Title :
A DC-link voltage balancing algorithm for 3-level converter using the zero sequence current
Author :
Lim, Sun-kyoung ; Kim, Jun-Ha ; Nam, Kwanghee
Author_Institution :
Dept. of Electr. Eng., Postech Univ., Pohang, South Korea
Abstract :
The voltage unbalance between the upper and lower capacitors is an important problem in the three-level PWM converter system, and it is known that the voltage unbalance is directly related to the zero sequence. In this paper, we provide a zero sequence current path by connecting the neutral point of the source transformer to the midpoint of the DC link capacitors. Further, we control the unbalanced voltage with the zero sequence current. The zero sequence current is controlled by the zero sequence voltage made from sinusoidal PWM. The effectiveness of the proposed scheme is verified by computer simulations and experiment
Keywords :
PWM power convertors; electric current control; voltage control; 3-level converter; DC link capacitors midpoint; DC-link voltage balancing algorithm; lower capacitors; neutral point; sinusoidal PWM; source transformer; unbalanced voltage control; upper capacitors; zero sequence current; zero sequence voltage; Capacitors; Computer simulation; Conductors; Joining processes; Phase transformers; Pulse width modulation; Pulse width modulation converters; Pulse width modulation inverters; Topology; Voltage control;
Conference_Titel :
Power Electronics Specialists Conference, 1999. PESC 99. 30th Annual IEEE
Conference_Location :
Charleston, SC
Print_ISBN :
0-7803-5421-4
DOI :
10.1109/PESC.1999.785646
