Modeling Method for Autonomous Current Inverters

Modern development of converter engineering is connected with creation of autonomous electric energy converters and their application in various branches of industry. In most cases high requirements are set for reliability and technical performance of such converters. This type of converters are complex non-linear systems, so their in-depth research is impossible without a detailed description of processes based on their exact mathematical models. An important condition of model development is its ability to perform calculations of various dynamic transients to choose the optimal parameters of the circuit, providing the fulfilment of requirements of technical specification. The paper applies the method of mathematical modelling of valve electric circuits with piecewise linear approximation of valve characteristics. We propose the method of the mathematical modelling of valve converter based on autonomous current inverters (ACI), which is based on identifying all possible states of the converter power circuit followed by the formation of universal equivalent circuits of several states of the converter power circuit. Recurrence formulas for the required currents and voltages corresponding to each conductivity interval of the valve elements are presented. The proposed methodology of transient analysis of instantaneous currents and voltages in an autonomous current inverter is based on the Laplace transform rules. It can be used to calculate steady-state as well as transients in various types of valve inverters, regardless of the complexity of the power circuit, the load type, and control system features.