Push-pull Converter Research Articles

High Input Power Factor High Frequency Push-Pull DC/DC Converter

To maintain high efficiency and high power density increased switching frequency is the primary path. The push-pull converter used as ac-dc converter is very suitable for low and medium power application. High efficiency, low switching loss and high power density are the predominance of this application Increased switching frequency gives high power density, reduces size of components and this give simplicity of the circuit. Main aim of proposed topology is to obtain isolated dc voltage from ac voltage input with reduced switching losses and high input poer factor. This topology uses push-pull converter with z-source to improve input power factor and ,50 khz switching frequency with ferrite core transformer to obtain high poer density. This converter topology is suitable for obtaining low voltage ,high current source from a high voltage ,low current AC source. This would find application in high current battery bank charging, heating of the bearings, led lightings and

A Highly Efficient and Reliable Power Scheme Using Improved Push-Pull Forward Converter for Heavy-Duty Train Applications

Electronically controlled pneumatic (ECP) brake systems have become popular in heavy-duty train applications because of their advantages, which include shorter stopping distances, improved handling, and less brake-shoe and wheel wear. In ECP brake systems, an improved power supply is required to support efficient and reliable operations. In this paper, we propose a new power converter for ECP brake systems, which is derived from a conventional push-pull converter. As opposed to conventional push-pull converters, we insert a clamping capacitor into the proposed circuit. This clamping capacitor simultaneously enables a greater number of operation modes for the proposed converter and absorbs the voltage spikes in the switch. The proposed converter is more suited for ECP brake applications that require high power, low voltage ripple, and high impedance. We theoretically analyze the proposed converter, and present the design guidelines. Further, we discuss the modeling and control aspects. We demonstrate the operations of the proposed model by performing both simulations and experiments.

Removal of electrocardiogram distortion in portable high-power medical device

In this study, we propose a method to remove bio-signal distortions generated when the power is at transient condition in a high-powered portable medical device. To verify the method, three units were designed that consists of a main control unit, bio-signal measurement unit, and power unit. Also, each units were separated with galvanic isolation. For stable operation at the surge condition, the power unit was composed using push-pull converter topology. The design has been examined in both transient and steady state of the operating conditions. The experiment result shows that galvanic isolation between each units was efficient in high-powered potable medical device.

Small signal modelling and implementation of push-pull based inverter with parasitics

Original scientific research The proposed PWM switch modelling technique is a simple method for modelling push-pull based single phase inverters operating in continuous conduction mode. In the design process of converters it is desirable to assess as many critical design parameters and parasitic effects by simulation as possible, since the control is hard to tune after fabrication. The main advantage of this method is its versatility and simple implementation. Furthermore, the introduced model also includes parasitic elements of the components to better estimate the converter behaviour. The resulting circuit is a time averaged model where all currents and voltages correspond to their averaged values. The validity of this model is verified by the given experimental results for a specified design example. This modelling technique helps to design the inverter effectively and better choosing the controller component values to achieve a good dynamic response. Finally, current mode controlled push-pull converter is simulated and compared with proposed modelling technique where a good accordance between them is revealed. Simulation analysis is done by Matlab 9 and Psim 6 software. The overall modelling estimation error was lower than 5 %.

A Switching Control Strategy for Single- and Dual-Inductor Current-Fed Push–Pull Converters

A switching control strategy is proposed for single- and dual-inductor current-fed push-pull converters. The proposed switching control strategy can be used with both current-fed push-pull converters with an active voltage doubler rectifier, or active rectifier, in the secondary-side of the isolation transformer. The proposed switching control strategy makes turn-on and turn-off processes of the primary-side power switches zero-voltage switching and zero-current switching, respectively. The soft-switching operation of the single- and dual-inductor push-pull converters, with both types of active rectifier, is explained. Simulation and experimental results are provided to validate soft-switching operation of the current-fed push-pull converters with the proposed switching control strategy.

