Note: Descriptions are shown in the official language in which they were submitted.
CA 03176121 2022-09-20
WO 2021/251864 PCT/SE2021/050464
Method and arrangements in an electric mining machine
TECHNICAL FIELD
The present disclosure relates to a system in an electric mining machine. In
particular, the
disclosure relates to a method and arrangements for inverter control in a
movable, electric
mining machine that is configured to perform a high power operation. The
disclosure also
relates to corresponding computer programs configured to cause execution of
the method
and a mining machine.
BACKGROUND
Day-to-day operations of mining typically involve excavation cycles of
transporting, drilling,
bolting, and blasting. Mining machines, e.g., loaders, haulers, dumpers, face
drill rigs,
production drill rigs, rock bolting rigs, cable bolting rigs, and concrete
spraying machines, are
configured for performing such operations. The mining machines require
considerable power
in the performing of the listed operations and during transportation to and
from an
operational site. In order to support the complex power demands of various
operations,
mining machines are configured to receive power from a grid during stationary
operation and
to perform other operations, e.g., transfer drives to/from an operational
position, using a
built-in rechargeable energy storage system, i.e., a battery. Thus, there is a
need to configure
mining machines to support various consumer connectivity modes of the mining
machine, the
consumer connectivity modes corresponding to AC- as well as DC-powered
operations.
Existing solutions for power sourcing of such consumer connectivity modes
require a plurality
of power converters, i.e., AC/DC converters or inverters, each power converter
configured to
provide power from respective power sources to a connected consumer. One
inverter may be
configured to adapt incoming power from an AC-grid to a grid-powered charging
operation,
while another inverter may be employed when performing a high power operation
driving
one or more electrically powered tools from a battery. Thus, existing
solutions require one
inverter configured for each mining machine operation. However, for improved
safety, there
may be a need to end a first operation before enabling a next operation.
Furthermore, with
the increasing complexity and multiplicity of various power sourced
operations, the multitude
CA 03176121 2022-09-20
WO 2021/251864 PCT/SE2021/050464
2
of inverters resulting from existing solutions will take up too much space in
limited space of a
mining machine. Consequently, there is a need for improvements in the power
sourcing of
electric mining machine and for improving inverter control in electric mining
machine.
SUMMARY
It is therefore an object of the present disclosure to provide a method, a
computer program
product, an inverter control arrangement, a power system, and a mining machine
that seeks
to mitigate, alleviate, or eliminate all or at least some of the above-
discussed drawbacks of
presently known solutions.
This and other objects are achieved by means of a method, a computer program
product, an
inverter control arrangement, a power system, and a mining machine as defined
in the
appended claims. The term exemplary is in the present context to be understood
as serving
as an instance, example or illustration.
According to a first aspect of the present disclosure, a method performed in
an inverter
control arrangement comprised in a power system of a movable, electric mining
machine is
provided. The electric mining machine is configured to perform a high power
operation driving
one or more electrically powered tools. The power system comprising a grid
connection, e.g.,
an AC grid connection, an optional battery, at least one electric traction
motor, at least one
electric drive motor configured to drive the one or more electrically powered
tools of the
mining machine, the inverter control arrangement, and an inverter configured
for operation
in one of a plurality of operating modes, each operating mode being associated
with a
parameter set in the inverter. The method comprises obtaining an input from
the inverter,
wherein the input comprises a first operating mode from the plurality of
operating modes of
the inverter and wherein the first operating mode is one of a traction
operation on battery
mode, a battery charging mode, an energy dump mode, a traction operation
without battery
mode, an on-board grid mode, and a high power drive operation on battery mode.
The
method further comprises selecting a second operating mode from the plurality
of operating
modes based on the obtained input, wherein the second operating mode is an
operating mode
different from the first operating mode and activating a transition mode in
the inverter prior
to activating a the second operating mode of the inverter. Activating the
second operating
CA 03176121 2022-09-20
WO 2021/251864 PCT/SE2021/050464
3
mode comprises operating the inverter with a parameter set associated with the
second
operating mode.
An advantage of the proposed method is that a single inverter is
reconfigurable for used in a
plurality of operating modes, supporting various consumer connectivity modes
of the mining
machine. Configuring a single inverter for operation in any mode among the
plurality of
operating modes, eliminates the requirement of multiple inverters thus
reducing cost and
space in the power system of the mining machine.
