Mining Vehicle Traction System Using Permanent Magnet Motor
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Solution Overview
Problem
Conventional electrically driven mining vehicles are limited by their dependency on a constant electricity supply, large and inflexible component sizes, and the inability to efficiently increase electric power for tramming due to the inherent characteristics of induction motors and mechanical transmissions.
Innovation Solution
The implementation of a mining vehicle with a traction mechanism powered by a permanent magnet AC motor, a traction DC/AC converter for flexible speed control, local electric energy storage, and a DC/DC converter for optimal voltage management, along with a battery charger and charge level controller to enable autonomous operation and efficient energy utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If induction motors are used for traction, then the vehicle can be connected to the electricity grid with a cable, but the motors become prohibitively large when high power is required
Solution Approach 1:
The patent replaces the conventional induction motor with a permanent magnet synchronous motor (PMSM). This substitution enables high power density because PMSMs can deliver the same power output in a much smaller volume compared to induction motors, directly resolving the contradiction between requiring high power and avoiding prohibitively large motor sizes.
2Ease of operation
If induction motors with mechanical transmission are used, then the vehicle can operate with a cable connection, but the driving speed becomes inflexible due to constant motor rotation rate
Solution Approach 1:
The patent replaces the mechanical transmission system with an electrical speed control system using a variable frequency drive (VFD) for the permanent magnet synchronous motor. This substitution provides flexible and continuous speed control by varying the electrical frequency supplied to the motor, eliminating the need for mechanical gears and achieving smooth acceleration and deceleration without the complexity of mechanical transmission components.
3Duration of action of moving object
If the vehicle operates with a cable connection to the electricity grid, then it can be powered continuously, but it becomes dependent on constant external power supply and requires towing when moving beyond cable reach
Solution Approach 1:
The patent segments the power supply system into two independent parts: the main electricity grid connection for continuous operation and an auxiliary onboard battery system for autonomous operation. This segmentation allows the vehicle to draw power from the grid when available while maintaining the capability to operate independently using battery power when moving beyond cable reach or in areas without grid connection, thereby extending operational range and improving adaptability.
4Reliability
If hydraulic pumps are connected directly to the transmission, then hydraulic power is always available, but power is wasted when the electric motor is not receiving power from the grid
Solution Approach 1:
The patent makes the hydraulic pump system dynamic by controlling its operation based on the actual power availability from the electric motor. The hydraulic pump is driven by the electric motor when power is available, and the system automatically adjusts or stops pump operation when the motor is not receiving power from the grid, ensuring hydraulic power is available when needed while avoiding energy waste during idle periods.
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 allows for a compact, powerful, and flexible driving mechanism with enhanced autonomy and energy efficiency, enabling the vehicle to operate without a constant external power source and utilize regenerated energy effectively.
Implementation Method 1
a traction motor for driving said traction mechanism
Implementation Method 2
a traction DC/AC converter for converting DC power from said DC power link into AC power for feeding into said traction motor
Implementation Method 3
local electric energy storage, and a DC/DC converter for optimal voltage management
Implementation Method 4
a DC/DC converter for optimal voltage management
Data Source
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AI summary
A mining vehicle comprises a traction mechanism for propelling the mining vehicle, a traction motor for driving said traction mechanism, a cable connection for connecting the mining vehicle to an external source of electric energy, and an electric power link between said cable connection and said traction motor for conveying electric energy from said cable connection to said traction motor. Said electric power link comprises a DC power link. The mining vehicle comprises a traction DC/AC converter for converting DC power from said DC power link into AC power for feeding into said traction motor.