HIL Simulation for Vehicle Traction Motors

Controller tests for electric motors at signal level

At the signal level, the test system is connected to internal interfaces of the electric drive control unit, i.e., to the signals of the gate drivers and to the signals of the current transducers. Any power electronics devices are disconnected from the device under test. This approach enables maximum scalability and full model access. This example describes FPGA-based simulation with SCALEXIO. FPGA-based simulation is typically used if very high computation speed is needed.
If you do not need high computation speed, you can also perform processor-based electric motor simulation tests with SCALEXIO. The motor and inverter models are then computed on the SCALEXIO Processing Unit.

Application Areas

  • Testing electric motor ECUs for powertrains, e.g.:
    • Hybrid and battery electric vehicles
    • Fuel-cell vehicles
  • Testing all other kinds of electric motor controllers that require high precision for simulating higher fundamental frequencies and stability
  • Developing electric powertrains
  • Developing off-highway vehicles

Key Points

  • Very high oversampling rate according to the PWM switching frequency
  • No PWM synchronization necessary
  • Simulation of current ripples (PWM effects)
  • Fast signal computation with user-programmable FPGA
  • Motor and inverter models on FPGA
  • Ready-to-use open FPGA models for all common motors and sensors
  • Nonlinear effects by means of FEM-based parameterization (e.g., JMAG)
  • Sample times of < 500 ns for highest simulation quality
  • FPGA-based acquisition of gate driver signals
  • FPGA-based simulation of current and position sensor signals
  • Convenient graphical system configuration

The DS2655 FPGA Base Board has been designed for applications that require very fast, high-resolution signal processing, such as electric motor HIL simulation. It includes a powerful, freely programmable field-programmable gate array (FPGA), the Xilinx Kintex-7 160T or the Kintex-7 410T. To include I/O channels, you can connect up to five I/O modules to the board. Together with the XSG Electric Components Library, the DS2655 provides the fast reaction times required for simulating electrical machines in closed-loop operation with a controller.

For expanding the I/O channels of the DS2655, there are two I/O modules: the DS2655M1 Multi-I/O Module and the DS2655M2 Digital I/O Module. They provide the high number of digital and analog I/O channels needed for applications such as electric drives.

Software-Based FPGA Configuration

The SCALEXIO system for HIL simulation provides a wide range of I/O hardware, which enables you to connect various converter and motor types. You can program applications for the DS2655 FPGA Base Board's FPGA with Xilinx System Generator, and the RTI FPGA Programming Blockset enables the I/O and processor access. The programs can be downloaded to the FPGA via ConfigurationDesk.
You can test the program in an offline simulation before implementing it on the real-time hardware. This lets you react flexibly to new requirements, such as new interfaces or having to accelerate the execution of submodels.

Electric motor control applications that demand very high precision and correspondingly high sampling rates are best simulated on field-programmable gate arrays (FPGAs). The XSG Electric Components Models (closed-loop simulation components) are implemented as Xilinx System Generator (XSG) models that run on a dSPACE DS5203 FPGA Board (PHS-bus systems) or DS2655 FPGA Base Board (SCALEXIO), so you can use the same workflows for controller development and testing. This makes it possible to perform closed-loop simulations of electric devices and their controls at very high sampling rates in real time.

Direct FPGA I/O Access

In addition to the plant models, for the DS5203 and DS2655 boards the XSG Electric Components Library provides enhanced I/O functions from the contained XSG Utils Library, e.g., for timing analyses and digital input source capturing. The XSG Electric Components Library and the DS5203/DS2655 boards can be used together for E-motor simulation at both the signal and the power level.

Components and Characteristics

  • Permanent magnet synchronous motor (PMSM)
  • Brushless DC motor (BLDC)
  • Advanced inverter model supporting the discontinuous conduction mode (DCM)
  • Asynchronous squirrel cage induction motor
  • Resolver, sine, TTL, and Hall encoders
  • XSG Electric Components Library containing the XSG Utlis Library, which offers additional functionality
  • Delta-star connection configurable for three-phase motor models

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