Single-Shunt Current Sensing — ADC & Modulation-Index Calculator

Interactive companion to “Acquisition-Time Limited Modulation in Single-Shunt Current Reconstruction for PMSM FOC”. The usable modulation index is set by the analog acquisition budget t_req = t_acq + t_blank + t_margin and the PWM period T_sw = 1/f_sw, not by ADC throughput.

Single-shunt m_max (full-angle)
—
d_max,SS—
m_min,SS (existence)—
blind half-angle @ m—
Budget
t_acq = ADC + op-amp—
t_req—
T_sw—
dual-shunt m_max—
d_max,dual—

m_max vs switching frequency (current t_req)

Solid = single-shunt full-angle bound; dashed = dual-shunt bound. The vertical marker is the selected f_sw.

Reference-vector plane & blind zones

blind half-angle—
measurable fraction / sector—
Va/Vb/Vc (red/green/blue) are the instantaneous phase-voltage vectors at angle θ; their Clarke sum is Vref (white). Inner circle = linear limit (m = 1); purple dashed = operating radius m; red wedges = blind zones where one active-vector dwell < t_req.

SVM duty cycles vs angle

Inverter gate signals & sampling points — one PWM period (at θ)

V1 window (t1)—
V2 window (t2)—
required t_req—