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Sensorless Control of Double-Sided Linear Switched Reluctance Machines with Eccentricities
Qianlong Wang,Zhengfei Wu,Wei Jiang 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.5
The Double-sided Linear Switched Reluctance Machine (DLSRM) suffers from complex eccentricities in practical operations. A novel sensorless control method for a DLSRM with eccentricities is developed in this paper. The influences of eccentricities on the machine inductance characteristics and the estimated positions in sensorless control systems are discussed. A new position index, which is independent of eccentricities, is proposed according to an analysis of a DLSRM equivalent magnetic circuit. On the basis of this position index, the starting and low-velocity operation of eccentric DLSRMs are achieved. Experimental results obtained in the laboratory validate the proposed method.
Sensorless Control of Double-Sided Linear Switched Reluctance Machines with Eccentricities
Wang, Qianlong,Wu, Zhengfei,Jiang, Wei The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.5
The Double-sided Linear Switched Reluctance Machine (DLSRM) suffers from complex eccentricities in practical operations. A novel sensorless control method for a DLSRM with eccentricities is developed in this paper. The influences of eccentricities on the machine inductance characteristics and the estimated positions in sensorless control systems are discussed. A new position index, which is independent of eccentricities, is proposed according to an analysis of a DLSRM equivalent magnetic circuit. On the basis of this position index, the starting and low-velocity operation of eccentric DLSRMs are achieved. Experimental results obtained in the laboratory validate the proposed method.
Fei Wang,Yiqing Chen,Guotao Han,Qianlong Zhang,Qilin Ma 한국물리학회 2016 Current Applied Physics Vol.16 No.10
The planar heterojunction perovskite solar cells, where the perovskite film is deposited directly onto a flat hole blocking layer, have recently attracted a great deal of attention owing to their high performance and ease of processing. However, the interface and its underlying role in carrier transport/recombination kinetics for such perovskite devices prepared under ambient air is still obscure. Herein, we addressed this issue by a dynamic intensity modulated photovoltage spectroscopy (IMVS) model using a continuity equation. The interface and its role in charge-carrier transport/recombination kinetics have been explored and discussed as an approach to understand the origin of the photovoltaic properties for the devices prepared under ambient air. The experimental IMVS responses were measured and satisfactorily fitted to the analytical results. Compared to the typical IMVS model based on dye-sensitized solar cells (DSSCs), the better IMVS fitting results presented in this study indicated that there was a discrepancy between the planar perovskite devices and those of DSSCs in electron transport/recombination properties, because carrier transfer across the TiO2/liquid electrolyte interface in DSSCs has been modified. That is, the Schottky interface in DSSCs needs to be replaced by the semiconductor heterojunction interface in perovskite solar cells (PSCs). Besides, the interface exhibits a more significant role in determining the carrier transport/recombination process by influencing the boundary conditions in a continuity equation. Furthermore, the intensity modulated photocurrent/photovoltage spectroscopy responses demonstrated that the carrier recombination characteristic is ultimately related with the surface and defect density in the interface. Interfacial modification, such as air-annealing, resulting in crystallographic changes, oxygen passivation, and variation in grain domain size, could suppress carrier recombination and prolong charge lifetime, which can yield more photo-generated electrons to be collected by anode, subsequently resulting in strikingly improving photovoltaic performance of the devices. In short, the dynamic IMVS model would help in elucidating the role of interface and the importance of interfacial modification or even interface design in order to obtain a highly efficient solar cell. The study can not only pave the way to construct the currentvoltage curve using a continuity equation model, but also provide new insights into the performance-improving steps for the PSCs prepared under fully open air conditions, which is of great importance for their future commercialization.
Yang Shude,Sun Yipeng,Jiang Wei,Zhang Jiyong,Wang Qianlong,Tong Xiangqian 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.2
It has been found that both the number of paralleled grid-connected converters and the fi lter inductance value will aff ect the system’s stability in weak grid condition. However, a quantitative study on this eff ect is missing in the current literature. The main contribution of this paper is to quantitatively evaluates the infl uence of the number of paralleled grid-connected converters as well as the inductance value of the L fi lters on the system’s stable region. It is fi rst revealed that, when the same controller design principles are applied for L -type grid-connected converters, the stable region of the paralleled grid-connected converter system is dependent on the ratio between the fi lter inductances and the number of paralleled converters. Specifi - cally, the stable region is proportional to the ratio. Compared to the qualitative analysis in previous work, this fi nding can provide quantitative guidelines on the fi lter inductors or control system design for grid-connected converter applications in weak grid. Finally, experimental tests are carried out using two paralleled grid-connected converters to confi rm the fi ndings.