Lithium-ion batteries are widely used in new energy vehicles, especially electric vehicles. Temperature estimation is very important for battery life and safety. However, current temperature measurement methods cannot accurately measure the battery internal temperature. In this paper, a new method for battery temperature estimation based on an improved magnetic nanoparticle thermometer (MNPT) is proposed. The influence of dc magnetic field on temperature accuracy of a MNPT is firstly studied, the optimal dc magnetic field is found out under limitation of maximum temperature sensitivity and minimum temperature error, a new model of an improved MNPT is also established based on the ratio of first and second harmonics, and then the Lithium-ion battery temperature is estimated by use of the improved MNPT, the simulation and experiment results show that the improved MNPT can accurately estimate the battery internal temperature, which provides a new method for monitoring battery temperature of a new energy vehicle.

Aiming at the problem of a small parameter value range when a one-dimensional chaotic system presents a chaotic state, this paper proposes a new type of hybrid power exponential chaotic system (HPECS). HPECS combines the classic one-dimensional Sine chaotic system to form a new chaotic system (HPECS-SS). Experiments show that the obtained new chaotic system has better chaotic performance, a more extensive parameter value range, and higher sensitivity. Simultaneously, on the basis of HPECS-SS, a new image encryption algorithm is proposed. The algorithm uses the key generated by the SHA-512 algorithm and HPECS-SS to iteratively output the chaotic sequence, SFY algorithm combines the chaotic sequence to perform two rounds of scrambling on the plaintext sequence to obtain the scrambling sequence, and finally, through the modulus operation to diffuse the scrambling sequence to form the encryption matrix of the plaintext image, simulation experiment analysis shows that the algorithm has a large key space, good encryption effect, and security; the pixel change rate (NPCR) and the normalized average change intensity (UACI) are close to ideal values which can resist various cryptanalysis and attacks.

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By analysis of the low degree of intelligence of the traditional lighting control methods, the paper uses the singlechip microcomputer for the control core, and uses a pyroelectric infrared technology to detect the existence of the human body, light sensors to sense the light intensity; the interface uses infrared sensor module, photosensitive sensor module, relay module to transmit the signal, which based on ZigBee wireless network. The main function of the design is to realize that the lighting can intelligently adjust the brightness according to the indoor light intensity when people in door, and it can turn off the light when people left. The circuit and program design of this system is flexible, and the system achieves the effect of intelligent energy saving control.

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