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Power Electronics, IEEE Transactions on

Issue 1 • Date Jan. 2014

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Displaying Results 1 - 25 of 56
  • Table of Contents

    Publication Year: 2014 , Page(s): C1 - 2
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  • IEEE Transactions on Power Electronics publication information

    Publication Year: 2014 , Page(s): C2
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  • Editorial for IEEE Transactions on Power Electronics, January 2014

    Publication Year: 2014 , Page(s): 3 - 5
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  • A Hybrid Symmetrical Voltage Multiplier

    Publication Year: 2014 , Page(s): 6 - 12
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (896 KB) |  | HTML iconHTML  

    Voltage multiplier circuits are widely used in many high-voltage/low-current applications. A conventional symmetrical voltage multiplier (SVM) has much better performance, when compared with its half-wave counterpart. However, it requires a high-voltage transformer (HVT) with center-tapped secondary to perform its push-pull kind of operation. The design of an HVT with center-tapped secondary is relatively complex. This paper proposes a hybrid SVM (HSVM) for dc high-voltage applications. The multiplier is formed by cascading a diode-bridge rectifier and an SVM with diode-bridge rectifier as the first stage of multiplier. The proposed topology saves two high-voltage capacitors and requires only one secondary winding of HVT. Besides, it has lesser voltage drop and faster transient response at start-up, when compared with conventional SVM. The feasibility of the proposed HSVM is validated both by simulation and experimental results of a laboratory scaled-down prototype. View full abstract»

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  • The k -Q Analysis for an LLC Series Resonant Converter

    Publication Year: 2014 , Page(s): 13 - 16
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (524 KB) |  | HTML iconHTML  

    The k-Q analysis of the resonant tank for an LLC series-resonant converter (SRC) is presented in this letter. In order to guarantee the LLC-SRC operating region, the k-Q design guideline of the resonant tank is proposed. View full abstract»

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  • Current Sensorless Power Balance Strategy for DC/DC Converters in a Cascaded Multilevel Converter Based Solid State Transformer

    Publication Year: 2014 , Page(s): 17 - 22
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (869 KB) |  | HTML iconHTML  

    This letter proposes a current sensorless controller for balancing the power in the dc/dc stage of a cascaded multilevel converter based solid state transformer. It is revealed that the equalization of the active power component of duty cycles in the cascaded multilevel rectifier stage can be a good indicator of power balance in the dc/dc stage. Additionally, the power balance of the dc/dc stage can guarantee the voltage balance in the rectifier stage if the differences among the power devices are negligible. Based on this principle, a novel power balance controller without sensing any current in the dc/dc stage is proposed. In the end, experimental results in a seven-level three-stage solid state transformer are provided for verifying the proposed method. View full abstract»

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  • AC Power Losses Model for Planar Windings With Rectangular Cross-Sectional Conductors

    Publication Year: 2014 , Page(s): 23 - 28
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (716 KB) |  | HTML iconHTML  

    In this letter, a method to calculate the ac losses, including skin effect and proximity losses, in planar windings with rectangular cross-sectional conductors is proposed. The aim is proposing proper ac losses expressions similar to the formulas available for round cross-sectional wires, to be used for the calculation of the ac losses and the optimization of planar magnetic windings implemented in the printed circuit board. The proposed model is based on the decomposition into conduction and proximity losses. Conduction losses only depend on the properties of the conductor, whereas proximity losses are calculated by using the orthogonal decomposition of the magnetic fields in which the conductors are immersed. Functions including the frequency and geometrical dependences of the both types of losses are extracted by means of finite element method simulation. Finally, several prototypes are used to verify the proposed expressions and some design considerations are also outlined. View full abstract»

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  • MPPT and Voltage Balancing Control With Sensing Only Inductor Current for Photovoltaic-Fed, Three-Level, Boost-Type Converters

    Publication Year: 2014 , Page(s): 29 - 35
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (602 KB) |  | HTML iconHTML  

    In the literature, both photovoltaic voltage and PV current need to be sensed to perform maximum power point tracking (MPPT) control. For three-level boost converter, both capacitor voltages need to be sensed and an additional voltage balancing control loop is required to balance the capacitor voltages. In this paper, the MPPT control and the voltage balancing control with sensing only inductor current is proposed. The provided simulation and experimental results demonstrate the proposed method. View full abstract»

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  • Parameterization of Three-Phase Electric Machine Models for EMI Simulation

    Publication Year: 2014 , Page(s): 36 - 41
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (427 KB) |  | HTML iconHTML  

