Abstract：In order to improve the power supply efficiency to power amplifier in 3G communication system, an envelope tracking power supply, consists of a multilevel converter in series connected with a linear power supply, is proposed. This scheme can operate the switches in same frequency with the reference signal, so as to gain better tracking bandwidth compared to existing general schemes. In basic control method for envelop tracking power supply, the closed loop can not suppress the disturbance effectively. To address the problem, the feed-forwarding the step-wave voltage control strategy is proposed. For practical implementation, the thesis proposes the frequency compensation scheme of cascaded operational amplifiers to extend the equivalent bandwidth; and the high-frequency spike suppression scheme to match the transfer functions of the two branches between step-wave voltage and output port, so as to eliminate the disturbance effect to the output voltage. A prototype for 300kHz sine wave tracking, with 10～32V output voltage and 50W peak output power is built. The experimental results validate the schemes proposed.
郗焕, 金茜, 阮新波. 考虑运算放大器带宽限制包络线跟踪电源的前馈控制策略[J]. 电工技术学报, 2014, 29(4): 142-151.
Xi Huan, Jin Qian, Ruan Xinbo. Feed-Forward Control Strategy for Envelope Tracking Power Supply Considering Bandwidth Limitation of Operational Amplifiers. Transactions of China Electrotechnical Society, 2014, 29(4): 142-151.
[1] Nujira energy primer[W]. http://www.nujira.com. [2] Staudinger J, Gilsdorf B, Newman D, et al. High efficiency CDMA RF power amplifier using dynamic envelope tracking technique[C]. IEEE MTT-S Digest, 2000: 873-876. [3] Nujira whitepaper. Driving down operator OPEX-the crucial contribution of ultra-high efficiency RF power amplifiers[W]. http://www.nujira.com. [4] Hanington G, Chen P, Asbeck P M, et al. High-efficiency power amplifier using dynamic power-supply voltage for CDMA applications[J]. IEEE Transactions on Microwave Theory and Techniques, 1999, 47(8): 1471-1476. [5] Yousefzadeh V, Wang N, Maksimović D, et al. Digitally controlled DC-DC converter for RF power amplifier[C]. Proceading of. IEEE Applied Power Electronics Conference, 2004: 81-87. [6] Soto A, Oliver J A, Cobos J A, et al. Power supply for a radio transmitter with modulated supply voltage[C]. Proceedings of IEEE Applied Power Electronics Conference, 2004: 392-398. [7] Yousefzadeh V, Alarcón E, Maksimović D. Three-level buck converter for envelope tracking applications[J]. IEEE Transactions on Power Electronics, 2006, 21(2): 549-552. [8] Høyerby M C W, Andersen M A E. Envelope tracking power supply with fully controlled 4th order output filter[C]. Proceedings of IEEE Applied Power Electronics Conference, 2006: 993-1000. [9] Yundt G B. Series parallel connected composite amplifiers[D]. Master Thesis. Massachusetts Institute of Technology, 1983. [10] Ertl H, Kolar J W, Zach F C. Basic considerations and topologies of switched-mode assisted linear power amplifiers[J]. IEEE Transactions on Industrial Electronics, 1997, 44(1): 116-123. [11] Vander Zee R A R, Van Tuijl A J M. A power-efficient audio amplifier combining switching and linear techniques[J]. IEEE Journal of Solid-State Circuits, 1999, 34(7): 985-991. [12] Midya P. Linear switcher combination with novel feedback[C]. Proceedings of IEEE Power Electronics Specialist Conference, 2000: 1425-1429. [13] Høyerby M C W, Andersen M A E. High-bandwidth, high-efficiency envelope tracking power supply for 40W RF power amplifier using paralleled bandpass current sources[C]. Proceedsings of IEEE Power Electronics Specialist Conference, 2005: 2804-2809. [14] Rivas J M, Wahby R S, Shafran J S, et al. New architectures for radio-frequency DC-DC power conversion[J]. IEEE Transactions on Power Electronics, 2006, 21(2): 380-393. [15] Sahu B, Rincón Mora G A. A high-efficiency linear RF power amplifier with a power-tracking dynamically adaptive buck-boost supply[J]. IEEE Transactions on Microwave Theory and Techniques, 2004, 52(1): 112-120. [16] Hudspeth T, Kaplan D S, Rosen H A. Envelope amplifier: US, 4831334[P]. 1989-05-16. [17] Myers R G, Buer K V, Raab F H. Method and apparatus for high efficiency high dynamic range power amplification: US, 5929702[P]. 1999-07-27. [18] Shvarts E Y, Triolo A A, Ziesse N G. Variable output power supply: US 2013/0146791A1[P]. 2003-08-07. [19] Wilson M P. High efficiency amplification: US 2006/0028271A1[P]. 2006-02-09. [20] Wilson M P. Transformer based voltage supply: US, 2007/0279019A1[P]. 2007-12-06. [21] Hambley A R. Electronics[M]. 2nd ed. New Jersey: Prentice- Hall, Income, 2000. [22] Ron M. Op amps for everyone[R]. TI Design Reference SLOD006B, Texas Instruments, 2002. [23] OPA3690 datasheet[W]. http://www.ti.com.
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