Fan Motor Control for Battery Power Reduction in Construction Machines

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Solution Overview

Problem

In electrically driven hydraulic excavators, the consumption of battery electric power by the fan electric drive device is not adequately managed, leading to inefficiencies when the lock lever is in the locked position, as existing technologies do not consider power reduction for the fan electric drive device.

Innovation Solution

Implementing a control system, such as an inverter unit with a fan control portion, that stops the fan electric drive motor when the lock lever is in the locked position, synchronizing this action with the stopping of the main electric drive motor, to limit battery electric power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the fan electric drive device operates continuously, then the heat exchanger can be cooled effectively, but the battery electric power consumption increases

Engineering Contradiction:
Improveheat exchanger coolingVSAvoidbattery electric power consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The fan electric drive device transitions from static continuous operation to dynamic conditional operation. The control system dynamically adjusts the fan motor operation state based on real-time detection of lock lever position, enabling the system to adapt between running and stopped states according to actual working conditions, thereby resolving the contradiction between continuous cooling and power consumption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses the lock lever position signal (already present in the operating system) to automatically control the fan electric drive device without requiring separate temperature sensors or additional control inputs. The fan motor self-regulates its operation based on the operational state of the excavator, eliminating unnecessary power consumption when the excavator is locked.

Inventive Principle:
Principle #25Self-service

2Reliability

If the fan electric drive motor runs during locked position, then cooling is maintained, but operating time of the excavator is reduced

Engineering Contradiction:
Improvecooling function availabilityVSAvoidoperating time
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The fan electric drive device implements dynamic state transitions based on lock lever position. When the lock lever is in the locked position, the fan motor automatically stops, extending operating time. When the lock lever is in the unlocked position, the fan motor runs to ensure cooling reliability. This dynamic adaptation resolves the contradiction between maintaining cooling function and extending operating time.

Inventive Principle:
Principle #15Dynamics

3Use of energy by moving object

If the fan electric drive device is controlled to stop when locked, then power consumption is reduced, but cooling may be insufficient during transition

Engineering Contradiction:
Improvebattery electric power consumptionVSAvoidcooling adequacy
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The control system continuously monitors the lock lever position and provides feedback control to the fan electric drive device. When the lock lever position changes from locked to unlocked, the system detects this change and activates the fan motor to ensure cooling is maintained. This feedback mechanism ensures cooling adequacy during transitions while maintaining power efficiency during stable locked states.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2581501B1Construction machine
Publication Date: 2019.03.13 HITACHI CONSTRUCTION MACHINERY TIERRA CO LTD
  • EP2581501B1 patent drawingFigure 1
  • EP2581501B1 patent drawingFigure 2
  • EP2581501B1 patent drawingFigure 3

AI summary

A construction machine that can limit consumption of battery electric power is provided. The construction machine includes: air-cooled heat exchangers 47, 48; a cooling fan 49 for generating cooling air for the heat exchangers 47, 48; a fan electric drive motor 50 that is driven by electric power of a battery 8 for rotating the cooling fan 49; an inverter unit 30 for drivingly controlling the fan electric drive motor 50; a lock lever 25 disposed at a boarding-alighting port and configured to be operated into an unlocked position and a locked position; and a lock valve 42 for making an operation of an operating device 27 or the like ineffective or the operating device inoperative when the lock lever 25 is operated into the locked position. The inverter unit 30 stops the fan electric drive motor 50 when the lock lever 25 is operated into the locked position.