THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. 2017 Apr.; 28(4), 298308. http://dx.doi.org/10.5515/kjkiees.2017.28.4.298 ISSN 1226-3133 (Print)ISSN 2288-226X (Online) Reduction of Conducted Emission in Interleaved RPWM Buck Converter 이승현 이근봉 나완수 Seunghyun LeeKeunbong Lee*Wansoo Nah 요약 DC-DC Converter Random PWM Interleaved Buck Converter(IBC). PWM EMI. PRBS IBC. 2 180 2 PWM. IBC 1,,,,. PSIM Random PWM IBC PWM RPWM Buck-converter PSIM. Abstract This paper presents a Interleaved Buck Converter(IBC) system with Random PWM to reduce electromagnetic noise by harmonics. Swithced mode power supply generally controlled by high switching frequency have a electromagnetic interference(emi) issue due to the high-voltage/high-current switching to regulate the voltage in buck converter. To solve the problem. we present a novel IBC system with PRBS. IBC system has two active switches with 180 phase difference that controll the cicuit with two PWM signal. IBC system may be disadventageous for the cost due to the addtion of one set of switch, but it has adventages of power distribution, current ripple cancellation, fast transient response, and passive component size reduction. To verify the validity of study, simulation program has been bulit using PSIM and the experimental results of IBC system using RPWM was compared with the conventinal PWM and randomized PWM. Key words: DC/DC Converter, Interleaved Buck Converter(IBC), Random PWM(RPWM), PRBS, Harmonics. 서론, EMC(Electro-Magnetic Compatibility)., IoT,. 2016()(No. 2016R1A2B4015020). (Departmemt of Electrical and Computer Engineering, Sungkyunkwan University) *SK (SK Hynix) Manuscript received February 14, 2017 ; Revised March 8, 2017 ; Accepted April 11, 2017. (ID No. 20170214-011) Corresponding Author: Wansoo Nah (e-mail: wsnah@skku.edu) 298 c Copyright The Korean Institute of Electromagnetic Engineering and Science. All Rights Reserved.
, EMI(Electro-Magnetic Interference). Switching Mode Power Supply(SMPS)., SMPS DC-DC. DC-DC PWM, RF system., SMPS ESL(Equivalent Series Inductance) ESR(Equivalent Series Resistance), EMC [1]. EMI RPWM(Random Pulse Width Modulation) [2],[3]. RPWM. EMI,., Buck Interleaved Buck Converter(IBC) [4]. 180 2 PWM,,,,. 50 % 6 V, 3 V Buck PWM, RPWM, IBC with RPWM PSIM. (ATmega 128 Pro-a),,.. 기존 Buck 컨버터의동작특성 Buck DC-DC.,.,.. (1) D, 1 6 V D 0.5 3 V 1. 2-1 기존 PWM 제어방식 PWM(Pulse Width Modulation) 2. (Comparater),., PWM. PWM, 그림 1. 3 Buck, Fig. 1. Input, output voltage of Buck converter using the circuit in Fig. 3 (1) 299
THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 28, no. 4, Apr. 2017. 그림 4. PWM Fig. 4. Generate PWM signal for feedback control. 그림 2. PWM Fig. 2. Principle of operating PWM method using periodic triangular waveform.. EMI,. EMC. 2-2 기존의 PWM 을이용한 Buck 컨버터설계및 제작 3 PWM Buck. 6 V, 50 % 3 V, 1.66 khz., 50 %. MOSFET, 그림 5. PRBS RPWM Fig. 5. Generate RPWM signal by PRBS., PWM. 4 1.66 khz PWM MOSFET,. 6 PSIM 9.0 MOSFET, 1.66 khz 그림 3. PWM Buck Fig. 3. Converntional PWM Buck converter scheme. 그림 6. PWM Fig. 6. Simulation result of current harmonics in PWM. 300
. 2-3 RPWM 제어방식 Random PWM(RPWM) PWM,. 7 PWM RPWM. PWM RPWM,. RPWM HSF(Harmonic Spread Factor), [5]. (a) (2) (2), (3) j, N. HSF PWM,. 7. 7 (b) [6]. 2-4 RPWM 제어방식을이용한 Buck 컨버터설계및제작 8. PRBS(Peseudo Random Bit Sequence) (shift register) (EXCLUSIVE OR gate) [7]. lead-lag, m-bits 8,.. m-bits (3) (b) 그림 7. (a) PWM, (b) RPWM Fig. 7. (a) Conventional PWM harmonics, (b) RPWM harmonics state. K-clock. PRBS,. PRBS (4). PRBS (8, 10). (4), i., (Multiplxer) 8 Pseudo random frequency carrier. 8 C, 2 1.. R C P. P R 301
THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 28, no. 4, Apr. 2017. 그림 8. Pseuedo random carrier Fig. 8. Basic principle of the pseudo random carrier generation circuit.. P 0 R, P 1 C. R, PSIM. 9 1 1, 0 1 (Offset). 9 4,.., (6) (5) (6) Ω Ω 을대입하면 그림 9. Fig. 9. Offset circuit for generating digital random triangle waveform. Ω Ω Ω 삼각파 삼각파 Ω Ω Ω 삼각파 (7), 0.5. 1 1 0.5 0.5, DC 0.5 V 0 1, 9. 10 RPWM Buck. PWM Buck, PWM. 50 % 6 V, 3 V, 1.66 khz. PRBS 1 V 8, 11 0 1. 180. PRBS High Low 12. 302
