The Research On Hot Swap Technology Of Power Supply

The hot swap technique is a key technique that achieves the continuous operation and uninterrupted maintenance. It is a practical way that improves the stability of the power supply system with redundant backup for the key parts in the power supply and the replacement of the fault power supply and power enhancement in the uninterrupted condition. Thus, more and more attention is attracted by the technique. The hot swap function is very important in the process of the power supply design. The hot swap function is required in order to facilitate the non-shutdown time in the application of the power supply architecture with the fault tolerance. It needs to be avoided that the current and voltage is rippled seriously during the process of the hot swap.Firstly, the topology of the DC/DC converter is introduced, then establishes a parallel operation model for Buck DC/DC converter, analyses the reasons for the cause of the unbalance output current and the factors that lead to the unbalance condition according to State-Space Averaging Method. The control strategy of the DC/DC converter is composed of two loops which is a current loop and a voltage loop. The conventional PI controller is used as the controller. The current share method is the maximum automatic current-sharing method.Secondly, the hot swap controller is set up on the base of the DC/DC converter, introduce the design method of the controller and several key problems about hot swap connectors. It is mainly introduced that the suppression method about the current and voltage falling and rising, moreover establish a simulation model with Saber, then build up the hardware circuit. The digital signal processor TMS320F28335 is used as the control center, the peripheral circuits includes a main controller circuit, a power circuit, a detection circuit, a protection circuit and a driving circuit. The program is realized in a modular design method. The programs are composed of the main program and the interruption subroutines. The main function is completed by the subroutines and includes the voltage detection, the timing function and the analog switch drive.Finally, the hardware circuit is set up, the current and voltage of the converters is sampled. It results that the current is shared by the converters equally, the ripple of the voltage is decreased seriously. Thus, the method is effective and practical.