The proposed method allows an operator to select a desired operating mode of
the single
inverter. The operator may select any operating mode from the plurality of
operating modes,
e.g., through a graphical user interface provided to the operator. Further,
the proposed
method allows automatic mode selection in which an inverter control
arrangement of the
inverter selects the desired mode of operation of the inverter based on the
output power
and/or a priority level assigned to each operating mode of the inverter.
In some embodiments, the plurality of operating modes further comprises a
transition mode.
The transition mode may be activated in the inverter prior to activating the
second operating
mode. The transition mode is associated with one or more parameters for safe-
mode
operation of the inverter.
In some embodiments, the method further comprises selecting the first
operating mode of
the inverter or a further operating mode from the plurality of operating modes
and activating
the transition mode prior to re-activating the selected first operating mode
or activating the
selected further operating mode.
In some embodiments, selecting a second operating mode from the plurality of
operating
modes comprises selecting the transition mode when determining an anomaly in
the obtained
input from the inverter.
Thus, the introduction of the transition mode provides the advantage of
enabling safe
transitioning between two high-powered consumer modes, but also a safe fall-
back mode for
CA 03176121 2022-09-20
WO 2021/251864 PCT/SE2021/050464
4
the case that the inverter is mal-functioning. The safe-mode operation of the
inverter may be
a non-operative, connected state of the inverter.
In some embodiments, the second operating mode is one of a traction operation
on battery
mode, battery charging mode, an energy dump mode, a traction operation without
battery
mode, an on-board grid mode, and a high power drive operation on battery mode.
According to a second aspect of the present disclosure, there is provided a
computer program
product comprising a non-transitory computer readable medium having thereon a
computer
program comprising program instructions loadable into processing circuitry and
configured to
cause execution of the method according to the first aspect when the computer
program is
run by the processing circuitry.
According to a third aspect, an inverter control arrangement for a power
system of a movable,
electric mining machine is provided. The movable, electric mining machine is
configured to
perform a high power operation driving one or more electrically powered tools.
The power
system comprises a grid connection, e.g., an AC grid connection, an optional
battery, at least
one electric traction motor, at least one electric drive motor configured to
drive the one or
more electrically powered tools of the mining machine, the inverter control
arrangement, and
an inverter configured for operation in one of a plurality of operating modes,
each operating
mode being associated with a parameter set in the inverter. The inverter
control arrangement
further comprises processing circuitry configured to obtain an input from the
inverter,
wherein the input comprises a first operating mode from the plurality of
operating modes of
the inverter and wherein the first operating mode is one of a traction
operation on battery
mode, battery charging mode, an energy dump mode, a traction operation without
battery
mode, an on-board grid mode, and a high power drive operation on battery mode.
The
processing circuitry is further configured to select a second operating mode
from the plurality
of operating modes based on the obtained input, wherein the second operating
mode is an
operating mode different from the first operating mode. The processing
circuitry is further
configured to activate a transition mode in the inverter prior to activating
the second
operating mode and to activate the second operating mode of the inverter.
Activating the
CA 03176121 2022-09-20
WO 2021/251864 PCT/SE2021/050464
second operating mode comprises operating the inverter with a parameter set
associated with
the second operating mode.
According to a fourth aspect, a power system comprising the inverter control
arrangement of
the third aspect is provided. The power system is comprised in a movable,
electric mining
machine configured to perform a high power operation driving one or more
electrically
powered tools. The power system comprises a grid connection, e.g., an AC grid
connection,
an optional battery, at least one electric traction motor, at least one
electric drive motor
configured to drive the one or more electrically powered tools of the mining
machine, an
inverter control arrangement according to the third aspect, and an inverter
configured for
operation in one of a plurality of operating modes, each operating mode being
associated with
a parameter set in the inverter.
In some embodiments, the power system further comprises a battery charger
configured to
charge a battery when receiving power over the grid connection.
According to a fifth aspect of the present disclosure, a mining machine
configured to perform
a high power operation driving one or more electrically powered tools is
provided. The mining
machine comprises a power system according to the fourth aspect.
In some embodiments, the high power operation is an at least partly
stationary, high power
operation, e.g., a drilling or a bolting operation and wherein the mining
machine is a drill rig
or a bolting rig. Drill rigs, such as face drill rigs and production drill
rigs, require particularly
high peak powers during high power operation of drilling, and therefore
benefit particularly
well from the disclosed power system and associated method.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing will be apparent from the following more particular description
of the example
embodiments, as illustrated in the accompanying drawings in which like
reference characters
refer to the same parts throughout the different views. The drawings are not
necessarily to
scale, emphasis instead being placed upon illustrating the example
embodiments.
