The Design And Research Of Low Voltage Frequency Inverter Based On Thermal Simulation

Frequency inverter is being developed and applied widely in china, but because of its small size, high heat density and limited space for heat dissipation, it leads to very high device failure rate. Power module of inverter is high heat source, its temperature should be controlled within the permissible temperature range and the heat accumulated in the narrow space of product should be dissipated effectively. So it is very important to do thermal study and analyze of drive. In this article studies, the low voltage compact inverter of 11 KW need to work reliably and stably at high ambient temperatures of 50 degrees, it was deliberated research on the inverter cooling structure by means of three-dimensional structural modeling, mathematical modeling, thermal simulation, engineering experiments etc.(1) Sets up the mathematical model of the drive system cooling, and analyzes its heat transfer process and cooling mode, and analyzes the cooling design of natural convection and forced convection cooling in two different ways. Introduces the calculation method of thermal resistance of the heat sink, and on this basis to guide the design of the cooling structure.(2) Carries out detailed thermal design on 11 KW low-voltage inverter, including the selection of the fan, fan installation, heatsink detailed structural design and duct design. Isolates the main heat source and PCB by using the unique air duct design, in order to improve the reliability and lifetime of inverter. And utilize UG software for the initial cooling three-dimensional structure of the drive physical model.(3) According to drive thermal structure of the design, using Icepak software building thermal simulation model to analyze the inverter cooling system design. Focus on the hot spot temperature of the inverter by Finite element simulation results; observes the distribution of the wind inside the inverter visually, velocity vectors and temperature contours by Icepak powerful visualization post-processing functionality, then accordingly guide and optimize thermal design of the inverter until the results of the thermal simulation and design work to fully meet the requirements of the drive.(4) Builds up engineering prototypes of drive after optimizing cooling solution, and executes thermal test on prototypes in accordance with the design requirements of 50 degrees ambient temperature and by pre-attaching thermocouple to the core components of drive in order to monitor drive real-time operation temperatures. According to the results of thermal testing, the actual temperature measured and thermal simulation result it is matched well, which we also tested the thermal design simulation accuracy and reliability.Researches on the thermal design and simulation, can quickly predict the temperature of the power module and internal temperature and wind distribution, then optimize the cooling structure of drive based on the simulation results, it provides an effective method of the new drive research and development.