    A systematic and practical method to parameterize three-phase electric machine models for electromagnetic interference (EMI) simulation is presented. The proposed behavioral model consists of multiple sections of linear RLC circuits and is intended for time-domain simulation with inverters and other power electronic circuits found in typical motor drive systems. The proposed parameterization method uses a differential-mode (DM) and a common-mode (CM) impedance measurement of the machine and takes advantage of the separation among different parallel and series resonant frequencies of each impedance to determine the parameters of each stage in a noniterative manner. The proposed method can also be applied to model three-phase cables and transformers. View full abstract»

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  • A DC Transformer

    Publication Year: 2014 , Page(s): 42 - 44
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (301 KB) |  | HTML iconHTML  

    A component level dc transformer is described in which no alternating currents or voltages are present. It operates by combining features of a homopolar motor and a homopolar generator, both dc devices, such that the output voltage of a dc power supply can be stepped up (or down) with a corresponding step down (or up) in the current. The basic theory for this device is developed, performance predictions are made, and the results from a small prototype are presented. Based on demonstrated technology in the literature, this dc transformer should be scalable to low megawatt levels, but it is more suited to high current than high voltage applications. Significant development would be required before it could achieve the kilovolt levels needed for dc power transmission. View full abstract»

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  • Design and Characterization of an Eight-Phase-137-kW Intercell Transformer Dedicated to Multicell DC–DC Stages in a Modular UPS

    Publication Year: 2014 , Page(s): 45 - 55
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2077 KB) |  | HTML iconHTML  

    Recent uninterruptible power supply (UPS) systems, in the medium power range (a few 100 kW), are based on a three-power stage topology including a rectifier, an inverter, and a dc-dc converter. The dc-dc converter ensures the charger/discharger function necessary for battery management. The monolithic intercell transformer (ICT) described in this paper is dedicated to such a charger/discharger, of which the nominal power is 137 kW. This dc-dc converter is comprised of eight interleaved cells that are interconnected by the ICT. The first part of this paper briefly presents the full UPS system and the topology of the eight-cell charger/discharger arranged around the eight-phase monolithic ICT. The second part suggests a model and emphasizes the design specificities of the monolithic ICT. The final design is provided by an optimization routine, checked in the end by different 2-D and 3-D finite-element simulations, both electromagnetic and thermal. The third part describes the construction of the ICT prototype. It is then placed in a test bench that reproduces the conditions of future operations and provides current balance conditions. Finally, the experimental results obtained for the 137-kW nominal power validate design parameters and confirm the interest of the ICT solution. View full abstract»

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  • Three-Phase Three-Level DC/DC Converter for High Input Voltage and High Power Applications-Adopting Symmetrical Duty Cycle Control

    Publication Year: 2014 , Page(s): 56 - 65
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1032 KB) |  | HTML iconHTML  

    Three-phase dc/dc converters have the superior characteristics including lower current rating of switches, the reduced output filter requirement, and effective utilization of transformers. To further reduce the voltage stress on switches, three-phase three-level (TPTL) dc/dc converters have been investigated recently; however, numerous active power switches result in a complicated configuration in the available topologies. Therefore, a novel TPTL dc/dc converter adopting a symmetrical duty cycle control is proposed in this paper. Compared with the available TPTL converters, the proposed converter has fewer switches and simpler configuration. The voltage stress on all switches can be reduced to the half of the input voltage. Meanwhile, the ripple frequency of output current can be increased significantly, resulting in a reduced filter requirement. Experimental results from a 540-660-V input and 48-V/20-A output are presented to verify the theoretical analysis and the performance of the proposed converter. View full abstract»

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  • A Control Method for Voltage Balancing in Modular Multilevel Converters

    Publication Year: 2014 , Page(s): 66 - 76
    Cited by:  Papers (25)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1706 KB) |  | HTML iconHTML  

    The modular multilevel converter (MMC) is attractive for medium- or high-power applications because of the advantages of its high modularity, availability, and high power quality. The voltage balancing of the floating capacitors in the cascaded submodules of the MMC is a key issue. In this paper, a voltage-balancing control method is proposed. This method uses the phase-shifted carrier-based pulsewidth modulation scheme to control high-frequency current components for capacitor voltage balancing in the MMC without measuring the arm currents. Simulations and experimental studies of the MMC were conducted, and the results confirm the effectiveness of the proposed capacitor voltage-balancing control method. View full abstract»

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  • On Energy Storage Requirements in Modular Multilevel Converters

