Custom High-Frequency Transformers for Battery Energy Storage Systems

A European energy storage equipment manufacturer was developing a compact battery energy storage system for commercial applications. The power conversion system required a high-frequency transformer that could provide stable isolation and energy transfer while fitting into a limited internal space.

During prototype testing, the original transformer produced excessive temperature rise during continuous charging and discharging. The customer also observed switching noise and voltage spikes, which affected the stability of the power conversion stage. The existing transformer structure was difficult to optimize because the winding arrangement, core size, and thermal path had not been designed together.

Golden Eagle reviewed the customer's electrical schematic, switching frequency, power rating, turns ratio, insulation requirements, core structure, installation space, and cooling conditions. Instead of replacing the transformer with a standard model, the engineering team developed a custom magnetic design based on the actual PCS operating conditions.

The transformer winding structure was adjusted to control leakage inductance and reduce unnecessary switching loss. The core material was selected according to the operating frequency and expected thermal environment. The bobbin and terminal structure were also reviewed to ensure that the transformer could fit the PCB and maintain suitable creepage and clearance distances.

Thermal control was an important part of the development. The transformer was evaluated together with the PCB, enclosure, heat-dissipation path, and surrounding components. This helped the customer identify whether the heat came from the core, copper loss, switching conditions, or insufficient cooling around the component.

Golden Eagle supported prototype development through its 15 years of R&D experience. For suitable projects, the company can provide rapid samples within approximately 3–5 days, while the actual schedule depends on the specification, materials, tooling, and design iterations. Production quality is managed according to project inspection requirements, with the company stating a target defect rate below 0.5% for applicable production.

The customer evaluated the samples through turns-ratio testing, inductance measurement, leakage inductance, winding resistance, insulation resistance, Hi-Pot testing where applicable, temperature-rise testing, switching waveform observation, and long-duration charging and discharging. The customized transformer gave the customer a clearer basis for optimizing the PCS and reduced the risk of late-stage redesign.

For energy storage transformer sourcing, buyers should provide the input and output voltage, rated power, switching frequency, turns ratio, insulation requirements, target leakage inductance, core dimensions, PCB footprint, operating temperature, cooling method, sample quantity, and annual demand.

Golden Eagle supports OEM and ODM development for transformers, inductors, coils, and wireless charging products. Send the electrical schematic and mechanical drawing to receive an engineering feasibility review before finalizing the transformer structure.