Research On High Power Factor Welding Power Based On Snubber Capacitor

Welding power is the main equipment commonly used in equipment manufacturing enterprises.Its power consumption directly affects the manufacturing cost of the product.Although the enterprise uses advanced welding power,there is still a problem of low power utilization.Through the analysis of the working principle and power quality of the welding power supply in a large enterprise,the main reason is that the input current waveform distortion is serious,and the full-bridge DC-DC converter works in the hard switching mode.Thus,a new active power factor correction system is proposed in this paper,which ean effectively improve the input current waveform and provide a stable DC power supply for the latter stage circuit.Then,for the full-bridge DC-DC converter,the application of the snubber capacitor to participate in the working process is proposed.The theory,based on the combination of the dead zone phase shift control strategy,makes the full bridge DC-DC converter work in the full soft switching state.The new Active Power Factor Correction(APFC)system proposed in this paper is based on single-phase boosting power factor correction(Single-phase Boost PFC)circuit,and three-channel circuit model is established by using interleaved parallel technology,and the three-channel interleaved Boost PFC circuit is combined with the three-phase single-switch PFC circuit.The voltage and current double closed-loop control system is designed by state space averaging method,and the simulation model is built on Matlab/Simulink software platform to obtain the result.Then the problem of the input current is partially sinusoidally followed by the input voltage at 2 times frequency is optimized.An LRC ripple absorption circuit is formed at the input end of the power supply to build a new high-power three-phase APFC system close to "zero ripple".Finally,The optimized system simulation model was established on the Matlab/Simulink software platform,and the ideal results were obtained.In this paper,based on the analysis of the capacitance function of the full-bridge DC-DC converter circuit in parallel with the main switch tube,a full-bridge DC-DC converter circuit based on snubber capacitor is designed.The snubber capacitor in this circuit can not only effectively improve the voltage waveform characteristics(du/dt)generated during the operation of the high-frequency transformer,but also reduce the damage to the transformer insulation protection,and can realize the zero voltage(ZVS)turn-off and zero voltage zero current(ZVZCS)turn-on in the circuit by combining with the dead zone phase shift control technology.It ensure that the system operates in a fully soft switching state,greatly reducing the system's switching losses.Finally,the simulation results verify the theoretical correctness of the snubber capacitor in suppressing the high-frequency link du/dt and realizing the operating state of the full soft switch.Finally,the capacitor buffered full-bridge circuit experiment was carried out with MEGA8+SG3525 as the control chip.A 1KW experimental prototype was built,and the function of the buffer capacitor was verified by analyzing the collected experimental waveforms.