Dynamic power management with hybrid power sources

Abstract

DPM (Dynamic Power Management) is an effective technique for reducing the energy consumption of embedded systems that is based on migrating to a low power state when possible. While conventional DPM minimizes the energy consumption of the embedded system, it does not utilize the properties of the power source. Alternative power sources such as fuel cells (FCs) have substantially different power and efficiency characteristics that have to be taken into account while developing policies that maximize their operational lifetime. In this paper, we present a new DPM policy for embedded systems powered by FC based hybrid source. We develop an optimization framework that explicitly considers the FC system efficiency and is aimed at minimizing the fuel consumption. Next we apply this optimization framework on top of a prediction based DPM policy to develop a new fuel-efficient DPM scheme. The proposed algorithm was applied to a real trace based MPEG encoding example and demonstrated up to 32% more system lifetime extension compared to a competing scheme.

Energy management of DVS-DPM enabled embedded systems powered by fuel cell-battery hybrid source

“…When we cannot control the FC output, as in our previous work [15], the minimal load energy consumption does not correspond to the minimal fuel consumption. However, if the FC has the capability to change its output power by controlling the fuel flow rate, the load energy minimization is an essential step for fuel minimization [16,17]. This will be formally proved in Section 4.1.2.…”

“…Both [15,16] considered the FC system efficiency to be a constant, which is true for our first hybrid power source prototype built with PWM DC-DC converter and constant fan speed control policy. In [17], we proposed a more efficient FC configuration with a PWM-PFM DC-DC converter and variable fan speed control policy that had higher efficiency. We proposed an efficient FC output control policy and applied this policy on top of a traditional DPM algorithm traditional DPM algorithm to derive a FC-aware DVS-DPM policy.…”

A fuel-cell-battery hybrid for portable embedded systems

“…So, the best charge management policy for portable embedded systems does not only track it, but also actively reshapes it. We have presented procedures for reshaping the load profile based on a combination of FC control and embedded system power management using DVS [Zhuo et al 2006a[Zhuo et al , 2006b] and DPM [Zhuo et al 2007a[Zhuo et al , 2007b]. …”

“…This was presented in Zhuo et al [2007a] and has been included here for the sake of completeness. The goal is to maximize the lifetime of the FC-Bh system for a given amount of fuel, that is, minimization of the fuel consumption.…”

Modeling of DC-link Connected Multiple-converter System Operating as Microgrid

“…Especially the use in alternative and renewable sources utilization can be counted among the most interesting applications [4], [6], [7]. Due to the nature of this kind of systems, the supervisory control is required, especially for the performance of power and energy management [8], [9], [10], with the goal to maximize the efficiency of the overall system under the different operating conditions. However, the converters of that complexity become relatively hard to manage, and in the early stage of development, a lot of attention has to be given to the safety of the operation, which has to be set to a much higher level than the one required in the normal operation.…”