Supervisory Control System Development for a Toyota Mirai FCEV

The performance of a second-generation Toyota Mirai fuel cell was characterized as part of the SwRI internal research program. This data was used to develop a supervisory controller scheme designed to balance the plant for the fuel cell system during steady-state and transient vehicle conditions. This was accomplished using a Supervisory Integrated Controller (SIC) implemented on a Real-time Power Electronics Control System (RPECS) with a Simulink-based control algorithm. The actuators of interest are the three hydrogen injectors at anode inlet, air compressor and three air side valves on at the cathode inlet. The FC power measurement and pressure sensor readings at the anode and cathode were utilized as real-time feedback for the controller operation. The aim of the controller was to achieve and maintain the power target set by the hybrid powertrain ECU present on the vehicle, which is responsible for balancing power on the fuel cell and battery over the high-voltage bus. These actuators were initially calibrated using steady-state tests conducted at 25, 35, and 45 mph to characterize the OEM controller and calibration. Further calibration was performed using a high-fidelity plant model developed in GT-Suite. The SwRI controller closely tracked Toyota’s control signals during vehicle tests at various speeds and under regulatory test cycles. Transient data using HwFET, RMC, and FTP tests were used to validate the controller. The Southwest Research Institute (SwRI) controller managed key actuators, including hydrogen injectors and air-side valves, achieving control signal accuracy within 7% of existing OEM control scheme.