PLECS
Encyclopedia
PLECS is a Simulink
toolbox for system-level simulations of electrical circuits developed by Plexim.
It is especially designed for power electronics
but can be used for any electrical network
.
is ideally suited for the simulation of controls. Therefore, Simulink
is also a convenient tool for the design of closed loop
controlled electrical systems. PLECS enhances Simulink
with the capability to simulate electrical circuits directly. The user can simply enter a circuit as a schematic
of electrical components. At Simulink
block level the circuit is represented as a subsystem, so the user can build controls and other non-electrical elements around it and take full advantage of the Simulink
environment and its toolboxes.
The concept of integration into Simulink
has the advantage that only the part of the system in which electrical units are of interest needs to be modeled as an electrical circuit. The simulation of all non-electrical parts such as controls and mechanics should be done in Simulink
.
MATLAB
can be employed to compute circuit parameters and to post process and visualize the simulation results.
system
s directly within the PLECS package. The standalone version uses GNU Octave
as its numerical engine in place of MATLAB.
model switches as highly nonlinear elements. Due to steep voltage and current transient
s, the simulation becomes slow when switches are toggled. In the most simple case a switch is modeled as a variable resistance that changes between a very small and a very large value. In other cases, it is represented by a sophisticated semiconductor model.
When simulating complex power electronic systems
, however, the processes during switching are of little interest. Here, it is more appropriate to use ideal switches that toggle instantaneously between a closed and an open circuit. This approach, which is implemented in PLECS, has two major advantages: Firstly, it yields systems that are piecewise-linear across switching instants, (thus resolving the otherwise difficult problem of simulating the non-linear discontinuity that occurs in the equivalent-circuit at the switching instant). Secondly, to handle discontinuities at the switching instants, only two integration steps are required (one for before the instant, and one after). Both of these advantages speed up the simulation considerably.
Simulink
Simulink, developed by MathWorks, is a commercial tool for modeling, simulating and analyzing multidomain dynamic systems. Its primary interface is a graphical block diagramming tool and a customizable set of block libraries. It offers tight integration with the rest of the MATLAB environment and...
toolbox for system-level simulations of electrical circuits developed by Plexim.
It is especially designed for power electronics
Power electronics
Power electronics is the application of solid-state electronics for the control and conversion of electric power.-Introduction:Power electronic converters can be found wherever there is a need to modify a form of electrical energy...
but can be used for any electrical network
Electrical network
An electrical network is an interconnection of electrical elements such as resistors, inductors, capacitors, transmission lines, voltage sources, current sources and switches. An electrical circuit is a special type of network, one that has a closed loop giving a return path for the current...
.
Integration with MATLAB/Simulink or Standalone
The program SimulinkSimulink
Simulink, developed by MathWorks, is a commercial tool for modeling, simulating and analyzing multidomain dynamic systems. Its primary interface is a graphical block diagramming tool and a customizable set of block libraries. It offers tight integration with the rest of the MATLAB environment and...
is ideally suited for the simulation of controls. Therefore, Simulink
Simulink
Simulink, developed by MathWorks, is a commercial tool for modeling, simulating and analyzing multidomain dynamic systems. Its primary interface is a graphical block diagramming tool and a customizable set of block libraries. It offers tight integration with the rest of the MATLAB environment and...
is also a convenient tool for the design of closed loop
Closed loop
Closed loop may refer to:* A feedback loop, often found in:** Control theory#Closed-loop transfer function, where a closed-loop controller may be used** Electronic feedback loops in electronic circuits** PID controller, a commonly used closed-loop controller...
controlled electrical systems. PLECS enhances Simulink
Simulink
Simulink, developed by MathWorks, is a commercial tool for modeling, simulating and analyzing multidomain dynamic systems. Its primary interface is a graphical block diagramming tool and a customizable set of block libraries. It offers tight integration with the rest of the MATLAB environment and...
with the capability to simulate electrical circuits directly. The user can simply enter a circuit as a schematic
Circuit diagram
A circuit diagram is a simplified conventional graphical representation of an electrical circuit...
