A Current Sensorless Sliding Mode Controller for a Three Level Resonant Single Stage PFC AC/DC Converter

This paper presents a variable structure control method for a single stage three level resonant AC/DC converter. An observer with adaptive parameter estimation is also introduced to achieve current sensorless operation of the controller, thus returning the number of feedback measurements to two (both of which are voltage measurements) instead of three. Two switching functions are used: one to regulate the output voltage and the other switching function is to regulate both the input current and dc-bus voltage. This controller also makes the system response less sensitive to load variations, supply voltage changes and resonant tank parameter variations.