Showing papers on "Inductor published in 2020"
TL;DR: The principle of operation, the theoretical analysis and the experimental results of a laboratory prototype for N(N2/N1) = 2 and n = 2 stage in about 260W with operating at 40kHz are provided.
Abstract: In this study, a new non-isolated high voltage gains dc/dc converter using coupled inductor and voltage multiplier techniques (diode/capacitor) is presented The voltage gain will be increased by increasing the turns ratio (N) and the number of stages of the VM units The proposed converter capable to more increase the output voltage gains with transfer energy which is stored in coupled inductance Also, the voltage multiplier unit causes to further increase in the output voltage level of the proposed converter Besides, the nominal value of the semiconductors is low due to these are clamped to the capacitors available on the voltage multiplier units The normalized voltage stress across the semiconductors is low which this case is compared in the comparison section Therefore, the power loss of switch can be reduced by using a switch with a lower rating (lower RDS(on)) and power diodes with the low nominal rating As a result, the overall efficiency of the proposed converter will be high To confirm the benefits of working in this paper, comparison results for different items with other works are provided in section 4 The principle of operation, the theoretical analysis and the experimental results of a laboratory prototype for N(N2/N1) = 2 and n = 2 stage in about 260W with operating at 40kHz are provided
137 citations
TL;DR: A transformer-less grid-tied single-phase inverter is proposed which is directly connected to the grid, without any output filter, leading to elimination of the losses caused by the filter and increased efficiency.
Abstract: In this paper, a transformer-less grid-tied single-phase inverter is proposed which is directly connected to the topology. The voltage across the leakage capacitor has the base frequency, which decreases the leakage current under the defined value in the standards. This inverter’s active switches are high- and low-frequency types. High-frequency switches control the inductor’s current. In addition, the low-frequency switches are synchronous with the grid and operate in the base frequency. Since no power electrolytic decoupled capacitor is utilized between the high- and low-frequency switches, the system’s total efficiency and lifespan are improved. The proposed inverter has the capability of stepping up/down the output voltage, making it suitable for operating in a wide range of voltages and also providing large range of powers to the grid. This topology is directly connected to the grid, without any output filter, leading to elimination of the losses caused by the filter and increased efficiency. In the proposed inverter, a digital current controller is employed to control the injected current to the grid. Furthermore, P&O algorithm is adapted to extract the maximum power from the input source. For proving the proposed converter’s performance, a 770-W prototype has been implemented and comprehensive experimental results are presented.
127 citations
TL;DR: A high-efficiency, high-power-density Sigma converter for a 48 V rack architecture in data centers is proposed in this paper and can achieve a power density of 420 W/in3 as well as a peak efficiency of 94%.
Abstract: A high-efficiency, high-power-density Sigma converter for a 48 V rack architecture in data centers is proposed in this paper. The Sigma converter is a quasi-parallel converter that uses a high-efficiency unregulated converter to deliver the bulk power to the load. A small buck converter is responsible for regulating the output voltage with prescribed dynamic responses. A design guideline for Sigma converter with integrated magnetics is provided in this paper. The unregulated converter is an LLC converter designed with a printed circuit board (PCB) winding matrix transformer, a structure which integrates four elemental transformers into one core. The buck converter is designed with discrete gallium nitride (GaN) devices and a PCB winding inductor. The proposed Sigma converter operates at 48 V input and 1 V-80 A output and can achieve a power density of 420 W/in3 as well as a peak efficiency of 94%.
103 citations
TL;DR: A new fundamental structure of a single-phase transformer-less grid connected multilevel inverter based on a switched-capacitor structure is presented in this study and a tightly controlled current with an appropriate quality can be injected to the grid using a single source renewable energy resource.
Abstract: A new fundamental structure of a single-phase transformer-less grid connected multilevel inverter based on a switched-capacitor structure is presented in this study. By employing the series-parallel switching conversion of the integrated switched-capacitor module in a packed unit, attractive features for the proposed inverter can be obtained such as high efficiency and boosting ability within a single stage operation. Also, using a common grounding technique provides an additional advantage of reducing the leakage current. Moreover, the presented structure generates a multilevel waveform at the output voltage terminals which reduces the harmonics in the system. A peak current controller is utilized for triggering the gate of the power switches and controlling both the active and reactive powers. This results in a tightly controlled current with an appropriate quality that can be injected to the grid using a single source renewable energy resource. Operating procedures, design considerations, comparison studies and test results of a 620 W prototype are also presented to validate the accuracy and feasibility of the proposed multilevel inverter.
