There's an increasing need for high-efficiency power conversion for a wide range of applications. Among the several available power factor correction (PFC) solutions, the critical conduction mode (CrM) PFC is a preferred method, especially for lower-power applications, because of its simpler control scheme. However, the design will have problems caused by the wide operating frequency range. One simple solution is to limit the maximum operating frequency, with the accompanying drawback of increased total harmonic distortion (THD). As will be shown in this article, an innovative PFC solution, frequency clamp critical conduction mode (FCCrM), clamps the frequency with a near-unity power factor while maintaining the benefit of CrM PFC.
By developing a greater understanding regarding electric motor efficiency and operating characteristics, you can realize some serious electric energy cost savings. An often overlooked and widely misunderstood characteristic of electric motors is power factor (PF). Proper electric motor application and efficiency are important things to know when applying or replacing a motor, although PF can be equally important when operating costs are considered.
The improvement measures implemented resulted in a plant PF of 93%, eliminating the $276 monthly PF charges. The measures also resulted in an average monthly plant peak demand reduction of 10kW — a $90 monthly savings. The project payback was less than 18 months. Note: The plant had an existing, functioning 200 kVAR fixed capacitor in place at the main electric service entrance for PF support before this project began. This capacitor remains in place.