Showing papers on "Boost converter published in 2016"
TL;DR: In this article, a family of nonisolated high-voltage-gain dc-dc power electronic converters is proposed, which can be used as multiport converters and draw continuous current from two input sources.
Abstract: A family of nonisolated high-voltage-gain dc–dc power electronic converters is proposed. The suggested topologies can be used as multiport converters and draw continuous current from two input sources. They can also draw continuous current from a single source in an interleaved manner. This versatility makes them appealing in renewable applications such as solar farms. The proposed converters can easily achieve a gain of 20 while benefiting from a continuous input current. Such a converter can individually link a PV panel to a 400-V dc bus. The design and component selection procedures are presented. A 400-W prototype of the proposed converter with $V_{\text{in}} = 20$ and $V_{\text{out}} = 400$ V has been developed to validate the analytical results.
281 citations
TL;DR: In this paper, the authors report switching performance of a new 1700-V, 50-A SiC MOSFET designed and developed by Cree, Inc. and compare it with other SiC devices.
Abstract: Due to wider band gap of silicon carbide (SiC) compared to silicon (Si), MOSFET made in SiC has considerably lower drift region resistance, which is a significant resistive component in high-voltage power devices. With low on-state resistance and its inherently low switching loss, SiC MOSFETs can offer much improved efficiency and compact size for the converter compared to those using Si devices. In this paper, we report switching performance of a new 1700-V, 50-A SiC MOSFET designed and developed by Cree, Inc. Hard-switching losses of the SiC MOSFETs with different circuit parameters and operating conditions are measured and compared with the 1700-V Si BiMOSFET and 1700-V Si IGBT, using same test set-up. Based on switching and conduction losses, the operating boundary of output power and switching frequency of these devices are found out in a dc–dc boost converter and compared. The switching $dv/dts$ and $di/dts$ of SiC MOSFET are captured and discussed in the perspective of converter design. To validate the continuous operation, three dc–dc boost converters using these devices, are designed and tested at 10 kW of power with 1 kV of output voltage and 10 kHz of switching frequency. 1700-V SiC Schottky diode is used as the blocking diode in each case. Corresponding converter efficiencies are evaluated and the junction temperature of each device is estimated. To demonstrate high switching frequency operation, the SiC MOSFET is switched upto 150 kHz within permissible junction temperature rise. A switch combination of the 1700-V SiC MOSFET and 1700-V SiC Schottky diode connected in series is also evaluated for zero voltage switching turn-ON behavior and compared with those of bipolar Si devices. Results show substantial power loss saving with the use of SiC MOSFET.
242 citations
TL;DR: In this paper, a new dc/dc converter is proposed which can produce boosted multiple dc link voltages by using the novel switched-capacitor converter (SCC) and with reduced number of switches.
Abstract: In this paper, initially a new dc/dc converter is proposed which can produce boosted multiple dc link voltages by using the novel switched-capacitor converter (SCC) and with reduced number of switches. In the proposed SCC, voltage of all capacitors is charged by binary asymmetrical pattern as self-balancing and without using any auxiliary circuits. The proposed SCC will boost the input dc power supply voltage without transformer by switching the capacitors in series and in parallel. Next, a new single phase switched-capacitor multilevel inverter (SCMLI) topology which uses the proposed SCC units as virtual dc links have been proposed. The proposed topologies reduce the number of power switches, diodes, isolated dc power supplies, size, and the cost of the system in comparison with conventional similar topologies. For example, by contribution of proposed SCMLI structure, 49 and 137 output voltage levels are made by only 14 and18 power switches and 3 and 4 isolated dc power supplies, respectively. To confirm the performance of proposed topology, various simulation results by PSCAD/EMTDC software and experimental tests are given.
213 citations
TL;DR: The proposed control strategy modifies reaching law (RL) of the sliding mode technique to reduce chattering issue and to improve total harmonic distortion property compared to conventional RL SMC.
Abstract: This paper proposes a sliding-mode control (SMC)-based scheme for the variable-speed direct-driven wind energy conversion systems (WECS) equipped with a permanent magnet synchronous generator connected to the grid. In this paper, diode rectifier, boost converter, neutral point clamped inverter, and L filter are used as the interface between the wind turbine and grid. This topology has abundant features such as simplicity for low- and medium-power wind turbine applications. It is also less costly than back-to-back two-level converters in medium-power applications. The SMC approach demonstrates great performance in complicated nonlinear systems control such as WECS. The proposed control strategy modifies reaching law (RL) of the sliding mode technique to reduce chattering issue and to improve total harmonic distortion property compared to conventional RL SMC. The effectiveness of the proposed control strategy is explored by simulation study on a 4-kW wind turbine, and then verified by experimental tests for a 2-kW setup.
