HYBRID VEHICLE DRIVE SYSTEM

A drive system of a hybrid vehicle including an internal combustion engine, a first motor-generator, a second motor-generator, a planetary gear mechanism provided in a power transmission path, a clutch mechanism engaging or disengaging a sun gear and ring gear of the planetary gear mechanism, and a microprocessor controlling the clutch mechanism. The microprocessor is configured to determine whether it is necessary to perform a meshing position shifting control for shifting meshing positions of the sun gear and the planetary gear and of the planetary gear and the ring gear, and temporarily disengage the clutch mechanism so as to shift the meshing positions when it is determined that it is necessary to perform the meshing position shifting control while the clutch mechanism is engaged.