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Chenguang Shi,Fei Wang,Mathini Sellathurai,Jianjiang Zhou,Huan Zhang 한국전자통신연구원 2016 ETRI Journal Vol.38 No.1
This paper addresses the problem of robust waveform design for distributed multiple-radar systems (DMRSs) based on low probability of intercept (LPI), where signal-to-interference-plus-noise ratio (SINR) and mutual information (MI) are utilized as the metrics for target detection and information extraction, respectively. Recognizing that a precise characterization of a target spectrum is impossible to capture in practice, we consider that a target spectrum lies in an uncertainty class bounded by known upper and lower bounds. Based on this model, robust waveform design approaches for the DMRS are developed based on LPI-SINR and LPI-MI criteria, where the total transmitting energy is minimized for a given system performance. Numerical results show the effectiveness of the proposed approaches.
Gao, Ming,Yu, Weichen,Wang, Shanshan,Shi, Jianjiang The Korean Institute of Power Electronics 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.10
Due to their advantages of reduced cost, integrated multi-port converters (MPCs) with fewer components have received extensive attention. In this article, by extracting the concept of series/parallel input pulsating cells (IPCs) and output pulsating cells (OPCs), a set of syntheses for generating MPCs composed of IPCs and OPCs is proposed. When compared with the existing synthesis method for non-isolated MPCs, the proposed approach employs only one inductor and features single-stage power conversion between any two ports, which offers benefits in terms of compact size and high efficiency. Two design examples are shown to demonstrate the worth of proposed methodology. The operation principles are first analyzed. The pulsewidth modulation (PWM) and power control schemes are explained and designed in detail. To design the controllers, small-signal models for each of the operation modes are also extracted. Meanwhile, the characteristics of pulsating cells with different configurations are discussed and compared. The theoretical analysis is validated by simulation and experimental results for different operation conditions.
Line-Interactive UPS for Low-Voltage Microgrids
Ping Zhang,Huanyu Cai,Hengyang Zhao,Jianjiang Shi,Xiangning He 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.6
Line-interactive uninterruptible power supply (UPS) systems are good candidates for providing energy storage within a microgrid. In this paper, a control scheme for a line-interactive UPS system applied in a low-voltage microgrid is presented. It is based on the Q-w and P-E droop control to achieve a seamless transition between grid-connected and stand-alone operation modes. Moreover, a new model for designing the controllers is built in the dq-frame based on the instantaneous power definition. The new-built model takes into account the dynamic performance of the output impedance of the inverter in the dq-frame and can be evaluated in the time domain. Compared to the traditional model based on the instantaneous power definition, the new-built model is more accurate to describe the dynamic performance of the system. Simulation and experimental results obtained with a microgrid consisting of two 40-kW line-interactive UPS systems are given to validate the control strategy of the line-active UPS system and the accuracy of the new-built model.
Coupled inductor based zero‑voltage‑switching buck/boost converter
Shanshan Wang,Yihua Hu,Ming Gao,Jianjiang Shi,Tao Liu 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.7
This paper proposes a zero-voltage-switching (ZVS) Buck/Boost converter (BBC). In addition, an auxiliary circuit based on a coupled inductor is introduced to realize ZVS for the main MOSFETs. The magnetic coupling inductor plays the role of filtering and provides ZVS conditions for the main MOSFETs. Since all of the switches can achieve soft switching conditions, and the conduction loss of the auxiliary circuit is small, the conversion efficiency for the overall system is improved. When compared with the traditional ZVS implementation methods based on magnetic coupling inductors used in Buck, Boost, and Buck/Boost converters, the proposed topology can prevent current notches on the current waveform of the input source. Since there are no notches on the input source current, when the proposed ZVS implementation method is applied to an interleaved parallel BBC structure, it has a smaller current ripple of the input source. Finally, experimental results are given and analyzed. Based on these results, both the ZVS conditions and efficiency improvement are verified.
Line-Interactive UPS for Low-Voltage Microgrids
Zhang, Ping,Cai, Huanyu,Zhao, Hengyang,Shi, Jianjiang,He, Xiangning The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.6
Line-interactive uninterruptible power supply (UPS) systems are good candidates for providing energy storage within a microgrid. In this paper, a control scheme for a line-interactive UPS system applied in a low-voltage microgrid is presented. It is based on the Q-w and P-E droop control to achieve a seamless transition between grid-connected and stand-alone operation modes. Moreover, a new model for designing the controllers is built in the dq-frame based on the instantaneous power definition. The new-built model takes into account the dynamic performance of the output impedance of the inverter in the dq-frame and can be evaluated in the time domain. Compared to the traditional model based on the instantaneous power definition, the new-built model is more accurate to describe the dynamic performance of the system. Simulation and experimental results obtained with a microgrid consisting of two 40-kW line-interactive UPS systems are given to validate the control strategy of the line-active UPS system and the accuracy of the new-built model.
Ming Gao,Shanshan Wang,Weichen Yu,Tao Liu,Jianjiang Shi 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.12
A conventional boost three-port converter is combined with a coupled-inductor-based boost-flyback converter in this work to produce a high-step-up three-port converter. The proposed converter inherits the benefits of two conventional converters, including high voltage gain, few elements, and energy recycling of the leakage inductor. In addition, the voltage stresses of switches are considerably lower than the output voltage. Therefore, switches with low ON resistance can be selected to reduce the conduction loss. Additionally, the freewheel diodes are capable of zero-current switching. The operation principle can be divided into three modes of operation, and the three steady-state operation modes are analyzed under each of the three conduction modes. The operation principles of various modes, the voltage characteristics, the boundary of the coupled inductor, and the proposed converter’s control method are discussed in depth to provide detailed theoretical guidance to designers. Then, the simulation and experiment results of a laboratory prototype with an 18 V PV source, 24 V battery pack, and 180 V output are presented to validate the feasibility of the theoretical analysis.