Mapping of Continuous‐Time Models to Discrete‐Time Models

This chapter discusses how continuous time (CT) and discrete time (DT) are two alternative frameworks that are used in the modeling of variables. Generator‐ and grid‐side currents are regulated and fed into the grid in a controlled manner by properly regulating the turn‐on and turn‐off statuses of the switching devices in the power converter. The objective of discretization methods is to minimize the discretization error to an acceptable minimum value and to involve simple discrete mathematical expressions and calculations. Exact discretization methods are further classified into pole‐zero matching methods and invariant approaches, which include impulse invariant, step invariant (ZOH), and ramp invariant methods. Discretization methods are selected according to the specific application and nature of control variables. The forward and backward Euler methods provide implicit and explicit solutions, respectively. The combination of these two methods obtains a better solution in DT. The bilinear transformation is also known as the Tustin or trapezoidal method.