A novel Topology of Delta Modulation Technique for Improving the Power Factor of AC-DC Converters
Walid Emar
Journal of Information Technology Review, Vol. 1, No. 1, 2010.
DOI: 
Link: http://www.dline.info/jitr/fulltext/Paper-01.pdf
Abstract:
This work presents a new topology of delta modulation technique. This kind of modulation technique is usually used to improve the power factor of Pulse Width Modulation (PWM) converters used for supplying A.C. drives. Many new topologies have been presented trying to obtain a cost-effective solution to reduce the input current harmonic content and to make it sinusoidal and in phase with the input voltage of AC-DC converters. Each one of them has its application range due to the inherent characteristics of the topology (See [2]). Obviously, not every converter is useful for the same application. Hence, this paper tries to show the most appropriate topology of different variants of modulation technique used for power factor correction. This technique which is used to generate the PWM control signals for the main devices of the PWM converter has the advantage of yielding instantaneous current control, resulting in a fast response [3], [4]. However, the switching frequency is not constant and varies over a wide range during each half-cycle of the A.C. input voltage. Furthermore, the frequency is also sensitive to the values of the circuit components, which is also addressed in this paper. This new delta modulation technique topology proves to give great stability performance over other variants of delta modulation or other modulation techniques.