Development and application analysis of motor frequency conversion control
In the initial time, China's motor frequency was fixed, and the motor could only output a fixed power, a voltage. Therefore, the driving frequency of the motor at the time of operation is completely unchanged. However, the driving frequency required for the load is constantly changing. In order to meet the driving frequency required by the load, the rated driving frequency of the motor is generally greater than the driving frequency required by the load. Although this can ensure that the motor provides sufficient driving frequency to ensure the normal operation of the motor, a large part of the driving frequency will be wasted, which causes a large amount of electric energy to be wasted and cannot be effectively utilized. Does not meet the strategic requirements of China's sustainable development.
In order to save power and make full use of electric power, motor frequency conversion control technology has been developed. The motor frequency conversion control can change the power and voltage of the motor output according to the driving frequency required by the load, so as to ensure that no extra drive is driven. Waste, a good increase in the utilization of electrical energy, fully in line with China's energy-saving emission reduction requirements. As China's requirements for energy conservation and emission reduction are getting higher and higher, the development and research of variable frequency energy-saving control systems are constantly improving, and have been better promoted and applied in more and more places.
1) Development process of motor frequency conversion technology
The current motor frequency conversion system is mostly a constant V/F control system. The frequency conversion control system is characterized by simple structure and low production. This system is widely used in large-scale wind turbines and places where the dynamic performance requirements of frequency conversion systems are not very high. This system is a typical open-loop control system that can meet the smooth shifting requirements of most motors, but has limited dynamic and static regulation performance and cannot be applied to dynamic and static performance requirements. local.
In order to achieve high performance of dynamic and static regulation, we can only use a closed-loop control system. Therefore, some researchers have proposed a motor speed control method that controls the closed-loop slip frequency. This type of speed regulation can achieve high performance in static dynamic speed regulation, but this system can only be obtained in a motor with a relatively slow speed. The application should be such that when the motor speed is high, the system will not only achieve the purpose of saving energy, but also cause the motor to generate a large transient current, so that the torque of the motor changes instantaneously. Therefore, in order to achieve higher dynamic and static performance in higher speeds, only the problem of transient current generated by the motor can be solved first. Only by properly solving this problem can we better develop the motor variable frequency energy-saving control technology.
2) Application of motor frequency conversion control
About 70% of the energy consumption of the motor is applied to the load of the fan and the pump. Therefore, the motor frequency conversion control technology can save the energy consumption of this part of the load and achieve the purpose of energy saving and emission reduction. . Take the air conditioner as an example. If the air conditioner without the inverter control system is used, when the set temperature is lower than the threshold, it can only be realized by closing the airway. However, the motor of the air conditioner is still running at this time. Some of the drive power is completely unused, but it is simply wasted. However, in the air conditioner that wins the inverter control system, if the temperature of the air conditioner is lowered, it is only necessary to control the rotation speed of the motor to be reduced, and the driving power of the output can be reduced. It is not necessary to turn off the air passage, and it is not necessary. It will waste the driving frequency of the motor and improve the utilization efficiency of the electric energy.
03, conclusion
In order to comply with the requirements of the national sustainable development strategy, the power system vigorously promotes the motor frequency conversion energy-saving control system. The application of this system has largely alleviated the current situation of China's power shortage. The motor frequency conversion energy-saving control system can reduce the output of unnecessary driving frequency of the motor and achieve reasonable application of power.
