Research On The Key Technologies Of High-power And Ultra-audio Frequency Induction Heating Power Supply

With the rapid development of optical communication technology, the demand of the optical fiber is increasing, and the performance of high-power ultra-audio frequency induction heating power supply which is widely used in optical fiber production is also rising. At present, the main induction heating power supply used in our country to produce fiber is series-resonance, however parallel-resonance induction heating power supply with the advantage of easy overcurrent protection, handy output wiring and flexible load impedance has great potential market in fiber production. The paper studies key technologies of high-power and ultra-audio frequency induction heating power supply on the basis of 100kW/18kHz parallel-resonance induction heating power supply.Firstly, the paper gives a brief introduction of the background, significance and fiber production technology. Then it introduced induction heating and analysis power adjustment program of high-power and ultra-audio induction heating power supply and uses the three-phase uncontrolled rectifier and BUCK chopper power scheme. It analysis series and parallel inverter works departure from the series and parallel load characteristics. Secondly, the paper focuses on three key technologies of induction heating power supply:sweep startup, frequency tracking and impedance matching. For the original start-up mode, the paper uses software sweep startup. It takes advantage of PI-SPLL phase locked loop to achieve frequency real-time tracking. It uses the best overlap region and output phase angle control. The impedance matching is consisted of electromagnetic and electrostatic coupling, and the paper pays more attention to the third-order matching circuit, undercompensation and overcompensation.The paper begins to design power supply based on the sufficient theoretical study, and carries on the main circuit simulation and thermal simulation. Finally the paper designs a parallel-resonance 100kW/18kHz induction heating power supply prototypes to test. The test result is consistent with simulation, theoretical design and it complies with the electrical design requirements. The result verifies the key technologies of high-power induction heating power supply:sweep startup control strategy, PI-SPLL frequency tracking control strategy, impedance matching. High-speed processing of digital control system based on DSP chip TMS320F28335 achieves high stability of power output. The power supply can be stable and reliable operation in the actual conditions. It has an important significance in domestic ultra-audio frequency induction heating power supply research.