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For boost power factor correction (PFC) converters operating in critical conduction mode (CRM), charge compensation strategies are utilized to improve input current distortion. However, since massive calculations are required under complex working conditions, it is difficult to achieve accurate charge compensation with limited real-time computing resources. To solve this issue, this paper proposes an adaptive charge-compensation-based variable on-time (ACVOT) control strategy. The ACVOT controller calculates the required switching on-time by adding a fundamental value and an extended on-time. The fundamental value is adjusted by the loop compensator in each half-line cycle to provide a basic bias. The extended on-time is calculated based on partial charge compensation equation in each switching cycle to reduce the distortion. Compared with conventional digital variable on-time (VOT) control, the proposed strategy improves the input current total harmonics distortion (THD) and reduces the LUT/register resources by 54%/43% in FPGA realization. To verify the effectiveness of the proposed strategy, a 200 W prototype is built using the GaN HEMT transistor, where the THD is reduced to 1.4% at full load. [ABSTRACT FROM AUTHOR]

The solar array drive assembly (SADA) slip ring is a critical link that provides electrical power and electric signal transmission between solar arrays and satellite power systems, which is prone to arc faults in the space environment. If these arc faults cannot be detected and eliminated quickly enough, they will seriously threaten the safety of the satellite power system and the satellite. In this paper, a fast arc detection method based on fractal dimension is proposed that adapts to different operating modes of power systems. The detection method collects the current differential signal data flowing through the SADA slip ring, and, according to the trend of the fractal dimension change in this signal, the fault identification algorithm is designed for different operating modes of the power system to achieve real-time and rapid identification of arc faults. Finally, the effectiveness of the proposed method is demonstrated using test data under several different fault conditions. [ABSTRACT FROM AUTHOR]

This paper presents an Optimized Sensorless Charge Balance (OSCB) controller based on a damped current model for flyback converter operating in Discontinuous Conduction Mode (DCM). By solving total differential equations of non-ideal transformer currents, the damped current model is derived with consideration of parasitics, leakage inductance of transformer, and the Resistor-Capacitor-Diode (RCD) snubber circuit. Based on the proposed model, current observation and control algorithms of the Sensorless Charge Balance (SCB) controller are optimized, which forms the OSCB control strategy. The average current damping is considered in the equivalent discrete-time small signal model. Furthermore, frequency analyses show that OSCB controller achieves higher closed-loop bandwidth and lower overshoot than a SCB controller, which indicates an improved transient performance. Finally, both OSCB and conventional SCB controllers are experimentally evaluated on a flyback converter prototype. [ABSTRACT FROM AUTHOR]