To enhance the operational efficiency of energy storage converters in grid-connected systems with high renewable penetration, this study systematically investigates key technologies of active neutral-point clamped (ANPC) topology under “electrical–thermal–mechanical” multi-physical field coupling. The study reviews recent progress in structural design, modulation strategies, and fault-tolerant control, highlighting their impact on efficiency, reliability, and power density. At the structural stage, a hybrid SiC/IGBT device configuration combined with a three-dimensional stacked bus reduces conduction loss and achieves parasitic inductance. In the modulation stage, improved finite-set model predictive control and adaptive space vector modulation shorten computation time to 20 µs and keep total harmonic distortion (THD) within 2.8%. System-level evaluations demonstrate that a 250 kW ANPC converter attains a peak efficiency of 99.1%, a power density of 4.5 kW/kg, and a mean time between failure exceeding 150,000 h. These findings reveal a clear transition from single-objective performance improvement toward integrated multi-physics co-design. By unifying advanced modulation, intelligent fault-tolerant control, and multi-field coupling optimization, ANPC-based converters advance converters to a new stage of higher efficiency, reliability, and stability. The results provide essential technical support for next-generation power conversion systems in renewable-rich grids.

Under the background of “dual-carbon” strategy and global energy transition, the metallurgical industry, which accounts for 15–20% of industrial energy consumption, urgently needs to reduce the energy consumption and emission of DC power supply of electric furnaces. Aiming at the existing 400–800 V/≥3000 A industrial-frequency transformer-rectifier system with low efficiency, large volume, heat dissipation difficulties and other bottlenecks, this thesis proposes and realizes a high-frequency integrated DC power supply scheme for high-power electric furnaces: high-frequency transformer core and rectifier circuit are deeply integrated, which breaks through and reduces the volume of the system by more than 40%, and significantly reduces the iron consumption; multiple cores and three windings in parallel are used for the system. The topology of multiple cores and three windings in parallel enables several independent secondary stages to share the large current of 3000 A level uniformly, eliminating the local overheating and current imbalance; the combination of high-frequency rectification and phase-shift control strategy enhances the input power factor to more than 0.95 and cuts down the grid-side harmonics remarkably. The authors have completed the design of 100 kW prototype, magneto-electric joint simulation, thermal structure coupling analysis, control algorithm development and field comparison test, and the results show that the program compared with the traditional industrial-frequency system efficiency increased by 12–15%, the system temperature rise reduced by 20 K, electrode voltage increased by 10–15%, the input power of furnace increased by 12%, and the harmonic index meets the requirements of the traditional industrial-frequency system. The results show that the efficiency of this scheme is 12–15% higher than the traditional IF system, the temperature rise in the system is 20 K lower, the voltage at the electrode end is 10–15% higher, the input power of the furnace is increased by 12%, and the harmonic indexes meet the requirements of GB/T 14549, which verifies the value of the scheme for realizing high efficiency, miniaturization, and reliable DC power supply in metallurgy.

In cascaded H-bridge (CHB) high-voltage drives using unipolar frequency-doubling carrier phase-shifted sinusoidal pulse width modulation (CPS-SPWM), unequal carrier phase offsets weaken switching-harmonic cancelation. This paper proposes a carrier-synchronization method that improves timing accuracy without adding dedicated synchronization fibers. The start edge of the downlink data frame is multiplexed as the common timing reference, hardware timer input capture removes interrupt-response latency from edge acquisition, and a dual-stage strategy combines standstill hard alignment with rate-limited on-line soft alignment. A phasor model links synchronization error to residual carrier-group amplitude and establishes a conservative accuracy target below 5 μs. On a complete 36-cell prototype, the measured spatial root-mean-square phase-offset deviation across the 11 Phase-A cell pairs referenced to A1 is 0.22° (1.22 μs), and the maximum absolute inter-cell phase-offset deviation is 0.36° (2.00 μs). A 380 V cascaded-output test confirms the expected 12 kHz dominant ripple and strong suppression of the 500 Hz and 1 kHz sidebands. Compared with a dedicated synchronization-link architecture, the proposed scheme halves the fiber and transceiver counts, requires only three pin-to-pin connections per-cell controller, and preserves address-free unified firmware. The method therefore provides a practical accuracy-cost compromise for large CHB systems, while full-voltage electromagnetic-compatibility validation remains future work.

This narrative review examines the design of power electronics for deep-sea energy and industrial systems, where converter performance is constrained by electrical demands and prolonged exposure to pressure, seawater, temperature cycling, and limited maintenance access. Targeted, non-systematic literature searches covering studies available through September 2026 were used to connect offshore renewable generation and hydrogen production, sub-sea distribution and motor drives, and autonomous underwater vehicle (AUV) power and charging. The review organizes published evidence around converter topology, semiconductor and passive-component selection, switching and conduction losses, insulation coordination, thermal paths, protection, and environmental qualification. It identifies distinct design priorities: high-voltage insulation and fault isolation for sub-sea distribution; continuous-current capability and ripple control for hydrogen interfaces; and compact conversion, energy budgeting, and misalignment-tolerant charging for AUVs. Hydro-static pressure and sealing alter heat-transfer and insulation boundaries, while vibration, corrosion, and cycling create interacting failure pathways. Consequently, efficiency or power-density figures measured under different electrical loads, pressure conditions, cooling arrangements, and test duration cannot be ranked directly. A mission-specific design and verification pathway is proposed, beginning with explicit operating boundaries and component-level screening, followed by combined-stress tests, converter prototypes, and system-level trials. The proposed pathway also incorporates monitoring, maintainability, and life-cycle assessment. Published demonstrations substantiate individual technical options, but they do not establish a universally optimal architecture or long-term sub-sea reliability. Future studies should report comparable measurement boundaries, failure criteria, and exposure histories so that converter designs can be evaluated against the demands of their intended missions under repeatable, application-relevant conditions and declared measurement uncertainty.