    Publication Year: 2014 , Page(s): 77 - 88
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (823 KB) |  | HTML iconHTML  

    The modular multilevel converter is a promising topology for high-voltage and high-power applications. By using submodules equipped with dc-capacitors excellent output voltage waveforms can be obtained at low switching frequencies. The rated energy storage of the submodule capacitors is a driving factor of the size, cost, and weight of the submodules. Although the modular multilevel converter has been thoroughly investigated in the literature, a more detailed analysis of the energy-storage requirements will provide an important contribution for dimensioning and analysis of modular multilevel converters. Such an analysis is presented in this paper. The analysis relates the power transfer capability to the stored energy in the converter and the findings are validated by both simulations and experimental results. The required size of the submodule capacitors in a 4.5 MW grid-connected converter is first calculated and the calculated operating range is then compared with simulation results. The experimental results show that if the average capacitor voltage is allowed to increase 10% above the nominal value an energy storage to power transfer ratio of 21 J/kW can be achieved. It is concluded that the presented theory can relate the power transfer capability to the energy storage in the converter and is thus a valuable tool in the design and analysis of modular multilevel converters. View full abstract»

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  • DC Islands in AC Smart Grids

    Publication Year: 2014 , Page(s): 89 - 98
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (910 KB) |  | HTML iconHTML  

    The advantages arising from dc distribution networks are related to the possibilities of achieving higher quality supply and easier reconfigurability of the system. This paper presents the concept of introducing some dc islands interconnected with the ac distribution network. This will make it easier to connect storage systems, electrical drives, power converters, and renewable sources (i.e., photovoltaic panels). In order to realize the aforementioned goals, a methodology for designing the control strategy of different power converters connected to a dc bus without a centralized system management control unit is proposed. In this way, a plug-and-play functionality for connecting new power converter interfaced elements in the dc network able to stabilize the voltage under different working conditions is realized. In order to prove the advantages obtainable with such a network, a 100-kW dc test facility has been realized at the laboratories of RSE. Different working conditions were tested by means both of numerical and experimental results, proving the effectiveness of the proposed strategy for voltage regulation, continuity of service, and the smart use of storage devices. View full abstract»

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  • A DC-Side Current Injection Method for Improving AC Line Condition Applied in the 18-Pulse Converter System

    Publication Year: 2014 , Page(s): 99 - 109
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1460 KB) |  | HTML iconHTML  

    In this paper, a new compensation strategy for receiving clean power of a conventional 18-pulse ac/dc converter formed by three 6-diode bridges is proposed. According to the proposed strategy, a three-phase current-controlled inverter injects the compensation currents into the three positive terminals of the three six-diode bridges. The goal of injecting currents at dc side is to improve the quality of the ac line currents. Compared to the conventional active filter deployed at the ac side, the three-phase inverter used in this paper is with lower kVA rating, and the 18-pulse converter draws nearly sinusoidal currents from the ac main by the proposed compensation strategy. The theoretical compensation command is derived in this paper, and then an approximate approach is recommended to simplify the calculation. A digital-signal processor is employed as a digital controller to calculate the compensation command, and a 3-kW prototype including the 18-pulse converter and the current-controlled inverter is built for evaluation and measurement. Moreover, the performance affected by unbalanced ac source is investigated. The experimental results demonstrate that the proposed method not only improves the line current quality but also mitigates the effects caused by unbalanced source voltages. View full abstract»

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  • Resonance Issues and Damping Techniques for Grid-Connected Inverters With Long Transmission Cable

    Publication Year: 2014 , Page(s): 110 - 120
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1574 KB) |  | HTML iconHTML  

    An infinite source with series inductance is usually employed as a grid emulator in grid-connected distributed generation systems. Thus, high capacitance of a transmission cable (i.e., underground cable) is too significant to be neglected. As a result, the capacitance and inductance may cause system resonance, which, in turn, challenges system stability. This paper takes offshore wind farm as an example to investigate the resonance issues caused by the submarine transmission cable of the grid-connected generation system. Based on the submarine cable model, a series of considerable resonant peaks is found in the open-loop transfer function of the grid-connected system because of the high-order LC configuration. The resonant peaks are sensitive to the system setup, which is clearly investigated. To overcome the resonances, this paper proposes a cascaded notch-filter-based active damping method to guarantee a good system stability and robustness. Furthermore, the proposed controller employs a proportional-resonant component to reduce the steady-state error of the output current. The simulation and experimental results have validated the findings of resonances and the effectiveness of the proposed controller. View full abstract»

