Novel Integrated Three-Port Bidirectional DC/DC Converter for Energy Storage System
TL;DR: The integrated three-port bidirectional dc/dc converter is a combination of a boost–flyback, forward converter, and voltage doubler and has the following advantages: 1) it operates in input continuous current and low voltage stress; 2) it provides input current recovery; 3) it improves high reverse voltage caused by the transformer; 4) it operating in zero current switching (ZCS); and 5) its doubler circuit can flexibly adjust the dc bus voltage.
Abstract: The study proposes a novel integrated three-port bidirectional dc/dc converter for energy storage systems. The converter includes two batteries, namely 24- and 48-V batteries, used as input source and for backup energy, respectively. Each battery can supply to dc load in the normal case. When the grid power fails, 24-V battery input is stepped up to the dc bus through a high step-up converter. The 48-V battery serves as a buffer power supply when the load increases instantaneously. At night, when the 48-V battery is under low power consumption, the dc bus can charge the battery. In addition, the converter can monitor both battery voltages simultaneously; when one battery is used excessively, the other battery can charge it, thus keeping the system power stable. The integrated three-port bidirectional dc/dc converter is a combination of a boost-flyback, forward converter, and voltage doubler and has the following advantages: 1) it operates in input continuous current and low voltage stress; 2) it provides input current recovery; 3) it improves high reverse voltage caused by the transformer; 4) it operates in zero current switching (ZCS); and 5) its doubler circuit can flexibly adjust the dc bus voltage. A 500-W three-port bidirectional dc/dc device was implemented to verify the feasibility and practicability of the proposed converter. The highest efficiency achieved for operation in 24-V battery high step-up mode was 95.3%; it was 94.9% and 95.2% in 48-V battery step-up and step-down mode, respectively.
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TL;DR: In this article, a non-isolated three-port dc-dc converter with high voltage conversion ratio is proposed, which can be utilized in the renewable energy conversion systems such as in photovoltaic and fuel cells.
Abstract: In this article, a nonisolated three-port dc–dc converter with high voltage conversion ratio is proposed. In the proposed converter, by changing the place of input voltage source between each of the three ports, three different single-input two-output operation modes are achieved. The input current ripple of the proposed converter is eliminated at the low voltage side for the whole range of duty cycles. The voltage conversion ratios of the proposed converter can be increased by increasing the turns ratio of second winding of coupled inductors. Moreover, the proposed converter has achieved proper output voltage regulations for all output ports, simultaneously. The proposed converter can be utilized in the renewable energy conversion systems such as in photovoltaic and fuel cells. In this article, the voltage conversion ratios of the output ports, the voltage stress on switches, the average currents of switches and inductors, and the required condition for cancelling input current ripple at low voltage side are calculated theoretically. The theoretical results are verified and experimental results for 24 V input voltage and 304 V, 240 V output voltages with 400 W power are extracted for two different operation modes.
48 citations
Cites background from "Novel Integrated Three-Port Bidirec..."
...In [26]–[28], three-port dc–dc converters based on coupled inductors are presented....
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TL;DR: Based on battery applications in energy storage systems, in order to make the voltage gain range of LLCL meet the requirements while minimizing the resonant tank currents, a parameter design method is conducted.
Abstract: In this paper, a bidirectional inductor-inductor-capacitor-inductor (LLCL) resonant dc-dc converter is presented. Compared with the conventional LLC, a parallel-connected inductors structure is employed into the resonant tank. By virtue of this unique resonant tank, LLCL exhibits the following desirable features: 1) good voltage gain regulation capability in bidirectional power flow applications; 2) zero-voltage-switching turn-on of the power switches in a wide load range; 3) compared with the other bidirectional LLC-type resonant converters, lower resonant tank currents and lower resonant capacitor voltage stress are achieved under the same working conditions. The topology derivation and operating principles of LLCL are shown, and the vital characteristics of LLCL are especially discussed. Moreover, based on battery applications in energy storage systems, in order to make the voltage gain range of LLCL meet the requirements while minimizing the resonant tank currents, a parameter design method is conducted. Finally, a 500-W prototype is established to verify the operating principles and design effects of the proposed converter.
14 citations
Cites background from "Novel Integrated Three-Port Bidirec..."
...In addition, BDCs can also transmit bidirectional power between the dc bus and the batteries [4]....
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TL;DR: In this article, a three-port converters (TPC) for smooth transitions of 7 distinctive operating modes, depending on sources and loads scheduling, is presented and two viable converter configurations have been identified and selected for further analysis and design of PV-battery systems.
