Dynamic Performance Improvement and Peak Power Limiting Using Ultracapacitor Storage System for Hydraulic Mining Shovels

This paper presents a concept to improve the dynamic response, efficiency, productivity, and fuel consumption of hydraulic mining shovels (HMSs) using a high power energy storage system to supplement the existing diesel-powered generators. A 2.25-MW ultracapacitor system is applied to improve the sluggish dynamic response of the diesel engine during sudden load changes and to limit the engine power requirements by maintaining an optimal engine speed. When the load rate of change increases above a specified rate limit, the ultracapacitor system supplements power to support loads in order to limit the power ramp rate for the generator. In addition to the engine dynamic improvement, the ultracapacitor system supports the engine during peak power demand, allowing for a smaller engine size for the machine, which results in higher fuel savings and less exhaust emissions. An interleaved bidirectional dc/dc converter is designed to interface between the ultracapacitor bank and main dc bus. Sophisticated multilayer control strategies are designed, implemented, and applied to the system to perform complete machine power management while keeping the dc bus voltage stable. Modeling and experimental results for an 8000-hp HMS with the novel electrification architecture have also been presented.