204 citations
TL;DR: A novel bidirectional nonisolated multi-input converter (MIC) topology for hybrid systems to be used in electric vehicles composed of energy storage systems (ESSs) with different electrical characteristics is proposed.
Abstract: To process the power in hybrid energy systems using a reduced part count, researchers have proposed several multiinput dc–dc power converter topologies to transfer power from different input voltage sources to the output. This paper proposes a novel bidirectional nonisolated multi-input converter (MIC) topology for hybrid systems to be used in electric vehicles composed of energy storage systems (ESSs) with different electrical characteristics. The proposed converter has the ability to control the power of ESSs by allowing active power sharing. The voltage levels of utilized ESSs can be higher or lower than the output voltage. The inductors of the converter are connected to a single switch; therefore, the converter requires only one extra active switch for each input, unlike its counterparts, hence resulting in reduced element count. The proposed MIC topology is compared with its counterparts concerning various parameters. It is analyzed in detail, and then, this analysis is validated by simulation and through a 1-kW prototype based on a battery/ultracapacitor hybrid ESS.
191 citations
Journal Article•
TL;DR: In this article, the authors proposed the Alternating Arm Converter Converter (AAC) which is a hybrid between the modular multilevel converter and the two-level converter in the form of director switches in each arm.
Abstract: This paper explains the working principles, sup- ported by simulation results, of a new converter topology intended for HVDC applications, called the alternate arm converter (AAC). It is a hybrid between the modular multilevel converter, because of the presence of H-bridge cells, and the two-level converter, in the form of director switches in each arm. This converter is able to generate a multilevel ac voltage and since its stacks of cells consist of H-bridge cells instead of half-bridge cells, they are able to gen- erate higher ac voltage than the dc terminal voltage. This allows the AAC to operate at an optimal point, called the “sweet spot,” where the ac and dc energy flows equal. The director switches in the AAC are responsible for alternating the conduction period of each arm, leading to a significant reduction in the number of cells in the stacks. Furthermore, the AAC can keep control of the current in the phase reactor even in case of a dc-side fault and support the ac grid, through a STATCOM mode. Simulation results and loss calculations are presented in this paper in order to support the claimed features of the AAC.
158 citations
TL;DR: In this article, an analytical and experimental comparison of a two-phase buck converter and a series capacitor buck converter is presented for high-frequency point-of-load voltage regulators with large voltage conversion ratio (10-to-1) is highlighted.
Abstract: This paper presents an analytical and experimental comparison of a two-phase buck converter and a two-phase, series capacitor buck converter. The limitations of a conventional buck converter in high-current (10 A or more), and high-frequency (HF, 3–30 MHz) point-of-load voltage regulators with large voltage conversion ratios (10-to-1) are highlighted. The series capacitor buck converter exhibits desirable characteristics at HF, including lower switching loss, less inductor current ripple, automatic phase current balancing, duty ratio extension, and soft charging of the energy transfer capacitor. Analysis of the topologies indicates that switching loss and inductor core loss can dominate at HF. Results from side-by-side 12 V input, 1.2 V output hardware prototypes demonstrate that the series capacitor buck converter has up to 12 percentage points higher efficiency at 3 MHz and reduces power loss by up to 33% at full load (10 A). Some guidelines for inductor selection are provided, and a switch stress comparison reveals that the maximum converter switch stress is reduced by 30%.
157 citations
TL;DR: A new transformerless buck-boost converter with simple structure is proposed in this study and its voltage gain is squared times of the former's and its output voltage polarity is positive to enable it to work in a wider range of positive output.
