Research On The Main Circuit Of High-power Switch Mode Power Supply

High-power Switch Mode Power Supply (SMPS) which is in demand more and more is widely employed in many fields, such as electrochemistry, vacuum sputtering and metalling, DC motor velocity control, welding and cutting and so on. Power electronics, control theory, soft-swtich technology and synchronous rectification provide important guarantee for the continuous development of high power SMPS. Computer simulation technology plays an important role in the architecture design and parameters optimization of the SMPS, it can reduce the cost, shorten the design cycles and improve the product reliability. Based on the development situation at home and abroad, the paper researched and analyzed on the main topology of the SMPS that running in the condition of high power and large current, and proposed a feasible solution. Then the closed-loop system was simulated correctly by Saber.In this paper, influence brought by cutting the large-capacity electrolytic capacitors that connected to the bus line and the feasibility of only the noninductive capacitors connected to the bus line was analyzed; the paper described the operation principle and various control methods of the full bridge inverter, also the factors that could make switches realize the soft-swithing were analyzed, then the paper proposed a new strategy that could make the IGBT realize the ZVS by comparing exsiting soft-switch technologies; the paper selected the combination of"serious in the primary, paralle in the secondary"to be the transformer structure, whose feature of automatic load sharing was described in detail, influence of the leakage inductance to the system was analyzed, also main causes and suppression methods of the DC magnetic bias were researched, then a new strategy to solve the above issues was proposed; doubler rectifier topology was selected in the output circuit, the basic principle of synchronous rectification and synchronous rectifier MOSFET's main features were described, and based on the proposed control method of full bridge inverter, the control strategy to realize the MOSFETs'ZVS was proposed in the paper.The system rated 12V/5000A was designed, the main devices were modeled, the parameters were calculated, and the digital controller was built, then the system was modeled and simulated overally, the results showed that the proposed scheme was available, and it could provide an important reference to the SMPS design of high power and large current.