Real-Time Control and Communication in Hybrid Vehicle Power Trains

The electrification of vehicles is advancing rapidly, with DC-DC converters playing a central role in their electrical architecture. Semiconductor technologies such as gallium nitride (GaN) MOSFETs enable high-power, high-temperature operation, enhancing vehicle performance. However, these advancements necessitate improvements in microcontrollers managing these components, including faster computation, advanced pulse-width modulation (PWM) signal generation, and real-time synchronization. This thesis analyses the AURIX TC39 microcontroller in order to develop software for managing a DC-DC converter in a hybrid vehicle architecture. This architecture comprises one inverter connected to the electric motor and two DC-DC converters, one of which interfaces with a battery and the other with a fuel cell. The research starts by implementing the Universal Asynchronous Receiver-Transmitter (UART) communication, which is crucial for the inverter to send reference currents to the DC-DC converters. The Direct Memory Access (DMA) is employed for the purpose of facilitating the efficient transfer of data within the system. To guarantee the reliability of the communication process, a synchronisation mechanism has been implemented to discard messages in the event of a transmission failure. This approach not only enhances the performance of the system by reducing the load on the CPU during data transfer operations, but also ensures the integrity and reliability of communications by preventing the propagation of corrupted or incomplete data. A further aspect of the communication system between the three microcontrollers is the use of Controller Area Network (CAN). This protocol is widely used in the automotive field due to its high degree of reliability. In the subsequent system, CAN is employed to facilitate the exchange of diagnostic, error and status messages between the electrical components within the architecture. In the following, the behaviour of the AURIX TC39 microcontroller in external input clock mode was analysed by studying its internal modules that deal with clock generation and distribution. The analysis that follows was carried out with a view to the future, as three AURIX TC39 micro controllers are expected to share the same clock source to optimise their synchronisation. Furthermore, the Generic Timer Module (GTM) is employed for the generation of PWM signals and the determination of sampling instants in order to manage the switching poles of the DC-DC converter. This is achieved using the Timer Output Module (TOM). To improve the correct behaviour of the components inside the electrical architecture, the counters responsible for generating the PWM signals are synchronised to the inverter component by means of a reset signal. The implementation of dead time and the optimization of synchronisation between microcontrollers are achieved through the use of the Dead Time Module (DTM) and Timer Input Module (TIM). As a result, the Generic Timer Module (GTM) within the AURIX TC39 has proven to be an optimal component for the developed applications, offering high-speed signal generation and synchronisation features to enhance the behaviour of the system in automotive applications. Finally, the developed control algorithm was tested on the microcontroller to verify compliance with the execution time constraints imposed by the requirements, thus ensuring efficient management of the DC-DC converter within the electrical system of the vehicle.