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As the core component of wearable electronic devices, flexible energy storage materials play an irreplaceable role. At present, it is still a challenge to prepare flexible electrode materials with high energy density. In this paper, a polyaniline‐based composite flexible conductive hydrogel (PPG‐P) with a two‐level conductive network is successfully prepared by a secondary induced assembly in situ polymerization method. The special conductive structure greatly promotes the efficiency of charge transfer and the utilization of electroactive substances, so that PPG‐P exhibits excellent electrochemical performance. In a three‐electrode system, PPG‐P has a mass‐specific capacitance as high as 989 F g−1 (0.5 A g−1). After 1000 charge and discharge cycles, the capacitance retention is 87%. Symmetrical flexible supercapacitors based on PPG‐P have high specific capacitance (176 F g−1/0.5 A g−1) and high energy density (15.6 Wh kg−1). After 1000 cycles of constant current charge and discharge, the capacitance maintains 78.1%. The preparation of PPG‐P with a hierarchical structure demonstrates the possibility of achieving high energy density in flexible electrode materials, which has great application potential in the development of energy storage elements in wearable devices. [ABSTRACT FROM AUTHOR]

Inverter‐side current feedback control (ICFC) has been extensively adopted in distributed generation systems because of its simple implementation and better consistency with actual operating conditions. At the same time, when there are a large number of background harmonics in the grid, capacitor voltage feedforward (CVF) is usually added to the system for its suppression. This method could make the system keep the first‐order characteristics under the analogue control. However, under digital control, due to the digital control delay, a reverse resonance peak will be generated in the loop gain, which makes the system unstable in the weak grid. In order to solve the aforementioned problems, this study proposes a feedforward phase compensation method of LCL grid‐connected inverter based on the all‐pass filter (AF). By introducing AF into the CVF channel, the phase lag in the range of reverse resonance peak frequency is compensated, so as to enhance the robustness of the system in the weak grid. At the same time, this study gives the detailed design process of the proposed method. Experimental results on a 3‐kW prototype are provided, and the effectiveness of the proposed control method is verified.. [ABSTRACT FROM AUTHOR]

In this study, a novel control scheme for the discontinuous conduction mode (DCM) operation boost power factor correction (PFC) converter is proposed. Instead of adopting constant duty cycle (CDC) control, variable duty cycle control or frequency control, the magnetic control or variable inductor control is adopted to regulate the output voltage, so CDC and switching frequency can be implemented for the switch. The operation principles of the proposed control scheme are discussed in details, and the analysis of the input current, power factor, boundary condition and design considerations are presented. In addition, the modelling of the variable inductor and the DCM operation boost PFC converter with variable inductor are derived in detail, by linearising the non-linear components, the model of the DCM operation boost PFC converter with the proposed control scheme can be obtained, and the design procedures of the PI controller are presented. Finally, a 70 W experimental prototype is built to verify the theoretical analysis and the effectiveness of the proposed control scheme. [ABSTRACT FROM AUTHOR]