Method and system for optimizing high-power interleaving Buck converter

Abstract

The invention relates to an optimization method and system for a high-power interleaving Buck converter, and the method comprises the steps: obtaining a variable set based on the parameter specification of the interleaving Buck converter; wherein the variable set comprises an inductive current average value, an inductance value, a duty ratio and an output capacitance value; inputting the variable set into an interleaving Buck converter circuit model, and calculating the total volume and the total loss of the converter; based on the total volume and the total loss, power density and efficiency under the parameter are obtained, and a design point is saved; and updating a parameter iteration design point, and obtaining the variable set again until the optimal power density and efficiency are obtained. According to the method, the optimal design parameters of the Buck converter are selected through comprehensive evaluation of the power density and efficiency of the design points.

Description

Technical Field

[0001] The present invention relates to the technical field of non-isolated DC-DC converters, and in particular to an optimization method and system for a high-power interleaved parallel Buck converter. Background Art

[0002] The non-isolated DC-DC topology is very flexible, suitable for miniaturization, and has inherent advantages in high power density application scenarios. At present, due to the rapid development of renewable energy such as solar photovoltaics and fuel cells, the application potential of DC microgrids is being gradually explored. There are similar DC microgrid systems on aircraft, so it is critical to optimize the power density and efficiency of high-power Buck converters.

[0003] The defects of the existing Buck converter design process include low efficiency, poor thermal management, high electromagnetic interference (EMI), slow dynamic response, improper component selection, unreasonable PCB layout, complex control strategy, high cost, low reliability and imperfect design tools. These problems lead to increased losses, overheating risks, noise interference, output voltage fluctuations, performance degradation, difficulty in implementation, increased costs, shortened life and insufficient design accuracy, affecting overall performance and reliability. Summary of the invention

[0004] In view of the defects of the prior art and the need for improvement, the present invention provides an optimization method and system for a high-power interleaved parallel Buck converter, the purpose of which is to propose an optimization method for iterative design parameters based on a circuit model, and to select the optimal design parameters of the Buck converter through a comprehensive evaluation of the power density and efficiency of the design point.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] An optimization method for a high-power interleaved parallel Buck converter, comprising:

[0007] Based on the parameter specifications of the interleaved parallel Buck converter, a variable set is obtained; wherein the variable set includes: an average value of the inductor current, an inductor value, a duty cycle, and an output capacitor value;

[0008] Inputting the variable set into the interleaved parallel Buck converter circuit model to calculate the total volume and total loss of the converter;

[0009] Based on the total volume and total loss, obtain the power density and efficiency under the parameters, and save the design point;

[0010] Update the parameter iteration design point and re-acquire the variable set until the optimized power density and efficiency are obtained.

[0011] Optionally, obtaining the variable set includes:

[0012]

[0013] Among them, I d is the average value of the inductor current, P o is the output power, n is the number of parallel phases, V in is the input voltage, L is the inductor value, r is the inductor current ripple rate, D is the duty cycle, f s is the switching frequency, V o is the output voltage, C is the output capacitor value, ΔV o is the output voltage ripple amplitude.

[0014] Optionally, calculating the total volume and total loss of the converter includes:

[0015] V all =V L +V C +V H

[0016] P all =P L +P C +P sw

[0017]

[0018] Among them, V H is the volume of the radiator, L, W are the length and width of the converter, H is the height of the radiator, P L is the inductor loss power, a, b, c are the loss parameters given in the core data sheet, B pk is the peak value of the inductor working magnetic flux density, V L is the volume given in the inductor data sheet, l is the length of the inductor winding, ρ cu is the copper resistivity, S wire is the cross-sectional area of ​​the winding wire, N is the number of turns of the inductor winding, l e is the magnetic path length given in the core data sheet, P C is the capacitor power loss, R ESR is the equivalent series resistance given in the capacitor data sheet, P SW is the power loss of the switch tube, E on , E off , P st , R on They are respectively the turn-on loss reference value, turn-off loss reference value, test power when the above two reference values ​​are obtained, and on-resistance given in the switch tube data sheet.

[0019] Optionally, obtaining power density and efficiency includes:

[0020]

[0021] Among them, ρ i is the power density at the design point, η i is the efficiency at this design point.

[0022] An optimization system for a high-power staggered parallel Buck converter, the system comprising: a variable acquisition module, a volume loss calculation module, a power density and efficiency calculation module, and an iteration module;

[0023] The variable acquisition module is used to acquire a variable set based on the parameter specifications of the interleaved parallel Buck converter; wherein the variable set includes: an average value of the inductor current, an inductor value, a duty cycle, and an output capacitor value;

[0024] The volume loss calculation module is used to input the variable set into the staggered parallel Buck converter circuit model to calculate the total volume and total loss of the converter;

[0025] The power density and efficiency calculation module is used to obtain the power density and efficiency under the parameters based on the total volume and total loss, and save the design point;

[0026] The iteration module is used to update the parameter iteration design point and reacquire the variable set until the optimal power density and efficiency are obtained.

