Aspects Regarding Operation Characteristics of Brush-less Direct Current Motors

Abstract

The researches regarding optimization in the area of electrical machines, include with priority the problem of the energy efficiency, by increasing the efficiency and the power factor. The objectives followed in this paper are the analysis of the operation characteristics, the fabrication and exploitation cost for brushless direct current motors rated at very low power. The utilization of permanent magnets having high specific energy in the construction of these motors influenced the machine performances, the cost and exploitation price. The research carried out aims at reducing the electrical energy consumption in exploitation by optimally dimensioning the permanent magnets. The last part of the paper compares two motors (brushless direct current motor and synchronous motor), both of them having permanent magnets, the same rated data, the same electromagnetic stresses and the same main constructive dimensions. It results that, using the brushless direct current motor instead of the synchronous one, the consumption of active electrical energy is reduced with 11.8%, and the machine weight is reduced with 12.7%.

Particular Transient Regimes of Asynchronous Motors Supplied by PWM Converters

“…This block has been conceived and achieved by the authors of this paper [13]. With the help of the scheme from figure 8 there has been established the time-dependent variation of current of phase A for case when the reference of speed has been modified by jump (f=15 Hz).…”

Modeling and monitoring aspects concerning the vector controlled reluctance synchronous motor drives

“…The necessity to conceive this paper derives from the following obvious conclusions: a) an increasing number of practical applications use, for driving, low power motors of special constructions lately; a special place is occupied by the reluctance synchronous motors [7], [9], [10], [13] etc. ; b) in order to obtain high performances, especially in dynamic regime, the drives having such motors must be controlled in an adequate manner (as known, the vector control responds to this requirement very well [2], [3], [11], [12], etc.…”