Solar energy is one of the most promising Renewable Energy Sources (RES) that can produce electric energy through Photovoltaic (PV) process. The Solar Photovoltaic (SPV) systems which directly supply power to the grid are becoming more popular. A power electronic converter which converts DC power from the PV array to AC power at required voltage and frequency levels is known as Inverter. Different Pulse Width Modulation (PWM) techniques have been implemented for grid connected 3-phase Voltage Source Inverter (VSI) system. This paper describes few types of PWM techniques and mathematical model of LC filter circuit is given using state space analysis. Sine-PWM technique is proposed for 3-phase VSI and implemented using the state space model of the LC filter circuit. We performed the simulation in MATLAB/Simulink platform. They presented simulation results for the inverter and load side to show the satisfactory performance of the sine-PWM technique.
Pulse width modulation
Voltage source inverter
Fig. 1. General Block Diagram of Grid Connected SPV system
EXPECTED SIMULATION RESULTS:
Fig. 2. Carrier wave (Vtri) and Modulating wave (Vsin)
Fig. 3. Inverter Output line to line Voltages (ViAB,ViBC,ViCA)
Fig. 4. Inverter Output Currents (iiA,iiB,iiC)
Fig. 5. Load line to line voltages (VLAB, VLBC, VLCA)
Fig. 6. Load Phase Currents (iLA,iLB,iLC)
Fig. 7. Inverter output line voltage, Inverter output current, Load line
voltage, Load phase currents
Increasing demand on energy efficiency and power quality issues, grid connected solar PV systems is taking a good place. In this paper we have discussed SPWM and SVPWM techniques for 3-phase grid connected VSI. We use the LC filter circuit in the proposed system. This filter circuit is mathematically modeled by using state space analysis and complete state space equation is obtained. The SPWM technique is implemented and simulated on 3 phases VSI using state space model of the LC filter circuit for grid connected solar PV system. Various simulation results are analyzed and presented on the inverter and load side of the proposed system in order to show the satisfactory performance of sine-PWM technique for grid connected solar PV system.
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