input-parallel output-series(IPOS) connected inverter systems, constructed from connecting multiple inverter modules in parallel at the input side and in series at the output side, are very suitable for high output vo...
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ISBN:
(纸本)9781728180717
input-parallel output-series(IPOS) connected inverter systems, constructed from connecting multiple inverter modules in parallel at the input side and in series at the output side, are very suitable for high output voltage and high power dcac conversion applications. In order to make the IPOS systems work normally, the input current sharing(ICS) and output voltage sharing(OVS) among the constituent modules should be ensured. By analyzing the relationship of the ICS and OVS in terms of power conservation, this paper proposes a compound control strategy, which can achieve ICS and OVS simultaneously. Then a practical realization of the compound strategy, namely, three-loop control scheme, is proposed. This control scheme achieves ICS and phase synchronization of the module output voltage. Decoupling of the control loops is also presented. Finally, the simulation results are given to verify the effectiveness of the compound control strategy.
Wireless power transfer (WPT) technology has shown its significant role in various applications, such as electric vehicles and consumer electronics. In this paper, an input-paralleloutputseries circuit topology based...
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Wireless power transfer (WPT) technology has shown its significant role in various applications, such as electric vehicles and consumer electronics. In this paper, an input-paralleloutputseries circuit topology based on a compact double-sided decoupled coupler is presented to upgrade the power capacity of the WPT system with low-power and low-cost semiconductors. To avoid the potential risk ofmagnetic saturation, the phase difference between the transmitter currents is controlled to be 90 degrees to achieve a symmetrical magnetic flux distribution for the magnetic coupler. Most importantly, an analytical model, which illustrates the relation between the efficiency and the ratio of the output voltages of the transmitter-side inverters under various misalignments, has been derived. Based on this, a control strategy is developed to maximize the energy efficiency under various misalignment conditions. The experimental results based on a 2.5-kW laboratory prototype show that, in comparison with the traditional method with identical inverters output voltages, the overall efficiency is improved by 2.32% by using the proposed method.
input-parallel output-series (IPOS)-based combined converter is usually used in the situation with low input voltage and high output voltage to satisfy the requirements in switch voltage stress reduction and power exp...
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input-parallel output-series (IPOS)-based combined converter is usually used in the situation with low input voltage and high output voltage to satisfy the requirements in switch voltage stress reduction and power expansion. In such a system, the voltage balance of filter capacitor in the output side or current sharing in the input side usually used to guarantee the control performance of the conversion system. In this paper, a phase-shifted full bridge (PSFB)-based IPOS converter with modified connection of output filter circuit used for the wide variation of input voltage is proposed, which is beneficial to reduce ripple current of filter inductor significantly. A control scheme using the same phase shifting for the two different modules of this IPOS converter is detailedly investigated with both steady state and small signal model-based analysis, it manifests that special voltage balance and current sharing control scheme are not necessary for IPOS system under the common phase shifting control method. And the small signal transfer functions of this topology used for dual loop control system design are also developed. The simulation and experiment results are presented to validate the analysis and control scheme.
An input-parallel, output-series dc-dc Boost converter with a wide input voltage range is proposed in this paper. An interleaved structure is adopted in the input side of this converter to reduce input current ripple....
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An input-parallel, output-series dc-dc Boost converter with a wide input voltage range is proposed in this paper. An interleaved structure is adopted in the input side of this converter to reduce input current ripple. Two capacitors are connected in series on the output side to achieve a high voltage gain. The operating principles and steady-state characteristics of the converter are presented and analyzed in this paper. A 400 V/1.6 kW prototype has been created which demonstrates that a wide range of voltage gain can be achieved by this converter and it is shown that the maximum efficiency of the converter is 96.62% and minimum efficiency is 94.14%. The experimental results validate the feasibility of the proposed topology and its suitability for fuel cell vehicles.
High voltage gain dc-dc converters are required in many industrial applications such as photovoltaic and fuel cell energy systems, high-intensity discharge lamp (HID), dc back-up energy systems, and electric vehicles....
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High voltage gain dc-dc converters are required in many industrial applications such as photovoltaic and fuel cell energy systems, high-intensity discharge lamp (HID), dc back-up energy systems, and electric vehicles. This paper presents a novel input-parallel output-series boost converter with dual coupled inductors and a voltage multiplier module. On the one hand, the primary windings of two coupled inductors are connected in parallel to share the input current and reduce the current ripple at the input. On the other hand, the proposed converter inherits the merits of interleaved series-connected output capacitors for high voltage gain, low output voltage ripple, and low switch voltage stress. Moreover, the secondary sides of two coupled inductors are connected in series to a regenerative capacitor by a diode for extending the voltage gain and balancing the primary-parallel currents. In addition, the active switches are turned on at zero current and the reverse recovery problem of diodes is alleviated by reasonable leakage inductances of the coupled inductors. Besides, the energy of leakage inductances can be recycled. A prototype circuit rated 500-W output power is implemented in the laboratory, and the experimental results shows satisfactory agreement with the theoretical analysis.
input-parallel output-series (IPOS) inductive power transfer (IPT) system is suitable for high output voltage, high power or flexible output power levels applications. This paper makes a thorough study of the IPOS IPT...
