The role of switching power transformer
The switching power supply transformer is a power transformer with switching tubes added. In the circuit, in addition to the voltage conversion function of the ordinary transformer, the switching power supply transformer also has the functions of insulation isolation and power transmission. Switching power supply transformers are generally used in occasions involving high-frequency circuits such as switching power supplies.
The switching power supply transformer and the switching tube together form a self-excited (or other excited) intermittent oscillator, thereby modulating the input DC voltage into a high-frequency pulse voltage.
It plays the role of energy transfer and conversion. In the flyback circuit, when the switch tube is turned on, the transformer converts the electric energy into magnetic field energy and stores it, and releases it when the switch tube is turned off. In the forward circuit, when the switch When the switch is turned on, the input voltage is directly supplied to the load and the energy is stored in the energy storage inductance. When the switch is turned off, the energy storage inductance is used to transfer the freewheeling flow to the load.
Convert the input DC voltage into various low voltages required.
Classification of switching power supply transformers
Switching power supply transformers are divided into single-excitation switching power supply transformers and double-excitation switching power supply transformers. The working principles and structures of the two switching power supply transformers are not the same. The input voltage of the single-excitation switching power supply transformer is a unipolar pulse, and it is also divided into forward and reverse voltage output; while the input voltage of the double-excitation switching power supply transformer is a bipolar pulse, generally a bipolar pulse voltage output.
Characteristic parameters of switching power supply transformer
Voltage ratio: refers to the ratio of the primary voltage to the secondary voltage of the transformer.
DC resistance: that is, copper resistance.
Efficiency: output power/input power*100[%]
Insulation resistance: the insulation capacity between the windings of the transformer and between the cores.
Dielectric strength: The degree to which the transformer can withstand the specified voltage within 1 second or 1 minute.
