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Wang F.,Shanghai JiaoTong University | Wang F.,BMW AG | Wang Y.,Shanghai JiaoTong University | Gao Q.,Shanghai JiaoTong University | And 2 more authors.
IEEE Transactions on Power Electronics | Year: 2016

This paper proposes a novel circulating-current control strategy applied in back-to-back parallel three-phase converters with individual dc links for permanent magnet synchronous motor (PMSM) drives. First, the zero-sequence circulating current and the cross current paths in the whole parallel system are analyzed. Then, the models of an n-paralleled subsystem with individual dc links in both the three-phase stationary coordinates and the synchronous rotating coordinates are built up, which explores the fundamental mechanism of circulating current. Based on the analysis, a novel control strategy can suppress the circulating current at the motor side. The control system consists of two main loops in the d-axis, q-axis, and zero-axis, which are defined in this paper as sum control and difference control. The proposed control strategy effectively suppresses the circulating current in both steady-state and transient operations. The zero-sequence circulating current is greatly reduced by the difference control on the zero-axis. In addition, the bandwidth of the controllers is greatly improved, especially when the current-sharing inductance is much smaller than the stator inductance. Finally, with a PMSM load, the simulation and experiment results are presented to verify the theoretical analysis and proposed control strategy. © 1986-2012 IEEE.


Chen X.,Tongji University | Yin J.,Tongji University | Wang W.,Tongji University | Wu L.,Tongji University | Tang F.,Shanghai Mitsubishi Elevator CO.
Journal of Advanced Mechanical Design, Systems and Manufacturing | Year: 2016

Ride comfort and road holding ability of distributed drive electric vehicles are worsened due to large unsprung mass introduced by wheel side drive system. To diminish this large unsprung mass negative effects, three approaches ("Suspension and Reducer Integrated" Close-to-Wheel Drive System, "Dynamic Vibration Absorber" Close-to-Wheel Drive System and in-wheel drive system with "Active and Energy Regenerative Suspension") are introduced. The corresponding dynamics are analyzed and the schemes are provided. Evaluations of suspension performance show the superiorities of these approaches in different magnitude compared with the conventional configuration which is equipped with hub motor and passive suspension. Overall comparisons between three approaches are carried out and the feasibilities are discussed. With proper design according to specific application, these approaches are promising to be applied on various wheel side drive systems. © 2016 The Japan Society of Mechanical Engineers.


Chen Y.-D.,Shanghai Mitsubishi Elevator Co. | Liu Y.-B.,Shanghai Mitsubishi Elevator Co. | Zhu W.-B.,Shanghai Mitsubishi Elevator Co. | Wang S.-L.,Shanghai Mitsubishi Elevator Co.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2010

The performance of matrix converters (MCs) modulated by the conventional space vector indirect modulation (SVIM) method under abnormal input condition will deteriorate. For this phenomenon, an improvement method for the SVIM of MC was proposed. It realizes the improvement of the conventional SVIM by a new correcting factor constructed by a vector method, such that well performance of MCs modulated by the improved SVIM can be obtained under the abnormal input condition. The results of the simulation and the experiment both show the effectiveness of the improvement method. © 2010 Chin. Soc. for Elec. Eng.


Xu B.,Zhejiang University | Cheng M.,Zhejiang University | Yang H.,Zhejiang University | Zhang J.,Zhejiang University | And 2 more authors.
IEEE/ASME Transactions on Mechatronics | Year: 2015

The electrohydraulic flow matching system is one of the most promising fluid power technologies for the improvement of the control performance and system efficiency of mobile machinery. However, pressure impacts and low efficiencies caused by flow excess are significant drawbacks that hinder its development. To solve this problem, this paper proposes a hybrid displacement/pressure control scheme by utilizing a switching rule according to the pressure margin and the candidate Lyapunov function. The mathematical model of an electrohydraulic flow matching system with primary pressure compensators was established, and the energy efficiency performance was analyzed. Experimental tests in single-actuator and dual-actuator systems were carried out on a test rig with a hydraulic excavator. The experimental results indicated that the pump pressure could be reduced when the supplied flow was excessive, and also the system efficiency was improved. The proposed controller is simple and pragmatic so that it can be easily implemented in the current mobile machinery. © 2015 IEEE.


Chen X.,Tongji University | Gu C.,Tongji University | Yin J.,Tongji University | Tang F.,Shanghai Mitsubishi Elevator CO. | Wang X.,Tongji University
IEEE Transportation Electrification Conference and Expo, ITEC Asia-Pacific 2014 - Conference Proceedings | Year: 2014

Featuring compact structure, short transmission chain and high efficiency, the distributed drive electric vehicle has arisen great attention worldwide. In this paper, the research and development status of distributed drive electric vehicle chassis configuration is summarized. Specifically to suppress the negative effects of unsprung mass of the distributed drive electric vehicle, several novel schemes are introduced based on methods of lightweight design, mass transfer, dynamic vibration absorber and active suspension. Combined with some novel technologies, the developing trend of distributed drive electric vehicle chassis is discussed. © 2014 IEEE.


Chen X.,Tongji University | Yin J.,Tongji University | Gu C.,Tongji University | Tang F.,Shanghai Mitsubishi Elevator CO. | Wang X.,Tongji University
IEEE Transportation Electrification Conference and Expo, ITEC Asia-Pacific 2014 - Conference Proceedings | Year: 2014

The unsprung mass of direct wheel drive EV is increased significantly because of the in-wheel motor or motor with reducer. This brings the negative effects of the stability, safety and the ride comfort. In this paper, several schemes of direct wheel drive system for suppressing unsprung mass negative effects were proposed. A typical scheme was modeled and simulated to verify the suppression of unsprung mass negative effects. Then, a specific structural scheme for the single-link independent suspension direct wheel drive system with a dual-stage gearbox was proposed. And a prototype was made based on the research. © 2014 IEEE.


Patent
Shanghai Mitsubishi Elevator Co. | Date: 2016-06-01

This application discloses a safety detection device of passenger conveying equipment, which comprises: one or more kinds of marks provided on any of the low-speed rotary parts, at least one kind of the marks or the combination of various marks being distributed across 360 degrees on a tubular side or an annular bottom of at least one of the low-speed rotary parts for representing different rotation angles of the low-speed rotary parts; at least one optical sensor that is isolated from the low-speed rotary parts where the mark of the rotation angle is located and used for identifying the mark; and a controller connected with the sensor, used for calculating the step movement direction and/or step movement speed of the passenger conveying equipment according to the mark identified by the optical sensor at different times, and stopping movement of the passenger conveying equipment in case of the step inversion or speeding movement. This application covers various kinds of faults, and adopts non-contact optical detection means, thus improving its reliability and movement stability significantly.

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