J Electr Eng Technol Vol. 9, No. 5: 1537-1543, 2014 http://dx.doi.org/10.5370/JEET.2014.9.5.1537 1537 Single Input Multi Output DC/DC Converter: An Approach to Voltage Balancing in Multilevel Inverter M. R. Banaei † , B. Nayeri* and E. Salary* Abstract – This paper presents a new DC/AC multilevel converter. This configuration uses single DC sources. The proposed converter has two stages. The first stage is a DC/DC converter that can produce several DC-links in the output. The DC/DC converter is one type of boost converter and uses single inductor. The second stage is a multilevel inverter with several capacitor links. In this paper, one single input multi output DC-DC converter is used in order to voltage balancing on multilevel converter. In addition, as compare to traditional multilevel inverter, presented DC/AC multilevel converter has less on-state voltage drop and conduction losses. Finally, in order to verify the theoretical issues, simulation and experimental results are presented. Keywords: DC-DC converter, Single input multi output, Voltage balancing 1. Introduction Multilevel voltage source inverters provide a cost effective solution in the medium and high voltage systems. These converters have been widely applied to power generation, energy transmission, drives and power quality devices [1-5]. Nowadays, there exist different commercial topologies of multilevel voltage source inverters. The famous types of multilevel voltage source inverters are: neutral point clamped (NPC), flying capacitors (FC) and cascaded H-bridge (CHB) [3-6]. In comparison with the two-level have some advantages as: y production of high power quality waveforms y production of waveforms with lower harmonic components y using lower voltage ratings of devices y lower switching losses y reduction of dv / dt stresses on the load y the possibility of working with low speed semiconductors The main disadvantage associated with the multilevel configurations is their circuit complexity, requiring a high number of power switches; they also require a great number of DC sources, provided either by independent supplies or, more commonly, by a cumbersome array of capacitive voltage dividers. Recently, several multilevel inverter topologies have been developed for multilevel inverters. Novel topologies of multilevel inverters using a reduced number of switches, gate driver circuits and DC sources are presented in recent years [7-10]. In [7] and [8] novel configuration of multilevel inverters have been proposed. The suggested topologies need fewer switches and gate driver circuits. The proposed structure in [7] requires multiple DC sources. The converter power stage under study in [8] consists of an H-Bridge, bidirectional auxiliary switches, and an n-level capacitor voltage divider. In this case, ensuring that the DC voltages are kept in equilibrium is another factor that increases the complexity of the circuit. Recently cascaded transformer multilevel topology is proposed [9, 10]. This has the advantage of having single DC source for all its cells. These topologies use of transformers in their structures. However, transformers have some disadvantages such as heavy weight, large size, sensitivity to harmonics, voltage drop under load, requiring protection from system disturbances and overload, and environmental concerns regarding mineral oil [11, 12]. In recent years, significant advances in power semi- conductor device technology have led to a number of multistage power converter topologies. A new type of converter based on power electronics has been introduced [13, 14]. This paper presents a new topology of multilevel inverter that improves the previous topologies and enhances its performance. This converter is a two stage converter. In the proposed topology, one type of multilevel inverter and one type of DC-DC converter have been integrated to reduce the number of switches and DC sources. The DC- DC converter is a multi-output boost converter. This configuration can be utilized instead of several single output DC power supplies. One type of multilevel inverter with a small number of switching devices is used in the second stage of converter. It consists of an H-bridge and an inverter which outputs multilevel voltage by switching the DC voltage sources in series. The proposed topology is called SIBMI (Single input boost multilevel inverter). To verify the feasibility of the proposed multilevel inverter; † Corresponding Author: Electrical Engineering Department, Faculty of Engineering, Azarbaijan Shahid Madani University, Iran. (m.banaei @ azaruniv.edu) * Electrical Engineering Department, Faculty of Engineering, Azarbaijan Shahid Madani University, Iran. Received: September 17, 2013; Accepted: December 28, 2013 ISSN(Print) 1975-0102 ISSN(Online) 2093-7423