Aliev N.A., Ganiyev S.Y.
INVESTIGATION OF TRANSMISSION OPERATION OF FREQUENCY CONTROLLED ASYNCHRONOUS MOTOR *
Аннотация:
various technical devices are used in all spheres of economy and human activity. All these devices are designed to meet the modern needs of mankind and ultimately serve to purchase a quality product. In order to move the working bodies of these technical devices, such a machine-engine system should be developed so that it is possible to fulfill the requirements of the production process. All this is manifested in the form of electrical transmission. This is the principle of quick adjustment. The frequency and the supply voltage of the motor can be changed independently of each other accordingly, which makes it easier to control the speed of the asynchronous motor in an effective way. general principles of frequency management are explored.
Ключевые слова:
frequency converter, regulation of rotational frequency, electromagnetic torque
DOI 10.24412/2712-8849-2024-271-505-510
This is the principle of quick adjustment. The frequency and the motor supply voltage can be varied independently of each other accordingly, which facilitates the efficient control of the speed of the induction motor. In order for this method to be implemented, the rotating magnetic flux of the stator should be proportional to the frequency 1 of the power source according to the known equation. Therefore, by changing the frequency of 1, it is possible to adjust the rotation frequency of the rotor smoothly and in a wide range. Meanwhile, since the shift S changes very little according to the equation, the losses proportional to the shift decrease accordingly. The rotation frequency of AM is determined by the following expression. From the above, it is clear that for TTAM (speed adjustable asynchronous motor), first of all, a frequency adjustable alternating current source is required. For this purpose, synchronous generators whose speed is regulated are not justified from both technical and economic points of view. It was only after the development of static semiconductors that TT industrial electrical transmissions became possible. The main output coordinate of power transmission is electromagnetic torque. In short, its value depends on both the frequency and the voltage of the alternating current source.
Therefore, due to the presence of two control channels, speed regulation in the TC-AM system is carried out by different laws. If a constant load capacity of the engine is expected, then soon the 1st law of control becomes as follows.
This law was first established by academician M.P. Kostenko.In accordance with expression (1), the power factor and the absolute shift of electric transmission remain practically unchanged in engine control. At the same time, its f.i. does not depend on the speed. This is soon considered the main advantage of management.Depending on the type of load, the voltage and frequency control laws have different forms. For example, at a constant load moment (Ms=const) expression (1) and in the "fan" load. The mechanical characteristics of T-AM which preserves the engine's ability to change load, are given in figure 1. Figure 1. TC-AM transfer in a at a constant moment, at constant power conditions in b, In c, the mechanical characteristics of the fan load are given. Figure 1. TC-AM transfer in a at a constant moment, at constant power conditions in b, In c, the mechanical characteristics of the fan load are given. Thus, in order to implement the principle of frequency control of an asynchronous motor, it is necessary to control the voltage applied to the stator of the motor in accordance with expression (1) and taking into account the type of load, which in turn is related to the change of the feeding frequency. Therefore, static converter devices are used for normal operation of electric transmission, regulation of its parameters and engine speed. All main types of converter devices are applied in the regulated power transmission system, rectifiers – convert alternating current into direct current, inverters - on the contrary, they convert direct current into alternating current.Figure 1 Mechanical characteristics of TC-AM system governed by different laws.The most common TCs are two-step converters. These devices consist of a three-phase rectifier and an autonomous voltage inverter (AGI). At the same time, these devices are widespread in production, despite the fact that the F.I.E. decreases slightly during the processes taking place in them. Unlike autonomous current inverters (ACI), AGIs have a capacitor connected in parallel at the input. Therefore, the connection of this capacitance with semiconductor switches allows obtaining smoothed load voltage curves at the output. A large value of input power factor is ensured when non-controllable switches are applied. Transverse pulse modulation (PMP) is used to adjust the value of the output voltage. EIM is considered a part of transverse impulse adjustment (EIT). The relation of the transverse impulses of the opposite poles along each half-wave of the output voltage is such that the average value of each pair of impulses is equal to the main harmonic value of the output voltage in the middle of the interval in the period of their frequency sequence. The output curve of AGI (single-phase) voltage is shown in figure 2.Figure 2. The shape of the output voltage of a single-phase EIM AGI, U(1)AGI is the fundamental harmonic.The set output voltage is determined by the high harmonic frequency EIM. Modern IGBT type transistors can be used in AGI to cause a slight decrease in F.I.E., but it can raise the frequency up to 4 kHz. Therefore, despite the fact that the high harmonic amplitude of the voltage of the AGI is quite stepped, the current of the active-inductive load practically takes a sinusoidal form.Figure 3. The shape of the output voltage of one phase of the AGI with three-phase.Conclusion. A comparative analysis of the working principles of electric transmissions of the speed-regulated engine is given. It can be concluded that unregulated electric transmissions have low energy indicators. The speed adjustment range is too low. The power factor is small (0.4-0.5). In regulated electric transmissions, the energy indicators are very high, the power factor (0.9), the speed is smoothly regulated and they have a large regulation range. This ultimately allows to increase the productivity of the well.
Номер журнала Вестник науки №2 (71) том 2
Ссылка для цитирования:
Aliev N.A., Ganiyev S.Y. INVESTIGATION OF TRANSMISSION OPERATION OF FREQUENCY CONTROLLED ASYNCHRONOUS MOTOR // Вестник науки №2 (71) том 2. С. 505 - 510. 2024 г. ISSN 2712-8849 // Электронный ресурс: https://www.вестник-науки.рф/article/12902 (дата обращения: 17.05.2024 г.)
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