Power electronics for very high power applications

Abstract

As we prepare to enter the 21 st Century we stand on the threshold of a Power Electronics Revolution. The last 50 years have seen the growth of power conversion to the point at which today about 15% of the electric power produced undergoes some form of electronic conversion. However, most of this occurs at the "consumer end" of the supply chain from battery chargers to locomotives. Although HVDC transmission has exploited line-commutated power electronics for the past three decades, it is the 1990s which have witnessed the commissioning of self-commutated power electronics at the transmission level. Developments in semiconductors and their packaging technology will drive power electronics into distribution applications as device efficiency and reliability increases whilst the cost of the switched megawatt falls. The key semiconductors enabling this predicted transition will be reviewed and the anticipated demands of system builders on device suppliers discussed.

Novel Application of PWM Switching for DC Traction Circuit Breakers

“…HIGH POWER SEMICONDUCTORS Much work in comparing power semiconductors for use in varies applications has contributed to categorizing them in the fields for which they are generally most suitable. When it comes to the employment of semiconductors in the high power field and especially where on-off control in DC systems is a major factor the choice can normally be narrowed down to two devices [2]. The first device the IGCT is from the thyristor family while the other, the IGBT is from the transistor family.…”

“…The first device the IGCT is from the thyristor family while the other, the IGBT is from the transistor family. IGCTs and IGBTs generate the same losses during turn-off however the turn-on losses for IGCTs is considerable lower than IGBTs and may often be regarded as negligible due to their regenerative turn-on nature [2]. The IGCT being based on a thyristor structure has less than half the conduction losses for devices based on a transistor structure.…”

“…In summary the low conduction losses, low switching losses and the good high power handling capability of the IGCT makes it a good choice for use as a solid state circuit breaker. Considering the loop equation (2) V(o) = iR + Ldi/dt (2) and that the inductor prevents a sudden change in current it is seen that the initial rate of change of current is determined by…”

“…Once the breaker finally opens the energy stored in the inductor circulates a current through a FWD and an energy dissipation resistor for approximately 30 milliseconds. It is envisaged that this energy be dissipated in a resistor similar to that suggested in IGCT voltage source inverter topologies [2]. Due to the severe fault the load voltage is seen to have collapsed placing the entire source voltage essentially across the rectifier and the breaker.…”

Research of DC-DC power supply for IGCT gate unit

“…In the next year, German applied a more mature IGCT technology in their second Electric Power Network Connecting System in Bavaria. Nowadays, IGCT is increasingly applied in Static Var Generator (SVG), Static Var Compensation Equipment (SVC), Management Energy of Super conduction Storage System, VVVF, DC High Voltage Power Transmission [4] [5].…”