Autonomous Polyphase Current-Fed Push–Pull Resonant Converter Based on Ring Coupled Oscillators

This paper presents an autonomous polyphase current-fed push-pull resonant converter without the need of monitoring and controlling its phase delays. Although the method is valid for multiple phases, a three-phase system is studied to show that accurate 120° phase shift can be realized by coupling three identical magnetic coils of a resonant converter with zero voltage switching (ZVS). Unlike the conventional converters, the proposed converter achieves a full-autonomous operation with automatic startup, full resonance at ZVS, and accurate dynamic balancing between the phases without any additional detection and control. A prototype of a three-phase system operating at 73.5 KHz has been built, and both simulation and practical results have demonstrated that the proposed converter can generate good quality sinusoidal waveforms with ZVS operation and precise phase delays. The proposed converter can be used for polyphase inductive power transfer systems where a generation of a rotating/travelling magnetic field is required.

Bidirectional Flyback-push-pull Dc-dc Converter

This paper presents a bidirectional flyback- push-pull dc-dc converter. The main characteristics of the proposed converter are galvanic isolation by high- frequency transformers, high efficiency, reduced number of components and low current ripple at both the input and output DC power supplies. The typical applications include isolated bidirectional interface between two low voltage DC buses, where low current ripple is required. The study presents theoretical analysis, design example and experimental data for an 800 W, 80 VDC input, 160 VDC output and 50 kHz of switching frequency, on the laboratory prototype. The measured performance and theoretical predictions were in good agreement.

Optimized Adaptive Perturb and Observe Maximum Power Point Tracking Control for Photovoltaic Generation

The power extracted from PV arrays is usually maximized using maximum power point tracking algorithms. One of the most widely used techniques is the perturb & observe algorithm, which periodically perturbs the operating point of the PV array, sometime with an adaptive perturbation step, and compares the PV power before and after the perturbation. This paper analyses the most suitable perturbation step to optimize maximum power point tracking performance and suggests a design criterion to select the parameters of the controller. Using this proposed adaptive step, the MPPT perturb & observe algorithm achieves an excellent dynamic response by adapting the perturbation step to the actual operating conditions of the PV array. The proposed algorithm has been validated and tested in a laboratory using a dual input inductor push-pull converter. This particular converter topology is an efficient interface to boost the low voltage of PV arrays and effectively control the power flow when input or output voltages are variable. The experimental results have proved the superiority of the proposed algorithm in comparison of traditional perturb & observe and incremental conductance techniques.

Novel isolate DC-DC converters with current circulating circuitfor electronic/hybrid car and UPS

Full-bridge, Push-Pull, Flyback and Forward converters are generally used for electronic/hybrid car and UPS(Uninterrupted Power Supply). In this paper, we proposed novel Full-bridge, Push-Pull, Flyback and Forward converters. In the design topologies, the proper inductor was added in order to make the circulating current even during dead time period, so that we can achieve the better properties such as higher efficiency, cheaper price, with same output properties as the conventional converters. The proposed topologies simulated by PSpice.

A Switched-Reluctance Generator With Interleaved Interface DC–DC Converter

This paper presents the development of a wind switched-reluctance generator (SRG) with interleaved interface dc-dc converter. First, the power circuit and control scheme of the SRG are properly designed. The hysteresis current-controlled pulse width modulation (PWM) scheme is designed to achieve good winding current tracking control, and the robust voltage control scheme is developed to yield well-regulated dc output voltage under varying prime mover driving speed and load conditions. Moreover, the voltage regulation and the developed power performances of SRG are further enhanced using the proposed commutation shift approach. Next, an interleaved current-fed push-pull interface dc-dc converter with two modules is developed to establish the boosted common dc bus voltage of a dc microgrid from the SRG output having fault-tolerant capability. The rating analysis and circuit component design are conducted in detail. Similarly, well-regulated voltage with lower ripples is also yielded via the properly designed schematic and control scheme.

Impulse Commutated Zero-Current Switching Current-Fed Push–Pull Converter: Analysis, Design, and Experimental Results

Impulse commutated current-fed push-pull (ICCPP) converter has been analyzed and designed. The topology maintains zero-current switching (ZCS) of the semiconductor devices. Variable frequency modulation has been adopted to regulate load voltage and achieve ZCS over variable input voltage. At fixed input voltage, ZCS and load voltage are load independent. Natural clamping of devices is achieved via impulse commutation. Push-pull converters have only two devices with common ground with source requiring simple gate drive circuitry. A comprehensive study of the proposed converter, including steady-state analysis and design, has been reported. A 500-W prototype was developed in the laboratory to evaluate and demonstrate the performance of the converter.

