Development of Boost Converter for MIRAI

Abstract

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).

Modeling of Fuel Cell Hybrid Vehicle in Modelica: Architecture and Drive Cycle Simulation

“…The hybrid drivetrain is constructed in a similar configuration to Toyota Mirai [11]: both the fuel cell and the battery are connected to DC/DC converters to match the maximum motor voltage. While Mirai has an AC motor and an inverter, the Modelica model uses a DC motor model because the high-frequency dynamics are not of interest in this study.…”

Impact of Low Frequency Narrow Pulse Current on the Degradation of Proton Exchange Membrane Fuel Cells

“…The multiple‐phases DC/DC converter can significantly reduce the fuel cell current ripple , and the relationship among power, efficiency and drive phase number is obtained by comparing experimental data, as shown in Figure . Under the condition that current ripple meets requirements, single phase operation is required in a certain power range in order to optimize the operational efficiency of DC/DC converter, but continuous operation of a single phase can cause over‐temperature of inductor and IGBT, thus the commutation operation is vital.…”

Efficiency-optimal power partitioning for improved partial load efficiency of electric drives

“…Toyota uses this strategy to manage a 114 kW boost converter implemented in the hydrogenpowered Mirai fuel cell electric vehicle (EV) [28]. The DC converter regulating the voltage delivered by the fuel cell is made of 4 parallel legs.…”

“…The DC converter regulating the voltage delivered by the fuel cell is made of 4 parallel legs. The associated control determines in realtime the optimal number of cells to be used; this strategy leads to reduce the boost losses by ten per cent at 15 kW operating point [28]. This design also induces significant system improvements [25]: among the benefits, one could easily identify input and output current ripple reduction [29], a better continuity of service and also a fast transient response if using multiphase interleaved dcdc converters, as in the case of the power management of microprocessors or double-data rate Accepted article for publication in a future issue of ELSEVIER Electric Power Systems Research -Citation information: 10.1016/j.epsr.2016.09.014.…”