CSIs

Question 1

What do you need to remember when putting Iref into an equation (e.g. one with Iref/Id in it)

Answer 1

Iref in that equation is the PEAK value

Question 2

What is the order of the vectors for a given sector

Answer 2

Ik, I(k+1), I0

Question 3

How do you choose which pair of devices should be on to make the 0 vector?

Answer 3

One device will have been on for BOTH of the Ik and I(k+1) vectors. That device will stay on for the 0 vector time and the other device in that leg will also turn on in order to short circuit the source

Question 4

What are the 3 switching constraints of CSIs

Answer 4

1) If only 1 device is on, the conduction path is broken. If this happens, Ld causes a voltage spike which can damage devices
2) If >2 devices are on, output current is defined by the LOAD and not by switching.
3) If 2 switches in the same leg are on, the source is bypassed

Question 5

How do you show that the max amplitude of Iref is Id

Answer 5

Sub in the To value that makes Iref the largest - that value is 0

Question 6

What is the purpose of a 3 phase capacitor on a CSI

Answer 6

The load has inductance therefore stores energy
At turn off, current will not fall to 0 instantly
Voltage spike, can damage devices
Therefore put capacitors there to provide discharge path