CA 03176121 2022-09-20
WO 2021/251864 PCT/SE2021/050464
6
Figure 1 illustrates a mining machine comprising a power system, and an
inverter control
arrangement according to the present disclosure
Figure 2 provides a flowchart representation of example method steps
performed in an
inverter control arrangement;
Figure 3 discloses an example block diagram of a power system comprising an
inverter
control arrangement; and
Figure 4 discloses an example block diagram of an inverter control
arrangement.
DETAILED DESCRIPTION
Aspects of the present disclosure will be described more fully hereinafter
with reference to
the accompanying drawings. The apparatus and method disclosed herein can,
however, be
realized in many different forms and should not be construed as being limited
to the aspects
set forth herein. Like numbers in the drawings refer to like elements
throughout.
The terminology used herein is for the purpose of describing particular
aspects of the
disclosure only, and is not intended to limit the invention. It should be
emphasized that the
term "comprises/comprising" when used in this specification is taken to
specify the presence
of stated features, integers, steps, or components, but does not preclude the
presence or
addition of one or more other features, integers, steps, components, or groups
thereof. As
used herein, the singular forms "a", "an" and "the" are intended to include
the plural forms as
well, unless the context clearly indicates otherwise.
Embodiments of the present disclosure will be described and exemplified more
fully
hereinafter with reference to the accompanying drawings. The solutions
disclosed herein can,
however, be realized in many different forms and should not be construed as
being limited to
the embodiments set forth herein.
In some implementations and according to some aspects of the disclosure, the
functions or
steps noted in the blocks can occur out of the order noted in the operational
illustrations. For
example, two blocks shown in succession can in fact be executed substantially
concurrently
or the blocks can sometimes be executed in the reverse order, depending upon
the
CA 03176121 2022-09-20
WO 2021/251864 PCT/SE2021/050464
7
functionality/acts involved. Also, the functions or steps noted in the blocks
can according to
some aspects of the disclosure be executed continuously in a loop.
It will be appreciated that when the present disclosure is described in terms
of a method, it
may also be embodied in one or more processors and one or more memories
coupled to the
one or more processors, wherein the one or more memories store one or more
programs that
perform the steps, services and functions disclosed herein when executed by
the one or more
processors.
In the following description of exemplary embodiments, the same reference
numerals denote
the same or similar components.
Figure 1 illustrates a mining machine 10 comprising a one or more electrically
powered tools
11, and a power system 12 according to the present disclosure. The power
system 12
comprises a grid connection, e.g., an AC grid connection 13, through which the
power system
is configured to receive electrical power from a grid, e.g., a local AC grid
to power the mining
machine. Consequently, the mining machine is configured to perform a high
power operation,
e.g., driving one or more electrically powered tools when connected to the AC
grid. The power
system is configured to provide electrical power to the one or more
electrically powered tools
11 and to provide power to an optional battery. The battery may provide power
to a traction
system of the mining machine. Thus, the power system is configured to support
one or more
consumers, i.e., driving the one or more electrically powered tools and
providing power to an
electrically powered traction system. In order to support the complex power
demands of
various operations, the mining machine is configured to receive power from a
grid during
stationary operation and to perform other operations, e.g., transfer drives
to/from an
operational position, using a built-in rechargeable energy storage system,
i.e., a battery. Thus,
there is a need to configure mining machines to support various consumer
connectivity modes
of the mining machine, the consumer connectivity modes corresponding to AC- as
well as DC-
powered operations.
The battery is a rechargeable battery comprising a plurality of battery cells
organized as one
or more battery sub packs or a plurality of battery cells organized in a
single battery pack.
CA 03176121 2022-09-20
WO 2021/251864 PCT/SE2021/050464
8
The disclosed power system 12 comprises an grid connection 13, a battery 15,
at least one
electric traction motor 16, at least one electric drive motor 17 configured to
drive the one or
more electrically powered tools of the mining machine, an inverter control
arrangement 13,
and an inverter 14 configured for operation in a plurality of operating modes;
each operating
mode being associated with a parameter set in the inverter. As previously
explained, existing
solutions for power sourcing of mining machine consumers required a plurality
of power
converters, i.e., AC/DC converters or inverters; each power converter being
configured to
provide power from respective power sources to a connected consumer.
