DE-112024002917-T5 - WORK MACHINE AND CONTROL METHOD FOR WORK MACHINE

Abstract

A working machine includes a power supply unit connected to an external power source and configured to supply power, a battery configured to be charged by charging power input from the power supply unit, an electrical device configured to consume power from at least one load input from the power supply unit and the battery, and a control unit. The control unit determines a first upper limit for the charging power, modifies the first upper limit into a second upper limit based on the load power, and controls the power supply unit so that the supply power follows the load power and the charging power does not exceed the first upper limit.

Inventors

• FUJIKAWA TAKUYA
• YOSHIDA TAKESHI

Assignees

• KOMATSU MFG CO LTD

Dates

Publication Date

20260507

Application Date

20240926

Priority Date

20230929

Claims (5)

1. Working machine comprising: a power supply unit connected to an external power supply and configured to supply power; a battery configured to be charged by charging power input from the power supply unit; an electrical device configured to consume load power input from the power supply unit and the battery; and a control unit, wherein the control unit determines a first upper limit of the charging power, modifies the first upper limit into a second upper limit based on the load power, and controls the power supply unit so that the supply power follows the load power and the charging power does not exceed the first upper limit.
2. Working machine according to Claim 1 , wherein the control unit receives information about the battery power limit from the battery and determines the first upper limit based on the battery power limit information.
3. Working machine according to Claim 2 , where the second upper limit is the sum of the first upper limit and a current value of the load power.
4. Working machine according to Claim 1 , wherein the electrical device includes an electric motor, the battery is charged by regenerative electrical power input from the electric motor, and the control unit controls the power supply unit so that the supply power follows the load power and the charging power does not exceed the first upper limit.
5. A control method for a working machine, including a power supply unit connected to an external power supply, a battery charged by the power supply unit, and an electrical device, wherein the control method comprises: causing the power supply unit connected to the external power supply to deliver power; charging the battery with charging power input from the power supply unit; inputting load power to the electrical device from at least one source, the power supply unit, and the battery; determining a first upper limit of the charging power; changing the first upper limit to a second upper limit based on the load power; and controlling the power supply unit such that the power supply follows the load power and the charging power does not exceed the first upper limit.

Description

TECHNICAL AREA The present disclosure relates to a working machine and a control method for a working machine. STATE OF THE ART A construction machine is known that is powered by electrical energy from a battery. If the machine is operated solely with the electrical energy supplied by the battery, its operating time may be insufficient. If a large-capacity battery is mounted on the machine to counteract this reduction in operating time, the battery can occupy most of the machine's space, increasing its size. Furthermore, the cost of the machine can increase if a large-capacity battery is installed. By operating the machine using both electrical energy supplied from an external power supply and electrical energy supplied from the battery, it is possible to extend the operating time and reduce the battery capacity. Patent document 1 discloses a construction machine that uses both electrical energy supplied from an external power supply and electrical energy supplied from a battery. LIST OF COUNTERPOINTMENTS Patent literature Patent document 1: JP 2022-109029 A BRIEF SUMMARY OF THE INVENTION Technical problem Operating the machine with electrical power supplied from an external power source reduces the battery's charge/discharge rate, thus potentially preventing a reduction in battery lifespan. Conversely, if a low-capacity battery is installed to minimize the space occupied by the battery, the ratio of charge/discharge rate to battery capacity increases, which can shorten the battery's lifespan. One purpose of the present disclosure is to suppress a reduction in the service life of a battery in a working machine that uses both an external power supply and the battery. Solution to the problem According to the present disclosure, a working machine is provided which includes a power supply unit connected to an external power supply and configured to output power, a battery configured to be charged with charging power input from the power supply unit, an electrical device configured to consume power from at least one load input from the power supply unit and the battery, and a control unit. The control unit determines a first upper limit of the charging power, changes the first upper limit to a second upper limit based on the load power, and controls the power supply unit so that the power supply follows the load power and the charging power does not exceed the first upper limit. Advantageous effects of the invention According to the present disclosure, it is possible to suppress a reduction in the battery's lifespan in a working machine that uses both an external power supply and a battery. BRIEF DESCRIPTION OF THE DRAWINGS 1 is a representation that illustrates a working machine according to one embodiment.2 is a block diagram illustrating the working machine according to the embodiment.3 is a hardware configuration scheme illustrating a control unit according to the embodiment.4 is a representation to describe an operating procedure for the working machine according to the embodiment.5 is a block diagram illustrating the control unit according to the embodiment.6 is a flowchart illustrating a control procedure for the working machine according to the embodiment.7 is a graph that shows a relationship between supply power, charging power and load power according to the embodiment.8 is a graph that shows the relationship between the supply power, the charging power and the load power according to the embodiment.9 is a graph that shows the relationship between the supply power, the charging power and the load power according to the embodiment.10 is a graph that shows a relationship between the supply power, the charging power and the load power in the generation of regenerative electrical power according to the embodiment.11 is a graph showing the relationship between the supply power, the charging power and the load power in the generation of regenerative electrical power according to the embodiment. DESCRIPTION OF EXECUTION FORMS The following are embodiments according to the present disclosure; however, the present disclosure is not limited to these embodiments. Components of each of the embodiments described below can be combined appropriately. In some cases, some components are not used. work machine 1 Figure 1 is a diagram illustrating a working machine 1 according to the embodiment. In this embodiment, the working machine 1 is an electric working machine with an external power supply 8 and a battery 7 as drive sources. In this embodiment, the working machine 1 is an electric excavator. The working machine 1 includes a lower drive body 2, an upper rotating body 3, a working attachment 4, a hydraulic actuator 5, a power supply unit 6, and the battery 7. The lower drive unit 2 includes a pair of continuous crawler tracks. The lower drive unit 2 is capable of driving on the ground. The upper rotating unit 3 is supported by the lower drive unit 2. The upper rotating unit 3 is capable of rotating. The working uni