울트라 커패시터를 고려한 직렬형 하이브리드 차량의 상위제어 알고리즘에 관한 연구

Abstract

본 논문은 고기동성 하이브리드 군용차량의 상위제어 알고리즘에 대해서 연구하였다. 대상 차량은 직렬형 하이브리드 차량(Series Hybrid Electric Vehicle, SHEV)으로 전륜과 후륜 각각에 구동모터가 장착되고, 구동모터를 동작시키기 위해 필요한 전기적인 에너지는 세 가지의 에너지원(엔진/발전기, 배터리, 울트라 커패시터)을 통해서 공급하게 된다. 본 논문에서는 대상 SHEV이 주어진 임무에 따라 동작할 수 있도록 제어하기 위하여 상위제어 알고리즘의 구조를 제안하였고, 특히 연비 향상을 위해서 전/후륜 구동모터의 최적 요구 토크 분배 전략 및 세 가지의 에너지원의 다양한 파워 분배 전략(Thermostat, Power-follower, ECMS)에 대해 연구하였다. 제안한 상위제어 알고리즘은 크게 4가지 부분(운전자 의도파악, 최적 토크 분배, 차량 운전 모드 결정, 에너지원 파워 분배)으로 나뉘어진다. 운전자 의도 파악(Driver’s Intent Estimation) 알고리즘은 사용자의 입력과 차량의 상태를 통하여 운전자의 요구 토크를 계산하고 차량 운전 모드 결정에 필요한 플래그를 생성하게 된다. 최적 모터 토크 분배(Optimal Motor Torque Distribution) 알고리즘은 운전자의 요구토크를 전/후륜 모터에 분배하는 부분으로, 주어진 요구토크를 만족하고 구동 모터에서 필요로 하는 전기적인 파워를 최소화하도록 전/후륜 구동 모터에 토크를 분배하게 된다. 차량 운전 모드 결정(Vehicle Operating Mode Determination) 알고리즘은 운전자 의도 파악 알고리즘에서 생성한 플래그를 이용하여 에너지 모드와 차량 모드를 결정하게 된다. 에너지 모드는 차량 구동 시 필요한 에너지를 어떤 에너지원에서 생성하는지에 대한 정보를 생성하고, 차량 모드는 차량을 추진시킬 것인지 제동할 것인지에 대한 정보를 생성한다. 에너지원 파워 분배(Source Power Distribution) 알고리즘에서는 차량 운전 모드와 전/후륜 토크 분배에 따라서 두 구동 모터에서 필요로 하는 전기적인 파워를 세 가지의 에너지원에 분배한다. 본 논문에서는 에너지원 파워 분배와 관련하여 울트라 커패시터를 에너지원으로 사용하는 대상 SHEV 에 적합한 파워 분배 제어 전략을 제시한다. 본 논문에서 제안한 상위제어 알고리즘의 유효성을 확인하기 위하여 시뮬레이션을 수행하였다. 시뮬레이션 환경은 AVL CRUISE?? 로 프로그래밍된 대상 차량 모델과 MATLAB/Simulink?? 로 프로그래밍된 상위제어 알고리즘로 구성되며, Co-simulation을 통해. 속도 프로파일의 추종 성능, 임무 수행 성능, 그리고 연비 성능의 우수성을 확인하였다.|This paper proposes a new supervisory control algorithm for a high mobility hybrid electric military vehicle. The target hybrid electric vehicle is the series hybrid electric vehicle(SHEV) and consists of two driving motors at the front/rear axles and three energy sources(engine/generator set, battery, ultra-capacitor) which generate the electrical power to supply driving motors. This paper proposes a structure of the supervisory control algorithm to control the target vehicle for well operating at given mission. Also, for improving the fuel economy, a optimal torque distribution strategy and three source power distribution strategies(Thermostat, Power-follower, ECMS) are researched. The proposed supervisory control algorithm is classified into three four parts - driver’s intent estimation, optimal motor torque distribution, vehicle operating mode determination, source power distribution. In driver’s intent estimation algorithm, driver’s request torque and flags which are necessary information in vehicle operating mode determination algorithm are generated by using the vehicle’s state information and driver’s input. In optimal motor torque distribution algorithm, driver’s request torque is distributed to two driving motors. In this strategy, not only satisfy the driver’s request torque but also minimize the electrical power which is supplied to driving motors. In vehicle operating mode determination algorithm, proper hybrid system operating modes are determined based on the flags which are generated in driver’s intent estimation algorithm. This algorithm consists two vehicle operating mode - energy mode, driving mode. The energy mode represents which energy sources are used to generate the appropriate electric power. The driving mode represents the vehicle driving condition such as traction, braking. In source power distribution algorithm, the electrical powers which are supplied to two traction motors are distributed to three energy sources according to vehicle operating mode. In this paper proposed the source power distribution strategies with considering the ultra-capacitor. The simulation is performed for validity of proposed supervisory control algorithm. The simulation vehicle model of the target vehicle is developed by AVL CRUISE?? and the proposed supervisory control algorithm is realized by using the MATLAB/Simulink. Simulation results show the feasibility and effectiveness of the proposed algorithm.; This paper proposes a new supervisory control algorithm for a high mobility hybrid electric military vehicle. The target hybrid electric vehicle is the series hybrid electric vehicle(SHEV) and consists of two driving motors at the front/rear axles and three energy sources(engine/generator set, battery, ultra-capacitor) which generate the electrical power to supply driving motors. This paper proposes a structure of the supervisory control algorithm to control the target vehicle for well operating at given mission. Also, for improving the fuel economy, a optimal torque distribution strategy and three source power distribution strategies(Thermostat, Power-follower, ECMS) are researched. The proposed supervisory control algorithm is classified into three four parts - driver’s intent estimation, optimal motor torque distribution, vehicle operating mode determination, source power distribution. In driver’s intent estimation algorithm, driver’s request torque and flags which are necessary information in vehicle operating mode determination algorithm are generated by using the vehicle’s state information and driver’s input. In optimal motor torque distribution algorithm, driver’s request torque is distributed to two driving motors. In this strategy, not only satisfy the driver’s request torque but also minimize the electrical power which is supplied to driving motors. In vehicle operating mode determination algorithm, proper hybrid system operating modes are determined based on the flags which are generated in driver’s intent estimation algorithm. This algorithm consists two vehicle operating mode - energy mode, driving mode. The energy mode represents which energy sources are used to generate the appropriate electric power. The driving mode represents the vehicle driving condition such as traction, braking. In source power distribution algorithm, the electrical powers which are supplied to two traction motors are distributed to three energy sources according to vehicle operating mode. In this paper proposed the source power distribution strategies with considering the ultra-capacitor. The simulation is performed for validity of proposed supervisory control algorithm. The simulation vehicle model of the target vehicle is developed by AVL CRUISE?? and the proposed supervisory control algorithm is realized by using the MATLAB/Simulink. Simulation results show the feasibility and effectiveness of the proposed algorithm.