In the present disclosure, the term inverter is used to represent a current
transforming device
capable of AC/DC-conversion, DC/AC-conversion, AC/AC-transforming and DC/DC
transforming.
In the present disclosure, the term battery is used to represent a
rechargeable energy storage
device comprised in a power system of a mining machine. The term battery
should be
interpreted to represent any of a rechargeable energy storage, e.g., a
battery, a super
capacitor, a rechargeable fuel cell and a flywheel. It will also be understood
that the term
battery may reflect a plurality of rechargeable batteries co-located within a
mining machine
or a single battery unit comprising a plurality of battery cells, wherein one
or more battery
cells of the plurality of battery cells may define a rechargeable battery. In
some examples, the
batteries are Lithium ion batteries. Each battery is configured for use in a
respective mining
machine. Each battery is rechargeable and may comprise a plurality of battery
cells organized
as one or more battery sub packs or a plurality of battery cells organized in
a single battery
pack. According to the present disclosure, the inverter control arrangement 13
comprises
processing circuitry configured to control operation of the inverter. More
specifically, the
processing circuitry is configured to obtain an input from the inverter 14,
wherein the input
comprises a first operating mode from a plurality of operating modes of the
inverter, e.g.,
consumer connectivity modes, and wherein the first operating mode is one of a
traction
operation on battery mode, battery charging mode, an energy dump mode, a
traction
operation without battery mode, an on-board grid mode, and a high power drive
operation
on battery mode. The processing circuitry is further configured to select a
second operating
CA 03176121 2022-09-20
WO 2021/251864 PCT/SE2021/050464
9
mode from the plurality of operating modes based on the obtained input,
wherein the second
operating mode is an operating mode different from the first operating mode;
and to activate
the second operating mode of the inverter, wherein activating the second
operating mode
comprises operating the inverter with a parameter set, e.g., preconfigured
parameter set,
associated with the second operating mode. In the context of the present
disclosure, the
parameter set may comprise parameter settings for contactor sequencing,
activating or
deactivating contactors that in turn enable or disable electrical connections
between the
optional battery 15, a battery charger, the traction motor, the grid
connection, and/or the one
or more electrically powered tools of the mining machine.
Thus, a single inverter is reconfigurable, by means of the inverter control
arrangement, to be
used in at least one of a traction operation on battery mode, battery charging
mode, an energy
dump mode, a traction operation without battery mode, an on-board grid mode,
and a high
power drive operation on battery mode. Furthermore, using the same single
inverter also
when transitioning into a different operating mode, i.e., another mode of the
traction
operation on battery mode, battery charging mode, energy dump mode, traction
operation
without battery mode, an on-board grid mode, and high power drive operation on
battery
mode, or a further mode such as a transition mode, provides for improved
safety in the
operation of the mining machine when having a high power grid connection. An
additional
benefit of the ability of configuring a single inverter for operation in any
mode among the
plurality of operating modes, is that this eliminates the requirement of
multiple inverters,
associated components, and wiring; thus reducing cost and space in the power
system of the
mining machine.
In some examples, the electrically powered tools are actuated by means of a
hydraulic drive
system, e.g., by means of electro-hydraulic actuators. In other examples, the
electrically
powered tools are directly driven from the electric drive motor, e.g.,
operating an electric
percussion tool. In some examples, the electrically powered tools one or more
buckets, lifting
scoops, truck beds, or any other electrically powered tools or devices on a
loader, hauler, or
dumper. In other examples, the electrically powered tools comprise percussive
tools, such as
a bolting rig or a drill rig, and hydraulic attachment tools.
CA 03176121 2022-09-20
WO 2021/251864 PCT/SE2021/050464
In some examples, the power system comprises an interface to a machine control
unit of the
mining machine. Thus, control signals from the machine control unit of the
mining machine
may be used for the selection of an inverter operating mode in the inverter
control unit.
Mining machines such as loaders, haulers, dumpers, and concrete spraying
machines may
experience the need to perform a high power operation, e.g., an at least
partly stationary,
high power operation, and thus benefit from the disclosed power system.
Bolting rigs, e.g.,
rock bolting rigs and cable bolting rigs, and drill rigs, e.g. face drill rigs
and production drill rigs,
mainly perform stationary high power operations and are thus particularly
suitable for having
a power system as described above and below. Thus, according to some aspects,
the mining
machine is a bolting rig or a drill rig.
