Research On Medium-Frequency Induction Power Supply For Pre-Heating And Post-Weld Heat Treatment Of Nuclear Pressure Vessel

In order to meet the requirements of medium-frequency induction heating power supply requirements for weld preheating and post-weld heat treatment for thick-wall pressure vessels of nuclear power,controllable temperature and speed,stable temperature,long working time and frequent start.In this paper,the inverter bridge composed of DSP control IGBT inverter module and the medium-frequency induction heating power supply for the whole system by ARM as the research object,has completed a 10kHz/80 kW series resonant intermediate frequency induction power supply.Firstly,The principle of induction heating and the development status and trend of induction power supply were introduced.Then the advantages and disadvantages of the power regulation mode and the inverter circuit structure are compared and analyzed,and the system scheme of the inverter power regulation and the series resonant voltage inverter circuit is determined.Paper focuses on the analysis and design of the mode of following frequency and phase lock by DSP and temperature control strategy of medium-frequency induction heating power supply,and the power supply has the advantages of fast following frequency locking and good temperature control.In the power regulation strategy,the way of adjusting the shifting-phase angle by PI to realize the fast and accurate adjustment of the power.In the aspect of phase following and phase locking,DSP get IGBT output current zero crossing signal,to realize the fast tracking frequency and locking phase of the natural frequency of the load.According to the requirement of power supply,the electrical parameters of the main circuit were calculated,and the key components were selected.According to the parameters of IGBT,a IGBT driving board is designed,the driving board composed of driving module and flyback isolation switching power supply,and driving module is supplied by flyback isolation switching power supply.In the temperature control strategy,the energy temperature control algorithm is programmed.Through the USB read-write module,the actual-time temperature,power and heating time of the workpiece is stored in the USB flash disk.The correctness of the theoretical analysis and design is verified by simulating the main circuit of the power supply through a software,MATLAB/Simulink.At last,a high performance 10kHz/80 kW series resonant medium-frequency induction heating power supply has been successfully developed.Through the test,it shows that the performance of the medium-frequency induction heating power supply has reached the expected target,with stable output power and high precision control of workpiece temperature,which meets the requirements.