Clutch motor is the most commonly used motor in the process of industrial sewing machine application. The obvious characteristics of this kind of motor are very high energy consumption and noise. In addition, the temperature rise is relatively obvious. In order to better improve the energy-saving efficiency of industrial sewing machine operation and enhance its intelligent application effect, an energy-saving controller is developed, which can save energy. The controller can effectively ensure that the reactive power consumption of the power system can be reduced to a reasonable state under the condition of smooth operation of the motor, and thus the efficiency of production can be significantly improved. Industrial sewing machines are more suitable for large-scale centralized production and sewing work in the industrial sector, usually using the form of motor drive. Clutch motors are the most commonly used form of motor in sewing machines. The cost of this kind of motor is not very high, so there has been no very good substitute for a long time, but there are also some deficiencies, among which the most obvious one is the motor sewing machine. It is the insufficiency of energy consumption and the relatively low efficiency, which also hinders the energy-saving transformation.
With the development of electronic information technology, motor energy-saving has a very broad prospect. Clutch motor is a common form of motor in industrial sewing machine. It uses single-phase asynchronous motor, that is, single-phase power supply for power supply processing. It is regarded as a kind of asynchronous motor for driving. The single winding of the stator of this motor generates pulsating magnetic potential, and the positive and reverse rotating magnetic potential obtained in decomposition is exactly the same. The single-winding asynchronous motor does not start the torque in the process of operation, but after the rotor rotates, although the stator is only electrified by the single-winding, the motor can generate driving torque in this process, so that the motor can ensure normal operation in the case of single-winding. In the past, the power of clutch motor was mainly transmitted by clutch clutch interaction. Whether it was in the sewing task or not, the motor was always in the running state, so the idle time of the motor was sometimes longer than the working time, so the consumption under the idle state was also very large. Generally, the output efficiency was only 40% – 50% of the input power, and the motor was always in the running state. In the working state, regardless of the thickness of the material sewn. It has always been in the state of full power output. When the sewing machine is waiting for material, the motor mainly adjusts the load problem through clutch and carries out continuous no-load operation, which makes the sewing opportunity produce very serious standby loss phenomenon. In the actual work of the motor, the nominal size is too large, and the operation cycle is in a long-term change, thermostatic element so that there will be very serious vibration in the operation of the motor, and the efficiency of the machine operation can not be guaranteed. On the one hand, a lot of power will be wasted, but also the time of failure downtime will be greatly increased, so that the performance and life of the motor itself are not guaranteed to a certain extent. Profit impact. In the process of equipment maintenance, it also needs to consume more expenses. We have developed an efficient energy-saving motor controller to control single-phase asynchronous motors with efficiency of 70-80%. This controller can greatly reduce the reactive power consumption of power system under the condition of motor operation. Changing the high power of industrial sewing machine motor in the original state, intelligently reducing the no-load power (without affecting the use effect), reducing the temperature of motor by 15 ~32 C (measured), reducing the high-temperature aging of motor coil, prolonging the service life, effectively reducing the vibration level, shortening the fault shutdown time and reducing the wear and tear.
It can ensure the motor start smoothly and continuously, eliminating the mechanical impact and large starting current caused by the conventional starting mode. It can be popularized and applied in the field of industrial sewing machine by replacing AC clutch motor with high-efficiency and energy-saving single-phase asynchronous motor.
Under no-load condition, the electricity-saving rate can reach 50-70%, while under load condition (fabric sewing), the electricity-saving rate can still reach 10%. ~ 25%. After installing the energy-saving controller of industrial sewing machine, the average power-saving can reach 30%-50%. Fig. 1 shows the hardware structure of the system. The power supply provides the required voltage or current for the power conversion circuit by rectifying and filtering.
The power conversion circuit mainly plays the role of power driver to drive the single-phase asynchronous motor M. The speed of the motor is measured by the speed sensor E and then transmitted to the control circuit through A/D conversion. The control circuit is the brain of the whole controller system. It controls the work of the whole device and realizes the corresponding protection function. Generally speaking, the control circuit has the following functions: control pulse generation circuit, drive circuit, voltage feedback control circuit, various protection circuits, display circuit, auxiliary power supply circuit, etc. The control circuit is the control core of the system. According to the set requirements, other parts of the control system work orderly. At the same time, the speed of the motor is accurately controlled by power conversion and the working condition of the motor is tested. It also has the function of voltage and current detection. It can control various starting modes. As shown in Fig. 2, the system control schematic diagram is designed to design the current loop in the system to control the variation of the motor current.
This will not only reduce the pulsation of the torque, but also prevent overload current and damage the system when the motor is started rapidly. In order to make the current loop and speed loop play their respective roles, the current regulator and speed regulator are set respectively in the system. The inner ring is a current loop and the outer ring is a speed loop. The current controller is in the form of proportional integral differential (PID) controller, and the speed controller is in the form of intelligent control-fuzzy controller. The comprehensive effect of the control is good and the robustness is strong. The influence of disturbance and parameter change on the control effect is greatly weakened, which is suitable for the control of the speed regulating system of sewing machine. In the process of single-phase asynchronous motor control, the efficiency of the high-efficiency energy-saving controller is relatively high, even more than 80%. There are embedded software in the control system. The system can detect the operation status of the click itself at any time in the process of operation. The system needs to detect the actual operation status of the motor frequently in the process of operation. In addition, it also needs to test the actual operation status of the motor comprehensively. The information is transmitted to the embedded control system in time, and the output speed and power of the click are adjusted by professional software, so that the motor is in the state of energy saving in the process of working. When the sewing machine is in a standby and standby state, the system should be suspended so as not to cause standby loss. Under light load, the main component of stator excitation current is reactive current, and the power factor is very low, about 0.1-0.2. On the premise of given speed, the reactive power component of stator current can be effectively reduced and the power factor can be improved by reducing the voltage appropriately. In full load operation, the voltage is changed according to the load torque requirement at a given speed to avoid excessive stator excitation reactive current and obtain a higher power factor operation state. This controller can greatly reduce the reactive power consumption of the power system when the motor is running.
The developed energy saving controller not only saves energy, but also significantly reduces costs and reduces environmental pollution, which is of great significance for promoting the development of sewing machinery industry and improving the market competitiveness of the entire sewing machine in China. In order to improve the competitiveness of China’s industrial sewing machine industry and win the initiative for the international competition of enterprises, we should intensify the research and development of science and technology, vigorously carry out the research and development of high-end products with high technology content, high added value and independent intellectual property rights.