Topology (electrical circuits)

About: Topology (electrical circuits) is a research topic. Over the lifetime, 33316 publications have been published within this topic receiving 397651 citations. The topic is also known as: topology.

LC-RNN: A deep learning model for traffic speed prediction

Abstract: Traffic speed prediction is known as an important but challenging problem. In this paper, we propose a novel model, called LC-RNN, to achieve more accurate traffic speed prediction than existing solutions. It takes advantage of both RNN and CNN models by a rational integration of them, so as to learn more meaningful time-series patterns that can adapt to the traffic dynamics of surrounding areas. Furthermore, since traffic evolution is restricted by the underlying road network, a network embedded convolution structure is proposed to capture topology aware features. The fusion with other information, including periodicity and context factors, is also considered to further improve accuracy. Extensive experiments on two real datasets demonstrate that our proposed LC-RNN outperforms seven well-known existing methods.

Multiport Converters Based on Integration of Full-Bridge and Bidirectional DC–DC Topologies for Renewable Generation Systems

Abstract: A systematic method for deriving multiport converters (MPCs) from the full bridge (FB) converter (FBC) and bidirectional dc-dc converters (BDCs) is proposed in this paper through sharing the parasitized switching legs by the BDCs and the FBC. By employing the proposed method, families of FB and BDC-based MPCs (FB-BDC-MPCs), including some existing ones, are developed for renewable generation systems with the merits of simple topology, reduced devices, and single-stage power conversion. Voltage regulations between any two ports can be achieved by employing pulsewidth modulation and phase-angle-shift control scheme. Furthermore, zero-voltage switching for all the switches can be realized in the proposed FB-BDC-MPCs. A typical four-port converter developed by the proposed method, named buck/boost four-port converter (BB-FPC), is analyzed in detail as an example in terms of operation principles, design considerations, and control strategy. Experiments have been carried out on a 500-W prototype of BB-FPC, which demonstrate the feasibility and effectiveness of the proposed topology derivation method.

A 13-Levels Module (K-Type) With Two DC Sources for Multilevel Inverters

Abstract: This paper presents a new reconfiguration module for asymmetrical multilevel inverters in which the capacitors are used as the dc links to create the levels for staircase waveforms. This configuration of the multilevel converter makes a reduction in dc sources. On the other hand, it is possible to generate 13 levels with lower dc sources. The proposed module of the multilevel inverter generates 13 levels with two unequal dc sources (2 V DC and 1 V DC). It also involves two chargeable capacitors and 14 semiconductor switches. The capacitors are self-charging without any extra circuit. The lower number of components makes it desirable to be used in wide range of applications. The module is schematized as two back-to-back T-type inverters and some other switches around it. Also, it can be connected as a cascade modular which leads to a modular topology with more voltage levels at higher voltages. The proposed module makes the inherent creation of the negative voltage levels without any additional circuit (such as H-bridge circuit). Nearest level control switching modulation scheme is applied to achieve high-quality sinusoidal output voltage. Simulations are executed in MATLAB/Simulink and a prototype is implemented in the power electronics laboratory in which the simulation and experimental results show a good performance.

A Five-Level Inverter Topology with Single-DC Supply by Cascading a Flying Capacitor Inverter and an H-Bridge

Abstract: In this paper, a new three-phase, five-level inverter topology with a single-dc source is presented. The proposed topology is obtained by cascading a three-level flying capacitor inverter with a flying H-bridge power cell in each phase. This topology has redundant switching states for generating different pole voltages. By selecting appropriate switching states, the capacitor voltages can be balanced instantaneously (as compared to the fundamental) in any direction of the current, irrespective of the load power factor. Another important feature of this topology is that if any H-bridge fails, it can be bypassed and the configuration can still operate as a three-level inverter at its full power rating. This feature improves the reliability of the circuit. A 3-kW induction motor is run with the proposed topology for the full modulation range. The effectiveness of the capacitor balancing algorithm is tested for the full range of speed and during the sudden acceleration of the motor.

A PWM LLC Type Resonant Converter Adapted to Wide Output Range in PEV Charging Applications

Abstract: In conventional LLC-based plug-in electric vehicle (PEV) onboard chargers, the battery pack voltage varies in a wide range with the change of state of charge. This makes it difficult to optimally design the pulse frequency modulated LLC resonant converter. Besides, the voltage regulation of the LLC converter is highly dependent on the load conditions. In this paper, a modified pulse width modulated (PWM) LLC type resonant topology (PWM-LLC) is proposed and investigated in PEV charging applications. The switching frequency of the primary LLC network is constant and equal to the resonant frequency. The voltage regulation is achieved by modulating the duty cycle of the secondary side auxiliary mosfet . Compared with the conventional LLC topology, the proposed topology shrinks the magnetic component size and achieves a wide and fixed voltage gain range independent of load conditions. Meanwhile, zero-voltage-switching and zero-current-switching are realized among all MOSFETs and diodes, respectively. A 100-kHz, 1-kW converter prototype, generating 250–420 V output from the 390-V dc link, is designed and tested to verify the proof of concept. The prototype demonstrates 96.7% peak efficiency and robust performance over wide voltage and load ranges.