Sinusoidal PWM modulation types

[120vjohn]

There are tho main types of sinusoidal pwm, bipolar spwm and unipolar spwm. for single phase sinusoidal inverter, for there phase only bipolar is available.
Both of them can be produced with EG8010/EGS002 ASIC/ APP board (china), via a selection pin, ground unipolar, 5v bipolar, or write it in EG8010`s configuration registry. it comes configurated as unipolar spwm.
Despite it`s higher efficiency unipolar is horrible in matter of common mode harmonics, bipolar is smooth, common mode is neutral in respect with dc bus bars, it not radiate harmonics.
Common mode harmonics are radiated as electric and magnetic field and hum audio system, worse they may affect nervous system and health status, for this reason I use only bipolar spwm, efficiency difference is minor, bipolar can reach 96% under full load on silicon carbide, unipolar 98-99%
Scope sheets: bipolar and unipolar spwm on EGS002 with silicon carbide switches.

 

[mopat]

Okay 120vjohn, was there a question in the post?

 

[120vjohn]

No question, only presentation, these scope sheets are on my DIY inverters, I try to give you an awareness about what may hide behind sinusoidal inverter, That square wave radiated in your wiring and surrounding space is not good, It may affect your healh worse than grid.
I use only bipolar first image, unipolar jammed my washing machine controller with bipolar it works fine, for years.
Refference in these scope sheets is dc bus ground (negative ) to each output after filter: channel1 red channel 2 yellow.
I hope you find it useful.