Compared to conventional charging solutions, the virtually isolated Onboard Charger does not require a transformer for galvanic separation (isolation) between the AC grid and the DC vehicle system as a result of innovative software and hardware design
03 Sep 2025 | 26148 Views | By Ajit Dalvi
The purely virtual insulation reduces the installation space and volume of the onboard charger by up to half and its weight by around a third. (Image: Forvia Hella & Tau)
International automotive supplier Forvia Hella and Tau Motors, a pioneer in software-defined power conversion, are working on advanced charging ...
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The purely virtual insulation reduces the installation space and volume of the onboard charger by up to half and its weight by around a third. (Image: Forvia Hella & Tau)
International automotive supplier Forvia Hella and Tau Motors, a pioneer in software-defined power conversion, are working on advanced charging solutions in the context of a strategic development cooperation.
The focus is on the development of a ‘virtually isolated Onboard Charger (viOBC)’ for electric vehicles, aiming to bring it into series production within the next two to three years. By dispensing with a transformer, the viOBC has a high-power density and energy efficiency on the one hand; on the other, the weight and required installation space can be significantly reduced. The product also enables advanced energy management in vehicles, including vehicle-to-grid integration with bidirectional charging. The development partnership also includes an investment in Tau via the venture capital arm Hella Ventures.
In this partnership, Forvia Hella contributes extensive expertise in the field of high-voltage and power electronics as well as industrialization capabilities. Tau brings its software-defined technology platform alongside deep expertise in power electronics, controls, and innovative product design capability to the table.
"We are very pleased with the partnership with Tau and the joint development of this outstanding Onboard Charger with an exceptionally high degree of innovation. The collaboration takes onboard charging to the next level and creates a product that sets new standards in power density. With this, we are also expanding our portfolio of high-performance key components for electrification. viOBCs represent another significant contribution to sustainable mobility and strengthens our position as an innovation leader," said Jörg Weisgerber, Managing Director Electronics at Forvia Hella.
Wesley Pennington, Founder and CEO of Tau, added: "This advanced technology partnership brings together Tau’s software-defined power conversion platform and Forvia Hella’s global scale in product, quality, and safety. More importantly it aligns groundbreaking technology with industrial excellence to deliver the next generation of high-voltage power electronic and energy management solutions for clean, intelligent mobility."
Transformer-less design
Compared to conventional charging solutions, the virtually isolated Onboard Charger requires no transformer for galvanic separation (isolation) between the AC grid and the DC vehicle system thanks to innovative software and hardware design. Despite this, it fully ensures electrical and functional safety while maintaining the range of functions found in transformer-based designs. By eliminating the transformer, the viOBC achieves a very high-power density of up to 7 kW per litre of installation volume. The virtual isolation technology enables the space requirements and volume for vehicle’s OBC to be reduced by up to half, and its weight by around a third.
Moreover, the transformer-less design enables an energy efficiency of more than 98 percent during the charging process. This subsequently enables CO2 savings through weight reduction as well as lower electricity costs due to higher efficiency. A viOBC prototype has now successfully completed its technological and commercial concept testing; series production is expected to begin within the next two to three years.