The plurality of operating modes of the inverter may be supported by
dynamically controlled
electrical connections between the grid connection, a battery charger, an
optional battery,
the at least one traction motor and the at least one electric motor powering
the electrically
powered tools of the mining machine. In some examples, the at least one
electric traction motor
is an AC motor or a DC motor and the at least one electric drive motor is an
AC motor. In some
examples an auxiliary motor (AUX motor), such as a low power AC-motor, is
comprised in the
power system; the AUX motor being configured to pressurize and create flow in
steering,
braking, cooling systems and drive hydraulic pumps, coolant circulation pumps,
air conditioner
compressors etc.
The battery charging mode may be powered by enabling power supply from the
grid, e.g., AC
grid, to the battery charger. Consequently, the disclosed power system may
comprise a battery
charger configured to charge a battery when receiving power over the grid
connection. In other
scenarios, the traction motor may be powered by enabling power supply from the
AC grid, by
means of the inverter, during a traction operation without battery mode.
Similarly, power
supply from the battery to the electrically powered tools may be enabled by
deactivating the
grid connection to the electrically powered tools and activating an electrical
connection
whereby the inverter is capable of providing AC power to the electrically
powered tools. Thus,
in addition to supporting the various operating modes, the power system,
comprising the
CA 03176121 2022-09-20
WO 2021/251864 PCT/SE2021/050464
11
inverter, provides a power safety buffer between the electrical power grid and
the one or
more consumers, i.e., the battery charger, and the one or more electrically
powered tools.
Turning to Figure 2, a flow chart representation of example method steps
performed in a
inverter control arrangement in an electric mining machine is disclosed, e.g.,
in the power
system as included in the mining machine of Figure 1. The example method steps
may be
performed by an inverter control arrangement comprised in the power system.
The mining
machine is configured to perform a high power operation, e.g., an at least
partly stationary
high power operation, driving one or more electrically powered tools. The
power system
comprises a grid connection, e.g., an AC grid connection, an optional battery,
at least one
electric traction motor, at least one electric drive motor configured to drive
the one or more
electrically powered tools of the mining machine, an inverter control
arrangement, and an
inverter configured for operation in one of a plurality of operating modes. A
plurality of
parameter sets corresponding to respective operating modes may have been
defined in the
inverter and the inverter arrangement is configured to operate in any of these
parameter sets
in response to receiving information regarding the parameters or parameter
set, e.g.,
switching between preconfigured parameter sets, when receiving information
identifying an
operating mode. Thus, each inverter operating mode may be associated with a
parameter set
in the inverter and upon receiving information regarding an operating mode to
be applied, the
inverter may activate the parameter set. In the context of the present
disclosure, the
parameter set may comprise preconfigured parameter settings for contactor
sequencing,
activating or deactivating contactors that in turn enable or disable
electrical connections
between a battery, the battery charger, the traction motor, the grid
connection, and/or the
one or more electrically powered tools of the mining machine. Furthermore, the
parameter
set may comprise timing parameters that determine a time interval providing a
mandated
delay when initiating the mode switch.
When initially defining the operating mode, activation of an operating mode
may comprises
the operation of setting the parameters in the inverter, e.g., by setting
parameters in the
inverter control arrangement and uploading the resulting parameter settings to
the inverter
to configure the inverter for operating in a plurality of predefined modes. In
the following
CA 03176121 2022-09-20
WO 2021/251864 PCT/SE2021/050464
12
instances of reactivating an operating mode after having a previous exit or
transitioning from
said operating mode, the parameter set will be accessible without the need for
defining
specific parameters. In some examples, implementing an operating mode may also
involve
changing one or more parameters within a parameter set. Thus, while the
inverter is
configured to store parameter sets corresponding to respective operating
modes, it is also
possible to implement changes within the parameter set, e.g., when changing or
transitioning
between operating modes.
The disclosed method, performed in an inverter control arrangement of the
power system, is
a computer-implemented method that comprises the steps of obtaining S21 an
input from the
inverter, wherein the input comprises a first operating mode from the
plurality of operating
modes of the inverter and wherein the first operating mode is one of a
traction operation on
battery mode, a battery charging mode, an energy dump mode, a traction
operation without
battery mode, an on-board grid mode, and a high power drive operation on
battery mode.
The respective modes will be further explained and exemplified below.