[0027] Optionally, the variable acquisition module acquires the variable set including:

[0028]

[0029] Among them, I d is the average value of the inductor current, P o is the output power, n is the number of parallel phases, V in is the input voltage, L is the inductor value, r is the inductor current ripple rate, D is the duty cycle, f s is the switching frequency, V o is the output voltage, C is the output capacitor value, ΔV o is the output voltage ripple amplitude.

[0030] Optionally, the volume loss calculation module calculates the total volume and total loss of the converter, including:

[0031] V all =V L +V C +V H

[0032] P all =P L +P C +Psw

[0033]

[0034] Among them, V H is the volume of the radiator, L, W are the length and width of the converter, H is the height of the radiator, P L is the inductor loss power, a, b, c are the loss parameters given in the core data sheet, B pk is the peak value of the inductor working magnetic flux density, V L is the volume given in the inductor data sheet, l is the length of the inductor winding, ρ cu is the copper resistivity, S wire is the cross-sectional area of ​​the winding wire, N is the number of turns of the inductor winding, l e is the magnetic path length given in the core data sheet, P C is the capacitor power loss, R ESR is the equivalent series resistance given in the capacitor data sheet, P SW is the power loss of the switch tube, E on , E off , P st , R on They are respectively the turn-on loss reference value, turn-off loss reference value, test power when the above two reference values ​​are obtained, and on-resistance given in the switch tube data sheet.

[0035] Optionally, the power density and efficiency calculation module obtains the power density and efficiency including:

[0036]

[0037] Among them, ρ i is the power density at the design point, η i is the efficiency at this design point.

[0038] The beneficial effects of the present invention are:

[0039] The present invention first obtains a variable set based on the parameter specifications of the interleaved parallel Buck converter; secondly, the variable set is input into the circuit model of the interleaved parallel Buck converter to calculate the total volume and total loss of the converter; then, based on the total volume and total loss, the power density and efficiency under the parameters are obtained, and the design point is saved; finally, the parameter iteration design point is updated, and the variable set is re-obtained until the optimized power density and efficiency are obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0041] Figure 1 This is a flow chart of optimizing a high-power interleaved parallel Buck converter according to an embodiment of the present invention;

[0042] Figure 2 A 540V input, 270V output, 6kW three-phase staggered parallel Buck converter prototype designed according to the optimization process in an embodiment of the present invention;

[0043] Figure 3 The three-phase inductor current simulation waveform in the design process of the embodiment of the present invention;

[0044] Figure 4 1 is a waveform diagram of the half-bridge midpoint, output voltage, and output current during the test of the prototype according to an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

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

[0047] like Figure 1 As shown, this embodiment proposes an optimization method for a high-power interleaved parallel Buck converter, including:

[0048] Based on the parameter specifications of the interleaved parallel Buck converter, a variable set is obtained; wherein the variable set includes: average value of inductor current, inductor value, duty cycle, and output capacitor value;

[0049] Input the variable set into the interleaved parallel Buck converter circuit model and calculate the total volume and total loss of the converter;

[0050] Based on the total volume and total loss, the power density and efficiency under the parameter are obtained, and the design point is saved; wherein the parameter refers to the input variable set parameter under a certain design point during the iterative calculation process;

[0051] Update the parameter iteration design point and re-acquire the variable set until the optimized power density and efficiency are obtained.

[0052] The design point refers to the point where the current variable set takes values. Because there are four basic variables in the variable set, each variable has its own range of values. Changing the values ​​of one or more variables will result in different power density and efficiency. Therefore, the power density and efficiency calculated for each set of variable values ​​are called "design points". The iterative design point method is to fix three of the four basic variables and change the fourth variable with a certain step size. In this way, all variables are traversed in turn to obtain a set of design points, from which the optimal design point is selected.

[0053] Specifically, the present embodiment discloses an optimization method for a high-power interleaved parallel Buck converter, which is implemented in accordance with the following steps: Step 1, determining the parameter specifications of the interleaved parallel Buck converter according to the design requirements; Step 2, obtaining an input variable set from the above parameters; Step 3, substituting the interleaved parallel Buck converter circuit model into the circuit model, and calculating the total volume and total loss of the device according to the expressions of the circuit model; Step 4, obtaining the power density and efficiency under the parameters, and saving the design point; Step 5, updating the parameter iterative design point, and repeating the above steps until the optimized power density and efficiency design are obtained.

