Direct power control based on point of common coupling voltage modulation for grid-tied AC microgrid PV inverter
Document Type
Article
Publication Date
1-1-2022
Abstract
In this paper, a direct power control (DPC) approach is proposed for grid-tied AC MG's photovoltaic (PV) voltage source inverter (VSI) to regulate directly active and reactive powers by modulating microgrid's (MG) point of common coupling (PCC) voltage. The proposed PCC voltage modulated (PVM) theory-based DPC method (PVMT-DPC) is composed of nonlinear PVM, nonlinear damping, conventional feedforward, and feedback PI controllers. For grid synchronization rather than employing phase-locked-loop (PLL) technology, in this study, direct power calculation of the PCC voltage and current is adopted. Subsequently, at PCC, the computed real and reactive powers are compared with reference powers in order to generate the VSI's control signals using sinusoidal pulse width modulation (SPWM). Because of the absence of the PLL and DPC method adoption, the suggested controller has a faster convergence rate compared to traditional VSI power controllers. Additionally, it displays nearly zero steady-state power oscillations, which assures that MG's power quality is improved significantly. To validate the proposed PVMT-DPC method's performance real-time simulations are conducted via a real-time digital simulator (RTDS) for a variety of cases. The results demonstrate that PV VSI using the suggested PVMT-DPC approach can track the reference power quicker (0.055 s) along with very low steady-state power oscillations, and lower total harmonic distortion (THD) of 1.697% at VSI output current.
Keywords
Phase locked loops, Voltage control, Power control, Reactive power, Real-time systems, Microgrids, Mathematical models, Power grids, Power quality, Voltage-source converters, Direct power control, grid-tied, microgrid, PLL, power quality, RTDS, voltage source inverter control
Divisions
fac_eng
Funders
University of Vaasa under the Centralized Intelligent and Resilient Protection Schemes for Future Grids Applying 5G (CIRP-5G) research project - Business Finland [6937/31/2021],Business Finland [6844/31/2018]
Publication Title
IEEE Access
Volume
10
Publisher
Institute of Electrical and Electronics Engineers
Publisher Location
445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA