Electric Ventilator For Hospital Use | Design Guide

This electric ventilator system is designed to provide mechanical breathing assistance through a combination of power electronics and electromechanical conversion. Power enters the system via an AC-to-AC cum DC power electronic converter, which utilizes a 3-winding step-down transformer to step down incoming voltages. IGBT bidirectional switches work within the conversion stages to control power flow, while a low-pass filter smooths out the electrical output to ensure stable operation. A potential divider is integrated to monitor and scale voltage levels accurately within the circuit. The conditioned DC power drives a Permanent Magnet DC (PMDC) Motor, which serves as the primary mechanical actuator. The rotational output of the PMDC motor is translated through a gear train and a rotating disc equipped with metallic links and a push rod. This mechanical linkage converts continuous rotational motion into the linear reciprocating motion necessary to actuate a plastic container or bagging mechanism. By rhythmically compressing and decompressing the bagging mechanism, the system delivers controlled volumes of air to support patient respiration. Prior to physical assembly, undergraduate engineering students can test and validate the power electronic circuit behavior using PC simulation software.