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  • Active Mitigation of Subsynchronous Interactions Between PWM Voltage-Source Converters and Power Networks

    Publication Year: 2014 , Page(s): 121 - 134
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1632 KB) |  | HTML iconHTML  

    Pulse-width-modulated (PWM) voltage-source converters (VSCs) are gaining widespread acceptance in modern power systems. It has been shown recently that full-scale high-power PWM VSCs can induce negative electrical damping at subsynchronous frequencies. However, active reshaping of the VSC incremental output impedance to minimize the negative impacts of a VSC on subsynchronous damping is not reported. To fill out this gap, this paper presents: 1) an extended analysis of the output impedance of a PWM-based two-level VSC; and 2) more importantly, three simple and robust active reshaping techniques to maximize the positive electrical damping in the subsynchronous frequencies without affecting the converter control performance. The first reshaping technique uses the grid voltage and an active-damping controller to generate active impedance that modifies the VSC impedance in the subsynchronous range. The second reshaping technique uses an internal active damping controller to modify the dynamics of the phase-locked loop, which has significant contribution to the negative impedance of the VSC. The third reshaping technique combines the first and second techniques. The proposed active mitigation methods show excellent performance in reshaping the VSC impedance and inducing positive electrical damping to mitigate possible subsynchronous interactions between the VSC and the power network. Further, the proposed compensators show robust control performance at different output power levels of the VSC without significant impact on the converter control performance. A theoretical analysis and comparative time-domain simulation and experimental results are presented to verify the validity and effectiveness of the proposed techniques. View full abstract»

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  • 3-D Electromagnetic Modeling of Parasitics and Mutual Coupling in EMI Filters

    Publication Year: 2014 , Page(s): 135 - 149
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1276 KB)  

    The electromagnetic compatibility (EMC) analysis of electromagnetic interference (EMI) filter circuits using 3-D numerical modeling by the partial element equivalent circuit (PEEC) method represents the central topic of this paper. The PEEC-based modeling method is introduced as a useful tool for the prediction of the high frequency performance of EMI input filters, which is affected by PCB component placement and self- and mutual-parasitic effects. Since the measuring of all these effects is rather difficult and time consuming, the modeling and simulation approach represents a valuable design aid before building the final hardware prototypes. The parasitic cancellation techniques proposed in the literature are modeled by the developed PEEC-boundary integral method (PEEC-BIM) and then verified by the transfer function and impedance measurements of the L-C and C-L-C filter circuits. Good agreement between the PEEC-BIM simulation and the measurements is achieved in a wide frequency range. The PEEC-BIM method is implemented in an EMC simulation tool GeckoEMC. The main task of the presented research is the exploration of building an EMC modeling environment for virtual prototyping of EMI input filters and power converter systems. View full abstract»

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  • High-Voltage Gain Boost Converter Based on Three-State Commutation Cell for Battery Charging Using PV Panels in a Single Conversion Stage

    Publication Year: 2014 , Page(s): 150 - 158
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1967 KB) |  | HTML iconHTML  

    This paper presents a novel high-voltage gain boost converter topology based on the three-state commutation cell for battery charging using PV panels and a reduced number of conversion stages. The presented converter operates in zero-voltage switching (ZVS) mode for all switches. By using the new concept of single-stage approaches, the converter can generate a dc bus with a battery bank or a photovoltaic panel array, allowing the simultaneous charge of the batteries according to the radiation level. The operation principle, design specifications, and experimental results from a 500-W prototype are presented in order to validate the proposed structure. View full abstract»

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  • A Fuel Cell Power Conditioning System With Low-Frequency Ripple-Free Input Current Using a Control-Oriented Power Pulsation Decoupling Strategy

    Publication Year: 2014 , Page(s): 159 - 169
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1771 KB) |  | HTML iconHTML  

    This paper proposes a fuel cell power conditioning system based on the current-fed dual-half-bridge (CF-DHB) dc-dc converter that can achieve low-frequency ripple-free input current using a control-oriented power pulsation decoupling strategy when an inverter load is connected to the fuel cell system. Without adding any extra circuit components, the proposed power pulsation decoupling strategy can realize a smaller dc bus capacitor; a film capacitor, therefore, can be applied in this fuel cell power conditioning system to replace the bulky electrolytic capacitor. In order to eliminate the double-frequency ripple current disturbance introduced by the inverter load to the fuel cell stack, a proportional-resonant controller is developed to achieve an extra high control gain at a designed resonant frequency. The operation principles of the CF-DHB converter with a proposed power pulsation decoupling strategy are analyzed. In addition, the controller design guidelines are derived based on the system small-signal model. The experimental results of a 1-kW fuel cell power conditioning system are presented to validate the proposed technology. View full abstract»

