PFC Converter Examples¶

Power Factor Correction circuits for AC-DC conversion.

Overview¶

PFC converters shape input current to be sinusoidal, achieving: - Near-unity power factor (>0.99) - Low THD (<5%) - Regulatory compliance (IEC 61000-3-2)

Circuit Files¶

• pfc_boost_ccm.ipes - CCM boost PFC
• pfc_boost_crm.ipes - Critical conduction mode
• pfc_interleaved.ipes - Two-phase interleaved
• pfc_bridgeless.ipes - Totem-pole bridgeless

Specifications¶

Single-Phase Boost PFC¶

Theory¶

Boost PFC Operation¶

Input current follows rectified voltage shape: $\(i_{in}(t) = I_{pk} \cdot |\sin(\omega t)|\)$

Duty cycle varies with instantaneous voltage: $\(D(t) = 1 - \frac{|v_{in}(t)|}{V_{out}}\)$

Control Methods¶

Average Current Mode: - Current loop tracks sinusoidal reference - Excellent THD performance - Bandwidth limited by 2× line frequency

Critical Conduction Mode (CRM): - Variable frequency - Zero current turn-on - Higher peak currents

Interleaved PFC¶

Benefits: - Ripple cancellation at input - Reduced capacitor current - Smaller inductors - Distributed thermal load

Phase shift between channels: 360°/N

Bridgeless Topologies¶

Totem-Pole PFC¶

• Eliminates input bridge
• Higher efficiency (~0.5% gain)
• Requires GaN/SiC for CRM operation
• Bidirectional capable

Exercises¶

1. Power Factor Measurement: Verify PF and THD
2. CCM vs CRM: Compare inductor current waveforms
3. Interleaving Effect: Observe ripple cancellation
4. Efficiency: Compare topologies

Related Resources¶

• 302 - PFC Basics Tutorial
• Vienna Rectifier Tutorial