A Novel Dual-Input Switched-Capacitor Based 27-Level Boost Inverter Topology

A single-phase step-up switched-capacitor based 27-level inverter topology is proposed that is capable of supplying resistive-inductive (R-L) loads. The suggested structure produces 27 voltage steps and gain of 1.3 with 2 DC supplies, 13 unidirectional switches, 13 driver boards, 2 capacitors, and 1 diode. The voltage balancing of capacitors takes place naturally, which eases the control of converter. The low voltage ripple on capacitors leads to low Total Harmonic Distortion (THD=1.9_%) and better power quality, which reduces the size of end-side filter. The reduced elements, low Normalized Standing Voltage (NSV) and low Total Standing Voltage (TSV) on semiconductors are the other advantages. The application of 2 full-bridges imposes less Peak Inverse Voltage (PIV) on output-side switches. Also, the employment of fundamental frequency (nearest level) method for switching pulse generation reduces the switching losses. The comparison and simulation outcome highlight the benefits and correct operation of suggested inverter.

I. Introduction

Increasing importance of high-quality voltage generation in the industry, as well as lower cost, increases the trend towards the Multi-Level Inverters (MLIs) [1], [2]. Although, multilevel inverters have many advantages such as low THD, high quality, low EMI and low Standing Voltage (SV) on semiconductors, but using only DC voltage sources to produce different output voltage steps makes these structures devoid of any voltage gain feature [3]–[7]. Since the voltage gain has paramount importance in Renewable Energy Systems (RES) and Photo-Voltaic (PV) applications, the Switched-Capacitor MLIs (CSMLIs) have been presented [8], [9]. Usually, the SCMLIs have acceptable gains, however, there are still some with unity gain [10]–[12].