The basic principle of vector control is to control the excitation current and torque current of the asynchronous motor according to the principle of magnetic field orientation through the measurement and control of the stator current vector of the asynchronous motor, and then achieve the purpose of controlling the torque of the asynchronous motor. Specifically, the stator current vector of the asynchronous motor is decomposed into the current component that generates the magnetic field (excitation current) and the current component that generates torque (torque current), and the amplitude and phase between the two components are controlled separately, that is, the stator current vector is controlled, so this control method is called the vector control method. Vector control methods include vector control mode according to slip frequency, vector control mode without speed sensor, and vector control mode with speed sensor.
The vector control method according to the slip frequency control is also based on the stable control of U/f=, by detecting the actual speed N of the asynchronous motor, the corresponding control frequency F is obtained, and then the stator current vector and the phase between the two components are controlled according to the expected torque, and then the output frequency F of the general-purpose inverter (Variable-frequency Drive, VFD) is controlled. The most important feature of the vector control method according to the slip frequency control is that it can eliminate the fluctuation of torque and current in the dynamic process, and then improve the dynamic function of the general-purpose type. In the early stage, the vector control general-purpose base adopted a vector control method based on the slip frequency control.
Sensorless vector control is based on the theory of field-oriented control. In order to complete the accurate vector control of the magnetic field orientation, it is necessary to install a magnetic flux detector in the asynchronous motor. It is difficult to install a magnetic flux detector in an asynchronous motor. However, it has been found that even if the magnetic flux detector is not directly installed in the asynchronous motor, it is possible to obtain a quantity corresponding to the magnetic flux in the general-purpose type, and then obtain the so-called vector control method without a speed sensor. The basic control thinking is to detect the excitation current (or magnetic flux) and torque current as the basic control variables according to the input motor nameplate parameters according to the certain connection. By controlling the frequency of the voltage on the stator winding of the motor, the excitation current (or magnetic flux) and the command value and the detection value of the torque current are together to output the torque, and then the vector control is completed.
The general-purpose type with vector control can not only match the DC motor in the speed range, but also control the torque generated by the asynchronous motor. Because the vector control method is based on the accurate parameters of the controlled asynchronous motor, some general-purpose motor VFDs need to accurately input the parameters of the asynchronous motor when they are used, and some general-purpose motor VFDs need to use speed sensors and encoders, and use the VFD special motor specified by the inverter manufacturer to control, otherwise it is difficult to achieve the desired control effect. Now, the new vector control general-purpose type has the functions of automatic recognition and self-adaptation of asynchronous motor parameters. The VFD with this function can automatically identify the parameters of the asynchronous motor before it is driven to normal operation, adjust the relevant parameters in the control algorithm according to the recognition effect, and then carry out useful vector control for the general asynchronous motor. In addition to the above-mentioned sensorless vector control and torque vector control, which can improve the torque control function of asynchronous motors, the new technology also includes the adjustment of the control constants of asynchronous motors and adaptive control to match the mechanical system. , and then improve the application function of the asynchronous motor. In order to prevent speed deviations in asynchronous motors and achieve the desired smooth speed in the low-speed range, the use of LSI and dedicated digital automatic voltage conditioning (AVR) control technology has been put into practice with outstanding results.
|
More on that
|
Reynolds inverter power selection
The system power is equal to the product of the power of a general-purpose inverter and the power of the motor. As long as both work efficiently, the system power will be higher. From the perspective of power, when choosing VFD power, you should pay attention to the following points:
VFD ...
|
|
The water pump is controlled by a frequency converter – Reynolds
1. The constant pressure water supply of the inverter increases the comfort of water supply by 3 times
2. Constant water pressure, reducing pipe bursts and leakage by 80%
3. High efficiency and energy saving, power saving effect up to 20%-60% (depending on the actual situation)
4. The use of frequency converters can realize multi-point pressure in different time periods.
|
|
Introduction to soft starters and their relationship with frequency converters - Reynolds
When the high-power motor starts, the current is large, which will cause the grid voltage to be seriously shaken, in order to deal with this problem, the general requirements for speed regulation are not high, and the soft engine can be used to reduce the voltage and start. However, the drop in the starting current when the step-down is started will also make the starting torque drop significantly.
|
|
The cause of damage to the inverter brake unit - Reynolds
The inverter motor is equipped with a mechanical brake, is the inverter motor in the power generation condition when parking? Is the brake unit of the inverter working at the moment? What are the causes of brake unit damage?
Answer: 1. The inverter motor is equipped with a mechanical brake, and when parking...
|
|
Inverter leakage solution - Reynolds
1. The cause of the leakage problem
Some sites use frequency converters to control the motor, which will present the problem of leakage, and the leakage voltage ranges from tens of volts to 200 volts. In view of this problem, the reasons for this shortcoming are theoretically expounded and stated as follows.
