Power management control for off-grid solar hydrogen production and utilisation system

Development of a mobile photovoltaic stand-alone energy supply system

“…For illustration purpose a block diagram of a typical mobile stand-alone PV system is shown in Figure 1. A. PV system Several researchers have addressed the development of an accurate PV model, and the design and application of such systems [1] - [7], [11], [12] and [13]. In this paper, a common but accurate PV model presented in [11] is adopted.…”

“…Therefore, a buck DC/DC converter is chosen to drive a low voltage battery pack from a higher voltage solar panel and a maximum power point tracking (MPPT) controller is needed to be developed in order to adjust the duty cycle of the converter [13]. This allows for optimal performance of the system by generating maximum solar power.…”

“…However, the energy conversion efficiency of a PV module is very low and to overcome this problem and to get the maximum possible efficiency, the design of all the elements of the PV system has to be considered and optimized. The PV system possess strong non-linear characteristics and there is a single operating point which is called the maximum power point (MPP) that provides the maximum power under certain light density and cell temperature conditions [11], [13] and [21]. There is a probable mismatch between the load current and voltage characteristics and the MPP.…”

“…Therefore, tracking the MPP is essential to improve the system efficiency and performance optimization. Recent research efforts show that several different control methods for the maximum power point tracking (MPPT) of a PV system under variable temperature and isolation conditions has been investigated, see for example [11], [13], [22], [23] and [24]. There are many ways of distinguishing and grouping the control methods that seek the MPP from a PV system.…”

Hybrid hydrogen-battery systems for renewable off-grid telecom power

“…Previous studies of hybrid hydrogen-battery storage systems have shown that heavy battery use can lead to more efficient systems with reduced PV/wind requirements, but with deep discharges and/or long periods at low SOC which adversely affect battery life [17,19,25]. Others have shown that batteries can be protected through reduced usage by placing a heavy reliance on hydrogen, but with adverse impacts on system efficiency and renewable power capacity [20,26,27]. Here we show that a compromise can be reached, with batteries improving system efficiency and reducing PV/wind capacity requirements through regular daily cycling, while the hydrogen component serves to maintain battery SOC within narrow limits and so extend battery life.…”