Предложен вариант модернизации цепей питания вспомогательных электроприводов электропоездов ЭД9М путём замены электромашинного фазорасщепителя на статический преобразователь. Разработан преобразователь позволяющий без значительных изменений в схеме питания вспомогательных электроприводов электропоезда ЭД9М повысить их мощность до 43 кВт без увеличения токовой нагрузки обмотки питания собственных нужд тягового трансформатора. Выявлены особенности управления трехфазным инвертором при наличии пульсации 100 Гц в звене постоянного тока. A variant of upgrading the power supply circuits of auxiliary electric drives of ED9M electric trains by replacing a rotary phase converter with a static converter has been proposed. A single-phase active rectifier circuit is proposed, which makes it possible to ensure fast chargingof the output capacitor. A converter has been developed that allows, without significant changes in the power supply circuit of auxiliary electric drives of the ED9M electric train, to increase their power to 43 kW. The features of three-phase inverter control in the presence of a 100 Hz pulsation at its input are revealed. As a result of tests, it was shown that by increasing the power factor and the efficiency of a static converter, it is possible to solve the problem of increasing active power while maintaining the total power consumption of theauxiliary winding of the transformer. Test results of the proposed upgrading scheme are reported.