Journal of Advanced Navigation Technology (한국항행학회논문지)

The Korean Navigation Institute (한국항행학회)
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Performance Analysis of 6.78MHz Current Mode Class D Power Amplifier According to Load Impedance Variation

부하 임피던스 변화에 따른 6.78MHz 전류모드 D급 전력증폭기 특성 해석

  • Go, Seok-Hyeon (Dept. of Electronics Engineering, Incheon National University) ;
  • Park, Dae-kil (Dept. of Electronics Engineering, Incheon National University) ;
  • Koo, Kyung-Heon (Dept. of Electronics Engineering, Incheon National University)
  • Received : 2019.02.21
  • Accepted : 2019.04.23
  • Published : 2019.04.30
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Abstract

This paper has designed a current mode class D power amplifier to increase the transmission efficiency of a 6.78 MHz wireless power transfer (WPT) transmitter and to ensure stable characteristics even when the transmitting and receiving coil intervals change. By reducing the loss due to the parasitic capacitor component of the transistor, which limits the theoretical efficiency of the linear amplifier, this research has improved the efficiency of the power amplifier. The circuit design simulator was used to design the high efficiency amplifier, and the power output and efficiency characteristics according to the load impedance change have been simulated and verified. In the simulation, 42.1 dBm output and 95% efficiency was designed at DC bias 30 V. The power amplifier was fabricated and showed 91% efficiency at the output of 42.1 dBm (16 W). The transmitting and receiving coils were fabricated for wireless power transfer of the drone, and the maximum power added efficiency was 88% and the output power was $42.1dBm{\pm}1.7dB$ according to the load change causing from the coil intervals.

본 논문은 6.78 MHz무선전력전송 송신기의 전송 효율을 높이고 송수신 코일 간격 변화에도 안정적 특성을 확보하기 위해 전류 모드 클래스 D 전력증폭기를 설계한다. 선형증폭기의 이론적인 효율을 제한하는 트랜지스터의 기생 커패시터 성분에 의한 손실을 적게 만들어 전력증폭기의 효율을 향상시킨다. 회로 설계 시뮬레이터를 이용하여 고효율 증폭기를 설계하고 부하 임피던스 변화에 따른 전력 출력, 효율 특성을 시뮬레이션하여 검증하였다. 시뮬레이션에서 DC 바이어스 30 V일 때 42.1 dBm의 출력과 95%의 효율을 갖도록 설계하였다. 전력증폭기를 제작하여 42.1 dBm (16 W)의 출력에서 91%의 효율을 보였다. 드론 무선전력전송에 적용될 송수신 코일을 제작하였으며, 송수신 코일 간격에 따른 부하변화에 따라 전력부가효율이 최대 88% 이고 출력전력 $42.1dBm{\pm}1.7dB$의 특성을 나타내었다.

Keywords

HHHHBI_2019_v23n2_166_f0001.png 이미지

그림 1. Voltage mode class D 전력증폭기 회로 Fig. 1. Voltage mode class D power amplifier circuit.

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그림 2. Current mode class D 전력증폭기의 회로 Fig. 2. Current mode class D power amplifier circuit

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그림 3. 설계된 16 W급 전류모드 D급 전력증폭기 회로도 Fig. 3. A schematic diagram of the 16 watt CMCD power amplifier.

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그림 4. 입력전력에 따른 PAE, Pout 시뮬레이션 Fig. 4. PAE and Pout simulation according to input power

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그림 5. FET1 드레인 전압과 전류의 파형 시뮬레이션 Fig. 5. Simulated waveform of FET1 drain voltage and current.

HHHHBI_2019_v23n2_166_f0006.png 이미지

그림 6. 로드 임피던스 변화에 따른 전력부가효율 및 출력전력 Fig. 6. Power added efficiency and output power due to load impedance change.

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그림 7. 제작된 16 W 전류 모드 D급 전력증폭기 Fig. 7. Implemented 16 watt CMCD power amplifier.

