Patent ID: 8225893

Claim:
A control apparatus for a hybrid vehicle including an engine operating by fuel combustion, a power split device connecting, in a relatively rotatable manner with respect to each other, a plurality of rotation elements respectively coupled to an output shaft of said engine, to an output shaft of a first motor generator and to an output member, and providing at least a portion of an output from said engine to said output member in accordance with input and output of electrical power and mechanical power by said first motor generator, a second motor generator applying mechanical power in a path from said output member to a driving wheel, and a power conversion unit connected to a power storage device and said first and second generators to carry out power conversion bidirectionally, said control apparatus comprising: a revolution speed detection unit for detecting a revolution speed of said first motor generator, a revolution speed reduction detection unit for detecting reduction in the revolution speed of said first motor generator according to reduction in output torque from said engine, based on the detected revolution speed of said first motor generator and a control signal of said engine, and a power balance control unit for controlling said power conversion unit such that a sum of input and output electrical power of said first and second motor generators is restricted to be within a predetermined range when reduction in the revolution speed of said first motor generator is detected by said revolution speed reduction detection unit, said power balance control unit modifying a control command to said power conversion unit such that overdischarging of said power storage device caused by reduction in electrical power generated by said first motor generator does not occur when reduction in the revolution speed of said first motor generator is detected by said revolution speed reduction detection unit.