Abstract: A new transformerless buck–boost converter with simple structure is proposed in this study. Compared with the traditional buck–boost converter, the proposed buck–boost converter’s voltage gain is squared times of the former’s and its output voltage polarity is positive. These advantages enable it to work in a wider range of positive output. The two power switches of the proposed buck–boost converter operate synchronously. In the continuous conduction mode (CCM), two inductors are magnetized and two capacitors are discharged during the switch-on period, while two inductors are demagnetized and two capacitors are charged during the switch-off period. The operating principles, the steady-state analyses, and the small-signal model for the proposed buck–boost converter operating in CCM are presented in detail. The power electronics simulator (PSIM) and the circuit experiments are provided to validate the effectiveness of the proposed buck–boost converter.
156 citations
TL;DR: In this paper, a grid-tied photovoltaic (PV) system consisting of modular current-fed dual-active-bridge (CF-DAB) dc-dc converter with cascaded multilevel inverter is proposed.
Abstract: This paper proposes a grid-tied photovoltaic (PV) system consisting of modular current-fed dual-active-bridge (CF-DAB) dc–dc converter with cascaded multilevel inverter. The proposed converter allows a small dc-link capacitor in the three-phase wye-connected PV system; therefore, the system reliability can be improved by replacing electrolytic capacitors with film capacitors. The low-frequency ripple-free maximum power point tracking (MPPT) is also realized in the proposed converter. First of all, to minimize the influence resulting from reduced capacitance, a dc-link voltage synchronizing control is developed. Then, a detailed design of power mitigation control based on CF-DAB dynamic model is presented to prevent the large low-frequency voltage variation propagating from the dc-link to PV side. Finally, a novel variable step-size MPPT algorithm is proposed to ensure not only high MPPT efficiency, but also fast maximum power extraction under rapid irradiation change. A downscaled 5-kW PV converter module with a small dc-link capacitor was built in the laboratory with the proposed control and MPPT algorithm, and experimental results are given to validate the converter performance.
155 citations
TL;DR: The voltage gain of the proposed converter is higher than the conventional cascaded bidirectional buck/boost converter (CCBC) in step-up mode and the efficiency more than CCBC while the total stress on active switches are same.
Abstract: In this paper, a nonisolated bidirectional dc–dc converter is presented. The proposed converter consists of two boost converters to enhance the voltage gain. Four power switches with their body diodes are employed in the proposed converter. Also, two inductors and a capacitor are used as passive components. The input current is divided to the inductors which causes the efficiency to be high. The voltage gain of the proposed converter is higher than the conventional cascaded bidirectional buck/boost converter (CCBC) in step-up mode. Besides, the voltage gain in step-down mode is lower than CCBC. Besides, the efficiency of the proposed converter more than CCBC while the total stress on active switches are same. The simple structure of the proposed converter causes its control to be easy. The steady-state analysis of the proposed converter is discussed in this paper thoroughly. The stress on converters’ devices and the efficiency of the proposed converter and CCBC are compared in this paper. Finally, the proposed converter prototype circuit is implemented to justify the validity of the analysis.
155 citations
TL;DR: A novel high voltage gain, high-efficiency dc-dc converter based on coupled inductor, intermediate capacitor, and leakage energy recovery scheme, which enables the use of low voltage rating switch (with low “on-state” resistance), improving the overall efficiency of the system.
Abstract: Renewable sources like solar photovoltaic (PV) and fuel cell stack are preferred to be operated at low voltages. For applications such as grid-tied systems, this necessitates high voltage boosting resulting in efficiency reduction. To handle this issue, this paper proposes a novel high voltage gain, high-efficiency dc–dc converter based on coupled inductor, intermediate capacitor, and leakage energy recovery scheme. The input energy acquired from the source is first stored in the magnetic field of coupled inductor and intermediate capacitor in a lossless manner. In subsequent stages, it is passed on to the output section for load consumption. A passive clamp network around the primary inductor ensures the recovery of energy trapped in the leakage inductance, leading to drastic improvement in the voltage gain and efficiency of the system. Exorbitant duty cycle values are not required for high voltage gain, which prevents problems such as diode reverse recovery. Presence of a passive clamp network causes reduced voltage stress on the switch. This enables the use of low voltage rating switch (with low “ on -state” resistance), improving the overall efficiency of the system. Analytical details of the proposed converter and its hardware results are included.
TL;DR: In this paper, a 1-MHz 1-kW LLC resonant converter using GaN devices and planar matrix transformers is proposed for data center data center applications, which achieves high-current, high-efficiency, and low-cost power solutions.