89 citations
TL;DR: In this paper, a single-switch, high step-up, dc-dc converter based on coupled-inductor with three winding and voltage multiplier cell to obtain a very highvoltage conversion ratio was introduced.
Abstract: This article introduces a single-switch, high step-up, dc–dc converter based on coupled-inductor with three winding and voltage multiplier cell to obtain a very high-voltage conversion ratio. A passive clamp circuit is applied in the converter to recycle the energy of leakage inductance and reduce voltage stress of the main power switch. This leads to utilize a power switch with low on-state resistance and low voltage rating that decreases the conduction losses. Several advantages include low operating duty cycle, high voltage conversion ratio, low turn ratio of the coupled inductor, leakage inductance reverse recovery, reduced voltage stress of semiconductors, alleviation of diodes reverse recovery issue and high efficiency, which make the presented topology appropriate for sustainable energy applications such as photovoltaic systems. The operation principle and steady-state analysis of the suggested topology in continuous conduction mode are expressed in detail. Also, design procedure and theoretical efficiency analysis of the proposed topology are presented. Moreover, a comparison study is performed to demonstrate the superiority of the presented converter over several similar recently proposed dc–dc converters. Finally, the proposed dc–dc converter feasibility and performance are justified through a fabricated 216-W laboratory prototype at 50 kHz switching frequency.
83 citations
TL;DR: A new current-sensorless FS-MPC scheme for LC-filtered voltage source inverters, which is flexible to various cost functions and can also reduce the computational cost and the inevitable control delay in digital implementation.
Abstract: A typical finite-set model predictive control (FS-MPC) scheme for LC -filtered voltage source inverters (VSIs) requires measurements of capacitor voltage and inductor current as well as load current measurement or estimation, which increases the system complexity and cost. To reduce the number of sensors in typical FS-MPC, this paper proposes a new current-sensorless FS-MPC scheme for LC -filtered VSIs. First, based on the inner relationship of the predictive matrices, the predictive model is exactly simplified with the capacitor voltage and its current as the state variables, making it suitable for current-sensorless control. Then, to eliminate the current sensors for cost reduction and reliability enhancement, the dynamic model is reconstructed and an easily implemented capacitor current estimator is designed, which can achieve a comparable performance with typical FS-MPC scheme. Considering the inevitable control delay in digital implementation, the delay compensation is inherently obtained by using the proposed estimator. In addition, the proposed control scheme is flexible to various cost functions and can also reduce the computational cost. The feasibility of the presented control scheme under load variations and model mismatches are verified by the comparative simulation and experimental results with typical FS-MPC.
80 citations
TL;DR: The firefly algorithm conveys a leading task for the SLMLI topology for solar-photovoltaic applications and generates low distortion output and consumes the harmonic band of the fast Fourier transform framework by the employment of the proposed algorithm.
Abstract: The super-lift technique is an exceptional contribution to DC-DC conversion technology. A replacement approach of symmetrical super-lift multilevel inverter (SLMLI) DC/AC technology is proposed with a reduced number of elements compared with the traditional multilevel inverter. In this method, the firefly algorithm conveys a leading task for the SLMLI topology for solar-photovoltaic applications. It generates low distortion output and consumes the harmonic band of the fast Fourier transform framework by the employment of the proposed algorithm. The simulation circuit for 15 levels output uses single switch super-lift inverter feed with different kinds of load (R, RL and RLE) conditions. The power quality is improved in SLMLI with minimised harmonics underneath the various modulation indices while varied from 0.1 up to 0.8. The circuit is designed in a field-programmable gate array, which includes the firefly rule to help the multilevel output, to reduce the lower order harmonics and to find the best switching angle. As a result, the minimum total harmonic distortion from the simulation and hardware circuit is achieved. Due to the absence of bulky switches, inductor and filter elements expose the effectiveness of the proposed system.
76 citations
TL;DR: In this paper, a dual half-bridge LLC resonant converter with magnetic control is proposed for the battery charger application, where the primary switches are shared by two LLC Resonant Networks, and their outputs are connected in series.
