Wind Converter Example¶

Variable-speed wind turbine power conversion system.

Overview¶

Modern wind turbines use variable-speed operation: - Maximum energy capture (MPPT) - Full power conversion (Type 4) - Grid code compliance - Fault ride-through capability

Specifications¶

Parameter	Value
Generator Type	PMSG
Rated Power	2 MW
Speed Range	8-20 RPM
Grid Connection	690V, 50 Hz
DC Link	1100V

Circuit Files¶

wind_pmsg_basic.ipes - PMSG with back-to-back converter
wind_dfig.ipes - Doubly-fed induction generator
wind_mppt.ipes - With tip speed ratio MPPT

System Architecture (Type 4 - Full Converter)¶

         Machine Side        Grid Side
┌───────┐  ┌─────────┐  ┌─────────┐  ┌──────┐
│ PMSG  │──│Rectifier│──│Inverter │──│ Grid │
└───────┘  └─────────┘  └─────────┘  └──────┘
    │           │            │
    └───────────┴────────────┘
                DC Link

Theory¶

Wind Power¶

\[P_{wind} = \frac{1}{2}\rho A v^3\]

Where: - ρ = air density (1.225 kg/m³) - A = swept area - v = wind speed

Power Coefficient¶

\[P_{turbine} = C_p(\lambda, \beta) \cdot P_{wind}\]

Maximum Cp ≈ 0.48 (Betz limit = 0.593)

Tip Speed Ratio¶

\[\lambda = \frac{\omega R}{v}\]

Optimal λ ≈ 6-8 for modern turbines

MPPT Strategy¶

Tip Speed Ratio Control¶

Wind Speed ──► λ_opt ──► ω_ref ──► Speed Control ──► Generator

Power Curve Control¶

Generator Speed ──► P_opt Curve ──► Torque Ref ──► Generator

\[P_{opt} = K_{opt} \cdot \omega^3\]

Grid-Side Control¶

Power Control¶

$$P^* = P_{turbine} - P_{losses}$$ $$Q^* = Q_{grid,ref}$$ (from grid operator)

Low Voltage Ride-Through (LVRT)¶

During grid faults: - Inject reactive current for voltage support - Limit active power - Maintain DC link voltage

DFIG Alternative¶

Doubly-Fed Induction Generator: - Reduced converter rating (30%) - Partial speed range (±30% of sync) - More complex control - Brush maintenance

Exercises¶

MPPT Implementation: Tip speed ratio tracking
Power Limiting: Pitch control above rated wind
LVRT: Simulate grid fault ride-through
Reactive Power: Grid voltage support