Abstract: Data centers demand high-current, high-efficiency, and low-cost power solutions. The high-voltage dc distribution power architecture has been drawing attention due to its lower conduction loss on cables and harnesses. In this structure, the 380–12 V high output current isolated converter is the key stage. This paper presents a 1-MHz 1-kW LLC resonant converter using GaN devices and planar matrix transformers that are designed and optimized for this application. The transformer design and the optimization of the output capacitor termination are performed and verified. Finally, this cost-effective converter achieves above 97% peak efficiency and 700-W/in $^{{{3}}}$ power density.
TL;DR: A novel high step-up nonisolated single switch dc-dc converter suitable for regulating dc bus in various microsources especially for photovoltaic (PV) sources and steady-state analyses are discussed in detail.
Abstract: This paper proposes a novel high step-up nonisolated single switch dc–dc converter suitable for regulating dc bus in various microsources especially for photovoltaic (PV) sources. Quadratic boost and switched-capacitor technique are used as primary and secondary circuits, respectively. A coupled inductor is applied to make a connection between them, so a high dc voltage gain is achieved. High efficiency is yield where voltage stress on active switch is alleviated by clamped capacitor; consequently, smaller $\rm{R}_{\rm{DS(ON)}}$ for power switch is required. On the other hand, input current of the proposed converter is continued, hence stress on the input source is reduced. The operating principles and steady-state analyses are discussed in detail for both continuous and discontinuous conduction modes. Also, the boundary condition is computed. To verify the performance of the proposed converter and theoretical calculations, a 250-W prototype converter is implemented with an input voltage of 24 V and an output voltage of 400 V designed especially for PV sources in continuous conduction mode operation. Finally, simulation results are confirmed by experimental results; maximum efficiency is occurred at 150 W and full-load efficiency is 92.96%.
07 Jun 2016
TL;DR: In this article, the authors evaluate the performance of two types of converters, the line commutated converter LCC and the voltage source converter VSC, and evaluate their operational characteristics, power rating capability, control capability and losses.
Abstract: High Voltage Direct Current (HVDC) systems has been an alternative method of transmitting electric power from one location to another with some inherent advantages over AC transmission systems. The efficiency and rated power carrying capacity of direct current transmission lines highly depends on the converter used in transforming the current from one form to another (AC to DC and vice versa). A well configured converter reduces harmonics, increases power transfer capabilities, and reliability in that it offers high tolerance to fault along the line. Different HVDC converter topologies have been proposed, built and utilised all over the world. The two dominant types are the line commutated converter LCC and the voltage source converter VSC. This review paper evaluates these two types of converters, their operational characteristics, power rating capability, control capability and losses. The balance of the paper addresses their applications, advantages, limitations and latest developments with these technologies.
TL;DR: A dual-active half-bridge (DAHB) converter is integrated into a conventional buck-boost BDC to extend the voltage gain dramatically and decrease switch voltage stresses effectively and zero-voltage switching (ZVS) is achieved for all the active switches to reduce the switching losses.
Abstract: A soft-switching bidirectional dc–dc converter (BDC) with a coupled-inductor and a voltage doubler cell is proposed for high step-up/step-down voltage conversion applications. A dual-active half-bridge (DAHB) converter is integrated into a conventional buck-boost BDC to extend the voltage gain dramatically and decrease switch voltage stresses effectively. The coupled inductor operates not only as a filter inductor of the buck-boost BDC, but also as a transformer of the DAHB converter. The input voltage of the DAHB converter is shared with the output of the buck-boost BDC. So, PWM control can be adopted to the buck-boost BDC to ensure that the voltage on the two sides of the DAHB converter is always matched. As a result, the circulating current and conduction losses can be lowered to improve efficiency. Phase-shift control is adopted to the DAHB converter to regulate the power flows of the proposed BDC. Moreover, zero-voltage switching (ZVS) is achieved for all the active switches to reduce the switching losses. The operational principles and characteristics of the proposed BDC are presented in detail. The analysis and performance have been fully validated experimentally on a 40–60 V/400 V 1-kW hardware prototype.
TL;DR: In this article, a continuous mixed $p$ -norm (CMPN) algorithm-based adaptive control strategy with the purpose of enhancing the low voltage ride through (LVRT) capability of grid-connected photovoltaic (PV) power plants is presented.
