Three Phase Grid-connected PV wind system

Exploring a Three-Phase Hybrid PV Wind System

We're diving into the intricacies of a three-phase hybrid PV wind system, as demonstrated through our developed Simulink model. This model represents a system integrating both solar and wind power sources with a main electrical grid.

System Overview

Main Grid:

• Power Rating: 154 MW

• Voltage Rating: 34.5 kV

Step-Down Transformer:

• Steps down from 34.5 kV to 400 V

Loads:

• Load 1: 12.5 kW

• Load 2: 17.5 kW

• Operating Voltage: 400 V (Line-to-Line)

• Frequency: 50 Hz

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Solar PV System

Solar Panel:

• Rating: 45 kW

• Grid-Side Voltage: 400 V

• Frequency: 50 Hz

The PV panel is connected to the grid inverter via a DC link capacitor. The inverter control involves measuring grid voltage and current post harmonic filter, and PV panel voltage and current to apply the Perturb and Observe (P&O) Maximum Power Point Tracking (MPPT) algorithm.

Wind Energy System

Doubly-Fed Induction Generator (DFIG):

• Control: Rotor side control to manage power extraction under varying wind speeds. The rotor is connected to the grid through an AC-DC-AC converter system.

• Frequency: Rotor frequency is typically less than 50 Hz.

Simulation and Control

Inverter Control:

• Involves converting grid-side measurements (voltage and current) into a DQ reference frame.

• Generates control signals through a PI controller, modulating the neutral-clamped inverter to synchronize with the grid.

Wind Turbine Control:

• Employs similar DQ control for both rotor and grid sides.

• Uses AC-DC-AC conversion to match grid frequency.

Simulation Results

The simulation runs for four seconds with specific conditions:

1. Initial Condition: Solar irradiation at 1000 W/m².

2. After 2 Seconds: Solar irradiation drops to 800 W/m².

Observations:

• Grid Power: Initially, the system feeds excess power to the grid due to high PV generation.

• PV Power: Drops when irradiation reduces, causing a decrease in excess power fed to the grid.

• Wind Power: Adjusts based on wind speed changes from 12 m/s to 9 m/s, showing a gradual decrease in power output.

Key Takeaways

1. Power Management: The hybrid system efficiently manages power generation and distribution, adjusting to changes in solar irradiation and wind speed.

2. Grid Interaction: Excess power generated by the PV and wind systems is fed back to the grid, demonstrating effective integration.

3. Control Systems: Both PV and wind systems use sophisticated control mechanisms to ensure stable and optimal power delivery.