그림 10. RPWM Buck Fig. 10. RPWM Buck converter scheme. 그림 13. RPWM Fig. 13. Simulation result of current harmonics in RPWM.,. 2-5 제안하는인터리브드 RPWM Buck 컨버터구조 그림 11. Peseudo Random Bit Sequence(PRBS) Fig. 11. Simulation result of Peseudo Random Bit Sequence (PRBS). RPWM. 13 RPWM, 14 Buck. Buck,,, PWM. 15 그림 12. PRBS Fig. 12. Output of random triangular waveform by PRBS state. 그림 14. RPWM Buck Fig. 14. Block diagram for the proposed interleaved RPWM Buck converter scheme. 303
THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 28, no. 4, Apr. 2017. 그림 15. RPWM Fig. 15. Digital control block diagram of interleaved RP- WM Buck converter...,., 180.,,. 2-6 인터리브드 RPWM 제어방식을이용한 Buck 컨 버터설계및제작, Buck 10 RPWM Buck, 14. 2, 15., 16.. 실험및고찰 RPWM DC/DC Buck. 1.66 khz, 17. (LPF) L=100 uh, C=2,200 uf, R=10 W, 10 Ω, MOSFET., PWM. 18 180 그림 16. Interleaved RPWM Buck Fig. 16. Current harmonics in Interleave RPWM Buck converter at power line. 그림 17. Buck Fig. 17. Buck converter in experiment. 304
20. 20 그림 18. Op-amp, Fig. 18. Non-inverting, inverting triangular waveform with opamp. 11 PRBS 19. PRBS 8,, Keysight 33522b. PR- BS High, Low 19,, 15 ATmega 128 pro-a. PWM, Buck.. (a) PWM (b) RPWM (c) Interleaved RPWM 그림 19. Fig. 19. Experimental result of random triangular waveform. 그림 20. Fig. 20. Current waveform in time domain. 305
THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 28, no. 4, Apr. 2017. (a), 20(b). 20(a). 20(c) (a) (b). 20(a) 0.6 ms, (b), (c).. 21 (a) 1.66 khz. 20(a) 0.6 ms =1.66 khz. (b),, 20(b). 20(b) 273 us =3,663 Hz, 21(b)., 1.239 ms =800 Hz,,. (a). 6,,. (c), 20(c), (a) (b)., 180, (a) PWM (b) RPWM (c) Interleaved RPWM 그림 21. Fig. 21. Current harmonics in frequency domain.. 306
. PWM RPWM,. References 그림 22. Fig. 22. Comparison current harmonics in frequency domain by log scale. 19 y,.,.. 결론 DC-DC Random PWM Buck. Pseudo random bit sequence(prbs) PRBS, Buck RPWM.,. Buck, 180,, [1] Henry W. Ott, Electromagnetic Compatibility Engineering, John Wiley & Sons, pp. 172-184, 2009. [2] K. K. Tse, Henry Shu-hung Chung, "A comparative investigation on the use of random modulation schemes for DC/DC converters", IEEE Transaction on Industrial Electronics, vol. 47, no. 2, pp. 253-263, Apr. 2000. [3] Ki-Seon Kim, Young-Gook Jung, and Young-Cheol Lim, "A new hybrid random PWM scheme", IEEE Transaction on Power Electronics, vol. 24, no. 1, pp. 192-200, Jan. 2009. [4] Morteza Esteki, Behzad Poorali, Ehsan Adib, and Hosein Farzanehfard, "Interleaved buck converter with continuous input current, extremely low output current ripple, low switching losses, and improved step-down conversion ratio", IEEE Transaction on Industrial Elctronics, vol. 62, no. 8, pp. 4769-4776, Aug. 2015. [5] V. Krishnakumar, V. Kamaraj, and S. Jeevananthan, "Random pulse width modulation for performance improvement of brushless DC motor drive", IEEE Transaction on Electrical Energy Systems, pp. 157-163, Jan. 2014. [6] Yen-Shin Lai, "Novel random-switching PWM Technique with constant sampling frequency and constant inductor average current for digitally controlled converter", IEEE Transaction on Industrial Electronics, vol. 60, no. 8, pp. 3126-3135, Aug.2013. [7] Young-Cheol Lim, Seog-Oh Wi, Jong-Nam Kim, and Young-Gook Jung, "A pseudorandom carrier modulation scheme", IEEE Transaction on Power Electronics, vol. 25, no. 4, pp. 797-805, Apr. 2010. 307
THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 28, no. 4, Apr. 2017. 2014 8: () 2014 9: [ 주관심분야 ] EMI/EMC, Filter Design 1984 2: ( ) 1986 2: ( ) 1991 2: ( ) 19911993: SSCL Guest Collaborator 19931995: 1995: [ 주관심분야 ] Signal Integrity, Power Integrity, EMI/EMC 2014 2: ( ) 2016 2: () 2016 3: SK [ 주관심분야 ] EMI/ EMC, Filter Design 308