Quasi-resonant Converter Research Articles

On the Influence of Fractional-Order Resonant Capacitors on Zero-Voltage-Switching Quasi-Resonant Converters

This paper focuses on the influence of the fractional-order (FO) resonant capacitor on the zero-voltage-switching quasi-resonant converter (ZVS QRC). The FO impedance model of the capacitor is introduced to the circuit model of the ZVS QRC; hence, a piecewise smooth FO model is developed for the converter. Numerical solutions of the converter are obtained by using both the fractional Adams–Bashforth–Moulton (F-ABM) method and Oustaloup’s rational approximation method. In addition, the analytical solution of the converter is obtained by the Grünwald–Letnikov (GL) definition, which reveals the influence of the FO resonant capacitor on the zero-crossing point (ZCP) and resonant state of the converter. An experimental platform was built to verify the results of the theoretical analysis and numerical calculation.

Power flow and reliability analysis of a non-isolated PV/grid connected quasi resonant converter for off-board EV charging station

ABSTRACT Growing awareness of greenhouse gas emissions and exhaustion of fossil fuels leads to the adoption of electric vehicles (EVs). However, the major limitations with respect to EV technology are the driving range and charging time. Also, the proliferation of EVs overloads the power grid and paves the way of incorporating renewable energy sources and energy storage devices. The use of multiple sources necessitates the deployment of compact, low-cost, and high-power electronic converters. This paper proposes a novel configuration of a Multi-Source Non-Isolated Quasi-Resonant Converter (MSNQRC) to overcome the limitations in the charging infrastructure. Due to the presence of a quasi-resonant network, the proposed MSNQRC with a single switch can achieve high voltage gain even at low-duty cycles, provide continuous current and low voltage stress. In addition, this paper elaborates on the parametric design of the converter along with PV modeling based on load ratings and the reliability research of MSNQRC by analysing component failures. A prototype model of 300W is built to verify the efficacy of the designed converter model. The results thus obtained validate the designed model and prove that the proposed system can be used for off-board battery charging systems.

Quasi-Resonant Converter for Electric Vehicle Charging Applications: Analysis, Design, and Markov Model Use for Reliability Estimation

This article presents a quasi-resonant converter (QRC) with multiple sources. A QRC has many benefits, such as high gain, constant current, and nominal voltage stress on MOSFET, with an up to 49% duty cycle with fewer switches. These features of the converter make it suitable for electrical vehicle (EV) off-board charging, which requires significant voltage gain. As the switch operates under soft switching condition, the converter has reduced power loss, improved efficiency, and increased reliability. To reduce grid dependency, the suggested QRC is housed with a grid and PV at the input ports. The proposed converter is modeled using mathematical equations and examined using the MATLAB platform under different operating conditions. In this work, analysis of the steady state, along with components design, estimation of the voltage and current stresses, are addressed. Further, the reliability of the QRC based on the probability of components failure is carried out using the Markov model. The hardware results are observed to validate the design, operation, efficiency, and suitability of the proposed QRC for EV off-board charging applications. A 400-watt test rig is designed to assess the performance of QRC.

Grid connected PV based on quasi resonant zeta converter with Harris Hawk optimization algorithm for the implementation of PI controller

Grid connected PV based on quasi resonant zeta converter with Harris Hawk optimization algorithm for the implementation of PI controller

A Passivity-Based PI Control of Quasi-Resonant Buck Converter

In order to guarantee the stability of quasi-resonant converters, the zero-current switching quasi-resonant buck topology is supplied with a PI passivity-based controller in this study. An adequate and full-order model with constant steady-state solutions is generated, via the interconnection of port-Hamiltonian systems based on the principal structure of the converter. The passivity-based approach is employed to complete the control design, and numerical validation results are provided to ensure performance estimations.

A new implementation of PI controller for quasi-resonant converters

The main contribution of this paper is to increase the operating range of quasi-resonant DC-DC converters through the implementation of a PI controller, considering the relationship between the duty cycle and switching frequency. Quasi-resonant converters use a soft switching method where the power devices switch at zero voltage or zero current, resulting in low switching loss and high power density. The controller design is carried out by applying the evaluation of the power stages in the topology with the aim to ensure soft switching commutation. Simulation results are presented to illustrate the features of the proposed estimation.

