Solid State Hf Welder for ERW Welded Pipe Line

• Customization: Available
• Cooling Way: Water Cooling
• Control: Automatic
• Model NO.: 200KW
• Style: Vertical
• Frequency Range: High Frequency
• Electric Current: DC
• Transport Package: Plywood Case
• Specification: 150KW
• Trademark: Brilliance Machinery
• Origin: China
• Production Capacity: 100 Sets

Product Description

Product Description

Besides the traditional solid state high frequency welder, our company has successfully developed new type of high power factor rectification technique for new generation solid state HF welder. The three-phase full-bridge rectifier circuit composed of six thyristors is stable and reliable. Most of the existing solid-state high-frequency circuits in China adopt this technology, and it is widely used in the welding of steel pipes and aluminum bars. However, there are also disadvantages of low power factor and serious harmonic pollution.
Because of silicon controlled rectifier device adopts the phase shifting control, power regulation is by changing the trigger angle and voltage regulation, circuit from the grid to absorb the sine wave is lack of angle, and leave the grid is also part of the sine wave, obviously in the left part contains a large number of harmonics, at the same time because of different voltage and current phase, resulting in low power factor, the lower the DC output voltage, The lower the power factor).
The theoretical calculation and test show that when the trigger Angle of the three-phase fully controlled rectifier bridge is 0, or the uncontrollable bridge composed of diodes is used for rectifier, the harmonic generated by the bridge is very small and the power factor is very high (more than 0.9). However, in practice, continuous DC voltage regulation (that is, output power regulation) is required, and the HF welder cannot always be working at full voltage condition. In order to make the induction welder have the minimum harmonic, the highest power factor, and the output power adjustable function, we must add additional voltage regulating device behind the uncontrollable rectifier bridge, that is, separate the rectifier and voltage regulating.

Three-phase power frequency of the three-phase uncontrolled consisting of alternating current (AC)through the diode bridge rectifier bridge into DC, and flat DC voltage generated by the large capacitor filter group, theh adopt high power switch module IGBT to realize on-off control. In the case of constant switch frequency, by adjusting the percentage of time of on-off, we can control the output DC voltage average value. This is pulse width modulation technology (for short as PWM or chopper technology). PWM chopper modulation generated width variable pulse DC, through reactance or capacitor filtering, can provide to the load with fast, stable and adjustable DC voltage and current.

Product Parameters

Comparison of SCR HF welder & high power factor HF welder

Comparison parameters	Silicon controlled rectifier	High power factor HF welder
Controlled device	Controlled SCR	IGBT
Working frequency	300HZ	12~14KHZ
Control mode	Phase shift trigger	PWM modulation
The output DC	Lack of angle, half wave	High density DC square wave
300HZ voltage ripple component	8%~30%	<2%
Control time constant and control effect	3.3 milliseconds,control effect not smooth	75 microsecond, control effect is smooth and stable
Voltage regulation accuracy	<5%	<1%
Accuracy of steady flow	<5%	<1%
Cooling way	Water cooled	Water cooled
Efficiency of AC-DC	<90%,reactive power loss is big	93%
Power factor	Change between0~0.9,usually around 0.75~0.8	The range can reach 0.92
Non work current on the net side	Big	small
Capacity utilization of user power supply	70%~80%	90%
The user's power factor compensation capacitor	Need to be	Don't need
Welding temperature control & effect	The temperature fluctuates greatly, the weld quality is slightly worse	The temperature fluctuation is small, the weld quality is pefect
The input voltage allows the range of fluctuation	±10%	±20%
Power grid interference	Big , not easy to eliminate	Small, easy to eliminate
Failure protection speed	Slower, milliseconds	Extremely fast, microseconds
Energy saving effect	Good	Better

 

Our Advantages

The advantages of the solid state high frequency welder using PWM technology: 

1. High power factor: If the power factor is greater than or equal to 0.92, no power compensation device is required.
2. Low harmonic pollution: generally, there is no need to add additional harmonic processing equipment.
3. Stable output power: output ripple is less than 0.2%, so the burr of welded pipe is more uniform.
4. Fast protection: interlocking protection time ≤10uS. The device is more reliable.
5. High power efficiency: Because the reduction of reactive power loss, the efficiency of the whole machine has been improved.
It should be noted that the high power factor DC HF welder produced by our company is different from other manufacturers. The rectifier part does not use uncontrollable diode, but still uses silicon controlled. When working normally, the SCR works in the full conduction state, the same as the diode, and once there is a fault, it can be quickly turned off, which is much faster than just cutting off the contactor or air switch, thus improving the reliability of solid state high-frequency welder.

 

Installation Instructions

One set complete of solid state hf welder is generally composed of the following parts: power distribution cabinet, step-down tranformer, rectifying cabinet, inverter cabinet, water cooling system, DC speed control cabinet, operation table. The site layout can be referenced as follows:

Environmental requirements:
The solid state hf welder is designed for indoor installation to avoid rain, frost and sunshine. The following conditions should also be met:
1.The altitude is not more than 1000 meters. If the altitude is too high, the cooling effect will become worse due to the reduction of air pressure
2. Ambient temperature -5ºC~+40ºC (lower than 0ºC, attention should be paid to prevent freezing and damage to cooling water pipeline after shutdown)
3. The relative humidity of the air shall not exceed 85%
4. No conductive explosion dust, no corrosive metal and insulation damage gas and steam
5. No violent vibration and shock
If the above conditions are not met, customers advise us when placing the order. Our company will consider that during the machine designing.