Showing papers on "Buck–boost converter published in 2019"
TL;DR: A dynamic modeling and control of PV/Wind/Wave energy hybrid system and the effectiveness of the simulated model is found to be practical, and the model is proven to be used in the integration of the three proposed energies.
101 citations
TL;DR: A new transformer-less buck-boost converter, which owns a quadratic voltage gain ratio and the count of power switches, is proposed, which works both in step-up or step-down mode, while most of the existing Quadratic topologies are able to work either in step up or step down mode.
Abstract: A new transformer-less buck-boost converter is proposed, which owns a quadratic voltage gain ratio. The proposed converter (a) has only one active switch, which makes the implementation of the gate driver and control system simpler; (b) has a quadratic voltage gain without using a transformer, which equips the designers to obtain a high-voltage gain ratio and avoid the complexity of magnetic utilisations; (c) works both in step-up or step-down mode, while most of the existing quadratic topologies are able to work either in step-up or step-down mode; and (d) shares a common ground between the input and output terminals. The operating states of the proposed converter along with its steady-state performance are analysed. Then, the small-signal modelling and the power loss analysis are performed. A comparison shows the unique features of the converter, specifically in terms of voltage gain ratio and the count of power switches. Finally, the experimental results of a laboratory prototype, as well as the simulation results from PSIM software, are used for validation. The converter was tested in different conditions to inspect its transient response and to record its efficiency. The maximum recorded efficiencies in boost and buck modes, respectively were 94.7 and 93%.
69 citations
TL;DR: This paper introduces a high-efficiency and high-density single-phase dual-mode cascaded buck–boost multilevel transformerless photovoltaic (PV) inverter for residential application that combines a regulated cascaded H-bridge multileVEL inverter stage with an unregulated GaN-based ac boost converter.
Abstract: This paper introduces a high-efficiency and high-density single-phase dual-mode cascaded buck–boost multilevel transformerless photovoltaic (PV) inverter for residential application. This inverter topology combines a regulated cascaded H-bridge multilevel inverter stage with an unregulated GaN-based ac boost converter. The cascaded H-bridge inverter and the ac boost share a common inductor. Compared with the traditional cascaded H-bridge PV inverter, this topology significantly enlarges the input voltage range due to the additional ac boost. And, a flexible number of PV panels can be used. To control the multiple dc-link PV voltages and to reduce the switching loss of the ac boost, this paper further introduces a dual-mode operation. The two modes are buck mode and buck–boost mode. To maximize the utilizations of the dc-link voltages, this paper presents a minimized ac boost duty-cycle generation strategy with feedforward. Then, a dual-mode modulation based on the boost feedforward duty-cycle generation is introduced. This paper also uses an indirect current control for this inverter, since the ac boost is an unregulated stage. The ac boost stage is implemented with two interleaved phases and the ac switches based on the 650-V E-mode GaN FETs. Finally, an 8-port 2-kW prototype based on this topology is developed and demonstrated. Compared with the state-of-the-art microinverter-based 2-kW PV inverter system, the developed inverter prototype achieves 40% reduction of the total power loss, 25% improvement of the power density, 37.5% reduction of the power connectors, 50% reduction of the device count, and 87.5% reduction of the main magnetic count. Operating with natural convection cooling, this PV inverter achieves 98.0% efficiency at 60% of load and 97.8% efficiency at full load. The power density of the packaged PV inverter is 5.8 W/in3.
63 citations
TL;DR: In this paper, the authors proposed a new bidirectional buck-boost converter, which is a key component in a photovoltaic and energy storage system (ESS) to reduce the output current ripple by providing a current path.
Abstract: This paper proposes a new bidirectional buck–boost converter, which is a key component in a photovoltaic and energy storage system (ESS) Conventional bidirectional buck–boost converters for ESSs operate in discontinuous conduction mode (DCM) to achieve zero-voltage switching turn- on for switches However, operation in DCM causes high ripples in the output voltage and current, as well as low power-conversion efficiency To improve the performance of the conventional converter, the proposed converter has a new combined structure of a cascaded buck–boost converter and an auxiliary capacitor The combined structure of the proposed converter reduces the output current ripple by providing a current path and the efficiency is increased A prototype was built and tested to verify the effectiveness of the converter The proposed converter has a maximum efficiency of 98%, less than ${\text{514}}{\ \text{V}}_{{\text{pp}}}$ of output voltage ripple, and less than ${\text{712}}{\ \text{A}}_{{\text{pp}}}$ of output current ripple These results were obtained at an input voltage of 160 V, switching frequency of 45 kHz, output voltage of 80–320 V, and output power of 16–160 W The experimental results show that the proposed converter has improved performance compared to the conventional converter
55 citations
TL;DR: An equalization algorithm, which compensates the battery internal resistance induced state-of-charge error, is proposed to improve the equalization accuracy and demonstrate obvious efficiency enhancement over the conventional method.
