Showing papers on "Buck–boost converter published in 2014"
TL;DR: In this paper, a single-switch high step-up nonisolated dc-dc converter integrating coupled inductor with extended voltage doubler cell and diode-capacitor techniques is presented.
Abstract: The high-voltage gain converter is widely employed in many industry applications, such as photovoltaic systems, fuel cell systems, electric vehicles, and high-intensity discharge lamps. This paper presents a novel single-switch high step-up nonisolated dc-dc converter integrating coupled inductor with extended voltage doubler cell and diode-capacitor techniques. The proposed converter achieves extremely large voltage conversion ratio with appropriate duty cycle and reduction of voltage stress on the power devices. Moreover, the energy stored in leakage inductance of coupled inductor is efficiently recycled to the output, and the voltage doubler cell also operates as a regenerative clamping circuit, alleviating the problem of potential resonance between the leakage inductance and the junction capacitor of output diode. These characteristics make it possible to design a compact circuit with high static gain and high efficiency for industry applications. In addition, the unexpected high-pulsed input current in the converter with coupled inductor is decreased. The operating principles and the steady-state analyses of the proposed converter are discussed in detail. Finally, a prototype circuit is implemented in the laboratory to verify the performance of the proposed converter.
282 citations
TL;DR: The proposed active-network converter with switched-capacitor technique can achieve high voltage gain without extremely high duty ratio and the voltage stress of the active switches and output diodes is low.
Abstract: The voltage gain of traditional boost converter is limited due to the high current ripple, high voltage stress across active switch and diode, and low efficiency associated with large duty ratio operation. High voltage gain is required in applications, such as the renewable energy power systems with low input voltage. A high step-up voltage gain active-network converter with switched-capacitor technique is proposed in this paper. The proposed converter can achieve high voltage gain without extremely high duty ratio. In addition, the voltage stress of the active switches and output diodes is low. Therefore, low voltage components can be adopted to reduce the conduction loss and cost. The operating principle and steady-state analysis are discussed in detail. A prototype with 20-40-V input voltage, 200-V output voltage, and 200-W output power has been established in the laboratory. Experimental results are given to verify the analysis and advantages of the proposed converter.
219 citations
TL;DR: In this article, the authors proposed a new converter for photovoltaic (PV) water pumping or treatment systems without the use of chemical storage elements, such as batteries, to achieve a more efficient, reliable, maintenance-free, and cheaper solution than the standard ones that use dc motors or lowvoltage synchronous motors.
Abstract: This paper proposes a new converter for photovoltaic (PV) water pumping or treatment systems without the use of chemical storage elements, such as batteries. The converter is designed to drive a three-phase induction motor directly from PV energy. The use of a three-phase induction motor presents a better solution to the commercial dc motor water pumping system. The development is oriented to achieve a more efficient, reliable, maintenance-free, and cheaper solution than the standard ones that use dc motors or low-voltage synchronous motors. The developed system is based on a current-fed multiresonant converter also known as resonant two-inductor boost converter (TIBC) and a full-bridge three-phase voltage source inverter (VSI). The classic topology of the TIBC has features like high voltage gain and low input current ripple. In this paper, it is further improved with the use of a nonisolated recovery snubber along with a hysteresis controller and the use of a constant duty cycle control to improve its efficiency. Experimental results show a peak efficiency of 91% at a rated power of 210 W for the dc/dc converter plus the three-phase VSI and a peak efficiency of 93.64% just for the dc/dc converter. The system is expected to have a high lifetime due to the inexistence of electrolytic capacitors, and the total cost of the converter is below 0.43 U$/Wp. As a result, the system is a promising solution to be used in isolated locations and to deliver water to poor communities.
178 citations
TL;DR: This paper presents a power factor corrected (PFC) bridgeless (BL) buck-boost converter-fed brushless direct current (BLDC) motor drive as a cost-effective solution for low-power applications.
