A PORTABLE POWER SUPPLY SYSTEM FOR AN ELECTRICALLY DRIVEN WORK MACHINE AND A WORK MACHINE EQUIPPED WITH SUCH A POWER SUPPLY SYSTEM

• US 20150136505A1
• Filed: 04/19/2013
• Published: 05/21/2015
• Est. Priority Date: 04/23/2012
• Status: Active Grant

• Current Assignee: Brokk Aktiebolag
• Original Assignee: Brokk Aktiebolag
• Inventors: Bystedt, Gunnar
• Granted Patent: US 9,725,879 B2
• Time in Patent Office: Days
• US Class Current: 180/167
• CPC Class Codes: B60L 15/20 for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
• CPC Class Codes: B60L 15/40 Adaptation of control equipment on vehicle for remote actuation from a stationary place devices along the route for controlling devices on rail vehicles B61L3/00; central rail-traffic control systems B61L27/00
• CPC Class Codes: E02F 3/966 of hammer-type tools arrangements for breaking-up hard ground E02F5/305; percussion -type rippers E02F5/323
• CPC Class Codes: E02F 9/2004 Control mechanisms, e.g. control levers control levers per se G05G
• CPC Class Codes: E02F 9/205 Remotely operated machines, e.g. unmanned vehicles E02F3/8866 takes precedence
• CPC Class Codes: E02F 9/207 of the type electric propulsion units, e.g. electric motors or generators
• CPC Class Codes: E02F 9/2091 Control of energy storage means for electrical energy, e.g. battery or capacitors energy recovery arrangements in hydraulic or pneumatic drives E02F9/2217
• CPC Class Codes: H02P 4/00 Arrangements specially adapted for regulating or controlling the speed or torque of electric motors that can be connected to two or more different electric power supplies vector control H02P21/00
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

The invention concerns a portable power supply system (30) intended to supply a remotely controlled, electrically driven work machine (1) with electrical power, where the work machine is of the type that demonstrates a propulsion means that includes continuous tracks (8b) and is equipped with a manoeuvrable arm (10) intended to carry a tool at its free end, and electric motor (19) that is connected to a hydraulic pump (20) and is intended to supply the operating means (8c, 10a) of the machine with a hydraulic medium, whereby the work machine is intended to be connected under normal operation to a primary source of power (30a) via an electrical cable (2′), which primary source of power includes a fixed alternating current electricity distribution grid at the location. In order to be able to supply the current that is required it comprises a DC energy-storage arrangement (29) that, including a secondary source of power (30b), can store energy and, when necessary, supply energy in electrical form;

a coupling arrangement (31, 33, 34, 34′) that makes it possible to choose between connecting the primary (30a) or the secondary (30b) source of power to the electric motor in order to drive the same.

Claims

1. A portable power supply system for an electrically driven work machine, comprising:

a propulsion means with continuous tracks with which the work machine can be driven,

a manoeuvrable arm adapted to support a tool at its free end,

an electric motor connected to a hydraulic pump and being adapted to supply the operating means of the work machine with a hydraulic medium,

a primary source of power to which the work machine is adapted to be connected during normal operation via an electrical cable and said primary source of power including a fixed alternating current electricity distribution grid at the location

a secondary source of power comprising a DC energy-storage arrangement with the ability to store and to supply electrical energy,

a rectifier for the conversion of AC alternating current from the fixed electricity distribution grid at the location to DC direct current for the energy-storage arrangement, and

a coupling arrangement arranged between the primary source of power, the secondary source of power and the electric motor such that when necessary, it allows the secondary source of power to be connected to the electric motor in order to drive the electrically driven work machine, temporarily,

wherein the coupling arrangement comprises a DC bus to which the rectifier is connected in order to supply DC direct current from the primary source of power to the DC bus, a control circuit which is connected to the DC bus and controls and monitors the levels of voltage that are supplied from the DC bus to the electric motor through continuously sending and receiving signals from the units that are connected to the DC bus.

