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1

A control strategy of a permanent magnet synchronous motor for an electric vehicle

Xie Jianxin, Liu Zimeng

Journal of Theoretical and Applied Mechanics

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2022

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Vol. 60 nr 4

673--685

EN

The traditional modulation method of the inverter in a permanent magnet synchronous mo- tor (PMSM) is lengthy and computationally intensive. Based on this, a simplified sinusoidal pulse width modulation method is proposed. In this method, voltage space vectors in each sector are synthesized, and the sector in which the synthesized vector is located is determined by the rotation angle of the resultant vector, and then the acting time of the basic vector is calculated by the voltage difference of the phase voltage. The problem of trigonometric functions and coordinate conversion is not involved in the whole calculation process, the calculation model is simple, and it is easy to realize digitization. Mathematical modeling is carried out by using the simulation software Matlab, and the correctness of the calculation method after optimization is verified, which provides an idea for the later research of the inverter modulation method.

2

Theoretical determination of voltage arise in machining of gray cast irons

Yardimeden A., Inan A., Aksoy M.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 23, nr 1

79-82

EN

Purpose: Machining conditions should be well determined in order to increase production speed and minimize machining cost. However, it is difficult to produce all information for optimum machining conditions. Therefore it is generally accepted provide the most influential factors for determination of optimum machining conditions. The optimum machining conditions would provide longer tool life and better surface finish quality. Design/methodology/approach: Taylor mentioned a relative between cutting speed and tool life and developed model from consecutive experimental studies completed under invariable machining conditions. Recently the factorial regression analysis has been extensively applied for providing optimum machining conditions for expected tool life and surface roughness. In the present study, voltage differences between workpiece and cutting tool were also taken into consideration for theoretical determination of machining conditions. The results of experimental study carried out for machining of gray cast irons (at different chemical compositions) were modeled by using regression analysis method. Findings: The influence of cutting speed, feed rate, diameter and depth of cut on the voltage difference were investigated. Consequently theoretical values obtained from the equation were similar to the experimental values. Practical implications: The results of experimental study carried out for machining of gray cast irons (at different chemical compositions) were modeled by using regression analysis method. Originality/value: In the present study, a mathematical model was improved using regression analysis method of potential differences between workpiece and cutting tool and, machining on the lathe which is made different chemical compositions of gray cast iron.

3

Impacts of the structure and processing conditions on the voltage arise in machining of gray cast irons

Yardimeden A., Inan A., Aksoy M.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 25, nr 2

81-84

EN

Purpose: Machining is one of the most widely used manufacturing processes. The machining of gray cast iron is important because of wide application of these materials in various industries. The machinability studies have been carried out for these materials and it was reported that the amount of graphite in cast irons was one of the influential factor in tool wear during machining. This study is aimed to provide new approach to examine tool life by considering voltage arise during machining of gray cast irons. Design/methodology/approach: The experimental study carried out to measure voltage values during various machining conditions such as cutting speeds, feed rates and depth of cut. Chemical compositions of the four different gray cast irons were machined and the experimental results were compared to the machining of brass and steel. The selected machining conditions were 0.16, 0.32 and 0.48 mm feed rates, 0.5, 1 and 1.5 mm depths of cut and 125, 250 and 355 rpm spindle speeds, respectively. Findings: It was observed that the voltage difference was detected during the machining of cast iron specimens. This was due to increase of graphite particles within total intersections. This would lead to conclusion that high graphite particles would increase voltage and this would provide information about tool wear. Research limitations/implications: Because of being cheap, the usage of cast iron with lamella graphite particles in specific electric circuits to be used in industrial applications need to be further investigated. Also whether or not the cost iron with lamella graphite particles can be used as voltage storage under intensive stress needs to be investigated. Originality/value: Impacts of the structure and processing conditions on the voltage arise in machining of gray cast irons.

4

Partial discharge analyses ‒ a comparison of different parameters used

Benzerouk D., Patsch R., Menzel J.

Prace Naukowe Instytutu Podstaw Elektrotechniki i Elektrotechnologii Politechniki Wrocławskiej. Konferencje

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2004

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Vol. 40, nr 15

46-50

EN

In the past many approaches have been made to use partial discharge signals to monitor and characterize degradation processes in electric equipment. For the on-line monitoring of large machines or transformers or periodic off-line inspections in many cases only the change of the phase angle distributions of the occurrence of discharges is taken as an indicator for ageing processes in the insulating system. This is sufficient as an indication for the need of a more detailed examination, but often even with off-line experiments the actual change in the defect and especially its relevance for the service life remains unclear. A more detailed insight into the physics of the local degradation processes and their relevance for the ageing process of the equipment can be gained in most cases only with measurements with a continuously increased voltage load and the evaluation of the data via Pulse Sequence Analysis. The paper will discuss and compare different methods to analyze partial discharge data, starting with 'simple' frequency distributions of different parameters of the externally applied voltage load derived from the data set as a whole. As the main point sequence correlated data such as time differences between consecutive discharges will be discussed. It will be shown that in dependence on the type of defect the significance of different parameters is different.