Parallel Resonant Converter Research Articles

Stability Analysis of Series Parallel Resonant Converter with Fuzzy Logic Controller Using State Space Techniques

A closed-loop inductance capacitance inductance-T (LCL-T) series parallel resonant converter has been simulated and presented in this article. The fuzzy logic controller has been used for closed-loop operation, and the performance of the proposed converter has been estimated with a closed-loop condition. The steady-state stability analysis of the LCL-T series parallel resonant converter has been analyzed using the state-space model and simulated using MATLAB (The MathWorks, Natick, Massachusetts, USA). The proposed approach is expected to provide better voltage regulation for dynamic load conditions. A prototype 300-W, 100-kHz converter is designed and built for experimental demonstrations, and transient and steady-state performances for the LCL-T series parallel resonant converter are compared from the simulation studies.

Performance analysis of LCL-T resonant converter with fuzzy/PID controller using state space analysis

A closed loop series parallel resonant converter with LCL-T configuration has been simulated and presented in this paper. The fuzzy/PID controller has been used for closed loop operation and the performance of proposed converter has been estimated with the closed loop and the open loop condition. The mathematical model using state space approach has been developed and simulated using MATLAB. The performance of the converter has been found to be better when the fuzzy controller has been considered. The Harmonic Spectrum and steady state error for various load condition have been obtained to validate the role of controllers. The proposed approach is expected to provide better voltage regulation for dynamic load conditions.

Design and Implementation of a High Power Density Three-Level Parallel Resonant Converter for Capacitor Charging Pulsed-Power Supply

This paper describes the design and implementation of a prototype 30-kW (or 30-kJ/s) pulsed-power supply for capacitor charging. The system operates at 200-kHz maximum switching frequency, which is considerably higher than the conventional practice at this power level, leading to smaller passive components. A high power density of 143 W/in3 is achieved with the converter operating at a high ambient temperature of 65°C with 90°C cooling oil, by utilizing various technologies on topology, control, devices, passives, and thermal management. The experimental results demonstrate that the converter meets the performance requirements while achieving a high power density.

Analysis and implementation of LLC-T series parallel resonant converter using fuzzy logic controller

A modified LLC-T (inductor inductor capacitor) series parallel resonant converter (SPRC) has been simulated and the performance is analyzed. The limitations of two element resonant topologies have been removed by adding a third reactive element. The output voltage is regulated using fuzzy logic controller. The simulation study indicates the superiority of fuzzy control over the conventional control methods. The proposed approach is expected to provide better voltage regulation for dynamic load conditions. A prototype 300 W, 100 kHz converter is designed and built to experimentally demonstrate, dynamic and steady state performance for the LLC-T series parallel resonant converter. A comparative study is performed between experimental results and the simulation studies. The analysis shows that the output of converter is free from the ripples, and has constant current, regulated output voltage. Keywords : Resonant Converter, Fuzzy Logic, Control System, Power Electronics, MATLAB International Journal of Engineering, Science and Technology , Vol. 2, No. 10, 2010, pp. 35-43

Analysis and Implementation of Half-Bridge Series–Parallel Resonant Converter for Battery Chargers

This paper presents a novel application of half-bridge series-parallel resonant converter (HBSPRC) for dc source and secondary battery interface. The converter practically eliminates both low- and high-frequency current ripple on the battery, thus maximizing battery life without penalizing the volume of the charger circuit. Moreover, operation above resonance is preferred, because the power switches turn on at zero current and zero voltage; thus, the freewheeling diodes do not need to have very fast reverse-recovery characteristics. The proposed battery charger circuit has few components and low-energy conversion loss, which enhance the system's overall efficiency. Circuit operation modes are determined from the conduction profiles. Operating equations and an operating theory are also developed. Experimental results based on a 12-V 48-Ah battery charger are proposed to validate the analysis and to demonstrate the performance of the proposed approach. The maximum charging efficiency of the proposed topology during the overall charging period is 93.98%. Satisfactory performance is obtained from the measured results.

A High-Voltage AC/DC Resonant Converter Based on PRC With Single Capacitor as an Output Filter

One of the major drawbacks of high-ratio step-up transformers is the high value of their secondary-side capacitor. This value is reflected at the primary side, giving rise to a nondesirable one. There are some converters which include this capacitor in the topology and can cope with it, and even more, they need it. In particular, in high-voltage applications, we will find transformers with a large capacitance value since they use high-ratio step-up transformers. In this kind of applications, it is always interesting not to have inductors at the output filter, with single-capacitor filters being preferred instead. Thus, one of the simplest topologies is the parallel resonant converter (PRC) with a single-capacitor output filter. It can be controlled by the switching frequency and/or duty cycle, which makes zero voltage switching feasible in the power switches. In this paper, the PRC modeling and design and the experimental results are shown in a prototype delivering 3.5 kV and 260 W.

