A Highly Efficient and Reliable Power Scheme Using Improved Push-Pull Forward Converter for Heavy-Duty Train Applications

Author(s):  
Liran Li ◽  
◽  
Zhiwu Huang ◽  
Heng Li ◽  
Xiaohui Qu ◽  
...  

Electronically controlled pneumatic (ECP) brake systems have become popular in heavy-duty train applications because of their advantages, which include shorter stopping distances, improved handling, and less brake-shoe and wheel wear. In ECP brake systems, an improved power supply is required to support efficient and reliable operations. In this paper, we propose a new power converter for ECP brake systems, which is derived from a conventional push-pull converter. As opposed to conventional push-pull converters, we insert a clamping capacitor into the proposed circuit. This clamping capacitor simultaneously enables a greater number of operation modes for the proposed converter and absorbs the voltage spikes in the switch. The proposed converter is more suited for ECP brake applications that require high power, low voltage ripple, and high impedance. We theoretically analyze the proposed converter, and present the design guidelines. Further, we discuss the modeling and control aspects. We demonstrate the operations of the proposed model by performing both simulations and experiments.

Author(s):  
Amey Y. Karnik ◽  
Jing Sun

A control oriented analysis of an anode recirculation system that uses an ejector with a variable throat area is presented for a PEMFC system. Two control issues addressed in this paper are (a) achieving desired recirculated flow to meet humidity control requirements, and (b) regulating anode pressure to protect the polymer membrane from deformation. To meet these objectives, a static feedforward controller using the variable throat area is applied to control the recirculation flow rate, while a proportional-integral controller is designed for anode pressure regulation. A dynamic system model comprising of a nonlinear static characterization of the ejector and dynamic representation of the anode recirculation flow path is developed for controller design and evaluation. Linear analysis is used to derive design guidelines for tuning the feedback controller and to analyze the interactions between the feedback and the feedforward controllers. Our analysis shows that the system characteristics are dependent on the operating condition of throat area of ejector. To meet the control objectives for different operating conditions, a gain scheduling scheme is proposed to adjust the feedback controller parameters and the performance is evaluated through simulations. Results for two representative conditions are included.


Author(s):  
R. Farias Miranda ◽  
D. Ruiz Robles ◽  
V. Venegas Rebollar ◽  
E. L. Moreno Goytia ◽  
N. M. Salgado Herrera ◽  
...  

Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1542
Author(s):  
Hyun-Jun Lee ◽  
Dae-Shik Lee ◽  
Young-Doo Yoon

This paper proposes a new unified power flow controller (UPFC) topology. A single phase of them system with the proposed topology consists of an N:2 transformer with a center tap at the low-voltage side and a power converter module comprising full- and half-bridge converters. A three-phase system can be implemented with three devices. While the conventional UPFC topology uses two three-phase transformers, which are called series and parallel transformers, the proposed topology utilizes three single-phase transformers to implement a three-phase UPFC system. By using an autotransformer structure, the power rating of the transformers and the voltage rating of switches in the power converter module can be significantly decreased. As a result, it is possible to reduce the installation spaces and costs compared with the conventional UPFC topology. In addition, by adopting a full- and half-bridge converter structure, the proposed topology can be easily implemented with conventional power devices and control techniques. The techniques used to control the proposed topology are described in this paper. The results obtained from simulations and experiments verify the effectiveness of the proposed UPFC topology.


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