diff --git a/examples/grid_following/plot_gfl_10kva.py b/examples/grid_following/plot_gfl_10kva.py
index 1efb68db6..933ca4e09 100644
--- a/examples/grid_following/plot_gfl_10kva.py
+++ b/examples/grid_following/plot_gfl_10kva.py
@@ -14,7 +14,7 @@
 from motulator.common.utils import BaseValues, NominalValues
 from motulator.grid import model
 import motulator.grid.control.grid_following as control
-from motulator.grid.utils import FilterPars, GridPars, plot_grid
+from motulator.grid.utils import FilterPars, GridPars, plot
 # from motulator.grid.utils import plot_voltage_vector
 # from motulator.common.model import CarrierComparison
 # import numpy as np
@@ -38,8 +38,7 @@
 ac_filter = model.ACFilter(filter_par, grid_par)
 
 # AC grid model with constant voltage magnitude and frequency
-grid_model = model.ThreePhaseVoltageSource(
-    w_g=grid_par.w_gN, abs_e_g=grid_par.u_gN)
+grid_model = model.ThreePhaseVoltageSource(w_g=base.w, abs_e_g=base.u)
 
 # Inverter with constant DC voltage
 converter = VoltageSourceConverter(u_dc=650)
@@ -54,8 +53,7 @@
 # Configure the control system.
 
 # Control configuration parameters
-cfg = control.GFLControlCfg(
-    grid_par=grid_par, filter_par=filter_par, max_i=1.5*base.i)
+cfg = control.GFLControlCfg(grid_par, filter_par, max_i=1.5*base.i)
 
 # Create the control system
 ctrl = control.GFLControl(cfg)
@@ -68,8 +66,8 @@
 ctrl.ref.q_g = lambda t: (t > .04)*4e3
 
 # Uncomment lines below to simulate a unbalanced fault (add negative sequence)
-# mdl.grid_model.par.abs_e_g = 0.75*base.u
-# mdl.grid_model.par.abs_e_g_neg = 0.25*base.u
+# mdl.grid_model.par.abs_e_g = .75*base.u
+# mdl.grid_model.par.abs_e_g_neg = .25*base.u
 # mdl.grid_model.par.phi_neg = -np.pi/3
 
 # %%
@@ -86,4 +84,4 @@
 
 # Uncomment line below to plot locus of the grid voltage space vector
 # plot_voltage_vector(sim, base)
-plot_grid(sim, base, plot_pcc_voltage=True)
+plot(sim, base, plot_pcc_voltage=False)
diff --git a/examples/grid_following/plot_gfl_dc_bus_10kva.py b/examples/grid_following/plot_gfl_dc_bus_10kva.py
index afab30d8a..05b3380e6 100644
--- a/examples/grid_following/plot_gfl_dc_bus_10kva.py
+++ b/examples/grid_following/plot_gfl_dc_bus_10kva.py
@@ -15,7 +15,7 @@
 from motulator.grid import model
 import motulator.grid.control.grid_following as control
 from motulator.grid.control import DCBusVoltageController
-from motulator.grid.utils import FilterPars, GridPars, plot_grid
+from motulator.grid.utils import FilterPars, GridPars, plot
 
 # %%
 # Compute base values based on the nominal values.
@@ -35,12 +35,8 @@
 # Create AC filter with given parameters
 ac_filter = model.ACFilter(filter_par, grid_par)
 
-# AC-voltage magnitude (to simulate voltage dips or short-circuits)
-abs_e_g_var = lambda t: base.u
-
 # AC grid model with constant voltage magnitude and frequency
-grid_model = model.ThreePhaseVoltageSource(
-    w_g=grid_par.w_gN, abs_e_g=abs_e_g_var)
+grid_model = model.ThreePhaseVoltageSource(w_g=base.w, abs_e_g=base.u)
 
 # Inverter model with DC-bus dynamics included
 converter = VoltageSourceConverter(u_dc=600, C_dc=1e-3)
@@ -51,14 +47,8 @@
 # %%
 # Configure the control system.
 
