Hello
I am using 6 channels of a timer to generate PWM waveforms at 16KHz
These drive 6 MOSFETs.
I have a sine table of 32 entries
0 25 49 73 96 118 139 159 177 193 208 220 231 239 245 249 250 249 245 239 231 220 208 193 177 159 139 118 96 73 49 25
I have a bridge inverter built as shown below
R Y B
R^ Y^ B^
Upon overflow of the 16KHz timer i refresh the overflow values for each channel
like this R = Y^ , Y = B^ , B = R^
I have an offset for 120° phase shift between these , which basically are the
index + 22 (120°)
index +12 (240°)
index (0)
But this is not working.
I get cross conduction in all vertical limbs.
How is this usually done? I understand that the R^ must be out of phase with R and so on but that to happen shouldn't Y^ =R ?
I have looked and looked at various APP notes from Microchip, AVR and various tutorials but am unable to understand this concept.
Please someone throw some light
Help needed desperately