Grid and Solar PV Based Water Pumping using an Induction Motor
Grid System Overview
The grid system component of the setup integrates single-phase grid electricity with an amplitude of 325V (equivalent to 230V RMS). Here's a breakdown of its components and functionality:
Voltage and Current Measurement: The system begins with measuring the voltage and current of the grid side.
Diode Rectifier: Converts AC from the grid into DC.
LC Filter: Smooths out the ripple in the rectifier's output.
Boost Converter: Used for power factor correction to ensure the grid-side current remains sinusoidal, improving overall system efficiency.
Phase Lock Loop (PLL): Generates a unit vector template to maintain phase angle with respect to time, crucial for maintaining sinusoidal currents.
Reference Current Generation: A control logic generates reference currents, which when multiplied with the unit vector template, rectifies the output waveform to achieve sinusoidal grid currents.
Solar PV System Overview
The solar PV component harnesses renewable energy from the sun to supplement or replace grid power based on availability:
Solar Panel Specifications: Panels rated at 210 watts, with a maximum power point of 28.7V and 1.32A.
Boost Converter with MPPT: Uses Incremental Conductance Maximum Power Point Tracking (MPPT) to optimize power extraction from the solar panels.
Integration with Grid System: Outputs from the solar PV and grid systems are combined to power the induction motor.
Induction Motor and Water Pump Operation
The heart of the system is the three-phase induction motor used for water pumping:
Motor Specifications: Operates at 2.2 kW, with speed and torque controlled based on the system's operational mode.
Inverter Operation Modes:
Mode 1: Operates solely on solar PV power.
Mode 2: Relies solely on grid power.
Mode 3: Utilizes power from both grid and solar PV based on availability.
Speed Control: Achieved through a closed-loop control system using feedback from the motor's speed.
Simulation and Results
The system's performance under different conditions such as varying irradiation levels and operational modes is simulated and analyzed:
Mode 1 Simulation: Demonstrates operation solely on solar PV power.
Mode 2 Simulation: Shows operation using grid power exclusively.
Mode 3 Simulation: Illustrates power sharing between grid and solar PV based on irradiation levels.
Conclusion
The grid interface to solar PV-based water pumping system offers a sustainable solution for providing reliable water pumping capabilities. By intelligently combining grid electricity with solar power, the system optimizes energy use while ensuring consistent operation of the induction motor-driven water pump.
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