Abstract: Compared with the conventional hard switching battery equalizers, hierarchical battery equalizer based on the bipolar continuous-conduction mode buck–boost units could effectively reduce the switching loss and improve the conversion efficiency. This paper mainly addresses the key technical challenges associated with the optimal design of this battery equalizer. The inductor current is controlled to enter into the negative region. Thus, the mosfet body diode provides a freewheeling path for the inductor current during the dead band. This ensures zero-voltage switching turn- on of both power mosfet s in each buck–boost unit without auxiliary snubbers. Therefore, the switching losses are significantly reduced. Meanwhile, the integral of the inductor negative current is precisely controlled to minimize the circulating current. This guarantees both minimized conduction losses and suitable equalization speed. Furthermore, an equalization algorithm, which compensates the battery internal resistance induced state-of-charge error, is proposed to improve the equalization accuracy. The operating principles and design considerations are analyzed in detail. An experimental prototype to balance four series-connected lithium-ion battery cells is implemented. The experimental results validate the design of the equalizer and demonstrate obvious efficiency enhancement over the conventional method.
54 citations
01 Dec 2019
TL;DR: In this article, a two-third pulse-width modulation (2/3-PWM) scheme is proposed to shape the DC-link current with the input stage, and the desired 3-Φ sinusoidal load phase currents are generated by switching only two out of the three phases of the output stage.
Abstract: Latest dual-gate (2G) monolithic bidirectional (MB) gallium nitride (GaN) enhancement-mode field effect transistors (e-FETs) enable a performance breakthrough of current DC-link inverters, e.g., in terms of power conversion efficiency, power density, cost and complexity. In fact, a single 2G MB GaN e-FET can replace the two anti-series connected conventional power semiconductors required in this inverter topology, realizing a four-quadrant (AC) switch with bidirectional voltage blocking capability and allowing controlled bidirectional current flow. Furthermore, as shown in this paper in case of three-phase (3-Φ) buck-boost (bB) current source inverter (CSI) systems comprising a DC-link current impressing buck-type DC/DC input stage and a subsequent boost-type 3-Φ current DC-link inverter output stage, a variable DC-link current control strategy, based on a Synergetic Control concept, can be applied to significantly reduce the switching losses occurring in the 3-Φ inverter. This strategy is denominated two-third pulse-width modulation (2/3-PWM), since by properly shaping the DC-link current with the input stage, the desired 3-Φ sinusoidal load phase currents can be generated by switching, in each switching period, only two out of the three phases of the output stage. Based on comprehensive circuit simulations and analytical calculations, a detailed explanation of the developed modulation and control schemes in different operating conditions is provided, and the reduction of losses enabled by 2/3-PWM is confirmed. Next, the seamless transition of the 3-Φ bB CSI system from 2/3-PWM to conventional 3/3-PWM is demonstrated. Finally, a 3.3 kW 3-Φ bB CSI system, applying 2/3-PWM and employing research samples of 2G MB GaN e-FETs in the 3-Φ inverter, is estimated to achieve an efficiency of 98.4% and a power density of 18 kW/dm(295 W/in) at a switching frequency of 140 kHz.
52 citations
TL;DR: By using a switch fault management unit with reduced complexity, inserted between the control block and the switches, an unified, efficient, and optimized fault-tolerant control, suitable in both healthy and postfault operations is designed.