Abstract: This paper presents a novel application of continuous mixed $p$ -norm (CMPN) algorithm-based adaptive control strategy with the purpose of enhancing the low voltage ride through (LVRT) capability of grid-connected photovoltaic (PV) power plants. The PV arrays are connected to the point of common coupling (PCC) through a DC-DC boost converter, a DC-link capacitor, a grid-side inverter, and a three-phase step up transformer. The DC-DC converter is used for a maximum power point tracking operation based on the fractional open circuit voltage method. The grid-side inverter is utilized to control the DC-link voltage and terminal voltage at the PCC through a vector control scheme. The CMPN algorithm-based adaptive proportional-integral (PI) controller is used to control the power electronic circuits due to its very fast convergence. The proposed algorithm updates the PI controller gains online without the need to fine tune or optimize. For realistic responses, the PV power plant is connected to the IEEE 39-bus New England test system. The effectiveness of the proposed control strategy is compared with that obtained using Taguchi approach-based an optimal PI controller taking into account subjecting the system to symmetrical, unsymmetrical faults, and unsuccessful reclosing of circuit breakers due to the existence of permanent fault. The validity of adaptive control strategy is extensively verified by the simulation results, which are carried out using PSCAD/EMTDC software. With the proposed adaptive-controlled PV power plants, the LVRT capability of such system can be improved.
TL;DR: A new structure for multi-input multi-output (MIMO) dc-dc boost converter is proposed that has possibility of using energy supplies with different voltage-current characteristics, continuous input current, high voltage gain without high duty cycle, and possibility of performing at high switching frequencies.
Abstract: In this study, a new structure for multi-input multi-output (MIMO) dc-dc boost converter is proposed. The number of inputs and outputs of the converter are arbitrary and independent from each other. The proposed topology has the advantages of both dc-dc boost and switched-capacitor converters. This converter is proper to use in applications like photovoltaic or fuel cell systems. The main advantages of the proposed structure are possibility of using energy supplies with different voltage-current characteristics, continuous input current, high voltage gain without high duty cycle, and possibility of performing at high switching frequencies. First, the different operating modes of the proposed converter are explained. Then, the effect of equivalent series resistance (ESR) of the inductor and voltage drop of diodes and switches on the voltage gain is investigated. Finally, the correctness operation of the proposed converter is reconfirmed by the simulation and experimental results.
TL;DR: In this paper, the authors presented a high-frequency high-efficiency GaN device-based interleaved critical current mode (CRM) bidirectional buck/boost converter with an inverse coupled inductor.
Abstract: This paper presents a high-frequency high-efficiency GaN device-based interleaved critical current mode (CRM) bidirectional buck/boost converter with an inverse coupled inductor. The switching frequency is continually driven to megahertz range with GaN devices due to their small switching loss and driving loss, which greatly reduces the size of the passive components. The coupled inductor further reduces the core volume due to certain dc flux reductions. The equivalent inductance and the impact of the inverse coupled inductor on the CRM buck–boost converter are analyzed in detail. The resonant period in CRM is less with an inverse coupled inductor than with a noncoupled inductor, which is beneficial for the high-frequency operation. The soft-switching range and the circulating energy are both improved using an inverse coupled inductor in CRM. Experimental results validate the theoretical analysis, and the coupled inductor prototype efficiency is 98.5% at 1 MHz, which is 0.3% higher than a prototype with a noncoupled inductor.
TL;DR: In this paper, a non-isolated interleaved dc-dc boost converter with zero voltage switching was proposed, which is designed around a coupled inductor with an active-clamping circuit arrangement to reuse the leakage energy and reduce voltage stress on the semiconductor devices.
Abstract: The requirement for high-voltage gain step-up dc–dc converters is increasingly becoming important in many modern power supply applications They are an essential power conversion stage in systems, such as grid-connected renewables and electric vehicles Unfortunately, achieving a low cost, high efficiency, power dense, step-up converter with high-voltage gain is not a trivial task; yet they are highly desirable when aiming for a green power supply solution For this reason, this paper presents a new nonisolated interleaved dc–dc boost converter with zero voltage switching The proposed converter is designed around a coupled inductor with an active-clamping circuit arrangement to recycle the coupled inductor leakage energy and reduce the voltage stress on the semiconductor devices The lack of isolation transformer improves the power density of the system Likewise, the interleaved circuit allows for high efficiency over a broad range of operating conditions The theoretical behavior of the power converter is fully described, and the performance of the circuit is validated through experimental results Importantly, the circuit is capable of achieving $> 10\times $ voltage gains without the need to apply extreme modulation signals to the pulse width modulation circuit
TL;DR: In this article, a single-series circuit with one double diode on a low-cost, lossy FR-4 substrate was proposed for RF energy harvesting, where rectennas were connected in series configuration (voltage summing), forming rectenna arrays.
