Numerical integration of ODEs in real time systems like state observers: stability aspects

This paper deals with the performance of some numerical integration (NI) methods for ordinary differential equations in real-time applications involving stiffness. After summarizing the main results about accuracy and stability of some well-known schemes, the point of view of the control is emphasized, by showing the impact of the NI on the dynamics of the discretized model. Moreover, some peculiarities of the NI in hybrid systems are touched by introducing a simple hybrid model for testing the performances of some NI schemes. Finally, some experimental tests are shown, dealing with a control of a sensorless drive whose model is characterized by stiffness.