Variable-frequency Drive (VFD) is a power control device that uses frequency conversion technology and microelectronics technology to control AC motors by changing the working power frequency of the motor.

The frequency inverter is mainly composed of rectifier (AC to DC), filter, inverter (DC to AC), brake unit, drive unit, detection unit and micro-processing unit. The frequency inverter depends on the internal IGBT to adjust the output power supply voltage and frequency, according to the actual needs of the motor to provide the required power supply voltage, and then achieve the purpose of energy saving, speed regulation, in addition, the frequency inverter has a lot of protection functions, such as over current, over voltage, overload protection and so on.

Safety precautions for heavy-duty frequency inverter in high temperature environment:

1. Monitor and carefully record the parameter display on the man-machine interface of the frequency inverter, and report immediately if there is any abnormality.

2. Monitor and carefully record the ambient temperature of the inverter room, and the ambient temperature difference should be between -5 ° C and 40 ° C. The temperature of the phase-shifting transformer should not exceed 130 ° C.

3.When the temperature is high in summer, the installation site of the frequency inverter should strengthen ventilation and heat dissipation. The surrounding air should be free of excessive dust, salt, acid, corrosive and explosive gases.

4.At the same time, since summer is the rainy season, the frequency inverter should prevent rain from entering (such as rain entering the exit along the wind tunnel).

5.Schedule regular cleaning. The screen on the door of the frequency inverter cabinet should be cleaned once a week. If the working environment is dusty, the cleaning interval should be shortened according to the actual situation.

6.When working normally, a standard thickness of A4 paper should be firmly adsorbed on the filter screen of the air inlet of the cabinet door.

7.The frequency conversion room must be kept clean and cleaned at any time according to the actual situation on site.

8.The ventilation and lighting visibility of the frequency conversion room must be good, and the refrigeration and ventilation equipment (air conditioners, fans, etc.) can work normally.

In all large power electronics equipment, almost as the temperature increases, the failure rate of the equipment also increases. Therefore, the heat dissipation design of large frequency inverter power supply device is directly related to the reliability and stability of the equipment. High-power, high-load frequency inverters often require high reliability. The main form of power electronic equipment failure is thermal failure. According to statistics, more than 50% of electronic thermal failures are caused by temperature exceeding the rated value. From the structural design point of view, heat dissipation technology is the key to ensure the normal operation of equipment. Due to the large power of the heavy load frequency inverter equipment of Sanke Inverter Company, it is generally megawatt and generates a lot of heat during normal operation. In order to ensure the normal operation of the equipment, it is necessary to optimize the heat dissipation and ventilation scheme, carry out reasonable design and calculation, and realize the efficient heat dissipation of the equipment, which is necessary to improve the reliability of the equipment.

cooling sistem design points

(1) Select components and materials with good heat resistance and thermal stability to increase the allowable working temperature;

(2) reduce equipment (device) internal heat output. Therefore, more micro-power devices should be selected, such as low-loss IGBT, to reduce the number of heating elements in circuit design, optimize the switching frequency of the device, and reduce the heat output;

(3) using the appropriate cooling can reduce the environmental temperature and cooling way, speed up the heat.