Abstract: This paper presents a power factor corrected (PFC) bridgeless (BL) buck-boost converter-fed brushless direct current (BLDC) motor drive as a cost-effective solution for low-power applications. An approach of speed control of the BLDC motor by controlling the dc link voltage of the voltage source inverter (VSI) is used with a single voltage sensor. This facilitates the operation of VSI at fundamental frequency switching by using the electronic commutation of the BLDC motor which offers reduced switching losses. A BL configuration of the buck-boost converter is proposed which offers the elimination of the diode bridge rectifier, thus reducing the conduction losses associated with it. A PFC BL buck-boost converter is designed to operate in discontinuous inductor current mode (DICM) to provide an inherent PFC at ac mains. The performance of the proposed drive is evaluated over a wide range of speed control and varying supply voltages (universal ac mains at 90-265 V) with improved power quality at ac mains. The obtained power quality indices are within the acceptable limits of international power quality standards such as the IEC 61000-3-2. The performance of the proposed drive is simulated in MATLAB/Simulink environment, and the obtained results are validated experimentally on a developed prototype of the drive.
172 citations
TL;DR: The proposed multi- inputs non-isolated DC/DC converter with high-voltage transfer gain benefits from various advantages such as reduced semiconductor current stress, no limitation for switching duty cycle and wide control range of different input powers.
Abstract: A new multi-input non-isolated DC/DC converter with high-voltage transfer gain is proposed in this study. The presented converter consists of the conventional buck–boost and boost converters. All the stages except the last stage are buck–boost converters. The last stage is the conventional boost converter. The proposed multi-input high-voltage gain converter benefits from various advantages such as reduced semiconductor current stress, no limitation for switching duty cycle and wide control range of different input powers. The presented converter can even operate when one or some power input fail to provide energy to the load. The steady-state operation and dynamic modelling of the suggested converter are analysed thoroughly. Experimental results are also provided to verify the feasibility of the presented converter.
165 citations
TL;DR: In this paper, a new quadratic boost converter was proposed for high voltage and high voltage gain applications, which employed only one active switch and two LC (inductor-capacitor) filters.
Abstract: A new quadratic boost converter is presented in this study. Compared with the conventional quadratic boost converter, the proposed converter has the feature of lower buffer capacitor voltage stress. This advantage is very valuable for high voltage and high-voltage gain applications. The proposed converter also employed only one active switch and two LC (inductor-capacitor) filters. Detailed analysis for its continuous current mode operation and discontinuous current mode operation both are presented. In addition, modelling for the proposed converter is also developed in this study. A prototype circuit is built and the experimental results confirm the feasibility and performance of the high step-up converter.
155 citations
TL;DR: In this article, an innovative any cell(s) to any cell (s) active balancing converter for lithium battery stack management is presented, based on multiphase converter legs connected to each lithium battery potential.
Abstract: In this paper, an innovative any cell(s) to any cell(s) active balancing converter for lithium battery stack management is presented. Based on multiphase converter legs connected to each lithium battery potential, it is able to transfer energy from any cell(s) to any cell(s). First, a basic “natural” balancing control strategy is presented. Then, based on the perspective of a high level of integration, an interleaved topology is proposed as an evolution of the converter for the downsizing of the passive components. It is explained how the large increase in the number of components is compensated by the high level of integration obtained for the given converter topology. Simulation and experimental results are provided to demonstrate the interest of the converter for active balancing of lithium-based battery stacks.
155 citations
TL;DR: In this article, the authors proposed an extendable single-stage multi-input dc-dc/ac boost converter, which includes two bidirectional ports in the converter's central part to interface output load and battery storage and several unidirectional input ports to get powers from different input dc sources.
