CUK Converter for Power Factor Correction Using Moth Flame Optimization-PI Controller

This paper presents the comparison of LED driver topologies that include SEPIC, CUK and FLYBACK DC-DC converters. Both topologies are designed for 8W power and operated in discontinuous conduction mode (DCM) with 88 kHz switching frequency. Furthermore, inductors of SEPIC and CUK converters are wounded as coupled. Applications are realized by using SG3524 integrated circuit for open loop and PIC16F877 microcontroller for closed loop. Besides, ACS712 current sensor used to limit maximum LED current for closed loop applications. Finally, SEPIC, CUK and FLYBACK DC-DC LED drivers are compared with respect to LED current, LED voltage, input voltage and current. Also, advantages and disadvantages of all topologies are concluded.

A single-phase bridgeless Cuk ac/dc power factor correction (PFC) rectifier with positive output voltage is proposed in this paper. For low output voltage product applications, the rectifier is designed to convert high input voltage to low output voltage. Due to no bridge diodes required and thus decreased input conduction losses, the proposed rectifier efficiency can be improved. The proposed rectifier operates in discontinuous conduction mode, and the current-loop circuit is hence not needed. In addition, only a single switch is used in the rectifier to simplify the control circuit design. A simple translation method to have the positive output voltage in the Cuk converter is presented in the rectifier to reduce the component counts and the cost. The operational principles, steady-state analysis, and design procedure of the proposed rectifier are addressed in detail in this paper. Simulation and experimental results obtained from a 150-W rated prototype circuit with input of 90-130 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rms</sub> , 60 Hz, and output of 48 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dc</sub> have verified the validity of the proposed rectifier.

Constant frequency controllers designed for continuous conduction mode (CCM) give poor efficiency and power factor at light load in power factor correctors (PFCs) of computer and server power supplies. With the increasing efficiency and power factor requirements at light load demanded by energy saving programs, a multimode digital control scheme that provides higher efficiency and power factor at light load without additional and costly external components is proposed. The CCM-DCM control of the multimode control scheme reduces RMS current drawn from the AC mains by ensuring good input current shaping in both CCM and discontinuous conduction mode (DCM), leading to higher efficiency and power factor at light load. It is computationally simple as compared to other CCM-DCM control schemes. The no load control of the multimode control scheme reduces constant losses at very light load by turning the PFC on and off to regulate the output voltage within a hysteresis band. Compared to other on-off control schemes, a small load jump is sufficient to exit the proposed no load control scheme, allowing a smooth transition between the no load control and the CCM-DCM active mode control.

In response to the growing need for efficient power conversion in renewable energy applications, this study addresses the issue of harmonic distortion and low Power Factor (PF) values caused by non-linear loads, such as electronic devices. Low PF results in reduced efficiency, increased energy consumption, and higher costs for both consumers and utilities. Active correction, typically involving an active circuit implemented using a power converter, provides an optimal solution by offering high performance, precise regulation, and low harmonic distortion. This research proposes a Power Factor Correction (PFC) solution utilizing an Interleaved DC-DC Single Ended Primary Inductance Converter (SEPIC) for the power stage and a Proportional Integral Derivative (PID) controller for the control block, tuned by a Quorum Sensing (QS) bacterial-based search algorithm. The PID controller parameters are derived using a frequency-domain approach, which presents advantages such as reduced design complexity, improved stability margins, and enhanced SEPIC performance. Simulation results indicate reduced overshoot, settling time, rise time, and Total Harmonic Distortion (THD) percentage, as well as increased efficiency and power factor nearing unity. The proposed scheme also demonstrates improved dynamic performance for variations in load, line, and reference voltage. Owing to its high efficiency, precise voltage regulation, and minimized impact on the electrical grid, this solution is well-suited for renewable energy applications, where optimizing energy conversion and ensuring stable operation are crucial for the overall performance of renewable energy systems.

In this paper, a high power factor based isolated dual output Cuk converter fed SRM drive is proposed. The selected converter is featured with two equal output power sources, DC isolation and improved power quality operation over a complete input voltage range and loading conditions. To obtain input current shaping, DCM (Discontinuous Conduction Mode) of operation is selected, which presents the most simple and low cost control as compared to CCM (Continuous Conduction Mode), and CRM (critical conduction mode). It has resulted in the reduced size and cost of magnetic structure considerably. The speed control of proposed drive is based upon DC link voltage control, which is obtained by modulating pulse width of the Cuk converter. Experimental results of a prototype of isolated Cuk converter fed SRM drive is demonstrated here. The obtained input current THD complies with given regulation for harmonics, such as an IEC 61000-3-2.

