稳压式变极性焊接电源二次逆变拓扑及控制策略

Topology of secondary inverter and its control strategy of variable polarity welding power supply for generating stabilized reverse voltage

文中提出了一种新型稳压式变极性焊接电源二次逆变电路拓扑.通过合理地控制二次逆变电路中功率器件的开通和关断,其中的反向稳压电路可以在焊接电流的极性变换过程中产生稳定的反向电压,促使焊接电流快速过零.对二次逆变的换流过程进行了深入分析,导出了换流时间和关键节点电流的理论计算公式,研究了耦合电感值和功率器件共同导通时间对换流过程的影响规律.对电源输出电流和电缆两端电压波形进行了实际测试.结果表明,利用所提出的二次逆变电路拓扑及其控制策略可以实现电流极性的快速转换,波形无畸变.

An innovative secondary inverter circuit topology of variable polarity power supply is proposed for generating stabilized reverse voltage. Through reasonable control in the turn-on and turn-off of power devices in secondary inverter circuit,the reverse stabilized voltage generating circuits is able to generate stable reverse voltage during the polarity commutation procedure of welding current,to guarantee the welding current passing zero rapidly. By deeply analyzing the current commutation procedure of secondary inverter,theoretical calculation formulas of current commutation time and current values at key time points are derived,then the governing laws of coupling inductor value and common conduction time of power devices on the current commutation procedure,including the current commutation time and current values at key time points,are researched.Then,a test platform of variable polarity welding power supply is constructed,and the waveforms of output current of power supply and voltage on both ends of output cable are measured practically. The experimental results prove that the proposed secondary inverter circuit topology and its control strategy are feasible to realize the rapid commutation of current polarity,and the variable polarity current waveform has no distortion.