Abstract: In this paper, a dual half-bridge LLC resonant converter with magnetic control is proposed for the battery charger application. The primary switches are shared by two LLC resonant networks, and their outputs are connected in series. One of the LLC resonant converters is designed to operate at the series resonant frequency, which is also the highest efficiency operating point, and the constant output voltage characteristic is achieved at this operating point. The second LLC resonant converter adopts magnetic control to regulate the total output current and voltage during both constant current charge mode and constant voltage charge mode. Meanwhile, the function decoupling idea is adopted to further improve the system efficiency. The significant amount of the power is handled by the LLC resonant converter operating at the series resonant frequency, whereas the second LLC resonant converter fulfills the responsibility to achieve closed-loop control. By carefully designing the resonant networks, the zero-voltage switching for primary switches and zero-current switching for secondary diodes can be achieved for whole operation range. A 320-W experimental prototype is built to verify the theoretical analysis, and the maximum efficiency is measured about 95.5%.
75 citations
TL;DR: The IPOSB can attain high gain and lower output voltage ripples under a proper duty cycle, and the leakage energy of coupled inductor can also be recycled to the load, so the low voltage level MOSFETs can be adopted to reduce the losses and cost.
Abstract: This paper presents a hybrid cascaded boost converter, in which the input terminal is interlaced in parallel and the output capacitors embedded in voltage multiplier cells are interlaced in series at the output terminal [input parallel output series boost converter (IPOSB)]. The IPOSB can reduce the input current ripples because two primary windings of coupled inductors are connected in parallel with the cross. The voltage multiplier units combine with diode–capacitor and coupled inductor in the output side are charged and discharged in a series and parallel way. In addition, the leakage inductance of the coupled inductor inhibits the inrush current of the capacitors. Therefore, the IPOSB can attain high gain and lower output voltage ripples under a proper duty cycle, and the leakage energy of coupled inductor can also be recycled to the load. At the same time, the voltage stress of power devices is lowered, so the low voltage level MOSFETs can be adopted to reduce the losses and cost. Meanwhile, the soft switching performance of the zero-current-switching is fulfilled, which reduces effectively switching losses. The operational principle and steady-state performance of the converter are analyzed in detail. The correctness of the theoretical analysis is verified by setting up a 450-W experimental prototype.
74 citations
TL;DR: The proposed converter features continuous input current, which is desirable and friendly to the battery, fuel cell, and photovoltaic applications, and the reverse recovery problem of the diodes can be alleviated and leakage energy can be recycled.
Abstract: Analysis and design of a single-switch high step-up coupled-inductor boost converter are presented in this paper. With the aid of the coupled inductor, the proposed converter can achieve high-voltage gain without extreme duty cycle. Also, low switch voltage stress can be achieved, thus low-voltage-rating mosfet is allowed to lower the conduction loss. Moreover, the proposed converter features continuous input current, which is desirable and friendly to the battery, fuel cell, and photovoltaic applications. In addition, the reverse recovery problem of the diodes can be alleviated and leakage energy can be recycled. The operation principles and characteristics of the proposed converter are discussed. Experimental results are provided to verify the theoretical analysis.
72 citations
TL;DR: In this article, a three-phase interleaved structure with switched-capacitor cells is proposed for dc-dc converter with a wide voltage-gain range, low-current ripple on the low-voltage side, low voltage stresses across power switches, an absolute common ground between input and output, and can be easily extended into a topology family.
Abstract: A switched-capacitor interleaved bidirectional dc–dc converter that combines a three-phase interleaved structure with switched-capacitor cells is proposed. The converter features a wide voltage-gain range, low-current ripple on the low-voltage side, low voltage stresses across power switches, an absolute common ground between input and output, and can be easily extended into a topology family. The operating principle and power switch voltage and current stresses are analyzed in detail. An 800 W prototype with a wide voltage-gain range ( U high = 400 V, U low = 30–100 V) is described, demonstrating a maximum efficiency of 95.8% in the step-up mode and 95.9% in the step-down mode.
11 Oct 2020
TL;DR: In this paper, a new optimization method for switching frequency is proposed with a better insulation structure, which is demonstrated on a 200-kHz CLLC converter with 98.7 % efficiency and 61 W/in3 power density.
