Power factor correction (PFC) circuit basics
From laptop adapters to power tools, any end equipment powered from the AC grid represents a complex load where the input current is not always in phase with the instantaneous line voltage. As such, the end equipment consumes both real power as well as reactive power from the grid. The ratio between real, usable power (measured in watts) and the total real-plus-reactive power is known as the power factor. A power factor correction (PFC) circuit intentionally shapes the input current to be in phase with the instantaneous line voltage and minimizes the total apparent power consumed. While this is advantageous to utility companies, a PFC circuit also provides benefits in end applications. This topic presents these benefits, how the PFC circuit can impact the AC-to-DC power-conversion architecture, common PFC circuit types, the benefits/disadvantages of different approaches and a PFC solution selection process based on end-equipment priorities.
Why should I take this training?
- Circuit topologies discussed are applicable outside of PFC
- Review of compensation techniques and small signal analysis
- PFC is needed for almost all AC/DC supplies over 75 W of output power
What will I learn?
- Basics of PFC and why it is necessary
- What standards are used to measure PFC
- Topologies that can be used for PFC
- Tradeoffs and real-world examples of PFC design