Analysis, Design and Investigation on a New Single-Phase Switched Quasi Z-Source Inverter for Photovoltaic Application

Abstract

This paper addresses the approach to improve the efficiency of the quasi Z-source inverter. In order to increase the efficiency the reduction of conduction losses is one way to approach. Sequentially to decrease the conduction losses in the quasi z-source inverter the replacement of diode is replacing with switches is proposed which is also called as synchronous rectification. The paper represents basics of the approach, analysis and comparison of the power losses of the traditional and proposed designs of the grid connected PV-system with quasi z-source inverter system. The proposed approach validated on the computer simulations in the MATLAB environment. Keyword:Inverter Photovoltaic application Quasi Z-source Copyright © 2017 Institute of Advanced Engineering and Science.All rights reserved.Corresponding Author:C. Bharatiraja, School Electrical and Electronics Engineering, SRM University, Chennai, India. Email: bharatiraja@gmail.com INTRODUCTIONThe quasi z-source inverters (q-ZSI) are drawing more attention than other impedance source networks in photovoltaic (PV) application due to its ability to deal with wide input voltage variation and its shoot-through capabilities and suitable for renewable energy system with large of gain. Feature of the qZSI is that it can draw continuous and constant current. The qZSI boost the input voltage by utilizing an extra switching state is the simultaneous conduction of both switches of the same leg in inverter-which is called as the shoot-through state [1]. This kind of operation forbidden in the traditional voltage source inverters (VSI) because it causes short circuit of the DC link capacitors.in the qZSI, shoot-through state is used to boost the magnetic energy stored in the dc-side inductors (L 1 and L 2 in Figure 1) without short-circuiting the dc capacitors C1 and C2. During this state, energy is first stored in the impedance network, and then released into the capacitors and load at non-shoot-through states. This increase in inductive energy, in turn, provides the boost of the output voltage VOduring the traditional operating states (active states) of the inverter.Most of the commercially available grid connected systems for renewable applications include a transformer, which enables the selection of a suitable dc voltage input for the inverter and isolates the energy source from the utility grid [2]. Converters including a transformer either use a line transformer or a highfrequency transformer. Line-frequency transformers are regarded as poor components due to increased size, weight, and prize. Converters with high-frequency transformers include various power stages and are pretty complex. In this paper a new system is proposed, which is having quasi z-source for the boost the voltage and inverter used as grid connected transformer-less system [3], which reduces size and cost. Unipolar pulse width modulation which is most commonly used PWM technique for this kind of system. To reduce the

A Hybridization of Cuk and Boost Converter Using Single Switch with Higher Voltage Gain Compatibility

“…Hence, the semiconductor must be selected to withstand the converter to provide maximum currents and voltages with a safety factor around 50%. The n-type reinforcing MOSFET is better chosen for providing the safety factor, and the proposed converter design uses the same [35]. The diodes (D 1 and D 2 ), and MOSFET switching losses and conduction losses were calculated and given in Equations ( 61)-(73).…”

“…Here, the switching frequency is less than an inductor magnetizing current frequency, which is not suitable for reliable operation. Recently, using the single switch in DC-to-DC power converters, various research papers have been published to derive high voltage gain without using a higher duty ratio [35][36][37][38][39][40]. The authors in [33] proposed a 2D/1-D voltage gain single switch buck-boost converter with low input current ripple and appropriate voltage gain.…”

High-Performance Sensorless Operation of Motor-Generator Set With an Improved Torque-Ripple Minimization Strategy

“…The motor-generator set is very spreading in most applications such as elevators, hybrid vehicles, and high-frequency machines (Hussien and Hassan, 2019). In the context of electric power generation and large fixed electrical power systems, a motor-generator consists of an electric motor mechanically coupled to an electric generator (or alternator) (Chokkalingam et al, 2019;Bharatiraja et al, 2017). The motor runs on the electrical input current while the generator creates the electrical output current, with power flowing between the two machines as a mechanical torque; this provides electrical isolation and some buffering of the power between the two electrical systems (Pandav et al, 2017b;Sanjeevikumar et al, 2016).…”

Experimental Verification of Single Phase Z Source Inverter for Photovoltaic Applications

“…[4] - [7] ZSI can be used to realize both DC voltage boost and DC-AC inversion in a single stage, an economical approach for photovoltaic applications. [8,9] The work reported in this paper is organized as: Mathematical model of photovoltaic panel in section 2, Topology description of single phase Z source inverter along with control strategy in section 3.Simulation and experimental results are presented in section 4. Finally, conclusion is reported in section 5.…”