Predictive Control of Power Converters and Electrical Drives

3.1 Predictive Control Methods for Power Converters and Drives

Predictive control covers a very wide class of controllers that have found rather recent application in power converters. A classification for different predictive control methods is shown in Figure 3.1, as proposed in [1].

Figure 3.1 Classification of predictive control methods used in power electronics (Cortes et al., 2008 © IEEE)

The main characteristic of predictive control is the use of a model of the system for predicting the future behavior of the controlled variables. This information is used by the controller to obtain the optimal actuation, according to a predefined optimization criterion.

The optimization criterion in hysteresis-based predictive control is to keep the controlled variable within the boundaries of a hysteresis area [2], while in trajectory-based control the variables are forced to follow a predefined trajectory [3]. In deadbeat control, the optimal actuation is the one that makes the error equal to zero in the next sampling instant [4, 5]. A more flexible criterion is used in model predictive control (MPC), expressed as a cost function to be minimized [6].

The difference between these groups of controllers is that deadbeat control and MPC with continuous control set need a modulator in order to generate the required voltage. This will result in having a fixed switching frequency. The other ...