ETAS ES5340.2, User Manual, Page: 59 / 120

ES5340.2 Electric Drive Simulation Board - User’s Guide 59
ETAS FPGA Models
4.2 Induction Machine (IM) Model
The FPGA model of an induction machine (IM) is build up out of a three-phase
inverter and an induction machine including mechanics. Many experiences out of
the development of electrical drives took influence on this model. So it is able to
simulate the essential physical effects needed for reliable tests, like temperature
effects or saturations of motor parameters. It is build up according to a balanced
behavior between runtime and accuracy.
Within the whole model calculations are made with floating-point arithmetic
which results in a very high accuracy over the whole parameter- and simula-
tion-area. With the FPGA based model the model step sizes are once more
reduced drastically to 850 ns – according to about 10 μs of a related model exe-
cuted on a real-time PC. This makes it possible to detect a PWM signal via Hard-
ware with a high accuracy and directly use this signal in the inverter model.
The model consists of three parts:
• Inverter
• Induction machine (IM)
• Mechanical load.
Fig. 4-3 The modeled system
Inverter Model
The parameterization of the inverter is done by using typical values like switching
times, polarity or resistances of switches and diodes. For every switch it is possi-
ble to parameterize the failure states “Open” and “Closed”. Also the “free-
wheeling” can be simulated, when all six switches are opened.
For the whole inverter also the temperature dependent power loss of ohmic
components is considered. The inputs of the inverter include the inner resistance
of the battery as well as the intermediate circuit capacitance, which makes it
possible to simulate the intermediate circuit voltage.
6 x
PWM Gate Signal
Vehicle Power Stage
phi_mech
omega_mech
load torque
Induction Machine
phi_elec
3 x
U_ind P_loss
omega_elec
torque_elec
U_DC
3 x
U_phase
6 x
U_switch
6 x
I_element
I_DC
U_Batt0
E-Motor
3 x
I_stator
3 x
I_rotor
I_Batt0 I_DC