Received: 3 March 2019 Revised: 11 May 2019 Accepted: 25 June 2019 DOI: 10.1002/2050-7038.12141 RESEARCH ARTICLE Multicell multi-output converter to counter unbalanced input sources in nanogrid applications Naresh K. Pilli Saif Ali Khan Avneet Kumar Santosh K. Singh Department of Electrical Engineering, Indian Institute of Technology (BHU) Varanasi, Varanasi, Uttar Pradesh, India Correspondence Naresh K. Pilli, Varanasi, Uttar Pradesh 221005, India. Email: pnkumar.rs.eee13@iitbhu.ac.in Summary Nanogrid is an apt solution to encourage renewable power generation and counter the problem of global warming. It comprises of mostly the PV sources feeding both AC and DC loads. To meet out this scenario, a converter that can convert DC to both DC and AC is required. This paper proposes a hybrid con- verter providing both AC and DC output for DC input. The proposed converter is a derived form of Split-Pi converter, known as hybrid Split-Pi. It works in both boost and buck mode. Inherent shoot through problem of bridge circuit present in a Split-Pi converter is eliminated as the shoot-through period is utilized to charge the boost inductor of the proposed converter. Hence, enhanced output is obtained because of the absence of dead time operation. A hardware prototype is developed to validate the proposed converter. Proposed converter is tested for both buck and boost mode. Variation of AC and DC gain with change in duty ratio is observed. The output AC RMS and its THD is studied for different mod- ulation index. Peak of output AC voltage is limited by the input DC voltage. To overcome this issue, the single cell proposed converter is extended to a multi- cell arrangement. Multicell arrangement integrates multiple input DC voltage sources having different voltage levels. It is simulated for different cases and outputs are discussed. KEYWORDS DC, power electronics applications 1 INTRODUCTION Global warming, a serious concern for world community enforces many countries to cut down the green house gas emis- sion and motivates to go for green energy by the use of renewable energy sources for power generation. Distributed generation from renewable sources not only encourages the green energy but also minimizes the transmission loss of power being transferred from remote location where power is generated through conventional methods. 1,2 Nanogrid is a power system architecture, where power generated through renewable sources are connected to the grid locally through power electronic converters. 3-7 Schematic of DC nanogrid where power is supplied primarily by PV panels is shown in Figure 1. It comprises of PV panel, battery bank, and various DC and AC loads. To supply power to both DC and AC loads, a DC-DC converter and Abbreviations: ESR, Equivalent series resistance; P, Power mode; PV, Photovoltaic; PWM, Pulse width modulation; SPWM, Sinusoidal pulse width modulation; ST, Shoot through mode; THD, Total harmonic distortion; Z, Zero mode; ZSI, Z source inverter. Int Trans Electr Energ Syst. 2019;e12141. wileyonlinelibrary.com/journal/etep © 2019 John Wiley & Sons, Ltd. 1 of 16 https://doi.org/10.1002/2050-7038.12141