International Journal of Power Electronics and Drive Systems (IJPEDS) Vol. 13, No. 1, March 2022, pp. 500~508 ISSN: 2088-8694, DOI: 10.11591/ijpeds.v13.i1.pp500-508  500 Journal homepage: http://ijpeds.iaescore.com Study of novel parallel H-bridge and common-emitter current- source inverters for photovoltaic power conversion system Suroso, Hari Siswantoro Department of Electrical Engineering, Jenderal Soedirman University, Purbalingga, Indonesia Article Info ABSTRACT Article history: Received Jul 26, 2021 Revised Feb 8, 2022 Accepted Feb 15, 2022 A novel operation of three-level H-bridge and common-emitter current source inverters (CSIs) proposed for photovoltaic power converters is presented in this paper. Two photovoltaic systems with two different inverter circuits, i.e. H-bridge and common-emitter CSIs, were connected in parallel to supply a sharing ac power load. In order to regulate the power supplied by each inverter system, proportional integral current controllers were employed. Triangular carrier and sinusoidal signals-based modulation techniques were implemented to both inverters. Some parameters such as load current, inverter’s output current, total harmonics distortion (THD), and efficiency were tested and analyzed. Test results showed that in the parallel operation of these inverters, the average THD percentage of the load current was 0.34% for load power factor 0.996 and 0.62 % for load power factor 0.782. Minimum waveform distortion of inverter ac currents during parallel operation can be achieved if the current magnitudes of both inverters were set the same. In the case of efficiency, the maximum efficiency of the system was 89.07%. Operating the H-bridge CSI with a higher magnitude of the output current will result in higher efficiency of the system. Keywords: Inverter Parallel operation Photovoltaic This is an open access article under the CC BY-SA license. Corresponding Author: Suroso Department of Electrical Engineering, Engineering Faculty, Jenderal Soedirman University Mayjen Sungkono St. km. 5, Blater, Purbalingga, Central Java 53371, Indonesia Email: suroso.te@unsoed.ac.id 1. INTRODUCTION Recently, the application of renewable energy sources especially photovoltaic systems has been increasing in many countries around the world. It is because of some merits introduced by the photovoltaic system, such as reducing environmental pollution, low operating cost, and availability from a few watt power to a larger megawatt-scale system [1]−[4]. Simplicity in installation such as on rooftop is a feature that attracts more interest to photovoltaic for residential application [5]−[7]. Even more so, some governments issued policies giving incentives for the development of renewable energy sources such as photovoltaic power generator to increase its application in their countries. Fortunately, the latest efficiency of a photovoltaic module has achieved 47.1%, realized by using multi-junction concentrator solar cells [8]. It will boost the total efficiency of solar energy conversion into electrical energy. Moreover, the availability of supporting technologies such as photovoltaic power converters is also another important factor to increase the wider application of the photovoltaic system. Power electronic converters are essential parts of the development of renewable energy applications [9] −[11]. Some renewable energy sources generate electrical energy in the form of dc power, such as photovoltaic systems, and fuel cells. The generated power of other energy sources such as micro hydro power, wind power system, tidal, and sea wave energies are commonly in the form of ac power. They use an ac machine generator to produce electrical