[0054] Step 2: Calculate according to the following formula:

[0055]

[0056] I d is the average value of the inductor current, P o is the output power, n is the number of parallel phases, V in is the input voltage, L is the inductor value, r is the inductor current ripple rate, D is the duty cycle, f s is the switching frequency, V o is the output voltage, C is the output capacitor value, ΔV o is the output voltage ripple amplitude. From the above formulas, we can get the constraint relationship between the input variable values, and thus find the input variable set.

[0057] Step 3: Calculate according to the following formula:

[0058]

[0059] V all =V L +V C +V H

[0060] P all =P L +P C+P sw

[0061] V H is the volume of the radiator, L, W are the length and width of the converter, H is the height of the radiator, P L is the inductor loss power, a, b, c are the loss parameters given in the core data sheet, B pk is the peak value of the inductor working magnetic flux density, V L is the volume given in the inductor data sheet, l is the length of the inductor winding, ρ cu is the copper resistivity, S wire is the cross-sectional area of ​​the winding wire, N is the number of turns of the inductor winding, l e is the magnetic path length given in the core data sheet, P C is the capacitor power loss, R ESR is the equivalent series resistance given in the capacitor data sheet, P SW is the power loss of the switch tube, E on , E off , P st , R on They are respectively the turn-on loss reference value, turn-off loss reference value, test power when the above two reference values ​​are obtained, and on-resistance given in the switch tube data sheet.

[0062] Step 4: Calculate according to the following formula:

[0063]

[0064] ρ i is the power density at the design point, η i is the efficiency at this design point.

[0065] This embodiment also proposes an optimization system for a high-power staggered parallel Buck converter, including: a variable acquisition module, a volume loss calculation module, a power density and efficiency calculation module, and an iteration module;

[0066] A variable acquisition module is used to acquire a variable set based on parameter specifications of the interleaved parallel Buck converter; wherein the variable set includes: an average value of the inductor current, an inductor value, a duty cycle, and an output capacitor value;

[0067] The volume loss calculation module is used to input the variable set into the interleaved parallel Buck converter circuit model to calculate the total volume and total loss of the converter;

[0068] Power density and efficiency calculation module, used to obtain the power density and efficiency under the parameters based on the total volume and total loss, and save the design point;

[0069] The iteration module is used to update the parameter iteration design point and reacquire the variable set until the optimal power density and efficiency are obtained.

[0070] Furthermore, the variable acquisition module acquires the variable set including:

[0071]

[0072] Among them, I d is the average value of the inductor current, P o is the output power, n is the number of parallel phases, V in is the input voltage, L is the inductor value, r is the inductor current ripple rate, D is the duty cycle, f s is the switching frequency, V o is the output voltage, C is the output capacitor value, ΔV o is the output voltage ripple amplitude.

[0073] Furthermore, the volume loss calculation module calculates the total volume and total loss of the converter including:

[0074] V all =V L +V C +V H

[0075] P all =P L +P C +P sw

[0076]

[0077] Among them, V H is the volume of the radiator, L, W are the length and width of the converter, H is the height of the radiator, P L is the inductor loss power, a, b, c are the loss parameters given in the core data sheet, B pk is the peak value of the inductor working magnetic flux density, V L is the volume given in the inductor data sheet, l is the length of the inductor winding, ρ cu is the copper resistivity, S wire is the cross-sectional area of ​​the winding wire, N is the number of turns of the inductor winding, l e is the magnetic path length given in the core data sheet, P C is the capacitor power loss, R ESR is the equivalent series resistance given in the capacitor data sheet, P SW is the power loss of the switch tube, E on , E off , P st , R on They are respectively the turn-on loss reference value, turn-off loss reference value, test power when the above two reference values ​​are obtained, and on-resistance given in the switch tube data sheet.

[0078] Furthermore, the power density and efficiency calculation module obtains the power density and efficiency including:

[0079]

[0080] Among them, ρ i is the power density at the design point, η i is the efficiency at this design point.

[0081] Figure 2 A three-phase interleaved parallel high power density Buck converter module designed according to the optimization method proposed in the present invention has an efficiency of 98.41% and a power density of 11.148kW / L after testing. Figure 3 The three-phase inductor current waveform is obtained by simulation software during the design of this type of Buck converter; Figure 4 Figure 2 shows the measured output voltage waveform (C2) and half-bridge midpoint switching waveform (C3) of this type of converter.

[0082] The embodiments described above are only descriptions of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. An optimization method for a high-power interleaved parallel Buck converter, characterized in that: include: Based on the parameter specifications of the interleaved parallel Buck converter, a variable set is obtained; wherein the variable set includes: an average value of the inductor current, an inductor value, a duty cycle, and an output capacitor value; Inputting the variable set into the interleaved parallel Buck converter circuit model to calculate the total volume and total loss of the converter; Based on the total volume and total loss, the power density and efficiency under the corresponding variables in the variable set are obtained, and the design point is saved; wherein the design point refers to the power density and efficiency calculated for each group of variable values; Update the variable iteration design point, fix three of the four variables in the variable set, change the fourth variable with a preset step size, traverse all variables in turn, re-acquire the variable set, and re-acquire the power density and efficiency under the corresponding variables until the optimized power density and efficiency are obtained.

