AC Mains Synchronization Loop for Precalculated- Based PFC Converters Using the Output Voltage Measure

Abstract

Common implementations of power factor correction include sensors for the input and output voltages and the input current. Many alternatives have been considered to reduce the number of sensors, especially the current sensor. One strategy is to precalculate the duty cycles that must be applied to every ac main, so the system only needs to synchronize them with the input voltage, and include a simple output voltage loop. The main problem with this approach is the sensibility to any synchronization error, because the input current is not measured, so its evolution is not continuously corrected. This paper shows how the synchronization error alters the current and the power factor, and it proposes several methods to detect and correct this error. All methods use the output voltage ADC, which is already used to control the output voltage, so the cost of the system is not increased. This technique can also be applied to any current sensorless PFC converter, because they are usually affected by leading or lagging currents, so the synchronization can be modified to reduce these effects. Results show that the implementation of this synchronization loop keeps a high-power factor under a wide synchronization error range, while the added logic is not significant.

Architecture of an efficient dual band 1.8/2.5 GHz rectenna for RF energy harvesting

“…The rectifying circuit consists of input terminal that simulating the RF input coming from the antenna, impedance matching circuit or power matching, five stage voltage doubler and resistance load. In the rectifier circuit, voltage doubler topology is preferred as it rectifies both positive and negative wave of the input signal [25]. In order to increase the amplitude voltage, each of the rectifier stage is connected in cascade.…”