09-10-2010, 10:02 AM
[attachment=5463]
ABSTRACT
This paper presents a new 3-level, single-phase, pulse width modulated (PWM), boost-integrated acto- dc series resonant converter (SRC) with high frequency transformer isolation. This converter uses a new gating scheme suitable for integrating boost converter and PWM 3-level dc-to-dc SRC converter with above resonance operation. Principle of operation and different operating modes are presented with analysis. Based on the analysis design example of a 1 HP, 280 V, 50 kHz ac-to-dc series resonant converter is presented to explain design procedure. PSPICE simulation results of the designed converter are presented for different loads. Results show soft-switching operation, low switch voltage and low total harmonic distortion of this converter for a reasonably wide range of loads.
INTRODUCTION
In recent decades, research on ac-to-dc converters with power factor correction and low total harmonic distortion (THD) is consistently enjoying increasing interests. As the industry interests and applications of these converters increase, enforcing agencies are coming up with more stringent harmonic standards such as IEC 61000-3-2, ANSI/IEEE-519, etc. Implementation of these standards calls for front-end power factor correctors (PFC) requiring additional components, cost, reduced efficiency and increased size. Singlestage ac-to-dc converters address most of these challenges. All of these converters are operating in discontinuous current mode (DCM) with very high peak device current and offer further study to reduce under-utilization of its current capacity. In a single-stage series resonant converter was presented. This work showed that by using resonance phenomenon the device peak current were reduced significantly but the bus voltage increases at light load and maximum input voltage. In 3-level converter are proposed to reduce switch voltage resulting from high bus voltage. Therefore, the motivation of this study is to reduce switch voltage and current simultaneously at different load conditions while power factor correction is obtained by integrating front-end PFC with the dc-to-dc stage of the converter.
This paper proposes a new single-phase, 3-level, single-stage ac-to-dc series resonant converter and investigates its behaviour for a wide load range. The objectives of this paper are: (a) to explain the operating principle of this converter with DCM operation of the integrated boost PFC (b) to identify different modes and intervals of operation, © to present a design example to illustrate the design procedure, and (d) to verify converter operation and performance using PSPICE simulation results for different load conditions.
These objectives are outlined in this paper as follows: Section II presents principle of operation. Different modes and intervals are identified and analysed in Section III. Section IV presents a design example to illustrate the design steps. PSPICE simulation results are presented in Section V. Section VI concludes this paper.
