On preserving passivity in sampled-data linear systems by using state observers

Passivity is a well known phenomenon. Due to its interesting properties, it is widely used in several areas of control engineering. In general, passivity is lost under direct discretization. In this work, a new methodology which allows to preserve continuous-time passivity is revisited. This methodology is based on choosing a proper output which preserves the passivity structure, while keeping the continuous-time energy function. As this new output needs information about the system state, an state observer is added.