How to Simulate a Drive with a Machine

Prerequisites

Procedure

Different modeling resources within the FPGA design are used to simulate different parts of the electrical model. For example, in the case of a drive system, the power electronics circuit containing linear elements is simulated using the eHS Solver, whereas the machine configuration is simulated with a Machine Model (see image below). Due to this inherent decoupling of the two parts of the simulation, additional considerations must be made when simulating a drive coupled to a machine.

Interface Requirements to Couple a Drive and a Machine

To couple a drive circuit with a machine, specific sets of Sources and Measurements must be added to the circuit model. Typically, it is important to include the following interface elements:

Measurements for the phase voltages that will be output from the drive model (eHS) and fed into the machine model
Sources for the currents that will be output from the machine model and injected into the drive model (eHS)
RC snubbers to compensate for the decoupling of the two solvers on the FPGA. Please see Tuning the Snubber Values for more information.

A set of Template Circuits is available in the Examples directory to serve as a starting point when designing a circuit model for machine drive.

Configuring the Mapping between the Drive and the Machine

To map the interface Sources and Measurements of the circuit to the Machine Model:

Follow the steps in How to Add a Circuit Model to the System Definition to load the circuit model into the project.
In the VeriStand System Definition, navigate to the Machine Model configuration page.
Under Input Mapping Configuration, map the appropriate voltage Measurements of the circuit to the inputs of the machine model. The available machine inputs may differ depending on the selected Machine Model. Refer to the Template Circuits for examples of connections made to different machines.

Navigate to the Sources configuration page.
Map the outputs of the machine model to the corresponding current sources in the circuit model. The available machine outputs may differ depending on the selected Machine Model. Refer to the Template Circuits for examples of connections made to different machines.

Tuning the Snubber Values

An RC snubber is often used to stabilize the decoupling of two solvers on the FPGA (e.g. eHS solver & a machine). Ideal snubber values can be calculated based on the following parameters of the simulation:

Nominal speed of the machine being simulated
Power rating of the machine between simulated

For details on how to select a snubber value for your simulation, please contact OPAL-RT Technical Support.