scholarly journals Fully Isolated Quad-Port Electric Energy Routing Converter with Medium- and High-Voltage Grid Connection Capability

2022 ◽  
Vol 2022 ◽  
pp. 1-17
Author(s):  
Guanglin Sha ◽  
Qing Duan ◽  
Wanxing Sheng ◽  
Yao Zhang ◽  
Chunyan Ma ◽  
...  
Keyword(s):  
Phase Shift ◽  
High Voltage ◽  
Balance Control ◽  
Electric Energy ◽  
Equivalent Model ◽  
Stable Operation ◽  
System Control ◽  
Port Access ◽  
Voltage Balance ◽  
Energy Routing

Aiming at the demand for medium- and high-voltage port access capability in energy router, this study proposes a quad-port DC/DC converter topology scheme based on modular multilevel converter (QP-M2DC). Compared with the traditional multiterminal energy routing converter, it has the advantages of high modularity, strong flexibility, and high power density. In addition, for the modular structure on the medium- and high-voltage sides, this study proposes a narrow phase-shift cyclic modulation strategy, which reduces the system need for voltage balance control and simplifies the overall system control. This study comprehensively introduces and analyses the QP-M2DC topology, working principle, high-frequency link equivalent, and power characteristics, then establishes an equivalent model of system control, and proposes a control scheme for a multiterminal energy routing converter. Finally, a simulation model of the system is established through PLECS, and the simulation results show that in such a narrow phase-shift modulation strategy, the proposed topology can have stable operation in a variety of patterns, reduce the capacitance, and achieve better voltage balance at the same time. The experimental results show the converter efficiency of up to 97.8%. It further shows the superiority of the proposed topology structure and the correctness and effectiveness of the proposed control schemes.

scholarly journals Energy Storage System Control for Energy Management in Advanced Aeronautic Applications

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
A. Cavallo ◽  
G. Canciello ◽  
B. Guida
Keyword(s):  
Energy Management ◽  
High Voltage ◽  
Control Strategy ◽  
Storage System ◽  
Electric Energy ◽  
Gain Control ◽  
Energy Storage System ◽  
High Gain ◽  
System Control ◽  
High Level

In this paper an issue related to electric energy management on board an aircraft is considered. A battery pack is connected to a high-voltage bus through a controlled Battery Charge/Discharge Unit (BCDU) that makes the overall behaviour of the battery “intelligent.” Specifically, when the aeronautic generator feeding the high-voltage bus has enough energy the battery is kept under charge, while if more loads are connected to the bus, so that the overload capacity of the generator is exceeded, the battery “helps” the generator by releasing its stored energy. The core of the application is a robust, supervised control strategy for the BCDU that automatically reverts the flow of power in the battery, when needed. Robustness is guaranteed by a low-level high gain control strategy. Switching from full-charge mode (i.e., when the battery absorbs power from the generator) to generator mode (i.e., when the battery pumps energy on the high-voltage bus) is imposed by a high-level supervisor. Different from previous approaches, mathematical proofs of stability are given for the controlled system. A switching implementation using a finite-time convergent controller is also proposed. The effectiveness of the proposed strategy is shown by detailed simulations in Matlab/Stateflow/SimPowerSystem.

MSHE-PWM Control of Modular Multilevel Direct Current Transmission System

2015 ◽  
Vol 9 (1) ◽  
pp. 553-559
Author(s):  
HU Xin-xin ◽  
Chen Chun-lan
Keyword(s):  
Pulse Width Modulation ◽  
Reactive Power ◽  
Balance Control ◽  
Electric Energy ◽  
Access Point ◽  
Experimental Result ◽  
Switching Frequency ◽  
Pwm Control ◽  
Harmonic Elimination

In order to optimize the electric energy quality of HVDC access point, a modular multilevel selective harmonic elimination pulse-width modulation (MSHE-PWM) method is proposed. On the basis of keeping the minimum action frequency of the power device, MSHE-PWM method can meet the requirement for accurately eliminating low-order harmonics in the output PWM waveform. Firstly, establish the basic mathematical model of MMC topology and point out the voltage balance control principle of single modules; then, analyze offline gaining principle and realization way of MSHEPWM switching angle; finally, verify MSHE-PWM control performance on the basis of MMC reactive power compensation experimental prototype. The experimental result shows that the proposed MSHE-PWM method can meet such performance indexes as low switching frequency and no lower-order harmonics, and has verified the feasibility and effectiveness thereof for optimizing the electric energy quality of HVDC access point.