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  • Swinging Bus Technique for Ripple Current Elimination in Fuel Cell Power Conversion

    Publication Year: 2014 , Page(s): 170 - 178
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2282 KB) |  | HTML iconHTML  

    A swinging bus scheme is investigated in this paper to eliminate undesirable low-frequency ripple current reflection in fuel cells. The swinging bus is thoroughly characterized under various loading conditions to establish a behavioral model. As a result, a general control scheme and signal processing for buck- and boost-derived power converters are obtained. A digital filter in the form of a moving averaging filter proves to be a fundamental component of the control loop, a significant practical advancement in control for low-frequency ripple elimination. A formal mathematical demonstration is included and experimental results are presented to validate the technique and illustrate its benefits. View full abstract»

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  • Influence of Multijunction Ga/As Solar Array Parasitic Capacitance in S3R and Solving Methods for High-Power Applications

    Publication Year: 2014 , Page(s): 179 - 190
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1173 KB) |  | HTML iconHTML  

    This paper deals with the influence produced by the solar array parasitic capacitance and its solving methods in the sequential switching shunt regulator (S3R). Nowadays, the usage of triple-junction Ga/As solar cells with larger parasitic capacitance has prompted new problems about power losses, steady state, and dynamic response in the S3R, especially for high section current, voltage applications. Effects of parasitic capacitance on voltage ripple, “double sectioning,” phase margin, and output impedance are represented and analyzed, and turn-off delay caused by parasitic capacitance is mathematically modeled. A novel shunt regulator topology passive and active shunt regulator (PASR) with low switching losses, low mass, and short turn-off time delay is proposed. To further reduce the impact of delay, nonlinear control is added in the control loop, achieving better performances in the stability margin, output impedance, and dynamic performance. Simulation and experimental results are provided to validate the proposed PASR together with nonlinear control scheme. View full abstract»

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  • Design for Efficiency Optimization and Voltage Controllability of Series–Series Compensated Inductive Power Transfer Systems

    Publication Year: 2014 , Page(s): 191 - 200
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1462 KB) |  | HTML iconHTML  

    Inductive power transfer (IPT) is an emerging technology that may create new possibilities for wireless power charging and transfer applications. However, the rather complex control method and low efficiency remain the key obstructing factors for general deployment. In a regularly compensated IPT circuit, high efficiency and controllability of the voltage transfer function are always conflicting requirements under varying load conditions. In this paper, the relationships among compensation parameters, circuit efficiency, voltage transfer function, and conduction angle of the input current relative to the input voltage are studied. A design and optimization method is proposed to achieve a better overall efficiency as well as good output voltage controllability. An IPT system design procedure is illustrated with design curves to achieve a desirable voltage transfer ratio, optimizing between efficiency enhancement and current rating of the switches. The analysis is supported with experimental results. View full abstract»

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  • Maximum Power Transfer Tracking for Ultralow-Power Electromagnetic Energy Harvesters

    Publication Year: 2014 , Page(s): 201 - 212
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2109 KB) |  | HTML iconHTML  

    This paper describes the design and operation of power conditioning system with maximum power transfer tracking (MPTT) for low-power electromagnetic energy harvesters. The system is fully autonomous, starts up from zero stored energy, and actively rectifies and boosts the harvester voltage. The power conditioning system is able to operate the harvester at the maximum power point against varying excitation and load conditions, resulting in significantly increased power generation when the load current waveform has a high peak-to-mean ratio. First, the paper sets out the argument for MPTT, alongside the discussion on the dynamic effects of varying electrical damping on the mechanical structure. With sources featuring stored energy, such as a resonant harvester, maximum power point control can become unstable in certain conditions, and thus, a method to determine the maximum rate of change of electrical damping is presented. The complete power conditioning circuit is tested with an electromagnetic energy harvester that generates 600 mV rms ac output at 870 μW under optimum load conditions, at 3.75 m·s-2 excitation. The digital MPTT control circuit is shown to successfully track the optimum operating conditions, responding to changes in both excitation and the load conditions. At 2 V dc output, the total current consumption of the combined ancillary and control circuits is just 22 μA. The power conditioning system is capable of transferring up to 70% of the potentially extractable power to the energy storage. View full abstract»

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Aims & Scope

IEEE Transactions on Power Electronics covers fundamental technologies used in the control and conversion of electric power.

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