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CN-122026730-A - Full-power optimized modulation method for primary and secondary side fusion of 3L-DAB converter

CN122026730ACN 122026730 ACN122026730 ACN 122026730ACN-122026730-A

Abstract

The invention discloses a full-power optimized modulation method for primary and secondary side fusion of a 3L-DAB converter, belonging to the technical field of power electronic control; the invention firstly establishes a mathematical model of voltage transformation ratio, maximum current stress and soft switching condition, then calculates transmission power according to input and output voltage, carries out per unit treatment to construct a current stress objective function, then respectively searches phase shift ratio combination which minimizes the current stress in a range of applicable power of a secondary side and a primary side, and finally sends the optimized phase shift ratio into a pulse generator to generate a driving signal to control a switching tube.

Inventors

  • CHEN XIAOJIAO
  • HUANG LIANSHENG
  • LI ZHICHENG
  • ZHANG XIUQING
  • HE SHIYING
  • DOU SHENG
  • WANG ZEJING
  • ZUO YING
  • LI LINGPENG

Assignees

  • 中国科学院合肥物质科学研究院

Dates

Publication Date
20260512
Application Date
20260331

Claims (10)

  1. 1. The full-power optimized modulation method for the primary side and secondary side fusion of the 3L-DAB converter is characterized by comprising the following steps of: step 1, establishing a voltage conversion ratio of a 3L-DAB converter Maximum current stress Mathematical models of primary side soft switching conditions and secondary side soft switching conditions, wherein, ; Step 2, according to a given input voltage of the 3L-DAB converter Output voltage And transformer transformation ratio Calculating transmission power Maximum current stress And transmission power Performing per unit treatment to obtain per unit current stress And per unit transmission power Establishing a current stress objective function of the 3L-DAB converter; the formula of the current stress objective function of the 3L-DAB converter is as follows: Wherein, the As a function of the current stress objective, In order to be a lagrangian operator, In order to move the body inward, Is an outward shift phase; step 3, searching a phase shift ratio D 1 、D 2 combination which minimizes current stress in the applicable power ranges of the secondary side and the primary side respectively; the method for searching the phase shift ratio D 1 、D 2 combination which minimizes the current stress comprises the steps of adopting internal solution solving under the KKT condition in a high-power section to ensure that a single-side switching tube realizes current stress optimization and soft switching optimization; And 4, combining and sending the phase shift ratio D 1 、D 2 with the minimum current stress into a pulse generator to generate a driving signal to drive the on and off of a primary side switching tube and a secondary side switching tube of the 3L-DAB converter.
  2. 2. The method for optimizing modulation by fusion of full power of primary and secondary sides of a 3L-DAB converter according to claim 1, wherein the phase shift ratio D 1 、D 2 with minimum current stress corresponding to the applicable power range of the secondary side is specifically combined as follows: In the applicable power range In the above, the calculation formula of the phase shift ratio D 1 、D 2 combination with the minimum corresponding current stress is as follows: ; In the applicable power range In the interior, the calculation formula of the phase shift ratio D 1 、D 2 combination with the minimum corresponding current stress is 。
  3. 3. The method for optimizing and modulating the full power of the primary side and the secondary side of the 3L-DAB converter according to claim 1, wherein the phase shift ratio D 1 、D 2 with the minimum current stress corresponding to the applicable power range of the primary side is specifically combined as follows: In the applicable power range In the interior, the calculation formula of the phase shift ratio D 1 、D 2 combination with the minimum corresponding current stress is ; In the applicable power range In the interior, the calculation formula of the phase shift ratio D 1 、D 2 combination with the minimum corresponding current stress is 。
  4. 4. The full-power optimized modulation method for primary and secondary side fusion of a 3L-DAB converter according to claim 1, wherein the mathematical model is specifically as follows: The voltage transformation ratio expression is: Maximum current stress The expression of (2) is: The primary side soft switching conditions are as follows: the secondary side soft switching conditions are as follows: Wherein, the Is the input voltage of the 3L-DAB converter, Is the output voltage of the 3L-DAB converter, In order to achieve the transformation ratio of the transformer, Is that The current of the inductor is transmitted at the moment, For the switching tube frequency, In order to transmit the inductance of the inductor, In order to move the body inward, The phase shift ratio must satisfy the range for the outward shift 。
  5. 5. The method for optimizing modulation of primary and secondary side fusion full power of 3L-DAB converter as recited in claim 4, wherein said transmission power The formula of (2) is: 。
  6. 6. the method of 3L-DAB converter primary and secondary side fusion full power optimal modulation according to claim 4, wherein said per unit current stress The formula of (2) is: 。
  7. 7. The method for full power optimal modulation of primary and secondary side fusion of a 3L-DAB converter as recited in claim 4, wherein said per unit transmission power is The formula of (2) is: 。
  8. 8. A 3L-DAB converter, characterized in that the 3L-DAB converter primary-secondary side fusion full-power optimized modulation method according to any one of claims 1 to 7 is adopted to drive the on and off of a primary-secondary side switching tube.
  9. 9. An electronic device comprising a memory and a processor, wherein the memory is configured to store a program for supporting the processor to execute the 3L-DAB converter primary-secondary side fusion full-power optimized modulation method as recited in any one of claims 1 to 7, and the processor is configured to execute the program stored in the memory.
  10. 10. A storage medium having a computer program stored thereon, wherein the computer program when executed by a processor performs the steps of the 3L-DAB converter primary and secondary side fusion full power optimized modulation method as recited in any one of claims 1 to 7.

