Power Factor Correction (PFC) Products

Power factor correction (PFC) products are used to configure and correct the power factor in power systems. The power factor describes the power relationships on an ac power line. Current and voltage distortions occur with a reactive load, which has both a real and a reactive power component. The vector sum of these two power components is the apparent power to the load. The phase angle between the real power and the reactive power is the power factor angle. With a resistive load, the reactive power is zero and the apparent power equals the real power. The power factor is unity, or 100%. If the load is reactive, the power factor is lower (less than 100%). Understanding these power-factor characteristics is an important part of specifying power factor correction (PFC) products.

By design, power factor correction (PFC) products equalize the real power to the load and the apparent power. When this occurs, the reactive power is zero and the power is 1.0 or 100%. This is the ideal value for a power factor because, when the reactive power is zero, the power consumption due this reactive power is also zero. Consequently, power factor correction (PFC) products can help to reduce energy consumption and save money. In addition to power systems then, PFC products are used in homes, office buildings, AC equipment, and heavy-duty apparatus.

There are two basic types of power types of power factor correction (PFC) products: active and passive. Active PFC circuits use switch-mode converter techniques and are designed to compensate for distortion as well as displacement on the input current waveform. Active PFC circuits are significantly more complex, but this complexity can be managed with specialized control integrated circuits (ICs) for implementation. In addition, active PFCs operate at frequencies that are higher than line frequency so that compensation of both distortion and displacement can occur within the time frame of each line frequency cycle. This results in corrected power factors of up to 0.99. Passive power factor correction (PFC) products are also available. Typically, PFC circuits are used to build passive components such as resistors, capacitors and inductors. These products are basically filters.

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