Research on the drive system and logic threshold control strategy of the hybrid power gas engine heat pump

Gas engine heat pump is an important distributed power supply system in the energy structure. Hybrid power technique plays an important role in improving the engine performance and the gas conversion efficiency of gas engine heat pump (GEHP). In this paper, a design method of a hybrid power drive system is presented, including the selection method of drive type, and the selection of power hybrid approach. The relation between gas loss coefficient and the equivalent efficiency of drive system has been analyzed. The results show that the most suitable drive type is parallel-type. The optimum hybridization degree is 0.412; the rated power of motor is 8.75 kW. Based on the design method of the drive system, logic threshold control strategy is implemented in the hybrid power gas engine heat pump (HPGHP) system, which is composed of the switching law of transmission and the torque control of motor. According to the experimental verification, the gas consumption rate of gas engine can be controlled to be below 330 g/kWh. The gas conversion efficiency can increase about 7.6% when the logic threshold control strategy is used in the HPGHP system.