Motion control has obvious period characteristics, it is a variety of high-tech generalization, used to push industrial automation, office automation and home automation to a higher stage. At present, motion control is mainly composed of three parts: Variable-frequency Drive (VFD), motor and controller.
1. VFD local
At the heart of the VFD are the power electronics and the way they operate.
1) Power electronic equipmentPower electronic equipment is the equipment that plays the effect of on-off in the circuit and completes various converters, VFD is the installation of this converter, so it is unfolded with the development of inverter equipment, and the quality of inverter equipment depends on its on-off ability, and accepts the on-off current and rated voltage; In the on-off process, the size of the loss, such as saturation, voltage drop and switching loss, determines the efficiency and volume of the VFD. Switching losses are related to the switching frequency; The switching frequency is related to noise, and is related to the output voltage and current waveform. That is to say, power electronic equipment should be deployed in the direction of high voltage, high current, high switching frequency and small conduction voltage drop. The thyristor is a semi-control device, which belongs to the first generation of products, but the modulation frequency is low, the control is messy, the efficiency is low, the capacity is large, the voltage is high, and the history is long.
The application of GTO thyristors and BJTs, whether assembled DC choppers or assembled VFDs, has a monopoly in the application of GTO thyristors in electric locomotives. This is also a serious scientific research topic that China organized to tackle during the Eighth Five-Year Plan period. However, the use of GTO thyristor VFD for other central is controversial, because the turn-off current gain of GTO thyristor is too small, the overcurrent protection ratio is difficult, and the modulation frequency is low. DC choppers and PWMVFDs assembled with BJT are very popular, but the output voltage does not exceed 460V and the capacity does not exceed 400kW. BJT is a current drive, with high power consumption, low modulation frequency, and high noise, which is not as simple and reliable as the voltage drive of MOSFET. However, the latter has a smaller capacity and a lower output voltage, and there are not many competitive products in the market.
In motion control, the new generation of power electronics are IGBT and MCT: the former is MOS-driven BJT, which has the advantage that the capacity and voltage exceed BJT, and there is a tendency to replace it; The latter MOS drives thyristors and theoretically has the advantages of both. These two new equipment have sophisticated products, IGBT has been developed to the fourth generation, and now foreign countries are transferring the consumption process of microelectronics to power electronics, so the production of application-specific integrated circuits (). The intelligent equipment that combines the drive circuit and the protection circuit of the IGBT is called IPM, and the IPM that combines the switching power supply, so that the VFD is more reliable, and it has become the leading product of speed regulation in the past, which will replace DC speed regulation, and the 21st century will be a period of communication speed regulation.
2) Control methodVFD adopts different control methods, with different speed conditioning functions, characteristics and uses. The control method is roughly divided into open-loop and closed-loop control. Open-loop control includes U/f (voltage and frequency) proportional control; The closed loop includes slip frequency manipulation and various vector manipulations. From the perspective of pre-development history, it is also from an open-loop to a closed-loop. The general vector control is comparable to the armature current control of a DC motor. Now the communication motor parameters can directly stop the direct torque control, which is convenient and accurate, and the control accuracy is high.
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The distance between the Reynolds frequency converter and the motor determines the cable and wiring method
1. The interval between the inverter and the motor should be as short as possible. This reduces the cable's capacitance to ground and reduces the source of disturbance.
2. The control cable is shielded cable, the power cable is shielded cable or from the inverter to the motor.
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Introduction to the braking mode of Reynolds inverter
1. Energy consumption braking: The energy consumption braking method uses the braking resistance set in the DC circuit to absorb the regenerative electric energy of the motor through the chopper and braking resistor, so as to realize the rapid braking of the inverter.
2. Feedback braking: feedback system ...
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The inverter cannot adjust the frequency solution - Reynolds
1. The acceleration moment is too short.
Theoretically, the longer the acceleration time, the stronger the load lifting capacity. If the acceleration time is set too short, some VFDs will show an overcurrent or overload, overtemperature alarm, while others will not, and will only be stuck in a certain frequency band.
2.The V/F ratio is too large
Some of this ...