Quasi-Resonant Half-Wave Buck Converter with Non-Isolated High Side Switching Techniques

Power density of the power converters became one of the most important parameters in many applications. Power density is increased by reducing the losses through use of better performing components and circuit topologies. It can be increased further by reducing the size of filter components through increasing the switching frequency. In hard-switching converters however, losses due to switching will eventually render this method not applicable. Instead, resonant converters are utilized in many high-frequency switched power supplies. Soft-switching feature of these converters provide increased efficiency due to decreased switching losses. Such converters exploit the resonance of the specific inductors and capacitors in the circuit called as resonant tank elements. Resonance behavior is used in order to eliminate turn-on or turn-off losses. Existing power converter topologies can be modified to create the resonance during switching period. Such converters are called as quasi-resonant converters. This paper presents analysis and design of Zero Current Switching (ZCS) half-wave quasi-resonant buck converters. In this topology, high-side switching is required. Two different non-isolated high-side switching techniques are utilized. Experimental results are obtained for light load to full load operation. Both techniques are compared in detail.

Research on Equalization Strategy Based on Credibility Factor Inference for Lithium-Ion Battery Packs

In this paper, a two-stage equalization topology based on Zero-Voltage Switching Quasi-Resonant Converter (ZVS QRC) is proposed to solve the problems of long equalization time and low energy utilization of series lithium-ion battery packs. The equalization topology is divided into two forms: intra-group and inter-group, ZVS QRCs are adopted in both intra-group and inter-group, which can equalize any single cell within a group, and the equalization circuit within each pack can equalize simultaneously, which greatly reduces the equalization time, and reduces the switching loss during the equalization process by introducing quasi-resonant circuit to improve the energy utilization. Taking the State of Charge (SOC) as the equalization target, a group equalization strategy based on the Credibility Factor (C-F) inference model is proposed. The strategy defines the SOC unbalance degree of a single battery, gets the group unbalance degree according to the C-F inference model, and gets the group equalization state from the unbalance degree, to control the group for equalization. Matlab/Simulink software is used to build the model and simulate it. The experimental results demonstrate that the proposed topology saves approximately 25% of the equalization time compared to the traditional Buck-Boost group equalization topology. Under the same static and charge/discharge conditions, the equalization time is reduced by about 21% and the energy utilization is improved by about 6% after using the C-F inference model for equalization compared to the fixed-threshold method.

Robust nonlinear control of a quasi‐resonant DC‐DC converter with turn‐on and turn‐off zero current switching

In this paper, a new robust control strategy is proposed to regulate the output voltage of a quasi-resonant converter. The proposed approach completely eliminates the switching losses and the electromagnetic interferences due to high current changing rates. The circuit structure is simple and affordable and does not have many auxiliary switches. The regulated output voltage of a buck converter must be robust to input voltage variations. Moreover, the controller must be robust to the circuit parameter uncertainties. In this paper, a new control strategy with nonlinear structure is used with the advantage of robustness, and turn-on and turn-off zero current switching. The robustness of the converter to the input voltage variations and the parameter uncertainties is investigated. The new proposed control strategy can be implemented using different controller types. Therefore, a comparison between the proposed nonlinear controller and a conventional PI controller, which is most widely used in practice, is performed. The simulation results show the efficiency and robustness of the proposed method. Finally, the simulation results are verified by the experimental tests.

Fixed-Frequency Current-Fed LCL Series Resonant Soft-Switching Converter With Capacitive Doubler

Electrification of power take-off (ePTO) system is an effective way to minimize the fossil fuel consumption from heavy duty electric vehicles, where a high gain dc/dc converter is needed to integrate PV/fuel-cell. Popular high-gain dc/dc converters such as PWM type, clamped and unclamped quasi-resonant converters cant serve such applications as they fail to achieve high-efficiency, wide load and input voltage range for soft-switching, constant switching frequency and high transformer utilization (TUF) simultaneously. In this paper, a LCL series resonance based high-gain load resonant dc/dc converter is proposed to eliminate the above-mentioned drawbacks. A series resonant tank in the converter is able to adapt tank current in proportion to load demand leading to minimum losses and high TUF. Further, energy is stored in the series and parallel resonant inductors, in proportion to load demand and constant load voltage respectively, ensures soft-switching of the converter through full load to light load conditions. On the other hand, proposed converter operates with constant switching frequency to adopt simple PWM modulation to regulate load voltage against input and load disturbances. This paper presents operation, analysis, modeling and design of the proposed converter. Hardware setup has been mounted and tested to verify he proposed theory.

Modeling of Buck ZVS Multiresonant DC-DC Converter Using Bond Graphs

Pulse width modulated (PWM) converters are suffering from poor efficiency due to high switching losses. quasiresonant converters with the help of resonance phenomenon can come to the rescue of PWM converters. There are certain problems even with the quasiresonant converters. Problems with quasiresonant converters such as parasitic oscillations and high voltage stress can be resolved with the help of multiresonant converters. Appropriate modeling technique is needed to accurately represent the physical system. The multiresonant converters along with electrical systems are involved in magnetic and thermal systems. For this kind of systems, the appropriate modeling is bond graph. In this piece of work, buck ZVS multiresonant converter is taken to model using bond graphs. The large signal bond graph model is created. In MATLAB/SIMULINK for state variables the created bond graph model is simulated. The findings obtained are checked with PSIM simulated results and experimental results. The comparison of model and experimental results prove the model’s accuracy.

