• Journal of Power Electronics
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• 제17권3호
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• pp.632-640
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• 2017

Input series output independent (ISOI) dc-dc converter systems are suitable for high voltage input and multiple output applications with low voltage rating switches. This paper proposes a novel control strategy consisting of one output voltage regulating (OVR) control loop and n-1 (n is the number of modules in the ISOI system) input voltage sharing (IVS) control loops. An ISOI system with the proposed control strategy can be applied to applications where the output loads of each module are the same. Under these conditions, IVS can be achieved and output voltages copying can be realized in an ISOI system. In this control strategy there is only one controller for each module and the design process of the control loops is simple. Since no central controller is needed in the system, modularity of the system is improved. The operation principle of the new control strategy is introduced and the control effect is simulated. Then the output power and voltage characteristics of an ISOI system under this new control strategy are analyzed. The stability of the proposed control strategy is explored base on a Hurwitz criterion, and the design guide line of the control strategy is given. A two module ISOI system prototype is fabricated and tested in the laboratory. Experimental results verify the effectiveness of the proposed control strategy.

• Journal of Power Electronics
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• 제12권3호
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• pp.439-447
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• 2012

In this paper, an input-series auxiliary power supply scheme is proposed, which is suitable for high input voltage and multiple-output applications. The power supply scheme is based on a two-transistor forward topology, all of the series modules have a common duty ratio, all the switches are turned on and off simultaneously, and the whole circuit has a single power transformer. It does not require an additional controller but still achieves efficient input voltage sharing (IVS) for each series module through its inherent transformer-integration strategy. The IVS process of this power supply scheme is analyzed in detail and the design considerations for the related parameters are given. Finally, a 100W multiple-output auxiliary power supply prototype is built, and the experimental results verify the feasibility of the proposed scheme and the validity of the theoretical analysis.

• Journal of Power Electronics
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• 제10권6호
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• pp.673-679
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• 2010

Input-series-output-parallel (ISOP) connected DC-DC converters enable low voltage rating switches to be used in high voltage input applications. In this paper, a DSP is adopted to generate digital phase-shifted PWM signals and to fulfill the closed-loop control function for ISOP connected two full-bridge DC-DC converters. Moreover, a stable output current sharing control strategy is proposed for the system, with which equal sharing of the input voltage and the load current can be achieved without any input voltage control loops. Based on small signal analysis with the state space average method, a loop gain design with the proposed scheme is made. Compared with the conventional IVS scheme, the proposed strategy leads to simplification of the output voltage regulator design and better static and dynamic responses. The effectiveness of the proposed control strategy is verified by the simulation and experimental results of an ISOP system made up of two full-bridge DC-DC converters.