ANALYSIS AND DESIGN OF DIGITAL PID CONTROLLER FOR PUSH-PULL DC/DC CONVERTER

This paper presents a method for the design and simulation of digital controller based on Field Programmable Gate Array (FPGA) technique for DC/DC Push-Pull converter operating in continuous conduction mode. The Push-Pull converter is simulated using PSIM and controller is designed using MATLAB with the help of XILINX tool box. Using SimCoupler module in MATLAB, co-simulation of PSIM and MATLAB is obtained. The performance of FPGA based PID controller strategy is validated for line and load variations.

Naturally Clamped Snubberless Soft-Switching Bidirectional Current-Fed Three-Phase Push-Pull DC/DC Converter for DC Micro-Grid Application

A current-fed three-phase push-pull bidirectional dc-dc converter is proposed with unique features of natural zero current commutation and natural device voltage clamping. The proposed topology is suitable for uninterruptible power supply, storage, renewable energy sources, and interfacing two dc buses of 48- and 380-V dc buses in a dc microgrid. The proposed converter implements a novel and innovative modulation that results in natural commutation with zero current switching (ZCS) and device voltage clamping of low voltage side (LVS) current-fed devices, and zero voltage switching (ZVS) turn-on of high voltage side (HVS) voltage-fed devices. It eliminates the use of passive/active clamp circuits to mitigate the turnoff voltage spike across the devices, a traditional problem associated with current-fed topologies. Additionally, the higher ripple frequency reduces the volume of the transformer and the input inductor, making it suitable for high-power applications. The detailed modulation scheme, steady-state operation, and analysis, design, and soft-switching conditions have been explained. Simulation results obtained using PSIM 9.3 have been illustrated to verify the modulation, analysis, and proposed design. Experimental results have been demonstrated for full load (1 kW), half-load (500 W), and 20% load conditions on a proof-of-concept hardware prototype to validate the claims and performance. The efficiency is plotted against various load conditions for a wide range of battery voltage variation (40-59 V). Peak efficiencies of 95.8% and 93.8% are obtained at half-load condition for an input voltage of 59 V and nominal voltage (48 V), respectively. The experimental results for battery charging (reverse direction) using dual phase-shift plus pulsewidth modulation are given. The ZVS of HVS switches and the synchronous rectification of LVS active switches are shown through experimental results.

Current-Fed Soft-Switching Push–Pull Front-End Converter-Based Bidirectional Inverter for Residential Photovoltaic Power System

Photovoltaic (PV) residential power system is an important application of renewable energy. The parallel-connected configuration of PV modules rather than the series-connected configuration become popular considering the safety requirements and making full use of the PV generated power for the PV residential generation system. In this paper, a novel soft-switching current-fed push-pull front-end converter-based inverter is proposed. Push-pull converter has only two primary devices with common ground to supply and results in simple and reduced gating requirement. The device voltage is clamped naturally by secondary modulation without active clamping circuit or passive snubbers. Zero-current switching of primary devices and zero-voltage switching of secondary devices is achieved. Soft-switching is inherent owing to proposed secondary modulation, load independent, and is maintained during wide variation of input voltage and power transfer capacity, and thus is suitable for PV applications. A 250-W laboratory prototype of the converter is built and tested to demonstrate the converter performance over wide variations in input voltage and output power for PV applications.

Current-Fed Flyback Push-Pull DC-DC Converter Based on Three-Phase Transformer

Three-phase current-fed flyback push-pull dc-dc converter is proposed in this paper, which is a new circuit topology putting into practice based on current-fed flyback push-pull dc-dc converter. Structure is simplified; cost is cut down; efficiency and reliability are improved all by the high frequency three-phase transformer technique that carries out functions of flyback transformer as well as push-pull transformer at the same time. Three-phase transformer can be separated into relatively independent functions of flyback transformer and push-pull transformer with the reluctance produced by the magnetic gap in the central phase; the flyback transformer produces only common-mode flux in the magnetic circuit of push-pull transformer and does not influence its output signal; the magnetic flux in push-pull transformer is blocked by the magnetic gap and can only flow through the outer magnetic loop. Investigational device is designed; static and dynamic characteristics are observed and test results are verified by the experimentation.