Comparison of voltage source converters and Z-source converters for electric vehicles

Voltage source and current source converters are used in industrial applications as either boost or buck converters for a defined power flow direction. These operational modes limit these converters to be utilized on their own in hybrid and electric vehicle (EV) applications. Z-source (impedance source) converters, on the other hand, have the capability to be operated as buck and boost converters to have a wide range of output levels. The boost ratio of the direct current link voltage of a Z-source converter is set by short-circuiting the phase legs of the converter and defining the overlap duration at each switching period. In order to have the optimum efficiency with the lowest possible total harmonic distortion, a modified space vector pulse width modulation method with an impedance network could be selected for closed-loop control of the quasi-resonant Z-source converter to drive permanent magnet synchronous motors (PMSMs). In this study, closed-loop vector-controlled drive systems built with two-level and three-level boosted voltage source converter topologies and two- and three-level quasi Z-source converters for field-oriented control of a PMSM in EV motor drive applications were compared under constant motor speed–constant load, constant speed–variable load and variable speed–constant load operating conditions.

Onboard Energy Storage System Based on Interleaved High-Conversion-Ratio Quasi-Resonant Converter With Small Characteristic Impedance

An onboard energy storage system (OESS) withfast-energy-exchange capability is needed to enable future grid-to-vehicle (G2V) and vehicle-to-grid (V2G) operations. To facilitate the fast energy exchange, the OESS normally interfaces between a high voltage (HV) bus on the grid side and a low voltage (LV) bus on the vehicle side. The HV bus can be up to 1200 V, while the LV bus is as low as 48 V, which means a high conversion ratio is needed. Resonant converters are commonly used for OESS and designed with large characteristic impedance for wide-range output power and zero-voltage-switching operation. However, such a design leads to large volume and complex customization of the magnetic components. In this paper, a high-conversion-ratio OESS is proposed, which is based on interleaved quasi-resonant converters with small characteristic impedance. The resonant converters are of modular design with a small characteristic impedance to achieve small volume, low cost, and simple customization. Interleaved in LV-side-parallel and HV-side-series configuration, a high conversion ratio can be achieved. Moreover, modulated in quasi-resonant operations, all the switches can realize soft switching even at light load conditions for high efficiency. Burst control for output regulation is implemented in each modular quasi-resonant converter, while interleaved control is implemented between them to minimize the current ripple. The proposed design and control are validated by a compact 5 kW prototype with a charging/discharging current of 100 A, high power efficiency of 98.91%, a high power density of 3.86 W/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> , and high-conversion-ratio (up to 20: 1) power flow between a 1000 VDC HV bus and a 48 VDC LV bus.

Quasi resonant converter for autonomous power supply

Quasiresonant converters (QRCs) are increasingly being used in autonomous power supply systems. These converters are efficient, have small dimensions, and operate stably when the load changes. This study is devoted to the development of a zero-current switching QRC with improved characteristics. The main advantages of this QRC are a wide range of regulation and a low level of output voltage ripple. These advantages are achieved by the recuperation of excess energy due to a transistor shunting the primary winding of a transformer. In this work, a mathematical model of advanced QRC (AQRC) is developed, and the quantitative relationship between the parameters of the AQRC power circuit elements is established. In addition, the electromagnetic processes occurring in the AQRC are studied on the Simulink model. Moreover, the AQRC characteristics for various operating modes are studied, and the rational parameters of its components are determined. Then, an AQRC prototype is created. The tests of the prototype are in good agreement with the models. Results show that the AQRC allows for the adjustment of the output voltage ranging from 0 to 100% of the rated value and has a standard level of electromagnetic compatibility.

Development of 2-kW DC Power Supply for Tetrode-Based RF Amplifier

This article comprises a design, simulation, development, and testing of 500-V, 4-A dc power supply based on the zero voltage switching (ZVS) scheme. Resonant converters have many variants. In this article, quasi-resonant converter (QRC)-ZVS-half bridge-constant frequency type has been used which is generally employed for fixed load application, but in the proposed novel design, tank circuit has been designed in such a way to keep ZVS instant intact even in the case of variable load conditions. Four modules of resonant buck converter of 125 V, 4 A each, have been connected in series to obtain the desired output. The proposed power supply has four sections, such as 12-pulse rectifier transformer, rectifier unit, resonant buck converter followed by a filter unit. A simulation study of the proposed topology was carried out using Power Simulation (PSIM) software. A hardware model of 2 kW consisting of four modules was implemented and tested on resistive load for different scenarios required by control grid (CG) biasing application for tetrode tube; results were analyzed for various modes of operation and ZVS profile was observed for each mode of operation depicting the intact ZVS instant with variable load. Power supply efficiency was measured using an energy analyzer which comes out to be ~90%.

