The duty cycle of flyback switching power supply is mainly determined by the input voltage and withstand voltage of switching power supply tube. When the input voltage changes, the duty cycle also changes. For example, when the input voltage is AC260V and the switching tube voltage is 650V, the duty cycle is 0.306; When the input voltage is AC170V, the duty cycle is about 0.5. When the input voltage is lower than AC170V, the duty cycle is greater than 0.5. However, regardless of such changes in the input voltage, the switching power supply will be large enough to stabilize (or change) the value of the output voltage by changing the duty cycle.

500kw load bank

What is the main difference between forward and back excitation?

The forward switching AC power supply is the power supply of the switching tube. The power supply is responsible for providing power output and disconnecting when there is no power output. Flyback switch AC power supply is just the opposite, the power switch tube only stores energy to the transformer when conducting, does not provide power output to the load, only when the power switch tube is closed to provide output to the load. The output voltage of the forward switching AC power supply is the average of the rectifier output voltage, and the output voltage of the flyback switching AC power supply is the half-wave average of the rectifier output voltage. The phases of the two voltage outputs are completely opposite.