Abstract: CCG Facility Integration proposed that the 4.16-kVAC power distribution in a data center greatly reduces the loss on cable, especially when compared to 480-VAC distribution. Also, it is suggested that the minimum stage of power conversion is obtained by powering each server rack with a 400-VDC bus that is directly step-downed from the 4.16-kVAC. An input-series-output-parallel (ISOP) structure becomes a promising topology for this power conversion. In addition to the modularity, the medium voltage (MV) is handled by efficient low-voltage devices connected in series, leading to high efficiency and high power density. The transformer in the DC/DC converter is crucial, since it is responsible for the MV insulation. Since insulation occupies a significant space in the transformer, the conventional optimization approach needs to be re-evaluated, especially in regard to switching frequency. The increase in spacing provides the opportunity to integrate the resonant inductor into the transformer. In this paper, a new optimization method for switching frequency is proposed with a better insulation structure. The design is demonstrated on a 200-kHz CLLC converter with 98.7 % efficiency and 61 W/in3 power density.
TL;DR: The principle of operation, theoretical analysis, design methodology, and a comparison of the proposed topology regarding other converters from the literature that use similar principles are approached.
Abstract: A new nonisolated high-step-up dc–dc converter based on active switched-inductors and passive switched-capacitors is proposed in this article. The main advantages of the converter are the high voltage gain (higher than 20), high efficiency, reduced voltage stresses, and reduced component count. This article approaches the principle of operation, theoretical analysis, design methodology, and a comparison of the proposed topology regarding other converters from the literature that use similar principles. Finally, the theoretical study is verified from a 200-W prototype designed to accomplish an input voltage of 20 V and an output voltage of 300 V, in which a peak efficiency of 96.2% is reached.
TL;DR: A new single-inductor MIMO dc–dc converter with a wide conversion ratio is proposed, which allows input sources to be added or removed seamlessly with no cross-regulation problem and the high extension capability for arbitrary inputs/outputs is realized.
Abstract: Multi-input multi-output (MIMO) dc–dc converters can integrate multiple input sources and output loads simultaneously. This article proposes a new single-inductor MIMO dc–dc converter with a wide conversion ratio. The proposed converter allows input sources to be added or removed seamlessly with no cross-regulation problem. Meanwhile, the outputs are independently controlled, i.e., the load change at one output cell will not affect the other interconnected output cells. Constant current control is the main control requirement. When constant current control is applied to all input cells, the power provided by each input source is proportional to the voltage magnitude of the source. When the constant current control is applied to some of the input cells, the input sources with direct duty-cycle controlled input cells can provide specific power through controlling the duty cycles of the switches of the corresponding input cells. Moreover, the switching time of switches is irrelevant. Therefore, it is easy to realize the high extension capability for arbitrary inputs/outputs. A dual-input dual-output prototype is constructed to illustrate the performance of the proposed converter. The corresponding component design is presented.
TL;DR: An optimal design methodology based on time-domain analysis of the LLC resonant converter with magnetic control is proposed and can assure that the converter will operate in PO or OPO modes within the whole operating range, and zero voltage switching operation for primary switches and zero current switching operationfor secondary rectifier will be guaranteed.
Abstract: The LLC resonant converters commonly adopt frequency modulation (FM) or combination of FM with phase-shift modulation to regulate its output voltage. However, in these control schemes, a variable switching frequency range is required, which makes the magnetic components design complicated. Therefore, in this article, magnetic control (or variable inductor control) is adopted to make the converter operating at constant switching frequency and constant duty cycle. The fundamental harmonic analysis is commonly used because of its characteristic of simplicity. However, the accuracy of this method is reduced and considerable errors occur when the switching frequency or output power changes. Therefore, an optimal design methodology based on time-domain analysis of the LLC resonant converter with magnetic control is proposed in this article. The proposed methodology can assure that the converter will operate in PO or OPO modes within the whole operating range, and zero voltage switching operation for primary switches and zero current switching operation for secondary rectifier will be guaranteed. In addition, by limiting the resonant tank root-mean-square current, the system efficiency is improved. A 200-W experimental prototype is built and the effectiveness of the proposed optimal design methodology is verified.
TL;DR: In this article, an LLC converter using gallium nitride (GaN) transistors is proposed for a 48-V regulated and isolated bus converter, which can achieve a power density of 700 W/in3 with a maximum efficiency of 97.82% at half-load, dropping to 97.7% at full-load operation.
