Sizing the drive system - Propulsion Systems for Hybrid Vehicles - page 180

Table 4.12 (Continued)

Symbol Acronym Description Date

invented

Invented
by

Developed
by

K

GTO Gate turn-off

thyristor

1970 GE RCA,

Toshiba,
Siemens

G

A

SIT Static induction

transistor

1975 Japan Tokin

C

IGBT Insulated gate

bipolar
transistor

1982 GE GE/Harris,

Motorola,
others

G

E

SITh Static induction

thyristor

1986 Japan Japan

A

MCT MOS controlled

thyristor

1988 GE Harris

G

EST/ETO Emitter switched
thyristor, now
called emitter
turn-off
thyristor

1990 NCSU PSRC,

Infineon

K

ACBT Accumulation

channel (driven)
bipolar
transistor

1995 NCSU PSRC

C

CSTBT Charge stored

trench bipolar
transistor

2000 IR IR, others

G

E

NCSU: North Carolina State University; PSRC: Power Semiconductor Research Center.

4.3.3 Ripple capacitor design
Power electronic inverters may have as much as 60% of their volume taken by the
dc link capacitors needed for bypassing the load ripple currents. The dc bus capa-
citor is sized not so much for energy or hold-up time, but thermally by the rms
ripple current it must circulate. First-principle understanding of inverters states that
no energy storage occurs in the inverter, only switching elements. However, the
high frequency currents generated by the inverter switching are sourced by the dc
link capacitor, particularly if the battery is located far from the inverter. In hybrid
propulsion systems when the inverter is required to be packaged within 1 m of the
M/G to minimize EMI, it is the bus capacitors that source and sink the switching
frequency components. The battery in effect keeps the capacitor bank charged by
supplying the real power demand.