Abstract: This paper presents the design of three-port converters (TPCs) for smooth transitions (i.e., fast settling time, and no obvious overshoot/undershoot) of 7 distinctive operating modes, depending on sources and loads scheduling. Two viable converter configurations have been identified and selected for further analysis and design of PV-battery systems. Conventionally, mode transition is achieved by assigning specific switching patterns through feedback signals and appropriate control algorithms. This incurs a delay in the response and unavoidable noise in the circuit. Additionally, in TPCs, three voltage sensors and three current sensors are generally required for decision making in mode selection, where errors in sensors may lead to an inaccurate response. This paper presents a new control strategy where the number of switching patterns is significantly reduced to 3 patterns instead of minimum 5 patterns for existing reported topologies. Therefore, decisions are simplified so that the transition occurs naturally based on the power availability and load demand but not deliberately as in the conventional method. In addition, instead of six sensors, three voltage sensors and only one current sensor are required to achieve all the necessary operations, namely, MPPT, battery protection, and output regulation. Moreover, these sensors do not participate in mode selection decision, which leads to seamless and fast mode transition. In addition, this work considers two bidirectional ports as compared with only one bidirectional port in most reported topologies. This configuration enables both standalone and DC grid-connected applications. Experimental results are reported to verify the proposed solution.
13 citations
TL;DR: This study provides details on the principle of operation, static gain, control strategy, design guide and experimental verification of the double boost-flyback converter, which has the potential to be used in low input voltage applications that require a high gain.
Abstract: A high-gain step-up non-isolated dc–dc converter is proposed in this study, named the double boost-flyback converter. The topology combines two conventional boost-flyback converters with input-parallel and floating-output connections. The new topology increases the static gain and reduces the input current ripple in relation to the conventional boost-flyback topology. The proposed converter has the potential to be used in low input voltage applications that require a high gain, such as systems powered by photovoltaic panels, fuel cells, electric vehicles, and low voltage batteries. This study provides details on the principle of operation, static gain, control strategy, design guide and experimental verification. A 1 kW prototype was designed and built for an input voltage of 48 V and an output voltage of 800 V, reaching a static gain of 16.67. The maximum efficiencies obtained were 94.6% at 70% of load and 93.9% at rated load.
8 citations
TL;DR: In this paper , a modular MIMO high step-up transformerless DC-DC converter is proposed, which can expand the number of ports from both input and output terminals.
Abstract: In this paper, a Multi-Input Multi-Output (MIMO) high step-up transformerless DC-DC converter is proposed. The proposed converter can expand the number of ports from both input and output terminals. Also, it has a modular structure using voltage multiplier cells (a switch, two diodes, a capacitor, and an inductor). The proposed converter is useful for a wide range of applications and has the merit of interfacing multiple hybrid voltage sources with each other to supply different loads with various voltage levels. All the output voltages of the output ports can be regulated at the same time by tuning separate controlling parameters. Since digital control has the benefit of (1) enhancing efficiency, (2) higher flexibility than analog electronics, (3) ease of use, (4) improving reliability and stability in hybrid energy conversion applications, this method of controlling implementation is adopted. The key contributions of this article would be 1) expandable modular MIMO converter with high performance for all range of duty cycles; 2) integration of hybrid energy sources and delivering to multiple loads; 3) nonlinear digital controlling approach to achieve fast transient response under the variation of input voltage sources and output loads, and 4) high voltage gain with low normalized power stress on switches. To simplify the analysis, first, single-input, dual-output (SIDO) mother-module, dual-input, three-output (DITO) and three-input, four-output (TIFO) developed modules are carefully analyzed and then, the MIMO structure is explained. To verify the theoretical results, a prototype of SIDO operation of the proposed converter with a digital controlling scheme is implemented for 30V input voltage /150V, 250V output voltages with the total power of 450W. Furthermore, experimental results of DITO operation with 30V and 40V input voltages/150V, 250V, 405V output voltages with the total power of 800W are extracted.
7 citations
References
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Book•
21 May 1993
TL;DR: In this article, the authors present an overview of three-phase transformers and their application in DC-DC Converters, including the following: 1. Power Semiconductor Diodes and Circuits 2. Power Transistors 3. Diode Rectifiers 4. Power Supplies. 5. DC Drives.
Abstract: 1. Introduction. 2. Power Semiconductor Diodes and Circuits. 3. Diode Rectifiers. 4. Power Transistors. 5. DC-DC Converters. 6. Pulse-width Modulated Inverters. 7. Thyristors. 8. Resonant Pulse Inverters. 9. Multilevel Inverters. 10. Controlled Rectifiers. 11. AC Voltage Controllers. 12. Static Switches. 13. Flexible AC Transmission Systems. 14. Power Supplies. 15. DC Drives. 16. AC Drives. 17. Gate Drive Circuits. 18. Protection of Devices and Circuits. Appendices: Three-phase Circuits, Magnetic Circuits, Switching Functions of Converters, DC Transient Analysis, Fourier Analysis, Thyristor Commutation Techniques, Data Sheets.