2. The optimization method of high-power interleaved parallel Buck converter according to claim 1, characterized in that: Obtaining the variable set includes: Among them, I d is the average value of the inductor current, P o is the output power, n is the number of parallel phases, V in is the input voltage, L is the inductor value, r is the inductor current ripple rate, D is the duty cycle, f s is the switching frequency, V o is the output voltage, C is the output capacitor value, ΔV o is the output voltage ripple amplitude.

3. The optimization method of high-power interleaved parallel Buck converter according to claim 1, characterized in that: Calculation of the total volume and total losses of the converter includes: V all =V L +V C +V H P all =P L +P C +P sw Among them, V H is the volume of the radiator, L, W are the length and width of the converter, H is the height of the radiator, P L is the inductor loss power, a, b, c are the loss parameters given in the core data sheet, B pk is the peak value of the inductor working magnetic flux density, V L is the volume given in the inductor data sheet, l is the length of the inductor winding, ρ cu is the resistivity of copper, S wire is the cross-sectional area of ​​the winding wire, N is the number of turns of the inductor winding, l e is the magnetic path length given in the core data sheet, P C is the capacitor power loss, R ESR is the equivalent series resistance given in the capacitor data sheet, P SW is the power loss of the switch tube, E on , E off , P st , R on They are respectively the turn-on loss reference value, turn-off loss reference value, test power when the above two reference values ​​are obtained, and on-resistance given in the switch tube data sheet.

4. The optimization method of high-power interleaved parallel Buck converter according to claim 1, characterized in that: Obtaining power density and efficiency includes: Among them, ρ i is the power density at the design point, η i is the efficiency at this design point.

5. An optimization system for high-power interleaved parallel Buck converters, characterized in that: Used to implement the optimization method according to any one of claims 1 to 4, the system comprises: a variable acquisition module, a volume loss calculation module, a power density and efficiency calculation module, and an iteration module; The variable acquisition module is used to acquire a variable set based on the parameter specifications of the interleaved parallel Buck converter; wherein the variable set includes: an average value of the inductor current, an inductor value, a duty cycle, and an output capacitor value; The volume loss calculation module is used to input the variable set into the staggered parallel Buck converter circuit model to calculate the total volume and total loss of the converter; The power density and efficiency calculation module is used to obtain the power density and efficiency of the corresponding variables in the variable set based on the total volume and total loss, and save the design point; wherein the design point refers to the power density and efficiency calculated for each group of variable values; The iteration module updates the variable iteration design point by fixing three of the four variables in the variable set and changing the fourth variable with a preset step size, traversing all the variables in turn, re-obtaining the variable set, and re-obtaining the power density and efficiency under the corresponding variables until the optimized power density and efficiency are obtained.

6. The optimization system of high-power interleaved parallel Buck converter according to claim 5, characterized in that: The variable acquisition module acquires the variable set including: Among them, I d is the average value of the inductor current, P o is the output power, n is the number of parallel phases, V in is the input voltage, L is the inductor value, r is the inductor current ripple rate, D is the duty cycle, f s is the switching frequency, V o is the output voltage, C is the output capacitor value, ΔV o is the output voltage ripple amplitude.

7. The optimization system for high-power interleaved parallel Buck converters according to claim 5, characterized in that: The volume loss calculation module calculates the total volume and total loss of the converter, including: V all =V L +V C +V H P all =P L +P C +P sw Among them, V H is the volume of the radiator, L, W are the length and width of the converter, H is the height of the radiator, P L is the inductor loss power, a, b, c are the loss parameters given in the core data sheet, B pk is the peak value of the inductor working magnetic flux density, V L is the volume given in the inductor data sheet, l is the length of the inductor winding, ρ cu is the resistivity of copper, S wire is the cross-sectional area of ​​the winding wire, N is the number of turns of the inductor winding, l e is the magnetic path length given in the core data sheet, P C is the capacitor power loss, R ESR is the equivalent series resistance given in the capacitor data sheet, P SW is the power loss of the switch tube, E on , E off , P st , R on They are respectively the turn-on loss reference value, turn-off loss reference value, test power when the above two reference values ​​are obtained, and on-resistance given in the switch tube data sheet.

8. The optimization system for high-power interleaved parallel Buck converters according to claim 5, characterized in that: The power density and efficiency calculation module obtains the power density and efficiency by: Among them, ρ i is the power density at the design point, η i is the efficiency at this design point.

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