Efficiency Optimized Single-Stage Reconfigurable DC/DC Converter for Hybrid and Electric Vehicles

This paper proposes a single-stage reconfigurable topology for an isolated dc/dc converter that supplies the 12 V power net from high voltage (HV) battery pack in hybrid and electric vehicles. The proposed topology solves the problem of reduced converter efficiency in the upper range of HV battery voltages. The converter is based on a zero voltage transition (ZVT) phase shift (PS) full bridge dc/dc converter that is during its operation, depending on the instantaneous value of battery voltage, reconfigured into a push-pull converter. The more efficient ZVT PS configuration covers the upper range of input voltages whereas the hard-switching push-pull configuration covers the lower, less significant range. The ZVT PS configuration, due to tighter voltage range, operates with reduced turn-off losses, significantly decreased circulating current in the freewheeling period as well as improved efficiency of the rectifier stage. The point of reconfiguration is chosen to maximize the average efficiency according to the histogram of HV battery voltage during a typical driving cycle. The operation of the proposed converter and the efficiency improvement are validated experimentally.

Smart Switching Power Supply with Input Voltage Waveform Correction

The technology of smart control rectifier is introduced in this paper, in which the harmonic currents in power system is reduced and the voltage waveform is compensated. The voltage waveform in power system is measured by microcontroller, and is compared with the standard sinusoidal voltage waveform and the error voltage is obtained which contains the information of harmonic current waveform. The error voltage is employed to control the input current of the rectifier, and the reverse components of harmonic current is involved in the power side current of the appliance, by this means to get rid of some of the harmonic currents in power grid. Harmonic current will produce a voltage drop on the resistance in power transmission line to make the voltage waveform distortion happen; and the reduction of the harmonic current will shrink the distortion of voltage waveform. Taking a capacitive soft switching flyback push-pull converter as an example, the experimental circuit and the testing system are designed; the software programming and circuit debugging are accomplished. The experimental results show that the smart control rectifier can absorb harmonic currents from the power grid when operating in rectification, and to get the input voltage waveform corrected.

English

The internet and the demand for online connectivity are fuelling the energy consumption in Data Centers. According to DataCenterDynamics 2012 Global Census, the power requirements grew by 63% globally to 38GW, up from 24GW in 2011. The census estimated a further rise of 17% to 43GW in 2013. It is important that this growing demand for energy is met by the power supply from renewable energy sources. The Power SupplyDistribution System for FutureData Centers is shifting towards DC Architecture from existingAC architecture. In this paper, 380V DCis considered as the transmission voltage and 48 V DCas the distribution voltage inside the Data Centers. An efficient 380V to 48V DC-DC buck converter withless switching and thermal losses can reduce the cooling requirements of the Data Center. In this directiona suitableconfiguration is selected by comparingTwo- Stage, Half- Bridge, Push-Pull and Full-Bridge buck converters based on efficiency and power loss analysis.

Comparative Study of Rectifier Topologies for Quasi-Z-Source Derived Push-Pull Converter

Quasi-Z-source derived push-pull converter is a new topology intended for energy harvesting from renewable energy sources. Use of the topology shows that currents in the input and output parts strongly depend on the implementation of the output rectifier. This paper presents a comparative study and an experimental evaluation of the four output rectification stages. Analytical expressions for the voltage and current stress of rectifier components are presented. Experimental verification with the 400 W prototype was performed in the input voltage range of 40 V to 400 V at 400 V output voltage. Efficiency and duty cycle of active state, i.e. the DC gain characteristic, were measured in that range. Experimental waveforms for each topology are presented. Waveforms were measured at the input voltage 80 V, i.e. at the DC gain factor equal to 5. DOI: http://dx.doi.org/10.5755/j01.eee.20.6.7264

Research on High Efficiency Non-Isolated Push-Pull Converters with Continuous Current in Solar-Battery Systems

In order to improve the output efficiency of solar cells and to extend the life span of batteries, the input currents of converters are required to be continuous. If low output voltage ripple is required at the same time, it is obvious that the application of basic two-order converters (such as Buck and Boost derived converters) will not be good enough. In this paper, a lot of non-isolated push-pull converters (NIPPCs) with continuous current will be introduced due to their lower current stress, higher efficiency and better EMC performance. By decomposing the converters into push-pull cells, inductor and free-wheeling diodes, two families of NIPPCs based on single inductor and coupled inductor separately are systematically generated. Furthermore, characteristics analyses for some of the generated converters are also shown in this paper. Finally, two prototypes based on the corresponding typical topologies are built in the lab to verify the theoretical outcomes.