FE-Simulation

Cogging (cogg_calc)

Parameter	Description	Default	Unit
speed	Speed		1/s
skew_angle	Skewing angle	0	deg
num_skew_steps	Number of skew steps	0
magn_temp	Magnet Temperature		°C
num_move_steps	Number of move steps
num_par_wdgs	Number of parallel coil groups	1
eval_force	Evaluate force	0
period_frac	Rotate Fraction of Period	1
vtu_movie	Create VTU files	False

Example:

simulation = dict(
  calculationMode="cogg_calc",
  magn_temp=60.0,
  num_move_steps=49,
  speed=50.0)

PM/Rel Machine Simulation (pm_sym_fast)

Parameter	Description	Default	Unit
speed	Speed		1/s
skew_angle	Skewing angle	0	deg
num_skew_steps	Number of skew steps	0
magn_temp	Magnet Temperature		°C
wind_temp	Winding Temperature	20	°C
num_move_steps	Number of move steps	49
num_par_wdgs	Number of parallel coil groups	1
eval_force	Evaluate force	0
current	Phase current		A (RMS)
angl_i_up	Angle I vs. Up	0	deg
optim_i_up	Optimize Current	0
phi_start	Start angle of rotation	0	deg
range_phi	Rotation angle	360/p	deg
explicit_mode	Deactivate rotation correction	0
plots	Create plots	[]
airgap_induc	calculate airgap induction	False
period_frac	Rotate Fraction of Period	1
calc_noload	Calculate no load	1
magnet_loss	Extended magnet loss calc (IALH)	False
poc	Current shape definition	(none)
vtu_movie	Create VTU files	False

Note

plots is a list of field_lines or color_gradation plots to be created after the calculation. Possible values ‘field-lines’, ‘Babs’, ‘Br’, ‘Bx’, ‘By’, ‘Br’, ‘Bt’, ‘Habs’, ‘Hx’, ‘Hy’, ‘Hr’, ‘Ht’ ‘demag’, ‘ecurr’, ‘ecloss’, ‘relperm’, ‘Wm’, ‘Bdev’, ‘Vpot’. (See http://script.profemag.ch/ColorGrad.html) added in version 0.0.16. The value types can be simple strings or list with name and min/max range.

Example:

simulation = dict(
  calculationMode="pm_sym_fast",
  wind_temp=60.0,
  magn_temp=60.0,
  current=50.0,
  speed=50.0,
  plots=['field_lines', ['Babs', 0.0, 2.5]])

Note

If airgap_induc is True the induction in the airgap is calculated after the simulation returns. The values can be read with the method read_airgap_induc() of call Femag.

Parameter	Description	Unit
Baml	Amplitude of base harmonic	T
phi0	Phase angle of base harmonic	rad
pos	Position	° or mm
B	sampled values	T
B_fft	Values of base harmonic	T

Note

The poc class is used to define current shape: sin, rec, har, hsp, fun

Parameter	Description	Unit
pole_pitch	pole pitch
key_winding	list of key ids

Short circuit calculation (shortcircuit)

The short circuit calculation is executed subsequentially to a pm_sym_fast simulation if shortCircuit is set True. (version added 0.9.30). The results are included in scData dict of bch

Parameter	Description	Default	Unit
shortCircuit	run short circuit calc if True
l_end_winding	winding inductance	0	H
l_external	External inductance	0	H
sc_type	type of short circuit (3-phase)	3
simultime	Simulation time	0.1	s
initial	Initial condition 1: noload 2: load	2
allow_demagn	Allow Demagnetisation:1:yes; 0:no	0
sim_demagn	Simulate Demagnetisation:1:yes; 0:no	0

Example:

pmRelSim = dict(
   angl_i_up=-39.3,
   calculationMode="pm_sym_fast",
   wind_temp=60.0,
   magn_temp=60.0,
   current=76.43,
   period_frac=6,
   speed=50.0,
   shortCircuit=True,
   l_end_winding=0,
   l_external=0,
   sc_type=3,
   initial=2,
   allow_demagn=0,
   sim_demagn=1)

r = femag(machine, pmRelSim)

print('Torque [Nm] = {}'.format(r.machine['torque']))
print('''
  Short Circuit    Current         Torque
    Peak       iks {2:8.1f} A  tks {3:8.1f} Nm
    Stationary ikd {0:8.1f} A  tkd {1:8.1f} Nm

  peak winding currents {4}
'''.format(r.scData['ikd'],
           r.scData['tkd'],
           r.scData['iks'],
           r.scData['tks'],
           r.scData['peakWindingCurrents']))

fig, ax = plt.subplots()
femagtools.plot.transientsc(r)
plt.show()

SM Machine Simulation (pm_sym_f_cur)

