李善壽，王 浩，葉 偉，方潛生，顏 普

抑制DAB變換器回流功率的雙重移相調(diào)制策略

李善壽1，王 浩1，葉 偉2，方潛生1，顏 普1

(1.安徽建筑大學(xué)智能建筑與建筑節(jié)能安徽省重點實驗室，安徽 合肥 230022；2.安徽南瑞繼遠電網(wǎng)技術(shù)有限公司，安徽 合肥 230088)

雙有源橋(Dual Active Bridge, DAB)變換器在傳統(tǒng)雙重移相(Dual Phase Shift, DPS)調(diào)制下，變壓器兩側(cè)電壓不匹配時，中小功率區(qū)域內(nèi)回流功率較大。針對以上問題，提出一種抑制回流功率的雙重移相(Dual Phase Shift for Reactive Power Suppression, DPS-RPS)調(diào)制策略。首先對DPS-RPS調(diào)制的工作原理進行分析并建立數(shù)學(xué)模型，基于該模型對電流應(yīng)力進行優(yōu)化。然后在電流應(yīng)力最小化條件下分別對DPS調(diào)制和DPS-RPS調(diào)制的回流功率及電流應(yīng)力大小進行對比。結(jié)果表明，相比較于DPS調(diào)制，DPS-RPS調(diào)制在中小功率區(qū)域內(nèi)減小了回流功率的同時降低了電流應(yīng)力。最后通過實驗驗證了所提DPS-RPS調(diào)制的可行性及有效性。

雙有源橋變換器；雙重移相；回流功率；電力應(yīng)力

0 引言

儲能系統(tǒng)是解決可再生能源發(fā)電間歇性及隨機波動性的有效途徑[1-4]，雙向DC-DC變換器是儲能系統(tǒng)的重要組成部分[5-8]，雙有源橋(Dual Active Bridge, DAB)變換器由于具有功率密度高、電氣隔離、能量雙向流動等特點，是雙向DC-DC變換器的基本拓撲結(jié)構(gòu)之一，SPS(Single Phase Shift)調(diào)制是DAB變換器的基本控制策略[9-13]，然而SPS調(diào)制下存在較大回流功率及電流應(yīng)力，整體效率偏低。

為提高DAB變換器的轉(zhuǎn)換效率，相關(guān)文獻對電流應(yīng)力、回流功率及軟開關(guān)等方面展開研究[14-17]。文獻[18]對兩控制變量的傳統(tǒng)DPS(Dual Phase Shift)調(diào)制的研究表明，傳統(tǒng)DPS調(diào)制下的變換器工作效率明顯優(yōu)于SPS調(diào)制，然而并沒有對回流功率進一步優(yōu)化。文獻[19]提出了傳統(tǒng)DPS調(diào)制下電流應(yīng)力優(yōu)化方法，然而并沒有涉及對回流功率的分析。針對回流功率問題，文獻[20]提出了一種雙重雙向內(nèi)移相調(diào)制下最小回流功率控制策略，但僅在電壓傳輸比為1時進行了分析，并不具備普遍性。文獻[21]研究了DPS調(diào)制下全功率范圍軟開關(guān)的實現(xiàn)條件，然而通過軟開關(guān)優(yōu)化在中低負載區(qū)域內(nèi)會使電流應(yīng)力大幅增加，降低了變換器工作效率，且同樣沒有涉及回流功率的優(yōu)化。文獻[22-23]研究了具有三控制變量的三重移相(Triple Phase Shift, TPS)調(diào)制方法，然而TPS控制方法分析復(fù)雜，工程應(yīng)用中難以實現(xiàn)。

為進一步提高DAB變換器的轉(zhuǎn)化效率，本文從回流功率的角度出發(fā)進行研究，通過改變傳統(tǒng)DPS調(diào)制的內(nèi)移相方式，改變回流功率的作用時間，提出DPS-RPS(Dual Phase Shift for Reactive Power Suppression)調(diào)制策略，首先分析DPS-RPS調(diào)制的工作原理并建立數(shù)學(xué)模型，利用所建立的數(shù)學(xué)模型對電力應(yīng)力進行優(yōu)化，然后對比研究了不同工況下電流應(yīng)力最優(yōu)時DPS及DPS-RPS調(diào)制下回流功率及電感電流峰值大小。最后搭建以TMS320F28335為核心控制器的DAB變換器數(shù)字控制實驗平臺，對理論分析進行實驗驗證。