In an electrical Power system, the current drawn by power converter devices from the line is distorted resulting in a higher Harmonic Distortion and low Power Factor (PF). Hence, there is a continuous need for power factor improvement and reduction of line current harmonics. Here, an Active Power factor Correction method is proposed to improve the PF and to regulate the Output Voltage of a Single Phase AC to DC Boost Converter. Small signal modeling of single-phase full bridge rectifier and its modes of operations are discussed. The inner Voltage loop is controlled by PID controller and sliding mode control is used for controlling the Outer current loop. An overall comparison is made for various voltages and loads. Output voltage tracking is also analyzed. The main aim of the proposed work is to maintain the power factor above 0.95 and to reduce the total harmonic distortion below 5%. Simulation is carried out using MATLAB software.

Dual Randomized Pulse Width Modulation (DRPWM) is renowned for its better effectiveness than Simple Randomized Pulse Width Modulation (SRPWM) in reducing conducted Electro-Magnetic Interferences (EMI) in power converters. However, the introduction of low-frequency ripples into the output voltage by dual randomization has not yet been addressed; this effect is investigated in this paper for a buck converter operating in both the continuous conduction mode (CCM) and the discontinuous conduction mode (DCM). First, the modulating principle is presented. Then, a general analytical expression for power spectral density (PSD) of the input current is derived and validated for the proposed DRPWM scheme for both the CCM and DCM. A comparison of the PSDs of the input current for all RPWM schemes in both the CCM and DCM shows the PSD spreading effectiveness of the dual scheme as compared to simple schemes. Finally, the low-frequency output ripple is analysed using the PSD of output voltage. The results reveal that the output voltage ripple is affected by all the randomized schemes in both the CCM and the DCM. Also, the dual scheme (RCFM-RPPM) introduces the highest low-frequency voltage ripple, especially in the CCM and for low duty cycles. In DCM, the RPPM scheme gives the lowest voltage ripple, while the RCFM scheme gives the lowest voltage ripple in the CCM. The results are confirmed by both theory and simulations.

Aim of this paper is to discuss about power quality of the AC system, which has become a great concern due to the rapidly increased use of inductive loads, electronic equipment (Linear and Non linear load). We are wasting a part of the electrical energy everyday due to the lagging power factor in the inductive loads which is used in the system. Hence, there is an urgent need to avoid this wastage of energy, lower power factor and reactive power results in poor reliability, safety problems and high energy cost. The power factor of power system is continuously changing due to differences in the size and number of the equipment being used at a time. This makes it challenging to balance the inductive and capacitive loads continuously. Many control methods for the Power Factor Correction (PFC) were proposed. This paper presents a computationally accurate technique to design and development of a single phase as well as three phase power factor correction, reactive power and THD compensation using Arduino Uno micro-controlling chip. The hardware implementation is developed by using Arduino Uno board.

This paper deals with an input power quality improvement in an Asymmetric Converter based switched reluctance motor (SRM) drive at ac mains using a Reactor circuit. Normally an asymmetric converter is used as a power converter for SRM drive. Conventionally three phase ac mains fed bridge rectifier is used as a dc source to feed this power converter which produces high content of harmonics at ac mains with a very low power factor. The proposed circuits with an asymmetric converter fed SRM drive enhance the power factor at ac mains with low current harmonics. By this method we can get almost constant dc link voltage which can be applied to the converter. The proposed SRM drive is modelled and its performance is simulated in Matlab/Simulink environment. The performance of the reactor circuit topology is compared with a conventional SRM drive to demonstrate improved power quality at ac mains.

Buck-buck/Boost power factor correction (PFC) converter is a great choice to compensate the inherent dead zones in the input current of buck PFC converter. However, whether the converter operates with traditional constant on-time control in critical conduction mode (CRM) or with conventional constant duty-cycle control in discontinuous conduction mode (DCM), the power factor (PF) is low, especially at low input voltage. Therefore, fixed on-time ratio control (FOTRC) and fixed duty-cycle ratio control (FDCRC) are proposed for CRM/DCM buck-buck/boost PFC converter to achieve high PF, respectively. Both control methods maximize PF over wide input voltage range by adjusting on-time or duty-cycle of buck/boost mode and buck mode. Compared with the traditional controls, the proposed control methods also have advantage of increasing efficiency. Furthermore, for improving dynamic response performance, smooth and rapid dynamic response control (SRDRC) is put forward, which can reduce the regulation time and output voltage overshoot/undershoot when the load or input voltage changes abruptly. In addition, the implementation circuits combining FOTRC/FDCRC and SRDRC are designed. Two prototypes have been built and tested in the lab to demonstrate the validity of the theoretical analysis.