-# Control parameters
-cfg = control.GFLControlCfg(
-    grid_par=grid_par,
-    C_dc=1e-3,
-    filter_par=filter_par,
-    max_i=1.5*base.i,
-)
 # Create the control system
+cfg = control.GFLControlCfg(grid_par, filter_par, max_i=1.5*base.i, C_dc=1e-3)
 ctrl = control.GFLControl(cfg)
 
 # Add the DC-bus voltage controller to the control system
@@ -86,4 +76,4 @@
 # By default results are plotted in per-unit values. By omitting the argument
 # `base` you can plot the results in SI units.
 
-plot_grid(sim=sim, base=base, plot_pcc_voltage=True)
+plot(sim, base)
diff --git a/examples/grid_following/plot_gfl_lcl_10kva.py b/examples/grid_following/plot_gfl_lcl_10kva.py
index f354da5eb..726bc9d0f 100644
--- a/examples/grid_following/plot_gfl_lcl_10kva.py
+++ b/examples/grid_following/plot_gfl_lcl_10kva.py
@@ -14,7 +14,7 @@
 from motulator.common.utils import BaseValues, NominalValues
 from motulator.grid import model
 import motulator.grid.control.grid_following as control
-from motulator.grid.utils import FilterPars, GridPars, plot_grid
+from motulator.grid.utils import FilterPars, GridPars, plot
 
 # %%
 # Compute base values based on the nominal values.
@@ -32,12 +32,8 @@
 # DC-bus parameters
 ac_filter = model.ACFilter(filter_par, grid_par)
 
-# AC-voltage magnitude (to simulate voltage dips or short-circuits)
-abs_e_g_var = lambda t: grid_par.u_gN
-
 # AC grid model with constant voltage magnitude and frequency
-grid_model = model.ThreePhaseVoltageSource(
-    w_g=grid_par.w_gN, abs_e_g=abs_e_g_var)
+grid_model = model.ThreePhaseVoltageSource(w_g=base.w, abs_e_g=base.u)
 
 # Inverter model with constant DC voltage
 converter = VoltageSourceConverter(u_dc=650)
@@ -45,15 +41,11 @@
 # Create system model
 mdl = model.GridConverterSystem(converter, ac_filter, grid_model)
 
-# Uncomment line below to enable the PWM model
-#mdl.pwm = CarrierComparison()
-
 # %%
 # Configure the control system.
 
 # Control parameters
-cfg = control.GFLControlCfg(
-    grid_par=grid_par, filter_par=filter_par, max_i=1.5*base.i)
+cfg = control.GFLControlCfg(grid_par, filter_par, max_i=1.5*base.i)
 
 # Create the control system
 ctrl = control.GFLControl(cfg)
@@ -74,7 +66,4 @@
 # %%
 # Plot the results.
 
-# By default results are plotted in per-unit values. By omitting the argument
-# `base` you can plot the results in SI units.
-
-plot_grid(sim, base=base, plot_pcc_voltage=True)
+plot(sim, base)
diff --git a/examples/grid_forming/plot_gfm_obs_13kva.py b/examples/grid_forming/plot_gfm_obs_13kva.py
index 9c2742739..c6aa9c488 100644
--- a/examples/grid_forming/plot_gfm_obs_13kva.py
+++ b/examples/grid_forming/plot_gfm_obs_13kva.py
@@ -14,7 +14,7 @@
 from motulator.common.utils import BaseValues, NominalValues
 from motulator.grid import model
 import motulator.grid.control.grid_forming as control
-from motulator.grid.utils import FilterPars, GridPars, plot_grid
+from motulator.grid.utils import FilterPars, GridPars, plot
 # from motulator.common.model import CarrierComparison
 
 # %%
@@ -38,8 +38,7 @@
 ac_filter = model.ACFilter(filter_par, grid_par)
 
 # Grid voltage source with constant frequency and voltage magnitude
-grid_model = model.ThreePhaseVoltageSource(
-    w_g=grid_par.w_gN, abs_e_g=grid_par.u_gN)
+grid_model = model.ThreePhaseVoltageSource(w_g=base.w, abs_e_g=base.u)
 
 # Inverter with constant DC voltage
 converter = VoltageSourceConverter(u_dc=650)
@@ -47,9 +46,6 @@
 # Create system model
 mdl = model.GridConverterSystem(converter, ac_filter, grid_model)
 
-# Uncomment the lines below to enable the PWM model
-# mdl.pwm = CarrierComparison()
-
 # %%
 # Configure the control system.
 
