How the triple spool turbofan controls speed of each spool?

In a triple spool turbofan engine, each spool (high-pressure, intermediate-pressure, and low-pressure) operates at different speeds, allowing for optimized performance across a range of operating conditions. The engine's control system adjusts the fuel flow to each spool individually, which regulates their rotational speeds and ensures efficient thrust generation and fuel efficiency. Additionally, variable geometry components and bypass ratiOS can be employed to fine-tune airflow and pressure ratiOS between the spools, enhancing overall performance and responsiveness during various flight phases. This configuration allows for better control over thrust and improved engine efficiency.