No abstract

No abstract

No abstract

This study proposes a new power decoupling circuit applied to the single-phase current source converter (SCSC). Differing from the existing power decoupling technologies, the proposed power decoupling circuit could be viewed as a controlled voltage source in series with the DC inductor, and work with SCSC independently. That facilitates the separate design of the modulation schemes and the control algorithms for the power decoupling circuit and SCSC, and reduces the operation restrictions imposed by requirements. The fundamental principle of the proposed converter is analysed, and the voltage reference requirement for the buffer capacitor is investigated. To guarantee high input current quality of SCSC, a control method, where the input current is treated as a virtual control input, is proposed. Finally the effectiveness of this topology is verified by the simulations and experimental results.

No abstract

1-This paper proposes a single-phase PFC rectifier to achieve high power factor, wide output voltage range, and ripple power decoupling without using electrolytic capacitors. It consists of two parts: power factor correction (PFC) circuit and output voltage regulation circuit. The load side is involved in both parts, which is different from the regular two-stage conversion structure. The proposed rectifier can be directly applied to low voltage cases due to the wide output voltage range. And the decoupling capacitor voltage can be smaller than the peak grid voltage, which reduces the voltage stress. Besides, the low frequency ripple power buffer is implemented without a dedicated power-buffering controller. This paper firstly introduces the circuit structure, operation principles, and control method. Then, the system design consideration is given. Finally, the effectiveness of the proposed topology is verified by the simulations and experimental results. Index Terms-Active power decoupling, closed-loop control, low frequency ripple power, PFC, wide output voltage.

An efficient strategy for the synthesis of a wide variety of coordination complexes has been developed. The synthetic protocol involves a solvothermal in situ metal-ligand reaction of picolinaldehyde, ammonium acetate, and transition-metal ions, leading to the generation of 12 coordination complexes supported by a novel class of substituted 1-pyridineimidazo[1,5-a]pyridine ligands (L1-L5). The ligands L1-L5 were afforded by metal-mediated controllable conversion of the aldehyde group of picolialdehyde into a ketone and secondary, tertiary, and quaternary carbon centers, respectively. Complexes of various nuclearities were obtained: from mono-, di-, and tetranuclear to 1D chain polymers. The structures of the in situ formed complexes could be controlled rationally via the choice of appropriate starting materials and tuning of the ratio of the starting materials. The plausible mechanisms for the formation of the ligands L1-L5 were proposed.

A transformer-less dynamic voltage restorer (DVR) with bipolar voltage gain capability is proposed in this study. The DVR is formed by a three-leg ac/ac converter with its output capacitor in series with the transmission line. Since the energy used for voltage compensation is obtained from the grid, long-time voltage disturbances can be compensated without using bulky energy storage elements. As a result, the proposed DVR has the features of compact structure, light weight, and low cost. Moreover, it also has a high reliability as the commutation problem is avoided by adopting the proposed modulation strategy. A detailed analysis of the topology structure and operation principle is given, followed by the developed control method. Finally, simulations and experimental results are presented to verify the validity of the DVR.