction temperature; when the junction temperature of the device is less than or equal to the upper limit of the device junction temperature, the circuit parameters meet the optimization design target; when the junction temperature of the device is greater than the upper limit of the device junction temperature, the circuit parameters do not meet the optimization design target, and the current circuit parameters are discarded.

6. The power circuit parameter optimization method according to claim 5, characterized in that, The determination of the total loss and total volume corresponding to the multiple sets of circuit parameters that satisfy the optimization design objective includes: The total loss is determined based on the losses of the power switching device, the power diode, and the magnetic component. The total volume is determined based on the volume of the power switching device, the volume of the power diode, the volume of the magnetic core of the magnetic element, and the volume of the capacitor.

7. The power circuit parameter optimization method according to claim 6, characterized in that, The step of determining the weighted average value of each group of circuit parameters based on the total loss and the total volume includes: The first weighting result is determined based on the total loss and the first weighting coefficient; The second weighting result is determined based on the total volume and the second weighting coefficient; The weighted average value is determined based on the first weighted result and the second weighted result.

8. A power circuit parameter optimization device, characterized in that, include: The modeling module is used to build circuit model libraries, device model libraries, device loss models, and operating junction temperature models, and selects the rated switching frequency and power device model as the circuit parameters to be optimized. The setting module is used to determine the capacitance and inductance values ​​corresponding to the rated switching frequency through the circuit model library, and select capacitors and magnetic components based on the capacitance and inductance values; The loss module is used to obtain the voltage and current values ​​of the device through the circuit model library, and determine the loss of the device based on the voltage value, the current value, the rated switching frequency, the device model library and the device loss model; The junction temperature module is used to determine the junction temperature of the device based on the loss, the device model library, and the running junction temperature model, and to determine whether the circuit parameters meet the optimization design target based on the junction temperature and the upper limit of the device junction temperature. The optimization module is used to determine the total loss and total volume corresponding to multiple sets of circuit parameters that meet the optimization design objectives, determine the weighted average value corresponding to each set of circuit parameters based on the total loss and the total volume, and determine the circuit parameters corresponding to the minimum weighted average value as the optimal power circuit parameters. The step of determining the junction temperature of the device based on the loss, the device model library, and the operating junction temperature model includes: The corresponding loss is determined at the ambient temperature, and the initial device junction temperature is determined based on the loss at the ambient temperature; The loss after iteration is determined based on the initial device junction temperature, and the junction temperature after iteration is determined based on the loss after iteration. When the junction temperature difference between two iterations is less than a set value, the junction temperature after the iteration is determined as the junction temperature of the device.

9. A power circuit parameter optimization system, characterized in that, The method includes a computer-readable storage medium storing a computer program and a processor, the computer program being read and executed by the processor to implement the power circuit parameter optimization method as described in any one of claims 1 to 7.

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