Induction cooker is always burning insurance, what's the matter?
Reason four: abnormal working voltage of 18VIn the induction cooker, when the 18V operating voltage is abnormal, the IGBT tube excitation circuit, the fan cooling system and the LM339 work will be abnormal, resulting in an instant damage to the IGBT tube.
Reason three: synchronous circuit abnormalitiesThe main function of the synchronous circuit in the induction cooker is to ensure that the switching pulse front of the G pole added to the IGBT tube is synchronized with the VCE pulse on the IGBT tube. When the synchronization circuit is abnormal, the IGBT tube is instantly damaged by breakdown.
Reason two: IGBT tube excitation circuit exceptionThe pulse signal output by the oscillating circuit cannot directly control IGBT saturation, conduction deadline, must pass the excitation circuit of pulse signal amplification to complete, if the problems of excitation circuit, high voltage will be added to the IGBT tube G, IGBT pipe leads to instantaneous breakdown, common drive tube S8050, S8550 joint damage.
In the maintenance of induction cooker, the damage to the power tube occupies a large proportion. If there is no identification of the cause of the fault, the pipe will be replaced hastily, which will cause further damage. Eight major causes of damage to power tubes:One reason: 0.3uf/1200v resonant capacitor, 5uf/400v filter damage or insufficient capacity.In the electromagnetic oven, if 0.3uf resonant capacitor 5uF filter capacitor capacity becomes small, failure or poor characteristics, will cause the LC oscillation circuit of high frequency electromagnetic oven, thereby causing damage to the IGBT tube, the other circuit without exception, must be replaced together the two capacitors.
Reason five: abnormal heat dissipation systemInduction cooker operating in high current status, its calorific value, if the cooling system failure, will lead to overheating of the IGBT pipe damage.Reason six: single chip microcomputer abnormalSCM internal abnormalities will be due to abnormal frequency of work and burned IGBT tubeReason seven: VCE detection circuit abnormalitiesVCE detecting circuit of the pulse voltage of IGBT tube collector through the resistor divider, sampling the sampling voltage, the voltage change information to give CPU, CPU changes the voltage monitoring, a variety of corresponding instructions, when the VCE detects abnormal circuit, VCE pulse amplitude value exceeds the limit value of IGBT, resulting in IGBT the damage