Abstract: In photovoltaic systems, dc–dc converters have been identified as one of the most critical and challenging subsystem in terms of failure rate. Thus, this paper proposes fault-tolerant operation of a two-stage buck/buck–boost converter under open-circuit switch failure. Remedial actions are efficient in any failure of one of the two switches of the converter. Here, a new unified approach is considered, for the overall fault-tolerant operation of the two stages of the converter. The fault-tolerant circuit we propose lies on performing redundancy by implementing the equivalent synchronous switch for the two main switches of the two stages, in offline mode. The fault-tolerant circuit results from the basic two-stage buck/buck-boost converter and its equivalent circuit with a synchronous switch, merged together to form the new dc–dc fault-tolerant circuit. Therefore, postfault operation at full power can also be performed. By using a switch fault management unit with reduced complexity, inserted between the control block and the switches, we have designed an unified, efficient, and optimized fault-tolerant control, suitable in both healthy and postfault operations. Some selected experimental tests, which all confirm the good performances of the proposed fault-tolerant approach, are presented and discussed.
51 citations
TL;DR: This paper proposes a novel single-stage buck-boost three-Level neutral-point-clamped (NPC) inverter with two independent dc sources coupled for the grid-tied photovoltaic application, which can effectively solve the unbalanced operational conditions generally appearing between two independent PV sources.
Abstract: This paper proposes a novel single-stage buck-boost three-Level neutral-point-clamped (NPC) inverter with two independent dc sources coupled for the grid-tied photovoltaic (PV) application, which can effectively solve the unbalanced operational conditions generally appearing between two independent PV sources. The proposed control scheme can simultaneously guarantee the maximum power point (MPP) operation of both PV sources and maintain the output waveform quality. Compared to the traditional two-stage PV inverter, the proposed NPC inverter could reduce the PV array voltage requirement and the voltage rating of dc-link capacitors; also it shows advantages in operational efficiency. MATLAB simulations and experimental results are presented to examine the performance of the proposed three-level NPC inverter.
45 citations
TL;DR: The operational principle, steady-state analysis, and small-signal modeling of the proposed buck–boost converter in continuous conduction mode are presented, and it is found that the proposed converter's voltage gain is smaller than the other converters’ in step-down mode.
Abstract: In this paper, a novel buck–boost converter with low electric stress on components and negative output voltage is proposed. The operational principle, steady-state analysis, and small-signal modeling of the proposed buck–boost converter in continuous conduction mode are presented. Comparisons among another five buck–boost converters and the proposed buck–boost converter are presented. It is found that the proposed converter's voltage gain is smaller than the other converters’ in step-down mode. Also, based upon the comparisons among the same kind and same number of components, the voltage and current stresses on the power switch of the proposed buck–boost converter are less than or equal to those of the comparative converters, and the voltage stress on the charge pump capacitor and the switching device power rating of the proposed buck–boost converter are always lower than those of other comparative converters. The efficiency of the proposed buck–boost converter is highest among those converters having the same number of elements. These advantages make component selection for the proposed converter much easier, and it can be used directly in applications needing a negative voltage source. Finally, simulation results and circuit experiments are given for validating the effectiveness of the proposed buck–boost converter.
43 citations
TL;DR: The proposed transformerless buck-boost DC-DC converter with positive output voltage benefits from continuous input current, which makes it more suitable for renewable energy applications and compared to other quadratic buck- boost topologies in terms of different criteria.
41 citations
TL;DR: A constant frequency zero-voltage-switching (ZVS) control strategy with a minimum root mean square (rms) value of inductor current is proposed in this letter for the four-switch buck–boost (FSBB) dc–dc converter that is used as a 48 V intermediate bus pre-regulator in distributed power systems.
Abstract: A constant frequency zero-voltage-switching (ZVS) control strategy with a minimum root mean square (rms) value of inductor current is proposed in this letter for the four-switch buck–boost (FSBB) dc–dc converter that is used as a 48 V intermediate bus pre-regulator in distributed power systems. The quadrilateral inductor current modulation is adopted to achieve ZVS operation. The four control time intervals are optimally selected such that the inductor current rms value is minimized, thus reducing the conduction loss. The proposed closed-loop ZVS control scheme can be implemented without sensing the load current, although the rms minimum current algorithm needs the input and output voltages and load current at given a steady-state condition. The control scheme is verified in a 300 W dc–dc prototype of the ZVS FSBB converter. The input voltage and load transition tests are provided to verify the closed-loop characteristics without sensing load current.
TL;DR: This paper describes a novel family of single-phase single-stage buck–boost inverters using output unfolding circuits usingoutput unfolding circuits based on operation principles and component design guidelines along with modulation techniques.