@@ -58,11 +54,7 @@
 
 # Set the configuration parameters
 cfg = control.ObserverBasedGFMControlCfg(
-    grid_par=grid_par_est,
-    filter_par=filter_par,
-    T_s=100e-6,
-    max_i=1.3*base.i,
-    R_a=.2*base.Z)
+    grid_par_est, filter_par, max_i=1.3*base.i, T_s=100e-6, R_a=.2*base.Z)
 
 # Create the control system
 ctrl = control.ObserverBasedGFMControl(cfg)
@@ -71,19 +63,18 @@
 # Set the references for converter output voltage magnitude and active power.
 
 # Converter output voltage magnitude reference
-ctrl.ref.v_c = lambda t: grid_par.u_gN
+ctrl.ref.v_c = lambda t: base.u
 
 # Active power reference
-ctrl.ref.p_g = lambda t: ((t > .2)*(4.15e3) + (t > .5)*(4.15e3) + (t > .8)*
-                          (4.2e3) - (t > 1.2)*(12.5e3))
+ctrl.ref.p_g = lambda t: ((t > .2)/3 + (t > .5)/3 + (t > .8)/3 -
+                          (t > 1.2))*nom.P
 
 # Uncomment line below to simulate operation in rectifier mode
-# ctrl.ref.p_g = lambda t: ((t > .2) - (t > .7)*2 + (t > 1.2))*12.5e3
+# ctrl.ref.p_g = lambda t: ((t > .2) - (t > .7)*2 + (t > 1.2))*nom.P
 
 # Uncomment lines below to simulate a grid voltage sag with constant ref.p_g
-# mdl.grid_model.par.e_g_abs = lambda t: (
-#    1 - (t > .2)*(0.8) + (t > 1)*(0.8))*grid_par.u_gN
-# ctrl.ref.p_g = lambda t: 12.5e3
+# mdl.grid_model.par.abs_e_g = lambda t: (1 - (t > .2)*.8 + (t > 1)*.8)*base.u
+# ctrl.ref.p_g = lambda t: nom.P
 
 # %%
 # Create the simulation object and simulate it.
@@ -94,7 +85,4 @@
 # %%
 # Plot the results.
 
-# By default results are plotted in per-unit values. By omitting the argument
-# `base` you can plot the results in SI units.
-
-plot_grid(sim=sim, base=base, plot_pcc_voltage=False)
+plot(sim, base)
diff --git a/examples/grid_forming/plot_gfm_rfpsc_13kva.py b/examples/grid_forming/plot_gfm_rfpsc_13kva.py
index 4751f1783..d42205cf1 100644
--- a/examples/grid_forming/plot_gfm_rfpsc_13kva.py
+++ b/examples/grid_forming/plot_gfm_rfpsc_13kva.py
@@ -12,7 +12,7 @@
 from motulator.common.utils import BaseValues, NominalValues
 from motulator.grid import model
 import motulator.grid.control.grid_forming as control
-from motulator.grid.utils import FilterPars, GridPars, plot_grid
+from motulator.grid.utils import FilterPars, GridPars, plot
 
 # %%
 # Compute base values based on the nominal values.
@@ -35,8 +35,7 @@
 ac_filter = model.ACFilter(filter_par, grid_par)
 
 # Grid voltage source with constant frequency and voltage magnitude
-grid_model = model.ThreePhaseVoltageSource(
-    w_g=grid_par.w_gN, abs_e_g=grid_par.u_gN)
+grid_model = model.ThreePhaseVoltageSource(w_g=base.w, abs_e_g=base.u)
 
 # Inverter with constant DC voltage
 converter = VoltageSourceConverter(u_dc=650)
@@ -49,11 +48,7 @@
 
 # Control configuration parameters
 cfg = control.RFPSCControlCfg(
-    grid_par=grid_par,
-    filter_par=filter_par,
-    T_s=100e-6,
-    max_i=1.3*base.i,
-    R_a=.2*base.Z)
+    grid_par, filter_par, max_i=1.3*base.i, T_s=100e-6, R_a=.2*base.Z)
 
 # Create the control system
 ctrl = control.RFPSCControl(cfg)
@@ -62,10 +57,10 @@
 # Set the references for converter output voltage magnitude and active power.
 
