Increasing the efficiency of the regenerative braking mode of ac electric carriers by excluding the ballast resistance from its power circuit

One of the tasks of JSC Russian Railways in the Strategy for Scientific and Technological Development of Russian Railways Holding for the Period up to 2025 and in the Long Term until 2030 is to reduce the specific consumption of electric energy by electric rolling stock and increase its energy efficiency. Domestic electric locomotives of alternating current operating today on the railways of Russia have unsatisfactory energy indicators both in traction mode and in regenerative braking mode. In the recuperation mode, there is a significant consumption of reactive electricity by an electric locomotive from the contact network, and, as a result, an extremely low power factor, not exceeding 0.65 at the highest voltage regulation zone. The presence of blocks of ballast resistors in the power circuit, which is directly related to the adopted law of control of rectifier-inverter converters, not only limits the range of braking characteristics of the electric locomotive, but also significantly reduces the amount of electricity supplied to the overhead. In this article, the authors considered a modern approach to solving the issue of the energy efficiency of an electric locomotive in the recuperation mode, namely: the use of a rectifier-inverter converter based on IGBT transistors and the development of a method for implementing regenerative braking without blocks of ballast resistors with ensuring the electrical stability of this mode. For the purpose of analytically proving the operability of this method, the external characteristics of an inverter based on IGBT transistors are presented, the positive slope of which indicates the possibility of implementing the regenerative braking mode without ballast resistance. The developed method will make it possible to save about 880 thousand rubles from one electric locomotive of the 2ES5K series. in year.