Switched capacitor based single DC source boost multilevel inverter (S2-MLI) featuring isolation based soft charging with minimum device count

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.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Jagabar Sathik ◽  
Dhafer J. Almakhles ◽  
N. Sandeep ◽  
Marif Daula Siddique

AbstractMultilevel inverters play an important role in extracting the power from renewable energy resources and delivering the output voltage with high quality to the load. This paper proposes a new single-stage switched capacitor nine-level inverter, which comprises an improved T-type inverter, auxiliary switch, and switched cell unit. The proposed topology effectively reduces the DC-link capacitor voltage and exhibits superior performance over recently switched-capacitor inverter topologies in terms of the number of power components and blocking voltage of the switches. A level-shifted multilevel pulse width modulation scheme with a modified triangular carrier wave is implemented to produce a high-quality stepped output voltage waveform with low switching frequency. The proposed nine-level inverter’s effectiveness, driven by the recommended modulation technique, is experimentally verified under varying load conditions. The power loss and efficiency for the proposed nine-level inverter are thoroughly discussed with different loads.


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.


2021 ◽  
Vol 6 (1) ◽  
pp. 63-73
Author(s):  
Hossein Khoun-Jahan ◽  

Cascaded multilevel inverter (CMI) topology is prevalent in many applications. However, the CMI requires many switches and isolated dc sources, which is the main drawback of this type of inverter. As a result, the volume, cost and complexity of the CMI topology are increased and the efficiency is deteriorated. This paper thus proposes a switched-capacitor-based multilevel inverter topology with half-bridge cells and only one dc source. Compared to the conventional CMI, the proposed inverter uses almost half the number of switches, while maintaining a boosting capability. Additionally, the main drawback of switched-capacitor multilevel inverters is the capacitor inrush current. This problem is also averted in the proposed topology by using a charging inductor or quasi-resonant capacitor charging with a front-end boost converter. Simulation results and lab-scale experimental verifications are provided to validate the feasibility and viability of the proposed inverter topology.


Author(s):  
Mahajan Sagar Bhaskar ◽  
Sanjeevikumar Padmanaban ◽  
Frede Blaabjerg ◽  
Anzari Mohammed

Inverters are Power Electronic System (PES) and proficient to converting Direct Currents (DC) into Alternating Currents (AC). Conventional two-level inverter has drawbacks like high Total Harmonic Distortions (THD), high voltage across power switch, high dv/dt of output voltage and electromagnetic interferences. Multilevel Inverters (MLIs) are employed to overcome the drawbacks of conventional two-level inverter. Multilevel Inverters generate an AC voltage using small voltage steps obtained with the help of DC supplies or capacitor banks. This paper deals with the implementation of a Transistor Clamped H-Bridge Multilevel Inverter (TCHB-MLI) using Inverted Double Reference Single Carrier Pulse Width Modulation (IDRSCPWM) technique for photovoltaic application. The proposed TCHB-MLI requires less number of power switches and drivers to achieve maximum number of output level. The analysis of the multilevel inverter output is done in terms of its harmonic spectrum, output voltage and output current for modulation indices 0.85, 1 and 1.25. The control signals for the power switches of the proposed TCHB-MLI are developed by using SPARTAN 3E-XCS250E trainer kit. Experimental results will verify the functionality, design of the proposed TCHB-MLI and IDRSCPWM Technique.


2021 ◽  
Vol 20 (2) ◽  
pp. 1-7
Author(s):  
Jahanzeb - ◽  
Shahrin Md. Ayob ◽  
Saifullah Khan ◽  
Mohd Zaki Daud ◽  
Razman Ayop

There is always a need to create efficient and optimized converters to deliver the best possible results to achieve a better THD profile in the waveform output. One way is by controlling the switching of the power switches of the converters using appropriate modulation schemes. While numerous works have been done in proposing new switching modulation strategies for multilevel inverters, this work will compare multicarrier PWM and near-to-level control (NLC) modulation schemes. In this paper, multicarrier PWM variants, namely, PD-PWM, POD-PWM, and APOD-PWM, are designed and simulated. Their voltage THD and spectrum performance are discussed when applied to single-phase 7, 9, and 11-level cascaded multilevel inverters. Then NLC modulation will be designed and applied to similar multilevel inverter circuits. It will be shown that the NLC exhibits some superior performances compared to PWM-based but with several drawbacks that can be optimized. 


