LCC resonant converter with power factor correction for power supply units

This article presents a power supply using an LCC resonant converter having power factor correction with burst mode operation. In order to improve the performance from no load to full load, a microcontroller with an active control has been introduced. The light load efficiency is increased using burst mode operation. The proposed controller provides zero voltage switching. Mathematical analysis is done, and steady state characteristics are drawn. A simple design example is given based on the equations. The proposed converter has good efficiency with good power factor at all loading conditions. This is shown by the simulation and experimental results obtained through testing the prototype.     

Single-stage unity power factor based electronic ballast

This paper deals with the design, modeling, analysis and implementation of unity power factor (UPF) based electronic ballast for a fluorescent lamp (FL). The proposed electronic ballast uses a boost AC–DC converter as a power factor corrector (PFC) to improve the power quality at the input ac mains. In this single-stage UPF based electronic ballast, boost PFC converter and a half bridge series resonant inverter (HBSRI) share a common power switch. Thus one power switch is reduced as compared to the conventional two-stage approach. The design, modeling, analysis and implementation of this topology were carried out in MATLAB-Simulink environment for a T8 36 W, 220 V, 50 Hz fluorescent lamp. The switching frequency was kept more than the resonant frequency of the inverter, to ensure the zero voltage switching (ZVS) operation of both power switches. This resulted in reduction of high frequency switching losses. The power quality parameters such as displacement power factor (DPF), distortion factor (DF), power factor (PF), crest factor (CF) and total harmonic distortion of ac mains current (THD_i) were evaluated to analyze the performance of proposed electronic ballast. Test results on a developed prototype of PFC electronic ballast were included to validate the design and simulated results.     

Displacement-phase-code converter with error correction

Conclusions 1) The use of phase converters with multichannel outputs enables us to calculate automatically the components of the error in a phase converter and use them for correcting the error. 2) The use of two-channel phase converters enables us to correct for only of the components of the error. 3) For full error correction, we need to use a phase converter with three or more output channels.Translated from Izmeritel'naya Tekhnika, No. 7, pp. 31–33, July, 1978.     

Effective reflection factor of waveguide transmitted power converter

The effective reflection factor of a convener with two sensitive elements on either two adjacent walls of a rectangular waveguide or on its wide wall is found and minimized. Translated from Izmeritel'anaya Tekhnika, No. 3, pp. 58–60, March, 1996.     

Single phase power factor correction — A review

This paper provides a comprehensive review of the past and recent developments in the area of single-phase power factor correction (PFC) techniques. The motivation for the research in this area, and the manifold directions into which the research has gained impetus, are clearly brought out. The various PFC techniques are broadly classified into (1) passive, (2) active, and (3) active-passive PFC techniques. The active PFC techniques, based on the output dynamics, are further classified into (1) conventional techniques which have slow output dynamics and (2) techniques with fast output dynamics. The critical issues within each PFC technique are discussed in detail. An extensive list of references is also provided at the end.     

High power factor operation of resonant converters on the utility line

Operation and characteristics of resonant converters on the utility line are presented. Series-parallel (LCC-type) resonant converter operating with discontinuous current mode and continuous current mode (variable frequency control as well as fixed-frequency) are considered. Design examples are presented. SPICE simulation and experimental results obtained for the designed converters (rated at 150 W) are presented to verify the theory. It is shown that high line power factor (>0.95) and line current total harmonic distortion (THD) of <25% are obtained for the LCC-type converter for a wide load range (from full load to 10% rated load) without any active control, and the switch peak current decreases with the load current. With active line current control, low distortion and zero voltage switching for the entire cycle are realized.     

High-efficiency single-stage bidirectional converter with multi-input power sources

A multiple-input, single-stage bidirectional converter is proposed. It takes a three-winding coupled inductor as the main component of energy transmission, and utilises only two switches to accomplish the multi-input mechanism. Depending on the switching conditions, the circuit can be operated at discharge, charge and alone states. The winding voltage in the high-voltage side of the coupled inductor is manipulated to further increase the corresponding voltage gain, a strategy that is superior to one in the conventional coupled-inductor. This topology is useful for low-power applications. In addition, all switches and diodes have favourable voltage-clamping effects so that the voltage spikes caused by the leakage-inductor energy can be alleviated effectively, and reverse-recovery currents within diodes can be reduced, because the leakage inductor has limited capability to handle quick current changes. There is also a low-voltage-type charge circuit with no increase in additional circuit elements. This helps -to avoid power losses that arise from multistage conversions in traditional auxiliary power systems. This strategy also utilises the synchronous rectification technique to further decrease conduction losses. Numerical simulations and experimental results via examples of a proton exchange membrane fuel cell power source and a traditional battery module are given to demonstrate the effectiveness of the proposed power conversion strategy.     

Discontinuous conduction mode analysis of phase-modulated series resonant converter

This paper proposes an analytical approach to derive voltage gain for phase-modulated dc–dc series resonant converter (SRC) operating in discontinuous conduction mode (DCM). The conventional fundamental harmonic approximation technique is extended for a non-ideal series resonant tank to clarify the limitations of SRC operating in continuous conduction mode (CCM). The DCM analysis is described in a normalized form defining appropriate base quantities. The converter is analysed both in time and frequency domain to derive a non-linear algebraic function of diode rectifier extinction angle. The root of this function is numerically determined using MATLAB and used to predict the dc bus voltage. Analytical derivation of critical load resistance is discussed, which indicates the CCM–DCM boundary condition. Experimental results are presented to validate the analysis.     

Stress-strain state of a longitudinal-bending converter under resonant oscillations

Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Problemy Prochnosti, No. 6, pp. 81–84, June, 1989.     

Diffractive element design for resonant scanner angular correction

We propose an optical corrective element with zooming capability to convert nonlinear sinusoidal scanning into linear scanning. Such a device will be useful for linearizing the angular scan of a resonant mirror scanner. The design methodology is to create a graded index of refraction device as the reference design, with its index of refraction parameters based on the propagation of an electromagnetic field in inhomogeneous media. The algorithm for converting this refractive element to the corresponding binary diffractive version is also presented. Design and simulation data are shown.     

改善的全桥变流器中谐振电容的研究

在倍流型整流零电压开关脉宽调制全桥变流器中引入一个谐振电容降低了对变压器漏感的限制，实现了在更宽负载范围内零电压开关以及整流二极管无电压振荡的自然整流，本文对改进的零电压开关脉宽调制全桥变流器的工作原理、谐振电容的作用以及谐振电容值的确定进行了分析，并在实验室建立了一个输出功率540W(54V，10A)的变流器进行了验证。     

Active power decoupling with reduced converter stress for single-phase power conversion and interfacing

Single-phase DC–AC power electronic converters suffer from pulsating power at double the line frequency. The commonest practice to handle the issue is to provide a huge electrolytic capacitor for smoothening out the ripple. However, the electrolytic capacitors having short end of lifetime limit the overall lifetime of the converter. Another way of handling the ripple power is by active power decoupling (APD) using the storage devices and a set of semiconductor switches. Here, a novel topology has been proposed in implementing APD. The topology claims the benefit of (1) reduced stress on converter switches and (2) using smaller capacitance value, thus alleviating the use of electrolytic capacitor and in turn improving the lifetime of the converter. The circuit consists of a third leg, a storage capacitor and a storage inductor. The analysis and the simulation results are shown to prove the effectiveness of the topology.