Lijun Hang

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—In the last years, the use of distributed uninterrupt-ible power supply (UPS) systems has been growing into the market , becoming an alternative to large conventional UPS systems. In addition, with the increasing interest in renewable energy integration and distributed generation, distributed UPS systems can be a suitable solution for storage energy in(More)
This paper presents a modular cascaded H-bridge multilevel photovoltaic (PV) inverter for single- or three-phase grid-connected applications. The modular cascaded multilevel topology helps to improve the efficiency and flexibility of PV systems. To realize better utilization of PV modules and maximize the solar energy extraction, a distributed maximum power(More)
—Unbalanced grids introduce performance deterioration for the Vienna rectifier topology by producing twice fundamental frequency ripple in the dc-link voltage and input active/reactive power. A traditional control strategy is the input current tracking scheme, which can work under any unbalanced conditions, but it cannot eliminate the input power ripple and(More)
— A three-phase cascaded voltage source inverter (VSI) for a grid-connected photovoltaic (PV) system is proposed in this paper. The topology consists of three traditional two-level six-switch VSIs interconnected through inductors. Each VSI unit is fed by a string of PV panels. To realize the central control of the proposed system, the equivalent model and(More)
— The LCCL control strategy, which was brought forward as a solution for the resonance of LCL-filter, provides good steady-state performance but unsatisfactory dynamic performance. In this paper, based on an improved discrete state space model and state observer of the LCCL control, a new optimized pole placement strategy is proposed to achieve the best(More)
—In this project to develop a reconfigurable electrical grid emulator, a Hardware Test-Bed (HTB) is being developed that emulates large scale power system generators and loads by using power electronic converters. Source converters in the HTB system are designed to emulate generators. A synchronous generator model is implemented in the converter to(More)