Traction operation on battery mode: This mode represents a tramming mode for
the mining
machine, e.g., performing a battery powered transport operation.
Battery charging mode: This mode provides power to a battery charger, e.g., at
the same time
as powering the one or more electrically powered tools. The battery charging
mode enables
supply of DC-power for charging a battery, the DC-power being converted from
AC-power
received through the AC-grid connection.
Energy dump mode: Configuration wherein the inverter is used as a motor
inverter to dump
power. In this mode, a portion of power from is dumped to remove the excess
power, e.g.,
during a downhill transfer operation of the mining machine or to dump energy
from a battery
or battery subpack prior to a replacement operation. During the energy dump
operation, mock
operations may be performed using one or more consumers in the mining machine.
Operation without battery mode: Configuration to operate mining machine
without battery
using grid power instead. This mode enables operation of a consumer without
the battery,
CA 03176121 2022-09-20
WO 2021/251864 PCT/SE2021/050464
13
e.g., converting power from the AC-grid to operate the traction motor during a
transfer
operation of the mining machine.
On-board grid mode: Configuration wherein the inverter may be used as a grid
inverter to
power tools from either battery power or grid power, or to provide battery
power to the grid.
Dependent on power load and system set up, the mode may allow connecting one
motor after
another, when connecting a plurality of motors to the grid. In this mode, one
or more
electrically powered tools are driven using either battery power, grid power,
or seamlessly
switched between battery and grid power. One or more high power rotating
motors may
initially be powered using battery power, whereas frequency, phase and
amplitude are
synchronized with the grid. Grid power may then be connected and battery power
disconnected for further continued operation of the motors using only grid
power. If the grid
power for any reason cannot provide the power needed, the inverter control
arrangement
may enable simultaneous battery power provisioning.
High power drive operation on battery mode: The configuration may be an
extension of the
energy dump mode; including hydraulic pumps and cooling for performing the
high power
operation on battery. In this mode, one or more electrically powered tools are
driven using
battery power. Examples include drilling or bolting on battery power, e.g.,
driving percussive
tools on battery power. Other examples comprising loading, hauling or dumping
on battery
power.
A second operating mode is selected S23 from the plurality of operating modes,
e.g., the
above disclosed modes, based on the obtained input, wherein the second
operating mode is
an operating mode different from the first operating mode. The method further
comprises
activating S24 a transition mode in the inverter and subsequently activating
S25 the second
operating mode of the inverter. Activating the second operating mode comprises
operating
the inverter with a parameter set, e.g., a preconfigured parameter set,
associated with the
second operating mode.
In some examples, an operator can select the second operating mode, e.g., any
one of the
traction operation on battery mode, the battery charging mode, the energy dump
mode, the
CA 03176121 2022-09-20
WO 2021/251864 PCT/SE2021/050464
14
operation without battery mode and the drilling on battery mode, but automatic
mode
selection may also be enabled. Automatic mode selection may be based on
assigned mode
priority levels as will be further discussed below. In some examples, manual
mode selection
may override automatic mode selection.
In some examples, the plurality of operating modes further comprises a
transition mode,
wherein selecting a second operating mode may comprise selecting the
transition mode. The
transition mode may also be an intermediary, safety mode that is automatically
activated prior
to activating a selected second operating mode, i.e., to bridge the
transitioning from the first
operating mode to the selected second operating mode. In some instances, when
an operator
manually activates the second operating mode, an automated activation of the
transition
mode will precede the manually induced activation of the second operating
mode. In some
examples, the transition mode is associated with a parameter set for a non-
operative,
connected state of the inverter, i.e., associated with one or more parameters
for safe-mode
operation of the inverter. Thus, the introduction of such a transitioning mode
may provide for
increased safety when operating the mining machine.
Thus, the inverter 108 may be configured to operate in the transition mode,
for example, a
few milliseconds prior to activating the second operating mode. The following
sequence of
operations may be performed for activating the transition mode from the
battery charging
mode.
D Generating limits on the inverter to 0 kW.
D Waiting until output power from inverter is 0 kW.
D Stopping the inverter.
D Executing "Charger to handover state contactor sequence".
D Activating the transition mode.
In some examples, the obtained input from the inverter comprises information
reflecting a
first operating mode of the inverter. The first operating mode may be any of a
traction
operation on battery mode, the battery charging mode, an operation without
battery mode,
a high power operation on battery mode, an on-board grid mode, and an energy
dump mode.
