The supplier of the energy feedback device for the frequency converter reminds you that in 1967, the frequency converter was successfully developed and put into commercial operation. After more than 40 years of development, variable frequency speed regulation of AC motors has become a major means of saving electricity, improving production processes, enhancing product quality, and improving operating environments. Variable frequency drives are widely favored by users for their high efficiency, high power factor, and excellent speed regulation and braking performance. They play the following three important roles in many fields:
（1） Soft start function. When a motor is hard started, the direct starting current is often 3-5 times its rated current. The sudden increase in current not only increases the difficulty of motor design and production, but also has a serious impact on the capacity of the power grid system, transmission and distribution facilities, and causes great damage to equipment such as baffles and valves. The function of a frequency converter is to change the frequency and amplitude of the AC motor power supply, thereby changing the period of its moving magnetic field and achieving smooth control of the motor speed. This causes the starting current of the motor to start from zero and gradually increase, with the maximum value not exceeding the rated current, reducing the impact on the power grid and the requirements for power supply capacity, and extending the service life of the equipment.
（2） Optimize motor operation. In systems such as fans and central air conditioning, traditional water supply methods are achieved through facilities such as water towers, high-level water tanks, and pressure tanks. The water pressure at the outlet is often affected by factors such as the height and storage capacity of the water tank, and it often changes. It is not easy to truly achieve constant pressure. In addition, the traditional speed control method for equipment such as fans and pumps relies on adjusting the opening of inlet and outlet baffles and valves to regulate the air and water supply volume. When the input power is too high, a large amount of energy is consumed in the blocking process of the baffle and valve, resulting in waste. This is like people transporting bricks that greatly exceed the demand to high-rise buildings without accurately calculating the quantity of work, resulting in a waste of manpower and working hours. Nowadays, engineers combine frequency converters, PID regulators, microcontrollers, PLCs, etc. to form a control system that can regulate the output flow of water pumps and reduce ineffective labor. People only need to set the outlet pressure of the pump station main pipe, compare the set value with the actual feedback value, and after the difference is processed through calculation, the system will issue control instructions to control the number and speed of water pump motors in operation, thus achieving the goal of constant pressure in the water supply main pipe. Compared with regulating valves to control water pressure, this system reduces pipeline resistance, greatly reduces the efficiency of interception losses, and does not require frequent manual operation, reducing labor intensity. In central air conditioning, fan and other systems, frequency converters also perform well. China Inverter Network pointed out that central air conditioning is designed based on the maximum required cooling (heating) capacity plus 10-20%, with high power consumption and great energy-saving potential. By using a frequency converter to control the speed and energy efficiency of central air conditioning refrigeration compressors, refrigeration pumps, cooling pumps, cooling tower fans, return air devices, etc., it is possible to avoid excessive flow and pressure, ensure the normal and effective operation of the system, and save 20% to 50% of electricity. For example, during the construction of the Shanghai Yangtze River Tunnel, the builders need to ensure good ventilation inside the tunnel, which is approximately 8.9 kilometers long and has an inner diameter of 13.7 meters. For this purpose, this project uses a frequency converter to directly set the motor speed based on the air volume, accurately adjust the air volume, optimize the use of electrical facilities, and achieve energy savings of 20% -45%.
（3） It has a protective function for the system. After detecting abnormal states in the system, the frequency converter can automatically correct the action or block the PWM control signal of the power semiconductor device, causing the motor to automatically stop, such as overcurrent stall prevention, overcurrent cut-off, semiconductor cooling fan overheating, and instantaneous power outage protection.