Dong-Choon Lee

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In this paper, a feedback linearization technique is proposed to control the output voltage control of three-phase uninterruptible power supply systems. First, a nonlinear model including the output LC filters is derived from the power balance condition between the inverter output terminal and the load side. Then, input–output feedback linearization is(More)
This paper proposes a new maximum power point tracking (MPPT) algorithm for variable-speed wind turbine systems, which takes advantage of the rotor inertia power. In this method, a proportional controller is added to the power control to effectively reduce the moment of inertia of the wind turbines, which can improve the fast performance of the MPPT(More)
In this paper, a fast voltage control scheme for PWM voltage source power converters applying a feedback linearization technique is proposed. First, a nonlinear system modeling is derived with state variables of the input current and the output voltage by using the power balance of the input and output. By input-output feedback linearization, the system is(More)
In this paper, an improved nonlinear control strategy of the inverter output voltage for the three-phase UPS systems is proposed. At first, a nonlinear modeling including the output LC filters is derived from the power balance condition between the inverter output and load sides. Then input-output feedback linearization is applied to the nonlinear model,(More)
This paper presents a new velocity estimation strategy of a nonsalient permanent-magnet synchronous motor (PMSM) drive without a high-frequency signal injection or special pulsewidth-modulation (PWM) pattern. This approach is based on the d-axis current regulator output voltage of the drive system that has the information of rotor position error. Rotor(More)
In this paper, a new online capacitance estimation method for dc-link capacitors in a three-phase ac/dc/ac pulsewidth-modulation converter is proposed. A controlled ac voltage with a lower frequency than the line frequency is injected into the dc-link voltage, which then causes ac power ripples at the dc output side. By extracting the ac power component on(More)