Heung-Geun Kim

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This paper proposes a low-voltage ride-through scheme for the permanent magnet synchronous generator (PMSG) wind power system at the grid voltage sag. The dc-link voltage is controlled by the generator-side converter instead of the grid-side converter (GSC). Considering the nonlinear relationship between the generator speed &#x03C9;<sub>m</sub> and the(More)
This paper proposes a phase-locked loop (PLL)-based seamless transfer control method between grid-connected and islanding modes in a three-phase grid-connected inverter. The PLL is used to synchronize the phase of the load voltage to a grid voltage in grid-connected operation, and to generate an angle with the desired frequency in islanding operation. The(More)
This paper proposes a new dead time compensation method for a PWM inverter. Recently, PWM inverters are widely used for industrial applications, such as ac motor drives, distributed grid-connected systems and a static synchronous compensator (STATCOM). The nonlinear characteristics of the switch and the dead time cause a current distortion and a(More)
This paper presents the MPPT (Maximum Power Point Tracking) and PCC (Point of Common Coupling) current control strategy for photovoltaic (PV) grid-connected generating system using the quasi-Z-source inverter (QZSI). At first, in order to explain the above controllers, the characteristic of QZSI is analyzed. And then, the MPPT control technique with a(More)
This paper deals with a design method of LCL filter for grid-connected three-phase PWM voltage source inverters (VSI). By analyzing the total harmonic distortion of the current (THD<inf>i</inf>) in the inverter-side inductor and the ripple attenuation factor of the current (RAF) injected to the grid through the LCL network, the parameter of LCL can be(More)
Distributed generators (DG), such as photovoltaic cells, are low cost, highly reliable and have electronic interfaces and reduced emissions. Even with the mentioned benefits, there are technical limits on the degree to which DG can be connected. One of these technical concerns is the islanding phenomenon. In utility practice at the present time, accidental(More)
This paper proposes a new topology named the active-switched-capacitor/switched-inductor quasi-Z -source inverter (ASC/SL-qZSI), which is based on a traditional qZSI topology. Compared to other qZSI-based topologies under the same operating conditions, the proposed ASC/SL-qZSI provides higher boost ability, requires fewer passive components such as(More)
This paper proposes a robust control strategy of the PMSG wind power system for the grid voltage sag. The DC-link voltage control is achieved by the generatorside converter instead of the grid-side converter. Considering the nonlinear relationship between the generator speed (&#x03C9;<inf>m</inf>) and DC-link voltage (v<inf>dc</inf>), a DC-link voltage(More)
This paper presents a novel single-phase PWM ac-ac converters that can solve commutation problem in single-phase direct ac-ac converter without sensing input voltage polarity. By using the basic switching cell structure and the coupled inductors, the proposed ac-ac converter can be short and open-circuited without damaging switching devices. A 200 W(More)