Parameter	Description	Default	Unit
speed	Speed		1/s
skew_angle	Skewing angle	0	deg
num_skew_steps	Number of skew steps	0
wind_temp	Winding Temperature	20	°C
num_move_steps	Number of move steps	49
num_par_wdgs	Number of parallel coil groups	1
eval_force	Evaluate force	0
current	Phase current		A (RMS)
nload_ex_cur	No-Load excitation current	0	A
load_ex_cur	Load excitation current	0	A
angl_i_up	Angle I vs. Up	0	deg
optim_i_up	Optimize Current	0
phi_start	Start angle of rotation	0	deg
range_phi	Rotation angle	360/p	deg
explicit_mode	Deactivate rotation correction	0
plots	Create plots	[]
airgap_induc	calculate airgap induction	False
period_frac	Rotate Fraction of Period	1
vtu_movie	Create VTU files	False

Ld-Lq Identification (ld_lq_fast)

Parameter	Description	Default	Unit
speed	Speed		1/s
skew_angle	Skewing angle	0	deg
num_skew_steps	Number of skew steps	0
magn_temp	Magnet Temperature		°C
num_move_steps	Number of move steps
num_par_wdgs	Number of parallel coil groups	1
eval_force	Evaluate force	0
i1_max	Max. phase current		A (RMS)
beta_min	Min. Beta angle		deg
beta_max	Max. beta angle		deg
num_cur_steps	Number of current steps
num_beta_steps	Number of beta steps
period_frac	Rotate Fraction of Period	1

Example:

simulation = dict(
  num_move_steps=25,
  calculationMode="ld_lq_fast",
  magn_temp=60.0,
  i1_max=150.0,
  beta_max=0.0,
  beta_min=-60.0,
  num_cur_steps=3,
  num_beta_steps"=4,
  speed=50.0)

Psid-Psiq Identification (psd_psq_fast)

Parameter	Description	Default	Unit
speed	Speed		1/s
skew_angle	Skewing angle	0	deg
num_skew_steps	Number of skew steps	0
magn_temp	Magnet Temperature		°C
num_move_steps	Number of move steps
num_par_wdgs	Number of parallel coil groups	1
eval_force	Evaluate force	0
maxid	Max. Amplitude Id current		A
minid	Min. Amplitude Id current		A
maxiq	Max. Amplitude Iq current		A
miniq	Min. Amplitude Iq current		A
delta_id	Delta of Id current steps		A
delta_iq	Delta of Iq current steps		A
period_frac	Rotate Fraction of Period	1

Example:

simulation = dict(
  num_move_steps=25,
  calculationMode="psd_psq_fast",
  magn_temp=60.0,
  maxid=0.0,
  minid=-150.0,
  maxiq=150.0
  miniq=0.0,
  delta_id=50.0,
  delta_iq=50.0,
  speed=50.0)

PM/Rel Torque Calc (torq_calc)

similar to pm_sym_fast without noload calc (Note: requires a correct Poc)

Parameter	Description	Default	Unit
speed	Speed		1/s
skew_angle	Skewing angle	0	deg
num_skew_steps	Number of skew steps	0
magn_temp	Magnet Temperature		°C
wind_temp	Winding Temperature	20	°C
num_move_steps	Number of move steps	49
num_par_wdgs	Number of parallel coil groups	1
current	Phase current		A (RMS)
poc	Current shape definition	(none)
angl_i_up	Angle I vs. Up	0	deg

Example:

simulation = dict(
  calculationMode="torq_calc",
  wind_temp=60.0,
  magn_temp=60.0,
  current=50.0,
  angl_i_up=0.0,
  speed=50.0)

Axial Flux Machine (torq_calc)

Axial flux machines are split into concentric slices each simulated as a linear machine.

Example:

afpm = femagtools.machine.afpm.AFPM(workdir, magnetizingCurves='.',
          magnetMat=magnetMat, condMat='')

simulation = dict(
    angl_i_up=0.0,
    calculationMode="torq_calc",
    wind_temp=90.0,
    magn_temp=90.0,
    current=100,
    speed=12500/60)

engine = Engine()
num_slices = 3
r = afpm(engine, machine, simulation, num_slices)

FE-Simulation with existing model

FE calculations can be executed for existing models also. Since Femag Rel 8.3 there is no need to fully specify the machine model:

machine = "PM 270 L8"

workdir = os.path.join(
  os.path.expanduser('~'), 'femag')

femag = femagtools.Femag(workdir)

simulation = dict(
  angl_i_up=-38.7,
  calculationMode="pm_sym_fast",
  magn_temp=60.0,
  num_move_steps=25,
  speed=50.0,
  wind_temp=60.0,
  current=108.0)

r = femag(machine, simulation)

For older FEMAG versions the minimal data is:

machine = dict(
    name="PM 130 L4",
    lfe=0.1,
    poles=4,
    outer_diam=0.13,
    bore_diam=0.07,
    airgap=0.001,

    stator=dict(
        num_slots=12,
        num_slots_gen=3,
        mcvkey_yoke="dummy"
    )
)