of electrical components. At Simulink
Simulink
Simulink, developed by MathWorks, is a commercial tool for modeling, simulating and analyzing multidomain dynamic systems. Its primary interface is a graphical block diagramming tool and a customizable set of block libraries. It offers tight integration with the rest of the MATLAB environment and...
block level the circuit is represented as a subsystem, so the user can build controls and other non-electrical elements around it and take full advantage of the Simulink
Simulink
Simulink, developed by MathWorks, is a commercial tool for modeling, simulating and analyzing multidomain dynamic systems. Its primary interface is a graphical block diagramming tool and a customizable set of block libraries. It offers tight integration with the rest of the MATLAB environment and...
environment and its toolboxes.
The concept of integration into Simulink
Simulink
Simulink, developed by MathWorks, is a commercial tool for modeling, simulating and analyzing multidomain dynamic systems. Its primary interface is a graphical block diagramming tool and a customizable set of block libraries. It offers tight integration with the rest of the MATLAB environment and...
has the advantage that only the part of the system in which electrical units are of interest needs to be modeled as an electrical circuit. The simulation of all non-electrical parts such as controls and mechanics should be done in Simulink
Simulink
Simulink, developed by MathWorks, is a commercial tool for modeling, simulating and analyzing multidomain dynamic systems. Its primary interface is a graphical block diagramming tool and a customizable set of block libraries. It offers tight integration with the rest of the MATLAB environment and...
.
MATLAB
MATLAB
MATLAB is a numerical computing environment and fourth-generation programming language. Developed by MathWorks, MATLAB allows matrix manipulations, plotting of functions and data, implementation of algorithms, creation of user interfaces, and interfacing with programs written in other languages,...
can be employed to compute circuit parameters and to post process and visualize the simulation results.
Standalone version
There is also a standalone version of PLECS that allows simulation of electrical circuits and controlControl theory
Control theory is an interdisciplinary branch of engineering and mathematics that deals with the behavior of dynamical systems. The desired output of a system is called the reference...
system
Control system
A control system is a device, or set of devices to manage, command, direct or regulate the behavior of other devices or system.There are two common classes of control systems, with many variations and combinations: logic or sequential controls, and feedback or linear controls...
s directly within the PLECS package. The standalone version uses GNU Octave
GNU Octave
GNU Octave is a high-level language, primarily intended for numerical computations. It provides a convenient command-line interface for solving linear and nonlinear problems numerically, and for performing other numerical experiments using a language that is mostly compatible with MATLAB...
as its numerical engine in place of MATLAB.
Semiconductors modeled as ideal switches
Most circuit simulation programsElectronic circuit simulation
Electronic circuit simulation uses mathematical models to replicate the behavior of an actual electronic device or circuit.Simulation software allows for modeling of circuit operation and is an invaluable analysis tool...
model switches as highly nonlinear elements. Due to steep voltage and current transient
Transient (oscillation)
A transient event is a short-lived burst of energy in a system caused by a sudden change of state.The source of the transient energy may be an internal event or a nearby event...
s, the simulation becomes slow when switches are toggled. In the most simple case a switch is modeled as a variable resistance that changes between a very small and a very large value. In other cases, it is represented by a sophisticated semiconductor model.
When simulating complex power electronic systems
Power electronics
Power electronics is the application of solid-state electronics for the control and conversion of electric power.-Introduction:Power electronic converters can be found wherever there is a need to modify a form of electrical energy...
, however, the processes during switching are of little interest. Here, it is more appropriate to use ideal switches that toggle instantaneously between a closed and an open circuit. This approach, which is implemented in PLECS, has two major advantages: Firstly, it yields systems that are piecewise-linear across switching instants, (thus resolving the otherwise difficult problem of simulating the non-linear discontinuity that occurs in the equivalent-circuit at the switching instant). Secondly, to handle discontinuities at the switching instants, only two integration steps are required (one for before the instant, and one after). Both of these advantages speed up the simulation considerably.