A Simulink model is considered that allows calculating transient processes of objects described using a transient function for any type of input action. An algorithm for the operation of the S-function that performs calculations using the Duhamel integral is described. It is shown that due to the features of the S-function, it can store the values of the previous step of the Simulink model calculation. This allows the input signal to be decomposed into step components and the time of occurrence of each step and its value to be stored. For each step of the input signal increment, the S-function calculates the response by scaling the transient response. Then, at each step of the calculation, the sum of such reactions is found. The S-function provides a procedure for freeing memory when the end point of the transient response is reached at each step. Thus, the amount of memory required for the calculation does not increase above a certain limit, and, in general, does not depend on the length of the model time. For calculations, the S-function uses matrix operations and does not use cycles. Due to this, the speed of model calculation is quite high. The article presents the results of calculations. Recommendations are given for setting the parameters of the model. A conclusion is formulated on the possibility of using the model for calculating dynamic modes.

Keywords: simulation modeling, Simulink, step response, step function, S-function, Duhamel integral.

The modeling of a multi-motor linear electric drive of a conveyor train is considered. A diagram of the simulation model made in the Simulink program is given. Graphs of the speed and force of the electric drive during the relay transmission of the secondary element are given. The conclusion is formulated that the system fulfills the requirements placed on it.

Keywords: simulation modeling, Simulink, linear asynchronous motor, electric drive, conveyor train, relay transmission

Simulation modeling of protective circuits of a DC transistor electronic device is considered. It is shown that simulation modeling is one of the advanced research methods. The application of the Simulink program for this purpose is justified. The transistor switching device is considered from the point of view of overvoltages arising when the current is switched off. A simplified circuit of the switching device necessary for conducting research is given. A complete diagram of the Simulink model is given. Protection schemes using resistors, capacitors and varistors are given. The magnitude of overvoltages on a transistor with a different combination of protective circuits is investigated. The dependences of the overvoltage magnitude on the switched current for various combinations of protective circuits are given. The dependences of the overvoltage magnitude on the parameters of the elements of the protective circuits are given. The conclusion about the necessary structure of protective circuits is formulated.

Keywords: simulation, Simulink, switching device, overvoltage, transistor, protective circuit, varistor