On the Potential of IGCTs in HVDC

Abstract

In today's VSC HVDC solutions, IGBTs (Insulated Gate Bipolar Transistors) are used exclusively, generally in module form where the Modular Multilevel C o n v e r t e r ( M M C ) i s c o n c e r n e d ; t h i s e n t a i l s a n u m b e r o f protective measures which increases complexity and cost. As w e m o v e t o h i g h e r t r a n s m i t t e d p o w e r s , t h e u s e o f I G C T s (Integrated Gate-Commutated Thyristors) would allow both higher voltages and currents while simultaneously reducing l o s s e s , f a i l u r e r a t e s a n d c o s t s , a s t h i s p a p e r w i l l t r y t o demonstrate by comparing current production IGCTS with both current module and press-pack IGBTs. Index Terms-HVDC transmission, Power semiconductor devices, Thermal analysis, AC-DC power converters, MMC2168-6777 (c)

MMC converter cells employing ultrahigh-voltage SiC bipolar power semiconductors

“…The use of IGCTs for HVDC converter cells has been experimentally verified in [11]. A comparison between conventional IGBT cells and IGCT cells regarding losses, reliability and cost of the converter has been presented in [12]. Wire-bonded modules (WBM), which are commonly used for IGBTs, fail into an open circuit if exposed to sufficiently high currents.…”

Current Source Modular Multilevel Converter: Detailed Analysis and STATCOM Application

“…To solve for the amplitude and phase of this 2 nd harmonic circulating current, the early assumptions of the arm currents in (16)- (17) are revised and the 2 nd harmonic circulating component is supposed to exist in the arm currents. That is,…”

“…In (44), either the upper or lower arm current is selected to be the output of the controller because the upper and lower arm currents are phase shifted by π radians. Solving (16), (17) and (44), the converter line current in terms of the upper arm current is expressed as…”

“…A reverse voltage blocking device can be an IGBT in series with a diode at the expense of losses and cost [13]. RB-IGBTs and IGCTs are the other alternatives which permits reverse blocking operation [15]- [17]. By using RB-IGBT, the series diodes may be avoided and hence the losses and complexity of the converter may be reduced [15].…”

“…However, further improvements in RB-IGBT technology is needed to reduce the switching losses because of the reverse recovery effects [16]. On the other hand, aside from the higher efficiency, IGCTs are known to be very reliable and rugged with respect to over current compared to IGBTs [17]. Hence, IGCTs may be the good choice for high power applications with low voltage and high current requirements.…”