In some examples, the battery charging mode is a default operating mode of the
inverter; the
CA 03176121 2022-09-20
WO 2021/251864 PCT/SE2021/050464
default operating mode being the first operating mode. As mentioned, the
inverter may be
configured to store a plurality of predefined parameter sets corresponding to
respective
operating modes of the inverter. Therefore, each operating mode may be
associated with a
predefined parameter set. For example, the default operating mode, e.g.,
battery charging
mode, is associated with a default parameter set. The default parameter set
may comprise a
minimum of predetermined settings for voltages and time intervals. For example
a
predetermined voltage setting in the battery charging mode is a charging
voltage of 23 V, a
lowest voltage setting may be 0 V, a resolution set to 0.1 V and a highest
allowable voltage
setting 30V.
A default parameter setting may include the voltage settings. Example
parameter settings
including predetermined values for voltage and/or time intervals for each
operating mode
may be used as shown in the below table.
Lowest value, resolution, Predetermined
Mode Unit
highest value value
Battery charging 0, 0.1, 30 23 V
Energy Dump 0, 0.1, 30 22 V
Operation without battery 0, 1, 60 10 s
High power drive
0,1,60 10 s
operation on battery
In some examples, the method further comprises selecting the first operating
mode of the
inverter, i.e., reselecting the first operating mode, or selecting a further
operating mode from
the plurality of operating modes and activating S24 the transition mode prior
to re-activating
the selected first operating mode or activating the selected further operating
mode.
In some examples, an operating mode of the inverter may be selected and/or
activated based
on a priority level assigned to each of the plurality of operating modes. The
priority level
enables the power system to prioritize and control operating mode
transitioning. The control
system may be configured to automatically select and/or activate an operating
mode, e.g., the
second operating mode, based on the assigned priority level. For example, the
battery charger
mode may be assigned with a first priority level, the energy dump mode may be
assigned with
a second priority level, operation without battery may be assigned with a
third priority level
CA 03176121 2022-09-20
WO 2021/251864 PCT/SE2021/050464
16
and high power drive operation on battery mode may be assigned with a fourth
priority level,
etc. When the inverter 108 is operating in the first operating mode e.g., the
battery charger
mode the power system may be allowed to automatically activate an operating
mode of a
second priority level in response to receiving a request to deactivate the
battery charging
mode.
In some examples, the operating modes of the inverter may be prioritized
depending on
prevailing conditions for the mining machine. For example, during a start
operation of the
mining machine, the power system may activate a default mode for the inverter.
In some examples, an operator or a user can select and/or activate the second
operating
mode. For example, a machine control system of the mining machine may comprise
a
Graphical User Interface (GUI) to receive user input from an operator
selecting and/or
activating the second operating mode. When an operating mode is enabled
through manual
selection through the GUI, then the remaining modes may be disabled. For
example, when
the operator enables a battery charging mode using the GUI, then the other
modes such as
energy dump mode, operation without battery mode and drilling on battery mode
may be
disabled.
Mode Enabled Disabled
Battery Charging X
Energy Dump X
Operation without battery X
High power operation on battery X
In some examples, all operating modes are disabled when transitioning between
modes.
When the operating modes are disabled, the inverter may be configured fora
transition mode,
e.g., an intermediary, safety mode. Disabling a currently active mode, the
machine control
system may be configured to select a default mode, e.g., the battery charging
mode. When
the default mode is disabled, the inverter control arrangement may be
configured to reset the
inverter to the transition mode, i.e., to a safety mode with nonce-value
parameter settings.
CA 03176121 2022-09-20
WO 2021/251864 PCT/SE2021/050464
17
Turning to Figure 3, an example implementation of an inverter control
arrangement 30 and
associated mode select 30a functionality is disclosed. In the example
implementation, the
inverter is connected, e.g., by means of contactors, to the grid through a
grid connect module
32, and to one or more battery packs through a battery connect module 33. The
contactors
34 may also be provided to enable the interconnection of the inverter 31 and a
charger
module 35 and motor module(s) 36. In the disclosed example, the inverter 31
may be used in
an application as charger inverter, e.g., during a 1st inverter mode 31a, and
is reconfigurable
for application as a motor inverter, e.g., during a 2nd inverter mode 31b.
