Efficiency-Based Current Distribution Scheme for Scalable Digital Power Converters

Abstract

Abstract-The trend in next-generation switched-mode power supplies will lead to modular, scalable solutions which deliver power efficiently over a wide range of operation. This paper details a new approach to introduce more advanced control features to improve system efficiency into these scalable solutions. While these methods have been incorporated into multi-phase converters in the past, they all require the distribution of information among the individual converters. An advantage of the proposed method is that it does not require such communication signals between the individual power supplies and is therefore fully scalable and cost effective. A system comprising of individual, smart converters is proposed where each converter regulates its respective output power to a level with high efficiency. Converters not required for the delivered output power are shut down. The proposed approach is analysed theoretically. Implementation details for an FPGA experimental prototype system are given. The system performance for a four converter prototype system is analysed and discussed. The efficiency obtained is compared with the efficiency of a multi-phase system with phase-shedding operation and the efficiency of a system with independent power converters without phase shedding support.

Scalable Digital Power Controller With Phase Alignment and Frequency Synchronization

“…Firstly, the input voltage of the fourth converter (controlled by S3) is not coupled sufficiently with the top two converters due to unequal current distribution, which is in turn due to the current distribution scheme used [1] (and indirectly due to PCB layout). This reason is further Figure 12.…”

“…Also hot-plugging is not supported by this particular system. In [1], [13], [14], phase alignment has not been implemented to date.…”

“…Also hot-plugging is not supported by this particular system. In [1], Figure 5. Proposed digital core.…”

“…1), or the use of multi-phase converters (interleaved phases), provides several benefits such as an increase in effective switching frequency, reduced ripple voltage, improved transient performance and improved efficiency [1]- [5]. Conversely, issues not present in stand-alone converters arise [6]- [8].…”

Mathematical efficiency modeling of static power converters

“…In [4] the efficiency curve is employed to identify better regions of operation for systems of parallel converters such that the overall efficiency of the system is improved. Also, in [5] mathematical models for efficiency of power converters are employed in an algorithm to obtain the optimal power sharing so that systems of parallel converters are able to operate with maximum efficiency throughout its entire load range.…”