# 6.3 Predictive Current Control in an Active Front-End

The control scheme for the VOC of an AFE using predictive control for the current control loop is shown in Figure 6.4. A PI controller is used for DC link voltage regulation and generates the amplitude of the input current reference. The reference current is calculated by multiplying the output of the PI controller by the grid voltage waveform.

## 6.3.1 Cost Function

The predictive current controller must achieve the smallest current error with fast dynamics. An appropriate cost function is a measure of the predicted input current error. The following cost function considers the absolute error between the reference current and the predicted current, expressed in orthogonal coordinates:

6.16

where is the input current prediction at time *k* + 1 for a given converter voltage **v**_{afe}(*k*), and the current corresponds to the reference current at time *k*.

Results for the system shown in Figure 6.4 were obtained using the parameters shown in Table 6.1. Results at steady state and the behavior ...