Switching Circuit Designing for High-Power Synchronous Buck Converters: An Experimental Approach

Mazdak Ebadi ¹ (Department of Electrical Engineering- Arak University, Arak, Iran)
Mohammad Amin Bahramian ² (Department of Electrical Engineering- Arak University, Arak, Iran)
Ali Asghar Ghadimi ³ (Department of Electrical Engineering- Arak University, Arak, Iran)

Submited date : 2023-05-08 accepted date : 2023-08-19

Keywords: Buck converter, Dead-time control, Soft Start-up, High-power,

Abstract :

Non-isolated buck converters are well-known solutions for producing controllable DC voltage at medium and high-power levels. Meanwhile, synchronous converters have received a lot of attention due to the non-dependence of the voltage conversion ratio on the load and the continuity of the inductor current. But the switching of these converters takes place at higher power levels at lower frequencies. For this reason, the switching circuit must work with a higher dead time. In this article, an analog application circuit design without the use of a microcontroller is presented for the switching of the synchronous buck converter, which, while ensuring that pulses are not sent to the keys at the same time, the amount of dead time can be It provides a setting that can be changed according to the voltage level and current of the circuit. After analyzing the conditions at the moment of switching on and off of the circuit, it was found that at the moment of switching off, a destructive transient current is applied to the keys, which this article solves this issue by using two fast SSR relays in the path of the input signal to the gate module. The driver suggests that it has been tested on a prototype device. This article also mentions the requirements of the switching circuit by analyzing the conditions of the moment when the circuit is turned on and off, so that the transient damaging current does not pass through the IGBT. The results of experimental tests on a 15 kW synchronous buck DC/DC converter with an output of 300 V 50 amps show that the well-designed switching circuit creates an adjustable dead time of up to 6 microseconds in the switching of this converter and the continuity conditions It has provided the inductor current both in no load and under load. Also, the proposed method has well removed the transients of the circuit turning on and off.

References:

[1] K. Yari, S.H. Shahalami, H. Mojallali, "High step-up isolated dc–dc converter with single input and double output and soft‐switching performance for renewable energy applications", IET Power Electronics, vol. 12, no. 11, pp. 2942-2952, Sept. 2019 (doi: 10.1049/iet-pel.2019.0450).

[2] L. Mei, D. Williams, W. Eberle, "A synchronous buck converter using a new predictive analog dead-time control circuit to improve efficiency", Canadian Journal of Electrical and Computer Engineering, vol. 36, no. 4, pp. 181-187, Fall 2013 (doi: 10.1109/CJECE.2014.2303521).

[3] C.J. Chen, P.Y. Wang, S.T. Li, Y.M. Chen, Y.C. Chang, "An integrated driver with bang-bang dead-time control and charge sharing bootstrap circuit for gan synchronous buck converter", IEEE Trans. on Power Electronics, vol. 37, no. 8, pp. 9503-9514, Mar. 2022 (doi: 10.1109/TPEL.2022.3159717).

[4] C.-J. Chen, P.-K. Chiu, Y.-M. Chen, P.-Y. Wang, Y.-C. Chang, "An integrated driver with adaptive dead-time control for gan-based synchronous buck converter", IEEE Trans. on Circuits and Systems II: Express Briefs, vol. 69, no. 2, pp. 539-543, Jul. 2021 (doi: 10.1109/TCSII.2021.3098310).

[5] M. Asad, A.K. Singha, and R.M.S. Rao, "Dead time optimization in a GaN-based buck converter", IEEE Trans. Power Electron., vol. 37, no. 3, pp. 2830-2844, Sep. 2021 (doi: 10.1109/TPEL.2021.3116126).

[6] A. N. Hopkins, P. Proynov, N. McNeill, B. H. Stark, P. H. Mellor, "Achieving efficiencies exceeding 99% in a super-junction 5-kW DC-DC converter power stage through the use of an energy recovery snubber and dead-time optimization", IEEE Trans. on Power Electronics, vol. 33, no. 9, pp. 7510-7520, Nov. 2017 (doi: 10.1109/TPEL.2017.2773459).