Abstract: This paper describes a novel family of single-phase single-stage buck–boost inverters using output unfolding circuits. Operation principles and component design guidelines along with modulation techniques are presented and discussed. The simulation results confirm all theoretical statements. Experimental setup of the most promising solution is assembled and tested, where the efficiency for different operation modes is analyzed. Finally, the pros and cons along with applications of the proposed solutions are discussed in the conclusions.
TL;DR: The proposed BMPG has hardware features that allow modularity, redundancy, and scalability as well as operational features that alleviate the need of series-connected switches and allows generation of a wide range of pulse waveforms.
Abstract: In order to overcome the limitations of the existing classical and solid-state Marx pulse generators, this paper proposes a new modular multilevel voltage-boosting Marx pulse generator (BMPG). The proposed BMPG has hardware features that allow modularity, redundancy, and scalability as well as operational features that alleviate the need of series-connected switches and allows generation of a wide range of pulse waveforms. In the BMPG, a controllable, low-voltage input boost converter supplies, via directing/blocking (D/B) diodes, two arms of a series modular multilevel converter half-bridge sub-modules (HB-SMs). At start up, all the arm's SM capacitors are resonantly charged in parallel from 0 V, simultaneously via directing diodes, to a voltage in excess of the source voltage. After the first pulse delivery, the energy of the SM capacitors decreases due to the generated pulse. Then, for continuous operation without fully discharging the SM capacitors or having a large voltage droop as in the available Marx generators, the SM capacitors are continuously recharged in parallel, to the desired boosted voltage level. Because all SMs are parallelly connected, the boost converter duty ratio is controlled by a single voltage measurement at the output terminals of the boost converter. Due to the proposed SMs structure and the utilization of D/B diodes, each SM capacitor is effectively controlled individually without requiring a voltage sensor across each SM capacitor. Generation of the commonly used pulse waveforms in electroporation applications is possible, while assuring balanced capacitors, hence SM voltages. The proposed BMPG has several topological variations such as utilizing a buck–boost converter at the input stage and replacing the HB-SM with full-bridge SMs. The proposed BMPG topology is assessed by simulation and scaled-down proof-of-concept experimentation to explore its viability for electroporation applications.
TL;DR: An adaptive switching frequency modulation that optimizes the efficiency of the cascaded buck-boost (CBB) converter and a small volume low-profile planar-nanocrystalline inductor is designed to further increase efficiency and power density.
Abstract: This paper first presents an adaptive switching frequency modulation that optimizes the efficiency of the cascaded buck-boost (CBB) converter. Such bidirectional dc–dc CBB topology is typically deployed in PV-battery-device systems. A precise loss-model that accounts for component nonlinearities is developed to determine power-loss distribution. According to the loss model, optimal switching frequencies are selected that correspond to the lowest total loss in both the buck and the boost modes of the operation. Then, a small volume low-profile planar-nanocrystalline inductor is designed to further increase efficiency and power density. Finite element analysis method is used to evaluate the inductor design. A digital control system is designed to periodically adjust the optimal switching frequencies to modulate the pulsewidth modulation duty cycle and to take into account any load and line regulations. The objective of this paper is to achieve ultra-high efficiency (over 99%) for a well-known CBB converter. A 100 W CBB converter prototype was built to verify the proposed algorithm and designed nanocrystalline inductor. A California Energy Commission weighted efficiency of 98.87% with a peak efficiency of 99.31% was achieved for the buck mode and 98.58% with a peak efficiency of 99.25% was achieved for the boost mode, both at nominal voltage. Also, a power density of 3.67 kW/L was reported.
03 Jun 2019
TL;DR: In this article, the authors proposed a two-third modulation strategy for a buck-boost (bB) current source inverter to achieve the desired 3-Φ sinusoidal load currents by switching only two out of the three phases of the output stage.
