TY - GEN
T1 - Thermal effects on the stability of piezoelectric transformers based ballasts for cold cathode fluorescent lamps
AU - Peretz, Mor Mordechai
AU - Ben-Yaakov, Sam
PY - 2006/12/1
Y1 - 2006/12/1
N2 - The Envelope Impedance (EI) concept was used to investigate the thermal effects on the stability of Piezoelectric Transformers (PT) based ballasts for Cold Cathode Fluorescent Lamps (CCFL) systems. The envelope analysis of the CCFL, which was verified experimentally, revealed that the magnitude of the negative EI decreases with temperature. This might cause the system to become unstable at low temperatures due to the fact that the loop gain of the PT-CCFL system might encircle the (-1, 0) point in the Nyquist plan. In such cases, the PT-CCFL system may enter a quasistable oscillatory operation mode in which the current is AM modulated by a low frequency parasitic signal. This phenomenon is analyzed and explained by considering the temperature effect on the EI of the CCFL. The results of this work provide an insight into the stability issue of the PT-CCFL system, and could help in finding remedies to the instability.
AB - The Envelope Impedance (EI) concept was used to investigate the thermal effects on the stability of Piezoelectric Transformers (PT) based ballasts for Cold Cathode Fluorescent Lamps (CCFL) systems. The envelope analysis of the CCFL, which was verified experimentally, revealed that the magnitude of the negative EI decreases with temperature. This might cause the system to become unstable at low temperatures due to the fact that the loop gain of the PT-CCFL system might encircle the (-1, 0) point in the Nyquist plan. In such cases, the PT-CCFL system may enter a quasistable oscillatory operation mode in which the current is AM modulated by a low frequency parasitic signal. This phenomenon is analyzed and explained by considering the temperature effect on the EI of the CCFL. The results of this work provide an insight into the stability issue of the PT-CCFL system, and could help in finding remedies to the instability.
UR - http://www.scopus.com/inward/record.url?scp=42449090202&partnerID=8YFLogxK
U2 - 10.1109/PESC.2006.1712120
DO - 10.1109/PESC.2006.1712120
M3 - Conference contribution
AN - SCOPUS:42449090202
SN - 0780397169
SN - 9780780397163
T3 - PESC Record - IEEE Annual Power Electronics Specialists Conference
BT - 37th IEEE Power Electronics Specialists Conference 2006, PESC'06
T2 - 37th IEEE Power Electronics Specialists Conference 2006, PESC'06
Y2 - 18 June 2006 through 22 June 2006
ER -