Aluminum electrolytic capacitor (AEC) is one of the most age-affected components in power electronic converters and its reliability has been a major concern. As the growth of service life, the equivalent series resistance (ESR) of AEC increases due to the loss of electrolyte. Therefore, online ESR estimation is critical for condition monitoring of AEC. This paper proposes an online ESR estimation method for output capacitor of boost converter. By analyzing the voltage ripple, ESR calculation model is derived. Based on the model, only output voltage and inductor current need to be measured, which can be obtained directly from double closed-loops converter. To implement this proposed method, a detailed extraction scheme based on wavelet transform denoising (WTD) is presented. Non-ideal factors (noise and voltage spikes) are analyzed and the superiority of the proposed parameter identification scheme is verified. The proposed estimation method can obtain ESR for the converter operating at different working conditions such as resistive loads and converter loads. Effect of temperature on ESR is incorporated for accurate determination of the health of capacitor. Simulation and experimental results are provided to verify the effectiveness of the method.

Hybrid cascaded multilevel inverters have been recognised as an important alternative in the medium‐voltage inverter market due to their high‐quality output and outstanding availability. To optimise the performance of voltage‐source converters, modulation technologies have attracted more and more attention. With conventional modulation technologies, the switches within a cell are not utilised at a uniform switching frequency, which is not benefit for reliability and modularity. To solve this problem, a modified hybrid modulation strategy based on unipolar frequency doubling is proposed for H‐bridge hybrid cascaded inverters. The equivalence of different multilevel carrier‐based modulation strategies is revealed and corresponding implement methods are provided. Based on the equivalent hybrid modulation strategy, a modified hybrid modulation strategy is presented by using unipolar frequency doubling. Compared with the conventional modulation strategies, the proposed strategy makes a more uniform use of the switches within a cell. The proposed strategy keeps the output quality and efficiency while the maximum switching frequency is decreased by half. The strategy has been successfully substantiated by the simulation and experimental results of a seven‐level hybrid cascaded inverter.

Condition monitoring has been recognised as an effective and low‐cost method to enhance the reliability and improve the maintainability of power electronic converters. Hybrid model‐based monitoring method is an advanced implementation means due to its non‐invasive ways. However, the existing hybrid model is not fit for boost‐derived converters for its ignorance of the suddenly change in the diode current caused by switching actions. To solve this problem, a correction term is introduced to modify the primary model. The inductor parasitic resistance is considered for higher accuracy and the gate signal sensor is cancelled for lower complexity. In order to verify the modified model, a parameter identification method based on wavelet denoising (WTD) and recursive least squares arithmetic is proposed. Non‐ideal factors (noise and voltage spikes) are analysed and the superiority of the proposed parameter identification scheme is verified. Compared to the primary model, the modified model can achieve higher identification accuracy with fewer sensors, which is more suitable for condition monitoring of Boost converters. The proposed model has been successfully substantiated by the simulation and experimental results of a Boost converter.

This paper presents an enhanced YOLOv8 model designed to address multi-target detection challenges in complex traffic scenarios. The model integrates the Squeeze-and-Excitation attention mechanism, the deformable convolution C2f module, and the smooth IoU loss function, achieving significant improvements in detection accuracy and robustness in various complex environments. Experimental results show that the enhanced YOLOv8 model outperforms existing YOLO solutions across multiple metrics, particularly in precision and recall. Specifically, the enhanced model achieves 83.8% precision and 82.7% recall, improving 1.05 times in precision and 1.1 times in recall compared to the average precision (79.7%) and recall (75.4%) of other YOLO series models. In terms of mAP_0.5, the enhanced model achieves 89%, representing a 1.05-fold improvement over the average mAP_0.5 (84.4%) of YOLO series models. For mAP_0.5:0.95, the enhanced model reaches 76.5%, which is a 1.1-fold improvement over the average mAP_0.5:0.95 (69.7%) of YOLO series models. These improvements demonstrate the superior performance of the proposed model in multi-scale and complex scenarios, providing strong support for intelligent transportation systems and autonomous driving.

This article proposes a high-gain transformerless three-port converter (TPC) for standalone photovoltaic (PV) systems. The TPC is designed and developed based on a dual-inductor high-gain two-port converter by utilizing one of the buffer capacitors to derive the third part for PV input. A hybrid pulse-frequency modulation scheme unified with a pulsewidth modulation control strategy is adopted, which realizes the maximum power point tracking control, load voltage regulation, and bidirectional energy flow at the battery port. The proposed TPC offers the unique advantages of high voltage gain, continuous battery port current, reduced power semiconductors, lower voltage stresses, common ground shared by all the ports, low-cost gate driver, and small size of the rear-end inductor. The working principle, steady-state characteristics, small-signal models, and the control method, including design conditions, are comprehensively analyzed. The correctness of the theoretical analysis is verified by developing a 300-W experimental prototype, which shows that the maximum efficiency is 97.7%.

Hybrid cascaded multilevel inverters have been proved to be an important alternative in the medium-voltage applications for their high-quality output. To reduce the use of dc sources, the single dc source cascaded H-bridge (SDS-CHB) inverter with the low-voltage dc source replaced by a capacitor is employed and investigated in this article. To address the challenge of the input capacitor voltage regulation, the charge/discharge modes with carrier-based pulsewidth modulation at different operation conditions are analyzed in detail and generally for all the combinations of load current magnitude and power factor from −1 to 1. The stability conditions for capacitor voltage control are analytically derived. Based on the analysis, a simple but effective capacitor voltage regulation strategy and an operation parameter optimization method are proposed. Within the identified stable operation regions, the proposed control strategy can keep the input capacitor voltage at the desired voltage level, i.e., half of the high-voltage cell dc source meanwhile can ensure the inverter high-quality output. The proposed operation parameter optimization method can minimize the output filter capacitor with good output. The capacitor voltage regulation strategy and operation parameter optimization method have been successfully substantiated by the simulation and experimental results of a seven-level hybrid cascaded inverter.