CC BY
3УДК 621.314 Rahimli I.N., Ganiyeva N.A., Mehraliyev T.S.
Rahimli I.N.
associate professor Azerbaijan State Oil and Industry University (Baku, Azerbaijan)
Ganiyeva N.A.
laboratory assistant Azerbaijan State Oil and Industry University (Baku, Azerbaijan)
Mehraliyev T.S.
master
Azerbaijan State Oil and Industry University (Baku, Azerbaijan)
COMMUTATION METHODS IN CONTACTLESS DC MOTORS
Аннотация: the article discusses various commutation methods in contactless DC motors, which are an important component of modern electromechanical systems. Their operating principles are discussed, as well as the advantages and disadvantages of each method. Methods such as the use of Hall sensors, optical and inductive sensors, and encoders are analyzed in detail. Each of these methods offers unique features to provide accurate and stable motor control under a variety of operating conditions.
Ключевые слова: contactless DC motors, commutation, efficiency, reliability, sensors.
Conventional DC motors have a valuable quality - the ability to widely and smoothly regulate the rotation speed. However, they have a significant drawback due to the brush-collector unit. It is quite natural that the idea arose to create motors that have the advantages of DC motors and are free from their disadvantages. Such motors
are called non-contact DC motors. Contactless DC motors represent a key technology in modern electromechanics, delivering high efficiency, reliability and durability. They have found wide application in various fields including industry, automation, robotics and electronics.
Contactless DC motors consist of three elements:
1) a contactless motor with an m-phase winding on the stator and an excited rotor, usually in the form of a permanent magnet,
2) a rotor position sensor, made in the same housing with the motor and designed to generate control signals for timing and the sequence of current switching in the stator windings,
3) a commutator, usually a transistor, which, based on signals from the rotor position sensor, switches currents in the stator windings.
Figure 1 shows a simplified schematic diagram of a brushless DC motor.
Figure 1. Simplified schematic diagram of a contactless DC motor.
One of the important aspects of the operation of non-contact DC motors is the commutation process, which ensures that current is directed correctly through the motor windings, allowing it to rotate smoothly and stably. Challenges associated with commutation in DC motors include selecting an appropriate commutation method, ensuring accuracy and stability under varying operating conditions, and managing
electromagnetic interference. Various research and development methods are used to solve these problems [1-5].
Commutation methods in contactless DC motors are a variety of approaches to switch the phases of motor windings without the use of corner contacts. Let's look at the basic commutation methods in more detail:
1) Using Hall sensors:
Hall sensors are used to determine the rotor position and phase switching time. They detect changes in the magnetic field and transmit information to the motor controller, which then controls the phase switching.
- Advantages: Easy to install, low cost, high accuracy.
- Disadvantages: Limited rotation speed, possibility of electromagnetic interference.
2) Using optical sensors:
Optical sensors determine the position of the rotor using a light signal. They work based on changes in light output as the rotor rotates.
- Advantages: High accuracy, no mechanical wear.
- Disadvantages: Sensitivity to contamination, high cost.
3) Use of inductive sensors:
Inductive sensors respond to changes in the magnetic field created by a rotating rotor. They detect changes in inductance and transmit information about the position of the rotor.
- Advantages: High reliability, resistance to vibration and temperature changes.
- Disadvantages: High cost, difficult to install.
4) Using encoders:
The encoders generate a sequence of pulses that allows the angular position of the rotor to be determined. They provide high accuracy and feedback on rotor position.
- Advantages: High accuracy, feedback capability.
- Disadvantages: High cost, additional equipment required.
These commutation methods play a critical role in the efficiency and reliability of contactless DC motors. The choice of the optimal method depends on the
requirements of the specific application, taking into account factors such as rotation speed, positioning accuracy and cost [6-10].
Conclusion. Understanding each commutation method allows engineers to select the most appropriate solution for a specific application based on speed, accuracy, reliability and cost requirements. Moreover, continued advances in technology in this area may lead to new commutation methods that improve the efficiency and performance of contactless DC motors. Thus, further research and innovation in switching techniques plays an important role in the development of modern electromechanics and provides improvements in the performance and reliability of electromechanical systems.
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