2,055 citations
"Novel Integrated Three-Port Bidirec..." refers background in this paper
...viding 24-V and 48-V batteries to supply theDC load [1]–[9]....
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TL;DR: In this paper, a dual-mode resonant converter topology is proposed for parallel connected dc MICs, which can change resonant modes adaptively depending on the panel operation conditions.
Abstract: The future renewable electric energy delivery and management (FREEDM) system provides a dc interface for alternative energy sources. As a result, photovoltaic (PV) energy can be easily delivered through a dc/dc converter to the FREEDM system's dc bus. The module-integrated converter (MIC) topology is a good candidate for a PV converter designed to work with the FREEDM system. This paper compares the parallel connected dc MIC structure with its counterpart, the series connected MIC architecture. From the presented analysis, the parallel connected architecture was shown to have more advantages. In this paper, a high-efficiency dual mode resonant converter topology is proposed for parallel connected dc MICs. This new resonant converter topology can change resonant modes adaptively depending on the panel operation conditions. The converter achieves zero-voltage switching for primary-side switches and zero-current switching for secondary-side diodes for both resonant modes. The circulation energy is minimized particularly for 5-50% of the rated power level. Thus, the converter can maintain a high efficiency for a wide input range at different output power levels. This study explains the operation principle of the proposed converter and presents a dc gain analysis based on the fundamental harmonic analysis method. A 240-W prototype with an embedded maximum power point tracking controller was built to evaluate the performance of the proposed converter. The prototype's maximum efficiency reaches 96.5% and an efficiency increase of more than 10% under light load conditions is shown when compared with a conventional LLC resonant converter.
274 citations
TL;DR: The control and modulation method for B3C has been proposed for realizing maximum power point tracking (MPPT), battery management, and bus voltage regulation simultaneously, and can be transited between conductance mode and MPPT mode automatically according to the load power.
Abstract: In order to interface one photovoltaic (PV) port, one bidirectional battery port, and one load port of a PV-battery dc power system, a novel nonisolated three-port dc/dc converter named boost bidirectional buck converter (B3C) and its control method based on three-domain control are proposed in this paper. The power flow and operating principles of the proposed B3C are analyzed in detail, and then, the dc voltage relation between three ports is deduced. The proposed converter features high integration and single-stage power conversion from both PV and battery ports to the load port, thus leading to high efficiency. The current of all three ports is continuous; hence, the electromagnetic noise can be reduced. Furthermore, the control and modulation method for B3C has been proposed for realizing maximum power point tracking (MPPT), battery management, and bus voltage regulation simultaneously. The operation can be transited between conductance mode and MPPT mode automatically according to the load power. Finally, experimental verifications are given to illustrate the feasibility and effectiveness of the proposed topology and control method.
178 citations
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
141 citations
TL;DR: In this paper, a three-port converter with high-voltage gain for stand-alone renewable power system applications is proposed, which uses only three switches to achieve the power flow control.
Abstract: In this paper, a novel three-port converter (TPC) with high-voltage gain for stand-alone renewable power system applications is proposed. This converter uses only three switches to achieve the power flow control. Two input sources share only one inductor. Thus, the volume can be reduced. Besides, the conversion ratio of the converter is higher than other TPCs. Thus, the degree of freedom of duty cycle is large. The converter can have a higher voltage gain for both low-voltage ports with a lower turns ratio and a reasonable duty ratio. The voltage stress of switches is low; thus, conduction loss can be further improved by adopting low Rds(on) switches. Therefore, the converter can achieve a high conversion ratio and high efficiency at the same time. The operation principles, steady-state analysis, and control method of the converter are presented and discussed. A prototype of the proposed converter with a low input voltage 24 V for photovoltaic source, a battery port voltage 48 V, and an output voltage 400 V is implemented to verify the theoretical analysis. The power flow control of the converter is also built and tested with a digital signal processor.
135 citations
"Novel Integrated Three-Port Bidirec..." refers background or methods in this paper
...By using a common power switch and a diode to achieve a set of power supplies, power can be simultaneously supplied to the remaining two sets of the bidirectional output circuits [10]–[18], and the advantages of continuous input current of the booster circuit and high step-up are maintained....
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...three-port bidirectional DC/DC converters include high voltage gain boost-buck three-port bidirectional conversion circuits [18], and three-port bidirectional single-storage inductor DC/DC conversion circuits [19]....
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