So the question3 is: Do you know of a good tutorial/ manual to follow for the power loss calculation of a BLDC drive?īEMF reduces internal voltage thus torque reduces to 0 at full speed.Īlso.

Now I could start researching, but I fear that im gonna spend 5 hours on it and later find out, that the calculation does not fit for BLDCs. I have seen some power loss calculation in the manual for a drive made by texas instruments, but it was hard to follow because the terms are new to me. It seems like there are Mosfets and IGBT, also trapezoidal control for BLDC and sinusoidal for PMSM. Im fairly new to electronics and dont know where to start. Question2: Is there any BLDC with a given efficiency map out there? I would love to calculate the efficiency and compare it to some real experimental data (and share it with you ofc), but could not find anything on google myself Question1: Why does the torque constant have to be recalculated (scroll almost far bottom of the link)? Where does the given formula K_t_warm=k_t *(1+ magnet_temp_coeff *temp_difference) come from and why is it so similar to the heated resistor formula? Do you need to do this for brushless dc motor aswell? Now I want to proceed as stated here: Motor Calculations for Coreless Brush DC MotorsĬalculate P_loss from efficiency, use thermal equivalent circuit, calculate new heated R_ph-ph, recalculate power losses and new coil temperature iteratively. Looks like motor loosing efficiency because of intertial torque as a component of T_load and also cause of the inductivity L. U_terminal=(L/k_t)* dT/dt +(R_ph-ph/k_t) *T_load +I_o *R_ph-ph +k_emf *nĮfficiency=P_out/P_el=T *2 *pi *n/(U_terminal *I) with U_terminal from above, I=Io +T_load/k_t

U_terminal=L* di/dt +(I_o+ I_load)* R_ph-ph +k_emf *n Used equivalent circuit for DC motor as model for BLDC: Calculated torque and speed of the motor (robot arm swinging mass)

How to calculate motor winding data