Hong Guo, Shuai Yang, Shaolin Zhang and Zebin Zhang
The purpose of this paper is to study the influence of lubricant temperature-viscosity on the performance for a hydrodynamic journal floating ring bearing (FRB), including…
Abstract
Purpose
The purpose of this paper is to study the influence of lubricant temperature-viscosity on the performance for a hydrodynamic journal floating ring bearing (FRB), including ring-journal speed ratio and stability.
Design/methodology/approach
The finite difference method was used to solve computational models of Reynolds equation, energy equation and temperature–viscosity equation. Dynamic coefficients were obtained based on the floating ring balance. The dynamic model of journal and floating ring was established to deduce the stability criterion of single mass symmetrical rigid FRB rotor system by the Routh–Hurwitz method. The outlet temperature and ring-journal speed ratio under different journal speeds were compared to experimental data.
Findings
The temperature–viscosity effect reduces the ring-journal speed ratio and stability of rotor system. According to theoretical and experimental results, the outlet temperature rises and ring-journal ratio drops when the journal speed rises.
Originality/value
The temperature–viscosity effect is combined with dynamic characteristics to analyze the stability of the rotor system and lubrication mechanism for an FRB. Influence of temperature–viscosity on the ring-journal ratio and multi-stable regions of system are studied.
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Ziyi Liu, Zebin Wu and Jianglin Gu
During the cooperation process between prefabricated building construction enterprises (PBCEs) and Internet platforms (IPs), the sentiments of both parties influence their…
Abstract
Purpose
During the cooperation process between prefabricated building construction enterprises (PBCEs) and Internet platforms (IPs), the sentiments of both parties influence their behavioral strategies. They are the key to improving the informatization and operational efficiency of the prefabricated building industry chain (PBIC).
Design/methodology/approach
This paper introduces mental accounting theory and rank-dependent expected utility theory to construct the MA-RDEU game model, exploring the evolutionary mechanism between sentiment and behavioral strategies of PBCEs and IPs.
Findings
The study indicates that (1) a mixed strategy equilibrium can be achieved when both parties have no sentiments. (2) PBCEs and IPs are more likely to achieve an optimal equilibrium for cooperation if the latter is optimistic. In contrast, pessimism may lead both parties to prioritize self-interest when only one party has a sentiment. (3) The combined impact of sentiments and behavioral strategies on decision-making is significant: the influence of sentiments from PBCEs or IPs on the optimal strategy for achieving cooperation is contingent upon the behavioral strategies of the other party; different behavioral strategies of IPs or PBCEs can have varying effects on sentiments when both parties have sentiments. (4) The influence of external factors on the sentiments and behavior strategies of PBCEs and IPs is apparent. PBCEs and IPs should concurrently consider the combined influence of external factors and sentiments to contribute to the realization of cooperation between the two parties. Additionally, government supervision is an effective means to restrain “free-riding” behavior.
Originality/value
Finally, based on the above conclusions, the paper proposes measures to improve the construction of service-oriented IPs and establish a mechanism for monitoring and adjusting risk sentiments. Meanwhile, this paper also indicates that under the combined effect of the government, PBCEs and IPs, the influence of external factors on sentiments can be maintained within a controllable scope and the risks of uncertainty can be mitigated.
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Zebin Yang, Xi Chen, Xiaodong Sun, Chunfeng Bao and Jiang Lu
The purpose of this paper is to handle the problem of the radial disturbance caused by rotor mass unbalance and load change in a bearingless induction motor (BIM).
Abstract
Purpose
The purpose of this paper is to handle the problem of the radial disturbance caused by rotor mass unbalance and load change in a bearingless induction motor (BIM).
Design/methodology/approach
The active disturbance rejection controller (ADRC) is used to replace the traditional PI controller, and a cubic interpolation method is used to fit the nonlinear function of ADRC, so as to improve the control performance. Meanwhile, a disturbance observer is applied to the suspension system, and the observed disturbance acceleration is compensated to the suspension system in the form of current; thus, the suppression of the rotor radial disturbance is realized.
Findings
The proposed method can effectively suppress the radial disturbance of the rotor, meliorate the suspension performance of the motor and enhance the anti-interference ability of the system. Besides, it has excellent dynamic and static performance.
Originality/value
A radial disturbance control strategy of the BIM based on improved ADRC is proposed is to suppress the radial disturbance of the rotor. The improved ADRC is to enhance the control performance of the system, and the disturbance observer is designed to observe and compensate the disturbance.
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Jiajie Wu, Zebin Yang, Xiaodong Sun and Ding Wang
The purpose of the control method proposed in this paper is to address the problem of the poor anti-interference of the suspension winding current in the traditional bearingless…
Abstract
Purpose
The purpose of the control method proposed in this paper is to address the problem of the poor anti-interference of the suspension winding current in the traditional bearingless induction motor (BL-IM) direct suspension force control process.
Design/methodology/approach
A model predictive direct suspension force control of a BL-IM based on sliding mode observer is proposed in this paper. The model predictive control (MPC) is introduced to the traditional direct suspension force control to improve the anti-interference of the suspension current. A sliding mode flux linkage observer is designed and applied to the MPC system, which reduces the error of the parameter observation and improves the robustness of the system. The strategy is designed and implemented in the MATLAB/Simulink and the two-level AC speed regulation platform.
