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A Variable-Frequency Drive (VFD) is a power control device that applies frequency conversion and microelectronics technologies to regulate AC motors by altering the frequency of the power supply. Comprising rectifier circuits (AC to DC conversion), filters, inverters (DC to AC conversion), braking units, drive units, detection modules, and a microprocessor unit, the Minrong VFD frequency inverter adjusts the voltage and frequency of the output power through the switching of internal IGBTs. This allows the VFD to deliver the precise voltage required by the motor, achieving energy efficiency and speed control. Additionally, the drive is equipped with comprehensive protection functions, including overcurrent, overvoltage, and overload safeguards, ensuring reliable operation and equipment longevity.

Safety precautions for heavy-duty frequency inverters in high-temperature environments:

1：Monitor and carefully record the parameter readings on the VFD frequency inverter's human-machine interface (HMI). Report any anomalies immediately.
2：Monitor and record the ambient temperature in the inverter room, ensuring it remains between -5°C and 40°C. The temperature of the phase-shifting transformer should not exceed 130°C.
3：During high-temperature summer months, enhance ventilation and heat dissipation at the VFD installation site. The surrounding air should be free of excessive dust, salt, acid, corrosive, or explosive gases.
4：As summer coincides with the rainy season, protect the inverter from water ingress (e.g., rainwater entering through ventilation ducts).
5：Schedule regular cleanings. Clean the filter mesh on the VFD cabinet door weekly. Shorten the cleaning interval if the environment is dusty.
6：During normal operation, a standard A4 sheet of paper should adhere firmly to the intake filter mesh on the cabinet door.
7：Maintain a clean inverter room and promptly remove debris as needed.
8：Ensure adequate ventilation, lighting, and visibility in the inverter room. Cooling and ventilation equipment (e.g., air conditioners, fans) must operate reliably.

In large power electronic equipment, failure rates often increase with temperature. Therefore, the thermal design of high-power inverter systems directly impacts their reliability and stability. High-power, heavy-load inverters demand exceptional reliability. Thermal failures are the primary fault mode in power electronics—statistics show over 50% of electronic thermal failures result from temperatures exceeding rated limits. Structurally, effective heat dissipation is critical for normal operation.

SanKe VFD frequency inverters handle megawatt-level power, generating significant heat during operation. Optimizing ventilation and cooling systems through rigorous design calculations is essential to ensure efficient heat dissipation, thereby enhancing equipment reliability.

Heat dissipation calculation：

During normal operation, the heat sources of large-scale VFD frequency inverters include isolation transformers, power units, reactors, and control systems. Among these, the thermal design of power devices, power units, and power cabinets is of utmost importance. For IGBT or IGCT power devices, the PN junction temperature should not exceed 125°C, and the package shell temperature should be limited to 85°C. Studies have shown that when temperature fluctuations exceed ±20°C, the failure rate of the devices increases by 8 times.

Key points of cooling system design

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

(2) Reduce the heat output inside the equipment (device). Therefore, more low-power consumption devices, such as low-loss IGBTs, should be selected. In the circuit design, the number of heat-generating elements should be reduced, the switching frequency of the devices should be optimized, and the heat generation should be lowered.

(3) Adopting appropriate cooling methods and approaches can lower the ambient temperature and accelerate heat dissipation.