A lot of experimental methods have been brought forth to assess the dynamic character of the arc welding power source, but up to now, this issue has not been solved very well. In this paper, based on the fuzzy logic r...A lot of experimental methods have been brought forth to assess the dynamic character of the arc welding power source, but up to now, this issue has not been solved very well. In this paper, based on the fuzzy logic reasoning method, a dynamic character assessing model for the arc welding power source was established and used to analyze the dynamic character of the welding power source. Three different types of welding machine have been tested, and the characteristic information of the electrical signals such as re-striking arc voltage, low welding current and so on of the welding process were extracted accurately by using a self-developed welding dynamic arc wavelet analyzer. The experimental results indicate that this model can be used as a new assessing method for the dynamic character of the arc welding power source.展开更多
A high frequency pulse power source for TIG welding is developed. The structure of two powers is adopted. The by pass circuit effectively eliminates the effect of the cable equivalent inductance. The maximum frequenc...A high frequency pulse power source for TIG welding is developed. The structure of two powers is adopted. The by pass circuit effectively eliminates the effect of the cable equivalent inductance. The maximum frequency of the output pulse current reaches to 16 kHz . The base current and the peak current can be regulated separately.展开更多
This paper analyses the performance request of arc welding power source used in intelligent control of weld pool shape in pulsed GTAW, and develops a sample power source. The main circuit of the power source takes the...This paper analyses the performance request of arc welding power source used in intelligent control of weld pool shape in pulsed GTAW, and develops a sample power source. The main circuit of the power source takes the structure of single ended inverter with two switches, and takes IGBTs as power switches. The working frequency of the inverter is set at 20 kHz. The control circuit takes PWM circuit as center, and uses single chip computer to complete the manage functions such as the control of working sequence, setting and changing of the welding parameters, sensing of the welding states and communication with outside computer etc. The dynamic reacting time of the whole power is 1 ms, the range of the output current is 5～250 A, the precision of the output current reaches to 1 A. The power strikes arc by contacting workpiece under 5 A, and have convenient interface with system computer. All above shows this power source is one with high performance.展开更多
The full bridge zero voltage zero current switching （ FB-ZVZCS ） , which could adjust the output power by keeping the duty ratio of lagging leg constant and changing the duty ratio of leading leg, was a common circu...The full bridge zero voltage zero current switching （ FB-ZVZCS ） , which could adjust the output power by keeping the duty ratio of lagging leg constant and changing the duty ratio of leading leg, was a common circuit of soft switching arc welding inverter power source. However, when the duty ratio of leading leg was reduced to zero, the output power stayed the constant value instead of becoming zero. The working status and waveforms of some major parameters were studied in this paper while the duty ratio of leading leg was zero. It was concluded that the minimum output power of soft switching inverter was related to the charging voltage of paraUel capacitors, and the output power also could be reduced by reducing the duty ratio of lagging leg. A novel two-stage continuous PWM control method that could switch working-mode between full bridge and half bridge was put forward in this paper. This kind of control method could further reduce the output power of soft switching inverter in order to meet the requirement of low heat input of sheet metal welding.展开更多
The welding process essentially is a complicated nonlinear system with time-varying, uncertain, strong-coupling characteristics, so it is difficult to get high welding quality by traditional control approaches such as...The welding process essentially is a complicated nonlinear system with time-varying, uncertain, strong-coupling characteristics, so it is difficult to get high welding quality by traditional control approaches such as the standard proportionalintegral （ PI） algorithm. A new algorithm based on artificial neural network （ANN） is presented to achieve optimal P1 parameters and improve its adaptability. First, main parameters of artificial neural network are researched to improve the convergence rate and system stability. Then, six expert rules are proposed to constitute the expert adaptive ANN-PI algorithm. Experimental results show that the welding current control system＇has high dynamic response rate, and the welding process is stable.展开更多
基金This work is supported by Guangdong Natural Science Fund (04020100)
文摘A lot of experimental methods have been brought forth to assess the dynamic character of the arc welding power source, but up to now, this issue has not been solved very well. In this paper, based on the fuzzy logic reasoning method, a dynamic character assessing model for the arc welding power source was established and used to analyze the dynamic character of the welding power source. Three different types of welding machine have been tested, and the characteristic information of the electrical signals such as re-striking arc voltage, low welding current and so on of the welding process were extracted accurately by using a self-developed welding dynamic arc wavelet analyzer. The experimental results indicate that this model can be used as a new assessing method for the dynamic character of the arc welding power source.
文摘A high frequency pulse power source for TIG welding is developed. The structure of two powers is adopted. The by pass circuit effectively eliminates the effect of the cable equivalent inductance. The maximum frequency of the output pulse current reaches to 16 kHz . The base current and the peak current can be regulated separately.
文摘This paper analyses the performance request of arc welding power source used in intelligent control of weld pool shape in pulsed GTAW, and develops a sample power source. The main circuit of the power source takes the structure of single ended inverter with two switches, and takes IGBTs as power switches. The working frequency of the inverter is set at 20 kHz. The control circuit takes PWM circuit as center, and uses single chip computer to complete the manage functions such as the control of working sequence, setting and changing of the welding parameters, sensing of the welding states and communication with outside computer etc. The dynamic reacting time of the whole power is 1 ms, the range of the output current is 5～250 A, the precision of the output current reaches to 1 A. The power strikes arc by contacting workpiece under 5 A, and have convenient interface with system computer. All above shows this power source is one with high performance.
文摘The full bridge zero voltage zero current switching （ FB-ZVZCS ） , which could adjust the output power by keeping the duty ratio of lagging leg constant and changing the duty ratio of leading leg, was a common circuit of soft switching arc welding inverter power source. However, when the duty ratio of leading leg was reduced to zero, the output power stayed the constant value instead of becoming zero. The working status and waveforms of some major parameters were studied in this paper while the duty ratio of leading leg was zero. It was concluded that the minimum output power of soft switching inverter was related to the charging voltage of paraUel capacitors, and the output power also could be reduced by reducing the duty ratio of lagging leg. A novel two-stage continuous PWM control method that could switch working-mode between full bridge and half bridge was put forward in this paper. This kind of control method could further reduce the output power of soft switching inverter in order to meet the requirement of low heat input of sheet metal welding.
基金This work is supported by the National Natural Science Foundation of China （No. 51207083）.
文摘The welding process essentially is a complicated nonlinear system with time-varying, uncertain, strong-coupling characteristics, so it is difficult to get high welding quality by traditional control approaches such as the standard proportionalintegral （ PI） algorithm. A new algorithm based on artificial neural network （ANN） is presented to achieve optimal P1 parameters and improve its adaptability. First, main parameters of artificial neural network are researched to improve the convergence rate and system stability. Then, six expert rules are proposed to constitute the expert adaptive ANN-PI algorithm. Experimental results show that the welding current control system＇has high dynamic response rate, and the welding process is stable.
