Research On Cable Extrusion Molding Machine Heating Device Based On The Principle Of Induction Cooker

Resistance wire and coil are adopted by the traditional cable plastic extruder for heating. This heating method conducts by heat transmitting, with low heat energy utilization rate, great loss, short service life and regular maintenance needed. Therefore, a kind of cable plastic extruder heating device based on the principle of electromagnetic oven is developed in this paper. The defects of the existing heating method are overcome and heating performance is improved.In this paper, the electromagnetic heating principle of electromagnetic oven is first introduced and cable extruder electromagnetic heating device is designed on the basis of the structure of the electromagnetic oven. The power frequency 220V AC is directly used as the DC-side power supply of the heating coil after rectifying and filtering, and a single IGBT is used to control the charging and discharging of the heating coil. Eddying effect is generated to complete the heating function in the process of charging and discharging of the heating coil. Taking into account the IGBT operating at high voltage and high current state, a more perfect IGBT protection scheme is designed, including hardware protection and software protection. Hardware protection includes collector voltage over-voltage protection, surge current over current protection; software protection includes IGBT temperature protection and power grid voltage over-voltage protection. In this device, AVR microcontroller Atmega16 is used as the control core; the sensor circuits of temperature, current and voltage are extended; the data collection of IGBT temperature, material temperature, power grid voltage and current is completed; the performance of data monitoring and software protection is realized. Constant temperature control for material temperature is needed in the process of heating cable plastic extruder. Therefore, the PID control algorithm is applied to the material constant temperature control. PWM signal duty ratio of IGBT drive circuit is dynamically adjusted according to material temperature and material temperature is maintained near the set value.The developed electromagnetic heating device prototype is applied to cable plastic extruder, and the performance test and experiment observation are carried out. Test results show that the device works reliably. Compared with some parameters of the traditional heating method, it is proved that the electromagnetic heating device can save the electric energy and improve the heating performance.