## 4 Results in Practical Cases
### Experimental Results
The source _ITHD_ values achieved in this work, as in the best of the Adaline or RNN works reviewed, are between 2% and 5%. The _PF_ reached in these cases is unity. The dynamical performance is as good as in many of the accepted control methods. Lastly, the UpfC control strategy corrects the problem of unbalanced currents, in the case of balanced source voltages. Table 3 shows a summary of some important features of different ANN-based control methods in the literature included as references in this paper. Figure 14: Supply source voltages and phase load current of the experimental three-phase laboratory setup. Up: source voltages showing some distortion and unbalance. Down: voltage and load current by one of the phases, where the current waveform is highly distorted. Figure 16: Experimental dynamic performance including load unbalance. At time labeled as \(t=0.02\) s, a change occurs from balanced to unbalanced load. Each graph shows one of the phases together with its respective source voltage. Figure 15: UpfC results at experimental practical case. Top graph: compensation current and voltage waveform for the same phase. Middle graph: source currents. Bottom graph: source current and voltage for the same phase, showing the power factor correction. In the comparison of some reference works showed in Table 3, it can be seen that most of the methods achieve an _ITHD_ value below 5%, recommended by the EN Standard [42]. Regarding the other features showed in the table, we can affirm that the method proposed in this paper reaches a complete set of requirements. In future works, this MLP-based control method must be further tested in the experimental platform with different loads and adverse conditions for an in-depth analysis of the performance. Besides, it is important to try to apply new deep learning techniques and other new ANN topologies, maintaining the control strategies and testing platforms for comparison. Figure 17: Experimental dynamic performance including load unbalance. Change at time \(t=0.02\) s. Top graph: compensation current and voltage waveform. Middle graph: source currents, showing balanced waveforms both before and after the load change. Bottom graph: source current and voltage, showing the power factor correction. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \begin{tabular}{c} **ANN Type,** \\ **Reference** \\ \end{tabular} & \begin{tabular}{c} **Applied** \\ **to APF** \\ \end{tabular} & \begin{tabular}{c} **Source ITHD** \\ **\textless{}5\%** \\ \end{tabular} & \begin{tabular}{c} **Power Factor** \\ **Compensation** \\ \end{tabular} & \begin{tabular}{c} **Balanced Source** \\ **Currents** \\ \end{tabular} & \begin{tabular}{c} **Experiment** \\ **Results** \\ \end{tabular} & \
\begin{tabular}{c} **Dynamical** \\ **Tests** \\ \end{tabular} &
\begin{tabular}{c} **Frequency** \\ **Deviations** \\ **Test** \\ \end{tabular} \\ \hline ADA [11] & ✓ & ✓ & ✗ & ✗ & ✓ & ✓ & ✗ \\ ADA [14] & ✓ & ✓ & ✗ & - & - & ✓ & ✓ \\ ADA [16] & ✓ & ✓ & ✓ & ✗ & ✓ & - & - \\ RBF [19] & ✓ & ✓ & ✗ & ✗ & ✓ & ✗ \\ RBF [20] & ✓ & ✓ & - & ✓ & ✗ & ✓ & ✗ \\ RNN [21] & ✓ & ✓ & ✗ & ✗ & ✗ & ✓ & - \\ RNN [22] & ✓ & ✓ & ✗ & ✗ & ✓ & ✓ & - \\ NARX [23] & ✓ & ✓ & ✓ & ✓ & ✗ & ✓ & ✓ \\ ESN [25] & ✓ & ✓ & ✓ & ✓ & ✓ & ✓ & ✗ \\ MLP [32] & ✗ & (1) & - & - & ✗ & ✗ & ✗ \\ MLP [33] & ✓ & ✗ & ✗ & ✗ & ✓ & - & - \\ This work & ✓ & ✓ & ✓ & ✓ (2) & ✓ & ✓ & ✓ \\ \hline \hline \end{tabular}  
* This method estimates a 4.4–6% _ITHD_ value for the waveform resulting of subtracting the harmonic waveform from the distorted load current, but without real compensation. (2) It works in the case of balanced supply voltages.  
\end{table} 
Table 3: Some features of the reference works, with control methods based on different ANN types.