Inverter is a high-tech product, mainly composed of power electronic equipment and microelectronic equipment. The three-phase communication grid is connected to the input of the frequency converter. The input end of the inverter is a rectifier circuit, and the output end is a frequency conversion circuit. As a result, the voltages and currents on the input and output sides include abundant harmonics, which will cause waveform distortion in the grid; At the same time, whether the grid voltage is symmetrical and balanced, the size of the transformer capacity and whether the nonlinear equipment is connected to the distribution bus will also affect the normal operation of the frequency converter.
The current inverter has a DSP chip or a computer chip, completes the control, and drives the control of the inverter main circuit of the inverter due to the computer chip of the smaller voltage and current, under the high operating speed, it is easy to be disturbed by some external electrical disturbance. Therefore, in order to complete the power supply and drive safe and reliable operation, it is necessary to take measures to suppress the interference between the two.
The rectifier circuit and inverter circuit of the inverter are composed of nonlinear equipment. The circuit structure will cause the voltage and current waveforms of the grid to be distorted. The three-phase communication voltage UR, US, UT is changed to DC through the three-phase bridge rectifier circuit, and the DC voltage does not change at all after being filtered by electrolytic capacitors. The diode used in the rectifier circuit is a nonlinear device. The rectified output voltage is charged to the filter capacitor. The charge current waveform depends on the difference between the rectifier voltage and the capacitor voltage.
When the inverter is operating at different frequencies and currents, the input current waveform is also different. Figure 10-6 shows the input current waveform of a 55kW inverter driving a cage asynchronous motor with a load of 10Hz, 20Hz, and 50Hz. It can be seen that as the frequency and current of the motor are added, the input current changes from intermittent to continuous, and the waveform distortion of the current becomes smaller and smaller. Many harmonic current weights will be obtained by mathematical Fourier series decomposition of these waveforms.
The experiment also proves that when the inverter is running, a certain gap source voltage waveform and outstanding will be formed due to the commutation effect of the rectifier diode.
In summary, when the inverter is running, the voltage and current waveforms of the grid will be distorted. In order to generalize the effect of this distortion on the system, the inductive voltage distortion rate d can be calculated by the following formula
What is the impact of grid quality on the life of the inverter
In the workshop, the drive will be able to be used in different loads above, and the impact of different loads on the inverter itself is not the same.
Under shock loads such as welding machines, electric arc furnaces, rolling mills, etc., voltage flicker often occurs. At this moment, the harmonics generated by the inverter have a very serious pollution to the quality of the power grid, and also have considerable harm to the equipment itself. At worst, it cannot be connected to normal operation, and at worst, the input circuit of the equipment is damaged. This will severely affect the service life of the product.
1. In the case of impact load, such as electric welding machine, electric arc furnace, steel mill, etc. It is advocated that users add reactive power static compensation equipment to improve the power factor and quality of the power grid.
2. The concentration rectifier introduced by the inverter concentration workshop and the common bus of DC power supply. The 12-pulse rectifier mode is recommended. Small harmonics, energy power, especially suitable for frequent starting, braking, motor are in the case of motor operation and power generation operation advantages.
3. A passive LC filter is installed on the input side of the converter to reduce the input harmonics, improve the power factor, have high reliability and good effect.
4. The input side of the inverter is installed on the source PFC equipment, which has the best effect but high cost.
|
More on that
|
Delta's C2000 inverter has evolved completely
For those who are familiar with Delta's automation, they know that Delta's inverters have two main series: "M300" and "C2000".
"Compact Inverter M300 Series": This series has been introduced many times before, including MS300 (standard general-purpose type), MH300 (high power ...
|
|
Rated current design of inverter leakage circuit breaker - Delta
1. Install AC reactor and DC reactor. When the capacity of the inverter is greater than 500kva in the distribution transformer, and the transformer capacity is more than 10 times the capacity of the inverter, an AC reactor is installed on the input side of the inverter. And when the output voltage of the distribution transformer is unbalanced and uneven in three phases ...
|
|
How Delta's touch screen works
Delta's touch screen consists of a contact detection component and a touch screen controller.
