.Spot.DrivesDC.Partials.Synchron3rd_bldc

Information

The model is valid for permanent magnet (excite=2) machines.

For rectangular voltage without additional PWM the only degree of freedom is the voltage phase. It is chosen such that the d-axis current (magnetising current) is zero i_s[1] = 0.
Under theese assumptions the torque-speed characteristic is different from that of a DC-machine. In order to obtain a 'true' DC-characteristic with linear dependence of torque and i_s[2] from w_el, a second degree of freedom is needed.

Example using 'average' inverter (approximation of rectangle by its fundamental)
  v_sd = -w_el*c.L_s[2]*i_s[2]/((4/pi)*sin(width*pi/2)*par.V_nom);
  v_sq = 1;
  uPhasor[1] = sqrt(v_sd*v_sd + v_sq*v_sq);
  uPhasor[2] = atan2(v_sq, v_sd);

For reluctance (excite=3) machines psi_e is replaced by a desired magnetising current in d-axis i_sd.

  uPhasor[2] = atan2(c.R_s*i_s[2] + w_el*c.L_s[1]*i_sd, c.R_s*i_sd - w_el*c.L_s[2]*i_s[2]);
Using a pu-current i_sd_pu we obtain
  uPhasor[2] = atan2(c.R_s*i_s[2] + w_el*c.L_s[1]*i_sd, (par.V_nom/(c.omega_nom*c.L_s[1]))*i_sd_pu - w_el*c.L_s[2]*i_s[2]);

More information see Partials.Synchron3rdBase.


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