With the rapid development of the electronic information industry, massive private data are continuously uploaded to the Internet, posing severe challenges to data security. Thus, a high-capacity private data information protection library based on correlation generator is proposed. For private data uploaded by multiple individuals or organizations, the proposed library enables efficient bulk protection. Through the biometric images held by individuals or organizations, correlation values are generated by the correlation generator, which are combined with such initial values of the four dimensional hyperchaotic system (4DHS) to generate private keys and master keys. The chaotic sequences generated by the iteration of the system are combined with the encryption scheme to provide effective protection of private data information. Afterwards, the scheme is tested for simulation and security, which verify the feasibility and security of the proposed scheme.

With the rapid development of the Internet, face recognition technology is widely used, which makes the protection of face database especially important. To protect the recognized faces, a multiface image compression encryption (MFICE) scheme is designed based on the electromagnetic radiation Ktz neuron (ERKN). Since only faces are to be encrypted, they are first extracted. Then the face images are compressed by using semi-tensor product compressed sensing (STP-CS) algorithm, and the compressed images are integrated into a large cube, i.e., a 3-D cube. After that, interface confusion algorithm, 3-D shuffling algorithm, and 3-D diffusion algorithm are sequently performed by using chaotic sequences generated by iteration of ERKN, and finally the ciphertext image cube is obtained. The proposed scheme is evaluated, and it performs well in terms of feasibility and security.

Synchronization between the primary and secondary sides is very important in wireless power transfer (WPT) systems. Especially in secondary-side control and bi-directional applications, the rectifier on the secondary side needs an accurate phase synchronization signal to properly control the conduction angle of the switches. However, the rectifier generates harmonic currents, making it impossible to obtain the synchronization signal directly by zero-crossing comparison of the secondary-side currents. The operating principle of the active rectifier in the WPT system is described. The harmonic currents generated by the active rectifier and the phenomenon of zero-crossing point forward shift caused by it are analyzed. The differences in the zero-crossing point forward shift between S-S and LCC-LCC systems are compared. In order to circumvent the effects of harmonics, a synchronization method based on a peak filter is proposed. The method is verified in simulation. The results show that after adding the filter to the control circuit, an accurate synchronization signal can be generated, and the circuit operates stably.

To improve the power supply reliability of the wireless power supply system of the transmission line online monitoring equipment and realize the information transmission at the transmitting side and the receiving side, this paper uses the coupling coil with taps to realize the coordinated transmission of power and information based on the wireless power transmission system with multiple relay coils. A power transmission model and information transmission equivalent circuit for the multi-relay coil wireless power transmission system are established in this paper to analyze the working characteristics of the power and information transmission paths and verifies the effectiveness of the proposed scheme through simulation. The simulation results show that the proposed scheme can achieve the cooperative transmission of information under the condition of satisfying the transmission power. The proposed scheme in this article can reduce the system size and is beneficial for adapting to the working environment of high-voltage insulator strings.

The coupler is essential in energy conversion in the wireless power transfer (WPT) system. Depending on the requirements of the appliances, the receiving coils have different structures, and their coupling magnetic fields are diverse, such as circular coils and solenoidal coils. Transmitters that generate flux in a single direction are difficult to compatible with different types of receiving coils, so this paper proposes a new transmitter with compatibility that can generate flux in two directions. Through finite-element analysis (FEA), the ferrite width, transmitter diameter, and coil position are discussed to find the best coupling design and compare and analyze the compatibility of the proposed circular and solenoidal structures. Simulation results show that the proposed structure has good coupling performance and is compatible with circular and solenoidal receiving coils. An experimental platform is built to verify the rationality of the proposed coupler structure.

Wireless charging technology greatly improves the flexibility and convenience of electric vehicles (EVs) charging. The alignment of coils directly affects the performance of the wireless charging system. The shift of the secondary coil leads to the decrease in transmission power and efficiency. Aiming to solve the abovementioned problems, in this article a mesh-based accurate positioning strategy for the EV wireless charging coils has been proposed. The strategy takes the center of the primary coil as the origin and divides the meshed reference points in the plane of the secondary coil. It is based on the voltage principle induced by the detection coils installed on the secondary coil. The coordinate calculation formula is derived by fitting the curve of the induction voltage with distance. The centimeter-level positioning of the secondary coil is realized in the X and Y directions of the horizontal plane. The proposed strategy is verified by simulations and experiments. The effectiveness and stability of the proposed method are verified by many simulations and experiments. Without considering the rotation of the coil, the maximum error is within 3 cm in a 5 cm mesh width. The positioning strategy helps to align the coils and improves the electrical transmission performance. It is also helpful for automatic parking, unmanned vehicle, and other industrial applications.

To deal with the problems of charging for inspection robots in substations such as frequent charging, complex mechanical interface, and insufficient battery capacity, a dynamic wireless charging system is proposed. The structure design of energy pickup device and the indispensable positioning strategy is presented in this paper. First, the dynamic wireless charging systems based on centralized energy pickup and decentralized energy pickup (DEP) are investigated and the unified circuit model is built for two kinds of systems simultaneously. Based on the comparison of working performances, the DEP structure is selected as the pickup device in this paper. Then, the positioning scheme is realized based on imitative relaying coil structure including the DEP device and the additional sensor coil. A switching control strategy of the segmented transmitting coils is proposed further to implement the dynamic wireless charging for inspection robots. The theoretical analyses are validated by the relevant experiments.