【摘要】 通过对电压负反馈配合电流正反馈的送丝调速系统与转速负反馈调速系统的比较,得出了这两种调速系统的等效条件.设计了一种基于TL494芯片的电压负反馈配合电流正反馈的CO2焊机送丝调速电路.该电路通过PWM脉宽调制,实现转速的均匀调节,并具有过电流截止保护功能.通过实验,验证了该调速电路的可靠性.实验中,当电源电压由342V变到418V,负载从25N变到50N时,送丝速度的变化率小于5%,符合JB/T9533 1999专业标准要求.更多还原

【Abstract】 By the comparison of the voltage negative feedback wire-feeding speed regulation system supported by current positive feedback and the rotational speed negative feedback regulation system, the equivalent condition of the two systems is obtained. Then, a wire-feeding speed regulation circuit for the CO2 welding machine is designed based on TL494 chip. Owing to the adoption of the pulse width modulation technology, the motor of the system can run smoothly at adjustable speeds, and the system also has the self-protective function under the condition of current overloading. The reliability of the circuit is verified by experiments. In the experiments, when the power voltage varies from 342V to 418V, and the load from 25N to 50N, the variation ratio of the wire-feeding speed is smaller than 5%, which satisfies the JB/T9533-1999 professional standard.更多还原