Infineon SiC technology improves efficiency in Fox ESS energy storage systems
Infineon supplies silicon carbide (SiC) power semiconductors to Fox ESS to enhance the efficiency of its residential energy storage systems (ESS). Leveraging Infineon’s CoolSiC MOSFETs 1200 V G2 in the Q-DPAK package, Fox ESS has reduced switching losses by 70 percent. As a result, the company’s PQ3-Ultra energy storage system achieves a peak photovoltaic (PV) inverter efficiency of up to 98.78 percent in grid-tied operation and a peak battery charge/discharge efficiency of up to 98.47 percent.
Within Fox ESS’s energy storage system, Infineon’s CoolSiC MOSFETs 1200 V G2 in the top-side-cooled Q-DPAK package deliver optimised thermal performance, system efficiency and power density. The devices are specifically designed for demanding applications requiring high performance and reliability. Featuring Infineon’s advanced .XT interconnection technology, they reduce thermal resistance and operating junction temperature, while the trench gate architecture helps lower switching losses. Compared with conventional bottom-side-cooled designs, the Q-DPAK package supports improved PCB layout, helping to reduce parasitic effects and stray inductance while enabling superior thermal management. Its compact footprint supports space-saving system designs, while compatibility with automated assembly simplifies cost-efficient, scalable manufacturing.
For its hybrid ESS solution combining the PQ-H3-Ultra-10.0 inverter with the EQ3300-5 battery, Fox ESS has achieved a System Performance Index (SPI) of 97.0 percent in a recent test by HTW Berlin University of Applied Sciences and AQUU Research. This ranks Fox ESS first in the 10 kW class among all hybrid inverter and storage systems tested in 2026 and marks the highest SPI score recorded since the evaluation was launched in 2018. Over the past three years, Fox ESS has installed more than 890,000 PV inverters and over 1 million batteries in more than 70 countries.
