Research And Design Of Cooling Control Method For High Power Inverter

As one of the motor speed control method,frequency control has the advantages of stable speed regulation,stepless speed regulation,stable circuit and high efficiency energy conservation,which have been widely used in various cases.Nowadays,more and more high-power equipment is applied,and the power requirements for the inverter are also getting higher and higher,correspondingly,the heat loss of the system will also increase.These heat losses,if they are not released timely and efficiently,will severely affect the performance of the converter.Therefore,how to discharge heat loss of the high power inverter to ensure the temperature of power device is the key to ensure the normal operation of the inverter.At present,there are two kinds of methods that can be used to discharge heat loss,one is through using several IGBT with a low power rating in parallel to replace the IGBT with high power rating to spread the heat.The second is to select a reasonable heat transfer medium and designing an effective cooling control system to discharge heat loss.Therefore,this thesis mainly finished the following innovative work based on the inverter circuit of 600v/1 MW.Firstly,in order to reduce the loss of power devices,disperse heat source,reduce the surface temperature of the device,and reduce the design difficulty of temperature control system,we study the working principle and basic characteristics of IGBT.Besides,the influencing factors and solving methods of the current inequality of IGBT in parallel in inverter circuit is analyzed.Then,a system circuit structure based on IGBT is designed to enhance the heat dissipation function of the system.Secondly,in order to design the temperature control plan for the cooling system,the main power device heat loss of the cooling system is analyzed.Besides,the dynamic relationship between temperature and circulating water flow and fan speed is calculated according to the power device heat loss analysis.Finally,the overall structure of the heat dissipation system is designed.The cooling capacity of the system is improved by the combination of water-cooled and air-cooled cooling.Besides,by using the inverter to control the circulating water speed instead of using the throttle to control the circulating water speed,we can solve the shortcoming of flow rate instability and low adjustment accuracy by controlling the throttle flow.And the heat dissipation device model is established through using the Solidworks software.Besides,the control flow of the heat dissipation temperature control system is designed based on the analysis of the influence of the inlet flow rate and the temperature of the heat dissipation device on the effect of the heat dissipation in detail.Through the above research,we can show that: by designing a kind of IGBT parallel main circuit and adopting effective flow method,we can realize purposes of dispersing heat source,reducing switching loss and decreasing the difficulty of temperature control system design.Besides,the heat dissipation of the cooling system can be improved by the combination of water cooling and air cooling.Meanwhile,by determining the control strategy of the cooling control system,the temperature control can be achieved.