A simple scheme is proposed for offline unity power factor rectification for high-frequency AC buses (20 kHz). A bandpass filter of the series-resonant type, centered at the line frequency, is inserted between the line and the full-wave rectified load. The Q=Z/sub 0//R/sub L/ formed by the load and the characteristic impedance of the tank circuit determines the power factor, the boundary between continuous and discontinuous conduction modes, the peak stresses, and the transient response of the rectifier. It is shown that for Q>2/ pi the rectifier operates in continuous conduction mode and the output voltage is independent of the load. Also, it is shown that for Q>2 the line current is nearly sinusoidal with less than 5% third-harmonic distortion and the power factor is essentially unity. An increase in Q causes an increase in the peak voltages of the tank circuit and a slower transient response of the rectifier circuit. The DC, small-signal, and transient analyses of the rectifier circuit are carried out, and the results are in good agreement with simulation and experimental results. >

A number of studies have shown that better DG PV integration impacts, on the network are obtained when the DG PV are operated at lower power factors. However, at lower power factors, losses tend to increase, whilst voltage improvement is rather realized in the sub - transmission network. In this study, with the help of the CYME distribution software, the optimal impacts of varying the DG PV power factors on the ECG 33 kV sub - transmission network voltages and losses, are studied. The study revealed that as power factors at which DG PV is operated are reduced, bus voltages generally increase. However, losses rather tend to follow a U-shape trajectory. The minimum loss recorded in the sub-transmission network was 1.032 %, representing a 6.522 % reduction over the base case scenario value of 1.104 %. The corresponding optimal power factor of the DG PV was found to be 0.97.

In this paper, a decoupled voltage mode control (DVMC) is proposed for a single-input dual-output Cuk converter (SIDO-CC) to eliminate the cross-coupling (CC) effect and maintain the desired output voltage. The DVMC consists of a decoupled network and a PI-based voltage controller. The SIDO-CC is synthesized from the conventional single input single output (SISO) Cuk converter by inserting an additional switch and inductor. However, the coupled capacitor present in the converter topology leads to a CC problem, which affects the converter stability. Therefore, a decoupling network is used in DVMC to eliminate CC among the control loops to allow independent controller design. Furthermore, in DVMC, two PI-based voltage control loops are designed to maintain constant output voltage during all operating conditions of the converter. To understand the system dynamics, a small-signal analysis of SIDO-CC is carried out using the state-space averaging technique, which yields system transfer functions for controller design. The proposed controller effectively traces the output voltages to desired values in the presence of input and output disturbances, which is validated by MATLAB simulations results.

This paper extends the voltage-doubler concept to the single-phase SEPIC rectifier in discontinuous conduction mode and, as a consequence, novel rectifiers are proposed. A comparison with the classic SEPIC rectifier shows that the proposed converters can either provide reduced voltage stress on the semiconductors for the same output voltage level or supply double the gain of the output voltage with the same voltage stress. The proposed voltage-doubler SEPIC rectifiers provide a high power factor with no current control and they can be applied in order to improve the static gain of the structure, which can make the SEPIC rectifier suitable for applications that require a high voltage level. In this paper, the generic structure based on a three-state switch, four different implementations of the proposed concept (including bridgeless structures), steady-state analysis, a dynamic model, system control, and experimental results are presented. The proposed rectifiers were verified by experimental results obtained with a prototype built with the following specifications: 1000 W output power, 220 V input voltage, 400 V output voltage, and 50 kHz switching frequency. Peak efficiency of 95.84%, THD of 2%, and power factor of 0.9997 were obtained and, most importantly, double the gain of the output voltage was verified.

The switched reluctance motor (SRM) has the advantages of simple structure, low rotor inertia and high power rate per unit volume. However, the SRM has the disadvantages of high current harmonics and low power factor because of the pulse-type discontinuous excitation. This paper investigates an SRM drive system with reduced harmonics and improved power factor. The system consists of a switching power converter with power factor correction (SPC-PFC), a DC/DC power converter and a three-phase inverter. The SPC-PFC is designed to produce a pure sinusoidal input current, improve the power factor and reduce harmonics. The performances in the proposed system are verified through both simulation and experiments.