Depend on...
|
|
The role of frequency conversion technology in work equipment - Reynolds
Because inverters are widely used, there are many differences in the corresponding types and specifications. We are broadly divided into two categories: voltage and current. The current type of inverter products is characterized by the use of a large inductor as the energy storage link in the middle DC link, and the reactive power will be buffered by this inductor. ...
|
|
The difference between inverter motor and ordinary motor – Reynolds
Inverter motor - used for special occasions with inverter, it is different from the general motor in that a strong cooling fan is added. And the power of the fan comes from the independent power supply, can not be from the main motor out of the line, the effect of the strong cooling fan is to ensure that the motor at low speed...
|
|
The cause of bearing noise in different situations of frequency converters - Reynolds
1. If the bearing is in good continuous rotation condition, it will emit a low whining or humming sound. Sharp hissing, squeaking and other irregular sounds often indicate that the bearing is in a bad continuous rotation condition. The sharp squeaky noise can be due to the formation of an inappropriately smooth ...
|
|
The main failure mode of mechanical parts – Reynolds
The top failure modes of mechanical parts:
Failure: The mechanical part cannot complete its normal function within the planning and booking period and under the regular conditions.
Ways in which mechanical parts fail: overall cracking, plastic deformation, corrosion, abrasion, gluing, and touch exhaustion
General ...
|
|
Reynolds inverter E.oC3 constant speed operation overcurrent fault solution
Reynolds inverter RNB1000 series E.oC3 constant speed operation overcurrent fault solution
Reynolds inverter fault codes:
E.oC3
Reynolds inverter fault phenomenon/type:
Constant speed operation overcurrent
Possible causes of Reynolds inverter failure:
...
|
|
What inverter to choose what occasion - Reynolds
We need to ensure that the capacity of the inverter is matched. First of all, according to the nature of the load, the correct selection of the type of inverter.
When selecting the inverter, the current value of the actual motor should be used as the basis for the selection of the inverter, and the rated power of the motor can only be used as a ...
|
|
Use the right power for the inverter – Reynolds
Low pressure issues
The VFD reports a low voltage glitch when the drive's DC link voltage drops below 62% of the nominal level at the high setting (480 Vac) and 50% of the nominal value at the low setting (400 Vac).
The +10% and -15% voltage tolerances in most manuals are the ones that claim to be ...
|
|
Reynolds JJR5000 Series Soft Starter Manual
Reynolds JJR5000 series all-digital intelligent communication motor soft engine adopts power electronics skills, microprocessor skills and modern control theory skills, and is a new type of engine equipment at the current level. The product can limit the starting current of the asynchronous motor when it starts, and is widely used in electric fans, ...
|
|
Classification of Reynolds inverter types
1. Classified according to the input voltage level
According to the input voltage level, the inverter can be divided into low-voltage inverter and high-voltage inverter, and the low-voltage inverter is common in China with single-phase 220 V inverter, three-phase 220 V inverter, and i-phase 380 V inverter. High-voltage inverters are commonly used in 6 kV, 10 kV transformers.
|
|
Operating procedures for Reynolds frequency converters
Bypass cabinet: The cabinet is equipped with high-voltage inlet and outlet isolation switches QS1 and QS2. Among them, QS1 is a single-pole single-throw variable frequency incoming knife switch, and QS2 is a single-pole double-throw power frequency and variable frequency outgoing knife switch. The bypass cabinet is a high-voltage environment, please investigate the status of the live display and electromagnetic lock to ensure safety before ...
|
|
Inverter installation and heat dissipation treatment - Reynolds
The inverter has power loss during operation and converts it into heat energy, which increases its own temperature. Roughly speaking, the power loss of every 1kVA inverter capacity is about 40W-50W. Therefore, when installing the inverter, it is necessary to consider the heat dissipation of the inverter, and how to run the inverter.
|
|
Reynolds inverter overhaul process
1) Query and query fault phenomena. The fault phenomenon of the inverter is varied, for example, the same type of problem may have different problem phenomena, and different types of problems may have the same kind of problem, which brings difficulties to find the problem. However, the problem phenomenon is the fundamental basis for repairing the inverter ...
|
|
Inverter control loop wiring taboo - Reynolds
1. The wires laid out in the inverter control circuit should be separated from the main circuit cable (power line), so as to avoid the harmonic disturbance components on the side of the main circuit of the inverter from polluting the inverter control circuit;
2. Due to the faulty signal of the inverter and ...
|
|
Reynolds-5G empowers the paper industry to improve quality and efficiency of the industrial IoT control system
From September 23rd to September 25th, 2020, the 2020 China International Paper Technology Exhibition was held in Hall D1 of Suzhou International Expo Center.
|
|
Reynolds drives use the most energy-efficient method
As an electronic electric, the inverter itself also consumes electricity (about 3-5% of the additional power). A 1.5 hp air conditioner consumes 20-30W of electricity, which is equivalent to the length of a lamp. The inverter works under the power frequency and has the function of saving electricity, which is practical.
But the conditions are:
At the top of the list, great success ...
|
|
Contact
working hours
