"""
2.2-kW IM, diode bridge, V/Hz control
=====================================

This example simulates pure open-loop V/Hz control of a 2.2-kW induction machine (IM)
drive, fed from a six-pulse diode bridge. The diode bridge is supplied from a stiff grid
through an AC choke.

"""

# %%
from math import inf, pi, sqrt

import matplotlib.pyplot as plt

import motulator.drive.control.im as control
from motulator.common.model import CompositeModel, DCBus, Simulation, ThreePhaseSource
from motulator.common.utils import complex2abc
from motulator.drive import model as drive_model
from motulator.drive import utils as drive_utils
from motulator.grid import model as grid_model

# %%
# Compute base values based on the nominal values.

nom = drive_utils.NominalValues(U=400, I=5, f=50, P=2.2e3, tau=14.6)
base = drive_utils.BaseValues.from_nominal(nom, n_p=2)

# %%
# Configure the system model. The diode bridge and the inverter share the DC bus, and
# their models are combined into a composite model.

dc_bus = DCBus(C_dc=235e-6, u_dc=sqrt(2) * nom.U)
grid_sys = grid_model.GridConverterSystem(
    grid_model.DiodeBridge(),
    grid_model.LFilter(L_f=1e-3),
    ThreePhaseSource(w_g=base.w, e_g=base.u),
    dc_bus=dc_bus,
)

par = drive_model.InductionMachineInvGammaPars(
    n_p=2, R_s=3.7, R_R=2.1, L_sgm=0.021, L_M=0.224
)
machine = drive_model.InductionMachine(par)
k = 1.1 * nom.tau / base.w_M**2  # Quadratic load torque profile
mechanics = drive_model.MechanicalSystem(J=0.015, B_L=lambda w_M: k * abs(w_M))
converter = drive_model.VoltageSourceConverter(
    modulator=drive_model.CarrierComparison()
)
drive_sys = drive_model.Drive(machine, mechanics, converter, dc_bus=dc_bus)

mdl = CompositeModel({"grid": grid_sys, "drive": drive_sys})

# %%
# Configure the control system as open-loop V/Hz control.

est_par = control.InductionMachineInvGammaPars(n_p=2, R_s=0, R_R=0, L_sgm=0, L_M=inf)
cfg = control.ObserverBasedVHzControllerCfg(
    psi_s_nom=base.psi, i_s_max=inf, alpha_f=0, alpha_tau=0, alpha_psi=0
)
vhz_ctrl = control.ObserverBasedVHzController(est_par, cfg)
ctrl = control.VHzControlSystem(vhz_ctrl, slew_rate=2 * pi * 60)

# %%
# Set the speed reference and the external load torque.

ctrl.set_speed_ref(lambda t: (t > 0.2) * base.w_M)
mechanics.set_external_load_torque(lambda t: (t > 1) * 0.2 * nom.tau)

# %%
# Create the simulation object, with the control system of the drive by the model
# name, and simulate. Plot the drive results in per-unit values.

sim = Simulation(mdl, {"drive": ctrl})
res = sim.simulate(t_stop=1.4)
res_drive = drive_model.SimulationResults(res.mdl.drive, res.ctrl.drive)
# sphinx_gallery_thumbnail_number = 2
drive_utils.plot(res_drive, base)
drive_utils.plot_stator_waveforms(res_drive, base, t_lims=(1.1, 1.125))

# %%
# Plot the grid-side waveforms: the phase-a voltages of the grid and the diode bridge,
# the DC-bus voltage, the phase-a current, and the DC currents of the diode bridge and
# the inverter. The diode bridge conducts in pulses, as the DC-bus voltage is close to
# the peak of the line-to-line grid voltage.

t, grid_ts = res.mdl.t, res.mdl.grid
fig, (ax1, ax2) = plt.subplots(2, 1, sharex=True)
ax1.plot(t, complex2abc(grid_ts.ac_source.e_g_ab)[0] / base.u, label=r"$e_\mathrm{ga}$")
ax1.plot(t, complex2abc(grid_ts.converter.u_c_ab)[0] / base.u, label=r"$u_\mathrm{ca}$")
ax1.plot(t, grid_ts.dc_bus.u_dc / base.u, label=r"$u_\mathrm{dc}$")
ax1.set_ylabel("Voltage (p.u.)")
ax1.legend(loc="lower right")
ax2.plot(t, complex2abc(grid_ts.ac_filter.i_g_ab)[0] / base.i, label=r"$i_\mathrm{ga}$")
ax2.plot(t, -grid_ts.converter.i_dc_int / base.i, label=r"$i_\mathrm{r}$")
ax2.plot(t, res.mdl.drive.converter.i_dc_int / base.i, label=r"$i_\mathrm{i}$")
ax2.set_ylabel("Current (p.u.)")
ax2.set_xlabel("Time (s)")
ax2.set_xlim(1.1, 1.125)
ax2.legend(loc="lower right")
plt.show()

# %%
# .. note::
#    The DC link of this particular example is unstable at 1-p.u. speed at the rated
#    load torque, since the inverter looks like a negative resistance to the DC link.
#    After the speed has settled, an oscillation at about 150 Hz, half the frequency of
#    the six-pulse ripple, grows in the DC-bus voltage. It is seen above as the unequal
#    current pulses of the diode bridge. The oscillation does not grow without bound,
#    but it settles into a limit cycle of about 77 V peak to peak at about 1.5 s. With
#    twice the DC-bus capacitance, the oscillation does not occur, and only the
#    six-pulse ripple remains. For analysis, see e.g., [#Hin2007]_.
#
# .. rubric:: References
#
# .. [#Hin2007] Hinkkanen, Harnefors, Luomi, "Control of induction motor drives equipped
#    with small DC-Link capacitance," Proc. EPE, 2007,
#    https://doi.org/10.1109/EPE.2007.4417763