Abstract: The unprecedented characteristics of dual-gate (2G) monolithic bidirectional (MB) gallium nitride (GaN) enhancement-mode field-effect transistors (e-FETs) enable a potential performance breakthrough of current DC-link inverters, e.g. in terms of power conversion efficiency, power density, cost and complexity. In fact, a single 2G MB GaN e-FET can conveniently replace and outperform two anti-series connected conventional power semiconductors to realize the four-quadrant (AC) switch required in this circuit topology. Furthermore, a variable DC-link current control strategy can be applied to a three-phase (3-Φ) buck-boost (bB) current source inverter (CSI) system comprising a DC-link current impressing buck-type DC/DC input stage and a subsequent boost-type 3-Φ current DC-link inverter output stage to significantly reduce the occurring losses. The proposed strategy is denominated Two-Third Modulation, since by properly shaping the DC-link current with the input stage by means of a Synergetic Control structure, it allows to generate the desired 3-Φ sinusoidal load currents by switching only two out of the three phases of the output stage. Circuit simulations of the 3-Φ bB CSI system support the explanation of the analyzed concept and confirm the associated reduction of losses, for which analytical expressions are as well derived. Finally, the operation of new 2G MB GaN e-FET research samples is verified in a hardware prototype, taking the first step towards the practical realization of the described power converter.
TL;DR: In this article, an adaptive interconnection and damping assignment passivity based control that incorporates the immersion and invariance parameter estimator for the load power is proposed to solve the problem of regulating the output voltage of a DC-DC buck-boost converter feeding a constant power load.
Abstract: This paper addresses the problem of regulating the output voltage of a DC-DC buck-boost converter feeding a constant power load,which is a problem of current practical interest. Designing a stabilising controller is theoretically challenging because its average model is a bilinear second order system that, due to the presence of the constant power load,is non- minimum phase with respect to both states.Moreover,to design a high performance controller, the knowledge of the extracted load power, which is difficult to measure in industrial applications, is required. In this paper, an adaptive interconnection and damping assignment passivity based control that incorporates the immersion and invariance parameter estimator for the load power is proposed to solve the problem. Some detailed simulations are provided to validate the transient behaviour of the proposed controller and compare it with the performance of a classical PD scheme.
TL;DR: In this paper, a peak current mode (PCM) memristive buck-boost converter with a voltage-controlled load emulator was investigated and the effect of the load on the buckboost converter was uncovered.
Abstract: When an output load of switching DC-DC converter exhibits the fingerprints of frequency dependent pinched hysteresis loops, the load can be regarded as a memristive load. By substituting a resistive load with the voltage-controlled memristive load emulator, a peak current mode (PCM) memristive buck-boost converter is presented in this paper. Based on the circuit equations under two kinds of switch states, the switched conditions and normalized system model of the PCM memristive buck-boost converter operating at continuous conduction mode (CCM) are derived. Through MATLAB numerical plots, dynamical behaviors of the PCM memristive buck-boost converter are investigated and dynamical effects of the memristive load on the buck-boost converter are thereby uncovered. The results indicate that such a buck-boost converter exhibits complex dynamical behaviors including chaos, period, period-doubling bifurcation, and border collision bifurcation; the memristive load does not affect the bifurcation structures but can make the normal operation region to broaden and cause the average output voltages to drop. Additionally, the enlargement of the memristive effect of the load, the normal operation regions are further expanded and the average output voltages are further reduced. Finally, PSIM simulation model is constructed, upon which circuit simulations effectively confirm the numerical plots.
TL;DR: The proposed converter is capable of operating in stand-alone buck or boost mode in addition to its primary operation of performing the buck–boost conversion and its effectiveness is demonstrated in terms of reduced source current ripple along with seamless transition from buck to boost mode and vice versa.
Abstract: A switching-capacitor-based buck–boost converter (with common ground) for point of load applications is proposed in this paper. It is capable of operating in stand-alone buck or boost mode in addition to its primary operation of performing the buck–boost conversion. The striking feature of the proposed converter is low source current ripple content irrespective of its mode of operation (buck–boost, buck, or boost). First, feasible pulsewidth modulation schemes for the proposed converter are identified and thereafter the corresponding circuit performance analysis, steady-state analysis, and state-space modelling is established. Through steady-state analysis, voltage gain expressions are formulated and equations defining L - C components are derived in terms of their ripple quantities. The state-space models are used to formulate small-signal analysis and to obtain the relevant transfer functions required in the controller design. A voltage-mode/current-mode controller is designed, with a tradeoff in bandwidth, to control the proposed converter and transit it from buck to boost mode or vice versa seamlessly. A 30–55 W , 100 kHz, prototype point of load converter with 36-V input dc source is built to supply power at constant load voltage of either 48 or 28 V. The proposed converters’ effectiveness is demonstrated experimentally in terms of reduced source current ripple along with seamless transition from buck to boost mode and vice versa.
