Quasi‐constant bus voltage CrCM boost PFC fed LLC resonant converter in high power LED lighting systems

Abstract

This paper deals with a two-stage LED (light emitting diode) driver on the basis of front-end boost converter operating in critical conduction mode (CrCM) and second stage LLC resonant converter for driving an LED lighting load. The boost converter operates in the valley switching mode to reduce switching power loss with less component stress. The ZVS (zero voltage switching) operation of both the half-bridge semiconductor switching devices reduces the switching losses, which improves the system efficiency. Moreover, to ensure the stability of the DC-bus voltage, state-space analysis is also carried out for the CrCM boost converter. The first stage provides the power factor correction (PFC) over the universal AC mains and maintains a constant DC-bus for the next stage. The second-stage converter maintains a ripple-free output voltage to an LED load. This circuit has reasonably minimized the design complexity as compared with single-stage variable DC-bus PFC integrated resonant converters and also gives improved efficiency in an isolated configuration. In order to validate the system, a 150-W prototype is investigated, and experimental findings are analyzed in-line with theoretical results at universal AC mains.

Non‐isolated high step‐up/step‐down quadratic converter for light‐emitting diode driving

“…The possibility of associating a front‐end boost converter operating in critical conduction mode (CrCM) and an LLC resonant converter is investigated by Pal et al 14 The control system of the PFC stage is significantly simplified because it is only necessary to regulate the voltage across the intermediate DC link. However, the conduction losses in semiconductors are high, which may affect the overall efficiency.…”

Constant DC‐bus critical conduction mode Zeta converter fed primary‐side regulated LLC resonant converter in LED lighting applications

“…Several other single-stage and multistage converter topologies in LED lighting applications are discussed in previous studies. [24][25][26][27] The Zeta converter is selected as a PFC because of its unique benefit of lower DC-bus capacitance than other DC-DC converters. 9,11 A low DC-bus capacitor improves the efficiency and life of the converter.…”

Performance analysis of a bridgeless power factor correction (PFC) buck–boost LED driver with ripple diversion scheme for extended lifespan

“…Two-stage LED drivers [14][15][16] have a dedicated stage for PFC operation and a DC-DC conversion stage for adequate control of the constant output current. Hence, these converters outperform in terms of overall performance such as reliability, disposing of ECs, and superior control optimization for a wide range of input voltage variations.…”