AC-DC converters typically include rectifiers that convert AC voltage into DC voltage, but this process often results in non-sinusoidal, pulsed current that lowers the power factor (PF). A low PF means more apparent power is drawn relative to the real power used for work, leading to increased current flow, higher losses in power systems, and reduced capacity of the electrical network. PFC circuits shape the input current to align with the voltage waveform, improving PF and efficiency.

Benefits of PFC in Industrial and Commercial Use

• Energy Efficiency: Correcting the PF reduces wasted energy in cables, transformers, and circuitry, which decreases overall power losses.
• Reduced Electrical Costs: Many utilities impose penalties for low PF or charge based on apparent power demand (kVA). PFC lowers these charges by improving the PF and reducing peak demand.
• Increased System Capacity: By reducing the extra current drawn due to reactive power, PFC frees up capacity in electrical circuits, delaying costly upgrades and enabling more loads to be connected safely.
• Improved Voltage Stability: Reduced current flow from better PF results in lower voltage drops along conductors, resulting in more stable voltage supply to equipment.
• Enhanced Equipment Life: Lower reactive power reduces overheating and stress on electrical devices, extending their operational life and reducing maintenance costs.

Types of PFC and Application in AC-DC Converters

PFC can be passive or active. Passive PFC uses simple components like inductors and capacitors suitable for low-power applications. Active PFC, commonly used in industrial AC-DC converters, employs electronic circuits such as boost regulators that dynamically shape the input current to improve PF close to unity (1.0), ensuring compliance with international standards and enhancing converter performance.