TL;DR: The Lyapunov theory-based analysis has been incorporated, which gives asymptotic stability of the entire system to track the reference signals, and the comparison of the same HEV system of the proposed nonlinear technique has been included in this paper using MATLAB/Simulink.
Abstract: Depletion of hydrocarbons and increasing environmental pollution is pushing the researchers to work on finding some alternatives. Going for pure or hybrid electric vehicles (HEVs) seems a good option as it offers limitless energy option, which is environmentally friendly as well. In this paper, the contribution fuel cell is used as a primary/main source and an ultra-capacitor has been used as an auxiliary one, both connected to a dc bus through the dc–dc buck boost converter. This system harnesses energy from the sources as per the vehicle’s demand. The supply of energy from both the sources has been controlled by the switches, for which integral backstepping-based nonlinear controller has been proposed. The Lyapunov theory-based analysis has been incorporated, which gives asymptotic stability of the entire system to track the reference signals. The comparison of the same HEV system of the proposed nonlinear technique has also been included in this paper using MATLAB/Simulink.
TL;DR: This paper presents an efficiency-enhanced low-profile zero-voltage-transition (ZVT) synchronous non-inverting buck-boost converter for 48-V tens-of-Watt output applications that reduces the required number of auxiliary components, thereby decreasing the converter volume and power loss.
Abstract: This paper presents an efficiency-enhanced low-profile zero-voltage-transition (ZVT) synchronous non-inverting buck-boost converter for 48-V tens-of-Watt output applications. By only using three auxiliary components shared between two switching nodes, zero-voltage switching (ZVS) of all four power switches and zero-current switching of the auxiliary switch are achieved in the proposed converter to minimize the switching power loss. Compared with the existing ZVT topologies, the proposed converter reduces the required number of auxiliary components, thereby decreasing the converter volume and power loss. In addition, the proposed converter can be configured into the buck mode with full ZVS capability to support a wide input range from 36 V to 90 V. Experimental results show that the proposed converter can operate at 1 MHz and deliver a maximum output power of 75 W. The measured peak power efficiencies achieve 92.5% and 96.3% in the buck-boost mode and buck mode, respectively. Compared with the state-of-the-art ZVS-based buck-boost counterpart, the proposed converter reduces the volume of the auxiliary circuit by ~2 times even with 28% increase in the maximum load current and two times reduction in the switching frequency, and provides higher peak power efficiencies in both buck-boost and buck modes.
TL;DR: A comprehensive comparison and analysis of the differences between NIBB and conventional buck boost converters was conducted in terms of their operation principles, which includes multi-mode control strategy and dual-edge modulation here, and also the characteristics of switches and passive components in the two converters were analysed.
Abstract: The non-inverting buck boost (NIBB) converter has attracted significant attention in recent years, as it shares ground between input and output, and the voltage stress of switches is lower. In order to investigate the differences between NIBB and conventional buck boost converters, a comprehensive comparison and analysis of these two converters were conducted in terms of their operation principles, which includes multi-mode control strategy and dual-edge modulation here, and also the characteristics of switches and passive components in the two converters were analysed. The results show that NIBB is better than conventional buck boost circuit in these aspects of electrical stress, power loss, cost, passive component volume, and so on. Two prototypes for the two converters with 10 kW/20 kHz were designed and simulated, respectively, for verifying the results. Analytical and simulated results confirmed the conclusions.
TL;DR: The proposed reversely polarized energy recycling (RPER) technique improves not only the conversion efficiency at low input voltage but also the system’s output power range from the proposed RPER technique.
Abstract: This paper presents a single-inductor triple-source quad-mode (SITSQM) energy-harvesting interface in a 0.18- $\mu \text{m}$ CMOS process. The proposed reversely polarized energy recycling (RPER) technique improves not only the conversion efficiency at low input voltage but also the system’s output power range. The interface employs the buck–boost topology to convert energy from photovoltaic (PV) cells and a thermoelectric generator (TEG) to a regulated 1.2-V output. The proposed converter features four different operating modes, namely, harvesting, recycling, storing, and backup. The operating mode is automatically selected according to the input and load conditions using the automatic source selection mechanism. The experimental results demonstrate 25.3% efficiency improvement and 10 $\times $ output power range extension from the proposed RPER technique. The proposed SITSQM converter automatically manages three harvesting sources with 82.1% peak conversion efficiency.
