A novel extendable multilevel inverter for efficient energy conversion with fewer power components: Configuration and experimental validation

Abstract

Multilevel inverters (MLIs) are widely used in various sectors of power electronics. Some major benefits of using MLI are the high-quality voltage output, harmonic reduction, and efficiency. However, MLIs also bear a range of disadvantages including an excessive number of components, high total standing voltage (TSV), and complicated control scheme. Thus, a novel cross-switched neutral point clamped (CSNPC) nine-level inverter is proposed. Many of the suggested MLIs use a large number of DC supplies and additional switches that are not fully utilized and generate high power loss. However, the proposed MLI topology has a smaller number of power electronic switches and DC supplies, leading to higher energy efficiency. Moreover, a simplified high frequency modulation technique, named hysteresis-band-based discontinuous pulse width modulation (DPWM) is devised to control the proposed MLI. This modulation scheme has effectively minimized capacitor voltage imbalance. Furthermore, the designed structure is extendable to a modular MLI, without any additional H-bridge circuit. To verify its benefits over other recent similar types of MLIs, a thorough comparison is presented for the number of components and power losses. The proposed MLI has showed 95.54% efficiency, and the modular CSNPC can achieve a total harmonic distortion (THD) of 6.43%.