With the continuous improvement of industrial automation, frequency converters have been widely used. Energy conservation and environmental protection are the core of my country's industrial economic development. While pointing the way for the sustainable development of my country's industry, they are also effectively driving the sustainable development of my country's frequency converter industry, enabling the industry to continuously expand its market share and become an important cornerstone of my country's industrial economic development with its strong development momentum.
Variable frequency drive (VFD) energy saving is mainly used in situations where it is necessary to change the characteristics of the drive machinery by varying the speed of the AC motor to meet production process requirements. It is frequently used in fans and water pumps. When a motor can only operate at its rated speed, its drive machinery can only operate at a certain rated speed.
When production processes require adjustments to process parameters, the flow rate can only be forcibly changed by increasing (or decreasing) the system resistance. The motor, however, always operates at its rated condition, resulting in wasted energy. Traditional speed control methods for equipment such as fans and pumps involve adjusting the opening of outlet (or inlet) baffles and valves to regulate air and water flow. Besides wasting energy, this increases system accessories and the probability of system failure. When using variable frequency speed control, if the required flow rate decreases, the pump or fan speed can be reduced to meet the requirement.
In summary, frequency converters primarily achieve energy savings through two methods: power factor compensation and soft starting. Regarding power factor compensation, reactive power increases line losses and equipment heat generation. Furthermore, a lower power factor leads to a decrease in the active power of the grid, resulting in significant reactive energy consumption in the lines, low equipment efficiency, and substantial waste. By using a variable frequency drive (VFD), the internal filter capacitors of the VFD reduce reactive power losses and increase the active power of the grid.
In terms of energy saving through soft starting, hard starting of motors can severely impact the power grid and place excessive demands on grid capacity. The large current and vibrations generated during startup can cause significant damage to baffles and valves, severely impacting the lifespan of equipment and pipelines. However, utilizing the soft-start function of a frequency converter allows the starting current to begin from zero, reducing the impact on the power grid and the demand on power supply capacity, extending the lifespan of equipment and valves, and thus saving on equipment maintenance costs.
However, it's important to avoid the "underpowered" problem when using frequency converters. This issue arises because the operating conditions at the time of design and production limited resources, leading to the use of frequency converters with power ratings lower than the motor's rated power in many areas to save costs. However, with technological advancements and changes in production processes, the "underpowered" problem inevitably resurfaces, causing the frequency converter to malfunction.
Therefore, during the trial period of the frequency converter, to prevent problems from occurring, testing and adjustments should be carried out in advance. Furthermore, after 6 to 10 years of normal use, the frequency converter is prone to entering a period of high failure rate, frequently experiencing component burnout, failure, and frequent activation of protection functions, seriously affecting its normal operation.
