Research On A High Power Motor Maintenance Power Supply

After the nuclear power unit is operated for a long time,the end of the large motor is worn out,and the stator end winding of the generator has a relatively serious phenomenon of grinding yellow powder.As the running time increases,the degree of wear will become more and more serious.Need to go through the yellow powder treatment and maintenance work,such as coil shaping and replacement.The large motor bar through-flow heating device can be softened by heating the wire rod,thereby replacing the current manual processing method,and removing the wire rod from the motor slot without damaging the insulation.The large-scale motor bar through-flow heating device is essentially a low-voltage and high-current power supply,which generally requires a low output voltage of the power supply and a large current,and the power supply power requirement is relatively high.This paper designs a 10 KW three-phase interleaved digital power system with output of 100V/100 A.Firstly,the motor maintenance power supply is introduced from the overall structure,and the working principle of the interleaved Buck topology is analyzed.Then we studied the control method of the power supply.Firstly,the characteristics of the power supply are analyzed.The three-phase interleaved parallel Buck circuit is used as the main topology,and the power supply characteristics are analyzed.The simulation results show that the method can reduce the output current ripple of the power supply and effectively improve the dynamic performance.Then the control algorithm of the power supply is introduced,and the PI control algorithm is selected by comparison.In order to solve the current sharing problem of three-phase interleaved digital power supply,a maximum current automatic current sharing method is designed.The final experimental results show that the control method can achieve a load sharing imbalance of less than 4%.In order to ensure the accuracy of the acquired signal,this paper designs a digital filtering method based on the improved cat group algorithm,and compares it with other algorithms such as particle swarm,which proves that the method has the characteristics of fast convergence.The power hardware part selects TMS320F28335 as the controller,and designs related DC-DC main circuit and digital circuit.The software design mainly includes three-phase PWM algorithm,AD sampling program,digital PI algorithm,CAN bus communication program and current sharing program.Finally,the test prototype of three-phase interleaved buck is designed and tested.The experimental results show that the high-power motor maintenance power supply designed in this paper can meet the expected technical specifications.