In recent years, the energy saving project of the motor system has been an important part of the national energy conservation medium- and long-term planning and the eleventh and fifty-key key energy-saving projects. On the basis of updating and renovating the motor, the energy-saving method of improving the operating efficiency based on frequency conversion and speed regulation is widely recognized by the industry.
As an important energy-saving technology, the frequency conversion technology can change the power supply frequency of the power equipment in real time, thereby achieving the purpose of controlling the output power of the equipment. The technology changes the output power of the shaft through frequency conversion speed regulation, so that the motor can output power according to actual needs, and achieves the purpose of reducing input power and saving electric energy. Compared with the conventional fixed speed motor, the motor system can reduce energy consumption by up to 30% after frequency conversion. the above .
Due to the backward adjustment of the motor system in China, most of the fan and pump adjustments still use mechanical baffle throttling, which makes the rotary encoder 30% lower than that of developed countries. Relevant experts pointed out that the advanced power electronic frequency conversion speed regulation replaces the traditional The method of DC motor speed regulation can improve the efficiency and achieve energy saving effect.
In the petroleum and chemical industry, the amount of motor drive equipment such as fans, pumps and compressors is very large. In theory, frequency conversion technology can be used for energy-saving retrofit, and the energy-saving potential is huge. Taking the injection molding machine as an example, the traditional quantitative pump on the injection molding machine is transformed into a variable frequency variable pump, which can minimize the return flow of the relief valve, avoid the energy loss of the high pressure throttling, and then the traditional high pressure throttling. The energy-consuming injection molding machine is upgraded to an energy-saving injection molding machine without high-pressure throttling, and the power saving efficiency can reach 20% to 30% or more.
At the same time, the variable frequency drive speed regulation has the following five characteristics: one is that the original equipment is not changed, including the motor itself; the second is that the stepless speed regulation can be realized to meet the requirements of the transmission equipment; the third is the soft start and soft stop of the frequency converter. Function, can avoid the adverse effect of starting current impact on the power grid, reduce the power supply capacity, reduce the mechanical inertia and reduce the mechanical loss; Fourth, it is not affected by the power frequency, and can be open-loop or closed-loop manual/automatic control; When the speed is low, the fixed torque output and the low speed overload capability are better; the power factor of the motor increases as the speed increases and the power increases.
The frequency conversion energy-saving of the motor is gradually recognized by people, and it also drives the prosperity of the inverter market. At present, China's AC motor frequency conversion speed regulation market is developing rapidly, with an annual growth rate of 12%. Various high and low voltage inverters have been promoted and applied in the energy saving of motor systems. According to statistics, in 2009, the sales of China's low-voltage inverters reached 13 billion yuan, and hundreds of domestic enterprises and brands emerged. Its total output value exceeded 4 billion yuan, accounting for 30% of the market. High-voltage inverters are the focus of current motor energy conservation. The localization rate accounts for 60% of the market share.
In terms of frequency conversion energy-saving standards, China currently has a national standard for motor frequency conversion energy-saving devices. According to reports, as early as the early 1980s, experts concerned proposed to implement motor frequency conversion speed regulation energy-saving technology in China.
During the fifteenth period, China carried out energy-saving renovation of motor and motor drive systems: During the 11th Five-Year Plan period, the state proposed to optimize the transformation of LDO energy-saving fans, pumps and compressor systems in the construction, electric power and other industries, and promoted variable frequency speed control and automation system control. Technology lays a good foundation for the promotion and application of motor energy-saving technology. During the 12th Five-Year Plan period, the motor industry presents various opportunities and challenges in terms of innovation and transformation. For the sustainable and healthy development of the motor industry and the potential of energy saving in motor systems, the use of frequency conversion technology will undoubtedly bring great benefits. Chen Weihua told reporters: The motor industry must seize the favorable opportunity of the country to develop and cultivate strategic emerging industries and promote energy-saving projects in motor systems, vigorously carry out technological innovation and business innovation, and accelerate the transformation of structural adjustment and development mode.
How to effectively promote the energy-saving work of the motor? Zhang Xin, assistant to the president of China National Institute of Standardization, suggested establishing a mechanism led by the department and involving multiple units to integrate single and decentralized systems, implement contract energy management in the motor field, and use market mechanisms to promote energy-saving conversion of low-efficiency motors.