Intelligent circuit breaker using thermoelectric hybrid overload protection

A three-dimensional finite element model of miniature circuit breaker is established. The steady state temperature field is obtained by the method of electrothermal coupling, and the mechanism of overload protection is analyzed. The influence of wire size on the temperature of bimetal is studied. A simple and effective method to reduce the influence of external wire size is presented. The influence of ambient temperature on temperature rise of bimetal is studied. A new heating element which is used to detect the temperature is proposed, and it is insensitive to the ambient temperature. The current is measured by calculating the slope of the temperature curve. In the future, the device action or not will be judged by detected current instead of the existing method. Simulation shows that the accuracy can meet the requirements of overload protection. The research is helpful for the follow-up study on the intelligent of miniature circuit breaker.