Converters with AC transformer intermediate link suitable as interfaces for supercapacitor energy storage

Nowak, M.; Hildebrandt, J.; Luniewski, P.

doi:10.1109/pesc.2004.1355196

Cited by 19 publications

(20 citation statements)

References 2 publications

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“…• voltage systems referred to the energy storages as supercapacitors (SES) and battery trays [17,[20][21][22][23][24][25][26][27]], • current systems for SMES energy storage type [28][29][30][31][32][33][34], In those solutions an active rectifier is connected to the grid [28], which results from the requirement of bi-directional energy flow of an energy storage, operating directly with bi-directional DC-DC converter [14]. This solution provides both powering and returning energy to the grid with unity power factor.…”

Section: Selected Converter Topologies For Interfacing Energy Storagementioning

confidence: 99%

Selected converter topologies for interfacing energy storages with power grid

Domino

Zymmer

Parchomiuk

2017

Bulletin of the Polish Academy of Sciences Technical Sciences

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Abstract. The paper presents different solutions applicable in power converter systems for connecting power grids with energy storage systems such as superconducting magnetic energy storage (SMES), supercapacitor energy storage (SES) or chemical batteries. Those systems are characterized by bidirectional current flow between energy storage and power grid. Two-level converters (AC-DC and DC-AC converters) dedicated for low power energy storage compatible with 3£400 V-type power grids are proposed. High power systems are connected with 3£6 kV-type power grids via transformers that adjust voltage to the particular energy storage or directly, based on multilevel power converters (AC-DC and DC-AC) or dual active bridge (DAB) systems. Solutions ensuring power grid compatibility with several energy storage systems of the same electrical parameters as well as of different voltage-current characteristics are also proposed. Selected simulation results illustrating operation of two system topologies of 200 kW power for two-level converter and neutral point clamped (NPC) three-level converter are presented.Key words: power converter, superconducting magnetic energy storage (SMES), supercapacitor energy storage (SES), distribution system. Selected converter topologies for interfacing energy storages with power gridA. DOMINO, K. ZYMMER * , and M. PARCHOMIUK Electrotechnical Institute, 28 Pożaryskiego St., 04-703 Warsaw, Poland bility of limiting the temporary increases in power drawn from the grid during start-up of high-power equipment and operation under overload. Note that the hybrid group of energy storage systems with different current-time characteristics, described in this paper, can assure simultaneous compensation of the peak power and long overload state. The peak power is an essential parameter of the electricity tariff in industrial plants. The systems coupling power grid with energy storage can be divided into two groups:• voltage systems referred to the energy storages as supercapacitors (SES) and battery trays [17,[20][21][22][23][24][25][26][27]], • current systems for SMES energy storage type [28][29][30][31][32][33][34], In those solutions an active rectifier is connected to the grid [28], which results from the requirement of bi-directional energy flow of an energy storage, operating directly with bi-directional DC-DC converter [14]. This solution provides both powering and returning energy to the grid with unity power factor. The paper discusses selected topologies of converter systems connecting the energy storage and power grid with different rating parameters using transformers and transformer-less solutions. Converter topologies for interfacing energystorages with grid 2.1. Topology 1. The basic scheme of the arrangement is shown in Fig. 1, where superconducting choke is used as the energy storage element -SMES. The system consists of an AC-DC converter connected to the power grid and the bi-directional DC-DC converter in the form of the pulse current regulator [13]. It is also possible to use battery ...

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Section: Selected Converter Topologies For Interfacing Energy Storagementioning

confidence: 99%

Selected converter topologies for interfacing energy storages with power grid

Domino

Zymmer

Parchomiuk

2017

Bulletin of the Polish Academy of Sciences Technical Sciences

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“…A simple method to achieve these currents is to power supply the transformer from H-bridge converter in the cases: short -circuit operation (triangular shape), resistive load operation (exponential shape) and an inductive -load rectifier connected to the secondary winding (trapezoidal shape). For these waveforms, the RMS values of the individual winding current harmonics relative to the RMS value of the base harmonic are: I (3) /I (1) = 0.1 ÷ 0.25; I (5) /I (1) = 0.05 ÷ 0.1; I (7) /I (1) = 0.02 ÷ 0.05; I (9) /I (1) = 0.015 ÷ 0.02; I (11) /I (1) = 0.01 ÷ 0.015. Although the AC winding resistances for each of the current harmonics are higher than for the base current components (Table 2), the power losses in the copper caused by the harmonics of the order k > 3 are negligible.…”

