مقاله انگلیسی رایگان در مورد محصول انرژی خورشیدی در کلاه دوچرخه – IEEE 2017

The monitoring of human activity is, on the technical point of view, a continuous challenge in terms of design and development of innovative smart and wearable systems that aims to the dimension reduction and to the increase of the energy autonomy. These devices can implement many features, such as the human physical activities [1-2] or sport performance assessment [3], this last relying on accurate measurements carried out with optimized instrumentation [4]. In order to ensure the good performance of a smart device, especially in terms of proper accuracy [5-8], specific algorithms are required. The optimization of the computational costs for those algorithms [9-12] is an absolute requirement to guarantee a long duration of power supply. Yet this might still not sufficient to provide the necessary autonomy, especially if large size batteries cannot be used. For outdoor sport activities such as running, cycling and hiking, when smart sensors are involved, an optimal management of the tradeoff between energy supply weight and duration must be considered. Almost all smart sensors are based on Microcontroller Units (MCU) that require a steady supply of current at a voltage that can be regulated at 3.3V for standard digital electronics. Voltage regulation is, in general, achieved through step-up converters. The magnetic elements that are often present in such converters are still an open modeling problem [13-16], especially at small scales. Regardless of the technological advances achieved, battery life is still probably the most central issue. This topic is even more central for outdoor prolonged activities or in urban areas, where distributed power generation using renewable energy [17] is a leading technology for smart sensor integration. Among different approaches that can be used to power the sensors, energy harvesting by photovoltaic (PV) effect is one of the most interesting. Indeed, since the obtained power depends strongly on the irradiation level, even for outdoor activities an accumulator is in general a required component for the power supply unit (PSU). Another key aspect is the management of the strong non-linear currentvoltage (I-V) characteristic of the device. The voltage generated by the PV device needs to be adapted for the application by a direct current converter (DC-DC). At the same time, the DC-DC must manage its input resistance to keep the PV device operating point as close as possible to the maximum power point. This process is called Maximum Power Point Tracking (MPPT). This is a major issue for PV energy generation at any scale, and becomes more dramatic for rapidly changing environmental (irradiance G and temperature T) conditions.