CC BY
4ЭНЕРГЕТИКА И АЛЬТЕРНАТИВНАЯ ЭНЕРГЕТИКА
(ENERGY & ALTERNATIVE ENERGY)
УДК 621
Mammadov N.S.
laboratory assistant of the Department of Electromechanics Azerbaijan State Oil and Industry University (Baku, Azerbaijan)
Nasibov Q.A.
master of the Department of Electromechanics Azerbaijan State Oil and Industry University (Baku, Azerbaijan)
RESEARCH OF A SYNCHRONIZED ASYNCHRONOUS MACHINE
Abstract: recently, interest in synchronized asynchronous machines has been growing more and more. A synchronized asynchronous machine is a conventional wound-rotor induction machine, two or three phase windings of which are supplied with direct current. The article presents a diagram of a synchronized asynchronous machine. The article also discusses the analysis of the magnetic field, and more specifically, the magnetic motive force (mfs) of the rotor winding of a synchronized machine. To analyze this curve, the m.f.s. using the graphic method. According to the research, the main advantages and disadvantages of a synchronized asynchronous machine have been identified.
Keywords: synchronized asynchronous machine, research, winding, vibration damping, phase zone.
This machine should be called synchronous-asynchronous, since it can work as both an asynchronous and a synchronous machine. High-power synchronized asynchronous machines are used by well-known electrical companies in electric drives with difficult starting conditions, as accelerating motors for large units of pumped storage power plants, etc. They are also used in draw works drives and in mechanisms
that require angular position control. A particularly important role is played by the use of a synchronized asynchronous machine in wind power plants [1]. Of the synchronization schemes of an asynchronous machine known to us, the scheme, which is shown in Fig. 1, is of the greatest interest.
Fig.1. Scheme synchronized asynchronous machine
In this scheme, with a standard design of a phase rotor, the principle of longitudinal-transverse excitation is implemented. As is known, a synchronous machine with longitudinal-transverse excitation has significantly improved characteristics compared to conventional machines [2]. This applies to damping oscillations and increasing the stability of work under sharply variable and pulsating loads, typical for drilling mechanisms, wind turbines, etc. This scheme is the only way to implement a longitudinally-transversely excited synchronous machine based on a standard machine. Therefore, a comprehensive study and analysis of this scheme is an urgent task [3].
Let us consider the analysis of the magnetic field, and more specifically, the magnetic motive force (mfs) of the rotor winding of a synchronized machine when it is powered according to the scheme in Fig.1. To analyze this curve, the m.f.s. a graphical method is required. The essence of this method is as follows. A graph of the distribution of the coil sides of the rotor winding in phase zones is drawn (see Fig. 2,
where the cross section of the coils that belong to different phases are shown by different figures). The values and directions of the currents in the coil sides are given inside the indicated figures (dots and crosses, and their number corresponds to the magnitude of the current, namely: in the absence, the current is zero, the presence of one, for example, a dot corresponds to the current I = 0.5 r.u., the presence of two - I = 1.0 r.u.) [4].
I r » -t •/ ' r r ' -t -r ' / m t te ¥ A t s t ' *
<fQ AA CÎb ©lb AA 0~b ©<5) ¿f& DO A A tfb
a)
I tfi -VI •/ -tu t til -t)I ./ -til ft
 * A M С * # Ж Л щ с д
(jfè Д^ 00 А'А ЕГи Q~à ¿ГД В H (5® ДА QQ ФАДЕИЭФФАДаиОФАДВафФАДИ Q©
b)
c)
Fig.2. Plots of distribution m.d.s. rotor of a synchronized induction machine
Curves m.f.s. for a three-phase two-layer rotor winding with the following data:
z = 24; 2p = 4; q= 2 and v = 1T are presented in fig. 2, a, b, c. Options a, b and c in
y 6
this figure correspond to the states of the circuit in Fig. 1 with the given functioning. Similar curves of m.f.s. were built for windings with a diametrical pitch, used as rotary windings of high power asynchronous machines, as well as for windings with a fractional number of slots per pole and phase.
During this study, it was also found that the excitation circuit of a synchronized asynchronous machine according to Fig. 1 is universal, from which, as special cases, the known circuits for supplying the phases of the rotor winding with direct current are obtained [5]. The conducted research revealed the following:
1) for integer q, all half-waves of the m.f.s. have the same shape and the abscissa axis is the axis of symmetry;
2) there is a change in the shape of the m.f.s. curve. during the transition of the circuit from one state to another, however, this change is insignificant;
3) as q increases, the m.f.s. becomes smoother, which indicates a decrease in higher harmonics in it;
4) for fractional q, the shape of the m.f.s. curve is not the same. north and south poles and, therefore, along with odd higher harmonics, in the m.f.s. there will also be even harmonics.
5) the last circumstance, along with the question of the influence of the shape of the current curve in the phases (the degree of smoothing of the rectified current), requires additional consideration.
REFERENCES:
1. Mustafaev R.I., Abdulkadyrov A.I. The use of a synchronized asynchronous generator in a wind power plant.//Problems of Energy, 2003, No. 1, pp. 28-32.
2. Nijat, Mammadov. Selection of the type of electric generators for a wind electric installation. Universum journal, pp.65-67 №9(102)
3. September,2022.:DOI: 10.32743/UniTech.2022.102.9.14234 https://7universum.com/pdf/tech/9( 102)/9( 102_5).pdf
4. Abdulkadyrov A.I. The problem of damping oscillations of synchronous machines with sharply variable load and ways to solve it // Uchenye zapiski ADNA. 1997. No. 1. S. 59-64.
5. Abdulkadyrov A.I. A new principle of synchronization of an asynchronous motor // Elektrotekhnika. 1998. No. 4. S. 17-20.
6. Kostenko M.P., Piotrovsky L.M. Electric cars. T.2. Moscow, Energy, 1969, pp. 174-190.
