Power supply control system for heater used in gas sensor

摘要

A heater power supply control system is provided for controlling the temperature of a heater used to heat a solid electrolyte-made sensor element of a gas concentration sensor up to a desired activation temperature. The heater power supply control system measures a resistance value of the sensor element and controls an electric power supply to the heater using a PI control function. The heater power supply control system works to limit the value of an integral term of the PI control function in the course of activation of the sensor element, thereby avoiding overshoot of the resistance value of the sensor element, which avoids thermal damage of the sensor element.