Abstract: In this article, an LLC converter using gallium nitride (GaN) transistors is proposed for a 48-V regulated and isolated bus converter. Compared with pulsewidth modulation (PWM)-based topologies, the soft switching capability of an LLC allows operation at very high frequencies. In addition, the size of the magnetic components is reduced without sacrificing the efficiency. In this article, a novel magnetic structure that integrates a matrix transformer and inductor with minimum winding and a single magnetic core is proposed, to allow a high-density and high-efficiency LLC converter design for a bus converter. A 40—60-V input and regulated 12-V output converter is developed to deliver a 1-kW output power in a quarter brick form factor. The designed converter can achieve a power density of 700 W/in3 with a maximum efficiency of 97.82% at half-load, dropping to 97.7% at full-load operation.
TL;DR: The proposed converter achieves a very high step-up voltage gain by using two coupled inductors and a voltage multiplier cell by utilizing the interleaved boost converter in the input side, and the input current is shared with low ripple.
Abstract: This paper proposes a new interleaved non-isolated high step-up dc-dc converter for interfacing renewable energy applications. The proposed converter achieves a very high step-up voltage gain by using two coupled inductors and a voltage multiplier cell. This topology utilizes the interleaved boost converter in the input side, and the input current is shared with low ripple. Moreover, a voltage multiplier cell with the secondary windings of the coupled inductors is employed in the output side to achieve the interleaved energy storage. The voltage stress on the semiconductor switches and the passive components is significantly reduced and lower than the output voltage. The aforementioned converter can be operated without an extreme duty cycle or a high turns ratio. The reverse recovery problem of the diodes is mitigated, and the leakage energy is recycled. Furthermore, by implementing low-voltage-rated MOSFETs with a small ON-resistance, the conduction losses can be reduced, and the efficiency can be improved. The topology is fed by a single input voltage, and the mathematical expression is methodically explored. The operation principle of the proposed converter and the comparison between the proposed converter with other topologies are discussed. The design, parameters selection, and experimental results are thoroughly introduced. A 32 to 800 V-dc is verified and simulated by using PLECS. Consequently, a 400 W hardware prototype is verified to validate the theory and the design.
TL;DR: Experimental results on a SiC-based charger validate the effectiveness of this method of widening ZVS range for output voltage of 200–450 Vdc and power of 0–20 kW, achieving smooth transitions among various operation modes, and suppressing the switch crosstalk, thereby securing high charger reliability.
Abstract: Dual-active-bridge (DAB) circuit is an excellent candidate for a high-efficiency, high-power density, and bidirectional electric vehicle charger. Unlike resonant circuits employing auxiliary inductors and capacitors, DAB minimizes the usage of passive components. The challenge, however, lies in the difficulty of securing zero-voltage switching (ZVS), particularly at light-to-medium load when using the conventional single-phase-shift (SPS) control. This is of utmost importance not only for the sake of the efficiency, but also for minimizing the switch-bridge crosstalk caused by the hard switching- on , thereby enhancing the system reliability. Although dual-phase-shift (DPS) and triple-phase-shift (TPS) can be the answer, they do introduce side effects such as larger switching- off current. This article systematically integrates SPS, DPS, and TPS to maximize full-power ZVS range for both steady state and transient operations in EV chargers. This article plots ZVS boundaries over the full power range, categorizes all operations into nine modes, and proposes a smooth transition method among all operation modes. Dead band is also incorporated in the ZVS boundary setting. Experimental results on a SiC-based charger validate the effectiveness of this method of widening ZVS range for output voltage of 200–450 Vdc and power of 0–20 kW, achieving smooth transitions among various operation modes, and suppressing the switch crosstalk, thereby securing high charger reliability.
TL;DR: A new scheme of single-phase transformerless grid-connected inverter is presented, using the series–parallel switching conversion of the integrated switched-capacitor module in a packed unit, which can be quantified as more than 97% overall efficiency for a wide range of output power.
Abstract: A new scheme of single-phase transformerless grid-connected inverter is presented in this article. By employing the series–parallel switching conversion of the integrated switched-capacitor module in a packed unit, some attractive features for the proposed inverter can be obtained. Such promising features can be quantified as more than 97% overall efficiency for a wide range of output power, two-time boosting ability within a single-stage operation and almost total suppression of the leakage current through using the common grounding technique. In this case, a peak current controller strategy is used in order to trigger the gate of power switches and control both the active and reactive powers. Therefore, a tightly controlled current with an appropriate quality can be injected to the grid from a single source renewable energy resource. Operating procedure, design consideration, comparison study, and a 513 W built prototype results are also given to prove the correctness and feasibility of the proposed circuit.
