A Current Allocation Strategy Based Balancing Technique of Voltage Source String in Switch-Ladder Inverter and Its Switched-Capacitor Variety

Author(s):  
Yat Chi Fong ◽  
Ka Wai Eric Cheng ◽  
Raghu Sekhar
2019 ◽  
Vol 11 (12) ◽  
pp. 3453 ◽  
Author(s):  
Taghvaie ◽  
Alijani ◽  
Adabi ◽  
Rezanejad ◽  
Adabi ◽  
...  

This paper presents a transformerless step-up multilevel inverter based on a switched-capacitor structure. One of the main contributions of the proposed topology is replacing the separated DC voltage source with capacitors which are charged at predetermined time intervals. Therefore, a high-level staircase voltage waveform can be achieved by discharging some of these capacitors on the load. The other contribution of the proposed structure is to eliminate the magnetic elements which traditionally boost the input DC voltage. In addition, asymmetrical or unequal amounts of capacitor voltages create more voltage levels, which enable voltage level increments without increasing the number of semiconductor devices. This paper introduces a self-balanced boost Switched-Capacitors Multilevel Inverter (SCMLI) which is able to create a nearly sinusoidal voltage waveform with a maximum voltage of up to 45 times that of the input voltage DC source. Higher level output voltage levels are also achievable by extending the circuit topology. After determination of the switching angles and selecting the proper switching states for each level, an offline NLC method is used for modulation, which eases the control implementation. Analysis, simulation and experiments are carried out for a 91-level inverter (45 levels for positive and negative voltages and one for zero voltage) are presented.


Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 524 ◽  
Author(s):  
Aryorad Khodaparast ◽  
Erfan Azimi ◽  
Ali Azimi ◽  
M. Ebrahim Adabi ◽  
Jafar Adabi ◽  
...  

A new structure of switched capacitor multilevel inverter (SCMLI) capable of voltage boosting and with self-balancing ability is introduced in this article. This advantage is the result of a step by step rise of capacitor voltages in each module, supplied by just one DC voltage source. The proposed topology generates a sinusoidal output waveform with a magnitude several times greater than the input one. Higher output staircase AC voltage is obtained by applying a nearest level control (NLC) modulation technique. The most significant features of this configuration can be mentioned as: fewer semiconductor devices, remarkably low total harmonic distortion (THD), desirable operating under high /low frequency, high efficiency, inherent bipolar voltage production, easy circuit expansion, ease of control and size reduction of the circuit thanks to utilizing neither bulky transformer nor inductor. Moreover, the proposed SCMLI is comprehensively surveyed through theoretical investigation and a comparison of its effectiveness to recent topologies. Eventually, the operating principle of a 25-level prototype of the suggested SCMLI is validated by simulation in the MATLAB SIMULINK environment and experimental results.


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):  
D.R. PATIL ◽  
KOMAL K. MADHALE

This paper presents the design of a prototype distribution static compensator (DSTATCOM) for voltage sag mitigation in an unbalanced distribution system. The D-STATCOM is intended to replace the widely used static Var compensator (SVC). The model is based on the Voltage Source Converter (VSC) principle. A new PWM based control scheme has been implemented to control the electronic valves in two level of VSC. The D-STATCOM injects a current into the system to mitigate the voltage sags. In this work, the 6-pulse D-STATCOM configuration with IGBT has been designed using MATLAB SIMULINK. Accordingly, simulations are first carried out to illustrate the use of D-STATCOM in mitigating voltage sag in a distribution system. Simulation results prove that the D-STATCOM is capable of mitigating voltage sag as well as improving power quality of a system.


2021 ◽  
Author(s):  
Arpan Hota ◽  
sumon dhara ◽  
venu sonti ◽  
sachin jain ◽  
Vivek Agarwal

<p>Zero common mode voltage (ZCMV) space vector modulation (SVM) strategy applied to a three-phase multilevel inverter (MLI) eliminates the common mode voltage (CMV). However, the usage of ZCMV-SVM strategy reduces the number of levels in the output voltage and requires higher magnitude dc voltage source due to the reduced modulation depth of the employed PWM scheme. Moreover, the usage of a single dc-source in such systems may have issues with respect to capacitor voltage balancing. Taking into account all the above issues, a 3-level inverter solution is proposed in this manuscript. The complete details of the method used for developing the proposed solution using the ZCMV space vectors is also included in this paper. The proposed topology utilizes a unique combination of a T-type 3-level inverter and a switched-capacitor (SC) circuit to achieve ZCMV performance with a single dc-source of low magnitude at a reduced component count. Analysis of the CMV and terminal voltages along with the design of the SCs are presented in this paper. The proposed topology is compared with the existing topologies to prove its unique merits over the other 3LI solutions with ZCMV capability. All the claims are validated using simulation and experimental results.</p>


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