2. The portable power supply system according to claim 1, wherein the electric motor is of three-phase alternating current type and the coupling arrangement comprises an inverted rectifier in order to reform the DC direct current that is supplied via the control circuit from the DC bus to AC alternating current for the said three-phase alternating current motor.

3. The portable power supply system according to claim 1, wherein the DC energy-storage arrangement is designed as a unit adapted to be supported as an integral part of the work machine.

4. The portable power supply system according to claim 1, wherein setting of the electrically driven work machine for operation by means of the secondary source of power can be carried out manually by an operator through the setting of a switch or button or automatically through the measurement and recording, by means of the control circuit, of the power surplus or power deficit that arises in the DC bus of the coupling arrangement.

5. The portable power supply system according to claim 2, wherein, when set into the operating condition in which reserve power is used that includes electrical energy from the secondary source of power, the system is arranged to supply a three-phase rated voltage at 400 V and a frequency of 50 Hz AC to the electric motor of the electrically driven work machine with the nominal power that is required to drive the electrically driven work machine according to the specified rating.

6. A portable power supply system according to claim 1, wherein the DC energy-storage arrangement with the integral secondary source of power comprises at least one of a battery or an electrical accumulator, a fuel cell, a genset or a supercondensor.

7. A portable power supply system according to claim 1, further comprising a control unit adapted to be carried by an operator who walks beside the electrically driven work machine and controls its various motions in a wireless manner through radio control or through a cable,

wherein the control unit can be switched between an operating condition for the addition of back-up power (secondary power), which operating condition in its active condition (On) is indicated to the operator with the aid of a symbol that is illuminated on a display or similar on the control unit, and in which operating condition the power supply system is arranged to supply a rated voltage to the electric motor of the work machine with the nominal power that is require in order to drive the same according to the specified rating.

10. The portable power supply system according to claim 1, wherein the fixed alternating current electricity distribution grid is rated a voltage of 400V and a frequency of 50 Hz.

8. An electrically driven work machine comprising:

a chassis with a propulsion means including continuous tracks,

a control unit adapted to be carried by an operator who walks beside the electrically driven work machine and controls its various motions in a wireless manner by radio control or through a cable,

a manoeuvrable arm adapted to support a tool at its free end,

a power supply system supported by the chassis comprising an electric motor is connected to a hydraulic pump and being adapted to supply the operating means of the work machine with a hydraulic medium,

a primary source of power to which the work machine is adapted to be connected during normal operation via an electrical cable and said primary source of power including a fixed alternating current electricity distribution grid at the location,

a secondary source of power comprising a DC energy-storage arrangement with the ability to store and to supply electrical energy,

a rectifier for the conversion of AC alternating current from the fixed electricity distribution grid at the location to DC direct current for the energy-storage arrangement,

a coupling arrangement arranged between the primary source of power, the secondary source of power and the electric motor such that when necessary, it allows the secondary source of power to be connected to the electric motor in order to drive the electrically driven work machine, temporarily,

wherein the coupling arrangement comprises a DC bus to which the rectifier is connected in order to supply DC direct current from the primary source of power to the DC bus, a control circuit which is connected to the DC bus and controls and monitors the levels of voltage that are supplied from the DC bus to the electric motor through continuously sending and receiving signals from the units that are connected to the DC bus, and in that the control unit can be switched between an operating condition for the addition of back-up power (secondary power), which operating condition in its active condition (On) is indicated to the operator with the aid of a symbol that is illuminated on a display or similar on the control unit, and in which operating condition the power supply system is arranged to supply a rated voltage to the electric motor of the work machine with the nominal power that is require in order to drive the same according to the specified rating.

9. The electrically driven work machine according to claim 8, wherein the electric motor is of three-phase alternating current type and the coupling arrangement comprises an inverted rectifier in order to reform the DC direct current that is supplied via the control circuit from the DC bus to AC alternating current for the said three-phase alternating current motor.

11. The portable power supply system according to claim 8, wherein the fixed alternating current electricity distribution grid is rated a voltage of 400V and a frequency of 50 Hz.