Switched-Capacitor-Based Neutral-Point-Clamped Quasi-Switched Boost Multilevel Inverter

  • T. AjaykumarEmail author
  • Nita R. Patne
Research Article - Electrical Engineering


Reliable and efficient inverters are becoming essential in the current scenario of electrical power generation from renewable energy sources. Owing to inherent buck–boost ability and shoot-through immunity, the single-stage inverters are getting solid evaluation as compared to conventional inverters in the present era of renewable energy generation. However, the maximum attainable boosting of the single-stage inverters is limited by means of device stresses and spectral performance. This paper proposes a switched-capacitor-based quasi-switched boost neutral-point-clamped single-stage multilevel inverter. It is able to make desired AC output voltage in a single-stage conversion from a low-level DC voltage engendered by renewable sources such as fuel cell and PV cell. Further, it can attain high voltage gain at reduced voltage stresses on the switches, capacitors and diodes by cascading multiple switched-capacitor cells to quasi-switched boost network. The working principle and steady-state analysis of proposed topology are presented in order to obtain mathematical relation between input and output voltages. The effectiveness of the proposed inverter has been compared with other impedance-source multilevel inverters in terms of voltage gain, boosting capability, voltage stresses and efficiency. The operation of the proposed system is verified by MATLAB simulation. Also, a laboratory prototype is built and tested to verify the theoretical analysis.


Multilevel inverter Switched-capacitor Pulse width modulation (PWM) Single-stage conversion 

List of Symbols


Boost factor


Overall voltage gain of the inverter


Switching time period in seconds


Shoot-through (ST) duty ratio


Modulation index


DC input voltage from fuel cell or battery


Phase voltage w.r.t. DC bus neutral


Maximum inverter output voltage

\(V_{\text{in}}\), \(V_{{{\text{in}}(max)}}\)

Average and maximum DC-link voltage available at inverter input terminals


Voltage across the capacitors CX, CX1, CY and CY1, respectively


Voltage across the inductors LX and LY, respectively


Average current through DC link


Average currents through inductors LX and LY, respectively

iCX, iCY, iCX1, iCY1

Instantaneous currents through the capacitors CX, CY, CX1 and CY1, respectively


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Copyright information

© King Fahd University of Petroleum & Minerals 2019

Authors and Affiliations

  1. 1.Department of Electrical EngineeringVNITNagpurIndia

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