## Electronics

Topics relate to HFSS, Maxwell, SIwave, Icepak, Electronics Enterprise and more

#### Radial and Tangential Magnetic force on rotor of a PMSM

• Abdur Rahman
Subscriber

Hi,

I am trying to obtain unbalance magnetic force acting on the rotor of a PMSM. Could anybody suggest me how can I obtain radial and tangential force acting on the rotor of a PMSM? Can I get it directly using field calculator, if so, please explain step by step? Also, please explain how can I write the Maxwell stress tensor formula, as shown in the figure, in the field calculator.   Thanks.

Fx can also be expressed as eqn (4)

• DELI
Ansys Employee

hi, you can use field calculator to create named expression for radial and tangential force.

Br=ScalarX(ToCylindrical(,offset<0mm, 0mm, 0mm>))

Bt=ScalarY(ToCylindrical(,offset<0mm, 0mm, 0mm>))

mu0=1.25664E-06

Fmst_r= /(-(*(Br, Br), *(Bt, Bt)), *(mu0, 2))

Fmst_t= /(*(Br, Bt), mu0)

• GLUO
Ansys Employee

Hello,

Please use the radial flux density to get the radial force.

For radial flux density in field calculator:

Input > Quantity > B
Vector > Scal? > ScalarX
Input > Function > Scalar > PHI
Scalar > Trig > Cos
General > *
Input > Quantity > B
General > Smooth
Vector > Scal? > ScalarY
Input > Function > Scalar > PHI
Scalar > Trig > Sin
General > *
General > +
Select Add and set the name of expression as B_radial

• GLUO
Ansys Employee

You can also rightclick the design name to enable harmonic force calculation. The tangential and the radial force will be ready in the report. MST is defined as Fmst_r=(Br^2-Bt^2)/(2*mu0), Fmst_t=Br*Bt/mu0.

GL