Mining Vehicle Reactive Power Compensation via Star-Delta Capacitor Switching
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Solution Overview
Problem
Mining vehicles in mines face issues with combustion engines, including noise, space occupancy, maintenance needs, and fire safety concerns due to hot surfaces and flammable fuels, while electrically powered vehicles are restricted by cable movement and reactive power compensation challenges.
Innovation Solution
A mining vehicle equipped with a three-phase AC electric motor, a current reducer unit using single-phase capacitor units for reactive power compensation, and a power electronics device for adjusting the power factor, allowing connection to different supply grids with varying nominal voltages through delta or star connections, and an auxiliary energy source for flexible energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a combustion engine is used for transfer drives, then driving energy is obtained without cable restrictions, but exhaust gases and noise cause problems, space is occupied, maintenance is required, and fire safety risks increase
Solution Approach 1:
The patent replaces the combustion engine (mechanical system) with an electric motor powered by electricity from the mine's electrical network. This substitution eliminates exhaust gases and noise while providing sufficient driving energy for transfer drives between work sites, resolving the contradiction between operational capability and harmful emissions.
2Use of energy by moving object
If mining vehicles are continuously connected to the electrical network, then electric power is provided for operations, but the vehicle is bound to the electrical network or cable
Solution Approach 1:
The patent segments the energy supply system into two distinct functions: electric power from the network is used for work phase operations (drilling, etc.), while a separate combustion engine provides independent driving energy for transfer drives. This segmentation allows the vehicle to perform work operations using clean electric power while maintaining mobility independence during relocation.
3Device complexity
If a single electric motor is used for both lower and higher supply voltages, then device complexity is reduced, but reactive power compensation becomes challenging
Solution Approach 1:
The patent employs a universal current reducer unit with capacitor banks that can function across both lower voltage (delta connection) and higher voltage (star connection) configurations. The same physical compensation device adapts to different operating conditions, providing reliable reactive power compensation without requiring separate systems for each voltage level, thus maintaining both simplicity and reliability.
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
Enables efficient and flexible energy supply to mining vehicles, reducing noise, space requirements, and fire risks, while maintaining reliable operation across different voltage levels and power conditions, minimizing reactive power issues and enhancing power factor.
Implementation Method 1
The current reducer unit comprises at least three single phase capacitor units. The three single phase capacitor units are connected to delta connection while the motor is connected to delta connection, and the three single phase capacitor units are connected to star connection while the motor is connected to star connection.
Data Source
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AI summary
The invention relates to a mining vehicle and to a method for energy supply of a mining vehicle. The mining vehicle comprises at least one mining work device, at least one three phase AC electric motor for powering the at least mining work device, a three phase connecting device connectable to a supply cable for supplying electric current to the mining vehicle from a supply grid and a current reducer unit for compensating for reactive power. The electric motor is connectable to delta connection and to star connection. The current reducer unit comprises at least three single phase capacitor units that are connectable to delta connection while the motor is connected to delta connection and connectable to star connection while the motor is connected to star connection.