Two-stage isolated dc/ac conversion circuit structure

A two-stage isolated DC/AC conversion circuit structure, comprising:

• a DC power supply;
• a waveform generation circuit connected in parallel with the DC power supply, having an inductor and a main switch, the main switch controlled by a controller, showing conduction and cut-off, utilizing a cycle of conduction and cut-off to control a charge and discharge time of the DC power supply to the inductor, the result being to gradually increase and reduce the charge and discharge time, allowing for gradually increasing and reducing potentials, and the potentials converting the DC wave from the DC power supply into a rarefaction wave power with positive half wave;
• an energy storage circuit connected in parallel with the waveform generation circuit, having a capacitor with low capacity and a diode for preventing inversion, the capacitor able to be converted into the rarefaction wave power for energy storage and filtering out high-frequency waves of the rarefaction wave and remaining positive half wave power with low-frequency;
• a first switch circuit connected in parallel with the energy storage circuit, having a first transformer and a first switch, the first switch connected with a primary side of the first transformer;
• a second switch circuit connected in parallel with the first switch circuit, having a second transformer and a second switch, the second switch connected with a primary side of the second transformer;
• a first isolation circuit having a first diode for preventing output inversion, connected with a secondary side of the first transformer and connected in parallel with an end user;
• a second isolation circuit having a second diode for preventing output inversion, connected with a secondary side of the second transformer and connected in parallel with the end user:
• allowing the first, second switches and the main switch to be controlled by the controller and another controller and showing operating mode 1:
• the main switch conducts, the first switch conducts, the second switch is cut off, and the main switch conducts, the first switch is cut off, the second switch conducts, which allows positive half wave power with low-frequency stored in the capacitor after filtering, respectively to be boosted through the first and second transformers, and then to be rectified through the first and second diodes, outputting positive and negative half-wave AC power to the end user, so that the end user obtains full-wave AC power, then, the first, second and the main switches controlled by the controller and another controller and presenting operating mode 2:
• the main switch is cut off, the first switch conducts, the second switch is cut off, and the main switch is cut off, the first switch is cut off, the second switch conducts, which allows the DC power supply to be converted as a rarefaction wave power through the inductor charging and discharging, forming low-frequency sine wave power after the capacitor filtering, then the low-frequency sine wave power recharges the capacitor, after recharging, the low frequency half sine wave power is respectively boosted through the first and second transformers, and then is rectified through the first and second diodes, outputting positive and negative half-wave AC power to the end user, so that the end user obtains full-wave AC power, likewise, the operating mode 1 and 2 are repeated constantly, and the end user promptly acquires AC power converted from DC power supply.