Dump Truck Power Switching Control for Overhead Line Transitions
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Solution Overview
Problem
Trolley rechargeable type electric drive vehicles experience adverse effects when switching power sources between battery power and overhead line power, requiring a solution to minimize these impacts.
Innovation Solution
The vehicle incorporates a power converter that can operate in voltage control or electric power control states, a current collector, and a switch unit controlled by a device to manage transitions smoothly, limiting output currents and voltages during power source switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the power supply source is switched from battery to overhead line or vice versa, then the vehicle can utilize different power sources for operation, but adverse effects occur during the switching process
Solution Approach 1:
The control device performs preliminary actions by controlling the converter to gradually reduce its output current to zero before completing the power source switching. This preparatory step ensures that when the overhead line is connected or disconnected, there is no sudden current surge or interruption that could destabilize the vehicle operation. The converter's output current is smoothly transitioned from battery power to overhead line power (or vice versa) through this preliminary reduction action.
Solution Approach 2:
The system employs dynamic control of the converter during the switching process. The converter operates in different modes (voltage control state and electric power control state) and transitions between them dynamically. The control device adjusts the converter's operation in real-time based on the switching stage, ensuring smooth power transfer and maintaining system stability throughout the transition from one power source to another.
2Power
If the converter operates in voltage control state with battery power, then voltage conversion is achieved, but direct connection to overhead line causes adverse effects
Solution Approach 1:
The control device applies preliminary anti-action by preemptively reducing the converter's output current to zero before the overhead line connection is established. This counteracts the potential harmful effect of sudden current surge that would occur if the converter remained in voltage control state with full output when the overhead line was connected. The principle prevents the adverse effect by acting in advance to neutralize the potential problem.
Solution Approach 2:
The converter acts as an intermediary device between the battery and the overhead line. During switching, it mediates the power transfer by gradually transitioning its operation from voltage control to electric power control state, controlling the flow of current to prevent sudden surges or interruptions. This intermediary function protects the system from adverse effects during the power source transition.
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 approach allows for seamless transitions between battery and overhead line power sources, reducing adverse effects on the vehicle and ensuring stable operation.
Implementation Method 1
a converter capable of operating in any one of: a voltage control state where the converter is connected to the power converter, the DC power from the battery is input, an input voltage is converted, and the DC power of the converted voltage is output to the power converter; and an electric power control state where the DC power from the overhead line is input, the input voltage is converted, and the DC power of the converted voltage is output to the battery
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A dump truck comprises a control device and a DCDC converter that outputs power to a power converter. When switching a power supply source to an electric motor from a battery to an overhead line, the control device operates the DCDC converter in an overhead line connection stable waiting state, and then operates the DCDC converter in a power supply switching processing state. The control device switches, when switching the power supply source to the electric motor from the overhead line to the battery, the DCDC converter operating in the power control state from the power control state to a voltage control state, and operates, after operating the DCDC converter in a first overhead line separation preparation state that limits an output current output to the power converter to zero, the DCDC converter in a second overhead line separation preparation state in which the output current output from the DCDC converter to the power converter increases toward a target value.