Methods to improve the problem of excessive temperature rise of switching power supply transformer
In practical applications, excessive temperature rise often occurs in two aspects: the MOS tube of the power transformer and the transformer design itself. Today we will start from these two aspects to see how to effectively solve the excessive temperature rise of the switching power supply transformer. High question.
In practical applications, excessive temperature rise often occurs in two aspects: the MOS tube of the power transformer and the transformer design itself. Today we will start from these two aspects to see how to effectively solve the excessive temperature rise of the switching power supply transformer. High question.
First of all, from the perspective of the transformer itself, once the temperature rise is too high and it becomes hot, it is mainly caused by four problems, namely copper loss, winding process problems, transformer iron loss and the transformer design power is too small. No-load heating occurs when the transformer insulation is broken or the input voltage of the transformer is high. If the insulation is broken, the coil needs to be re-wound. If the input voltage is high, the input voltage needs to be reduced or the number of coil turns needs to be increased. If the voltage is normal and it gets hot under load, it means that the load of the power transformer is too large and its load design needs to be changed.
In the design process of the switching power supply transformer, the heating situation of the MOS tube is the most serious, and its own problem of excessive temperature rise is caused by losses. The loss of MOS tube is composed of switching process loss and on-state loss. To reduce on-state loss, you can reduce on-state loss by selecting a switching tube with low on-state resistance. Switching process loss is caused by the gate charge size and switching time. To reduce the loss in the switching process, you can choose devices with faster switching speed and shorter recovery time. But what is more important is to reduce losses by designing better control methods and buffering technologies. For example, using soft switching technology can greatly reduce this loss.
In addition, there is another possibility that will cause the temperature rise of the power transformer itself to be too high, that is, the transformer itself is aging. When engineers check the transformer itself and the MOS tube and find no abnormalities, they need to make a comprehensive judgment based on the working time and working life of the transformer.
