Development Of Circuit Simulation Software Based On Qt

Circuit simulation technology is an important industrial software technology and is the foundation of the current electronic design system.Nowadays,most of the more mature circuit simulation software is foreign commercial software,and most of the open source software uses SPICE(simulation program with integrated circuit focus)simulator.Although the relevant theories are relatively mature,most studies only improve the existing circuit simulation technology in certain aspects,and few people implement the circuit simulation software as a whole.In response to the above problems,the dissertation has deeply studied the implementation principles of circuit simulation software,proposed an effective circuit simulation software framework,and developed open source circuit simulation software based on this framework.The main tasks of the dissertation are as follows:Firstly,in order to reduce the degree of coupling between the component model building program and other programs,the dissertation is based on the object-oriented development method,encapsulating the pins,nodes and connectors into independent objects,so that the interconnected pins are tied through the connector.Determine the node of the circuit based on this,and only allow data interaction between external programs and components through pins.The virtual inheritance mechanism of C++ is used to construct and visualize the mathematical model of each component,so that the construction of component model is open for extension and closed for modification,which conforms to the opening and closing principle in program design.For specific components,this study uses the Newton-Raphson method to linearize the nonlinear components,and the backward Euler method creates the corresponding equivalent circuit for the energy storage components in the transient analysis.Secondly,in order to enable the software to correctly describe the floating voltage source in the circuit,the dissertation uses the improved node method(MNA)to solve the circuit,and according to the contribution mechanism of different components to the MNA equation,a complete set of MNA nodes is designed Matrix equation construction system.Aiming at the sparsity of the MNA equation,the dissertation designed and wrote the corresponding decomposition and solving program based on the LU decomposition algorithm,and transferred the program to the adaptive solving function to deal with various circuit conditions.The realization of the above functions provides the necessary conditions for the construction of the software circuit simulator.Finally,in order to reduce the use cost of the software,the dissertation refers to the more mature circuit simulation software on the market,and has carried out a simple and intuitive layout of the software user interface.The user interface and circuit symbols are implemented in pure code,and the view and model are separated based on the MVC framework.The interface program uses the focus system to capture the position of the mouse pointer,responds to the mouse operation through the event mechanism and the signal and slot system,and provides visual feedback of the operation result through the interface,which realizes the human-computer interaction function of the software.Based on the Qt open source platform,the dissertation systematically developed an open source circuit simulation software that supports the custom addition of component models.The circuit simulation function of the software is tested through the RLC series circuit and the triode astable oscillation circuit,and the results show that the software can correctly simulate the corresponding circuit within the error tolerance range.It is of great significance to the development of domestic circuit simulation software.The dissertation is of great significance to the development of domestic circuit simulation software.