1 DAB變換器原理及回流功率特性分析

1.1 DAB變換器拓撲結(jié)構(gòu)

圖1 DAB變換器拓撲

1.2 SPS調(diào)制原理

下文所涉及標(biāo)幺化表達式均以式(2)作為基準(zhǔn)。

1.3 DPS調(diào)制原理及回流功率特性分析

兩種模式下電感電流峰值標(biāo)幺化表達式均為

2 抑制回流功率的雙重移相調(diào)制策略

2.1 DPS-RPS調(diào)制基本原理

2.2 DPS-RPS調(diào)制工作原理分析

以DPS-RPS調(diào)制模式1為例，對DPS-RPS的工作原理進行分析，忽略系統(tǒng)損耗，并認為所有開關(guān)器件都是理想開關(guān)器件，根據(jù)伏秒原理，在一個周期內(nèi)，DPS-RPS調(diào)制下變換器工作波形具有對稱性，本文僅分析前半個周期的工作原理，后半周期的分析相同，具體如下。

2.3 DPS-RPS調(diào)制策略的數(shù)學(xué)模型

求得DPS-RPS調(diào)制模式1的傳輸功率表達式為

對式(12)、式(13)標(biāo)幺化得到

DPS-RPS調(diào)制模式2的分析同模式1，得到模式2各個時刻的電感電流表達式為

同理得到模式2電流峰值及傳輸功率標(biāo)幺化表達式為

3 電流應(yīng)力優(yōu)化對回流功率的影響

3.1 電流應(yīng)力最優(yōu)的移相比求解方法

根據(jù)文獻[28]，建立電流應(yīng)力最優(yōu)時移相比的求解公式，如式(20)所示。

分別將式(14)、式(15)及式(6)代入式(17)和式(18)，求得DPS-RPS調(diào)制策略下模式1及模式2的電流應(yīng)力最優(yōu)移相比分別為

以上分析表明DPS-RPS調(diào)制只能在中小功率區(qū)域內(nèi)(標(biāo)幺化功率0～0.667)對電流應(yīng)力進行優(yōu)化。

將式(3)、式(4)代入式(20)，求得DPS調(diào)制下模式1及模式2的最優(yōu)移相比分別為

3.2 電流應(yīng)力最優(yōu)條件下回流功率對比分析

3.2.1 DPS-RPS調(diào)制回流功率特性分析

3.2.2 DPS調(diào)制回流功率特性分析

將式(24)、式(25)代入式(5)，得到DPS調(diào)制電流應(yīng)力優(yōu)化后的回流功率為

3.2.3 DPS-RPS及DPS調(diào)制下回流功率對比分析

圖5 優(yōu)化后回流功率對比

3.3 電流應(yīng)力對比分析

分別將DPS-RPS的最優(yōu)移相比表達式(21)、式(22)代入式(14)、式(17)，得到DPS-RPS調(diào)制下電流應(yīng)力優(yōu)化后電感電流峰值為

將式(24)、式(25)代入式(4)得到DPS控制下優(yōu)化后的電流峰值為

圖6 優(yōu)化后電流應(yīng)力對比

4 實驗驗證

4.1 實驗條件

為驗證所提DPS-RPS調(diào)制策略的可行性及相關(guān)理論分析的準(zhǔn)確性，根據(jù)文獻[29]的DAB閉環(huán)控制方法，搭建了以TMS320F28335為核心控制器件的DAB變換器閉環(huán)控制實驗平臺進行實驗驗證。

表1 實驗平臺參數(shù)

