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IRS25091SPbF

A common problem in today’s high-power switching converters is the transient response of the switch node’s voltage as the power

switches transition on and off quickly while carrying a large current. A typical 3-phase inverter circuit is shown in Figure 11; here we

define the power switches and diodes of the inverter.

If the high-side switch (e.g., the IGBT Q1 in Figures 12 and 13) switches off, while the U phase current is flowing to an inductive load,

a current commutation occurs from high-side switch (Q1) to the diode (D2) in parallel with the low-side switch of the same inverter

Figure 11: Three phase inverter

Q1

ON

D2

Q2

OFF

DC+ BUS

DC- BUS

DC+ BUS

Q1

OFF

D1

D2

DC- BUS

Q2

OFF

Figure 12: Q1 conducting

Figure 13: D2 conducting

Also when the V phase current flows from the inductive load back to the inverter (see Figures 14 and 15), and Q4 IGBT switches on,

to the negative DC bus voltage.