Abstract: A drive system for a hybrid vehicle comprises a differential including a planetary gear set having a plurality of rotating elements and at least one engagement element. At least one rotating element is connected to each of, a first motor generator, an engine, a drive wheel and a second motor generator. The at least one engagement element selectively provides a variable speed ratio mode and a fixed speed ratio mode for the differential. The first motor generator generates electric power from output power of at least one of the engine and the second motor generator in the variable speed ratio mode. The drive system further includes a controller that selects the variable speed ratio mode to charge a battery of the hybrid vehicle when a state of charge of the battery is lower than a predetermined value.