4.2 實驗結(jié)果分析

圖7 輸出電壓為30 V、負載為10 W實驗波形

圖8 輸出電壓為40 V、負載為10 W實驗波形

圖9輸出電壓為30 V、負載為5 W實驗波形

圖10 輸出電壓為40 V、負載為5 W實驗波形

5 結(jié)論

針對DAB變換器在傳統(tǒng)DPS調(diào)制下中小功率區(qū)域內(nèi)回流功率較大的問題，對傳統(tǒng)DPS調(diào)制進行了改進，提出了一種抑制回流功率的雙重移相調(diào)制策略(DPS-RPS)，通過改變傳統(tǒng)DPS調(diào)制的內(nèi)移相方式，減小了回流功率的作用時間來抑制回流功率。并通過理論分析與實驗驗證，證明所提DPS-RPS調(diào)制策略的有效性。本文所提方法減小回流功率的同時降低了電流應(yīng)力，可推廣至DAB變換器提高中小功率區(qū)域的轉(zhuǎn)換效率應(yīng)用中。

論文后續(xù)將進一步研究高功率區(qū)域回流功率及電流應(yīng)力的優(yōu)化方法。

[1] CHANDAK S, BHOWMIK P, ROUT P K. Load shedding strategy coordinated with storage device and D-STATCOM to enhance the microgrid stability[J]. Protection and Control of Modern Power Systems, 2019, 4(3): 250-268.

[2] 尉耀穩(wěn), 李躍龍, 陳思超, 等. 多類型源儲協(xié)調(diào)互動的配電網(wǎng)分布魯棒優(yōu)化調(diào)度[J]. 電力工程技術(shù), 2021, 40(5): 192-199.

YU Yaowen, LI Yuelong, CHEN Sichao, et al. Distributionally robust optimal dispatch of distribution network considering multiple source-storage coordinated interaction[J].Electric Power Engineering Technology, 2021, 40(5): 192-199.

[3] 孫偉卿, 羅靜, 張婕. 高比例風(fēng)電接入的電力系統(tǒng)儲能容量配置及影響因素分析[J]. 電力系統(tǒng)保護與控制, 2021, 49(15): 9-18.

SUN Weiqing, LUO Jing, ZHANG Jie. Energy storage capacity allocation and influence factor analysis of power system with high proportion of wind power[J]. Power System Protection and Control, 2021, 49(15): 9-18.

[4] 王晨, 李海軍, 徐光福, 等. 含多元儲能交直流混合微電網(wǎng)系統(tǒng)控制策略研究[J]. 供用電, 2020, 37(6): 74-81.

WANG Chen, LI Haijun, XU Guangfu, et al. Research on control strategy of AC/DC hybrid microgrid system with multi-type energy storage[J]. Distribution & Utilization, 2020, 37(6): 74-81.

[5] 宋春寧, 付棟, 李欣. 雙向全橋DC/DC變換器在直流微電網(wǎng)中的應(yīng)用[J]. 電測與儀表, 2020, 57(18): 128-132.

SONG Chunning, FU Dong, LI Xin. Application of bi-directional full-bridge DC/DC converter in DC micro-grid[J]. Electrical Measurement & Instrumentation, 2020, 57(18): 128-132.

[6] 陳天錦, 牛高遠, 甘江華, 等. 基于虛擬同步策略的電動汽車V2G充放電系統(tǒng)研究及樣機實現(xiàn)[J]. 電力系統(tǒng)保護與控制, 2021, 49(3): 131-141.

CHEN Tianjin, NIU Gaoyuan, GAN Jianghua, et al. Research and prototype manufacture on electric vehicle V2G systems based on virtual synchronous control strategy[J]. Power System Protection and Control, 2021, 49(3): 131-141.

[7] 孫元崗, 同向前, 李庚, 等. 一種雙向諧振型高頻直流變壓器通用參數(shù)設(shè)計方法[J]. 電力系統(tǒng)保護與控制, 2021, 49(5): 29-35.

SUN Yuangang, TONG Xiangqian, LI Geng, et al. A generalized parameter design approach for bidirectional resonant high frequency DC transformer[J]. Power System Protection and Control, 2021, 49(5): 29-35.

[8] 李磊, 陶駿, 朱明星, 等. 基于超級電容儲能型MMC的控制策略[J]. 中國電力, 2020, 53(11): 15-22.

LI Lei, TAO Jun, ZHU Mingxing, et al. Control strategy for MMC based on super-capacitor energy storage[J]. Electric Power, 2020, 53(11): 15-22.

