电火花沉积脉冲电源的改进及仿真分析

发布时间：2018-06-13 01:39

本文选题：电火花沉积 + 脉冲电源　；参考：《青岛理工大学》2017年硕士论文

【摘要】：电火花沉积技术作为一种金属表面处理技术,在金属表面强化和零件损伤修复领域取得广泛的应用。脉冲电源作为电火花沉积系统中的关键部分,其性能对电火花沉积加工效果具有重大的影响。晶体管控制的RC脉冲电源是电火花沉积加工常用的脉冲电源,其单次脉冲放电能量和脉冲频率分别与电容容量呈现正相关、负相关。当进行大功率电火花沉积加工时,具有电容量较高、脉冲频率较低、沉积效率较慢的缺点;当进行普通功率电火花沉积加工时,具有脉冲频率偏低、沉积效率偏慢的缺点。针对这一问题,对该脉冲电源进行改进,利用计算机仿真技术对改进后脉冲电源的沉积效率进行验证,对脉冲电源的改进策略进行试验验证。首先,对电火花沉积系统中晶体管控制的RC脉冲电源进行分析,发现该脉冲电源存在的问题。为了达到提高沉积效率的目的,从电压的调节方式、充放电方式和系统控制方式三个方面考虑,提出了脉冲电源改进方案。基于“二级整流逆变”原理,依次采用全波桥式整流器、滤波器、全波桥式逆变器、隔离变压器以及全波桥式整流器等元器件对电源进行变压,连续调节电容器的充电电压。基于“多路充放电”原理,采用多个独立充放电回路,减小过大的脉冲间隔;另外,充电回路使用可调限流电阻器取代固定限流电阻器,使脉冲间隔尽可能缩小至理想值。基于“相关联时序控制”原理,在开关电源与限流电阻器之间使用IGBT作充电开关元件,使得放电开关SCR可以及时关断。为了实现每条充放电回路的协同工作,可以通过时钟电路控制各充放电回路的放电开关和充电开关的开关状态。其次,在完成脉冲电源改进的基础上,对该电源的大功率电火花沉积过程进行了非线性瞬态温度场仿真分析与热应力场仿真分析。分析结果表明该脉冲电源可以提高电火花沉积效率,电火花沉积效率随着脉冲电源脉冲间隔的减小而增加。最后进行电火花沉积试验,结果表明通过适当缩短脉冲间隔及降低比沉积时间来改进脉冲电源的改进策略能够提升电火花沉积效率。
[Abstract]:As a kind of metal surface treatment technology, EDM has been widely used in metal surface strengthening and parts damage repair. Pulse power supply is a key part of EDM system, and its performance has great influence on EDM effect. The RC pulse power supply controlled by transistor is a common pulse power supply for EDM. The single pulse discharge energy and pulse frequency are positively correlated with capacitance and negatively correlated with capacitance. When high power EDM is carried out, it has the disadvantages of high capacitance, low pulse frequency and slow deposition efficiency, and low pulse frequency and low deposition efficiency when common power EDM is carried out. Aiming at this problem, the pulse power supply is improved, the deposition efficiency of the improved pulse power supply is verified by computer simulation technology, and the improved strategy of the pulse power supply is tested and verified. Firstly, the RC pulse power supply controlled by transistor in the EDM system is analyzed, and the problems of the pulse power supply are found. In order to improve deposition efficiency, an improved scheme of pulse power supply is proposed from three aspects: voltage regulation mode, charge and discharge mode and system control mode. Based on the principle of "two-stage rectifier inverter", components such as full-wave bridge rectifier, filter, full-wave bridge inverter, isolation transformer and full-wave bridge rectifier are used to continuously adjust the charging voltage of capacitor. Based on the principle of "multi-channel charging and discharging", several independent charge and discharge circuits are adopted to reduce the excessive pulse interval. In addition, the adjustable current limiting resistor is used to replace the fixed current limiting resistor in the charging loop, so that the pulse interval is reduced to an ideal value as far as possible. Based on the principle of "associated timing control", IGBT is used as the charging switch element between the switching power supply and the current limiting resistor, so that the discharge switch SCR can be turned off in time. In order to realize the cooperative work of each charge and discharge circuit, the switching state of each charge and discharge circuit can be controlled by the clock circuit. Secondly, on the basis of the improvement of pulse power supply, the nonlinear transient temperature field simulation analysis and thermal stress field simulation analysis are carried out for the high power EDM deposition process. The results show that the EDM deposition efficiency can be improved by the pulse power supply, and the EDM deposition efficiency increases with the pulse interval decreasing. Finally, the experiment of EDM deposition is carried out. The results show that the improvement strategy of pulse power supply can improve the efficiency of EDM deposition by shortening the pulse interval and reducing the specific deposition time.
【学位授予单位】：青岛理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG174.4

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