A novel modelling and control strategy for a full-wave ZCS quasi-resonant boost converter for a PV-based battery charging system

In this paper, a novel modelling and control strategy is proposed for a DC-DC quasi-resonant boost converter utilised in a photovoltaic-based (PV-based) battery charging system. The MOSFET switch of the boost converter is operated at zero current using a resonant tank, providing soft-switching functionality, to reduce the switching losses experienced by conventional boost converters. The principles of operation of the utilised converter are analysed in detail and a characteristic function representing the model of quasi-resonant converter circuit is derived. This model is then used to design and implement a frequency control technique, which will maintain a constant DC voltage at the output stage of the converter to charge the battery. Simulation studies are conducted using MATLAB Simscape toolbox to evaluate the performance of the proposed controller. Simulation results validate the soft-switching functionality of the converter and its ability to reach and maintain the desired output voltage for charging a battery load in the presence of varying input voltage generated by a PV system with intermittent nature.

A novel modelling and control strategy for a full-wave ZCS quasi-resonant boost converter for a PV-based battery charging system

In this paper, a novel modelling and control strategy is proposed for a DC-DC quasi-resonant boost converter utilised in a photovoltaic-based (PV-based) battery charging system. The MOSFET switch of the boost converter is operated at zero current using a resonant tank, providing soft-switching functionality, to reduce the switching losses experienced by conventional boost converters. The principles of operation of the utilised converter are analysed in detail and a characteristic function representing the model of quasi-resonant converter circuit is derived. This model is then used to design and implement a frequency control technique, which will maintain a constant DC voltage at the output stage of the converter to charge the battery. Simulation studies are conducted using MATLAB Simscape toolbox to evaluate the performance of the proposed controller. Simulation results validate the soft-switching functionality of the converter and its ability to reach and maintain the desired output voltage for charging a battery load in the presence of varying input voltage generated by a PV system with intermittent nature.

Методика оптимизации энергомассовых характеристик системы электропитания геостационарного космического аппарата

This article determines a methodology to maximize a specific power of the electrical power system of a geostationary spacecraft, using the EPS simulation model. A typical (for GEO spacecraft) fully-regulated EPS structure is considered. The advantages of using the full bridge quasi-resonant converters with galvanic isolation are considered. The results of the energy efficiency estimation of power converters at various ranges of input voltages, as well as the criteria and conditions for calculating the positive energy budget of a GEO spacecraft are presented. The application of the EPS simulation model is shown and the results of optimization of the proposed EPS energy and mass characteristics for 6 and 13 kW payloads are described

Passivity‐based controllers for ZVS quasi‐resonant boost converter

There is a consistent demand for reliable, efficient, small-sized, and light weight power supply for electronics devices. To meet the aforesaid requirements, Quasi Resonant converters are being used due to low switching losses, high efficiency, small size and weight. With these motivations, in this paper, two different methodologies of passivity-based controllers namely (EL-PBC and PCH-PBC) are proposed for Zero Voltage Switching Quasi Resonant (ZVS-QR) boost converter to regulate the output voltage. First, the Euler-Lagrange (EL) formulation is used to derive state-space equations for ZVS-QR boost converter under different operating modes and then, average state-space model is developed using generalized state space average (GSSA) technique. In order to improve the dynamic performance of the ZVS-QR boost converter, the aforesaid passivity-based controllers are designed and its stability analysis is carried out. The entire system is developed with Sim Power System toolbox of MATLAB software and validated through OP-5142 real time simulator. Steady state and dynamic performances are examined under several operating conditions. It is observed that the passivity-based controllers of the paper achieve robustness against the uncertainties at the input and the load side. It is compared with benchmark PI controller as well.

High Step-Up Quasi-Resonant Converter Featuring Minimized Switching Loss Over Wide Input Voltage Range

This article proposes a high step-up quasi-resonant converter that minimizes switching loss over a wide range of input voltages. By employing a bidirectional switch and corresponding switching modulation, the proposed converter achieves the main switch with almost zero voltage, and therefore incurs very little switching loss at all active switches. Moreover, no instantaneous reactive current flows through the circuit under wide variations of input voltages and loads. The duty cycle of primary-side switches is fixed to 0.5; then, the input and clamp capacitor voltages become identical, and thereby the following resonant capacitor voltages remain in balance. As a consequence, the proposed converter becomes compact and achieves high boost-ratio and high efficiency over a wide range of input voltages. The operating principle of the converter is presented along with its design procedure. 400-W/380-V prototype of the proposed converter has been implemented and tested at 40-60 V to verify its effectiveness.