scholarly journals Analytical Modelling and Verification of Bus-Clamping Modulation Technique for Switched-Capacitor Converter

2017 ◽  
Vol 2017 ◽  
pp. 1-10
Author(s):  
Amarnath Yalavarthi ◽  
Akbar Ahmad

Space vector modulation techniques have advantages of high output voltages and reduced harmonic content as they utilize the dc bus effectively. Bus-clamped pulse width modulation classified in space vector techniques has the ability to reduce the switching losses of the converter and has reduced harmonic distortion. This paper provides mathematical analysis for 60-degree bus-clamping strategy to obtain the complete closed-form solution for finding the harmonic coefficients using double Fourier integral expression. The effectiveness of the bus-clamped approach on switched capacitor based multilevel inverter has been shown with comparison to Sinusoidal PWM. The DSP controller TMS320F240 has been chosen for the real-time implementation of 60-degree bus-clamping modulation technique. Simulation and experimental results of the prototype are presented for RL load at different modulation indices showing the superiority of the configuration to cascaded multilevel inverter.

2014 ◽  
Vol 622 ◽  
pp. 133-139
Author(s):  
Jayabal Gayathri Monicka ◽  
Venkatesan Jamuna ◽  
Kannakumar Hemalatha

This paper presents performance features of Symmetric and Asymmetric Cascaded Multilevel inverter. Both the Phase shifted and level shifted multicarrier pulse width modulation (MCPWM) technique are used in MLI. The best harmonic performance is improved by Level-shifted multicarrier modulations technique . The objective of this work to propose MCPWM Technique for multilevel inverter with equal and unequal DC sources. The Performances indices like Total Harmonic Distortion (THD), reduction of switches and number of DC Sources is considered. An appropriate method to achieve the MC modulation technique is also presented in this paper.


Author(s):  
D. Sandhya Rani ◽  
A. Appaprao

Multilevel inverters are increasingly being used in high-power medium voltage applications due to their superior performance compared to two-level inverters. Among various modulation techniques for a multilevel inverter, the space vector pulse width modulation (SVPWM) is widely used. The complexity is due to the difficulty in determining the location of the reference vector, the calculation of ontimes, and the determination and selection of switching states. This paper proposes a general SVPWM algorithm for multilevel inverters based on standard two-level SVPWM. Since the proposed multilevel SVPWM method uses two-level modulation to calculate the on-times, the computation of on-times for an n-level inverter becomes easier. The proposed method uses a simple mapping to achieve the SVPWM for a multilevel inverter. A general n-level implementation is explained, and experimental results are given for two-level and three-level inverters.


Author(s):  
Tamiru Debela ◽  
Jiwanjot Singh

Abstract Multilevel inverters (MLIs) have formed a new wave of interest in research and industry. Switched capacitor-based multilevel inverters are used to avoid the need for multiple separated DC sources compared to cascaded MLIs. However, the inclusion of several capacitors creates problems such as high inrush current, voltage imbalance. To avoid these drawbacks, this paper proposes an isolation-based scheme by using a flyback converter in the switched capacitor multilevel inverter. Further, the overall topology provides step-up AC voltage across the load from a single DC source with fewer power switches. To generate a step-up five-level voltage across the load, switched capacitor-based multilevel inverter needs six power switches and only one capacitor. To get the appropriate switching operation to generate the NL-levels, phase disposition pulse width modulation (PD-PWM) has been developed. The extended nine-level S 2 -MLI is also discussed in this paper under different conditions as change in input source voltage and dynamic load change. Moreover, to prove the superior performance of switched-capacitor single DC source multilevel inverter (S2-MLI), comparative analysis with existing single DC source MLI has been performed. The effectiveness and feasibility of the proposed topology are tested with varieties of loads by simulation using Matlab/Simulink. To validate the simulation results, hardware implementation has been done of five-level S2-MLI considering resistive and motor load by using DSpace 1103 controller.


Author(s):  
Sasmita Behera ◽  
Matruprasad Jyotiranjan

Wind is a source for generating clean and economical electrical energy with a proper harnessing mechanism. For a wind energy conversion system (WECS), maximum power extraction with optimum power quality is required. In this article, the grid power quality is enhanced, using a multilevel inverter which provides smoother and pure sinusoidal waves as compared to two-level inverter by decreasing total harmonic distortion (THD) in WECS with a permanent magnet synchronous generator (PMSG). Also, a maximum power point tracking (MPPT) algorithm is based on an optimal torque controller, employed to extract more power. In this study, a WECS with a PMSG connected to the local linear resistive load and grid is considered for simulation. A multilevel inverter grid interface is controlled by in phase disposition pulse width modulation (IPD – PWM). The multilevel inverter with MPPT has been acknowledged as superior to a normal two-level inverter without MPPT Controller. Simulation results as observed for fixed and variable wind speed including MPPT demonstrate benefits of the proposed method.


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