This paper describes on a new compilation of micro grid era the usage of multilevel inverter. In this paper we have linked three renewable resources are parallel like wind turbine, PV cellular and Pico Hydel generator set to deliver strength to a exceptionally small assortment of residential, reputable of business building in a locality. The electricity is generated from renewable power resources and it's far connected to space vector primarily based multilevel inverter. Therefore the power is completely computerized for this reason the strength losses can be less, reduced switching sample losses and grids have the capacity to reply robotically to the versions in electric parameters answerable for the clean functioning of the grid [1]. Moreover, decrease prices of power switches in the new semiconductor technologies as well as the current demand on excessive overall performance inverters required through Renewable Energy Systems (RES) decreased total Harmonic distortion(THD) within the spectrum of switching waveform have extended the programs of Multilevel inverters


Author(s):  
N. Susheela ◽  
P. Satish Kumar

<p>The popularity of multilevel inverters have increasing over the years in various applications without use of a transformer and has many benefits. This work presents the performance and comparative analysis of single phase diode clamped multilevel inverter and a hybrid inverter with reduced number of components. As there are some drawbacks of diode clamped multilevel inverter such as requiring higher number of components, PWM control method is complex and capacitor voltage balancing problem, an implementation of hybrid inverter that requires fewer components and less carrier signals when compared to conventional multilevel inverters is discussed. The performance of single phase diode clamped multilevel inverter and hybrid multilevel inverter for seven, nine and eleven levels is performed using phase disposition, alternate phase opposition disposition sinusoidal pulse width modulation techniques. Both the multilevel inverter are implemented for the above mentioned multicarrier based Pulse Width Modulation methods for R and R-L loads.  The total harmonic distortion is evaluated at various modulation indices. The analysis of the multilevel inverters is done by simulation in matlab / simulink environment.</p>


Multilevel inverters are widely used for high power and high voltage applications. The performance of multilevel inverters are superior to conventional two level inverters in terms of reduced total harmonic distortion, higher dc link voltages, lower electromagnetic interference and increased quality in the output voltage waveform. This paper presents a single phase hybrid eleven level multilevel inverter topology with reduced switch count to compensate the above mentioned disadvantages. This paper also presents various high switching frequency based multi carrier pulse width modulation strategies such as Phase Disposition PWM Strategy (PDPWM), Phase Opposition and Disposition PWM Strategy (PODPWM), Alternate Phase opposition Disposition PWM (APODPWM), Carrier Overlapping PWM (COPWM), Variable frequency carrier PWM (VFPWM), Third Harmonic Injection PWM (TFIPWM) applied to the proposed eleven level multilevel inverter and is analyzed for RL load. FFT analysis is carried out and total harmonic distortion, fundamental output voltage are calculated. Simulation is carried out in MATLAB/SMULINK.


Author(s):  
Saifullah Kakar ◽  
S. M. Ayob ◽  
M. Saad Bin Arif ◽  
N.M. Nordin ◽  
Z. Daud ◽  
...  

This paper presents a new multilevel inverter based on the switched-capacitor technique. The topology aims for renewable energy and fuel cell applications that demand high magnitude output ac voltage. This configuration of the inverter can produce a total of thirteen voltage levels using a single DC source. The topology features voltage boosting with a triple gain of the input voltage source without utilizing a boost DC-DC converter. Furthermore, the voltages of the capacitors are self-balanced at any desired voltage level during each cycle. Therefore, auxiliary circuits are no longer needed. A comparative study of the presented inverter with the classical topologies and recently introduced topologies has been done in power switches, driver circuits, blocking voltage of the switches, and boosting the input voltage. A simple fundamental switching scheme is applied to the proposed topology to validate the viability of the topology.


Author(s):  
Asef A. Saleh ◽  
Rakan Khalil Antar ◽  
Harith Ahmed Al-Badrani

The advantage of multilevel inverters is to produce high output voltage values with distortion as minimum as possible. To reduce total harmonic distortion (THD) and get an output voltage with different step levels using less power electronics switching devices, 15-level inverter is designed in this paper. Single-phase 11-switches with zero-level (ZL) and none-zero-level (NZL) inverter based on modified absolute sinusoidal pulse width modulation (MASPWM) technique is designed, modelled and built by MATLAB/Simulink. Simulation results explained that, multilevel inverter with NZL gives distortion percent less than that with ZL voltage. The THD of the inverter output voltage and current of ZL are 4% and 1%, while with NZL is 3.6% and 0.84%, respectively. These results explain the effectiveness of the suggested power circuit and MASPWM controller to get the required voltage with low THD.


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