Styslo B. Semiconductor converters for systems with electrical energy storage devices

The dissertation is devoted to solving an important scientific and technical problem - the study of operation of semiconductor converters with electric energy storage systems. It is determined that one of the perspective directions of scientific work in this branch is the research and development of the operating modes of energy efficient converters working in conjunction with the battery energy storage systems (BESS). It is shown that the use of BESS in power supply systems requires the use of specialized energy-efficient converters. These converters are divided into matching converters, to provide connection BESS with the mains, and service converters that ensure safe operation mode of BESS. For service converters the analysis of the existing systems of balancing of series-connected batteries is made. The advisability of using the active balancing of storage batteries is justified. The energy efficiency of the use of capacitive and inductive buffer elements in active balancing converters is determined. The expediency of using transformer circuits of active balancing is proved. The principle of addressable transfer of the energy between the series connected batteries was proved. It is proved that this system allows increasing the efficiency of the balancing process due to the redistribution of missing and surplus energy between the batteries. The implementation of the control system of the addressable balancing system of the prediction type is proposed. It allows to obtain the main parameters of each of the series-connected electrical energy storage devices using a single voltage sensor. It is proved that optimization of the process of balancing by the criterion of energy efficiency allows to further improve the energy performance of the system, reducing static losses in power switches at each stage of balancing up to 70%. Synthesis of the structural scheme of a two-channel additional power source is performed. The possibility of using one low-frequency filter in the control system of two-channel BESS is proved. It generates control signals for matching converters, for servicing both low-frequency and high-frequency channels of BESS. Based on the analysis of switching processes in power switches of matching converters, the expediency of using separated-commutation converters that provide soft switching modes in semiconductor switches is proved. Four variants of realization of the matching converter are developed. On the basis of the techno-economic justification, the optimal converter circuit was chosen. A control system which implements the separated commutation algorithm for a matching converter is proposed. The realization of the fixed and variable time intervals between the control pulses of the power switches is assigned to the digital control system hardware. The algorithm of the control system operation, using the minimum number of sensors is proposed. Proposed algorithm allows to take into account the parameters of the load.