11-Level Operation With Voltage-Balance Control of WE-Type Inverter Using Conventional and DE-SHE Techniques

Mohammad Ali,Mohd Tariq,Michael J Ryan,Basem Alamri,Ripon K Chakrabortty,Mohammed A Bou-Rabee

doi:10.1109/access.2021.3072905

Abstract

This article presents an 11-level operation of the WE (Wee)-Type inverter. The topology employs a single DC-source, has a reduced number of components, and exhibits a boosting capability. A voltage balancing algorithm is proposed where the inverter’s redundant states are employed to maintain the auxiliary DC-link voltage. It is shown that with the control algorithm, the link voltage is preserved at half the primary DC-link voltage, and the 11-level operation is possible for any load. The presented 11-level WE-type structure is also compared with recent 11-level structures and has a lowest cost factor. Two modulation strategies verify the 11-level operation of the inverter: first, a modified nearest level control (MNLC) with the usage of both zero states is developed; and, second, selective harmonic elimination (SHE) is employed, where the angles are generated using a differential evolution (DE) technique. The maximum efficiency of the inverter is 97.55 %. The performance of the inverter is validated in MATLAB/Simulink and on the hardware-in-the-loop platform.

Highlights

Multilevel inverters (MLI) are gaining much popularity in the research community and industry for applications such as renewable energy source integration [1], and medium and high voltage drives [2] as they produce near-sinusoidal waveforms and exhibit reduced dv/dt and di/dt stresses on the switches
Structure employs a large number of clamping diodes, and the cascaded H-bridge (CHB) structure requires as many DC sources as the number of H-bridges employed [5]
This work presents an 11-level operation of a WE-type inverter in which the voltages across the capacitors is balanced by using the redundant states

Summary

INTRODUCTION

Multilevel inverters (MLI) are gaining much popularity in the research community and industry for applications such as renewable energy source integration [1], and medium and high voltage drives [2] as they produce near-sinusoidal waveforms and exhibit reduced dv/dt and di/dt stresses on the switches. The conventional NPC and FC topologies employ symmetrical sources and require a large number of switches and capacitors, and is sometimes referred to as silicone grave in the industry when 5 or 7 level structures are discussed [6], [7]. This work presents the 11-level operation of the same structure by balancing the voltage across the auxiliary DC link at Vdc/2. This work presents an 11-level operation of a WE-type inverter in which the voltages across the capacitors is balanced by using the redundant states. It is modulated by employing two methods. The switches S1, S1, S2 and S2 are subjected to maximum voltage, which is Vdc, S3, S3, S4, S5 and S5 are

WE-TYPE INVERTER SWITCHING STATES AND MODELING

CAPACITOR VOLTAGE BALANCING ALGORITHM

POWER LOSS ANALYSIS

RESULTS AND DISCUSSION

VIII. CONCLUSION