Abstract: This paper presents a new extendable single-stage multi-input dc-dc/ac boost converter. The proposed structure comprises of two bidirectional ports in the converter's central part to interface output load and battery storage, and several unidirectional input ports to get powers from different input dc sources. In fact, the proposed topology consists of two sets of parallel dc-dc boost converters, which are actively controlled to produce two independent output voltage components. Choosing two pure dc or two dc-biased sinusoidal values as the converter reference voltages, situations of the converter operating in two dc-dc and dc-ac modes are provided, respectively. The proposed converter utilizes minimum number of power switches and is able to step up the low-level input dc voltages into a high-level output dc or ac voltage without needing any output filter. The converter control system includes several current regulator loops for input dc sources and two voltage regulator loops for generating the desired output voltage components, resulting in autonomously charging/discharging the battery to balance the power flow. Due to the converter inherent multi-input multioutput control system, the small signal model of the converter is extracted and then the pole-placement control strategy via integral state feedback is applied for achieving the converter control laws. The validity and effectiveness of the proposed converter and its control performance are verified by simulation and experimental results.
149 citations
TL;DR: In this paper, a three-port converter with high-voltage gain for stand-alone renewable power system applications is proposed, which uses only three switches to achieve the power flow control.
Abstract: In this paper, a novel three-port converter (TPC) with high-voltage gain for stand-alone renewable power system applications is proposed. This converter uses only three switches to achieve the power flow control. Two input sources share only one inductor. Thus, the volume can be reduced. Besides, the conversion ratio of the converter is higher than other TPCs. Thus, the degree of freedom of duty cycle is large. The converter can have a higher voltage gain for both low-voltage ports with a lower turns ratio and a reasonable duty ratio. The voltage stress of switches is low; thus, conduction loss can be further improved by adopting low Rds(on) switches. Therefore, the converter can achieve a high conversion ratio and high efficiency at the same time. The operation principles, steady-state analysis, and control method of the converter are presented and discussed. A prototype of the proposed converter with a low input voltage 24 V for photovoltaic source, a battery port voltage 48 V, and an output voltage 400 V is implemented to verify the theoretical analysis. The power flow control of the converter is also built and tested with a digital signal processor.
135 citations
TL;DR: Another candidate for high-power onboard charger for electric vehicles is suggested based on a discontinuous conduction mode (DCM) power factor correction (PFC) converter with harmonic modulation technique that improves the power factor in DCM PFC operation and a two-stage dc/dc converter composed of a resonant converter and a DCM buck converter.
Abstract: This paper suggests another candidate for high-power onboard charger for electric vehicles. It is based on a discontinuous conduction mode (DCM) power factor correction (PFC) converter with harmonic modulation technique that improves the power factor in DCM PFC operation and a two-stage dc/dc converter composed of a resonant converter and a DCM buck converter. Separating the functions of the dc/dc stage into control and isolation helps to reduce the transformer by using high-frequency resonance. The feasibility of the proposed charger has been verified with a 6.6-kW prototype.
128 citations
TL;DR: The proposed converter topology possesses the low switch voltage stress characteristic, which will allow one to choose lower voltage rating MOSFETs to reduce both switching and conduction losses, and the overall efficiency is consequently improved.
Abstract: In this paper, a novel transformerless interleaved high step-down conversion ratio dc-dc converter with low switch voltage stress is proposed. In the proposed converter, two input capacitors are series-charged by the input voltage and parallel-discharged by a new two-phase interleaved buck converter for providing a much higher step-down conversion ratio without adopting an extreme short duty cycle. Based on the capacitive voltage division, the main objectives of the new voltage-divider circuit in the converter are for both storing energy in the blocking capacitors for increasing the step-down conversion ratio and reducing voltage stresses of active switches. As a result, the proposed converter topology possesses the low switch voltage stress characteristic. This will allow one to choose lower voltage rating MOSFETs to reduce both switching and conduction losses, and the overall efficiency is consequently improved. Moreover, due to the charge balance of the blocking capacitor, the converter features automatic uniform current sharing characteristic of the interleaved phases without adding extra circuitry or complex control methods. The operation principles and relevant analysis of the proposed converter are presented in this paper. Finally, a 400-V input voltage, 25-V output voltage, and 400-W output power prototype circuit is implemented in the laboratory to verify the performance.
TL;DR: In this paper, a kind of interleaved non-isolated high step-up DC/DC converter is presented, which consists of two basic Boost cells and some diode-capacitor multiplier (DCM) cells as needed.
