Multi-Level Cascaded Inverter (MLCI) Design, Simulation and Implementation with Solar Photovoltaic System Modeling

Location

Nessmith-Lane Atrium

Session Format

Poster Presentation

Research Area Topic:

Engineering and Material Sciences - Electrical

Abstract

This research proposes design, modeling and implementation of a multi-level cascaded inverter for a single-phase connected photovoltaic system with its associated control issues. The cascaded inverter is chosen because of its ability to produce stepped voltage without using a transformer. It is light, compact, and cheaper (25% cheaper) than other multilevel inverters. They also require minimum effort to operate on AC and DC. This system will convert power from DC to AC and will use battery storage for times when solar energy is absent. The cascaded inverter consists of two full bridge topologies and AC outputs in series. Each bridge has the ability to produce three different voltage outputs. In addition to the inverter a low pass filter will also be needed to eliminate the switching ripples. The output voltage waveforms in multilevel inverters can be generated at low switching frequencies with low distortion and high frequency. The term multilevel began with the three level converter. Subsequently, several multilevel converter topologies have been developed. In this work, a single level, three level, nine levels and twenty one levels are proposed using MATLAB/Simulink. The proposed configuration reduces the complexity in design and modularity when compared to conventional method which also provides reduced switching losses and harmonics. A multilevel shifted carrier based sinusoidal PWM switching scheme is utilized to reduce the complexity in control design. The circuit performance is simulated and experimental results are tested using laboratory prototype and MOSFET switches along with their driver circuits. The simulation, comparison and validation figures are presented too. From the comparison, it is clear that we get low harmonics with reduced number of components when compared to conventional methods. Harmonic spectrum is analyzed to prove its efficiency in reducing output harmonic components. Simulated and experimental output waveforms were shown to prove the reliability and feasibility of the circuit. From the different levels of simulation it is clear that THD can be decreased by increasing number of levels which validates the proposed control strategy. Finally, a portable 100 w photovoltaic system will be tested with two types of inverter: first connected to power inverter with deep cycle battery to act as stand-alone photovoltaic system, and second connected to grid-tie inverter with deep cycle battery to work in both modes without isolation from Power Company. The measurements for the two cases are taken and used with the aid of powerful regression technique (Artificial Neural Network) to implement global modeling for the system. Photovoltaic energy system is used due to the increasing importance of alternate energy sources research.

Presentation Type and Release Option

Presentation (Open Access)

Start Date

4-16-2016 2:45 PM

End Date

4-16-2016 4:00 PM

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Apr 16th, 2:45 PM Apr 16th, 4:00 PM

Multi-Level Cascaded Inverter (MLCI) Design, Simulation and Implementation with Solar Photovoltaic System Modeling

Nessmith-Lane Atrium

This research proposes design, modeling and implementation of a multi-level cascaded inverter for a single-phase connected photovoltaic system with its associated control issues. The cascaded inverter is chosen because of its ability to produce stepped voltage without using a transformer. It is light, compact, and cheaper (25% cheaper) than other multilevel inverters. They also require minimum effort to operate on AC and DC. This system will convert power from DC to AC and will use battery storage for times when solar energy is absent. The cascaded inverter consists of two full bridge topologies and AC outputs in series. Each bridge has the ability to produce three different voltage outputs. In addition to the inverter a low pass filter will also be needed to eliminate the switching ripples. The output voltage waveforms in multilevel inverters can be generated at low switching frequencies with low distortion and high frequency. The term multilevel began with the three level converter. Subsequently, several multilevel converter topologies have been developed. In this work, a single level, three level, nine levels and twenty one levels are proposed using MATLAB/Simulink. The proposed configuration reduces the complexity in design and modularity when compared to conventional method which also provides reduced switching losses and harmonics. A multilevel shifted carrier based sinusoidal PWM switching scheme is utilized to reduce the complexity in control design. The circuit performance is simulated and experimental results are tested using laboratory prototype and MOSFET switches along with their driver circuits. The simulation, comparison and validation figures are presented too. From the comparison, it is clear that we get low harmonics with reduced number of components when compared to conventional methods. Harmonic spectrum is analyzed to prove its efficiency in reducing output harmonic components. Simulated and experimental output waveforms were shown to prove the reliability and feasibility of the circuit. From the different levels of simulation it is clear that THD can be decreased by increasing number of levels which validates the proposed control strategy. Finally, a portable 100 w photovoltaic system will be tested with two types of inverter: first connected to power inverter with deep cycle battery to act as stand-alone photovoltaic system, and second connected to grid-tie inverter with deep cycle battery to work in both modes without isolation from Power Company. The measurements for the two cases are taken and used with the aid of powerful regression technique (Artificial Neural Network) to implement global modeling for the system. Photovoltaic energy system is used due to the increasing importance of alternate energy sources research.