Most popular unveiling the mystery of variable fre

2022-08-15
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After the 1990s, China's air conditioners have entered a period of great development, and the production and sales volume has increased year by year. The varieties of demand have changed from the previous window type to the split type. For softer materials, a larger speed is selected for experimental changes, and the demand for cabinets is growing rapidly. The design of air conditioner integrates advanced technologies in related fields, such as frequency conversion technology is a very important part. The unique performance of variable frequency air conditioning can fully meet people's requirements for improving the quality of life. In order to let consumers have a better and more comprehensive understanding of variable frequency air conditioning and uncover the mystery of variable frequency air conditioning, the following is a specific introduction to the necessity and current situation of the application of variable frequency technology, the development direction of variable frequency air conditioning and how to rationally understand multi-function

first, the necessity and current situation of the application of frequency conversion technology

the development direction of household appliances in the early 21st century will be energy conservation, environmental protection, intelligence, informatization and personalization. Among them, energy conservation has always been the focus of household appliances research, because the fossil fuels used for thermal power generation are not inexhaustible. In order to achieve sustainable energy development, since 1995, China has successively begun to organize the revision of the first batch of energy efficiency standards and the formulation of some new energy efficiency standards for household appliances and lighting products. So far, several standards such as GB12021.3 "limited value of energy efficiency and evaluation value of energy conservation of room air conditioners" have been completed. After the implementation of the new standard, the energy efficiency of air conditioners will be increased by 10%, which is expected to significantly reduce CO2 emissions and coal consumption. The application of frequency conversion technology is a necessary way to realize the technological innovation of household appliances. Frequency conversion technology will play an increasingly important role in the future development of household appliances. The research on frequency conversion technology in China began in 1994, first in Chunlan and Haier, and later in Midea, Hisense, Kelon and Gree. All major companies attach great importance to the research and development of frequency conversion technology. While digesting and absorbing the imported technology, they actively develop and develop domestic variable-frequency air conditioners

due to the relatively advanced frequency conversion technology adopted by the variable frequency air conditioner, the voltage fluctuation during startup is small, and it can be started under low voltage and low temperature conditions. In this way, it can improve the problem that the air conditioner is difficult to start in some areas due to unstable voltage or low temperature in winter. Because the stepless speed change of the compressor is realized, the variable frequency air conditioner can meet the cooling and heating demand of a larger area, that is, the cooling or heating capacity is much larger than that of ordinary air conditioners. For example, in Chunlan variable frequency air conditioner, its maximum refrigeration and heating capacity can reach 130% - 140% of the rated refrigeration capacity. The purpose of air conditioning is to create an artificial climate place. It mainly regulates and controls the air temperature, humidity, air velocity and air cleanliness of the environmental space. When the room temperature and the set temperature are large, the variable frequency air conditioner can automatically operate at the maximum capacity, quickly reduce the temperature difference, and make people feel comfortable and comfortable in a short time without being prone to "air conditioning disease"

in addition, we know that heat pump air conditioners are difficult to warm in winter. The emergence and application of frequency conversion technology is one of the more effective ways to improve the poor heating performance of heat pump air conditioners. Experiments show that the heating capacity of variable frequency air conditioners will decline with the decrease of outdoor temperature, but this range is much smaller after all. When the outdoor temperature is -7 ℃, the heating output capacity of the variable frequency air conditioner can still output about 80% of the rated value compared with the heating capacity measured at -7 ℃ specified in the national standard. Obviously, it is much larger than about 45% of the heating capacity of ordinary heat pump air conditioners under the same outdoor temperature. Of course, when the variable frequency air conditioner adopts the variable frequency control elements and variable frequency compressor, if the electronic expansion valve is used to throttle synchronously, the advantages of the low-temperature heating performance of the variable frequency air conditioner in winter can be more fully and perfectly reflected. In addition, the downward fluctuation of room temperature during defrosting can also be avoided and solved in variable frequency air conditioners. The variable frequency air conditioner with electronic expansion valve throttling can defrost the outdoor unit without stopping the heating of the indoor unit

it is said that the variable frequency air conditioner can operate continuously at a low speed, so it can achieve the purpose of saving power. This seems to be reasonable, because when it operates at low speed and small cooling capacity, the heat exchange area of the condenser has a large surplus. Sufficient heat exchange conditions reduce the condensation pressure, reduce the power consumption of the compressor, and thus improve the refrigeration coefficient cor value. However, on the other hand, the heat exchange area of the evaporator also has a large surplus. Excessive heat exchange increases the superheat of refrigerant vapor, and then reduces the volumetric efficiency of the compressor. The positive and negative offset of the two makes it impossible for low-speed operation to improve efficiency

the real power saving of variable frequency air conditioner lies in its continuous operation, which saves the starting current when the constant speed air conditioner is frequently started. However, this is a difficult indicator to assess, and only like the large central variable frequency air conditioner, which operates continuously 24 hours a day, can this advantage be reflected. However, Chinese people can't do this by using the operation mode of air conditioning, which is often turned on and off at home; It turns on when it is hot and turns off when it is cold, which greatly reduces the advantages of continuous operation. Although the starting current of the air conditioner is large, the time is very short, and the cumulative power consumption will not be too large. Moreover, we can also reasonably match the capacity of the air conditioner and reasonably select the air volume to reduce the number of start and stop of the constant speed air conditioner as much as possible. Therefore, whether the variable frequency air conditioner can save electricity must be analyzed in detail. To publicize substantial power saving is to say nothing at all. Originally, the fundamental purpose of developing variable-frequency air conditioner is to improve the quality of automatic regulation of air conditioner, replace on-off regulation with continuous regulation, reduce the fluctuation of room temperature, and achieve the purpose of comfort