Magnetic control of DC-DC resonant converters provides constant frequency operation

A solution to operate DC-DC resonant converters at constant frequency is proposed. A variable inductor is used to achieve output voltage control and regulation without changing the switching frequency of the converter. The output voltage characteristic of the parallel resonant converter operating under this so-called magnetic control is briefly analysed. A 48 V input, 5 V output, 500 kHz, 25 W prototype is presented to prove the feasibility of the proposed control method.

Embedded Controlled Single Switch Parallel Resonant Converter for Induction Heating

Embedded Controlled Single Switch Parallel Resonant Converter for Induction Heating

Improved Modification of the Closed-Loop-Controlled AC-AC Resonant Converter for Induction Heating

A single-switch parallel resonant converter for induction heating is implemented. The circuit consists of an input LC-filter, a bridge rectifier, and a controlled power switch. The switch operates in soft commutation mode and serves as a high frequency generator. The output power is controlled via the switching frequency. A steady state analysis of the converter operation is presented. A closed-loop circuit model is also presented, and the experimental results are compared with the simulation results.

Implementation of HF Current Injection Technique for Three-Phase Converter AC-to-DC

This paper presents the high power factor operation of three-phase AC-to-DC resonant converter. The input three-phase uncontrolled diode bridge rectifier is followed by six pulse modified series parallel resonant converter. The high power factor of three-phase AC source is achieved by injecting high frequency (HF) current from output of the inverter to the input of rectifier. Therefore, HF modulation of AC input voltage of the three-phase line rectifier circuit is achieved. The output voltage of three-phase resonant converter is regulated by using variable frequency mode under 180°-wide gating pulse scheme. Detail analysis and design of HF current injection circuit is given for 3.5 kW output power operating at 300 kHz switching frequency.

Modeling and Performance Analysis of the DC/DC Series–Parallel Resonant Converter Operating With Discrete Self-Sustained Phase-Shift Modulation Technique

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A dynamic study of the dc/dc series–parallel resonant converter operating with a discrete self-sustained phase-shift modulation technique is presented. The study includes the synthesis of a suitable averaged large-signal dynamic model and the design of a nonlinear feedback controller based in the input–output linearization approach. The proposed controller and modulation type provide some outstanding features: zero-voltage switching operation for the whole load range, narrowed frequency variation range, fast transient response, and robustness in relation to external parameter variations. Experimental and simulation results are reported to validate the theoretical predictions and confirm the superior performance of the nonlinear controller when it is compared with a conventional linear controller. </para>

Analysis and Design of a Kind of Improved Parallel Resonant Converters

Traditional transformer in high-voltage power supplies has many disadvantages such as high turn’s ratio, large volume and great design difficulties. Parallel resonant converters (PRCs) are widely used in high-voltage power supplies. A kind of high-voltage circuit topology can be formed by combining PRCs and voltage-doubler rectifier, which is called parallel resonant dual voltage converters (PRDVCs). In PRDVCs both voltage-doubler rectifier and transformer can boost voltage, which reduced turn’s ratio and volume of the transformer, making it easier to produce. Thus it not only realizes the high-voltage output, but also realizes the miniaturization of high-voltage power supply. Three modes of the converters were researched and simulated. Converting conditions of three modes were given. At last, PRDVCs was used to design a 5000V/50mA high-voltage power supply. The waveforms and results of the experiment were given, which validated the feasibility of the converters and its conversion efficiency might be improved to 93%.

Modelling and analysis of split-capacitor push-pull parallel-resonant converter in normal mode

This paper presents a new model through which the operation of push-pull parallel resonant converters (PPRC) in normal mode can be analysed. The paper also introduces a technique whereby the converter, configured in a split-capacitor topology, can be operated either in buck or boost mode with a variable voltage gain. The three modes of operations of the converter with zero-voltage switching (ZVS) are achieved by generating a variable switching frequency through a variable phase-shift. The normal mode of operation, which is realised by switching the converter at its damped resonant frequency with zero phase-shift, is analysed in detail by deriving explicit analytical solutions for its performance and ZVS frequency. Experimental results of a 50 W prototype PPRC converter operated in the normal mode are presented and compared with simulations and theoretical results to prove the validity of both the proposed model and analysis. Impact of parasitic elements on performance has also been investigated and results indicate that they have only a little impact on the performance.

Low Cost Embedded Controlled Full Bridge LC Parallel Resonant Converter

Low Cost Embedded Controlled Full Bridge LC Parallel Resonant ConverterIn this paper the converter requirements for an optimum control of an electrolyser linked with a DC bus are analyzed and discussed. An electrolyser is a part of renewable energy system which generates hydrogen from water electrolysis. The hydrogen generating device is part of a complex system constituted by a supplying photovoltaic plant, the grid and a fuel cell battery. The characterization in several operative conditions of an actual industrial electrolyser is carried out in order to design and optimize the DC/DC converter. A dedicated zero voltage switching DC/DC converter is presented and simulated inside the context of the distributed energy production and storage system. The proposed supplying converter gives a stable output voltage and high circuit efficiency in all the proposed simulated scenarios. The adopted DC/DC converter is realized in a full-bridge topology technique in order to achieve zero voltage switching for the power switches and to regulate the output voltage. This converter has advantages like high power density, low EMI and reduced switching stresses. The simulation results are verified with the experimental results.

