According to their press release, current hybrids without such a device have to compromise the energy storage device (batteries or ultra-capacitors) and the motor. When using regenerative braking, the motor charges the batteries while it slows down but there comes a moment when the power supplied by the slowing motor cannot charge the batteries any further, losing some additional recharging energy. The same happens when the car accelerates: the batteries supply power until the speed of the motor is so high that they cannot supply any more.
The consortium claims the DC-DC converter fixes this situation by boosting or reducing voltage so less energy is lost in the charge/discharge process. The announced converter is designed for 50 kW systems (67 HP), which allows for smaller gas engines or the substitution of turbos or superchargers in performance cars.
Current issues for the product's development are making the system capable of shutting down in case of failure and adding a "limp home" (reduced power) mode, two requisites from the auto industry.