METHOD AND DEVICE FOR CONTROLLING THE TEMPERATURE OF AN ELECTRIC HEATER THAT FUNCTIONS WITH A POSITIVE TEMPERATURE COEFFICIENT (PTC) HEATING ELEMENT

摘要

The invention relates to a method for stabilizing the temperature of an electric heater, particularly a motor vehicle auxiliary heater, that functions with a positive temperature coefficient (PTC) heating element. The aim of the invention is to stabilize the temperature at a set value, which is less than the temperature at which the PTC heating element would stabilize itself in the existence of a predetermined nominal voltage of a voltage source, by controlling the current by: determining, as an actual value, the intensity of the current flowing through the PTC heating element at the moment; comparing the actual value with a set value of the current intensity which, in the selected PTC heating element, is determined by the selected set temperature, and; controlling, as a set variable, the voltage applied to the PTC heating element in the temporal mean according to the deviation of the actual value from the set value of the current intensity.