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ISBN:
(纸本)9781479966103
input-parallel output-series (IPOS) inductive power transfer (IPT) system is suitable for high output voltage, high power or flexible output power levels applications. This paper makes a thorough study of the IPOS IPT system consisting of two modules. Considering the transformation of each module's equivalent load, the cross coupling between two transformers in IPOS system, the analysis of the output voltage gain and the input impedance is performed in the paper. This paper also researches the placement of the two transformer to reduce the cross coupling between the two contactless transformers. A 7 kW IPOS IPT prototype comprising two modules with interleaving control technique is fabricated with the maximum efficiency reaching 95.4%.
The topology of photovoltaic (PV) power system is categorized on the basis of number of power processing stages. The single-stage dc-dc converter has the advantage of simple structure and high efficiency, however it m...
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ISBN:
(纸本)9781479906925
The topology of photovoltaic (PV) power system is categorized on the basis of number of power processing stages. The single-stage dc-dc converter has the advantage of simple structure and high efficiency, however it must handle all tasks itself, i.e., maximum power point tracking and, perhaps, voltage amplification. Instead, the control system of the dual-stage dc-dc converter is simple but its complex structure affects its efficiency. Also the architecture of the PV power systems also affects the efficiency greatly. So in this paper, a new architecture with an input-parallel-output-series isolated dc-dc converter is proposed. In this architecture, most of the PV power is directly transferred to the DC bus through the dc transformer and the voltage difference between the PV string and the fixed DC bus is compensated by a power compensator. Thus, a high efficiency can be reached. A 1 kW prototype is built and tested in the lab. The experimental results are presented to verify the validation of the effectiveness of the proposed PV architecture.
In this paper, a modular multiple DC (MMDC) transformer based DC transmission system, which is used for permanent magnetic synchronous generator (PMSG) based offshore wind farm grid connection, is proposed. The MMDC t...
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In this paper, a modular multiple DC (MMDC) transformer based DC transmission system, which is used for permanent magnetic synchronous generator (PMSG) based offshore wind farm grid connection, is proposed. The MMDC transformer is composed of input-parallel output-series (IPOS) DC/DC submodule groups, each of which consists of several input-seriesoutput-series (ISOS) LLC resonant converters (i.e., submodules). In the offshore wind farm, the electrical power generated by PMSG is converted to DC power by diode rectifier. Compared with the existing offshore wind farm grid-connection schemes, the proposed system has advantages of fewer conversion stages, higher efficiency and lower cost. The mathematical relationship of the system is studied, and then one kind of control strategy is proposed. Furthermore, a detailed DC transmission system simulation model containing a 160 submodules (LLC resonant converters) based MMDC transformer is built in PSCAD/EMTDC. Finally, a down-scaled experimental prototype of the DC system, which includes 9 submodules, is presented. Both simulation and experimental results validate the feasibility of the proposed DC system and effectiveness of the control strategy.
Electric Vehicles (EVs) play a significant role in the reduction of CO2 emissions and other health-threatening air pollutants Accordingly, several research studies are introduced owing to replacing conventional gasoli...
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Electric Vehicles (EVs) play a significant role in the reduction of CO2 emissions and other health-threatening air pollutants Accordingly, several research studies are introduced owing to replacing conventional gasoline-powered vehicles with battery-powered EVs. However, the ultra-fast charging (UFC) of the battery pack or the rapid recharging of the battery requires specific demands, including both: the EV battery and the influence on the power grid. In this regard, advanced power electronics technologies are emerging significantly to replace the currently existing gas station infrastructures with the EV charging stations to move from conventional charging (range of hours) to UFC (range of minutes). Among these power electronics conversion systems, the DC-DC conversion stage plays an essential role in supplying energy to the EV via charging the EV's battery. Accordingly, this paper aims to present possible architectures of connecting multiple Dual Active Bridge (DAB) units as the DC-DC stage of the EV fast charger and study their Small-Signal Modeling (SSM) and their control scheme. These are, namely, input-seriesoutput-series (ISOS), input-seriesoutput-parallel (ISOP), input-paralleloutput-parallel (IPOP), and input-parallel output-series (IPOS). The control scheme for each system is studied through controlling the output filter inductor current such that the current profile is based on Reflex Charging (RC). The main contribution of this paper can be highlighted in providing generalized SSM as well as providing a generalized control approach for the input-seriesinput-parallel output-seriesoutput-parallel (ISIP-OSOP) connection. The generalized model is verified with three different architectures. The control strategy for each architecture is studied to ensure equal power sharing, where simulation results are provided to elucidate the presented concept considering a three-module ISOS, IPOP, ISOP, and IPOS DC-DC converters.
Modular converters have been drawing more attention in recent years and are widely used in various applications such as undersea observatories, smart grid and telecommunication. input-parallel output-series configurat...
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Modular converters have been drawing more attention in recent years and are widely used in various applications such as undersea observatories, smart grid and telecommunication. input-parallel output-series configuration of dc-dc converters has dragged much attention in power electronic transformers and photovoltaic systems. In this paper, proportional integral and fuzzy logic controllers are applied to modular flyback converters in an output-seriesinput-parallel configuration and the performance compared. The performance of the controllers is evaluated and the results reveal that the said configuration is viable.
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