[9] 許正平, 李俊. 雙向全橋DC-DC變換器高效能控制研究與實現(xiàn)[J]. 電力系統(tǒng)保護與控制, 2016, 44(2): 140-146.

XU Zhengping, LI Jun. Research and implementation of bidirectional full bridge DC-DC converter with high efficiency control[J]. Power System Protection and Control, 2016, 44(2): 140-146.

[10] XU G, LI L, CHEN X, et al. Optimized EPS control to achieve full load range ZVS with seamless transition for dual active bridge converters[J]. IEEE Transactions on Industrial Electronics, 2021, 68(9): 8379-8390.

[11] BAI H, MI C. Eliminate reactive power and increase system efficiency of isolated bidirectional dual-active-bridge DC-DC converters using novel dual-phase-shift control[J]. IEEE Transactions on Power Electronics, 2008, 23(6): 2905-2914.

[12] 伏祥運, 湯國晟, 崔紅芬, 等. 基于DAB的光儲型混合系統(tǒng)功率調(diào)節(jié)與控制[J]. 電力科學(xué)與技術(shù)學(xué)報, 2020, 35(6): 138-143.

FU Xiangyun, TANG Guosheng, CUI Hongfen, et al. Study on power regulation and control based on DAB for a hybrid system with photovoltaic and storage[J]. Journal of Electric Power Science and Technology, 2020, 35(6): 138-143.

[13] 張哲, 許崇福, 王弋飛, 等. 多電平直流鏈電力電子變壓器控制策略研究[J]. 電力工程技術(shù), 2020, 39(4): 9-15.

ZHANG Zhe, XU Chongfu, WANG Yifei, et al. Control strategies for the multi-level DC-link power electronic transformer[J]. Electric Power Engineering Technology, 2020, 39(4): 9-15.

[14] WU F, FENG F, GOOI H B. Cooperative triple-phase- shift control for isolated DAB DC-DC converter to improve current characteristics[J]. IEEE Transactions on Industrial Electronics, 2019, 66(9): 7022-7031.

[15] 盧林煜, 王魯楊, 柏揚, 等. 面向能源互聯(lián)網(wǎng)的固態(tài)變壓器中雙有源橋直流變換器研究[J]. 電力系統(tǒng)保護與控制, 2019, 47(6): 141-150.

LU Linyu, WANG Luyang, BAI Yang, et al. Research on dual-active-bridge DC-DC converter in solid state transformer for energy internet[J]. Power System Protection and Control, 2019, 47(6): 141-150.

[16] 侯川川, 仇志麗, 劉建華. 雙有源橋輕載下的軟開關(guān)研究[J]. 電力系統(tǒng)保護與控制, 2017, 45(8): 23-29.

HOU Chuanchuan, QIU Zhili, LIU Jianhua. Research on soft switching of dual active bridge with light load[J]. Power System Protection and Control, 2017, 45(8): 23-29.

[17] YAN Y, GUI H, BAI H. Complete ZVS analysis in dual active bridge[J]. IEEE Transactions on Power Electronics, 2021, 36(2): 1247-1252.

[18] ZHAO B, SONG Q, LIU W. Efficiency characterization and optimization of isolated bidirectional DC/DC converter based on dual phase shift control for DC distribution application[J]. IEEE Transactions on Power Electronics, 2013, 28(4): 1711-1727.

[19] ZHAO Biao, SONG Qiang, LIU Wenhua. Current stress optimized switching strategy of isolated bidirectional DC-DC converter with dual phase shift control[J]. IEEE Transactions on Industrial Electronics, 2013, 60(10): 4458-4467.

[20] 高帥, 張興, 趙文廣, 等. 雙有源橋DC-DC變換器最小回流功率控制策略[J]. 電氣工程學(xué)報, 2019, 14(2): 24-29.

GAO Shuai, ZHANG Xing, ZHAO Wenguang, et al. Minimum reactive power control strategy for dual active bridge DC-DC converter[J]. Journal of Electrical Engineering, 2019, 14(2): 24-29.

[21] 胡燕, 張宇, 張?zhí)鞎? 等. 考慮不同軟開關(guān)模式的雙有源橋變換器電流應(yīng)力優(yōu)化方法[J]. 電力系統(tǒng)自動化, 2019, 43(23): 58-64.

