• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.12
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• pp.1537-1542
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• 2011

This paper presents the power management strategies for a compound hybrid excavator. The compound hybrid excavator has been replaced the hydraulic swing motor to the electric swing motor. This excavator requires a proper control algorithm to regulate the energy flow between the mechanical coupling and the electric devices. The controller should improve fuel economy and maintain the super capacitor voltage within a proper range. A thermostat controller and ECMS controller are designed such that these objectives can be achieved. The thermostat controller regulates the power of the engine-assist motor on the basis of the super capacitor voltage, and the ECMS controller determines it using the real-time fuel minimization strategy based on the concept of equivalent fuel. Simulation results showed that by using the hybrid excavator, the fuel economy becomes about 20% higher than that obtained using the conventional excavator and that the ECMS controller outperforms the thermostat controller.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.2
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• pp.211-217
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• 2015

Emission gas regulations and constantly increasing fuel costs call for the worldwide use of environmentally friendly and energy-efficient machines in industry. To meet these requirements, a hybrid excavator prototype has been developed that incorporates an electric swing motor, engine assist motor, and ultra-capacitor module into a conventional hydraulic excavator of the 22-ton class. This paper mainly describes a few techniques to optimize its energy efficiency. These include 1) controlling the engine speed in proportion to the load torque, 2) controlling the pump displacement when driving the electric swing system, 3) managing the ultra-capacitor voltage to minimize the electrical energy loss, and 4) reducing the cooling fan speed to improve the energy efficiency of the system.

• Proceedings of the KIEE Conference
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• 2008.10c
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• pp.111-113
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• 2008

본 논문에서는 복합형 하이브리드 굴삭기의 전력 변환 장치의 구조 및 제어 방법을 제안한다. 제안된 전력 변환 장치는 엔진 다이나모 장치를 이용하여 그 타당성을 입증하였으며, 제한된 실험 환경 내에서도 기존의 유압식 굴삭기와 비교하였을 때, 약 8% 정도의 연비 향상의 효쏙를 얻을 수 있었다. 현재 실제 굴삭기에 장착하여 성능과 연비 측정을 위한 실험이 진행 중이다.