Output Estimation Method by Resonant Current Measurement for Filament Power Supply

This paper proposes a method for estimating the output voltage and current by measuring the low-voltage side resonant current of a series resonant converter operating in discontinuous conduction mode(DCM) for filament power supply applications. The proposed estimation method does not require sensing on the output side, so the high voltage insulation problem of the filament power supply sensing circuit in which the output is connected to the high voltage terminal of several tens of kV is solved. Through operation mode analysis, a resonant current equation for each mode was derived, and a method was derived to estimate the output voltage and current using peak value information. The proposed estimation method achieved an error rate of less than 1.5% through simulation, and it was verified that the estimation method could be effectively applied.