Hybrid Power System for Load-Lifting Apparatuses
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Solution Overview
Problem
Current load-lifting apparatuses, such as RTG cranes, suffer from low fuel efficiency and high emissions due to oversized diesel engines and inefficient energy storage systems, with existing hybrid solutions lacking regenerative braking capabilities and large battery packs to manage peak power surges effectively.
Innovation Solution
A hybrid power system for load-lifting apparatuses incorporating a DC bus architecture with a motor, energy storage unit, prime power system, and control system that allows regenerative braking energy to be stored and reused, utilizing various prime power sources and energy storage systems like battery packs, capacitors, and flywheels, with the prime power system rated power ratio to peak power between 0.2 and 0.7.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an oversized diesel engine is used to provide peak power bursts, then the power requirement is met, but fuel efficiency deteriorates and emissions increase
Solution Approach 1:
The power system is segmented into multiple components: a smaller diesel engine, a battery pack for peak power, and a regenerative braking system. This segmentation allows each component to operate in its optimal range, with the battery handling peak demands and the engine providing base power, improving overall fuel efficiency while meeting peak power requirements.
Solution Approach 2:
Energy is stored in the battery pack in advance during regenerative braking phases and low-demand periods. This preliminary energy storage allows the system to meet peak power demands without requiring an oversized engine, as the pre-stored energy is discharged when needed.
2Loss of energy
If regenerative braking is implemented, then energy recovery is improved, but system complexity increases
Solution Approach 1:
The motor is designed to serve multiple functions: it acts as a motor during lifting operations and as a generator during regenerative braking. This multi-functionality enables energy recovery without adding separate braking systems, thereby reducing overall system complexity while improving energy recovery.
Solution Approach 2:
The system recovers energy during lowering operations when the load descends, converting gravitational potential energy back into electrical energy that charges the battery. This self-service mechanism captures otherwise wasted energy during necessary operational phases, improving energy recovery with minimal additional complexity.
3Use of energy by moving object
If a hybrid power system with energy storage is used, then fuel efficiency is improved, but device complexity increases
Solution Approach 1:
The battery pack, regenerative braking system, and diesel engine are merged into a unified hybrid power system with integrated control. This combination allows the components to work synergistically, improving fuel efficiency through coordinated operation while managing complexity through integration rather than separate systems.
Solution Approach 2:
The control system continuously monitors system state and adjusts power distribution between the engine and battery based on real-time conditions. This feedback mechanism optimizes fuel efficiency by dynamically managing energy sources, while the intelligent control compensates for the added complexity through automated decision-making algorithms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances fuel efficiency, reduces noxious emissions, and allows for quiet operation in confined spaces by leveraging energy storage to alleviate peak power demands, while distributing components for stability and ease of service.
Implementation Method 1
the motor selectively receives operational energy from the energy storage unit and the prime power system, and supplies regenerative braking energy to the bus when the load-lifting device lowers a load
Implementation Method 2
at least one energy storage unit for storing electric energy and supplying the electric energy to the at least one motor
Data Source
AI summary
A load-lifting apparatus has one or more prime power sources, one or more energy storage systems and regenerative braking. Regenerative energy is recovered when the load-lifting apparatus lowers its load. The elements of the prime power sources, energy storage devices and electrical components may be distributed to provide stability for the load-lifting apparatus. The general power architecture and energy recovery method can be applied to cranes, rubber-tired gantry cranes, overhead cranes, mobile cranes, ship-to-shore cranes, container cranes, rail-mounted gantry cranes, straddle carrier cranes and elevators. In such an architecture, the energy storage system helps alleviate the power rating requirement of the prime power source with respect to the peak power requirement for lifting a load.