Abstract: A kind of interleaved non-isolated high step-up DC/DC converter is presented in this study. The converter consists of two basic Boost cells and some diode-capacitor multiplier (DCM) cells as needed. Because of the DCM cells, the voltage conversion ratio is enlarged and the extreme large duty ratio can be avoided in the high step-up applications. Moreover, the voltage stress of all the power devices is greatly lower than the output voltage. As a result, lower-voltage-rated power devices can be employed, and higher efficiency can be expected. Since the two basic Boost cells are controlled by the interleaving method, which means the phase difference between the two pulse width moderlation (PWM) signals is 180° and the input current is the sums of the two inductor currents, the input current ripple is decreased and the size of the input filter could be reduced, which make it a suitable choice in the photovoltaic power generation system and hybrid electric vehicles, etc. Finally, the experimental results from a 300 W, 30-400 V laboratory prototype are presented to validate the effectiveness of the proposed converter.
TL;DR: In this paper, two approaches to multiphase non-isolated dc-dc converter design are compared through theoretical analysis of respective conversion functions, input and output filter requirements, and required input inductor size.
Abstract: The paper discusses two approaches to multiphase nonisolated dc-dc converter design. An approach based on independent phases is directly compared to an approach using coupled phases. The comparison is performed through theoretical analysis of respective conversion functions, input and output filter requirements, and required input inductor size. Three-dimensional (3-D) high-power-density computer aided design (CAD) models and full-scale 56 kW prototypes based on both approaches were designed, built, and experimentally compared. As expected, the approach with independent phases has a considerable advantage regarding the low-power conversion efficiency where the efficiency can be up to 2% higher than with the coupled approach. On the other hand, the design with coupled inductors can reach power density as high as two times that of the independent phase design (87 kW/L versus 44.2 kW/L). Therefore, the use of coupled inductors may be very beneficial for space critical applications. In case of the electric vehicle power train, both factors may be very important and the suitable approach should be chosen based on system design priorities.
TL;DR: In this article, a new LLC series resonant converter that has a narrow switching frequency variation and reduced conduction losses is proposed, where one leg of the full-bridge diode rectifier is replaced with synchronous rectifier (SR) switches.
Abstract: A new LLC series resonant converter that has a narrow switching frequency variation and reduced conduction losses is proposed in this paper. In the proposed converter, one leg of the full-bridge diode rectifier is replaced with synchronous rectifier (SR) switches. In the nominal state, the proposed converter is controlled using frequency modulation, and the SR switches are controlled using in-phase switching signals with primary side switches in order that the proposed converter can obtain a reduced conduction loss in its secondary side rectifiers. During the hold-up time which is the condition where the input voltage of the converter decreases, the SR switches are controlled using phase-shifted switching signals in order that the proposed converter can obtain a higher gain without decreasing the switching frequency. Because the proposed converter operates with a narrow switching frequency variation, a small transformer core can be selected, which results in a decreased core size and loss. Furthermore, it is possible for the proposed converter to be designed optimally in the nominal state and this results in the proposed converter exhibiting a maximized efficiency over the entire load condition. The feasibility of the proposed converter is verified with a 400-250 V input and 200 V/1.5 A output prototype.
TL;DR: In this paper, a new cascade multilevel converter is introduced named ''cascade-multi-cell'' converter, which reduces the number of switches and gate driver circuits in the proposed structure.
Abstract: Recently applications of multilevel converters have been pointed out because of some advantages include high-quality output waveform, reduced harmonic distortion and lower electromagnetic interference. However, some drawbacks such as increased number of components like switches and dc power supplies and complex pulse width modulation control method are associated with these converters. In this study, a new cascade multilevel converter is introduced named `cascade-multi-cell' converter. First, the basic constitutive of the proposed multilevel converter has been explained. Then, symmetric and asymmetric configurations are presented. The number of switches and gate driver circuits in the proposed structure are less than the conventional cascade converter. Therefore its output voltage levels will be increased. Also, the number of on-state switches is reduced in presented topology, and so the conductive losses will be reduced. The peak inverse voltage of the proposed converter is equal with the traditional cascade converter. Finally, simulation and experimental results are presented. The presented results show the validity and effectiveness of the proposed multilevel structure.
