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The P-U curve of the PV (photovoltaic) system has multi-peak characteristics under non-uniform irradiance conditions (NUIC). The conventional MPPT algorithm can only track the local maximum power points, therefore, PV system fails to work at the global optimum, causing serious energy loss. How to track its global maximum power point is of great significance for the PV system to maintain an efficient output state. PSO-AFSA (Particle Swarm Optimization Artificial Fish Swarm Algorithm) is a global maximum power point tracking (GMPPT) algorithm with strong global search capability, but the convergence speed and accuracy of the algorithm are limited. To solve the mentioned problems, a modified AESPSO-AFSA GMPPT algorithm is proposed in this paper by introducing the evolution strategy into PSO-AFSA algorithm. Simulation results show that under NUIC, compared with the conventional P&O and PSO-AFSA algorithm, the proposed algorithm has well performance on getting out of the local optimal solution and improving the global optimal solution of the individual neighborhood, the convergence speed and convergence accuracy are also increased.

In order to deal with the difficulty of finding misplaced books caused by disordered borrowing and enhance borrowing convenience, a Low-power Localization System for Wireless Sensor Network (WSNs) based on CC2530 was designed and applied in practice. With the RFID technology, the proposed system succeed in localizing library books and guiding readers to find the their required books with high efficiency, which greatly modifies the process of management for librarians.

RSSI-based localization technology is widely concerned for WSN node localization. However, this kind of methods has relatively larger localization error, and its localization rate is low. In order to enhance the localization accuracy, the localization error is declined by considering the construction of signal transmission model as well as the ranging process, and a modified weighted centroid localization algorithm is proposed in this paper. The simulation results show that the proposed approach can effectively reduce the three-dimensional node localization error.

Magnetic coupled resonant wireless energy transmission technology is a way of wireless energy transmission. In the field of magnetic coupled resonant wireless energy transmission system, the distance between the transmitting coil and the receiving coil is too large and the position is fixed. The system is in the state of under coupling, which causes the system output power to be too small. The case of adding the relay coil between the transmitting coil and the receiving coil is proposed to improve the output power. Considering that the introduction of the relay coil may make the system’s charging state transition from under coupling state to over coupling state directly, the frequency splitting phenomenon is suppressed by adjusting the position of the relay coil, the angle of the rotating relay coil, the output power before and after the measures is changed. The simulation experiment shows that the measures of increasing the relay coil and taking suppression of frequency division to restrain the frequency can greatly improve the output power.