Fractional order PI controlled Grid Connected PV System
Introduction
Welcome to LMS Solutions! In this session, we will delve into the intricacies of a fractional order PI (Proportional-Integral) controlled connected PV system. Specifically, we'll compare it with a conventional PI controlled connected PV system. The primary focus will be on the utilization of a fractional order PI controller in the voltage control element block.
PV System Overview
Photovoltaic Panel Details
Single panel output: 13 watts
Maximum Power Point Voltage: 29 volts
Maximum Power Point Current: 7.35 amps
System Configuration: 10 series panels and 5 parallel strings
Maximum Power Output: 10.66 kilowatts at 1000 W/m²
Boost Converter and MPPT Algorithm
Voltage Boost: From 290 volts to 700 volts
MPPT Algorithm: BNBPD (Boost-Negative Boost Perturb and Observe)
Three-Phase Inverter and Control
Inverter Control: Feed-forward EQ control
DC Link Voltage: Controlled using Fractional PID Controller
PI Controller Parameters: ��=0.1,��=0.01,�=1.5,�=0.5Kp=0.1,Kd=0.01,λ=1.5,μ=0.5
Simulation and Results
Irradiation Conditions
400 W/m²
800 W/m²
600 W/m²
Fractional Order PI Controller Results
PV Power:
400 W/m²: 4307 watts (Theoretical: 4313 watts)
800 W/m²: 8589 watts (Theoretical: 8589 watts)
600 W/m²: 6468 watts (Theoretical: 6475 watts)
Grid Current:
400 W/m²: 10 amps peak
800 W/m²: 16-17 amps peak
600 W/m²: ~14-15 amps peak
THD of Grid Current:
<1%
Conventional PI Controller Results
PV Power:
400 W/m²: 4292 watts (Theoretical: 4313 watts)
800 W/m²: 8579 watts (Theoretical: 8589 watts)
600 W/m²: 6463 watts (Theoretical: 6475 watts)
Grid Current:
400 W/m²: ~10 amps peak
800 W/m²: ~16-17 amps peak
600 W/m²: ~14-15 amps peak
THD of Grid Current:
~4% - 5%
Analysis and Conclusion
Comparing the two control strategies, the fractional order PI controller demonstrates superior performance in terms of PV power extraction and grid current quality. The THD of grid current is significantly lower with the fractional order controller, ensuring a more efficient and cleaner power transfer to the grid.
In conclusion, the fractional order PI controlled connected PV system outperforms the conventional PA controller in terms of power extraction and grid current quality. This innovative approach presents a promising avenue for enhancing the efficiency and reliability of grid-connected photovoltaic systems.