Section: Analytical Description Of Power Losses In a Transformer Opermentioning

confidence: 99%

“…In the DAB converter the transformer provides the galvanic isolation of both coupled DC circuits, but also the possibility of energy exchange in the case of large differences between the DC voltages. In addition, these voltages may fluctuate, which is characteristic of storage and renewable energy sources [4,5]. An important application field of these converters is also automotive and aeronautical engineering, where there are multi-voltage DC systems [6,7].…”

Section: Introductionmentioning

confidence: 99%

Analytical description of power losses in a transformer operating in the dual active bridge converter

Barlik

Nowak

Grzejszczak

et al. 2016

Bulletin of the Polish Academy of Sciences Technical Sciences

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Abstract. The paper presents an analytical approach to the determination of power losses in a high-frequency transformer operating in the dual active bridge (DAB). This transformer, having two single-phase transistor bridge inverters, couples two DC circuits that significantly differ in voltages (280 V and 51 V ±20%). Power losses in the core and windings of the planar transformer 5600 VA /100 kHz were calculated taking into account changes in the value and direction of the energy flow between the coupled DC circuits. These circuits represent storage or renewable energy sources and intermediate circuits of the converters used in distributed generation systems. Calculations were performed using the Steinmetz's and Dowell's equations. The analytical results have been verified experimentally.Key words: core and windings losses, ferrite, planar transformer, Steinmetz's equation, Dowell's model, dual active bridge. determining the power losses in the core and windings of high frequency transformers. However, the results reported in these publications are obtained in an experimental way and confirmed using a complex analytical description, which is difficult to use in practice. In a number of publications (e.g. [11,[13][14][15]17]), attention is paid to the impact of the growth of the winding resistance for the harmonic current of the transformer, but with no reference to the operation in the DAB system. This paper presents the analytical determination of the power losses in the core and windings of the high-frequency transformer which operates in a dual active bridge. For the determination of these losses, the Steinmetz and Dowell models were used [18,19]. The results of the power losses calculations include the influence of the transformer temperature different relationships between the DC voltages and varying shift modulation ratios of the DAB converter. Analytical description of power losses in a transformerSection 2 presents an overview of a DAB system that includes the transformer being the main subject of this study. Section 3 provides a description of the construction of the transformer and its basic parameters. Sections 4 and 5 are devoted to the discussion of the analytical models used to determine the power loss, as well as the presentation of the results of calculations of the losses in the core and windings of the transformer under consideration. Section 6 provides the results of calculations of the total power loss and transformer energy efficiency with respect to the DAB system. In Section 7, the results obtained analytically and the results of experimental measurements are compared. Section 8 is a summary of the study, containing a brief assessment of the results and conclusions regarding the suitability of the proposed analytical description. The dual active bridge (DAB)Among different versions of dual active bridges, the most commonly presented in the literature are single-phase systems. They

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“…These power converters were based in two types of categories: isolated and non-isolated [2]. Regarding the isolated topologies they are characterized by high number of switching devices [3,4]. On other hand, these topologies normally suffer from high switching losses of the power switches.…”

Section: Introductionmentioning

confidence: 99%

Bidirectional DC-DC converter with high voltage gain for the charge/discharge control of storage systems

Pires

Foito

Martins

2016

2016 15th Biennial Baltic Electronics Conference (BEC)

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Abstract-This paper presents a study of a bidirectional dc-dc converter with high voltage gain to regulate the charge and discharge of electrochemical storage systems. The converter is characterized by quadratic voltage gain characteristics in both directions. In this context it can be used to regulate a dc interface between the storage system and a dc/ac converter connected to the electrical grid. It will be analysed the converter in ideal and non-ideal conditions. A control system to regulate the output voltages and currents are also proposed. Simulation results are presented in order to validate the control system associated to the converter for the charge/discharge of the storage system.

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Converters with AC transformer intermediate link suitable as interfaces for supercapacitor energy storage

Cited by 19 publications

References 2 publications

Selected converter topologies for interfacing energy storages with power grid

Selected converter topologies for interfacing energy storages with power grid

Analytical description of power losses in a transformer operating in the dual active bridge converter

Bidirectional DC-DC converter with high voltage gain for the charge/discharge control of storage systems

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