Simplified DC Link Topology for Trolley Assist Mining Trucks
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Solution Overview
Problem
Existing DC link topologies for trolley assist-capable electric drive trucks are complex and require multiple contactors to facilitate different operational modes, which can increase costs and operational complexity in energy-intensive mining environments.
Innovation Solution
A simplified DC link topology using exactly three contactors that can be switched between open and closed circuit configurations to manage electrical power routing for normal and trolley modes of propulsion and retarding, reducing the number of contactors needed compared to prior art.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple contactors are used to facilitate different operational modes in DC link topology, then the system can support both onboard and trolley power sources, but the device complexity increases
Solution Approach 1:
The patent applies multi-functionality by designing contactors that can serve multiple operational modes (onboard power, trolley power, regenerative braking) rather than requiring separate dedicated contactors for each mode. The DC link topology enables a single contactor configuration to handle diverse power flow scenarios including propulsion, retarding, and power conversion between different sources.
Solution Approach 2:
The patent combines multiple functional requirements into a unified DC link topology with a specific arrangement of three contactors that simultaneously manage onboard power source connection, trolley power source connection, and regenerative braking power conversion. This merging of functions reduces the total number of contactors needed compared to separate dedicated circuits for each operational mode.
2Adaptability or versatility
If multiple contactors are used in DC link topology, then different operational modes can be facilitated, but the manufacturing cost increases
Solution Approach 1:
The patent merges multiple operational mode requirements into a single integrated DC link topology using exactly three contactors. This consolidation reduces the bill of materials and manufacturing complexity compared to alternative topologies that use four or more contactors, while still achieving full operational versatility including onboard power mode, trolley power mode, and regenerative braking mode.
Solution Approach 2:
The contactor arrangement in the patent achieves universal functionality where the same three contactors handle multiple power sources and operational modes, reducing the need for mode-specific hardware and thereby lowering overall manufacturing costs while maintaining adaptability across all required operational scenarios.
3Adaptability or versatility
If multiple contactors are used to manage power routing, then operational flexibility is improved, but the operational complexity increases
Solution Approach 1:
The patent applies local quality by assigning specific, non-overlapping functions to each of the three contactors in the DC link topology. Each contactor has a defined role in power routing (e.g., connecting onboard power, connecting trolley power, enabling regenerative braking), which simplifies control logic compared to more complex topologies where contactors may need to coordinate in multiple overlapping configurations to achieve the same operational flexibility.
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 solution allows for efficient energy management and reduced operational complexity by enabling seamless transitions between onboard and trolley power sources, optimizing energy use and cost efficiency in mining trucks.
Implementation Method 1
an internal combustion engine mechanically coupled to an electrical power generator
Implementation Method 2
At least one electric propulsion motor is coupled to the ground engaging elements
Implementation Method 3
The positive direct current conductor is electrically separated from the negative direct current conductor by the first contactor, a third contactor, a grid resistor and the second contactor
Data Source
AI summary
A trolley assist-capable electric drive truck includes a DC link with first, second and third contactors that may be opened and closed in different configurations to operate the truck in different modes. In a normal propel mode, the three contactors are open and electrical power is routed from an onboard electrical power source to electric propulsion motors. During normal retard mode, the three contactors are closed to route electrical energy generated by the electric propulsion motors through a grid resistor of the DC link. In a trolley mode, the first and second contactors are closed, but the third contactor is open, and electrical power is routed from the trolley lines to the motors for propulsion, or in a reverse direction for retarding the truck.