The contact detection component is installed in front of the display screen to detect the user's contact orientation and is sent back to the touch screen controller; And Delta's touch screen controller's ...
|
|
The cause of short circuit in power transformer - Delta
Power transformers are used very frequently in daily livelihoods, in order to ensure the normal use of electricity, the safety and stability of the power transformer is the key point, once the transformer has a problem of prevention, it is necessary to quickly find out the cause and deal with it, take the transformer short circuit as an example, the damage caused by the insufficient treatment is ...
|
|
The basic methods and steps of inverter debugging - Delta inverter
1. No-load energizing test of inverter
1. Ground the grounding terminal of the inverter.
2. Connect the power input terminal of the inverter to the power supply through the leakage maintenance switch.
3. Check whether the factory display window of the inverter is normal, if it is incorrect, it should be reset, no ...
|
|
Characteristics of common models of Delta inverters
Delta MS300 Inverter Series: Delta's compact standard vector-operated inverter MS300 combines the advantages of miniaturization, high functionality, high trust, and simple installation, transforming every investment in industrial resources into abundant results. Optimized structure with lock-free screw terminals to plan the supply of bento ...
|
|
The principle of Delta's inverter inverter
As far as I know, since the advent of active induction motors, there has been a variable frequency operation in the way of communicating generators. Change the rotational speed of the generator, and change its output frequency. Before the advent of high-speed transistors, this was one of the main ways to change the speed of the motor, but due to the decrease in the speed of the generator ...
|
|
Delta's active front-end and inverter's coordination
The popularity of frequency converters has brought significant energy savings to industrial applications. However, the high-frequency switching signal generated by the inverter is easy to cause electromagnetic interference and affect the power quality. Especially in industries with large loads such as lifting and elevators, it is becoming more and more obvious.
...
|
|
Method for measuring temperature rise during reducer operation - Delta
The thermometer method and resistance method can be used to measure the temperature rise of each part of the reducer.
1) Thermometer method: This is the easiest way to measure the temperature directly, and it is commonly measured by an alcohol thermometer. When measuring, the thermometer can be placed close to the ...
|
|
Delta inverter parameter replication error solved
1. SE2 parameter imitation error
Problem Description:
Keypad Imitation Function Fault Correction 2
Solution:
1. The Keypad imitation action is completed, and the inverter parameters are written into error
2. SE1 Parameter Imitation ...
|
|
Replaced by discontinued models of Delta inverters
Delta's new generation of compact and efficient vector-controlled inverter MH300, adhering to the good driving function of Delta's inverter, has six advantages: compact size, flexible application, stable system, reliable quality, and easy installation.
|
|
Delta's inverter speed regulation application site
Inverter is a kind of speed regulating device, where to use the motor speed regulation, especially asynchronous motor speed regulation, will use the inverter, now mainly in industrial equipment has been used on a large scale, because the motor is the heart of the industry, and the three-phase asynchronous motor occupies the vast majority of the share, ...
|
|
The principle structure of low-voltage circuit breaker - Delta
Low-voltage circuit breakers, commonly known as active air switches, are one of the primary electrical switches in low-voltage distribution networks. It can not only turn on and off normal load current, motor operation current and overload current, but also turn on and off short circuit current.
It is mainly used as a low-voltage distribution line or a switch cabinet that is not often operated ( ...
|
|
Precautions for Delta's DPA pressure sensor
1. When the device is installed, leave the place with high voltage and strong high-frequency noise to prevent disturbance. Prevent use in places where the following conditions occur:
(a) Excessive dust and corrosive gases; (b) high humidity and very high radiation; （c） ...
|
|
The energy-saving principle of inverter - Delta
In order to ensure the reliability of production, all kinds of production machinery are designed with power drive, and there is a certain surplus when designing and matching power drive. When the motor cannot operate at full load, in addition to reaching the power drive requirements, the residual torque increases ...
|
|
The inverter has a built-in PLC function - Delta
PLC progressive scanning standard work preparation.
Abundant programming language: instruction statements; ladder diagram; SFC。
Abundant instruction statements: 45 instruction varieties, including 28 root instructions and 17 usage instructions.
350 step law capacity.
uS-level root directives ...
|
|
Delta launched the MZM, a high-power positional drive system
Driven by consumption promotion and product diversification, the manufacturing industry's demand for automation and intelligent promotion in production and processing is also increasing. In the production process, the processing of "large and heavy" items is often difficult to control accurately, and the deviation of orientation is not as easy as that of "small" items. To this end ...
|
|
Delta's LOYTECIoT building management platform helps Yili Group reduce costs
Intelligent houses are selected with fully automatic automatic control systems to consider the diverse requirements of community owners, managers and users in housing management methods. In the new project of Yili Group's Food Science R&D Trend Management Center, under the framework of opening to the outside world, Damei has made use of Loytec ...
|
|
Inverter optocoupler device type - Delta
1. One is a triode type photocoupler, such as PC816, PC817, 4N35, etc., which is commonly used in the output voltage sampling and error voltage amplification circuit of the switching power supply circuit, and is also used in the digital signal input loop of the inverter control terminal. The structure is the simplest, and the input side consists of a light-emitting two...
|
|
The role and application of Delta's thermostats
Delta's thermostat is a commonly used temperature control device, which can adjust the temperature according to the user's needs, and then achieve the intention of saving energy. The effect and use of Delta thermostats are also very widespread, so let's introduce the effects and uses of Delta thermostats.
...
|
|
Contact
working hours