[7] Z. Peiravan, M. Delshad, M. Amini, "A new soft switching interleaved flyback converter with recovery leakage inductance energy", Journal of Intelligent Procedures in Electrical Technology, vol. 13, no. 50, pp.31-47, Sept. 2022 (dor: 20.1001.1.23223871.1401.13.50.2.3).

[8] M. Mirtalaei, M. Mohtaj, H.R. Karami, "Design and implementation of a high step-up boost-sepic hybrid converter with soft switching", Journal of Intelligent Procedures in Electrical Technology, vol. 6, no. 24, pp. 27-34, Mar. 2016 (dor: 20.1001.1.23223871.1394.6.24.3.3).

[9] S. Shabani, M. Delshad, R. Sadeghi, "A soft switched non-isolated high step-up dc-dc converter with low number of auxiliary elements", Journal of Intelligent Procedures in Electrical Technology, vol. 13, no. 51, pp. 123-136, Oct. 2022 (dor: 20.1001.1.23223871.1401.13.51.8.1).

[10] C. Wu, W.L. Goh, C.L. Kok, L. Siek, Y.H. Lam, X. Zhu, R.P. Singh, "Asymmetrical dead-time control driver for buck regulator", IEEE Trans. on Very Large Scale Integration (VLSI) Systems, vol. 24, no. 12, pp. 3543-3547, April 2016 (doi: 10.1109/TVLSI.2016.2551321).

[11] Q. Yan, X. Yuan, "A double-modulation-wave PWM for dead-time-effect elimination and synchronous rectification in SiC-device-based high-switching-frequency converters", IEEE Trans. on Power Electronics, vol. 35, no. 12, pp. 13500-13513, April 2020 (doi: 10.1109/TPEL.2020.2991583).

[12] B. Li, J. Xu, J. Ye, H. Wang, S. Huang, Y. Li, A. Shen, "A New Model-Based Dead-Time Compensation Strategy for Cascaded H-Bridge Converters", IEEE Trans. on Industrial Electronics, vol. 70, no. 4, pp. 3793-3802, June 2022 (doi: 10.1109/TIE.2022.3177757).

[13] Y. Zhang, C. Chen, Y. Xie, T. Liu, Y. Kang, H. Peng, "A high-efficiency dynamic inverter dead-time adjustment method based on an improved GaN HEMTs switching model", IEEE Trans. on Power Electronics, vol. 37, no. 3, pp. 2667-2683, Sep. 2021 (doi: 10.1109/TPEL.2021.3112694).

[14] N. Narasimman, R. Salahuddin, R.P. Singh, "An 86% efficiency multi-phase buck converter using time-domain compensator and adaptive dead-time control for DVS application", Proceeding of the IEEE/IECON, pp. 2255-2260, Singapore, Oct. 2020 (doi: 10.1109/IECON43393.2020.9255080).

[15] D. Sha, Y. Zhao, D. Zhang, "ZVS-interleaved synchronous buck DC–DC converter with a coupled inductor by varying switching frequency and deadtime", IEEE Trans. on Power Electronics, vol. 37, no. 7, pp. 8190-8198, Jan. 2022 (doi: 10.1109/TPEL.2022.3141253).

[16] L. Zhang, L. Ren, S. Bai, S. Sang, J. Huang, X. Zhang, "Self-adaption dead-time setting for the SiC MOSFET boost circuit in the synchronous working mode", IEEE Access, vol. 10, pp. 57718-57735, May 2022 (doi: 10.1109/ACCESS.2022.3179403).

[17] J. Wittmann, A. Barner, T. Rosahl, B. Wicht, "An 18 V input 10 MHz buck converter with 125 ps mixed-signal dead time control", IEEE Journal of Solid-State Circuits, vol. 51, no. 7, pp. 1705-1715, May 2016 ( doi: 10.1109/JSSC.2016.2550498).