TL;DR: A three-phase buck–boost derived PFC converter with three switches and with input inductors connected in delta configuration for use in MEA is presented, operated in a discontinuous conduction mode to achieve PFC at ac input.
Abstract: In more electric aircraft (MEA), three-phase power factor correction (PFC) rectifiers of several kilowatts are required. In this paper, a three-phase buck–boost derived PFC converter with three switches and with input inductors connected in delta configuration for use in MEA is presented. The proposed converter is operated in a discontinuous conduction mode to achieve PFC at ac input. This avoids the inner current control loop which further eliminates the current sensors. It requires only one output voltage sensor unlike five sensors in conventional PFC converter for its control implementation. This makes the system cost effective, more reliable, and robust. A simple voltage control loop is used to generate the gate signals. The steady state operation of the converter and detailed design calculations are presented. For each power component, the analytical expressions for calculating the average and rms current ratings are derived to facilitate the converter design. The small-signal model of the converter is presented to aid the controller design. The experimental results from a 2 kW laboratory prototype are presented to confirm the operation of the proposed converter. An input power factor of 0.999, an input current total harmonic distortion of as low as 2.76%, and a high conversion efficiency of 96% are achieved from the prototype.
TL;DR: The single-stage light-emitting diode driver based on interleaving buck–boost circuit and CLCL resonant circuit achieved an effective integration as well as kept their respective working conditions through the switch integration and the system efficiency was high.
Abstract: A single-stage light-emitting diode driver based on interleaving buck–boost circuit and CLCL resonant circuit is proposed in this paper. The two circuits achieved an effective integration as well as kept their respective working conditions through the switch integration. Interleaving buck–boost circuit with symmetrical structure worked in discontinuous-conduction mode, achieving high power factor and low harmonic distortion. This structure can reduce the input current ripple and balance the current stress of switch at the same time. Besides, the bus voltage was also reduced. The CLCL resonant circuit has a soft-switching characteristic, the primary side operates in zero voltage mode and the secondary side operates in zero current mode. In addition, due to the small turn-OFF current, the turn-off loss of switch was also reduced. Therefore, the system efficiency was high. This paper elaborated the working mode, analysis and design method of the proposed topology. Finally, a 100-W experimental prototype was built, and the experimental results were corresponded with the theoretical analysis.
01 Feb 2019
TL;DR: A quadratic buck-boost converter with positive load terminal voltage with broad span of the output voltage and continuous output current is introduced, which decreases the current stress on the load terminal capacitor.
Abstract: This paper introduces a quadratic buck-boost converter with positive load terminal voltage. Compared to conventional buck-boost converter, the voltage ratio of the introduced topology is squared times of the conventional one. Broad span of the output voltage is one of the advantages of the introduced topology. The continuity of the input current makes this type of converters convenient for renewable energy sources. Continuous output current is another advantage of introduced converter, which decreases the current stress on the load terminal capacitor. Principle operations and steady state analysis are done in continuous current mode. Eventually, the implementation of the introduced topology is evaluated on simulation outcomes.
17 Mar 2019
TL;DR: This paper focuses on analysis and operating modes for a interleaved boost cascaded-by buck (IBCBB) converter suitable for a power factor correction (PFC) converter and a two-stage universal battery charger with wide input and output voltage.
Abstract: In both battery operated electric vehicles (EVs) and plug-in-hybrid electric vehicles (PHEVs), a two-stage converter connects the input grid voltage to the battery pack whose voltage varies from 100-500 V, depending on the vehicle size and range. A universal charger, which can address this wide range of battery pack voltages, is suitable for all vehicle architectures. This requirement is achieved by varying the AC/DC converter output voltage using the concept of variable dc link voltage, which is one of the challenges in battery chargers for attaining universal output voltages. This paper mainly focuses on analysis and operating modes for a interleaved boost cascaded-by buck(IBCBB) converter suitable for a power factor correction (PFC) converter. The designed control structure provides a wide degree of control freedom to operate even if the V DC /V max (output voltage to peak of Input) less than 0.5. The design considerations for selection of components is also addressed in the paper. Moreover, the proposed converter is validated on the experimental setup and the results are presented in the paper. In addition, a two-stage universal battery charger with wide input and output voltage is been simulated and presented in the paper.
