Digitalized double-excitation uninterrupted switching power supply

A digitalized double-excitation uninterrupted switching power supply, comprising:

• a main transformer, provided with a primary coil and a secondary coil;
• a main loop, comprising a high-voltage switching network connected between a high-voltage direct-current bus and a high-voltage ground, and a resonant inductor, the primary coil and a resonant capacitor connected from a first end to a second end of the high-voltage switching network in sequence;
• a synchronous rectification output loop, comprising a current-doubler rectifier formed by connecting two synchronous rectifier tubes in series oppositely and the secondary coil in parallel, and a filter circuit connected to a first output end and a second output end (E1 and E2) of the current-doubler rectifier;
• a synchronous direct-current converting circuit, comprising a low-voltage switching tube, an isolator and a low-voltage direct-current power supply connected between the first output end (E1) and the low-voltage ground in sequence;
• and another low-voltage switching tube connected between the second output, end (E2) and a negative electrode of the isolator;
• and
• a digital center control unit, providing two groups of synchronous drive pulses, wherein the first group of drive pulses DrH′ and DrL′ controls the high-voltage switching network, and the second group of drive pulses DrH and DrL controls the two synchronous rectifier tubes and the two low-voltage switching tubes;
• a first sampling input end of the digital center control unit is connected with an output end of the synchronous rectification output loop, a second sampling input end of the digital center control unit is connected with an isolated sampling unit which is used, for sampling the voltage of the high-voltage direct-current bus and automatically selecting the main loop to work according to the voltage change;
• wherein when the voltage between the high-voltage direct-current bus and the high-voltage ground is rated voltage, the main loop provides electric energy for loads by the synchronous rectification output loop;
• when the voltage between the high-voltage direct-current bus and the high-voltage ground is 95%-85% of the rated voltage, the main loop provides electric energy for the loads alternatively;
• and
• when the voltage between the high-voltage direct-current bus and the high-voltage ground is lower than 85% of the rated voltage the main loop provides all electric energy for the loads.