 # Converter output voltage magnitude reference
-ctrl.ref.v = lambda t: grid_par.u_gN
+ctrl.ref.v_c = lambda t: base.u
 
 # Active power reference
-ctrl.ref.p_g = lambda t: ((t > .2)*(1/3) + (t > .5)*(1/3) + (t > .8)*(1/3) -
+ctrl.ref.p_g = lambda t: ((t > .2)/3 + (t > .5)/3 + (t > .8)/3 -
                           (t > 1.2))*nom.P
 
 # %%
@@ -77,7 +72,4 @@
 # %%
 # Plot the results.
 
-# By default results are plotted in per-unit values. By omitting the argument
-# `base` you can plot the results in SI units.
-
-plot_grid(sim, base=base, plot_pcc_voltage=True)
+plot(sim, base)
diff --git a/motulator/common/control/_control.py b/motulator/common/control/_control.py
index 227d2910c..79e001036 100644
--- a/motulator/common/control/_control.py
+++ b/motulator/common/control/_control.py
@@ -294,10 +294,8 @@ class ComplexPIController:
     2DOF synchronous-frame complex-vector PI controller.
 
     This implements a discrete-time 2DOF synchronous-frame complex-vector PI
-    controller, based on a disturbance observer structure. The complex-vector
-    gain selection is based on [#Bri2000]_. The addition of the feedforward
-    signal is based on [#Har2009]_. The continuous-time counterpart of
-    the controller is::
+    controller [#Bri2000]_. The continuous-time counterpart of the controller 
+    is::
 
         u = k_t*ref_i - k_p*i + (k_i + 1j*w*k_t)/s*(ref_i - i) + u_ff
 
@@ -330,11 +328,9 @@ class ComplexPIController:
     """
 
     def __init__(self, k_p, k_i, k_t=None):
-        # Gains
         self.k_p = k_p
         self.k_t = k_t if k_t is not None else k_p
         self.alpha_i = k_i/self.k_t  # Inverse of the integration time T_i
-        # States
         self.v, self.u_i = 0, 0
 
     def output(self, ref_i, i, u_ff=0):
diff --git a/motulator/grid/control/grid_forming/_observer_gfm.py b/motulator/grid/control/grid_forming/_observer_gfm.py
index cbb0678c1..1c737b380 100644
--- a/motulator/grid/control/grid_forming/_observer_gfm.py
+++ b/motulator/grid/control/grid_forming/_observer_gfm.py
@@ -1,4 +1,4 @@
-"""Disturbance observer-based grid-forming control for grid converters."""
+"""Disturbance-observer-based grid-forming control for grid converters."""
 
 # %%
 from dataclasses import dataclass
@@ -14,7 +14,7 @@
 @dataclass
 class ObserverBasedGFMControlCfg:
     """
-    Observer GFM control configuration.
+    Disturbance-observer-based grid-forming control configuration.
 
     Parameters
     ----------
@@ -27,15 +27,15 @@ class ObserverBasedGFMControlCfg:
     R_a : float
         Active resistance (Ω).
     T_s : float, optional
-        Sampling period of the controller (s). Default is 1/(16e3).
+        Sampling period of the controller (s). Default is 100e-6.
     k_v : float, optional
-        Voltage gain. Default is 1.
+        Voltage gain. The default is 1.
     alpha_c : float, optional
         Current control bandwidth (rad/s). The default is 2*pi*400.
     alpha_o : float, optional
         Observer gain (rad/s). The default is 2*pi*50.
     C_dc : float, optional
-        DC-bus capacitance (F). Default is None.
+        DC-bus capacitance (F). The default is None.
 
