Graded frequency control strategy and numerical simulation of mine local ventilator

At present, most coal mines in China do not have advanced ventilation systems, and local ventilation fans usually use constant frequency operation “one wind”to discharge gas, resulting in low equipment efficiency and serious waste of resources and energy. In view of the above problems, taking a mine as an example, the relationship between gas volume fraction and air demand in roadway was deeply analyzed, and a graded frequency conversion control strategy was proposed, which divided the fan frequency into four levels. The operating conditions of the system frequency upturn and frequency downturn were formulated by combining the fuzzy control theory. The fan control and gas emission under different gas volume fraction conditions were analyzed by numerical simulation method. The results show that this control strategy can keep the gas volume fraction in the working face within the range of 0.5%-0.8%, without complicated decoupling calculation, improve the stability of the system operation to a certain extent, realize “on-demand ventilation” in a real sense, which significantly improves ventilation efficiency and reduces energy consumption.