Electric Work Vehicle Power Control Without a Low-Voltage Battery
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Solution Overview
Problem
Electric work vehicles require both high-voltage and low-voltage batteries, leading to space constraints and increased labor for battery replacement, as they need to shut off power to all components safely when stopped.
Innovation Solution
A control system that uses a high-voltage battery and a DC-DC converter to power both the traveling motor and control device, eliminating the need for a low-voltage battery by using a secondary start switch to maintain power to the main switch after initial energization, allowing safe system shutdown without a low-voltage battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a low-voltage battery is installed to power control devices, then the control system can be safely shut off, but the space for high-voltage battery is reduced and labor for battery replacement increases
Solution Approach 1:
The patent merges the functions of high-voltage and low-voltage power supplies into a single high-voltage battery system. The DC-DC converter steps down the high-voltage battery output to power control devices, eliminating the need for a separate low-voltage battery while maintaining safe shutdown capability through the main switch controlled by the control device.
Solution Approach 2:
The DC-DC converter acts as an intermediary between the high-voltage battery and control devices. It converts high-voltage battery power to appropriate voltage levels for control devices, enabling the high-voltage battery to directly power both high-voltage loads and control devices, thus eliminating the need for a separate low-voltage battery.
2Reliability
If a low-voltage battery is installed to power control devices, then the control system can be safely shut off, but the labor for battery replacement increases
Solution Approach 1:
The patent merges the functions of high-voltage and low-voltage power supplies into a single high-voltage battery system. The DC-DC converter steps down the high-voltage battery output to power control devices, eliminating the need for a separate low-voltage battery while maintaining safe shutdown capability through the main switch controlled by the control device.
3Volume of moving object
If only a high-voltage battery is used to power both traveling motor and control devices, then space is increased and battery replacement labor is reduced, but the control system cannot be safely shut off
Solution Approach 1:
The DC-DC converter acts as an intermediary between the high-voltage battery and control devices. It converts high-voltage battery power to appropriate voltage levels for control devices, enabling the high-voltage battery to directly power both high-voltage loads and control devices, thus eliminating the need for a separate low-voltage battery.
Solution Approach 2:
The control device powers itself from the high-voltage battery through the DC-DC converter, eliminating the need for external low-voltage battery support. The system achieves self-sufficiency with a single battery while maintaining full control functionality for safe shutdown operations.
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 reduces the need for a low-voltage battery, increases space for high-voltage batteries, and decreases labor for battery replacement, while ensuring safe system shutdown and stable charging operations.
Implementation Method 1
a DC-DC converter which steps down a voltage of the battery and outputs the voltage to the control device
Data Source
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AI summary
[Problem] In a control system for an electric work vehicle (10), a space for a size increase of other components such as a high-voltage battery is increased, and a labor for battery replacement is reduced by eliminating a need for mounting a low-voltage battery. [Solution] The control system (110) includes a traveling motor (20) to which power is fed from a battery (90) via a main switch (112), a control device (46) which controls an ON/OFF state of the main switch, and a first start switch (63) connected between an output side of a DC-DC converter (80) and the control device and is configured such that a primary side of the main switch is connected to an input side of the DC-DC converter with a second start switch (64) interposed, and the control device is started by an output voltage of the DC-DC converter by an operation of the second start switch to an energized position. The control device turns on the main switch and maintains the state when the second start switch is operated to an energized position and the first start switch is at an operation position to the energized position.