Description

Full-power optimized modulation method for primary and secondary side fusion of 3L-DAB converter Technical Field The invention belongs to the technical field of power electronic control, and relates to a full-power optimized modulation method for primary and secondary side fusion of a 3L-DAB (Three-level double-active bridge, three-Level Dual Active Bridge) converter. Background With the rapid development of energy structure transformation and distributed renewable energy sources, direct current conversion technology which is efficient, high in power density, electrically isolated and supports bidirectional energy flow is increasingly paid attention to. The double-active-bridge (Dual Active Bridge, DAB) converter has the advantages of high-frequency electrical isolation, easy realization of soft switch, flexible control of bidirectional power flow and the like, becomes one of core topologies of a medium-high-power isolated direct-current conversion system, and is widely applied to the fields of photovoltaic power generation, energy storage systems, electric automobile charging and the like. However, with the increase of the system voltage class and the power capacity, the conventional two-level DAB converter faces the problems of high voltage stress of the switching device, low modulation freedom and the like. Although the module can be used for improving the pressure endurance capacity in series, complex pressure equalizing control is introduced, and the system cost and the control difficulty are increased. Therefore, the three-level double-active-bridge (3L-DAB) converter has symmetrical primary and secondary side structures, can reduce the voltage stress of a switching tube to half of a two-level topology, and is suitable for medium-high voltage direct current distribution systems such as rail transit, ship power supply and the like. However, if the 3L-DAB converter includes up to 16 switching tubes, a conventional modulation strategy is adopted, which is prone to cause larger circulating current and switching current stress, increase conduction and switching loss, and even cause hard switching phenomenon, so that the system efficiency and reliability are affected. Therefore, a new modulation strategy is needed to effectively suppress the current stress in the full power range and maximize the zero-voltage turn-on of the switching tube, thereby improving the overall performance of the converter. Disclosure of Invention The technical scheme of the invention is used for solving the problem of effectively inhibiting the current stress of the 3L-DAB converter by optimizing the phase shift ratio. The invention solves the technical problems through the following technical scheme: The invention provides a full-power optimized modulation method for primary and secondary side fusion of a 3L-DAB converter, which comprises the following steps: step 1, establishing a voltage conversion ratio of a 3L-DAB converter Maximum current stressMathematical models of primary side soft switching conditions and secondary side soft switching conditions, wherein,; Step 2, according to a given input voltage of the 3L-DAB converterOutput voltageAnd transformer transformation ratioCalculating transmission powerMaximum current stressAnd transmission powerPerforming per unit treatment to obtain per unit current stressAnd per unit transmission powerEstablishing a current stress objective function of the 3L-DAB converter; the formula of the current stress objective function of the 3L-DAB converter is as follows: Wherein, the As a function of the current stress objective,In order to be a lagrangian operator,In order to move the body inward,Is an outward shift phase; step 3, searching a phase shift ratio D 1、D2 combination which minimizes current stress in the applicable power ranges of the secondary side and the primary side respectively; the method for searching the phase shift ratio D 1、D2 combination which minimizes the current stress comprises the steps of adopting internal solution solving under the KKT condition in a high-power section to ensure that a single-side switching tube realizes current stress optimization and soft switching optimization; And 4, combining and sending the phase shift ratio D 1、D2 with the minimum current stress into a pulse generator to generate a driving signal to drive the on and off of a primary side switching tube and a secondary side switching tube of the 3L-DAB converter. Further, the phase shift ratio D 1、D2 with the smallest current stress corresponding to the applicable power range of the secondary side is specifically combined as follows: In the applicable power range In the above, the calculation formula of the phase shift ratio D 1、D2 combination with the minimum corresponding current stress is as follows:; In the applicable power range In the interior, the calculation formula of the phase shift ratio D 1、D2 combination with the minimum corresponding current stress is。 Further, the phase shift