Active Pitch Control (APC) is a system that dynamically adjusts the angle (pitch) of wind turbine blades relative to the incoming wind.

By continuously optimising the blade angle, APC ensures the rotor operates at its most efficient aerodynamic condition across changing wind speeds, balancing three critical factors:

• Maximum energy capture

• Load reduction

• Structural safety

How APC Works in Wind Turbines

In large-scale wind turbines, Active Pitch Control is the industry standard for power regulation. The blades rotate around their longitudinal axis in real time, enabling the system to:

• Maximise power output at low to medium wind speeds

• Prevent aerodynamic stall

• Reduce structural loads during gusts

• Shut down safely in extreme wind conditions

APC in Small-Scale Wind Turbines

For small-scale turbines, active pitch control is far less common. Most micro turbines rely on:

• Fixed-pitch blades

• Mechanical stall systems

• Furling mechanisms

While these simpler systems reduce complexity, they limit performance and adaptability — especially in turbulent or urban environments where small turbines often operate.

Advantages in Built Environments

In variable and gusty wind conditions, Active Pitch Control provides significant benefits:

• Increased efficiency – Maintains optimal angle of attack across varying wind speeds

• Stall prevention – Avoids sudden aerodynamic performance loss

• Overspeed protection – Actively limits rotor speed in high winds

• Extended lifespan – Reduces mechanical stress and fatigue loads

By actively managing aerodynamic forces, APC enables small turbines to operate more intelligently and safely.

APC System Components

An Active Pitch Control system consists of three main components:

1. Sensors

Measure wind speed, rotor speed, and in some cases blade loading.

2. Controller

A control algorithm processes sensor data and determines the optimal blade angle in real time.

3. Actuators

Electric motors (or hydraulic systems) physically rotate the blades around their axis.

Our Approach at GEM

At GEM, integrating advanced control into small-scale wind systems allows us to bring large-turbine intelligence to distributed energy generation — improving performance, reliability, and long-term durability.