Development of Flexible System Controllers for Fuel Cell Control Systems

Kurzfassung

This master thesis is part of the development of a highly modular and adaptable distributed control system. It aims at developing a flexible system controller made of a standard main board and a functionally oriented auxiliary board. The main board is developed to provide the ability to connect and to instruct any auxiliary board for the execution of its intended functionality. The desired functionality of the auxiliary board is offered via the I/O Interfaces implemented on it. Each system controller is designed to perform network communication with an unspecified number of other controllers forming a distributed control system, e.g. a fuel cell control system. The system controller is practically referred to as the control board. The main board is designed to serve as a standard computer platform for any auxiliary board. It is tasked to perform network communication with other nodes, compute the control algorithms and instruct the auxiliary board for the execution of the control instructions. The auxiliary board is tasked to internally communicate with the main board, execute the control instructions it receives and provide the necessary outcome of the execution to the main board. To achieve its functional objective, the main board is designed as a mini-computer capable of running an embedded Linux operating system. It is developed with an ARM926 embedded microprocessor unit, an external memory, network communication integrated circuits, a power supply circuit and I/Os. The auxiliary board is developed with a microcontroller and with some sensors and actuators that are used to implement the I/O interfaces. The flexibility of the control board is provided through two network communication interfaces namely CAN-Bus and Ethernet and three internal serial communication interfaces namely SPI, I2C and UART. In this sense, the control board can be integrated in a distributed control system having CAN-Bus or Ethernet as the communication network. The main board can accommodate any auxiliary board as long as one of the above mentioned serial interfaces is available on the auxiliary board. The control board is implemented with a defined form factor for both the main board and the auxiliary board. The electrical requirements of the control board are fulfilled and the functional requirements are tested. The basic functional requirements of the control board are fulfilled with Arch Linux as the embedded Linux operating system, and Ethernet and UART as the network and the internal communication interfaces respectively. The I/O interfaces are simply implemented on the auxiliary board with an environmental sensor and a current sensor and with LEDs serving as actuators. Rudimentary software is developed on both the main board and the auxiliary board to test and demonstrate the basic functionality of the system controller. Even though this system controller is not to be certified or to be considered as a final product, the first step towards the development of a much more complex system controller is achieved.