Study On The Parallel Current-Sharing Technique Of High Frequercy Switch Power Supply

Nowadays the technology of switching power supply is gradually being perfect. However, there is no end to the demand for a high-power, high performance power supply. The technique of parallel current-sharing is a tendency of the power electronics, through the module in parallel can well satisfy the need of high-power supply on characteristic, capacity, weight, volume, efficiency and reliability.Many sets of power formed in parallel constitute the high-power power system, which should be like single power. In case of import buses and export load changing, the system should remain long-period and faultless performance except that such electric characteristics as the systematic voltage of output, etc. remains stable and does not change all the time. The general principle of the parallel current sharing and all kinds of current sharing technology of power parallel running are introduced in the paper. The main factors that influence transient characteristic and steady-state characteristic of outputting impedance method parallel system have been discussed in detail. The main control strategies to improve the steady-state characteristic of outputting impedance method parallel system have been summarized and the weak points of non-linear outputting impedance method have also been pointed out. A kind of self-adaptation and closed loop outputting impedance method has been put forward on this basis.The maximum current automatic current-sharing method has also been discussed in detail in the paper. According to the features of the maximum current-sharing method, the small-signal analysis method has been utilized and the features of three-loop control have been disclosed and the design principle of three loops has been proposed. This rule is favorable to the stability of the whole system, and it has realistic meanings.