low speed operation can indeed effectively reduce the noise of motor and compressor, but for split unit, the reduction of outdoor unit noise is of little significance to users. If the frequency conversion technology is applied to the whole window machine, it will be a very meaningful thing

second, the development direction of variable frequency air conditioning

at present, variable frequency air conditioning has roughly experienced the process from AC variable frequency air conditioning and DC variable frequency air conditioning to full DC digital variable frequency air conditioning. Among them, the latest is the full DC digital variable frequency air conditioner. As the heart of the full DC digital variable frequency air conditioner, the brushless DC motor compressor has the characteristics of significant energy saving, low noise and excellent speed regulation performance. Because the traditional DC motor compressor needs the inverter supplied by the given winding of the rotor position detection controller to commutation, which is unfavorable to reduce the cost of household appliances, reduce the volume of the device, and improve the reliability of air conditioning operation. It requires a DC brushless control system without position sensor. Now, some air-conditioning enterprises have introduced digital signal processor (DSP) for motor speed regulation, which is adopted by air-conditioning enterprises because of its compact structure, easy to use, high reliability, strong function and low cost. For example, Midea launched the "digital smart star" series of all DC digital variable frequency air conditioners, which has achieved the upgrading of domestic variable frequency air conditioners on the basis of comprehensively improving the performance of variable frequency air conditioners, marking that the air conditioning products of domestic household appliance enterprises have truly entered a new era of digital technology. From a worldwide perspective, variable frequency air conditioning represents the development direction of the air conditioning industry. For example, in Japan, variable frequency air conditioning has accounted for more than 80% of the air conditioning market sales, of which DC and full DC account for more than 70%. All DC digital frequency conversion technology is also the most advanced air conditioning technology in the world. Midea is undoubtedly at the forefront of the times and industry in this regard. It can be seen that the frequency conversion technology of digital processing (DSP) makes the air conditioner create a bionic environment close to nature, which greatly improves the air conditioning comfort of the human environment. In a word, the digital DC variable frequency air conditioner using pulse amplitude control (PAM) or pulse amplitude control (PAM) plus pulse width control (PWM) will become the development direction of variable frequency air conditioner in the future

in addition, with the continuous expansion of people's residential area and the continuous improvement of the quality of life, household central air conditioning came into being. The application of frequency conversion technology in household central air conditioning makes it have unique advantages. Compared with traditional household air conditioners, household variable frequency central air conditioners have greatly improved the indoor air quality and solved the problem of poor air quality in air-conditioned rooms. Household variable-frequency central air conditioners mostly use air duct system to supply air to the room. The air distribution of indoor air is reasonable, the temperature is uniform, the fluctuation is less, and the comfort is good. In terms of installation, it cooperates with the room decoration design to make the indoor unit or air duct hidden in the ceiling or wall, integrate into the overall effect of room decoration, improve the hidden dangers that affect the beauty and insecurity of the room due to the use of multiple split room air conditioners, and make the living environment elegant and comfortable

household variable frequency central air conditioner integrates the respective advantages of large central air conditioner and household variable frequency air conditioner in function. Compared with the large-scale central air conditioners currently used in hotels, restaurants and office buildings, household variable-frequency central air conditioners will be the largest user of intelligent composite materials in space, aerospace, convenient installation, energy saving and comfort. In terms of space utilization and use effect, household variable-frequency central air conditioning is a set of household type, which eliminates the need for machine rooms and floor by floor air supply ducts for large-scale central air conditioning, which not only saves building space, but also enables users to enjoy the comfort and comfort brought by household variable-frequency central air conditioning. Haier has launched the home variable frequency central air conditioning (MRV) system. The control system is advanced and highly intelligent. It adopts the variable frequency one drive multi technology of DSP speed chip digital signal processor, which is 20 times faster than ordinary air conditioning. Its control temperature response speed is fast and has strong functions. The temperature is constant at the temperature set by the user, reaching the precise range of temperature difference less than ± 0.5 ℃. This is the need and closeness for air conditioning to achieve high quality × The requirements of bionic natural environment laid the foundation. In addition, in addition to all the advantages of central air conditioning, the system also has the following remarkable characteristics: first, high efficiency and energy saving. We know that the energy consumption of air conditioning is mainly on the compressor and fan of rotating machinery. The gap of the separation surface of the compressor and fan of constant speed air conditioning should not exceed the rules in the table below, and it will change with the change of room heat load. Haier adopts hybrid vortex frequency conversion technology and digital frequency conversion one drag many technology, which can start at the low frequency of Hz to realize stepless regulation. Therefore, compared with Haier's traditional non frequency converter, it can save about 50% energy; Second, long service life. The starting current of the constant speed air conditioner is times that of the normal speed, and the household variable frequency central air conditioner (MRV) system using the hybrid vortex frequency conversion technology and the digital variable frequency one drive multi technology can realize zero current impulse starting, so that the compressor can avoid the impact of the maximum current during frequent starting, thus prolonging the service life of the air conditioner; Third, it is small and beautiful, and it is convenient for outdoor installation. For those modern high-end residential areas, it can also meet the needs of property managers for the neat and beautiful facade of the residential area; Fourth, there are many choices of indoor units, from wall mounted, floor mounted, suspended to hidden, with a total of 5 types and more than 20 kinds. All models embody the humanized design concept of the 21st century. With people's pursuit of life comfort, household M

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