HHHHBI_2019_v23n2_166_f0008.png 이미지

그림 8. 입력전력에 따른 PAE, Pout 측정값 Fig. 8. PAE and Pout measurement according to input power.

HHHHBI_2019_v23n2_166_f0009.png 이미지

그림 10. Rload 변화에 따른 PAE, 출력 전력 Fig. 10. PAE, load variation with output power.

그림 9. 제작된 60x80 mm2 송신 및 수신 코일 Fig. 9. Manufactured 60x80 mm2 transmit and receive coils.

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표 1. 송수신 코일 20 mm간격에서의 x축 변화량에 따른 S11 Table 1. S11 according to x-axis variation with 20mm separation of Tx and Rx coils.

HHHHBI_2019_v23n2_166_t0002.png 이미지

표 2. 송수신 코일 20 mm간격에서의 y축 변화량에 따른 S11 Table 2. S11 according to y-axis variation with 20mm separation of Tx and Rx coils.

HHHHBI_2019_v23n2_166_t0003.png 이미지

References

  1. J. Walker, Handbook of RF and microwave power amplifiers, 1-st ed. Cambridge, UK: Cambridge University Press, 2011.
  2. P. Srimuang, N. Puangngernmak, and S. Chalermwisutkul, "13.56 MHz class E power amplifier with 94.6% efficiency and 31 watts output power for RF heating applications," in 2014 11th International Conference on Electrical Engineering/Electronics, Computer, Telecommunications and Information Technology, Nakhon Ratchasima: Thailand, pp. 1-5, 2014.
  3. T. P. Hung,"Design of high-efficiency current-mode class-D amplifiers for wireless handsets," IEEE Transactions on Microwave Theory and Techniques, Vol. 53, No. 1, pp. 144-151, Jan. 2005. https://doi.org/10.1109/TMTT.2004.839327
  4. H. Kobayahshi, J. M. Hinrichis, and P. M. Asbeck,"Currentmode class D RF power amplifier for high efficiency RF application," IEEE Transaction Microwave Theory and Techniques, Vol. 49, No. 2, pp. 2480-2485, Dec. 2001. https://doi.org/10.1109/22.971639
  5. E. l. Hamamsy,"Design of high-efficiency RF class-D power amplifier," IEEE Transactions on Power Electronics, Vol. 9, No. 3, pp. 297-308, May. 1994. https://doi.org/10.1109/63.311263
  6. J. U. Mohammed and Z. R. Syed, "Performance analysis of high frequency BJT and LDMOS current mode class-D power amplifier," International Journal of Scientific & Engineering Research, Vol. 4, No 6, Jun. 2013. https://doi.org/10.14299/ijser.2013.06.001
  7. P. J. Gomez, "Analysis and design procedure of transmission-line transformers," IEEE Transaction Microwave Theory an d Techniques, Vol. 56, No. 1, pp. 163-171, Jan. 2008. https://doi.org/10.1109/TMTT.2007.912246
  8. M. C. Seo, J. B. Jeon, I. H. Jung, and Y. G. Yang, "Design of high-efficiency current mode class-D power amplifier using a transmission-line transformer and harmonic filter at 13.56MHz," The Journal of Korean Institute of Electromagnetic Engineering and Science, Vol. 23, No. 5, pp. 624-631, May. 2012. https://doi.org/10.5515/KJKIEES.2012.23.5.624
  9. D. Rooij and A. Michael, "The ZVS voltage-mode class-Damplifier, an $eGaN^{(R)}$ FET-enabled topology for highly resonant wireless energy transfer," in 2015 IEEE Applied Power Electronics Conference and Exposition (APEC), Charlotte: NC, pp. 1608-1613, 2015.
  10. C. Wang and Z. Ma, "Design of wireless power transfer device for UAV," in 2016 IEEE International Conference on Mechatronics and Automation, Harbin: China, pp. 2449-2454, 2016.