TL;DR: In this paper, a half-bridge LLC resonant converter with a boost pulse width modulation (PWM) converter is proposed for hold-up state operation, which shows the same operational characteristics as the conventional LLC resonants during nominal state, which is frequency modulation (FM) method.
Abstract: This paper presents a half-bridge LLC resonant converter having a boost pulse width modulation (PWM) converter characteristic for hold-up state operation. The proposed converter is based on a half-bridge LLC resonant converter structure and a single auxiliary switch is added at the primary side. The converter has two different operational characteristics. It shows the same operational characteristic with the conventional LLC resonant converters during nominal state, which is frequency modulation (FM) method. However, when ac line lost and the converter enters into the hold-up time state, which requires wide voltage gain changes, the control method of the proposed converter is changed to the PWM method using the auxiliary switch. Since the proposed converter compensates wide voltage gain variation with PWM method of the auxiliary switch rather than adopting the FM method of main switches, the frequency variation range for the LLC resonant converter is highly reduced in the proposed converter. Therefore, the transformer in the proposed converter can be designed at the optimal operating point and it results in decreased conduction loss of the magnetizing inductor current. Furthermore, the maximum voltage gain of the proposed converter is easily increased by extending the duty ratio of the auxiliary switch. It helps to decrease the link capacitance. To verify the effectiveness of the proposed circuit, operational principle will be explained and experimental results will be presented with following specification. 100 kHz of switching frequency, 250-400 V of input voltage range, 250 V of output voltage, and 75 W output power.
TL;DR: A bidirectional isolated full-bridge dc-dc converter with a conversion ratio around nine times, soft start-up, and soft-switching features for battery charging/discharging is proposed in this paper.
Abstract: A bidirectional isolated full-bridge dc-dc converter with a conversion ratio around nine times, soft start-up, and soft-switching features for battery charging/discharging is proposed in this paper. The converter is equipped with an active flyback and two passive capacitor-diode snubbers, which can reduce voltage and current spikes and reduce voltage and current stresses, while it can achieve near zero-voltage-switching and zero-current-switching soft-switching features. In this paper, the operational principle of the proposed converter is first described, and its analysis and design are then presented. A 1.5-kW prototype with a low-side voltage of 48 V and a high-side voltage of 360 V has been implemented, from which measured results have verified the discussed features.
TL;DR: Comparisons between the two-mode control with and without IVFF compensation have been presented and the experimental results show that the TSBB converter has an improved input transient response and high efficiency over the entire input voltage range with this proposed control scheme.
Abstract: The two-switch buck-boost (TSBB) converter is suitable for wide input voltage applications. In order to achieve high efficiency over the entire input voltage range, the TSBB converter is operated in buck mode at high input voltage and boost mode at low input voltage. Such operation is called the two-mode control scheme. The objective of this paper is to propose an input voltage feed-forward (IVFF) method to reduce the influence of the input voltage disturbance on the output voltage. The small-signal models of the TSBB converter are built, and based on which, the IVFF functions under different operating modes of the TSBB converter are derived. The IVFF function in boost mode is simplified for easy implementation. The two-mode control scheme with IVFF compensation is then proposed for the TSBB converter, which realizes automatic selections of operating modes and the corresponding IVFF functions. Besides, nearly smooth switching between buck and boost modes is also guaranteed. For exhibiting the advantages of the proposed control scheme clearly, comparisons between the two-mode control with and without IVFF compensation have been presented in this paper, including the output signal of the voltage regulator and input-to-output voltage transfer function. Finally, a 250-500-V input, 360-V output, and 6-kW-rated power prototype is fabricated to validate the effectiveness of the proposed control scheme in the laboratory, and the experimental results show that the TSBB converter has an improved input transient response and high efficiency over the entire input voltage range with this proposed control scheme.
TL;DR: In this paper, a three-phase interleaved full-bridge LLC resonant converter employing a Y-connected rectifier is proposed as the isolated ac-dc high-frequency-link power-conversion system.
