# A Novel Adaptive Model Predictive Control Based Three-Phase Inverter Current Control Method
## 4 Simulink Profile Report: Summary  
Figure 8: Comparison of simulation time between the proposed method and FCS-MPC based method (**a**) recorded time of the A-MPC based method, (**b**) recorded time of the FCS-MPC based method. Figure 7: Simulation results for the output current waveforms of the proposed A-MPC (**a**) current waveform for 0.04 s, (**b**) current THD. In order to analyze the performance of this MPC based control method under grid transients, a group of simulations are conducted on the condition of single-phase ground fault. The current of inverter are shown in Figure 9. It can be seen the amplitude of current changes during this period and its THD increases. Although the fault has negative effect on the power quality, the current is under control and return to stable state after the fault is eliminated. The performance of the proposed method is similar to that of other control method, such as PI control. In order to verify the effectiveness of the proposal in practical applications and compare the performances with other traditional control methods, a series of experiments are conducted in a microgrid laboratory, as shown in Figure 10. Parameters of the controlled inverter and other devices of the experimental system are shown as Table 1. The experimental result is collected by ScopeCorder DL850E, which combines a mixed oscilloscope and data acquisition recorder. In this way, the collected data can be inputted into a computer and processed. Figure 10: Microgrid laboratory. Figure 9: Current performance under single-phase ground fault (**a**) current waveform (**b**) THD of current within the fault period. Firstly, a group of experiments are conducted aiming to show validity of the model parameters modification process in the proposal. At the beginning the predicted parameters are given as \(L=0.8\) mH and \(R=3\)\(\Omega\), and reference RMS of output current is 10 A. The modification action is performed once every 0.1 s. Recorded output current during the modification process is shown in Figure 11a, while its RMS waveform is shown in Figure 11b, which is calculated by computer. It can be seen the accuracy of RMS of the output current is continuously improved with the modification. When the error between reference and collected current is less than the threshold, the modification is stopped, and will not be started until the error is larger than the threshold. In this system, the control frequency 6 kHz is relatively low because of the limit by the switching frequency of inverter. In order to verify the effectiveness of the proposed A-MPC based method in such a practical application, the steady state performance is analyzed. When the inverter is operated in a stable state, the current waveform and its THD are shown in Figure 12. The THD 4.70%, can satisfy the current harmonics requirement of IEEE standard IEEE1547 [26]. Figure 11: Experimental results for model parameters modification process of the proposed method (**a**) Current waveform, (**b**) current RMS waveform. Figure 12: Experimental results for steady-state current of the proposed A-MPC based method. To analyze dynamic performance of the proposal, another group of experiments is carried out. During the experiment, the reference current RMS changed from 5A to 10A at some moment. This test is carried out in order to compare the response speed and output current overshoot under step change. When the inverter is operated under PI control, the current waveform and its RMS waveform are presented in Figures 13a and 13b respectively  
When the inverter is operated under PR control, the step current waveform and its RMS waveform are presented in Figure 14a,b respectively. Figure 7:0 Experimental results for step current of PR control (**a**) real-time current waveform, (**b**) RMS current. Figure 7:1 Experimental results for step current of PI control (**a**) real-time current waveform, (**b**) RMS current. The response of the proposed A-MPC based control method to the same change is shown in Figure 15a,b.