DC motor H bridge current waveform

[anotherbrick]

hi dear forum members

my question in the picture

thank you

 

[barry]

Do you have a more detailed schematic showing values, gate-drive cat, etc?

 

[KlausST]

...and where exectly is the point of current measurement?

 

[anotherbrick]

thank you , diodes resistors caps are place holder in schematic real names and values different in physical circuit

 

[Easy peasy]

you are seeing the current flowing into the electro across the fets, when they turn off motor current flows into electro - and source current still flows into electro - but reducing . . . .

 

[anotherbrick]

thank you ,can you tell which route the current following when the PWM signal is low
which mos and which freewheeling diode

 

[barry]

you are seeing the current flowing into the electro across the fets, when they turn off motor current flows into electro - and source current still flows into electro - but reducing . . . .

If by “electro” you mean capacitor, then I agree. Which is why I asked to see a schematic to begin with…

 

[std_match]

Move the current probe so it only measures the current going to/from the MOSFETs.
I think that will be less confusing.
As you expect in post #1, when switching off MOSFETs 1 and 4, the current goes in MOSFETs 2 and 3 (body diode),
so the current to/from the MOSFETs will change polarity.

 

[Easy peasy]

If - in the real world - you had the electro on the LHS of the current probe in your sketch above, rather than across the H bridge ( where it is but you omitted it from your sketch ) then you would see your expected waveforms.