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CN-121984311-A - Resonant double-active-bridge converter and control method

CN121984311ACN 121984311 ACN121984311 ACN 121984311ACN-121984311-A

Abstract

The invention discloses a resonant double-active-bridge converter and a control method, wherein the converter comprises a primary full-bridge circuit, a secondary full-bridge or half-bridge circuit, a transformer and an LC resonant network formed by series resonant inductors and resonant capacitors, the control method comprises the following steps of obtaining parameters of input voltage V 1 , output voltage V 2 , transmission power P, transformer turn ratio N, resonant inductors L m and resonant capacitors C r of the converter, calculating primary fundamental wave equivalent voltage and secondary fundamental wave equivalent voltage, and calculating an internal shift angle alpha between a first bridge arm and a second bridge arm in the primary full-bridge circuit through the primary fundamental wave equivalent voltage and the secondary fundamental wave equivalent voltage. The method has the beneficial effects that the inherent defects of narrow gain range (usually only 0.8-1.2) of the traditional LLC converter and abrupt increase in circulation and abrupt decrease in efficiency of the traditional phase-shifting DAB when the voltage is seriously mismatched are fundamentally overcome.

Inventors

  • ZHANG YIPING
  • HU JIAWEI
  • YAN ZHENGCHAO

Assignees

  • 浙江华昱欣科技有限公司

Dates

Publication Date
20260505
Application Date
20260128

Claims (10)

  1. 1. The control method of the resonant double-active-bridge converter is characterized in that the converter comprises a primary full-bridge circuit, a secondary full-bridge or half-bridge circuit, a transformer and an LC resonant network consisting of a series resonant inductor and a series resonant capacitor, and the control method comprises the following steps: Parameters of input voltage V 1 , output voltage V 2 , transmission power P, transformer turn ratio N, resonant inductance L m and resonant capacitance C r of the converter are obtained; Calculating primary fundamental wave equivalent voltage and secondary fundamental wave equivalent voltage, and calculating the internal shift phase angle alpha between a first bridge arm and a second bridge arm in the primary full-bridge circuit through the primary fundamental wave equivalent voltage and the secondary fundamental wave equivalent voltage; calculating a secondary side external shift phase angle beta meeting zero voltage switching conditions based on the internal shift phase angle alpha; Calculating the switching frequency F s of the converter based on the acquired parameters and the internal shift angle alpha; And generating corresponding driving signals according to the internal shift phase angle alpha, the external shift phase angle beta and the switching frequency F s , and respectively controlling switching tubes of a primary full bridge and a secondary full bridge or a half bridge to realize power transmission.
  2. 2. The method of claim 1, wherein calculating the primary fundamental equivalent voltage and the secondary fundamental equivalent voltage comprises: The primary fundamental wave equivalent voltage is calculated as follows: ; the formula for calculating the secondary fundamental wave equivalent voltage is as follows: 。
  3. 3. The control method of a resonant double-active-bridge converter according to claim 2, wherein the calculation of the primary fundamental equivalent voltage and the secondary fundamental equivalent voltage to obtain the internal phase angle α between the first bridge arm and the second bridge arm in the primary full-bridge circuit includes the following formula: ; wherein K is a preset adjustment coefficient.
  4. 4. A control method of a resonant double active bridge converter according to claim 1, characterized in that calculating a secondary side out-shift phase angle β satisfying a zero voltage switching condition based on the in-shift phase angle α comprises: (1) Let intermediate variables ; (2) Constructing a first intermediate variable based on the primary fundamental equivalent voltage A, the secondary fundamental equivalent voltage B, the transformer turn ratio N, the internal shift phase angle alpha and the external shift phase angle beta Second intermediate variable ; (3) Constructing a function f (beta) about cos (beta), wherein the expression is as follows: ; (4) Solving equation f (beta) =0 to obtain a theoretical phase angle beta of the out-shift which meets the zero-voltage switching condition; (5) And determining the final external phase shift angle used in actual control as beta+omega, wherein omega is an adjustment quantity finely adjusted according to the real-time working condition.
  5. 5. The method of claim 4, wherein calculating the switching frequency F s of the converter based on the obtained parameter and the phase shift angle α comprises: Calculating an intermediate variable m based on the first intermediate variable a and the second intermediate variable b, wherein: ; Calculating an intermediate variable n, wherein: ; calculating a switching frequency Fs, wherein: 。
  6. 6. the method for controlling a resonant double-active-bridge converter according to claim 1, wherein the driving signal is generated by: The first pair of switching tubes (Q1, Q2) and the second pair of switching tubes (Q3, Q4) of the primary full bridge respectively output complementary square wave signals with the duty ratio of about 50%; the secondary full-bridge or half-bridge switching tubes (Q5, Q6, Q7, Q8 or Q5, Q6) output square wave signals which are synchronous with the primary square wave signals and have a duty ratio of about 50%; the internal shift phase angle alpha is the phase difference between the rising edge of the driving signal of the primary side switching tube Q1 and the rising edge of the driving signal of the switching tube Q4; The phase shift angle beta is the phase difference between the rising edge of the driving signal of the primary side switching tube Q1 and the rising edge of the driving signal of the secondary side switching tube Q5.
  7. 7. The method of claim 1, wherein the resonant capacitor C r comprises a parallel structure of a first capacitor C 1 and a second capacitor C 2 , and the capacitance value of the parallel structure is the sum of the capacities of the first capacitor C 1 and the second capacitor C 2 .
  8. 8. The control method of a resonant double-active-bridge converter according to claim 1, wherein when the secondary bridge arm is a full-bridge four-switch structure, power bidirectional transmission is realized, that is, power can be transmitted from a primary input voltage V 1 to a secondary output voltage V 2 , or from a secondary half-bridge, an output voltage V2 to a primary input voltage V1; When the secondary side bridge arm is a half bridge, unidirectional power transmission is realized, namely, power can be transmitted from the primary side input voltage V 1 to the secondary side output voltage V 2 .
  9. 9. A resonant double active bridge converter, comprising: control means configured to execute the control method according to any one of claims 1 to 8; the primary full-bridge circuit consists of a first switching tube Q1, a second switching tube Q2, a third switching tube Q3 and a fourth switching tube Q4; a secondary full bridge circuit or half bridge circuit; a transformer T1, the primary winding of which is connected to the alternating current output end of the primary full-bridge circuit; And the LC resonant network is connected in series in a primary winding or a secondary winding loop of the transformer T1 and comprises a resonant inductance Lm and a resonant capacitance Cr.
  10. 10. A resonant double active bridge converter according to claim 9, characterized in that the converter is a bi-directional power transfer topology, the secondary side employing a full bridge circuit consisting of four switching tubes (Q5, Q7, Q8); Or unidirectional power transmission topology, and a secondary side adopts a half-bridge circuit formed by two switching tubes (Q5 and Q6); the alternating current input ends of the fifth switching tube (Q5), the sixth switching tube (Q6), the seventh switching tube (Q7) and the eighth switching tube (Q8) are connected to the secondary winding of the transformer (T1) through the LC resonant network or directly.