Modelling and analysis of split-capacitor push-pull parallel-resonant converter in normal mode

Modelling and analysis of split-capacitor push-pull parallel-resonant converter in normal mode

Children’s anti-scoliotic fixators with transcutaneous electronic activation

Conventional spinal implants are static and rigid structures which underpin the skeleton, not adapted to patient’s post-surgery evolution (e.g. growth in scoliotic children). A new active spinal implant uses mechanical energy from the patient’s body to perform an active, progressive dynamic correction. It is growth-compatible and can be extracted after completion of skeletal amendment. It is non-invasively controlled by means of a transcutaneous transformer. The core of the prosthesis is an internal hydraulic mechanism, which allows the appropriate corrective forces, bending moments and torques to be applied on the spine. The actions of the prosthesis on the skeleton can be periodically modified, under medical supervision, by activating several built-in, remote controlled micro-valves. The power and control signal to transiently activate the intracorporeal microvalves will be obtained by means of a PRC (parallel resonant converter) with a transcutaneous transformer. Telemetry is obtained by adding a slight oscillation in the frequency control circuit, resulting in an AM + FM modulated output signal. This signal is analyzed by a microcontroller in order to activate the selected intracorporeal microvalve. The new implant allows a progressive correction thanks to the non-invasive control of its modifiable geometry and its visco-elastic behaviour.

Mathematical model for split-capacitor push–pull parallel resonant converter in Buck mode

A technique is described whereby a split-capacitor push–pull parallel resonant converter (SC-PPRC) can be operated at a variable switching frequency with zero-voltage switching to provide either a lower (Buck) or higher (Boost) peak variable output voltage than that which would result in the conventional Normal mode. A comprehensive analysis of the SC-PPRC in the Buck mode is yet to be reported. All three modes of operation of the converter are detailed and a mathematical model is presented through which the performance of the converter during the Buck mode can be accurately predicted. The proposed Buck mode is facilitated by operating the converter essentially at a higher switching frequency than in the Normal mode. The higher switching frequency is generated by incorporating a negative and variable time delay into the switching period of the Normal mode. In contrast to both Normal and Boost modes, analysis of the converter in the Buck mode is different and complicated by the formation of two different resonant circuits during each switching cycle. The proposed mathematical solution for the Buck mode is accurate as validated by both simulations and measured results of a 150 W prototype Buck-operated SC-PPRC unit.

SOFT SWITCHING TECHNIQUE USING RESONANT CONVERTER FOR CONSTANT SPEED DRIVE

A zero voltage switched pulse width modulated series parallel resonant converter is presented in this paper. The performance of the converter for constant output voltage with the application of constant switching frequency but variable pulse width is analyzed. The converter operation is applied for motor load applications, where the load varies widely but the output voltage is fixed and is well regulated. Hence the speed of the motor is maintained constant.Experi-mental results are obtained to verify the theoretical results.

Analysis of Split-Capacitor Push–Pull Parallel-Resonant Converter in Boost Mode

This paper presents a new model that facilitates a comprehensive analysis of split-capacitor push-pull parallel resonant converter (PPRC) topology in three different modes. The three modes, named as normal, buck, and boost, are realized by operating the converter with a variable switching frequency, which is generated by modulating the damped resonant frequency with a variable phase-shift. The proposed modes allow the converter to operate with a variable voltage gain over a wide load range with zero-voltage switching (ZVS). In this paper, the operation and behavior of the converter in boost mode is analyzed in detail through derivation of explicit analytical expressions for voltage gain, ZVS frequency and other circuit variables. Experimental results of a 150 W prototype PPRC converter, controlled by the proposed technique, are presented and compared with simulations and theoretical results to prove the validity of both the proposed model and control technique. The results indicate that the gain of the prototype converter can be increased up to about 145% of the nominal voltage and the parasitic elements have only minor impact on the performance.

System efficiency of a DC/DC converter‐based wind farm

AbstractIn this paper, three DC/DC converter topologies are evaluated from an energy efficiency point of view regarding their suitability for the application in a DC wind farm grid. The three investigated topologies are the fullbridge (FB) converter, the single active bridge (SAB) converter and the series parallel resonant (LCC) converter. The energy efficiency of the three converter topologies is evaluated for different control strategies. It is found that the LCC and FB converters have the lowest losses of the three topologies. It is also shown that the wide range of operation creates problems for all three converters. The SAB converter has the largest increase in losses caused by the wide range of operation. The FB converter also has an increase in losses for this variable operating range, whereas the LCC converter has large stresses for the input and output filters. By considering some further factors, such as the contribution to the energy production cost, the design and the control of the converters, the FB converter is found to be a suitable choice for wind farm application. Copyright © 2007 John Wiley &amp; Sons, Ltd.