Series-loaded Resonant Converter Research Articles

Series-Loaded Resonant Converter DC-DC Buck Operating for Low Power

This paper presents the functions of Series-Loaded Resonant Converter (SLRC). Series Loaded Resonant DC-DC converter is a type of soft-switching topology widely known for providing improved efficiency. Zero voltage switching (ZVS) buck converter is more preferable over hard switched buck converter for low power, high frequency DC-DC conversion applications. Zero Voltage switching techniques will be used to improve the efficiency of current and voltage at the series loaded half-bridge rectifier. The results will be described from PSIM simulation, Programming of MATLAB calculation and hardware testing.

Effect of Resonant Capacitance and Inductance on Peak Capacitor Voltage and Inductor Current in SLR Converter

With an ever-increasing number of portable electronic devices being used worldwide, increasing attention has been drawn to efficiently charging and powering these devices. While conventional PWM-based topologies such as buck and flyback converters are ubiquitous in consumer electronics, the desire for increased efficiency, larger power output, and smaller size has caused engineers to look at other power supply topologies. One topology that can satisfy all of these desires is the Series-Loaded Resonant (SLR) converter. This topology uses a resonant tank to facilitate soft switching, resulting in very low switching losses, higher efficiency, higher switching frequencies, and smaller system size. This study examines how changing the capacitance and inductance values of the resonant tank affects the peak capacitor voltage and the peak inductor current which further impacts the sizing of all other components, and thus the overall cost of the converter. By characterizing these parameters, designers can more easily optimize component selection to achieve appropriate cost-benefit of their converter design.

Zero‐current switching series loaded resonant converter insensitive to resonant component tolerance for battery charger

This study proposes an electric vehicle (EV) battery charger with a fixed frequency zero-current-switching (ZCS) series loaded resonant converter (SRC). Owing to the proposed fixed frequency operation the SRC is capable of operating under ZCS turn on and turn off regardless of voltage variation or load variation, and the magnetic components and the electromagnetic interference (EMI) filters can be optimised. The proposed battery charger has minimum component count, which makes it possible to achieve low cost and high reliability. Also, it is insensitive to resonant component tolerances and therefore suitable for high volume manufacturing. Experimental results are provided from a 3.3 kW prototype which was built for 2011 Future Energy Challenge Competition.

Design and Test of a 35-kJ/s High-Voltage Capacitor Charger Based on a Delta-Connected Three-Phase Resonant Converter

This paper describes the design, implementation, and analysis of a 35 kJ/s high-voltage capacitor charger based on a delta-connected three-phase series resonant converter that provides a constant charging current with high efficiency and high-power density. In order to obtain the maximum output power for various charging voltages, each high-voltage transformer supplied by a delta-connected resonant inverter is designed with two secondary windings and voltage-doubled rectifiers. This configuration allows not only a flexible output current and voltage with fixed output power but also a high power factor on the input side. On the basis of the analysis of the series-loaded resonant converter operating at a discontinuous conduction mode, the details of the design procedure for the resonant inverter are provided. Furthermore, the implementation of the high-voltage transformers and rectifiers is also explained while considering insulation and compactness. Experiments were carried out on the developed charger with different types of capacitors, depending on their applications, and the results are discussed. In addition, malfunctioning tests were conducted for the open, short, and misfiring during charging conditions. Finally, the developed high-voltage capacitor charger was shown to be very reliable, even under faulty operating conditions in the system.

MODELING OF PARALLELED SERIES-LOADED-RESONANT CONVERTER WITH PHASE SHIFTING CONTROL

One topology widely known for use in high-voltage high-power converter in medical equipment is the Series Loaded Resonant (SLR) converter. As the power level required by medical equipment increases, there is a need to parallel the SLR converter for improved efficiency and performance. This paper presents the development of a circuit model for paralleled SLR converter to aid circuit designers evaluate circuit performance before the actual hardware is implemented. Each section of the circuit is modeled individually using sinusoidal approximation and circuit network methods. The derived model is then extended to include the parallel connection of the converter. The validity of the model is then tested by using computer simulation and hardware setup to demonstrate the converter's switching waveforms, output voltage and efficiency. Results from both simulation and hardware show good agreement, which demonstrate the validity of the derived model and its usefulness in the initial design of the converter.

