Reducing the size, weight, and cost of components is a critical part of the widespread adoption of fuel cell vehicles (FCVs).
The new FCV, “MIRAI” developed by Toyota Motor Corporation (TMC) features a compact fuel cell (FC) and shares the power control unit (PCU), motor, and battery adopted on mass-production hybrid vehicles (HVs). It also incorporates a newly developed boost converter that steps up the voltage from the FC, called the FC DC-DC converter (FDC).
The role of FDC is to pass the high power generated by the FC to the motor. Because of the high power requirement, a major challenge was developing countermeasures to limit component size. This was achieved by adopting a multi-phase converter and an innovative cooling structure.
Several other refinements were made to FDC, including enabling highly efficient drive by optimizing the number of drive phases in accordance with the load and randomly varying the switching frequency to reduce noise and vibration (NV).
This paper describes the technologies adopted by FDC installed in the MIRAI.