Abstract: This work presents an efficient and high-sensitivity radio frequency (RF) energy harvesting supply. The harvester consists of a single-series circuit with one double diode on a low-cost, lossy FR-4 substrate, despite the fact that losses decrease RF harvesting efficiency. The design targeted minimum reflection coefficient and maximum rectification efficiency, taking into account not only the impedance matching network, but also the rectifier microstrip trace dimensions and the load. The simulated and measured rectenna efficiency was 28.4% for $-\hbox{20-dBm}$ power input. In order to increase sensitivity, i.e., ability to harvest energy and operate at low power density, rectennas were connected in series configuration (voltage summing), forming rectenna arrays. The proposed RF harvesting system ability was tested at various input power levels, various sizes of rectenna arrays, with or without a commercial boost converter, allowing operation at RF power density as low as 0.0139 $\mu \hbox{W/cm}^{2}$ . It is emphasized that the boost converter, whenever used, was self-started, without any additional external energy. The system was tested in supplying a scatter radio sensor, showing experimentally the effect of input power density on the operational cold start duration and duty cycle of the sensor.
TL;DR: Through the proposed VBC coordination, the controllable balancing region is extended so that additional balancing circuits are eliminated and the quality of the grid-side currents is improved as the NPC converter has more freedom to control currents.
Abstract: The development of high-power charging stations with fast chargers is a promising solution to shorten the charging time for electric vehicles (EVs). The neutral-point-clamped (NPC) converter-based bipolar-dc-bus-fed charging station brings many merits, but it has inherent voltage balance limits. To solve this issue, a voltage balance control (VBC) method based on a new modulation together with three-level (TL) dc–dc converter-based fast charger is proposed. Additionally, an effective VBC coordination between the TL dc–dc converter and the NPC converter is formulated. Through the proposed VBC coordination, the controllable balancing region is extended so that additional balancing circuits are eliminated. Meanwhile, the quality of the grid-side currents is improved as the NPC converter has more freedom to control currents. The low-frequency voltage fluctuations in dc buses are removed because the TL dc–dc converter performs most of the balancing tasks. Faster VBC perturbation performance is achieved due to higher available balancing current at TL dc–dc converter side. In addition, the voltage balance limits of both the TL dc–dc converter and the NPC converter are explored. The voltage balancing performances are compared when VBC is located at different sides. Simulation and experimental results are provided to verify the proposed VBC and the VBC coordination.
TL;DR: In this article, a control strategy for power flow management of a grid-connected hybrid photovoltaic (PV) and wind-battery-based system with an efficient multi-input transformer-coupled bidirectional dc-dc converter is presented.
Abstract: In this paper, a control strategy for power flow management of a grid-connected hybrid photovoltaic (PV)–wind-battery-based system with an efficient multi-input transformer-coupled bidirectional dc–dc converter is presented. The proposed system aims to satisfy the load demand, manage the power flow from different sources, inject the surplus power into the grid, and charge the battery from the grid as and when required. A transformer-coupled boost half-bridge converter is used to harness power from wind, while a bidirectional buck-boost converter is used to harness power from PV along with battery charging/discharging control. A single-phase full-bridge bidirectional converter is used for feeding ac loads and interaction with the grid. The proposed converter architecture has reduced number of power conversion stages with less component count and reduced losses compared with existing grid-connected hybrid systems. This improves the efficiency and the reliability of the system. Simulation results obtained using MATLAB/Simulink show the performance of the proposed control strategy for power flow management under various modes of operation. The effectiveness of the topology and the efficacy of the proposed control strategy are validated through detailed experimental studies to demonstrate the capability of the system operation in different modes.
TL;DR: In this article, a switched-coupled-inductor quasi-Z-source inverter (SCL-qZSI) is proposed, which integrates a switch-capacitor and a three-winding switched-Coupled Inductive inductor into a conventional qZSI.
