tailieunhanh - Finite control set model predictive control to balance DC-link capacitor voltage for TType NPC inverter of grid-connected photovoltaic systems
This paper proposes the Finite control set Model Predictive Control (FCS-MPC) with delay compensation for three-phase threelevel T-Type NPC inverter (T-Type NPC) of grid-connected photovoltaic systems (PV). The proposed FCS-MPC controls the objectives: current tracking control, DC-link capacitor voltage balance, the reduction of switching frequency to ensure issues of the power quality and improve the efficiency of grid-connected of PV system. | TAÏP CHÍ PHAÙT TRIEÅN KH&CN, TAÄP 18, SOÁ K6- 2015 Finite control set model predictive control to balance DC-link capacitor voltage for TType NPC inverter of grid-connected photovoltaic systems Phan Quoc Dzung Nguyen Dinh Tuyen Nguyen Minh Nhat Ho Chi Minh city University of Technology, VNU-HCM, Vietnam (Manuscript Received on July 15, 2015, Manuscript Revised August 30, 2015) ABSTRACT This paper proposes the Finite control set Model Predictive Control (FCS-MPC) with delay compensation for three-phase threelevel T-Type NPC inverter (T-Type NPC) of grid-connected photovoltaic systems (PV). The proposed FCS-MPC controls the objectives: current tracking control, DC-link capacitor voltage balance, the reduction of switching frequency to ensure issues of the power quality and improve the efficiency of grid-connected of PV system. The cost function of the proposed FCS-MPC uses the 27 possible switching states generated by TType NPC, the optimal switching state is selected in each sampling time that minimizes the cost function. The proposed FCS-MPC has also proposed the delay compensation with two-step prediction horizon at time k+2 to reduce the total harmonic distortion (THD) of the grid current. The proposed FCS-MPC is verified by using Matlab/Simulink. Keywords: Finite control set Model predictive control, reduction of switching frequency, DClink Capacitor voltage balance, T-Type NPC, PV system. 1. INTRODUCTION In the recent decades, photovoltaic system (PV system) quickly has been developed about the installed power, as well as the penetration into the electrical grid. Photovoltaic is the distributed generation, thus the stability when connecting the grid with the photovoltaic is a problem that worth to concern about at this moment. Due to the restrict of the two-level inverter is the output current with high THD distortion, the large size filters is chosen, however which causes some problems: reduction of the efficiency of PV system, high cost, bulky
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