Full Operating Range Optimization Design Method of LLC Resonant Converter in Marine DC Power Supply System

Abstract

The marine DC power supply system is the key to a ship’s power supply, which needs to convert the energy from storage batteries or distributed power generation units into stable DC voltage for electric propulsion or the ship’s electronics. The LLC resonant converter can be used as the key power conversion link in the marine DC power supply system due to its ability to realize electrical isolation in a high-power environment and soft switching within a wide load range. Aiming at the problem of sudden changes in voltage gain at a high switching frequency under light load conditions and the problem of insufficient voltage gain under heavy load conditions due to the parasitic parameters of power devices (mainly referring to the junction capacitor), this paper first proposes a full operating range performance optimization design method. By adding an auxiliary circuit that can be opened according to the operating conditions and a multi-objective particle swarm parameter optimization method that considers the converter loss and voltage gain under heavy load conditions, the performance of the LLC resonant converter can be improved in a full range of operating conditions. Finally, the effectiveness of the proposed method is verified by an experimental prototype and compared with the conventional methods and existing solutions to highlight the superiority of the proposed method in this paper.

Underwater Power Conversion and Junction Technology for Underwater Wireless Power Transfer Stations

“…Frequency Efficiency [20] LLC resonant / 380 V Nope 106 kHz / [21] Parallel resonant 450 W 120 V ZVS 250 kHz / [22] LCL-T resonant 500 W 150 V ZVS 250 kHz 96.0% [23] Parallel resonant 500 W 50~250 V ZVS 250 kHz 94.0% [24] DAB 500 W 150 V ZVS 250 kHz 95.0% [25] LLC To extend the application range with high efficiency and high power density, this paper presents a 1500 W power level undersea DC-DC converter with the LLC resonant circuit topology for the UWPT system. It could provide the load adaptive feature operating with the variable load resistance.…”

“…The target power level of a single node is 1.5 kW [19]. To improve the power conversion efficiency and reduce heat losses, there are different topologies that have been proposed, as shown in Table 1, such as the halfbridge LLC resonant circuit, LCL-T resonant DC-DC circuit, parallel resonant DC-DC circuit and dual active bridge (DAB) circuit [20][21][22][23][24][25]. Most topologies have a switching frequency exceeding 100 kHz to decrease the system size and improve the power density.…”

Enhanced Model Predictive Control for Induction Motor Drives in Marine Electric Power Propulsion System

“…Due to its high efficiency, energy conservation, excellent maintainability, and robust scalability, electric propulsion has become widely adopted as an advanced propulsion method in the realms of modern ships and underwater vehicles [1,2]. The marine electric propulsion system mainly employs AC motors to provide power drives, such as induction motors (IMs).…”