Abstract: Z-source inverters have become a research hotspot because of their single-stage buck–boost inversion ability, and better immunity to EMI noises. However, their boost gains are limited, because of higher component-voltage stresses and poor output power quality, which results from the tradeoff between the shoot-through interval and the modulation index. To overcome these drawbacks, a new high-voltage boost impedance-source inverter called a switched-coupled-inductor quasi-Z-source inverter (SCL-qZSI) is proposed, which integrates a switched-capacitor and a three-winding switched-coupled inductor (SCL) into a conventional qZSI. The proposed SCL-qZSI adds only one capacitor and two diodes to a classical qZSI, and even with a turns ratio of 1, it has a stronger voltage boost-inversion ability than existing high-voltage boost (q)ZSI topologies. Therefore, compared with other (q)ZSIs for the same input and output voltages, the proposed SCL-qZSI utilizes higher modulation index with lower component-voltage stresses, has better spectral performance, and has a lower input inductor current ripple and flux density swing or, alternately, it can reduce the number of turns or size of the input inductor. The size of the coupled inductor and the total number of turns required for three windings are comparable to those of a single inductor in (q)ZSIs. To validate its advantages, analytical, simulation, and experimental results are also presented.
TL;DR: In this paper, the authors presented a novel interleaved high-conversion-ratio bidirectional dc-dc converter based on switched capacitors and coupled inductors, where series-connected switched capacitor and inductor cells were used to increase the voltage conversion ratio, reduce voltage stresses on power switches, realize soft-charging/discharging of switched capacitor, and achieve autocurrent-sharing in parallel inductors.
Abstract: This paper presents a novel interleaved high-conversion-ratio bidirectional dc–dc converter based on switched capacitors and coupled inductors. Series-connected switched capacitor and inductor cells were used to increase the voltage conversion ratio, reduce voltage stresses on power switches, realize soft-charging/discharging of switched capacitors, and achieve autocurrent-sharing in parallel inductors. The interleaved structure combined with switched capacitors was adopted to reduce current ripple at the side having lower voltage, thus enabling applications that require high power levels. In this paper, we first review the status of high-voltage-ratio bidirectional dc–dc converters. Then, the evolution of the proposed extensible topologies and the steady-state operating principle under the inductor current continuous conduction mode is presented. Finally, the performance and features such as voltage gain, voltage and current stress, and the autocurrent-sharing mechanism that are realized by switched capacitors are verified; the optimal design of coupled-inductors, switched-capacitors, and the chip size of switches are given. A specific design of the driving circuit that facilitates actual applications is described. A 1-kW prototype converter, employing a hybrid configuration of S iC and Si mosfet s, was constructed to verify the theoretical analysis, and achieved an optimal compromise between conversion efficiency and low cost.
TL;DR: In this article, a novel high step-up converter, which is suitable for a renewable energy system, is proposed, which consists of the dual switches structure, three-winding coupled inductor, and two voltage multiplier cells in order to achieve the high step up voltage gain.
Abstract: A novel high step-up converter, which is suitable for a renewable energy system, is proposed in this paper. The proposed converter is composed of the dual switches structure, three-winding coupled inductor, and two voltage multiplier cells in order to achieve the high step-up voltage gain. The dual switches structure is beneficial to reduce the voltage stress and current stress of the switch. In addition, two multiplier capacitors are, respectively, charged during the switch-on period and switch-off period, which increases the voltage conversion gain. Meanwhile, the energy stored in the leakage inductor is recycled with the use of clamped capacitors. Thus, two main power switches with low on-resistance and low current stress are available. As the leakage inductor, diode reverse-recovery problem is also alleviated. Therefore, the efficiency is improved. This paper illustrates the operation principle of the proposed converter; discusses the effect of the leakage inductor; analyzes the influence of parasitic parameters on the voltage gain and efficiency, the voltage stresses and current stresses of power devices are shown; and a comparison between the performance of the proposed converter and the previous high step-up converters is performed. Finally, the prototype circuit with input voltage 20 V, output voltage 200 V, and rated power 200 W is operated to verify its performance.
TL;DR: In this paper, a hybrid boosting converter with collective advantages of regulation capability from its boost structure and gain enhancement from its voltage multiplier structure is proposed, which makes it suitable for front-end PV system and some other renewable energy applications.
