without HW, the answer ,as far as I know, is NO.
but for DC, you can use simple LPF (i.e., RC) to generate DC from PWM.
for AC, you can also play around LPF and PWM; however, I guess, freq. will be limited > several KHz (If you are not using 490Hz default PWM), also the wave form look rather saw tooth...
A clever summing network might be needed to add two signals.
Nahoona