Analysis of different control strategies and operating modes of compact high planetary transmission drive

This paper presents the original compact hybrid planetary transmission drive (CHPTD) as a solution of hybrid drive for urban bus. CHPTD uses only one motor. Planetary gear with two degrees of freedom is directly connected with the motor and internal combustion engine (ICE), which explains its compact construction. The third shaft of planetary gear via differential gear propels traction wheels. The clutch-brake system of CHPTD can reduce the planetary gear degrees of freedom, which permits to obtain three operating modes of hybrid drive system: hybrid, pure electric and pure engine. These operating modes provide possibilities for different bus drive, depending on vehicle starting way, downtown or suburban operations. The flexibility of CHPTD application permits properly adjusting power distribution and splitting power between battery and engine, which is the reason of very efficient driving. CHPTD as a kind of "optimized hybrid drive" consumes significantly less energy (fuel and electricity) than well-known series hybrid drive.