Abstract: A hybrid boosting converter (HBC) with collective advantages of regulation capability from its boost structure and gain enhancement from its voltage multiplier structure is proposed in this paper. The new converter incorporates a bipolar voltage multiplier, featuring symmetrical configuration, single inductor and single switch, high gain capability with wide regulation range, low component stress, small output ripple and flexible extension, which make it suitable for front-end PV system and some other renewable energy applications. The operation principal, component stress, and voltage ripple are analyzed in this paper. Performance comparison and evaluation with a number of previous single-switch single-inductor converters are provided. A 200-W 35 to 380 V second-order HBC prototype was built with peak efficiency at 95.44%. The experimental results confirms the feasibility of the proposed converter.
TL;DR: In this paper, a method for deriving soft-switching three-port converters (TPCs), which can interface multiple energy, is proposed, where the switching bridges on the primary side are shared; hence, the number of active switches is reduced.
Abstract: A systematic method for deriving soft-switching three-port converters (TPCs), which can interface multiple energy, is proposed in this paper. Novel full-bridge (FB) TPCs featuring single-stage power conversion, reduced conduction loss, and low-voltage stress are derived. Two nonisolated bidirectional power ports and one isolated unidirectional load port are provided by integrating an interleaved bidirectional Buck/Boost converter and a bridgeless Boost rectifier via a high-frequency transformer. The switching bridges on the primary side are shared; hence, the number of active switches is reduced. Primary-side pulse width modulation and secondary-side phase shift control strategy are employed to provide two control freedoms. Voltage and power regulations over two of the three power ports are achieved. Furthermore, the current/voltage ripples on the primary-side power ports are reduced due to the interleaving operation. Zero-voltage switching and zero-current switching are realized for the active switches and diodes, respectively. A typical FB-TPC with voltage-doubler rectifier developed by the proposed method is analyzed in detail. Operation principles, control strategy, and characteristics of the FB-TPC are presented. Experiments have been carried out to demonstrate the feasibility and effectiveness of the proposed topology derivation method.
TL;DR: Through the process of fuzzification, inference, and defuzzification, the MPPT system can achieve the merits of good transient tracking capability and better steady-state property and the advantages of auto-scaling variables of ASVSS method and fuzzy-logic control are integrated so that the performance of the solar system can be further improved.
TL;DR: This paper proposes a new five-level voltage source inverter for medium-voltage high-power applications based on the upgrade of a four-level nested neutral-point clamped converter that has high-quality output voltage and fewer components compared to other classic five- level topologies.
Abstract: This paper proposes a new five-level voltage source inverter for medium-voltage high-power applications. The proposed inverter is based on the upgrade of a four-level nested neutral-point clamped converter. This inverter can operate over a wide range of voltages without the need for connecting power semiconductor in series, has high-quality output voltage and fewer components compared to other classic five-level topologies. The features and operation of the proposed converter are studied and a simple sinusoidal PWM scheme is developed to control and balance the flying capacitors to their desired values. The performance of the proposed converter is evaluated by simulation and experimental results.
TL;DR: In this paper, a concept of active filter integration for single-phase AC/DC converters is reported, which can provide simultaneous functions of power factor correction, DC voltage regulation, and active power decoupling for mitigating the lowfrequency DC voltage ripple, without an electrolytic capacitor and extra power switch.
Abstract: Existing methods of incorporating an active filter into an AC/DC converter for eliminating electrolytic capacitors usually require extra power switches. This inevitably leads to an increased system cost and degraded energy efficiency. In this paper, a concept of active-filter integration for single-phase AC/DC converters is reported. The resultant converters can provide simultaneous functions of power factor correction, DC voltage regulation, and active power decoupling for mitigating the low-frequency DC voltage ripple, without an electrolytic capacitor and extra power switch. To complement the operation, two closed-loop voltage-ripple-based reference generation methods are developed for controlling the energy storage components to achieve active power decoupling. Both simulation and experiment have confirmed the eligibility of the proposed concept and control methods in a 210-W rectification system comprising an H-bridge converter with a half-bridge active filter. Interestingly, the end converters (Type I and Type II) can be readily available using a conventional H-bridge converter with minor hardware modification. A stable DC output with merely 1.1% ripple is realized with two 50-μF film capacitors. For the same ripple performance, a 900-μF capacitor is required in conventional converters without an active filter. Moreover, it is found out that the active-filter integration concept might even improve the efficiency performance of the end converters as compared with the original AC/DC converter without integration.