Thermal solution for inverter
With the reduction of the overall size of photovoltaic inverter and the improvement of single machine power, the requirements for thermal design are higher and higher. The designer must comprehensively consider the heat dissipation effect, protection, installability, maintainability and economic cost of the inverter cooling system. Among them, the power of single machine is an important basis for the design of thermal solution.
Inverter cooling technology includes natural cooling, forced air cooling, liquid cooling and phase change cooling. The research shows that the cooling efficiency of forced air cooling is 10 ~ 20 times that of natural cooling, and the more efficient way of heat dissipation is liquid cooling.
From the structural complexity and the difficulty of realization, the forced air cooling system is simpler, easier to realize and more reliable than the liquid cooling system. Therefore, forced air cooling is preferred in the power industry, followed by natural cooling, liquid cooling and other heat dissipation methods.
Generally, the allowable working temperature rise of electronic components is within the range of 40 ~ 60 ℃. Under the allowable upper limit of temperature rise of 60 ℃, natural cooling can bear the maximum heat flux of 0.05w/cm2.
When the heat flux is greater than 0.05w/cm2, natural cooling can barely improve the heat dissipation effect through some special means, but it needs to sacrifice the working performance, device life or economy. When the heat flux is greater than 0.05w/cm2, the forced air cooling heat dissipation method can obtain satisfactory comprehensive performance and economy.
When the heat flux continues to increase, other heat dissipation methods such as liquid cooling need to be selected. For large-scale wind energy converters with a power of several MW, the heat dissipation mode is liquid cooling.
Thermal cooling technology includes natural cooling, forced air cooling, liquid cooling, phase change cooling and other forms, which are mainly selected according to the power of the inverter.