TL;DR: The proposed ITPS is proved as a promising solution in eliminating the dc-bias current, minimizing the transient current stress by using an improved triple-phase-shift (ITPS) control for DAB converters.
Abstract: A transient dc-bias current due to the voltage-second imbalance of isolated bidirectional dual-active-bridge (DAB) converters for the disturbance in line or load may result in the transformer saturation and oscillations in both sides dc currents. This article focuses on the transient dc-bias current elimination by using an improved triple-phase-shift (ITPS) control for DAB converters. The inductor peak current stress optimization is adopted in the proposed ITPS to determine the steady-state phase-shift variables. Originated from the dc-bias current model of DAB converters with the TPS control, the transient phase-shift adjustment strategy can be determined, which has the ability to improve the inductor current changing slope and shorten the settling time. Both simulation and experiments for different conditions are provided to evaluate main dynamic indexes such as the transient period, dc-bias current, and inductor current stress for three different transition cases. The proposed ITPS is proved as a promising solution in eliminating the dc-bias current, minimizing the transient current stress.
TL;DR: A new family of high gain step up dc-dc converter is proposed, but a generalized methodology to derive them from any classical dc-DC topology by applying a coupled inductor and voltage multiplier cells is proposed.
Abstract: Due to the plethora of non-isolated high gain step-up dc-dc converters presented in the literature, it has become important to comprehensively review and classify them, as well as to derive methods to generalize the usage of the commonly employed techniques. Motivated by this need, this paper not only proposes a new family of high gain step up dc-dc converter, but a generalized methodology to derive them from any classical dc-dc topology by applying a coupled inductor and voltage multiplier cells. For illustrating the methodology, high gain dc-dc converters based on the basic topologies (Buck, Boost, and Buck-Boost) are developed and analyzed. These converters are compared in terms of voltage gain, coupled inductor size, voltage stresses, total device rating, switching frequency effect in power loss, and output power regulation. Moreover, in order to verify the proposal, two practical experimentations are accomplished. Firstly, a prototype able to operate as any of the three basic topologies with different gain cells is developed for comparing theoretical, simulated, and experimental static gain results. Secondly, well-designed prototypes concerning to the Buck-, Boost-, and Buck-Boost-based converters are assembled for efficiency evaluation.
TL;DR: In this paper, a new nonisolated high step-up quasi Z-source (QZS) dc-dc converter with coupled inductor techniques is presented, which is suitable for renewable applications.
Abstract: In this article, a new nonisolated high step-up quasi Z-source (QZS) dc–dc converter with coupled inductor techniques is presented, which is suitable for renewable applications. The main advantages of the proposed topology are continuous input current, common ground between load and input dc source, low normalized voltage stress on the semiconductors (switch/diodes), and low total voltage stress on devices compared to the conventional QZS converter. However, increasing the turns ratio value of the coupled inductor windings not only limit the duty cycle but also leads to decrease the voltage stress on switch/diodes and increase the output voltage level. The operating performance of the proposed converter, theoretical analysis and comparison between the proposed converter and other published works (i.e., QZS converters) are provided. Finally, one prototype at 500 W is built and tested, which shows experimental results and theoretical analysis verify each other well.
TL;DR: The design and implementation of an inverter module that incorporates two individual nine-level FCML single-phase inverters in an interleaved design that decreases the commutation loop inductance of the inverter and allows fast switching with minimal ringing, while also enabling efficient double-sided cooling.
Abstract: Multilevel inverters such as the flying capacitor multilevel inverter (FCML) hold large potential benefit in applications where the size and weight of the inverter is constrained. This article presents the design and implementation of an inverter module that incorporates two individual nine-level FCML single-phase inverters in an interleaved design. Each inverter utilizes GaN field-effect transistors (FETs) switching at 100 kHz for an effective inductor ripple frequency of 800 kHz. The implementation features an innovative dual-sided integrated switching cell layout, which decreases the commutation loop inductance of the inverter and allows fast switching with minimal ringing, while also enabling efficient double-sided cooling. The switching cell layout is particularly well suited for high-voltage applications, as creepage and clearance requirements can be easier met compared to single-sided solutions. The effectiveness of the approach is demonstrated in a hardware inverter prototype intended for driving low-inductance electric machines for future electric aircrafts. The 1000 $\mathbf {V_{dc}}$ to 380 $\mathbf {V_{ac,rms}}$ , 6-kW prototype achieves a peak efficiency of 98.6% and a peak power density of 15 kW/kg.