scholarly journals Modeling Stray Capacitances of High-Voltage Capacitive Dividers for Conventional Measurement Setups

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1262
Author(s):  
Alessandro Mingotti ◽  
Federica Costa ◽  
Lorenzo Peretto ◽  
Roberto Tinarelli ◽  
Paolo Mazza
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Equivalent Circuit ◽  
High Voltage ◽  
Equivalent Model ◽  
Simulation Environment ◽  
Element Analysis ◽  
Ratio Error ◽  
Complicated Geometries

Stray capacitances (SCs) are a serious issue in high-voltage (HV) applications. Their presence can alter the circuit or the operation of a device, resulting in wrong or even disastrous consequences. To this purpose, in this work, we describe the modeling of SCs in HV capacitive dividers. Such modeling does not rely on finite element analysis or complicated geometries; instead, it starts from an equivalent circuit of a conventional measurement setup described by the standard IEC 61869-11. Once the equivalent model including the SCs is found, closed expressions of the SCs are derived starting from the ratio error definition. Afterwards, they are validated in a simulation environment by implementing various circuit configurations. The results demonstrate the expressions applicability and effectiveness; hence, thanks to their simplicity, they can be implemented by system operators, researchers, and manufacturers avoiding the use of complicated methods and technologies.

scholarly journals High Power Density, High-Voltage Parallel Resonant Converter Using Parasitic Capacitance on the Secondary Side of a Transformer

Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1736
Author(s):  
Jaean Kwon ◽  
Rae-Young Kim
Keyword(s):  
Power Density ◽  
High Voltage ◽  
Electrostatic Precipitator ◽  
Power Supplies ◽  
Equivalent Model ◽  
Resonant Converter ◽  
High Voltage Power Supply ◽  
Resonant Capacitor ◽  
Parasitic Components ◽  
Secondary Side

High-voltage DC power supplies are used in several applications, including X-ray, plasma, electrostatic precipitator, and capacitor charging. However, such a high-voltage power supply has problems, such as a decrease in reliability, owing to an increase in output ripple voltage, and a decrease in power density, owing to an increase in volume. Therefore, this study proposes a method for improving the power density of a parallel resonant converter using the parasitic capacitor of the secondary side of the transformer. Due to the fact that high-voltage power supplies have many turns on the secondary side, a significant number of parasitic capacitors are generated. In addition, in the case of a parallel resonant converter, because the transformer and the primary resonant capacitor are connected in parallel, the parasitic capacitor component generated on the secondary side of the transformer can be equalized and used. A parallel cap-less resonant converter structure developed using the parasitic components of such transformers is proposed. Primary side and secondary side equivalent model analyses are conducted in order to derive new equations and gain waveforms. Finally, the validity of the proposed structure is verified experimentally.

scholarly journals Electrical properties of a liquid crystal dispersed in an electrospun cellulose acetate network

2018 ◽  
Vol 9 ◽  
pp. 155-163 ◽  
Author(s):  
Doina Manaila Maximean ◽  
Octavian Danila ◽  
Pedro L Almeida ◽  
Constantin Paul Ganea
Keyword(s):  
Liquid Crystal ◽  
Cellulose Acetate ◽  
Indium Tin Oxide ◽  
Electric Energy ◽  
Equivalent Model ◽  
Electrical Characteristics ◽  
Impedance Measurements ◽  
Polymer Dispersed Liquid Crystals ◽  
Polymer Dispersed ◽  
Crystal Composite

Electro-optical devices that work in a similar fashion as PDLCs (polymer-dispersed liquid crystals), produced from cellulose acetate (CA) electrospun fibers deposited onto indium tin oxide coated glass and a nematic liquid crystal (E7), were studied. CA and the CA/liquid crystal composite were characterized by multiple investigation techniques, such as polarized optical microscopy, dielectric spectroscopy and impedance measurements. Dielectric constant and electric energy loss were studied as a function of frequency and temperature. The activation energy was evaluated and the relaxation time was obtained by fitting the spectra of the dielectric loss with the Havriliak–Negami functions. To determine the electrical characteristics of the studied samples, impedance measurements results were treated using the Cole–Cole diagram and the three-element equivalent model.

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