Control of the Operating Mode of Electric Motors
The control of the operating mode of electric motors of alternating current is based on frequency control techniques. This involves changing the direction of the magnetic flux within the stator and rotor, as well as adjusting parameters such as:
- the frequency of current and voltage;
- the angular difference between phases;
- the amplitude of current and voltage.
Frequency Converter
The conversion of these parameters occurs in a special device called a frequency converter. The structure of this device includes inverter current blocks and rectifier blocks. The operation of these main blocks is controlled by a number of elements and auxiliary circuits. Necessary information, for instance, from a control panel, sensors, or other converters, is sent to the digital inputs of the converter.
Regulating the output voltage parameters is possible due to the auxiliary frequency blocks of the converter, which include various protection circuits, an embedded clock, or microprocessor devices. This allows for control and management of the output voltage in both automatic and manual modes.
Automatic Accounting and Parameter Preservation
There is also the possibility of maintaining automatic accounting and preservation of changes in output voltage parameters. Since the output voltage from the converter is supplied to the motor windings, this in turn allows influencing the operating modes of the motor, such as:
- torque;
- shaft rotational speed;
- analog parameters.
Advantages of Frequency Control
Among the numerous advantages of the established frequency control technology for electric motors are the following:
- significant reduction in electricity costs, and in some cases energy recovery;
- control of technological process parameters (temperature, pressure, humidity, etc.);
- reduction in the likelihood of failures or accidents;
- high accuracy of mechanism operation;
- decreased maintenance and repair costs;
- reduction of planned downtimes or preventive works;
- streamlining management of the entire system.
Impact on Technological Systems
The integration of a frequency converter significantly reduces the mutual influence of power supply and electrical drive circuits. This eliminates the possibility of disruptions in the operation of neighboring consumers.
The use of converters also contributes to high automation of the entire system, reducing the impact of the human factor on the functionality of technological equipment. This ultimately leads to a reduction in personnel costs and often to a decrease in the presence of people in hazardous areas.
Thus, the advantages associated with the use of frequency converters make this technology increasingly popular in various enterprises and organizations.