     """
 
@@ -59,26 +59,27 @@ def __post_init__(self):
 # %%
 class ObserverBasedGFMControl(GridConverterControlSystem):
     """
-    Disturbance observer-based grid-forming control for grid converters.
+    Disturbance-observer-based grid-forming control for grid converters.
     
-    This implements the disturbance observer-based control method described in
-    [#Nur2024]_. More specifically, the grid-forming mode using RFPSC-type
-    gains is implemented, with transparent current control.
+    This implements the RFPSC-type grid-forming mode of the control method 
+    described in [#Nur2024]_. Transparent current control is also implemented.
 
     Parameters
     ----------
     cfg : ObserverBasedGFMControlCfg
-        Model and controller configuration parameters.
-
-    Attributes
-    ----------
-    observer : DisturbanceObserver
-        Disturbance observer.
+        Controller configuration parameters.
+
+    Notes
+    -----
+    In this implementation, the control system operates in synchronous 
+    coordinates rotating at the nominal grid angular frequency, which is worth
+    noticing when plotting the results. For other implementation options, see
+    [#Nur2024]_. 
     
     References
     ----------
     .. [#Nur2024] Nurminen, Mourouvin, Hinkkanen, Kukkola, "Multifunctional
-        Grid-Forming Converter Control Based on a Disturbance Observer, "IEEE
+        grid-forming converter control based on a disturbance observer, "IEEE
         Trans. Power Electron., 2024, https://doi.org/10.1109/TPEL.2024.3433503
 
     """
@@ -109,20 +110,17 @@ def output(self, fbk):
 
         # Get the reference signals
         ref = super().output(fbk)
-        if self.dc_bus_volt_ctrl:
-            ref.u_dc = self.ref.u_dc(ref.t)
         ref = super().get_power_reference(fbk, ref)
-        # Converter voltage magnitude reference
         ref.v_c = self.ref.v_c(ref.t) if callable(
             self.ref.v_c) else self.ref.v_c
 
-        # Calculation of complex gains (grid-forming)
+        # Complex gains for grid-forming mode
         abs_k_p = cfg.R_a/(1.5*ref.v_c)
         abs_v_c = np.abs(fbk.v_c)
         k_p = abs_k_p*fbk.v_c/abs_v_c if abs_v_c > 0 else 0
         k_v = (1 - cfg.k_v*1j)*fbk.v_c/abs_v_c if abs_v_c > 0 else 0
 
-        # Calculation of feedback correction term (grid-forming)
+        # Feedback correction term for grid-forming mode
         fbk.e_c = k_p*(ref.p_g - fbk.p_g) + k_v*(ref.v_c - abs_v_c)
 
         # Current limitation
@@ -131,21 +129,13 @@ def output(self, fbk):
             ref.i_c_lim = ref.i_c/np.abs(ref.i_c)*cfg.max_i
             fbk.e_c = cfg.k_c*(ref.i_c_lim - fbk.i_c)
 
-        # Calculation of voltage reference
+        # Voltage reference
         ref.u_c = fbk.e_c + fbk.v_c + cfg.R*fbk.i_c
         ref.u_cs = np.exp(1j*fbk.theta_c)*ref.u_c
 
         # Duty ratios for PWM
         ref.d_abc = self.pwm(ref.T_s, ref.u_cs, fbk.u_dc, par.w_gN)
 
-        # Apply a coordinate transformation to values that are plotted in
-        # synchronous coordinates, as by default the coordinate system of the
-        # observer is not fixed to the converter voltage vector.
-        T = np.conj(fbk.v_c)/np.abs(fbk.v_c) if np.abs(fbk.v_c) > 0 else 0
-        ref.u_c = T*ref.u_c
-        fbk.i_c = T*fbk.i_c
-        ref.i_c = T*ref.i_c
-
         return ref
 
     def update(self, fbk, ref):
@@ -158,14 +148,14 @@ class DisturbanceObserver:
     """
     Disturbance observer.
     
