A Novel Asymmetric Circular Multilevel Inverter Topology with Reduced Number of Components and Improved Performance

In this paper, a novel Asymmetric Circular Multilevel Inverter (AC-MLI) that eliminates the need for a polarity generator is proposed. The proposed configuration is increased with multi-stages to achieve 7- and 15-level output voltage. Several algorithms are defined to determine the magnitude of the DC voltage sources, which are scaled asymmetrically to achieve higher degrees of voltage. From this, the optimal algorithm, which yields a higher voltage level, is selected for the design. Further, the suggested inverter is compared with various MLIs and conventional inverters to evaluate the advantage of the proposed topology. To investigate Total Harmonic Distortion (THD) reduction and voltage level improvement, the three-stage AC-MLI is simulated in MATLAB using conventional Pulse Width Modulation (PWM), Optimized Level Shifted-PWM (OLS-PWM) and Repository PWM (REPO-PWM) techniques, tested with resistive, inductive and motor loads. OLS-Phase Opposition and Disposition (POD) has achieved high efficiency and least THD. Moreover, the factors like Weighted THD (WTHD), Harmonic Spread Factor (HSF) and Distortion Factor (DF) are calculated for the developed 15-level AC-MLI. To evaluate its effectiveness, the proposed AC-MLI is implemented in real time and tested under dynamic operating conditions. This ensures the proposed AC-MLI generates high-quality output with minimal component count.