Description

Resonant double-active-bridge converter and control method Technical Field The invention relates to the field of converter control, in particular to a resonant double-active-bridge converter and a control method. Background In the front-edge fields of new energy power generation, energy storage systems, data center power supply and the like, the isolated DC-DC converter is used as core power electronic equipment for realizing electric energy isolated conversion and transmission, and the performance of the isolated DC-DC converter directly determines the efficiency, reliability and application range of the whole system. The isolation type DC-DC conversion topology of the mainstream in the current industry is mainly divided into two types, namely a traditional LLC/CLLC converter based on a resonance mechanism and a common double-active-bridge (DAB) converter based on phase-shifting control. The common phase-shifting DAB converter has wide gain adjustment capability in theory, so that the common phase-shifting DAB converter becomes one of candidate schemes in a wide-voltage application scene. The core working principle is that the power transmission is realized by utilizing the triangular waveform of the inductive current by adjusting the phase shift angle of the switching tube of the bridge arm of the primary side and the secondary side. Meanwhile, the soft switch realizes the conditions of high dependence on voltage and load, when the ratio of the voltage mismatch is more than 2:1, the soft switch range can be rapidly deteriorated, the switch tube is easy to enter a hard off state, the on-loss and the device stress are obviously increased, serious electromagnetic interference problems are caused, the efficiency of the converter is finally reduced sharply in practical wide voltage application, the core requirements of wide gain adjustment, high efficiency and high reliability cannot be met, and the popularization and the application of the converter in the scenes of severe requirements of new energy, energy storage and the like on voltage fluctuation adaptability are severely limited. Disclosure of Invention The invention aims to solve the technical problems in the prior art and provide a resonant double-active-bridge converter and a control method. The application provides a control method of a resonant double-active-bridge converter, which comprises a primary full-bridge circuit, a secondary full-bridge or half-bridge circuit, a transformer, and an LC resonant network formed by series resonant inductors and resonant capacitors, wherein the control method comprises the following steps: Parameters of input voltage V 1, output voltage V 2, transmission power P, transformer turn ratio N, resonant inductance L m and resonant capacitance C r of the converter are obtained; Calculating primary fundamental wave equivalent voltage and secondary fundamental wave equivalent voltage, and calculating the internal shift phase angle alpha between a first bridge arm and a second bridge arm in the primary full-bridge circuit through the primary fundamental wave equivalent voltage and the secondary fundamental wave equivalent voltage; calculating a secondary side external shift phase angle beta meeting zero voltage switching conditions based on the internal shift phase angle alpha; Calculating the switching frequency F s of the converter based on the acquired parameters and the internal shift angle alpha; And generating corresponding driving signals according to the internal shift phase angle alpha, the external shift phase angle beta and the switching frequency F s, and respectively controlling switching tubes of a primary full bridge and a secondary full bridge or a half bridge to realize power transmission. Preferably, calculating the primary side fundamental equivalent voltage and the secondary side fundamental equivalent voltage includes: The primary fundamental wave equivalent voltage is calculated as follows: ; the formula for calculating the secondary fundamental wave equivalent voltage is as follows: 。 preferably, the internal shift phase angle alpha between the first bridge arm and the second bridge arm in the primary full-bridge circuit is obtained by calculating the primary fundamental wave equivalent voltage and the secondary fundamental wave equivalent voltage, and the internal shift phase angle alpha comprises the following formula: ; wherein K is a preset adjustment coefficient. Preferably, calculating the secondary side external phase shift angle beta satisfying the zero voltage switching condition based on the internal phase shift angle alpha includes: (1) Let intermediate variables ; (2) Constructing a first intermediate variable based on the primary fundamental equivalent voltage A, the secondary fundamental equivalent voltage B, the transformer turn ratio N, the internal shift phase angle alpha and the external shift phase angle betaSecond intermediate variable; (3) Constructing a function f (beta) about