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Application misunderstandings and drawbacks of inverter and countermeasures - Reynolds
Misunderstanding: connect electromagnetic switches and electromagnetic contactors in the output circuit of the inverter
In actual use, some occasions require the use of contactors for frequency converter switching: such as when the frequency conversion is faulty, switch to the power frequency operation, or when the one-to-two method is adopted, a motor is faulty, and the variable frequency is used.
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The reason why the inverter controls the motor – Reynolds
Q1: Why should I use VFD to control the motor?
When it comes to this issue, let's take a brief look at these two devices. The motor is an inductive load that hinders the change of current, and when it is started, a large change in current is generated. VFD, which is actually made up of a rectifier inverter circuit, ...
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Indicator of Reynolds inverter cabinet wiring
Voltage level: The voltage level should match the voltage level of the power supply and motor to ensure electrical safety and normal operation of the equipment.
Current level: The current level should match the rated current of the motor to ensure electrical safety and normal operation of the equipment.
Cable Specification: Cable ...
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The basic principle of vector control – Reynolds frequency converters
The fundamental 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 to achieve the purpose of controlling the torque of the asynchronous motor. Specifically, it is to ...
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Reynolds inverter code function description
F09 second acceleration time 0.10 - 999.9sec; 5.0sec； △ The first acceleration and deceleration parameters and the second acceleration and deceleration parameters are switched by terminal X3 (see F55);
F10 second deceleration time 0.10 - 999.9sec; 5.0sec； △ The first acceleration and deceleration parameters and the second acceleration and deceleration parameters ...
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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 ...
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Lightning protection measures for Reynolds frequency converters
The lightning protection measures of the inverter equipment are another important peripheral measure to ensure the safe operation of the inverter, especially in the area where lightning is active or in the lively season, this problem is particularly important.
Today's inverter products are generally equipped with mines.
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Protection feature of overcurrent trip - Renol
1. Maintenance objectives of overcurrent
In the frequency conversion speed regulation system, there are two devices: the frequency converter and the motor. The degree of tolerance to overcurrent is not the same. The planners of the production machinery decide on the capacity of the motor based on the principle of heat. That is, as long as the electricity ...
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The factor that causes the breakdown of the inverter – Reynolds
1. Overpressure leads to brake pipe breakdown.
The so-called overvoltage of the inverter refers to the fact that the inverter voltage formed due to various reasons exceeds the additional voltage, which is concentrated in the DC voltage of the inverter DC bus.
The overvoltage alarm generally appears at the time of shutdown, and its main ...
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The cause of the heating of the inverter of the special machine
1. Problems of the inverter and the motor itself;
After the motor has been used for a long time, it cannot be ruled out that the insulation function is not good, or the bearing is stuck, and it may show a large current and heat. The coupling between the motor and the load may also be worn, or the motor is unbalanced in three phases, and the fixtures of the motor are loose.
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The difference between inverter motor and ordinary motor - Reynolds
1. The heat dissipation system is different: Generally, the cooling fan in the fan is in the same line as the fan movement, while the two are separated in the inverter motor. Therefore, when the frequency conversion of the fan is too low, it may burn out due to overheating.
2. Frequency conversion ...
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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.
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Interpretation of Reynolds inverter models
Take the RNB2000 series inverter as an example.
The model number of the RNB2000 series 37kW inverter is: RNB2037-U
RN: on behalf of Reynolds;
B: low-voltage frequency conversion governor;
2: 2000 series;
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Parameter setting of acceleration and deceleration time of Reynolds universal inverter
The acceleration time of the Reynolds inverter is the time required for the output frequency to rise from 0 to the high frequency, and the deceleration time is the time required to decrease from the high frequency to 0. Generally, the frequency converter uses the frequency setting signal to rise and fall to confirm the acceleration and deceleration time. The rise of the frequency setting must be limited when the motor accelerates.
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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. ...
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Centrifugal fan inverter selection method - Renol
1. See if it is energy-saving.
When selecting equipment products, many business managers will take into account the energy-saving embodiment, which is due to the excellent energy-saving embodiment of the product, which can save a lot of money and resources.
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Features of the unit tandem inverter - Reynolds
(1) The multi-pronged PWM control method is selected, and the output voltage waveform is close to the sine wave.
(2) The rectifier circuit is multiplied, the number of pulses is as high as 36, the power factor is high, and the input harmonic is small.
(3) Modular design, compact structure ...
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