TL;DR: In this paper, a novel high step-up interleaved dc-dc converter is presented, which is composed of an interleaving structure, an asymmetric voltage multiplier cell (AVMC), and a passive lossless clamped circuit.
Abstract: In this article, a novel high step-up interleaved dc–dc converter is presented, which is composed of an interleaved structure, an asymmetric voltage multiplier cell (AVMC), and a passive lossless clamped circuit. Compared to the classical interleaved boost converter, the proposed converter has a higher voltage gain owing to the employment of the AVMC and the coupled inductor. In addition, the input current ripple is limited to low values with the help of the interleaved structure, which gives more lifetime to the input power source. The voltage stresses of main switches are substantially low so that the MOSFETs with low voltage rate and ON-resistance ( $R_{\textrm {DS}(\mathrm{ON})} $ ) can be used. In addition, the voltage stresses and the reverse recovery problems of diodes are improved dramatically. Moreover, the zero current switching (ZCS) turn-on of switches and the ZCS turn-off of the clamp diodes are realized to reduce the switching losses. The leakage inductor energy is recycled and the voltage spikes are improved greatly by the passive lossless clamped circuit so that the efficiency can be upgraded further. Finally, a 400-W, 40-V-input, 400-V-output prototype is established to demonstrate the performance of this converter. The highest efficiency is about 97.3% and the full-load efficiency is approximately 97%.
TL;DR: A switched capacitor–inductor network (SCLN)-based ultravoltage gain dc–dc converter using a single switch is presented and can achieve ultra dc voltage gain with minimum number of devices when compared with other existing converters.
Abstract: A switched capacitor–inductor network (SCLN)-based ultravoltage gain dc–dc converter using a single switch is presented. The SCLN converter can achieve ultra dc voltage gain with minimum number of devices when compared with other existing converters. Moreover, the voltage gain is significantly improved at entire duty ratios. In addition, due to switched approach of inductor and capacitor, the converter provides lesser ripple content in the output voltage and current. The operation of the converter in continuous conduction mode (CCM) and discontinuous conduction mode (DCM) is discussed. The parasitic elements are considered to estimate the dc voltage gain and the efficiency of the converter more precisely. The small-signal model of the converter is derived, and the pole-zero locations are investigated. Moreover, the comparative performances of the SCLN converter with existing converters are reported. A hardware prototype has been developed and tested. To prove the applications of the SCLN converter in solar PV system, the experimental results are observed by considering the output voltages of 650 V for three-phase and 325 V for single-phase applications.
TL;DR: In this converter, coupled inductors and diode-capacitor voltage multiplier (VM) cells are utilized simultaneously to provide higher voltage gain, which increases the flexibility of the proposed converter.
Abstract: In this article, a new high step-up dc–dc converter with soft-switching capability is presented. In this converter, all of the main and the auxiliary power switches operate under soft-switching condition. In addition, the leakage inductances of the coupled inductors control the current falling rate of the power diodes. Therefore, the reverse recovery losses are reduced significantly. In addition, the voltage stresses across the power semiconductors and clamped capacitors are limited to lower values. In this converter, coupled inductors and diode-capacitor voltage multiplier (VM) cells are utilized simultaneously to provide higher voltage gain. This combination increases the flexibility of the proposed converter, because the turn ratios of the coupled inductors and the number of VM cells are the degrees of freedom which can be used to regulate the voltage stress across the semiconductors. In this article, detailed analysis, elements design, and comparison results are presented. Furthermore, in order to validate the theoretical analysis, a 500-W, 19–60-V/400-V laboratory prototype of the proposed converter is built, and the related results are investigate.
TL;DR: In this paper, the authors investigated the influence of active zero vector pulsewidth modulation (AZPWM-1) and SVPWM on the design of passive common-mode attenuation methods to reduce CM current and shaft voltage in inverter-fed V/f-controlled induction motor drives.
