Optimal precalculation of the position-phase current projile for current feeding a 4-phase, 4 kW switched reluctance motor, results in a single input, linear. decoupled output torque controller, which provides low torque ripple. A bicubic spline interpolation was used to model the non-linear experimental data. The algorithm is bused 011 minimizing both the average and peak current hence improves the dynamic performance of the novel six switch, current fed, igbt 4 kW, 40 kHz inverter. Test results by instuntaneous speed measurement over the speed runge 100-300 rpm, ruted torque, open-loop optimizing technique are presented,

Torque ripple reduction of switched reluctance motors by phase current optimal profiling

In this article, a new torque sharing function (TSF) method is proposed for torque ripple reduction in switched reluctance machines (SRMs). The proposed TSF achieves lower current tracking error by establishing a new current reference generation strategy. The phase current reference is first derived from the torque command using offline calculations and also from the phase current response that is obtained from the dynamic model of the SRM. Then, an optimization problem is formulated to shape the current reference for the objective of minimizing the torque ripple and copper losses, while maintaining the required average output torque at the given operating speed. The dynamic simulation of the SRM model is also utilized in the optimization problem. Compared to the existing conventional and optimization-based TSFs, the proposed TSF exhibits lower current tracking error due to the consideration of the current dynamics. Better torque–speed performance with improved average torque and reduced torque ripple is also obtained, especially during commutation. Simulations and experiments under different operating conditions are carried out to verify the proposed TSF method.

A New Torque Sharing Function Method for Switched Reluctance Machines With Lower Current Tracking Error

This paper proposed an optimization algorithm for torque sharing function (TSF) based on numerical iterative algorithm for switched reluctance motor (SRM). This optimization problem takes minimum rms voltage as the minimum optimization objective, current-limiting and bus voltage as the constraint. It gets free from a particular fitting function, making it has advantages of wide universality. Detailed design process of algorithm is illustrated in the paper. The results show that current-limiting is the main constraint at low speed. While at medium and high speeds, bus Voltage is the main limiting factor. The optimized TSF is applied to a 6/4 SRM. Simulations and experiment have been carried out to verify the effectiveness a of the proposed algorithm.

An Offline Iterative Torque Optimization for Extended-Speed Control of Switched Reluctance Motor Drives

Torque ripple is a serious drawback in the operation of a switched reluctance motor which limits its use in high performance applications. Researchers have developed several closed loop control strategies for the reduction of torque ripple in SRM, among which Torque Sharing Function (TSF) based control is a very popular control scheme. While TSF control is effective in reducing the torque ripple, implementation of the same necessitates the usage of two dimensional look-up tables to store the torque characteristics of the motor which are highly non-linear. Further, the modifications proposed in TSF algorithm for achieving secondary control objectives involve numerical optimizations making the control scheme more complex. A simple Current Sharing Function (CSF) based control scheme is proposed in this paper which can effectively reduce the torque ripple in SRM with reduced computational complexity as compared to other instantaneous torque control methods. The theoretical background and closed loop implementation scheme of the proposed method are presented. Further, the efficacy of the proposed control method in reducing the torque ripple is validated through simulation studies.

Current Sharing Function Based Torque Ripple Reduction Strategy For Switched Reluctance Motor Drives

In order to reduce the torque ripple of the switched reluctance machine, a new control strategy, characterized by online correction of the reference phase torque, is proposed based on the torque sharing function. First, the required total torque is distributed to each phase based on the cosine-type torque sharing function, and the real-time phase current is used to predict its maximum and minimum value that the machine can reach at the next control period. Then, the phase torque range can be obtained, which is applied to the online correction of the reference phase torque. The goal of the correction is to make the reference value of the phase torque within the torque range. Finally, the corrected reference torque is converted into reference current for current tracking, and the drive signal for the power converter can be generated. To evaluate the performances of the proposed control method, detailed simulation and experiment are carried out. The results indicate that compared to the traditional torque sharing function method, the proposed method can effectively reduce the torque ripple and enhance the efficiency simultaneously. 

Torque Ripple Reduction of Switched Reluctance Machine With Torque Distribution and Online Correction

Regarding to the past decades, Switched reluctance motor usage in the industry is very limited. Non-linear magnetic function and lack of accurate analytical models are some examples of obstacles on the application development of this motor. In comparison to other motors, discrete oscillations of produced torque and working in magnetic saturation zone have caused considerable mechanical and audio vibrations. One of the torque control methods and mitigation of its oscillation is through using torque sharing functions. Through the method, torques of each phase, respecting of pre-defined function, are controlled so that the produced torques of commutated phases, remain constant and equal to reference torque. In this paper, conventional torque sharing functions are examined and modified considering the motor characteristics and the obtained results using the proposed method are presented.

Torque ripple reduction of Switched reluctance motor using improved torque sharing functions

Start-up and damping of a standing wave thermoacoustic engine: model development and experimental evaluation

Abstract Wall cooling panels are typically a kind of electric arc furnace equipment that has precisely influence on different aspects of the steelmaking process. This investigation employs a CFD method to evaluate the thermal performance of water cooling panels in real operating conditions to validate the numerical method followed by replacing cooling water with Al 2 O 3 /Water nanofluid coolant. The results are revealed that the high rate of receiving heat flux and generated vortexes with low-velocity cores lead to hot spots inducing on bends and elbows. In the operating flow rate, the maximum temperature of the hot-side wall decrease by 14.4% through increasing the nanoparticle concentration up to 5%, where the difference between maximum temperature and average temperature on the hot-side decrease to 12 degrees. According to the results, use of nanofluid coolant is a promising method to fade the hot spots out on the hot-side and gifting a lower and smoother temperature distribution on the panel walls of thereby prolonging the usage period of panels. 

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A. Moradi

Papers

Torque ripple reduction of Switched reluctance motor using improved torque sharing functions

Start-up and damping of a standing wave thermoacoustic engine: model development and experimental evaluation

Numerical investigation of nanofluid heat transfer in the wall cooling panels of an electric arc steelmaking furnace

Supervised Machine Learning with Finite Element Residual Stress Prediction in a Laser Peened (Ti-6al-7nb) Titanium Alloy for Medical Applications