TL;DR: In this paper, an isolated buck-boost (IBB) converter with a hybrid three-level full-bridge primary-side circuit is proposed to achieve wider voltage range regulation.
Abstract: An isolated buck–boost (IBB) converter with a hybrid three-level full-bridge primary-side circuit is proposed to achieve wider voltage range regulation. The primary-side circuit is composed of a three-level leg and a two-level leg. The output voltage of the primary-side circuit is five level (i.e., $\pm V_{{\text{in}}}$ , $\pm V_{{\text{in}}}{\text{/ 2}}$ , and zero), and the secondary-side circuit is a semiactive full-bridge rectifier with two active switches and two diodes. The input voltage of the secondary-side circuit is three level (i.e., $\pm V_{{\text{o}}}$ and zero). Hence, the operation voltage range can be wider than the normal IBB converter's with three voltage levels in the primary-side circuit and secondary-side circuit. This paper focuses on the control strategy allowing the converter to operate in boundary current mode at heavy load and in discontinuous current mode at light load with smooth mode transition. The soft-switching performance and output characteristics of the proposed converter are presented in detail. Compared with the semi-dual active bridge converter, the voltage range is doubled and the peak current of the clamped inductor is decreased. An 800-W prototype with 100–400-V input voltage and 380-V output voltage is built and tested to verify the feasibility of the proposed control strategy.
TL;DR: In this article, the authors proposed a new soft-switching non-inverting buck-boost converter (NIBBC) by introducing the magnetic coupling effect to an existing soft switching dc/dc converter.
Abstract: This letter proposed a new soft-switching non-inverting buck–boost converter (NIBBC) by introducing the magnetic coupling effect to an existing soft-switching dc/dc converter. The new NIBBC obtains two superiorities: one magnetic core is removed to improve the efficiency; the magnetic coupling effect can give an adjustable soft-switching range. Operating principles and converter characteristics of the new NIBBC are presented. An experimental prototype of the new NIBBC is built, and switching waveforms and the efficiency are measured. Experimental results show that the new NIBBC can obtain soft-switching conditions and has efficiency improvement comparing to hard-switching converter and another soft-switching dc/dc converter.
TL;DR: This study introduces an advanced DC-DC power converter with two main objectives, (i) to achieve a wide range of voltage gain, which means the converter may work over a widerange of input voltage for a fixed desired output voltage and (ii) to achieved a reduced input current ripple.
Abstract: This study introduces an advanced DC-DC power converter with two main objectives, (i) to achieve a wide range of voltage gain, which means the converter may work over a wide range of input voltage for a fixed desired output voltage and (ii) to achieve a reduced input current ripple. Those features are highly desired in renewable energy applications, for example with photovoltaic panels and fuel cells. The proposed converter was designed in a structure in which the input voltage is composed by the difference of two inductor currents, the currents through inductors are driven with transistors that may have different duty cycle, this allows the current ripple cancellation. In addition, the structure of the converter provides a quadratic type voltage gain, which leads to a wide range of operation voltage. The converter achieves both the wire range of voltage gain and current ripple cancellation, nonetheless, the buck-boost capability is also provided. The input current ripple reduction helps preserve the renewable energy sources since they suffer deterioration when current with considerable ripple is drawn from them. Dynamic and steady-state analysis are performed along with the components sizing. Simulation and experimental results are provided to demonstrate the principle of the proposition.
01 Jan 2019
TL;DR: The right-half-plane (RHP) zero can be eliminated in the proposed buck-boost (BB) converter to achieve fast transients for Internet-of-Thing (IoT) applications and the pseudo-boost mode in the BB converter ensures that the continuous inductor current is half of the conventional design value to achieve 97.46% peak efficiency.
Abstract: The right-half-plane (RHP) zero can be eliminated in the proposed buck-boost (BB) converter to achieve fast transients for Internet-of-Thing (IoT) applications. The pseudo-boost mode in the BB converter eliminates one power switch in the current path and ensures that the continuous inductor current is half of the conventional design value to achieve 97.46% peak efficiency. Besides, the output voltage ripple is reduced to 7mV. By inserting an additional phase, a smooth transition between the buck and pseudo-boost modes ensures a voltage drop less than 15mV. The slope-based transient enhancement (SBTE) circuit accelerates transient response in 9 $\mu$S with a load variation of 400 mA.