TMDSHVMTRPFCKIT: TMDSHVMTRPFCKIT

Part Number: TMDSHVMTRPFCKIT

Hi,

I try to drive my 3 phase PMSM using TMDSHVMTRPFCKIT with MCU f28035.

As I know, there are three ways to supply DC bus voltage for 3 phase inverter stage. (1. DC supply / 2. AC entry / 3. AC entry + PFC)

When I supply DC bus voltage directly by using DC power supply, there was no problem and PMSM was drived well.

However, when I supply DC bus voltage through AC power entry with 220 VAC wall supply, the problem happened.

I don't use PFC stage so that BS1 and BS5 were connected each other and other circuits including MCU were not powered yet.

When I turned switch of power strip on to supply 220 VAC from wall to the board, some spark and sound with a pop occurs in my board.

After this accident, I saw that AC power supply is recommended through isolator and variac as shown in the following figure, but I didn't at that time.

So, my question is

1. How can I supply DC bus voltage safely through AC power entry with AC voltage?

2. If I use isolator and variac, then can I expect to supply DC bus voltage safely?

3. What is the roles of isolator and variac?

4. Please, give me some recommendation for isolator and variac.

I will be waiting for your answer.

Thank you.