Adding models to a test-project is easy
Electric motors require particularly fast controller interventions with short response times. These fast control cycles in turn require very rapid simulation models. To achieve this, parts of the simulation model are computed not on the LABCAR-RTPC simulation target, but directly on the ES5340 electric motor simulation board with FPGA (field programmable gate array) technology. With computing times of 850 ns, the ES5340 board supplies the required performance.
The FPGA models are coupled with models on the PC-based simulation target LABCAR-RTPC via the ETAS LABCAR-OPERATOR configuration and experimentation environment. This allows them to, for example, be embedded in the LABCAR-MODEL-VVTB complete vehicle simulation. In the case of lower requirements or for MiL/SiL applications, there are also models available that are computed exclusively on the LABCAR-RTPC.
Simulation models of PMSM electric motors for HiL tests
ETAS offers the following simulation models of PMSM motors:
- LABCAR-MODEL-PMSM (simulation model of a permanent magnet synchronous motor for HiL tests)
LABCAR-MODEL-PMSM (Simulation Model of PMSM Electric Motor for HiL Tests)
Flexibly adaptable simulation model for HiL tests
ETAS’s LABCAR-MODEL-PMSM model simulates a three-phase permanent magnet synchronous motor (PMSM) together with inverter and mechanics. Its features are designed for the testing and pre-calibration of ECU controllers and run directly on the real-time simulation target LABCAR-RTPC. In this way, it can be easily adapted to customer requirements with MATLAB®/Simulink®. The accuracy of LABCAR-MODEL-PMSM is sufficient for many fields of application.*
Balance between model runtime and accuracy
In developing the LABCAR-MODEL-PMSM model, developers could draw on a wealth of experience from working with electric motor ECUs. For this reason, the PMSM model realistically contains all the main physical effects required for reliable testing, such as the saturation and temperature effects of motor parameters. In addition, the simulation model calculates the power dissipation in the motor and inverter. The LABCAR-MODEL-PMSM model strikes a careful balance between this high accuracy and model runtime.
Using LABCAR operating software, it is very easy to couple the LABCAR-MODEL-PMSM model to other simulations in the context of co-simulations. This allows users to integrate the model into the complete simulation of a hybrid vehicle or the LABCAR-MODEL-VVTB complete vehicle simulation, for example.
Structure of the model
The LABCAR-MODEL-PMSM model consists of three distinct parts: the power stage/inverter, the PMSM itself, and the mechanical load.
The inverter is parameterized using typical variables such as switching times, polarity, and resistances of switches and diodes. For each switch, the error conditions “open” or “closed” can be parameterized. So-called free-wheeling, when all six switches are open, can also be simulated. In addition, the temperature-dependent power dissipation of ohmic components is also taken into account for the entire inverter. The inverter’s input circuit includes the battery’s internal resistance and the DC bus capacitor. In this way, the DC bus voltage can also be simulated.
The PMSM is parameterized using typical variables such as the number of pole pairs and the cogging positions. Further variables such as resistances, inductances, magnetic flux, and cogging torque can be changed at runtime. This ensures very precise simulation of the phase currents and electric moment. The PMSM model also takes into account the temperature-dependent power dissipation of ohmic components.
For the mechanical connection to the powertrain, the FPGA model contains a dual-mass spring-damper system. Parameterization is carried out using the typical variables: friction coefficient, moment of inertia for rotor and load, torsional stiffness, and damping. The powertrain’s load torque can be set and changed at runtime, or used for connecting to other models.
The simulation model’s most important output variables are either connected to another PC-based simulation model, or they are output directly as electrical signals via HiL hardware.
* For particular requirements relating to PWM (pulse-width modulation) signals and the simulation of error conditions in the IGBT (insulated-gate bipolar transistor), the LCM_PMSM5340_U1 (FPGA Inverter/PMSM Model for ES5340) model is available.