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7C03I: Power Factor Correction: Why and How? -- John Pocs

Increasing energy efficiency is the goal of almost everyone these days. Power Factor (PF) is a measure of power quality and is the ratio between the actual power used (Active Power) and the delivered power (Apparent Power). Less than unity PF is caused by nonlinear, mostly inductive loads such as motor drives, switching power supplies, solid-state lighting fixtures, etc. Bad PF manifests itself in a phase shift between current and voltage with very large current spikes requiring thicker cables to deliver the power to the consumers. Bad PF also manifests itself in loss of power in the load in the form of reactive power that is consumed internally by the load without contributing to the production of useful work. Utilities are charging industrial and commercial customers for low power factor and are considering to charge individual consumers in the future. Power Factor Correction (PFC) means ideally achieving a close to unity PF by reducing the current spikes and eliminating the voltage current phase shift. This lecture explains the concept of power factor and introduces various analog and digital PFC topologies used in the industry. Both analog and digital PFC methodologies are presented in detail with pros and cons for each. Multi-channel interleaved PFC topology will be the highlight of the lecture with special emphasis on the digital implementation with Rx62T and Rx62G microcontrollers. http://renesasdevcon.com