In recent years, the technical level of mechatronics of textile machinery has been continuously improved, and AC frequency conversion speed regulation has become a trend.Almost without exception, most newly developed textile machinery products use AC asynchronous motors with frequency conversion speed control devices.
AC frequency conversion speed regulation characteristics
I.Reduce power consumption and reduce costs
Textile mills are inseparable from air-conditioning equipment.When the air-conditioning motor is controlled by a frequency conversion governor, the power consumption is reduced and the electricity expenditure is greatly saved.According to data provided by a company, 12 air-conditioners can save more than 240,000 yuan in electricity throughout the year, and the electricity consumption of air-conditioners has decreased by an average of 6 or 7 percentage points.
II.Simplified mechanism and improved performance
PLC programmable controller or industrial computer control, and then through the frequency conversion governor to achieve synchronous and coordinated operation of multiple motors.The production process curve controls the movement of each mechanism, thereby simplifying the mechanism.For example, the roving machine uses AC frequency conversion to speed regulation, removes the cone wheel variable speed mechanism, and overcomes the problem of the cone wheel variable speed belt slipping and inaccurate variable speed.
For the spinning machine, the frequency conversion speed controller is used to remove the pause at the bottom of the peach and the impact at the top of the peach caused by the forming cam in the forming mechanism.Make the fine yarn roll in good shape.Unwinding at high speed in the next process.At the same time, a frequency conversion governor is used to control the variable speed of the thirty-nine main motor to control the number of revolutions of the spindle, so that the speed of the spinning yarn changes when the yarn is large, medium and small, in order to reduce the yarn breakage rate.
Application of AC frequency conversion technology
Inverter control of AC motors on textile machinery is mainly divided into two categories.One category is the commonly used Y series AC asynchronous motors.This kind of motor is mainly used in textile machines with low speed regulation accuracy requirements and small speed regulation range.The other is a special asynchronous motor for AC frequency conversion and speed regulation.It is mainly used on machines with high speed regulation accuracy requirements and wide speed regulation range.
The following describes the different forms of frequency converters.
1) Open-loop control of asynchronous motor speed regulation with frequency converter is called V/F form.The circuit in this way is simple and reliable.However, the speed regulation range is within the range of 10:1, the speed regulation accuracy is 2% to 5% lower, and the low-speed performance is not ideal.It is mostly used in knitting machines or less demanding textile machinery.
2) The cool Horse A900 series inverter is used, which has excellent low-speed characteristics.The circuit structure is simple and the reliability is high.At the same time, it has good acceleration and deceleration characteristics, torque characteristics and current limiting characteristics.The speed regulation accuracy can reach 0.5% to 1%.The speed regulation range is within the range of 20:1.It is more suitable for speed regulation of printing and dyeing machinery.
On some equipment, all electrical components and frequency converters, control panels and mechanical parts of the winding head are integrated into one, which reduces the volume and enhances reliability.
Application of pendulum frequency function of upconverter with elastic false twisting machine
In order to make the formed spindles without bulging and flat on the elastic false twisting machine, the pendulum frequency function must be added to the groove motor.The Cool Horse Q9000 series inverter has built-in pendulum frequency function software, which can solve this problem well.
Small and medium-sized elastic twisting machines are the main equipment for the production of man-made fiber elastic silk threads. There are nearly 10 textile machinery factories in China that produce such equipment, and there is a very broad market in developed coastal areas.At present, there are two main sources of 120 ingots and 144 ingots available on the market. From the control point of view, the two control principles are exactly the same. This only introduces the control method of 120 ingots.
Process characteristics of elastic fake twisting machine
The 120 man-made fiber silk threads are divided into two groups, each group of 60, and the traction force of the roller 1 makes 60 spindles free to release the thread.
After the heating, false twisting, and reheating process, the roller 2 is towed to the next process. After the false twisting yarn is oiled, the yarn is wound into 120 spindles that are most conducive to the release movement, providing high-quality semi-finished products for subsequent deep processing.
Basic control requirements
●Roller 1, false twist, roller 2, refueling, slot cylinder, black cylinder motor must ensure synchronous operation, and the proportion is adjustable.
●Maximum speed: 550m/min
●There can be no doffing at both ends of the finished spindles, and the surface cannot be bulged, so it is as flat as one.
●24-hour continuous work system.
Control features
●All 10 motors use 380V three-phase asynchronous motors, all of which are driven by Cool Horse A900 series frequency converters, which match the same power one by one.
●The synchronous control signal is provided proportionally by the synchronous controller, and the internal signal superposition function of the inverter is fine-tuned on-site.Signal superposition can be absolute superposition or relative superposition.
●In order to make the forming spindle without bulging and flat as one, the pendulum frequency function must be added to the groove motor.Cool Horse A900 series inverter already has built-in pendulum frequency function software, which can solve this problem well.
Pendulum frequency function description
The spindle forming process is formed by the superposition of two independent movements.A constant speed (constantspeed) rotational movement, a reciprocating (Traverse) movement.The two movements are superimposed, and the surface of the yarn paper tube forms a diamond-shaped mesh trajectory.If the two movements are both at uniform speed, a drum kit will be formed at the intersection of the yarns, as shown in the without pendulum frequency function (Without Wobble).If you want to disrupt the intersection of each layer and change the speed of reciprocating motion from time to time, that is, increase the pendulum frequency function, then this problem will be successfully solved.
The built-in seven-stage automatic operation function of the unwinding upconverter of the elastic fake twisting machine is applied to the built-in seven-stage speed adjustment of the cool horse A900 series inverter. Each speed can be controlled in the forward and reverse directions, and the acceleration and deceleration time is adjustable.