HU Yan, ZHANG Yu, ZHANG Tianhui, et al. Optimization method of current stress for dual active bridge converter considering different soft switching mode[J]. Automation of Electric Power Systems, 2019, 43(23): 58-64.

[22] WANG P, CHEN X, TONG C, et al. Large and small signal average value modeling of dual active bridge DC-DC converter with triple-phase-shift control[J]. IEEE Transactions on Power Electronics, 2021, 36(8): 9237-9250.

[23] TANG Y, HU W, XIAO J, et al. Reinforcement learning based efficiency optimization scheme for the DAB DC-DC converter with triple phase shift modulation[J]. IEEE Transactions on Industrial Electronics, 2021, 68(8): 7350-7361.

[24] SONG W, HOU N, WU M. Virtual direct power control scheme of dual-active-bridge DC-DC converters for fast dynamic response[J]. IEEE Transactions on Power Electronics, 2018, 33(2): 1750-1759.

[25] LIU X, ZHU Z, STONE D A, et al. Novel dual-phase-shift control with bidirectional inner phase shifts for a dual active bridge converter having low surge current and stable power control[J]. IEEE Transactions on Power Electronics, 2017 32(5): 4095-4106.

[26] ZHAO B, SONG Q, LIU W. Power characterization of isolated bidirectional dual active bridge DC-DC converter with dual phase shift control[J]. IEEE Transactions on Power Electronics, 2012, 27(9): 4172-4176.

[27] 胡燕, 張?zhí)鞎? 楊立新, 等. 雙重移相DAB變換器回流功率優(yōu)化與電流應(yīng)力優(yōu)化的對比研究[J]. 中國電機工程學(xué)報, 2020, 40(增刊1): 243-253.

HU Yan, ZHANG Tianhui, YANG Lixin, et al. Comparative study of reactive power optimization and current stress optimization of dab converter with dual phase shift control[J]. Proceedings of the CSEE, 2020, 40(S1): 243-253.

[28] HOU N, SONG W, WU M. Minimum current stress scheme of dual active bridge DC-DC converter with unified phase-shift control[J]. IEEE Transactions on Power Electronics, 2016, 31(12): 8552-8561.

[29] HEBALA O M, ABOUSHADY A A, AHMED K H. Generic closed-loop controller for power regulation in dual active bridge DC-DC converter with current stress minimization[J]. IEEE Transactions on Industrial Electronics, 2019, 66(6): 4468-4478.

Dual phase shift modulation strategy for reactive power suppression of a DAB converter

LI Shanshou1, WANG Hao1, YE Wei2, FANG Qiansheng1, YAN Pu1

(1. Key Laboratory of Intelligent Building & Building Energy Saving, Anhui Jianzhu University, Hefei 230022, China; 2. Anhui Nari-Jiyuan Power Grid Technology Co., Ltd., Hefei 230088, China)

There is a problem in that reactive power is large in the medium and low power range when the voltage on two sides of the transformer is mismatched under the traditional dual phase shift (DPS) modulation of a dual active bridge (DAB) converter. Thus a dual phase shift (DPS-RPS) modulation strategy is proposed to suppress the reactive power. First, the working principle of DPS-RPS modulation strategy is analyzed and a mathematical model is established. Based on the model, the current stress is optimized. Then the reactive power and current stress of DPS and DPS-RPS modulation are compared for when the current stress is at a minimum. The results show that compared with DPS modulation, DPS-RPS modulation not only decreases the reactive power, but also reduces the current stress in the medium and low power range. Finally, the feasibility and effectiveness of the proposed DPS-RPS modulation are verified by experiment.

dual active bridge converter; dual phase shift; reactive power; current stress

10.19783/j.cnki.pspc.211503

國家自然科學(xué)基金項目資助(61901006)；博士科研啟動項目資助(2020QDZ40)

This work is supported by the National Natural Science Foundation of China (No. 61901006).

2021-11-05；

2022-04-06

李善壽(1979—)，男，博士，副教授，研究方向為新能源發(fā)電及電力電子變換技術(shù)。E-mail: xlisq79@163.com

(編輯 周金梅)