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TIDM-HV-1PH-DCAC: TIDM-HV-1PH-DCAC

Bo Yang
Prodigy 10 points
Part Number: TIDM-HV-1PH-DCAC

Tool/software:

Hi TI Tech Expert,

I am running some of tests on TIDM-HV-1PH-DCAC eval system. I ran this system as voltage source inverter in Open Loop mode. The system works as expected. However, I noticed that there are spikes on all 4 gate control signals (i.e. Q1.PWM, Q2.PWM, Q3.PWM, and Q4.PWM). I have a big concern on these spikes that may create the "shoot through" condition and damage the switching devices (MOSFET or IGBT). Can anyone explain why these spikes are present and how to suppress them if possible. The attached picture show the spikes probed on TP15 (ch2), TP16 (ch3), and TP20 (ch4) on the eval board. Thanks for any reply.

  • 0
    TI__Expert 4165 points

    Hello Bo

    Can you confirm if these noise are not picked by the probe? Are you using differential probe? Can you try measuring one Gate driver output at a time and check if noise is still there?

    Thank you 

    Amir Hussain

  • 0
    Prodigy 10 points

    Hi Amir,

    Thanks for your quick reply.

    I have used the differential probe to measure the output (i.e. Q1 PWM) of the driver controlling A leg of the bridge. The spikes are still there. Please see attached pictures for the spikes and the setup of differential probes to measure Q1 PWM output.

  • 0 in reply to Bo Yang
    Prodigy 10 points

    attached picture here:

    I used the differential probe on ch1 and single end probe on ch2 because I found only one differential probe. Thanks.

  • 0 in reply to Bo Yang
    TI__Expert 4165 points

    Hello Bo

    Thank you for the further information. I could not find the root cause yet myself. I will consult the hardware expert for more info and let you know. 

    I see the spikes are in the order of 100 of nano second. Do you see any current spike from the DC source. Do you also see increase in the magnitude of the spikes as you increase the DC input voltage? 

    Thank you 
    Amir Hussain

  • 0 in reply to Amir Hussain
    Prodigy 10 points

    Hi Amir,

    I tested the inverter system with different input DC voltages (200V and 300V). The spikes on the gate control signal Q1 PWM has no change in terms of amplitude. I don't have the current probe so can't check if there is current spikes on DC source. The picture on left has 200V of input DC. One on right has 300V DC. Thanks for your reply. 

  • 0 in reply to Bo Yang
    TI__Expert 4165 points

    Hi Bo

    Please check the current. If it does not have any spike, I would recommend to go ahead with you experiments.

    Thank you 

    Amir Hussain

  • 0 in reply to Amir Hussain
    Prodigy 10 points

    Hi Amir,

    I checked the current spikes on DC source line and didn't see any spikes when the gate (Q1) signal has spikes. Ch2 is the current measurement on DC source. Now I feel more comfortable with more testing on this inverter system. Appreciate your helps.

  • 0 in reply to Bo Yang
    TI__Expert 4165 points

    Great. Good Luck for further testings.

    Thanks

    Amir