Jan. 15, 2010 - 3kW Single Phase PFC with 99.2% Efficiency

Power density (output power per volume) has been an important research topic for years in the Power Electronic Systems Lab., ETH Zurich. But now the idea was to maximize efficiency, and the research group around J. W. Kolar & J. Biela realized a single-phase PFC prototype with 99.2% efficiency (measured via calorimeter). Details of this optimization will soon be published at the APEC 2010.

Key elements of the successful optimization:

• Careful selection of the topology >> Bridgeless PFC
• CoolMOS-transistor & SiC Schottky diode
• Careful optimization of the integrated magnetics at the AC side
• Consideration of switching losses due to semiconductor-capacity
• Complex mathematical optimisation procedure including GeckoCIRCUITS

 
Fig. 1: Efficiency-optimized single-phase PFC in GeckoCIRCUITS. 

GeckoCIRCUITS is extremely fast and can be easily integrated into an optimization environment. Is also allows very convenient calculation of all kind of losses. You can perform online-simulations of the selected topology by clicking the orange rectangle on this page. Please note that the very important EMI filter is omitted and the converter control is extremely simplified in this online-simulation.

Screenshot Fig. 3 on that page shows that with the selected parameter set the system losses would be pvTotal (avg) = 23.55W with an output power of pOUT (avg) = 3.13kW resulting in efficiency = 99.25. Additional losses for EMI-filter components and control have to be considered.

 
Fig. 2: Waveform of losses of MOSFET-switches (switching & conduction), diodes, inductive components and capacitor.  

 
Fig. 3: Analysis-tool built into SCOPE (Analysis >> Characteristics) to calculate output power and losses.