A decompose-reshape-ensemble deep learning framework for multi-scale short-term photovoltaic power forecasting

Accurate short-term photovoltaic (PV) power forecasting is critical for maintaining grid stability and enabling efficient dispatch in modern sustainable power systems, yet the inherent volatility and multi-scale temporal dynamics of PV output remain challenging for existing methods. This paper proposes IFTMC, a novel hybrid framework that synergistically integrates improved complete ensemble empirical mode decomposition with adaptive noise (ICEEMDAN), fuzzy C-means (FCM) soft clustering, and dual-backbone deep learning networks-TimesNet and Mamba-coupled through a bidirectional cross-attention fusion mechanism. Specifically, ICEEMDAN decomposes the raw PV power series into intrinsic mode functions of distinct frequency scales, which are subsequently regrouped via FCM clustering to reduce modelling complexity while preserving inter-band transitional information. TimesNet and Mamba then operate as complementary feature extractors, capturing multi-periodic local patterns and long-range temporal dependencies, respectively, with cross-attention adaptively allocating their contributions according to input conditions. Extensive experiments on the DKASC benchmark dataset demonstrate that IFTMC achieves state-of-the-art performance, reducing mean absolute error (MAE) by 4.2%-4.8% relative to the strongest baseline across 2-3-hour prediction horizons. Comprehensive ablation studies, case analyses under diverse weather conditions, and attention weight visualizations further confirm the effectiveness, robustness, and interpretability of each component.