Improvement method for excessive temperature rise of switching power supply transformer
In the actual application process, the excessive temperature rise often occurs in 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 temperature rise of the switching power supply transformer. high question.
In the actual application process, the excessive temperature rise often occurs in 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 temperature rise of the switching power supply transformer. high question.
First of all, from the perspective of the transformer itself, once the temperature rises too high and generates heat, it is mainly caused by four problems, namely copper loss, winding process problems, transformer iron loss, and transformer design power is too small. No-load heating is caused by broken insulation of the transformer or high input voltage of the transformer. If the insulation is damaged, the coil needs to be rewound. If the input voltage is high, the input voltage needs to be reduced or the number of coil turns should be increased. If the voltage is normal, but it becomes hot when the load is on, 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 switching power supply transformers, the heat generation of MOS tubes is the most serious, and the problem of excessive temperature rise is caused by losses. The loss of the MOS tube is composed of two parts: the switching process loss and the on-state loss. To reduce the on-state loss, the on-state loss can be reduced by selecting a switch tube with low on-state resistance. The switching process loss is caused by the gate charge and the switching time. Yes, reducing the switching process loss can be reduced by selecting devices with faster switching speed and shorter recovery time. But what is more important is to reduce the loss by designing a better control method and buffer technology, such as using soft switching technology, which can greatly reduce this loss.
In addition, there is another possibility that the temperature rise of the power transformer itself will be too high, that is, the transformer itself is aging. When the engineer checks the transformer itself and the MOS tube and finds no abnormalities, it is necessary to make a comprehensive judgment based on the working time and working life of the transformer.