Abstract: The power conversion efficiency of an isolated ac-dc converter is a dominant factor in the overall efficiency of dc distribution systems. To improve the power conversion efficiency of the dc distribution system, a three-phase interleaved full-bridge LLC resonant converter employing a Y-connected rectifier is proposed as the isolated ac-dc high-frequency-link power-conversion system. The proposed Y-connected rectifier has the capability of boosting the output voltage without increasing the transformer's turn ratio. Especially, the frequency of the rectifier's output ripple is six times higher than the switching frequency, thereby reducing the output capacitor and the secondary transformer's RMS current. However, the tolerance of the converter's resonant components in each primary stage causes the unbalance problem of output ripple current. It cannot be solved using conventional control techniques since the structure of the three-phase interleaving has the limitations of individual control capability for each converter. To solve the current unbalance problem, a current balancing method is proposed for the output rectifying current. The performance of the proposed converter and the current balancing method has been verified through experiments using a 10 kW (300 V/33.3 A) prototype converter.
TL;DR: A novel buck-boost DC/DC converter that expands the continuous conduction mode (CCM) operational region and reduces the voltage stresses across the capacitors so that the current stresses on diodes are reduced.
Abstract: In this study, a novel buck-boost DC/DC converter is presented. The circuit structure of the proposed converter consists of a single power switch, two diodes and some energy storage elements. Employing only a single power switch reduces the implementation cost and switching power losses. The proposed converter has higher voltage gain in step-up mode in comparison with conventional buck-boost and Cuk converter. In addition, this converter expands the continuous conduction mode (CCM) operational region. The presented converter has three operation modes in CCM. The second mode reduces the voltage stresses across the capacitors. Therefore the current stresses on diodes are also reduced. To verify the operation of the proposed converter, the experimental results are provided using a hardware prototype.
TL;DR: Compensation of the dc-side voltage harmonics of a medium-voltage 12-pulse ac/dc converter is achieved using a series active power filter (APF) to reduce inverter losses.
Abstract: In this paper, compensation of the dc-side voltage harmonics of a medium-voltage (MV) 12-pulse ac/dc converter is achieved using a series active power filter (APF). The output voltage harmonics are dependent on the converter firing delay angles and, consequently, on the specific power locus followed by the ac/dc converter. This power locus ensures minimum fifth and seventh harmonics (total rms) in the input current which provides minimum input current total harmonic distortion when the reactive power is less than 0.5 p.u. The series APF is connected between the load and the converter output via a magnetic amplifier to eliminate the dc current from the APF inverter, thus reducing inverter losses. Voltage harmonic compensation using a series APF, with and without a magnetic amplifier, is examined with both resistive and inductive loads. The simulation results for compensating a 3.3-kV MV 12-pulse converter system are experimentally verified using a scaled prototype 12-pulse converter with a series APF.
01 Jan 2014
TL;DR: In this article, the implementation of Perturb and Observe MPPT using buck and buck-boost Converters has been discussed and some results such as current, voltage and output power for each various combination have been recorded.
Abstract: The Maximum Power Point Tracking (MPPT) is a technique used in power electronic circuits to extract maximum energy from the Photovoltaic (PV) Systems. In the recent decades, photovoltaic power generation has become more important due its many benefits such as needs a few maintenance and environmental advantages and fuel free. However, there are two major barriers for the use of PV systems, low energy conversion efficiency and high initial cost. To improve the energy efficiency, it is important towork PV system always at its maximum power point. So far,many researches are conducted and many papers were published and suggested different methods for extracting maximum power point. This paper pre sents in details implementation of Perturb and Observe MPPT using buck and buck -boost Converters. Some results such as current, voltage and output power for each various combination have been recorded. The simulation has beenaccomplishedin software of MATLAB Math works.
TL;DR: This paper presents a novel active buck-boost inverter (ABI) topology suitable for wide-range input, which can realize buck- boost conversion in a quasi-single-stage inverter.
