Standard boost PFC
Typical operating frequency <70 kHz
– Keep fundamental and 2
nd
harmonic below 150 kHz EMI
– Increasing frequency increases switching loss
Control mode typically Continuous Conduction Mode
– CCM balances ripple current losses and switching loss
Can be operated Discontinuous or Critical mode
– Much higher ripple current
– But ZVS or near ZVS possible, much lower switching loss
Either way, dominant loss is input bridge rectifier
– 1-2% total efficiency loss due to input bridge
– Even a “perfect” zero loss switch can‟t make-up for bridge
APEC 2015 Seminar S17
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