**6. Discussion**

From the real-time simulation results, it can be realized that the proposed PLL-less PVMT-based FLDPC method is capable of controlling the real and reactive power, irrespective of the load variability and solar irradiation variations. For different power references, it was observed that the PV-VSI output real power controlled by the proposed PVMT-based FLDPC was tracking the reference real and reactive powers accurately. On the other hand, though the conventional dq CCS-based power controller was also tracking the reference powers, the tracking speed of the proposed PLL-less PVMT-based FLDPC method was found to be faster than that of the conventional dq CCS-based power control method, because the proposed power control method PLL system and park transformation was omitted and the PCC voltage modulated the DPC method. Moreover, in the feedback controller, FLC was applied to minimize the errors between the reference powers and VSI output power, to ensure PV-VSI output powers were following the reference powers accurately.

Similar to the tracking performance the proposed PLL-less PVMT-based FLDPC method exhibited excellent performance during a steady-state. The proposed PVMT-based FLDPC overcame the steady-state oscillations issue, due to acquirement of an exponentially stable decoupled linear time invariant error dynamic by the proposed controller. It was observed that for the proposed PVMT-based FLDPC, there was very low ripple in the VSI real and reactive power output. However, there was higher ripple observed in the VSI power outputs for the conventional PLL-based power controller, and powers were also not following the reference accurately.

From the results presented in Table 2, it can be seen that the proposed controller also performed as outstanding while transferring power among different sources of MG, grid and load during MG's grid-tied, and islanding operating modes. From the real time simulation results, it was observed that during grid-tied mode the proposed PVMT-DPC method performed excellently by maintaining the required power flow between the MG and grid, as the PV system was capable of providing the power according to the solar irradiation changes. In addition, during the transition from grid-connected to islanded mode, the proposed PVMT-DPC method also showed a robust performance. Finally, from the comparison results presented in Table 3, it was observed that the proposed PLL-less PVMT-based FLDPC method integrated PV-VSI showed a better performance during both

the transient-state and the steady-state compared with the conventional power controllerintegrated PV-VSIs connected to AC-MGs.