Abstract: This paper investigates the influence of active zero vector pulsewidth modulation (AZPWM-1) and space vector pulsewidth modulation (SVPWM) on the design of passive common-mode (CM) attenuation methods to reduce CM current and shaft voltage in inverter-fed V/f-controlled induction motor drives. The passive CM attenuation methods examined here are the CM choke, the CM electromagnetic interference (EMI) filter, and the CM transformer. The attenuation requirement of AZPWM-1 and SVPWM is identified to design the passive CM choke and EMI filter. Based on the attenuation requirement, the design guidelines are revisited for SVPWM, and design rules are proposed for AZPWM-1. However, the CM transformer is designed based on the step change in magnitude of CM voltage of both the pulsewidth modulations (PWMs). The limitations in design, regarding switching frequency and component size for each case, are also established. It is shown that to have a similar attenuation in the considered two PWM cases, AZPWM-1 requires smaller passive components compared to SVPWM. The proposed design guidelines are substantiated with experimental results on a 1.1-kW induction motor drive.
TL;DR: In this paper, a coupled inductor-based high step-up dc-dc converter is proposed, which benefits from various advantages, namely ultrahigh voltage gain, low voltage stress on the power switches, and continuous input current with low ripple.
Abstract: In this article, a novel coupled inductor-based high step-up dc–dc converter is proposed. The introduced converter benefits from various advantages, namely ultrahigh voltage gain, low voltage stress on the power switches, and continuous input current with low ripple. Therefore, the presented converter is suitable for renewable energy applications. By utilizing clamped circuit, voltage spike of the active switch is clamped during the turn- off process. Hence, a switch with low $R_{\text{DS-on}}$ can be used, which reduces the conduction losses as well as the cost of the converter. Furthermore, the energy of leakage inductance is used to obtain zero voltage switching (ZVS) for the main and auxiliary switches. Additionally, the output diode current falling rate is controlled by leakage inductance; thus, reverse-recovery problem of output diode is alleviated. The steady-state analysis and design considerations of the proposed converter are discussed. Finally, a 250-W experimental prototype of the presented converter is implemented to validate the converter operation and the theoretical analysis.
TL;DR: An integrated interleaved dc–dc converter with ultrahigh voltage gain and reduced voltage stress based on the coupled-inductors and switched-capacitor circuits is proposed in this article, which is suitable for interfacing the low-voltage energy sources with a high- voltage dc bus in electric vehicle applications.
Abstract: An integrated interleaved dc–dc converter with ultrahigh voltage gain and reduced voltage stress based on the coupled-inductors and switched-capacitor circuits is proposed in this article, which is suitable for interfacing the low-voltage energy sources, such as fuel-cell, with a high-voltage dc bus in electric vehicle applications. Input-parallel connection of the coupled-inductors offers a reduced input current ripple and the current rating of components, as well as automatic input current sharing without a dedicated current sharing controller. A promising power-density improvement technique is given, in which only one magnetic core is utilized to implement two coupled-inductors that can provide the filter functionality, as well as transformer behavior. For suppressing the voltage ringing resulting from the leakage inductors, the active-clamp configuration is employed that can facilitate the soft-switching performance for all switches in a wide range of output power. A voltage multiplier stage is adapted to not only boost the voltage gain but help alleviate the reverse-recovery problem of diodes. The steady-state performance, theoretical analysis, and a comparison with the state-of-the-art converters are given in this article. Finally, the experimental results of a 1-kW, 100-kHz prototype are provided to confirm the validity of the proposed concept.
TL;DR: This article proposes a novel step-up interleaved dc–dc converter that is suitable for renewable energy systems and the combination of coupled inductor and built-in transformer voltage multiplier cell gives an extra degree of freedom to increase the voltage gain.
Abstract: This article proposes a novel step-up interleaved dc–dc converter that is suitable for renewable energy systems. Coupled inductor and built-in transformer voltage multiplier cell are applied to extend the voltage gain while increasing the power density. Hence, the step-up ratio can be adjusted by the turns ratios of the coupled inductor and the built-in transformer. Compared with the other converters with only built-in transformer or only coupled inductor, the combination of these techniques gives an extra degree of freedom to increase the voltage gain. The configuration of the proposed converter not only reduces the current stress through the components, but also the input current ripple is maintained at low values that lengthen the life time of the renewable power source. The energy of the leakage inductors is successfully recycled and the high-voltage spikes across the power switches are avoided, which improves the conversion efficiency. Due to the reduced voltage stress, low-voltage power MOSFET s can be adopted for reduction of conduction losses and cost. The principle operation and steady-state analysis are given to explore the advantages of the proposed converter. Finally, a 1-kW prototype with 45–675 V voltage conversion is built to demonstrate the effectiveness of the proposed converter.