The Research Of Intelligent Control Power For Full Bridge Soft-Switching

With the development of the communication techniques, the low voltage/large current DC-DC converters are used more and more widely. PWM soft-switching technique is proposed to make converter operate with high efficiency in higher frequency, which has attracted increased attention in the field of power electronics. therefore, phase-shift zero-voltage and zero-current-switching(ZVZCS) full bridge PWM DC-DC converter is researched in this paper, and the design and research of intelligent control systems for soft switch power were implemented.Combining fuzzy control and soft-switching operating principle, realization methods of zero-voltage switching for leading leg and zero-current switching for lagging leg are researched synthetically. After comparing some typical ZVZCS full bridge PWM DC-DC converters, the advantage and disadvantage are summarized. Then an improved ZVZCS full bridge DC-DC converter with passive voltage clamping is proposed the operating principle and soft-switching condition of the proposed converter is analyzed in detail. This has many advantages, such as widening the load range for soft switching, decreasing additional losses for auxiliary resonant circuit and reducing stress of the voltage and current for the switches. On the base of the theoretical analysis, the design of the system for the intelligent control power is carried out.In order to maintain the precision of output DC current, this dissertation designs a fuzzy-PID controller, which combines the agility of fuzzy controller with the high precision of PID controller, and increases the control function of loop control.Finally, simulations are done for the digital fuzzy PID PWM control method. The theory analysis and simulation meet each other very well. That shows the technology of intelligent control plays a key role in the full bridge soft-switching power, and the system has good control efficiency.