Power factor regulators for heating applications

International standards limits concerning current harmonics and voltage fluctuation sometimes are not satisfied by phase and on-off controllers of electric and electronic household appliances. Many of these appliances behave like a resistive load. This article analyzes the use of power factor regulators when feeding this kind of load. In these applications, the variable to be controlled is the average output power. Suitable topologies for step-down operation are considered. The behaviors in continuous and discontinuous operation modes are analyzed. Design criteria are presented. Experimental results are reported for the selected topologies