[18] J. Tang, T. Guo, J. S. Kim, J. Roh, "A current-mode four-phase synchronous buck converter with dynamic dead-time control", IEEE Access, vol. 9, pp. 81078-81088, June 2021 (doi: 10.1109/ACCESS.2021.3085826).

[19] D. Luo, Y. Gao, P.K. Mok, "A gan driver for a bi-directional buck/boost converter with three-level v gs protection and optimal-point tracking dead-time control", IEEE Trans. on Circuits and Systems, vol. 69, no. 5, pp. 2212-2224, Feb. 2022 (doi: 10.1109/TCSI.2022.3146190).

[20] Z. Sun, K.W.R. Chew, H. Tang, L. Siek, "Adaptive gate switching control for discontinuous conduction mode DC–DC converter", IEEE Trans. on Power Electronics, vol. 29, no. 3, pp. 1311-1320, May 2013 (doi: 10.1109/TPEL.2013.2263579).

[21] Z. Zhang, H. Lu, D. J. Costinett, F. Wang, L.M. Tolbert, B.J. Blalock, "Model-based dead time optimization for voltage-source converters utilizing silicon carbide semiconductors", IEEE Trans. on Power Electronics, vol. 32, no. 11, pp. 8833-8844, Dec. 2016 (doi: 10.1109/TPEL.2016.2645578 ).

[22] Y. Zhang, W. Xu, Y. Xie, T. Liu, Z. Wu, C. Chen, Y. Kang, H. Peng, "Analysis of dead-time energy loss in GaN-based TCM converters with an improved GaN HEMT model", IEEE Trans. on Power Electronics, vol. 38, no. 2, pp. 1806-1818, Oct. 2022 (doi: 10.1109/TPEL.2022.3217456).

[23] C.H. Tsai, C.H. Yang, J.H. Shiau, B.T. Yeh, "Digitally controlled switching converter with automatic multimode switching", IEEE Trans. on Power Electronics, vol. 29, no. 4, pp. 1830-1839, May 2013 (doi: 10.1109/TPEL.2013.2265297).

[24] L. Wang, Q. Zhu, W. Yu, A.Q. Huang, "A medium-voltage medium-frequency isolated DC–DC converter based on 15-kV SiC MOSFETs", IEEE Journal of Emerging and Selected Topics in Power Electronics, vol. 5, no. 1, pp. 100-109, Dec. 2016 (doi: 10.1109/JESTPE.2016.2639381).

[25] Z. Yao S. Lu, "A simple approach to enhance the effectiveness of passive currents balancing in an interleaved multiphase bidirectional DC–DC converter", IEEE Trans. on Power Electronics, vol. 34, no. 8, pp. 7242-7255, Nov. 2018 (doi: 10.1109/TPEL.2018.2881058).

[26] J. Zhang, J.S. Lai, R.Y. Kim, W. Yu, "High-power density design of a soft-switching high-power bidirectional dc–dc converter", IEEE Trans. on power electronics, vol. 22, no. 4, pp. 1145-1153, July 2007 (doi: 10.1109/TPEL.2007.900462).

[27] J. Hu, Z. Yang, S. Cui, R.W. Doncker, "Closed-form asymmetrical duty-cycle control to extend the soft-switching range of three-phase dual-active-bridge converters", IEEE Trans. on Power Electronics, vol. 36, no. 8, pp. 9609-9622, Jan. 2021 (doi: 10.1109/TPEL.2021.3055369).

[28] D. Liu, F. Deng, Z. Chen, "Five-level active-neutral-point-clamped DC/DC converter for medium-voltage DC grids", IEEE Trans. on Power Electronics, vol. 32, no. 5, pp. 3402-3412, June 2016 (doi: 10.110­9/TP­EL.2­016.2585618).