-    This implements a disturbance observer, which estimates the converter 
-    output voltage. The observer could be implemented in any coordinates. Here
-    coordinates rotating at the nominal grid angular frequency are used.
+    This implements a disturbance observer, which estimates the quasi-static
+    converter output voltage. Coordinates rotating at the nominal grid angular 
+    frequency are used.
 
     Parameters
     ----------
     w_g : float
-        Estimate of grid angular frequency (rad/s).
+        Nominal grid angular frequency (rad/s).
     L : float
         Estimate of total inductance (H) between converter and grid.
     alpha_o : float
@@ -193,11 +183,10 @@ def output(self, fbk):
         # Active and reactive power
         fbk.p_g = 1.5*np.real(fbk.v_c*np.conj(fbk.i_c))
         fbk.q_g = 1.5*np.imag(fbk.u_g*np.conj(fbk.i_c))
-
         return fbk
 
     def update(self, fbk, ref):
-        """Update the observer integral states."""
+        """Update the observer states."""
         self.v_cp += ref.T_s*(self.k_o + 1j*self.w_c)*fbk.e_c + 1j*(
             self.w_g - self.w_c)*self.v_cp
         self.theta_c += ref.T_s*self.w_c
diff --git a/motulator/grid/control/grid_forming/_power_synchronization.py b/motulator/grid/control/grid_forming/_power_synchronization.py
index 23029b5e8..e2e0a733d 100644
--- a/motulator/grid/control/grid_forming/_power_synchronization.py
+++ b/motulator/grid/control/grid_forming/_power_synchronization.py
@@ -24,8 +24,8 @@ class RFPSCControlCfg:
         Filter model parameters.
     max_i : float
         Maximum current modulus (A).
-    R_a : float, optional
-        Damping resistance (Ω). Default is 4.6.
+    R_a : float
+        Damping resistance (Ω).
     T_s : float, optional
         Sampling period of the controller (s). The default is 100e-6.
     w_b : float, optional
@@ -96,20 +96,21 @@ def output(self, fbk):
         # Get the reference signals
         ref = super().output(fbk)
         ref = super().get_power_reference(fbk, ref)
-        ref.v = self.ref.v(ref.t) if callable(self.ref.v) else self.ref.v
+        ref.v_c = self.ref.v_c(ref.t) if callable(
+            self.ref.v_c) else self.ref.v_c
 
         # Calculation of power droop
         fbk.w_c = par.w_gN + cfg.k_p_psc*(ref.p_g - fbk.p_c)
 
         # Optionally, use of reference feedforward for d-axis current
-        ref.i_c = ref.p_g/(1.5*ref.v) + 1j*fbk.i_c_flt.imag
+        ref.i_c = ref.p_g/(1.5*ref.v_c) + 1j*fbk.i_c_flt.imag
         # ref.i_c = fbk.i_c_flt  # Conventional PSC
 
         # Limit the current reference
         ref.i_c = self.current_limiter(ref.i_c)
 
         # Calculation of converter voltage output reference
-        ref.u_c = ref.v + cfg.R_a*(ref.i_c - fbk.i_c)
+        ref.u_c = ref.v_c + cfg.R_a*(ref.i_c - fbk.i_c)
         ref.u_cs = np.exp(1j*fbk.theta_c)*ref.u_c
 
         # Duty ratios for PWM
diff --git a/motulator/grid/utils/__init__.py b/motulator/grid/utils/__init__.py
index f3692917c..b20620dd6 100644
--- a/motulator/grid/utils/__init__.py
+++ b/motulator/grid/utils/__init__.py
@@ -1,7 +1,7 @@
 """This module contains utility functions for grid converters."""
 
 from motulator.grid.utils._plots import (
-    plot_grid,
+    plot,
     plot_voltage_vector,
 )
 from motulator.grid.utils._utils import FilterPars, GridPars
@@ -9,6 +9,6 @@
 __all__ = [
     "FilterPars",
     "GridPars",
-    "plot_grid",
+    "plot",
     "plot_voltage_vector",
 ]
diff --git a/motulator/grid/utils/_plots.py b/motulator/grid/utils/_plots.py
index 7f187bad6..8d3ad6fce 100644
--- a/motulator/grid/utils/_plots.py
+++ b/motulator/grid/utils/_plots.py
@@ -8,6 +8,7 @@
 from cycler import cycler
 
 from motulator.common.utils import complex2abc
+#import motulator.grid.control.grid_forming as control  # To check instance type
 
