Large screen introduces you to the five basic functions of Delta inverter
< p="">Delta inverter full name change Governor, is one of the three-phase motor drive control devices, in industrial automation, and its effect is insignificant position, indispensable. The development of domestic inverter technology has been around for 20 years. I have experienced the borrowing, breeding, germination, growth, prosperous period, and experienced many things during the period. Many people have spared no effort and effort to leave in the historical process of China's automation industry. A page with a strong ink color. Compared with the large machinery industry and automation, the inverter industry is still a small village, but it is also surging and spectacular. In this article, the wide-screen combined with many years of experience, I want to clarify the basic functions of the inverter, inaccuracies, welcome readers to communicate with me.
1, Soft starter has a soft start function, which is not necessary today, but it was very exciting twenty years ago, this is also the inverter One of the auxiliary basic functions. At the beginning of the inverter, the inverter was designed for the commonly used three-phase asynchronous squirrel cage motor. We know that the speed formula of three-phase asynchronous motor is n=60f(1-s)/p. It is completely convenient and reliable to change the input frequency of the motor and then change the speed of the motor. The instantaneous current of the motor directly starts is 6~8 times of normal and stable operation, the step-down starting is 4~5 times, and the frequency conversion speed regulation will not exceed 1.5 times of the rated current of the inverter, whether it is impact on the power grid or equipment adaptability. The benefits are very prominent. 2, stepless speed regulation
stepless speed regulation, is the levelless stepless speed regulation, from zero speed starting to high speed, and from high speed to zero speed, in one go, speed The curve is continuous, smooth and stable. As shown in Figure 1, it greatly adapts to the load inertia, improves the adaptability of multiple mechanical devices, improves production efficiency, greatly reduces mechanical friction, vibration and noise, and prolongs the Equipment life and reduced maintenance costs. The output frequency of ordinary inverters is around 0.00Hz~400.00Hz, the frequency resolution is all at 0.01Hz, some reach 650.00Hz, the output of high frequency inverter can reach 5000Hz, and it has completely covered all ranges of industrial speed regulation. With the advent of core components such as transistors and microprocessor chips, the company has made a major breakthrough in stepless speed regulation technology. The birth of the frequency converter is the result of meeting the needs of industrial automation and the development of several related industries.
(a) Linear acceleration and deceleration (b) s-curve acceleration and deceleration Figure 1 Inverter output frequency curve Today, the price of the inverter has been reduced enough, the market coverage is wide enough, the manufacturers are more unprecedented, and the user's understanding is also deep enough. Standing in the development process of the entire industrial automation, it is gratifying! The following figure shows the frequency-time curve of the inverter: <3> Energy saving function of the inverter, which was originally an unexpected gain in the application of the inverter, and today, it has been widely used. Application and various industrial and civil production life, especially when the frequency converter is used for square torque load, such as fan, fan, pump, propeller load, which is determined by such load torque curve, as shown in Figure 2 -a shown. At low speeds, the flow torque is low due to the low flow rate of the fluid. As the motor speed increases, the flow rate increases, the load torque and power are also increased, the load torque TL and the power PL Representation: T0, where P0 is the torque loss and power loss on the motor shaft, respectively; KT, PT - the torque constant of the quadratic law load, respectively Power constant.
a) Fan blade b )Mechanical characteristics c) Power characteristics Figure 2 Secondary law load and its characteristics
But the energy-saving application of the frequency converter exists Many misunderstandings, some literature claims that the frequency converter is a power-saving control product, giving the impression that as long as the inverter can save power. In fact, the reason why the inverter can save power is because it can regulate the motor. If the inverter is a power-saving control product, then all the speed control equipment can also be said to be a power-saving control product. The inverter is only slightly higher in efficiency and power factor than other speed control devices. Furthermore, as long as the valve is used to control the flow rate, and it is not full-load operation, it can be operated in a variable speed operation. Compared with the DC speed control system, the DC motor is more efficient than the AC motor and has a high power factor. The digital DC converter is as efficient as the inverter, and even the digital DC converter is more efficient than the inverter. Slightly higher. Therefore, it is claimed that the use of AC asynchronous motors and frequency converters is more energy efficient than the use of DC motors and DC converters. Theoretically and practically, this is not true. 4, Multi-protection
We know that in the actual operation of the equipment, there are often many factors leading to various faults and equipment damage, if intelligent detection, automatic alarm and protection, It will be very necessary, such as under voltage, over voltage, lightning strike, overload, load stall, over temperature, communication fault, electromagnetic interference, power phase loss, motor phase loss, load short circuit, ground short circuit, etc. It is fatal, and once it appears, the consequences are unimaginable. In the development process of the inverter, firstly, due to the consideration of the internal safety of the inverter itself, multiple detection and protection have been added. For example, the allowable current of the inverter inverter module generally does not exceed 2 times of the rated value. The electrolytic capacitor allows The temperature is 85 °C, electromagnetic compatibility design, etc., plus the detection and feedback on the load side (such as motor temperature detection and protection, instantaneous power failure without stopping, etc.), making today's inverter highly intelligent, not only can be protected Its own safe and normal use also greatly protects the safe operation of the front and rear equipment. In addition, today's good inverters have basically passed international certifications or indicators, such as CE, UL, RoHS, etc., can be exported to the outside, inverter manufacturers, also provide all-weather, no geographical differences on the scene Service and user guidance to provide customers with quality assurance and solve their worries. 5, Automation
The control functions of today's inverters are very complete, and can be well matched with other control devices and instruments to achieve centralized real-time monitoring and control of systematic networking, such as with DCS , PLC, sensor, HMI, CNC, host computer, servo drive, etc., greatly improve the automation of the production line, saving manpower and material resources, improving efficiency and reducing costs. For example, the inverter can have multiple frequency setting modes, such as digital setting, potentiometer, external analog quantity (0~10V, 4~20mA), multi-speed, PID, etc., which can be used for various controllers and feedback signals. The frequency command, remote/local control switching, facilitates the user's various control needs, and some companies have successively launched a variety of industry special machines, personalized development for some sub-sector users, integrated development, saving users The problem of troublesome system compatibility in the selection process saves costs. In short, the function and function of the inverter are very perfect and mature today. It is an indispensable member of the industrial automation product family. It has important milestone significance and is also a follow-up high-end technology application and product. The basis of development, perhaps the birth of the inverter, officially opened the prelude to the rapid development of China's automation industry! We have reason to believe that in the future China will have more and better enterprises and products to compete on this battlefield without smoke, but in any case, this is good news for users, it is worthy of our common expectation and continuity. Work hard, tomorrow will be better!