To address the issues of limited soft-switching range and high inductor current peak in traditional single phase shift (SPS) modulation for AC–DC converters under a wide range of voltage conversion ratio conditions, this paper proposes an optimized modulation strategy based on SPS modulation. First, the steady-state operating characteristics under SPS modulation are analyzed, and the current-transfer equation is derived. A conversion coefficient is then introduced to transform the conventional phase-shift ratio into a new variable. Based on this, the time-domain characteristics of the inductor current peak and the constraints for zero voltage switching (ZVS) are analyzed. An analytical expression of the conversion coefficient is obtained, which ensures ZVS operation for all switches in the dual-active-bridge (DAB) converter and minimizes the inductor current peak. Finally, experiments verify the effectiveness and feasibility of the proposed modulation strategy.

Auxiliary frequency modulation (FM) for coal-fired units has been recognized as a promising approach through multiple batteries, which is due to their rapid charging and discharging characteristics. However, long-period engineering application needs continuous optimization of operational strategies to resist the decay characteristics of the battery, which greatly increases the difficulty of promotion. Hence, two replacement strategies of the battery were first proposed in this work, and they are characterized by simple operation. To test their feasibility, a lead–acid battery was selected as one study example, and the corresponding relationship between the duration day and the replacement scheme was emphatically analyzed, according to the AGC instruction and the self-adjustment capacity of coal-fired units. Results showed that the replacement capacity of the battery is nearly linear in the duration day, while the difference from the discharge depth is negligible in this study. In addition, the capacity ratio of 1.3 to 5 is considered to have the best application potential because of the same duration days between old and new batteries. The commutative replacement can immortally extend the duration day, and obviously, the replacement process of old and new batteries always maintains that two battery groups work. Conclusively, the case analysis for two replacement strategies showed that they deeply lowered the initial capacity of the battery, which can reduce the investment costs. In a word, two replacement strategies for the battery proposed in this study provide a reference for the economic evaluation and optimization of battery use for auxiliary FM.

Typhoons pose significant threats to power infrastructure, often leading to data center outages and critical data loss. To enhance power supply resilience, this paper proposes a refined spatiotemporal risk probability distribution prediction method based on the coupling model of WRF and FEDformer, as well as differentiated collaborative supply measures considering risk levels. First, a fault probability matrix is generated using the WRF physical model and the FEDformer temporal encoder to construct a power supply risk profile under complex typhoon scenarios. Then, a differentiated collaborative supply mechanism is proposed, based on non-critical load transfer and dedicated mobile energy storage, with an optimized two-stage robust optimization model constructed by classifying non-critical loads and optimizing transfer paths. Compared to traditional methods, the proposed approach can forecast the spatiotemporal distribution characteristics of data center risk probabilities under typhoon impact, and provide targeted differentiated supply measures according to prediction results. The accuracy of the proposed prediction model is verified using the “Yangliu” typhoon case. Simulation results indicate that the proposed strategy reduces voltage sag switching to only 3.8%, stabilizes frequency deviation within 0.12 Hz, improves power supply availability from 76.3% to 100%, enhances capacity margin by 250% through non-critical load transfer, and ensures power supply availability during extreme disasters using dedicated mobile energy storage.