TDK has confirmed that the request for recognition of intellectual property relating to controller PFC (Power Factor Correction) for power supplies TDK-Lambda, was approved by’UK Intellectual Property Office.
The requirements for the reduction of harmonic currents in industrial power supplies are in place for many years, and in Europe the standard of reference is the’IN 61000-3-2. Although power supplies up to 100W can meet the limits with a power factor equal to 0.6, when the power increases, è necessario avvicinarsi all’unità. La modulazione “sinusoidal” input current is a common method to achieve this goal. The switching losses in a PFC circuit, however, have a negative impact on system performance. Turn off the PFC circuit maintaining the conduction angle in the vicinity of the zero crossing is useful for the purposes of increasing the efficiency.
The controller owner of TDK-Lambda, uses digital control to manage the conduction angle while maintaining the level harmonic compliant along all values of the load. The control parameters of the digital circuit can be modified depending on the requirements on the levels of harmonics, for example in certain applications such as the LED driving or in PC power supplies, which present more stringent limitations.