Environment block for Simscape Power Systems Specialized Technology models
Fundamental Blocks (powerlib)
The powergui block allows you to choose one of these methods to solve your circuit:
Continuous, which uses a variable-step solver from Simulink®
Ideal switching continuous
Discretization of the electrical system for a solution at fixed time steps
The powergui block also opens tools for steady-state and simulation results analysis and for advanced parameter design.
You need the powergui block to simulate any Simulink model containing Simscape™ Power Systems™ Specialized Technology blocks. It stores the equivalent Simulink circuit that represents the state-space equations of the model.
When using one powergui block in a model:
Place the powergui block in the top-level diagram for optimal performance.
Make sure that the block uses the name
The powergui block becomes disabled during model update. To ensure proper model execution, do not restore the library link for the powergui block.
You can use multiple powergui blocks in a system that contains two or more independent electrical circuits that you want to simulate with different powergui solvers. For example, this system simulates the upper electrical circuit in discrete mode and the bottom circuit in continuous mode. The purpose is to compare simulation performance of the two methods.
To do so, put each circuit in two different subsystem, and then add a powergui block inside every subsystem. The figure shows this configuration:
When you use more than one powergui block in a model:
Do not place a powergui block in the top-level diagram.
Place every independent model in a different subsystem.
Place a single powergui block in the top level diagram of every subsystem.
The configuration of the Solver tab depends on the option that you select from the Simulation type list.
default) to perform a continuous solution of the model.
Discrete to perform
a discretization of the model. You specify the sample time in the Sample time parameter.
Phasor to perform
phasor simulation of the model, at the frequency specified by the Phasor frequency parameter.
Select to model the switches and power electronic blocks using
ideal or quasi-ideal switches. For more information, see Using the Ideal Switching Device Method. This parameter
is visible only when the Simulation type parameter
is set to
Continuous. By default,
this option is not selected.
Select to disable the snubber devices of the power electronic and breaker blocks in your model. This parameter is visible only if Use ideal switching devices is selected. By default, this option is not selected.
Select to disable the internal resistance of switches and power electronic devices and to force the value to zero ohms. This parameter is visible only if you select Use ideal switching devices. By default, this option is not selected.
Select to disable the internal forward voltage of power electronic devices and to force the value to zero volts. This parameter is visible only if you select Use ideal switching devices. By default, this option is not selected.
Select to display the differential equations of the model in the Diagnostic Viewer when the simulation starts. This parameter is visible only if you select Use ideal switching devices. For more information, see Using the Ideal Switching Device Method. By default, this option is not selected.
Tustin/Backward Euler (TBE) to
simulate the electrical model using a combination of Tustin and Backward
Tustin to discretize the electrical
model using the Tustin method.
Backward Euler to discretize
the electrical model using the Backward Euler method.
The default and recommended method is the
Euler (TBE) method, as explained in Simulating Discretized Electrical Systems. This parameter
is visible only if you set Simulation Type to
Select to increase simulation speed by enabling the solver to interpolate in discrete models using power electronics. When this option is selected, the solver captures gate transitions of power electronic devices occurring between two sample times, allowing larger sample times (typically 20X) than you use with the standard solvers. For example, simulating a 5 kHz PWM converter with Tustin (no interpolation) or Tustin/Backward Euler normally requires a 1.0 µs sample time (sampling frequency = 200 x PWM frequency) to obtain a good resolution on pulse generation and guarantee accurate results. With interpolation enabled, using a sample time as large as 20 µs executes faster while preserving model accuracy.
When you enable this option:
Use a continuous pulse generator to guarantee the best accuracy on pulse generation (specify sample time = 0 in pulse-generation blocks).
In Simulink Model Configuration Parameters,
select a continuous, variable-step solver (
default settings). The continuous solver is required by the interpolation
solver to compute the gate signals time delays with respect to discrete
sample times. The solver uses these pulse delays to interpolate between
sample times and produce accurate results.
See the power_buck example model to see how interpolation increases accuracy and simulation speed.
The interpolation method computes model outputs at fixed sample times while taking into account switching events that occur between two sample times. The method receives pulses at fixed time steps and computes the time delays of gate signals arriving within each time step. Computing the time delays enables the method to capture the evolution of states at different switching times.
When Use time-stamped gate signals is cleared, the interpolation method computes the time delays of gate signal.
When Use time-stamped gate signals is selected, the block does not compute the time delays of gate signals. You then need to directly provide time-stamped gate signals to the switching devices in your model. See the power_buck example for more information on the concept of time-stamped gate signals in Simscape Power Systems switching devices.
The Use time-stamped gate signals parameter
is visible only when you set Simulation type to
set Solver type to
and select the Interpolate option. By default,
this option is cleared.
