Electric Motor Drives Modelling And Analysis Krishnan -

| Feature | PMSM | BLDC | |---------|------|------| | Back-EMF | Sinusoidal | Trapezoidal (flat top 120°) | | Current waveform | Sinusoidal, in phase with BEMF | Rectangular, 120° conduction | | Torque ripple | Low | High at commutation | | Control | FOC or ( i_d=0 ) | Hall sensors + six-step |

Crucially, Krishnan bridges the analog world to the digital. He discusses the effect of sampling rates, quantization errors, and computational delay in digital signal processors (DSPs) — a topic often ignored in purely theoretical texts. Electric Motor Drives Modelling And Analysis Krishnan

For each drive, he derives:

[ \frac\omega_m(s)V_a(s) = \fracK_t(L_a s + R_a)(J s + B) + K_t K_b ] | Feature | PMSM | BLDC | |---------|------|------|

Derivations for DC, induction, and permanent magnet motors from first principles. in phase with BEMF | Rectangular