Step-Wave AC Collection System: A More Efficient Solution for Wind and Photovoltaic Power Transmission

The sinusoidal alternating current (ac) synchronous generator-based power system has served as the backbone of electricity generation and distribution for over a century. However, to align with the evolving landscape of renewable energy sources and the power electronics-dominated high-voltage direct current (HVDC) transmission, this article innovatively proposes a fully step-wave ac collection system. This system aims to mitigate the losses inherent in electricity transmission and power conversion of renewable energy sources. The sending-end converter operates at a fundamental switching frequency of 50 or 60 Hz, significantly reducing switching losses. Furthermore, compared to sinusoidal systems, the proposed step-wave approach achieves a 15.5% improvement in dc voltage utilization for converters, leading to an estimated 25% reduction in conduction-type losses, while maintaining the same peak voltage stress across the entire system. We experimentally demonstrated the viability of utilizing a step-wave ac voltage and current framework. The step-wave system exhibited a remarkable 34.7% reduction in power losses compared to its sinusoidal counterpart. This innovative approach offers a potential solution for enhancing the efficiency and adaptability of modern power systems, tailored to the demands of power electronics-dominated grids.