Select to increase simulation speed by enabling the solver to
store and reuse matrix computation results. This parameter is visible
only when you set Simulation type to
Discrete, set Solver type to
Tustin, and select the Interpolate option.
By default, this option is not selected.
Specify the buffer size for saving state-space matrix computations.
This parameter is visible only when you set Simulation type to
Discrete, set Solver type to
Tustin, and select the Interpolate and Store
state-space matrices options. The default is value is
Specify the sample time used to discretize the electrical circuit.
This parameter is visible only when the Simulation type parameter
is set to
Set the Sample time parameter
t to a value greater than 0. The powergui block displays
the value of the sample time. The default is value is
Specify the frequency for performing the phasor simulation of
the model. This parameter is visible only when you set Simulation
The default is value is
Open the Steady-State Voltages and Currents Tool dialog box
to display the steady-state voltages and currents of the model. For
more information, see
Open the Initial States Setting Tool dialog box to display and
modify initial capacitor voltages and inductor currents of the model.
For more information, see
Open the Load Flow Tool dialog box to perform load flow and initialize three-phase networks and machines so that the simulation starts in steady state.
The Load Flow tool uses the Newton-Raphson method to provide robust and faster convergence solution compared to the Machine Initialization tool.
The Load Flow tool offers most of the functionality of other
tools available in the power utility industry. For more information,
Open the Machine Initialization Tool dialog box to initialize
three-phase networks containing three-phase machines so that the simulation
starts in steady state. The Machine Initialization tool offers simplified
load flow features but can still initialize machine initial currents
of your models. For more information, see
Open the Impedance vs Frequency Measurement Tool dialog box
to display the impedance versus frequency defined by the Impedance
Measurement blocks. For more information, see
Open the FFT Analysis Tool dialog box to perform Fourier analysis
of signals stored in a structure with time format. For more information,
See Performing Harmonic Analysis Using the FFT Toolfor an example that uses the FFT Analysis tool .
Open a window to generate the state-space model of your system
(if you have Control System Toolbox™ software installed) and open
the Linear System Analyzer interface for time and frequency domain
responses. For more information, see
Open a window to design a hysteresis characteristic for the
saturable core of the Saturable Transformer block and the Three-Phase
Transformer blocks (two- and three-windings). For more information,
Open a window to compute RLC parameters of an overhead transmission
line from conductor characteristics and tower geometry. For more information,
Open the Generate Report Tool dialog box to generate a report
of steady-state variables, initial states, and machine load flow for
a model. For more information, see
create custom Simscape Power Systems Specialized Technology blocks.
The load flow parameters are for model initialization only. They do not have an impact on simulation performance.
When this check box is selected, the Simscape Power Systems warnings do not display during model analysis and simulation. By default, this option is not selected.
Select to enable the command-line echo messages during model analysis. By default, this option is not selected.
Select to use TLC state-space S-functions (
in Accelerator mode and for code generation.
Clear this box if you notice a slowdown in performance when
using Accelerator mode, compared to previous releases. This slowdown
occurs if you have the LCC compiler installed as the default compiler
for building external interface (
mex). By default,
this option is not selected.
blocks is selected, initial state
values defined in blocks are used for the simulation.
steady is selected, force all
initial electrical state values to steady-state values.
zero is selected, force all initial
electrical state values to zero.
The default is
Specify the frequency used by the Load Flow tool to compute
the normalized Ybus network admittance matrix of the model and to
perform the load flow calculations. The default value is
Specify the base power used by the Load Flow tool to compute the normalized Ybus network admittance matrix in pu/Pbase and bus base voltages of the model, at the frequency specified by the Load flow frequency parameter.
To avoid a badly conditioned Ybus matrix, select the base power
value in the range of nominal powers and loads of the model. For a
transmission network with voltages ranging from 120 kV to 765 kV,
a 100 MVA base is usually selected. For a distribution network or
for a small plant consisting of generators, motors, and loads having
a nominal power in the range of hundreds of kilowatts, a 1 MVA base
power is better adapted. The default value is
Defines the tolerance between P and Q when the Load flow tool
stops to iterate. The default value is
Defines the maximum number of iterations the Load flow tool
iterates until the P and Q powers mismatch at each bus is lower than
the PQ tolerance parameter value (in pu/Pbase).
The power mismatch is defined as the difference between the net power
injected into the bus by generators and loads and the power transmitted
on all links leaving that bus. For example, if the base power is 100
MVA and PQ tolerance is set to
the maximum power mismatch at all buses does not exceed 0.1 MW or
0.1 Mvar. The default value is
Determine the voltage units (V, kV) used by the Load Flow tool
to display voltages. The default is
Determine the power units (W, kW, MW) used by the Load Flow
tool to display powers. The default is