Findings
The simulation and experimental results show that the performance of the BL-IM under the control method proposed in this paper is better than that under the traditional direct suspension force control, and the suspension performance of the motor and the anti-interference of the control system are improved.
Originality/value
This study helps to improve the suspension performance of the motor and the anti-interference of the control system.
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Although the differential roles of political and business ties are recognized in the literature, the interplay between political and business ties remains unclear. This study aims…
Abstract
Purpose
Although the differential roles of political and business ties are recognized in the literature, the interplay between political and business ties remains unclear. This study aims to explore how political ties affect the formation of business ties with unfamiliar partners by analyzing how a buyer’s political ties affect the market-based selection of suppliers, an important channel through which the buyer forms business ties with unfamiliar suppliers.
Design/methodology/approach
A survey of 204 Chinese manufacturing firms was conducted to elucidate the relationship between political ties and the market-based selection of suppliers.
Findings
The findings suggest that buyers with strong political ties are more likely to engage in the market-based selection of suppliers; this positive relationship is diminished when social control is preferred over contractual control in the buyer’s supplier governance and is enhanced when technological uncertainty is high.
Originality/value
First, this study sheds light on the interplay between political and business ties by revealing how the buyer’s political ties affect the formation of business ties with unfamiliar suppliers, as represented by the market-based selection of suppliers. Second, it uncovers the boundary conditions of the effect of political ties by revealing the moderating effect of social control preference and technological uncertainty. Third, it extends the interorganizational governance structure literature from its focus on the complement-substitute debate on social control and contractual control to examine the contingent effect of a hybrid governance structure.
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Xiaodong Sun, Jiangling Wu, Shaohua Wang, Kaikai Diao and Zebin Yang
The torque ripple and fault-tolerant capability are the two main problems for the switched reluctance motors (SRMs) in applications. The purpose of this paper, therefore, is to…
Abstract
Purpose
The torque ripple and fault-tolerant capability are the two main problems for the switched reluctance motors (SRMs) in applications. The purpose of this paper, therefore, is to propose a novel 16/10 segmented SRM (SSRM) to reduce the torque ripple and improve the fault-tolerant capability in this work.
Design/methodology/approach
The stator of the proposed SSRM is composed of exciting and auxiliary stator poles, while the rotor consists of a series of discrete segments. The fault-tolerant and torque ripple characteristics of the proposed SSRM are studied by the finite element analysis (FEA) method. Meanwhile, the characteristics of the SSRM are compared with those of a conventional SRM with 8/6 stator/rotor poles. Finally, FEA and experimental results are provided to validate the static and dynamic characteristics of the proposed SSRM.
Findings
It is found that the proposed novel 16/10 SSRM for the application in the belt-driven starter generator (BSG) possesses these functions: less mutual inductance and high fault-tolerant capability. It is also found that the proposed SSRM provides lower torque ripple and higher output torque. Finally, the experimental results validate that the proposed SSRM runs with lower torque ripple, better output torque and fault-tolerant characteristics, making it an ideal candidate for the BSG and similar systems.
Originality/value
This paper presents the analysis of torque ripple and fault-tolerant capability for a 16/10 segmented switched reluctance motor in hybrid electric vehicles. Using FEA simulation and building a test bench to verify the proposed SSRM’s superiority in both torque ripple and fault-tolerant capability.
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Xiaodong Sun, Zhuicai Zhou, Long Chen, Zebin Yang and Shouyi Han
Inductance, torque and iron loss are the key parameters of switched reluctance motors for belt-driven starter generators. This paper aims to present the analysis of a segmented…
Abstract
Purpose
Inductance, torque and iron loss are the key parameters of switched reluctance motors for belt-driven starter generators. This paper aims to present the analysis of a segmented rotor switched reluctance motor (SSRM) with three types of winding connections for hybrid electric vehicle applications by using a two-dimensional finite element method.
Design/methodology/approach
The rotor of the studied SSRM consists of a series of discrete segments, while the stator is made up of exciting and auxiliary teeth. First, the concept and structures of the different winding connections are introduced. Then, the magnetic flux path of the three types of winding connections for the SSRM is described. Second, the magnetic flux distributions in the three parts, i.e. the stator yoke, the stator tooth and the rotor segment, are described in detail to calculate the iron losses. Third, three SSRMs with the different winding arrangements are analyzed and compared to evaluate the distinct features of the studied SSRM. The analysis and comparison mainly include self-inductances, mutual inductances, phase currents, output torque and iron loss.
Findings
It is found that the self-inductances of the three types of winding connections are almost equal, and only the SSRM1 has a positive mutual inductance. In addition, the current waveforms of SSRM1 and SSRM2 are regular. However, it is irregular in SSRM3. It is shown that SSRM1 has better characteristics, such as higher output torque, high power density, lower torque ripple and iron loss.
Originality/value
This paper proposes and analyzes three novel winding connections for the SSRM to provide guidance for enhancing the output torque and reducing the iron loss to achieve high efficiency.