Modelling and co-simulation of advanced control techniques for electric engines with real-time constraints

The increasing complexity of embedded software in modern cars, the transition to multi-core platforms and the introduction of safety-critical functions in automotive systems, are posing new problems to both control and software engineers. Developers need high levels of predictability, testability, and ultimately determinism in the execution of their code, while control engineers must be aware of possible delays and scheduling issues due to real-time events or sporadic overload conditions on undersized CPUs. Thus, the development of the control part of such applications cannot be separated from the timing analysis of the scheduling effects introduced by the computing platform in the execution of the code. Although classical control design methods and offline studies can help, they cannot be used to describe complex interactions between control and software timing in the design control phase. In order to fill this gap, this thesis presents a co-simulation environment aimed to take into account, simultaneously, the scheduling part, the control part and the physical components of an Internal Permanent Magnet Synchronous Motor (IPMSM) for an Electric Vehicle (EV). The co-simulation tool, entirely based on Simulink, comprehends a behavioural model of a CPU in order to manage, with a high timing precision, the entire task control chain for an IPMSM. In addition, also mechanical and electrical components of the system (e.g., IPMSM and the EV itself) have been included in the model. In this context, we address the control problem of an IPMSM for EVs, carry out a deep analysis of field weakening technique for IPMSM and present the development of an enhanced control scheme in order to improve the performance of the system. The model allows also a designer to test different intra-core communication and control paradigms, and see how they interact with the entire system. More in details, in this thesis we tested how the Logical Execution Time (LET) paradigm, which is used to increase predictability in multicores by trading jitter for latency, impacts the performance of control. On the other hand, we also tested the system performance when using the Periodic Event Triggered Control (PETC) paradigm, which can selectively “switch off” the control execution when its is not needed, in order to save computational and communication resources. Finally, an extensive set of experiments for a case study built with realistic data given by BOSCH is presented, in order to show the interactions presented in our work and prove the effectiveness of this approach. The performance of the system has been tested also in CPU overload conditions, looking for the sequence of scheduling delays that leads to the worst-case performance