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Source publication
Reliability has been a dominant factor in the performance of power converters. In this study, an enhanced k‐out‐of‐n:G model is presented to predict and analyse the reliability of typical asymmetric half‐bridge power converter in switched reluctance motor drive. First, the reliability estimation procedure is introduced including electrothermal mode...
Citations
... There is no winding or permanent magnet on the rotor of the SRM, which increases the reliability of the electrical drive system under high speed and high temperature operating conditions, and economizes the cost of motor manufacturing [11], [12]. Meanwhile, since the unique double-salient pole structure of SRM, when any winding or phase of the motor fails, the stable operation of the SRM drive system can be guaranteed, which provides a favorable advantage for the wide application of the SRM drive system [13]- [15]. At present, one of the most concern in SRM drive system is how to optimize the dynamic quality of speed regulation, especially in star-up stage. ...
... The algorithm selects the appropriate proportional coefficient by judging the size of the rotational speed error signal e, and decides whether to introduce the feedback compensation coefficient γ. The control law of the VPDPI algorithm is shown in Eq. (13). ...
This paper develops a novel switching variable proportional desaturation proportional integral (SVPDPI) regulator for speed control of switched reluctance motor (SRM) drive system. Firstly, the idea of desaturation is adopted in the SRM drive system in order to eliminate the integral saturation phenomenon of traditional proportional integral (PI) regulator. Secondly, the variable proportional desaturation PI (VPDPI) regulator is proposed to enhance the response speed of SRM drive system by introducing the concept of variable proportion. In addition, in order to improve the smoothness of the SRM start-up speed, a switching speed regulator is further designed based on the VPDPI regulator. Finally, the principle of error threshold segmentation is introduced into SVPDPI regulator, whose control performance is compared with among other three regulators under rated speed, various speeds and load-torque conditions. Meanwhile, the dynamic performance, steady performance and start-up performance are comprehensively analyzed. The simulation experiment results commendably indicate that the proposed SVPDPI regulator is superior in tracking performance, anti-disturbance performance and speed range.
... Within this context, it is fundamental to define a methodology to predict the lifetime of a capacitor from the current load profile it delivers. A way to quantify the reliability is through the mean time to failure ratio [26]- [28]. Although it is based on the part count method, it can also use information of the application environment. ...
Switched Reluctance Machines (SRM) are considered promising rare-earth free candidates for the next generation electrified vehicles. One of the main drawback of this technology is the need of a large DC-link capacitor to balance the energy transferred back and forth between the DC source and the SRM. There are interesting novel modulations to reduce the current of the DC bus, focused on the capacitor size and cost reduction but leaving aside the thermal analysis and lifetime improvements. Carrying out the required dynamic multi-physics simulations for that purpose becomes highly time consuming and complex, especially when standardized or real driving conditions are needed to be taken into account. This article proposes a simulation methodology, simple to implement and with a relatively low computational cost, to estimate the lifetime of an automotive DC-link capacitor, with the current load it delivers as the starting point. The presented methodology has also been used to validate a novel SRM modulation technique and to compare it, in terms of reliability, with the conventional torque sharing function.
Purpose
Quantitative reliability analysis can effectively identify the time the driving system needs to be maintained. Then, the potential safety problems can be found, and some catastrophic failures can be effectively prevented. Therefore, this paper aims to evaluate the reliability of the switched reluctance generator (SRG) driving system.
Design/methodology/approach
In this paper, a method considering different thermal stresses and fault tolerance capacity is proposed to analyze the reliability of an SRG. A full-bridge power converter (FBPC) instead of the asymmetric half-bridge power converter (AHBPC) is adopted to drive the SRG system. First, the primary fault modes of the SRG system are introduced, and a fault criterion is proposed to determine whether the system fails. Second, the thermal circuit model of the converter is established to quickly and accurately obtain the junction temperature of the devices. At last, the Markov models of different levels are established to evaluate the reliability of the system.
Findings
The results show that the two-level Markov model is the most suitable when compared to the static model and the one-level Markov model.
Originality/value
The driving system of SRG will be more reliable after the reliability of the system is evaluated by the Markov model. At the same time, an FBPC is adopted to drive the SRG. The FBPCs have the advantages of fewer switching devices, higher integration and lower cost. The proposed driving strategy of the FBPC avoids the current reversal and the generation of dead zone time, which has the advantage of reliable operation. In addition, a precise thermal circuit model of the FBPC is proposed, and the junction temperature of each device can be obtained, respectively.
