Generate Feed-Forward Flux Parameters

Step 2 of 3 in Generate Optimal Current Controller Calibration Tables for Permanent Magnet Synchronous Motors

This example shows how to create lookup tables for an interior permanent magnet synchronous motor (PMSM) controller that characterizes the d-axis and q-axis flux as a function of d-axis and q-axis currents.

To generate the flux parameters for the Flux-Based PM Controller block, follow these workflow steps.

Step 1: Load and Preprocess Data

Load and preprocess this nonlinear motor flux data from dynamometer testing or finite element analysis (FEA):

• d- and q- axis current

• d- and q- axis flux

• Electromagnetic motor torque

Import and preprocess the raw PMSM data from an xlsx file captured from a dynamometer or another CAE tool.

fileName = "PMSM_150kW.xlsx";

opts = detectImportOptions(fileName);

% read units if they are defined in the second row
if opts.DataRange=="A3"                 
    opts.VariableUnitsRange = "A2";
end

rawData = readtable(fileName, opts);

Load the data columns.

lambda_d = rawData.Psi_d;
lambda_q = rawData.Psi_q;
id = rawData.I_d;
iq = rawData.I_q;

Step 2: Generate Evenly Spaced Data

The raw current and flux tables are recorded in a single column format. Convert them into evenly spaced data matrices using 2-D interpolation.

Set the spacing for the table rows and columns.

flux_d_size = 51;
flux_q_size = 51;

Use interpolation to get higher resolution.

id_new = linspace(min(id),max(id),flux_d_size);
iq_new = linspace(min(iq),max(iq),flux_q_size);
currentBreakpoints = {id_new,iq_new};

Visualize the Flux Surfaces

The d-axis flux, λd, is a function of d-axis current, Id, and q-axis current, Iq.

lambda_d_new = fitlookupn(currentBreakpoints,[id,iq],lambda_d,ShowPlot=true);
title("Flux d [Wb]");
xlabel("Id [A]")
ylabel("Iq [A]");

The q-axis flux, λq, is a function of d-axis current, Id, and q-axis current, Iq.

lambda_q_new = fitlookupn(currentBreakpoints,[id,iq],lambda_q,ShowPlot=true);
title("Flux q [Wb]");
xlabel("Id [A]")
ylabel("Iq [A]");

Step 3: Set Block Parameters

Set these Flux-Based PM Controller block parameters to the values assigned in the script.

Vector of d-axis current breakpoints, id_index

id_index=id_new;

Vector of q-axis current breakpoints, iq_index

iq_index=iq_new;

Corresponding d-axis flux, lambda_d

lambda_d=lambda_d_new;

Corresponding q-axis flux, lambda_q

lambda_q=lambda_q_new;