Patent ID: 8496514

Claim:
A ventilation control system, comprising: suction and exhaust ducts having predetermined shape; a pre-filter disposed at an entry region of an inside of the suction duct; a first composite filter disposed next to the pre-filter and rotatably fixed at the inside of the suction duct; a second composite filter disposed next to the first composite filter and rotatably fixed at the inside of the suction duct; a fan motor disposed between the suction and exhaust ducts to linearly control an internal suction pressure in the suction duct in response to an external control signal; a first turning angle motor coupled to the first composite filter and controlling a turning angle of the first composite filter; a second turning angle motor coupled to the second composite filter and controlling a turning angle of the second composite filter; an outdoor air sensor for measuring freshness of outdoor air, converting the measured result into an electrical signal, and outputting the electrical signal; and a control unit for controlling the first and second turning angle motors and the fan motor, in order to control turning angles of the first and second composite filters and an internal pressure in the suction duct, wherein the control unit controls a rotational speed of the fan motor in inverse proportion to a sum of the turning angles of the first and second turning angle motors.