Abstract: The voltage range of a renewable energy source, such as the photovoltaic cell, is influenced by the environment, light, temperature, and so on. The power conditioning system should adapt to the wide input voltage and have buck-boost ability. Based on the structure of the “ac/ac unit,” this paper presents a novel active buck-boost inverter (ABI) topology suitable for wide-range input, which can realize buck-boost conversion in a quasi-single-stage inverter. The ac/ac unit composed of active switches is utilized to perform voltage boost without introducing additional passive elements, which is in favor to the system power density and efficiency. Operational analysis in buck and boost modes are presented, and the modulation strategy applied in the ABI is also developed. Simulation and experimental results are presented to verify the operational principle and its modulation strategy.
TL;DR: A novel buck–boost converter is presented in this study that inherits all the advantages of Cuk converter such as low output voltage ripple and minimal radio frequency interference and some implementation problems of KY converters are solved.
Abstract: A novel buck–boost converter is presented in this study. This converter is based on Cuk converter. Therefore it inherits all the advantages of Cuk converter such as low output voltage ripple and minimal radio frequency interference. In addition, some implementation problems of KY converters are solved. The proposed converter has higher voltage gain in step-up mode in comparison with Cuk converter. Moreover, this converter expands the continuous conduction mode (CCM) operational region. In the suggested topology, the gate of the switch is referenced to ground, so this converter does not need a floating gate drive. Simulation results of the suggested converter are presented in different operational conditions. To verify the operation of the proposed converter, experimental results are provided using a hardware prototype that operates in both CCM and discontinuous conduction mode.
TL;DR: In this article, the authors proposed a novel isolated hybrid resonant converter with smooth transition between multiple operating modes. But, the converter's topology and operating modes are not discussed, and closed-loop input-voltage controllers are designed for the different operating modes, and a smooth transition technique is introduced using a two-carrier modulation scheme.
Abstract: This paper introduces a novel isolated hybrid resonant converter with smooth transition between multiple operating modes. With the simple addition of a bidirectional ac switch, the highly efficient series resonant converter operating in the discontinuous conduction mode is combined with a phase-shifted full-bridge buck converter and a pulsewidth-modulated boost converter in order to provide high power conversion efficiency over a wide input-voltage operating range utilizing a simple topology and simple control techniques. First, the topology is introduced, and the converter's operating modes are discussed. Next, closed-loop input-voltage controllers are designed for the different operating modes, and a smooth transition technique is introduced using a two-carrier modulation scheme. Experimental results are provided to verify the proposed system using a 300-W prototype that achieved a 97.5% California Energy Commission weighted efficiency with a 30-V input including all auxiliary and control losses.
TL;DR: The small signal and dynamic characteristics analyses show that the proposed converter has the same static and dynamic responses as the CBC, and the input current ripple cancellation can be achieved in all power ranges without significantly increasing the losses.
Abstract: This paper presents a boost converter with a proposed tapped inductor ripple cancellation network. Based on the conventional boost converter (CBC), a small capacitor and a small inductor are added as the ripple cancellation network (RCN) in the proposed converter. Meanwhile, the tapped inductor can be easily realized by adding an extra tap in the main inductor of the CBC. Since the capacitor and inductor in the RCN do not need to handle the main power as the conventional LC input filter, the size and weight of the proposed converter are relatively small comparing the CBC with the LC input filter. The small signal and dynamic characteristics analyses show that the proposed converter has the same static and dynamic responses as the CBC, and the input current ripple cancellation can be achieved in all power ranges without significantly increasing the losses. Finally, three 36-50-V, 500-W prototypes operating at 100 kHz are implemented to verify the expected performance. The simulation and experimental results show that the proposed converters can achieve input current ripple cancellation with efficiency higher than 97.4% in all power ranges.
TL;DR: In this paper, a new boost converter with an active snubber cell is proposed, which provides main switch to turn ON with zerovoltage transition (ZVT) and to turn OFF with zero-current transition(ZCT).
