Improvement Methods for the Problem of Excessive Temperature Rise in Switching Power Transformers
In practical applications, high temperature rise often occurs in both the MOS transistor of the power transformer and the transformer design itself. Today, we will start from these two aspects to see how to effectively solve the problem of high temperature rise in switching power transformers.
In practical applications, high temperature rise often occurs in both the MOS transistor of the power transformer and the transformer design itself. Today, we will start from these two aspects to see how to effectively solve the problem of high temperature rise in switching power transformers.
Firstly, from the perspective of the transformer itself, once the temperature rise is too high and the heat is generated, it is mainly caused by four problems: copper loss, winding process issues, transformer iron loss, and transformer design power being too low. No-load heating refers to the insulation of the transformer being damaged or the input voltage of the transformer being high. 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 coils needs to be increased. If the voltage is normal and generates heat and heat with load, it means that the load of the power transformer is too large and the load design needs to be changed.
In the design process of switching power transformers, the heating of MOS tubes is the most severe, and the problem of excessive temperature rise itself is caused by losses. The loss of MOS transistors consists of two parts: switching process loss and on state loss. Reducing on state loss can be achieved by selecting switch transistors with low on state resistance. Switching process loss is caused by the size of gate charges and switching time. To reduce switching process loss, devices with faster switching speed and shorter recovery time can be selected to reduce it. But more importantly, it is important to reduce losses by designing better control methods and buffering techniques, such as using soft switching technology, which can greatly reduce such losses.
In addition, there is another possibility that the temperature rise of the power transformer itself may be too high, which is the aging phenomenon of the transformer itself. When the engineer checks the transformer itself and the MOS transistor and finds no abnormalities, a comprehensive judgment needs to be made based on the working time and lifespan of the transformer.
