A novel ventilation control strategy with piston effect for optimal management in a subway station

In this paper, we develop a novel approach for electrical daily management of subway station ventilation applied
to a microgrid. Piston effect caused by the train air pressure is modelled. It is integrated into the control strategy
in order to improve the motor speed’s dynamic characteristics. The air flow control is emulated on a laboratory
experimental test bench.
The main purpose of the paper is the speed control of the ventilation by considering different external data (Air
quality, temperature…) and without reducing the equipment lifetime. For achieving it, two control strategies are
necessary: High-level control and Low-level control.
The high-level control is an airflow input control considering external data, this input is converted into rotational
speed according to the fan characteristics. The motor speed is controlled in function of this input.
The low-level control takes back the high level-control in order to improve the motor dynamics for high
frequency.
A piston effect, due to the forced-air flow inside a tunnel or shaft caused by moving trains, disturbs the
ventilation control. The piston effect is seen like a resistive torque by the system and is taken into account in the
high-level control strategy. The air flow control dynamic is reproduced on a laboratory test bench at reduced
scale.