Background and Requirements

Modern luxury yachts integrate an increasing number of electrical subsystems, ranging from navigation and safety equipment to comfort and auxiliary systems. These applications require reliable, efficient, and compact power conversion solutions that can operate in harsh conditions such as vibration, humidity, and wide temperature ranges.

For this project, a DC/DC power conversion solution was required to interface a high-voltage DC power domain with an isolated low-voltage onboard network. Key technical requirements included:

• Conversion of high-voltage DC input to an isolated 12 V or 24 V low-voltage output
• Support for both 12 V and 24 V battery configurations
• High efficiency to reduce energy losses and thermal stress (Up to 96%)
• Bi-directional power flow to enable advanced energy management concepts
• Ruggedised design suitable for harsh operating environments (marine adaptation without claiming marine certifications)
• Compact form factor for installation in space-constrained areas
• Reliable continuous operation at high power levels

The solution was developed for a low-volume serial production environment, with an estimated annual quantity of approximately 2-10 systems.

Technical Solution

To meet these requirements, the 800S24.4K0HBC DC/DC converter from the HBC800 series manufactured by Calex was selected as the key power conversion module.

The module is a liquid-cooled, galvanically isolated, bi-directional DC/DC converter with a nominal power rating of 4 kW. It converts high-side DC voltages in the range of 440 V to 875 V into an isolated low-voltage output (24 V nominal, depending on configuration and operating point). It also supports reverse power flow from the low-voltage side back to the high-voltage domain.

The converter is housed in a compact, thermally optimised enclosure with IP67 ingress protection, supporting robust operation in harsh environments.

System Integration and Benefits

Within the yacht’s electrical architecture, the DC/DC converter serves as the central interface between the high-voltage energy storage system and the 24 V onboard power network. The integrated CAN communication interface compliant with SAE J1939 allows monitoring, control, and diagnostics via the vessel’s power management system.

Key benefits of the implemented solution include:

• High energy efficiency combined with compact design
• Liquid cooling for stable thermal performance at high power density
• IP67-rated enclosure for harsh operating conditions
• Bi-directional operation supporting modern energy storage and charging strategies
• Galvanic isolation enhancing system safety and reliability