Usage

After Installation, the networks are trained from a dataset with motulator_gradnet.train_gradnet(), and the trained map is loaded and used in motulator as described in its documentation.

A dataset is an npz file with the complex arrays i_s_dq (stator current, A) and psi_s_dq (stator flux linkage, Vs) of the same shape, peak-valued space vectors in rotor coordinates. A dataset with spatial harmonics has also the arrays theta_m (electrical rotor angle, rad) and tau_m (electromagnetic torque per pole pair, Nm). The following example trains a flux linkage map from the measured dataset of a 5.6-kW PM synchronous reluctance machine in examples/datasets/:

import motulator.drive.gradnet as gn
from motulator.drive import utils

from motulator_gradnet import (
    PNormGradient,
    get_training_data,
    print_flux_map_errors_meas,
    train_gradnet,
)

# Base values of the machine, used to normalize the data
nom = utils.NominalValues(U=460, I=8.8, f=60, P=5.6e3, tau=29.7)
base = utils.BaseValues.from_nominal(nom, n_p=2)

# Train a flux map from every 10th data point and save it
dataset_path = "examples/datasets/baldor_meas.npz"
train_gradnet(
    dataset_path,
    base,
    is_flux_map=True,
    embed_dim=6,
    epochs=20000,
    subsample=10,
    activation=PNormGradient,
    save_model_path="flux_map.npz",
)

# The trained map is evaluated with motulator, without PyTorch
flux_map = gn.FluxMap(gn.load_gradnet("flux_map.npz"))
print(flux_map(5 + 8j))  # Flux linkage (Vs) at the current (A)

# Compare with the data points not used in the training
_, val_data = get_training_data(dataset_path, base, subsample=10)
print_flux_map_errors_meas(flux_map, val_data, base)

The map is used in the machine models and control systems of motulator through its parameter classes, e.g., SaturatedSynchronousMachinePars(n_p=2, R_s=0.63, psi_s_dq_fcn=flux_map). Complete examples, which also train current maps and maps with spatial harmonics, are in the example gallery, and simulation examples using the trained maps are in the documentation of motulator.