Compact and high repetitive pulsed power modulator based on semiconductor switches

This paper describes the design of a compact and highly repetitive pulsed power modulator based on semiconductor switches. Output specifications of the proposed modulator are as follows: variable output pulse voltage, 1-10 kV; width, 1-10 μs; pulse repetition rate (PRR), 1-50,000 pps; and average output power, 10 kW. The proposed solid-state pulsed power modulator has two main parts: an IGBT stack that hasa gate drive circuit for the pulse output with a variable pulse width and repetition rate, and a capacitor charger that has a controllable output voltage. To connect all the storage capacitors in a series for high voltage pulses, a simple and reliable IGBT stack structure was proposed based on the Marx generator. In addition, the gate driver circuit, which supplies power and signals to all the IGBTs simultaneously, was introduced. This providesa superior protection function against the arc and the short. To charge the storage capacitors, a novel 10 kW (10 kV, 1 A) high voltage capacitor charger with the combined advantage of a series-loaded resonant converter and a ZVS (zero-voltage-switching) full-bridge pulse width modulation (PWM) converter was proposed and designed especially for the solid-state pulsed power modulator. Theexperiment results verified that the proposed scheme and structure can be used effectively for a high voltage pulsed power modulator that requires variable voltage, repetition rate, and pulse width, depending on the process of the applications.

Implementation and Analysis of an Improved Series-Loaded Resonant DC–DC Converter Operating Above Resonance for Battery Chargers

The well-established advantages of resonant converters, including simplicity of circuit configuration, ease of the control scheme, low switching losses, and low electromagnetic interference, among others, have led to their attracting more interest. This work develops a highly efficient battery charger with an improved series-loaded resonant converter for renewable energy applications to improve the performance of traditional switching-mode charger circuits. The switching frequency of the improved series-loaded resonant battery charger was at continuous conduction mode. Circuit operation modes are determined from the conduction profiles. Operating equations and operating theory are also developed. This study utilizes the fundamental wave approximation and a battery equivalent circuit to simplify the circuit analyses. The mean charging efficiency of the proposed topology is as high as 87.5%.

A novel single-stage half-bridge AC-DC converter with high power factor

A new single-stage AC-DC power converter based on a half-bridge converter suitable for low-power applications is proposed. The proposed converter offers high power factor and direct conversion from the line voltage to an isolated DC output voltage. High power factor is achieved by adding a resonant circuit between the rectifying diodes and half-bridge leg. For soft switching, a half-bridge series-loaded resonant converter is adopted as a DC-DC converter part. A prototype is built and tested to show the validity of the proposed converter.

Simple equivalent circuit for the series-loaded resonant converter with voltage boosting capacitor

A simple, fundamental frequency equivalent circuit is derived for the series-loaded resonant converter with voltage boosting capacitor. The equivalent circuit permits direct and straightforward calculation of the steady-state resonant current and voltage conversion ratio; previous analyses have used time-domain techniques requiring complex calculation and numerical solution. Comparison with results from an idealised time-domain simulation is used to quantify the errors introduced by the fundamental frequency approximation. Practical results from a 1 MHz prototype demonstrate the accuracy of the technique for converter design.

Multimodule parallel series-loaded resonant converters

The design and implementation of a multimodule parallel series-loaded resonant (SLR) converter system is presented. The SLR converter to be paralleled is operated in the n=2 discontinuous mode (DCM). Its dc analysis and dynamic modeling are made. In parallel operation, an average control technique is proposed to compensate the mismatch in current control characteristics of each parallel converter. Good dynamic and static current sharing characteristics are obtained. In addition, to obtain good output voltage regulating control performance, a design procedure is presented to find the parameters of feedback voltage controller according to the prescribed specifications. >