 # Plotting parameters
 plt.rcParams["axes.prop_cycle"] = cycler(color="brgcmyk")
@@ -17,8 +18,7 @@
 
 
 # %%
-def plot_grid(
-        sim, base=None, plot_pcc_voltage=False, plot_w=False, t_span=None):
+def plot(sim, base=None, plot_pcc_voltage=True, plot_w=False, t_span=None):
     """
     Plot example figures of grid converter simulations.
 
@@ -30,9 +30,9 @@ def plot_grid(
         Base values for scaling the waveforms. If not given, plots the figures 
         in SI units.
     plot_pcc_voltage : bool, optional
-        If True, plot the phase voltage waveforms at the point of common 
-        coupling (PCC). Otherwise, plot the grid voltage waveforms. The default 
-        is False.        
+        If True, the phase voltage waveforms are plotted at the point of common 
+        coupling (PCC). Otherwise, the grid voltage waveforms are plotted. The 
+        default is True.        
     plot_w : bool, optional
         If True, plot the grid frequency. Otherwise, plot the phase angle. The 
         default is False.
@@ -58,7 +58,6 @@ def plot_grid(
         pu_vals = True
 
     # Three-phase quantities
-    #i_c_abc = complex2abc(mdl.converter.data.i_cs).T
     i_g_abc = complex2abc(mdl.ac_filter.data.i_gs).T
     e_g_abc = complex2abc(mdl.grid_model.data.e_gs).T
     u_g_abc = complex2abc(mdl.ac_filter.data.u_gs).T
@@ -68,8 +67,16 @@ def plot_grid(
         np.real(mdl.ac_filter.data.e_gs*np.conj(mdl.ac_filter.data.i_gs)))
     q_g = 1.5*np.asarray(
         np.imag(mdl.ac_filter.data.e_gs*np.conj(mdl.ac_filter.data.i_gs)))
-    p_g_ref = np.asarray(ctrl.ref.p_g)
-    q_g_ref = np.asarray(ctrl.ref.q_g)
+
+    # Coordinate transformation in the case of observer-based GFM control
+    if hasattr(sim.ctrl, "observer"):
+        # Convert quantities to converter-output-voltage coordinates
+        T = np.where(
+            np.abs(ctrl.fbk.v_c) > 0,
+            np.conj(ctrl.fbk.v_c)/np.abs(ctrl.fbk.v_c), 1)
+        ctrl.ref.u_c = T*ctrl.ref.u_c
+        ctrl.fbk.i_c = T*ctrl.fbk.i_c
+        ctrl.ref.i_c = T*ctrl.ref.i_c
 
     # %%
     fig, (ax1, ax2, ax3) = plt.subplots(3, 1, figsize=(10, 7))
@@ -95,7 +102,7 @@ def plot_grid(
         # Subplot 1: DC-bus voltage
         ax1.plot(
             mdl.converter.data.t,
-            mdl.converter.data.u_dc.T/base.u,
+            mdl.converter.data.u_dc/base.u,
             label=r"$u_\mathrm{dc}$")
         ax1.plot(
             ctrl.t,
@@ -174,12 +181,14 @@ def plot_grid(
     ax1.plot(mdl.ac_filter.data.t, p_g/base.p, label=r"$p_\mathrm{g}$")
     ax1.plot(mdl.ac_filter.data.t, q_g/base.p, label=r"$q_\mathrm{g}$")
     ax1.plot(
-        ctrl.t, (p_g_ref/base.p),
+        ctrl.t,
+        ctrl.ref.p_g/base.p,
         "--",
         label=r"$p_\mathrm{g,ref}$",
         ds="steps-post")
     ax1.plot(
-        ctrl.t, (q_g_ref/base.p),
+        ctrl.t,
+        ctrl.ref.q_g/base.p,
         "--",
         label=r"$q_\mathrm{g,ref}$",
         ds="steps-post")