Abstract: In this study, a new boost converter with an active snubber cell is proposed. The active snubber cell provides main switch to turn ON with zero-voltage transition (ZVT) and to turn OFF with zero-current transition (ZCT). The proposed converter incorporating this snubber cell can operate with soft switching at high frequencies. Also, in this converter all semiconductor devices operate with soft switching. There is no additional voltage stress across the main and auxiliary components. The converter has a simple structure, minimum number of components, and ease of control as well. The operation principle and detailed steady-state analysis of the novel ZVT-ZCT-PWM boost converter are given. The presented theoretical analysis is verified exactly by a prototype of 100 kHz and 1 kW converter. Also, the overall efficiency of the new converter has reached a value of 97.8% at nominal output power.
01 Dec 2014
TL;DR: In this article, a buck-boost converter is employed to drive a brushless DC motor driven water pump to achieve the maximum efficiency of the solar PV array and the soft starting of the permanent magnet brushless dc motor by proper control.
Abstract: Solar photovoltaic (SPV) array based water pumping is receiving wide attention now a days because the everlasting solar energy is the best alternative to the conventional energy sources. This paper deals with the utilization of a buck-boost converter in solar PV array based water pumping as an intermediate DC-DC converter between a solar PV array and a voltage source inverter (VSI) in order to achieve the maximum efficiency of the solar PV array and the soft starting of the permanent magnet brushless DC (BLDC) motor by proper control. Consisting of a least number of components and single switch, the buck-boost converter exhibits very good conversion efficiency. Moreover, buck-boost DC-DC converter topology is the only one allowing follow-up of the PV array maximum power point (MPP) regardless of temperature, irradiance, and connected load. A BLDC motor is employed to drive a centrifugal type of water pump because its load characteristic is well matched to the maximum power locus of the PV generator. The transient, dynamic and steady state behaviors of the proposed solar PV array powered buck-boost converter fed BLDC motor driven water pumping system are evaluated under the rapid and slowly varying atmospheric conditions using the sim-power-system toolboxes of the MATLAB/Simulink environment.
TL;DR: In this article, a high step-up converter combining one coupling inductor and two bootstrap capacitors, together with the active voltage-clamping circuit which pumps portion of the leakage inductance energy to the output, is presented.
Abstract: As generally acknowledged, the high step-up dc-dc converter is widely used in the sustainable energy system as the front-end stage of the dc-ac converter. Therefore, a high step-up converter combining one coupling inductor and two bootstrap capacitors, together with the active voltage-clamping circuit which pumps portion of the leakage inductance energy to the output, is presented herein. By doing so, the efficiency at light load can be upgraded greatly, and hence tends to be flat between the minimum load and the rated load. In this letter, the basic operating principles of this converter are first illustrated in detail, and second some experimental results are provided to demonstrate the effectiveness of the proposed high step-up converter topology.
TL;DR: In this paper, a single-phase high step-up converter is proposed, which not only boosts the relatively low photovoltaic voltage to a high bus voltage with high efficiency, but also offers a neutral point terminal for the half-bridge-based inverters.
Abstract: In this paper, a single-phase high step-up converter is proposed, designed not only to boost the relatively low photovoltaic (PV) voltage to a high bus voltage with high efficiency, but also to offer a neutral point terminal for the half-bridge-based inverters. First and foremost, two symmetrical high step-up converters are combined and integrated to derive an improved converter with neutral point terminal, which is strongly expected for the half-bridge-based inverters. Secondly, the voltage gain of the converter is extended and the narrow turn-off period is avoided by using the coupled inductor multiplier. Furthermore, the coupled inductor multiplier reduces the voltage stress of all the power devices. As a result, the low voltage-rated power devices can be employed to minimize the conduction losses. More importantly, all the active switches work in the zero-voltage-switching condition, which reduces the switching losses effectively. All these factors improve the circuit performance in the high step-up applications, especially for the half-bridge based PV inverter systems. Finally, the experimental results from a 500 W, 48 -760 V prototype at 100 kHz switching frequency are provided to verify the effectiveness of the proposed converter. The highest efficiency of the prototype is 96.5% and the efficiency is over 94% in a wide load range.