Power Factor Correction Cuk Research Articles

Redundant Operation of a Parallel AC to DC Converter via a Serial Communication Bus

The redundant operation of a parallel AC to DC converter via a serial communication bus is presented. The proposed system consists of three isolated CUK power factor correction modules. The controller for each converter is a dsPIC30F6010 microcontroller while a RS485 communication bus and the clock signal are used for synchronizing the data communication. The control strategy of the redundant operation relies on the communication of information among each of the modules, which communicate via a RS485 serial bus. This information is received from the communication checks of the converter module connected to the system to share the load current. Performance evaluations were conducted through experimentation on a three-module parallel-connected prototype, with a 578W load and a -48V dc output voltage. The proposed system has achieved the following: the current sharing is quite good, both the transient response and the steady state. The converter modules can perform the current sharing immediately, when a fault is found in another converter module. In addition, the transient response occurs in the system, and the output voltages are at their minimum overshoot and undershoot. Finally, the proposed system has a relatively simple implementation for the redundant operation.

New Bridgeless DCM Sepic and Cuk PFC Rectifiers With Low Conduction and Switching Losses

New bridgeless single-phase ac-dc power factor correction (PFC) rectifiers based on Sepic and Cuk topologies are proposed. The absence of an input diode bridge and the presence of only two semiconductor switches in the current flowing path during each switching cycle result in less conduction losses and improved thermal management compared to the conventional Sepic and Cuk PFC converters. The proposed topologies are designed to work in discontinuous conduction mode (DCM) to achieve almost unity power factor in a simple and effective manner. The DCM operation gives additional advantages such as zero-current turn-on in the power switches, zero-current turn-off in the output diode and reduces the complexity of the control circuitry. The proposed rectifiers are theoretically investigated. Performance comparisons between the proposed and conventional Sepic PFC rectifiers are performed. Simulation and experimental results are provided for a design example of a 65-W/48-V at 100- V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rms</sub> line voltage to evaluate the performance of the proposed PFC rectifier.

Intermediate-scale instability in one-cycle controlled Cuk power factor correction converter

Based on the autonomous character of one-cycle control, the average model of one-cycle controlled Cuk power factor correction converter can be derived. Subsequently, the approximate analytical expressions of periodic solutions are obtained by using the harmonic balance method. Furthermore, through analyzing the changing trend of Floquet multipliers, the location and the type of the first bifurcation point are predicted. Thus, the intrinsic mechanism of such an instability can also be explained. The results show that the intermediate-scale instability is due to the loss of stability of periodic solutions, which is named the Neimark-Sacker bifurcation in the circuit system. Finally, experimental results are presented for verification purpose. Our work has revealed the salient feature of the intermediate-scale instability, and provided a theoretical basis for facilitating design of the converter.

Analysis and Design of a Parallel CUK Power Factor Correction Circuit Based on Power Balance Control Technique

The analysis and design of a parallel AC to DC CUK converter circuit based on power balance control technique for DC Distributed Power System (DPS) applications are presented. The three parallel modules system with fast dynamic response using single voltage loop control and inductor current calculator for input current wave shaping, inductor current sharing and output voltage regulation, while keeping the power factor very close to unity have been shown. The experimental prototype have been built with a DC output voltage -48V and output power 750W. Each converter operates in Continuous Conducting Mode (CCM) together with hysteresis current control. The experimental results indicate that such scheme is effective and offers the fast transient response. The results obtained are: power factor greater than 0.99 and input current Total Harmonic Distortion (THD) less than 3%. The system offers 85% efficiency and provide good current sharing among the converter modules.

Fuzzy Logic Controller Based LED Dimmer with Two-Stage PFC Cuk Converter

Abstract— This study presents a two-stage power converter with power factor correction (PFC) capability, designed for fuzzy logic-controlled LED dimming applications with a power rating of 150W. The first stage employs a Cuk converter, which ensures reliable PFC operation, minimizes current harmonics. A low-bandwidth compensator for the PFC stage is designed using the state-space averaged small-signal model of the Cuk converter to effectively suppress the harmonic component at twice frequency of the AC mains. The second stage utilizes a synchronous buck converter to regulate the LED array current for dimming process. A fuzzy logic controller has been used for the LED driver to enable fast and robust dimming. The twostage converter has been simulated in MATLAB/Simulink digital simulation environment, and the results have confirmed its ability to precisely control the LED array current while maintaining unity power factor at the AC mains.