Thus, the disclosed
inverter 31 is reconfigurable to operate in a plurality of operating modes
31a, 31b,.., 31n to
enable charging, energy dump, drilling on battery power and operation without
battery. The
purpose of mode select is to prioritize, select and enable safe transition
between modes of
operation. While the mode select may be a fully automated procedure performed
by the
inverter control arrangement, the selection procedure may also involve
operator control ¨ at
least in part. In the example implementation, the operating modes comprise a
traction
operation on battery mode, a battery charging mode, an energy dump mode, an
operation
without battery mode, an on-board grid mode, and a high power operation on
battery mode.
A transition mode is also foreseen, representing an operating mode when none
of the above
mentioned operating modes have been selected and/or activated.
Use case 1¨ Automatic mode selecting of default battery charging mode
When connecting the mining machine to the AC-grid, the inverter control
arrangement may
be configured to automatically select a battery charging mode. Selecting the
charger mode
comprises changing inverter settings according to a predetermined parameter
set, e.g., via a
direct drive parameter access. The inverter control arrangement may verify
that the
parameter set selection has been completed, i.e., that the parameters
corresponding to the
selected parameter set has been introduced for the further inverter operation;
when the
verification has been concluded the inverter is now configured to operate in
the battery
charger mode. However, if any of the conditions required for activating the
battery charging
mode is incomplete, a currently active mode shall be maintained ¨ preferably
keeping the
inverter in a transition mode. Following selection of the battery charging
mode, a set of
CA 03176121 2022-09-20
WO 2021/251864 PCT/SE2021/050464
18
contactors 34 may be activated to enable the on-board battery charger function
and a
calculated charging power set-point may be passed through to the inverter.
When the inverter is operating in the battery charging mode, i.e.,
representing a first
operating mode and there is a need to activate an energy dump mode as a second
operating
mode of the inverter 31, the transition mode may be activated as an
intermediary safe mode.
The following sequence of operations may be performed for activating the
transition mode
from the battery charging mode:
D Obtain input from the inverter by monitoring and generating limits on the
inverter to
0 kW.
D Wait until output power from inverter is 0 kW.
D Stop inverter.
D Execute "Charger to handover state contactor sequence".
D Activate transition mode.
In another example when mode select 30a has been activated in the inverter
control
arrangement 30 and the inverter 31 is transition into an energy dump mode from
the
transition mode the following sequence of operations may be performed by the
inverter
control arrangement 30:
D Obtain input from the inverter 31, confirming that a mode select of the
inverter is in
transition mode.
D Select, load and verify Energy Dump user parameter set.
Thus, the inverter control arrangement 30 activates energy dump mode in the
inverter 31
from the transition mode by performing the steps as mentioned above. In case,
when the
inverter 31 is operating in the energy dump mode and transitioning to the
battery charging
mode, the transition mode may be activated as an intermediary mode. The
following
sequence of operations may be performed by the inverter control arrangement
for activating
the transition mode from the energy dump mode:
D Obtain input from the inverter by monitoring and generating limits on the
inverter to
0 kW.
CA 03176121 2022-09-20
WO 2021/251864 PCT/SE2021/050464
19
D Wait until output power from inverter is 0 kW.
D Stop inverter.
D Execute an "Energy Dump to handover state" contactor sequence
D Activate transition mode
Figure 4 discloses a block diagram illustrating an example inverter control
arrangement 40 for
controlling inverter mode selection and activation in a power system of a
mining machine. The
inverter control unit comprising processing circuitry 41 configured to obtain
an input from the
inverter, wherein the input comprises a first operating mode from the
plurality of operating
modes of the inverter and wherein the first operating mode is one of a
traction operation on
battery mode, a battery charging mode, an energy dump mode, a traction
operation without
battery mode, and a high power drive operation on battery mode. The processing
circuitry is
further configured to select a second operating mode from the plurality of
operating modes
based on the obtained input, wherein the second operating mode is an operating
mode
different from the first operating mode; and to activate the second operating
mode of the
inverter, wherein activating the second operating mode comprises operating the
inverter with
a parameter set associated with the second operating mode.
Figure 4 also illustrates an example computer program product 42 having
thereon a computer
program comprising instructions. The computer program product comprises a
computer
readable medium such as, for example a universal serial bus (USB) memory, a
plug-in card, an
embedded drive or a read only memory (ROM). The computer readable medium has
stored
thereon a computer program comprising program instructions. The computer
program is
loadable into a processing circuitry 41 comprised in the inverter control unit
40. When loaded
into the processing circuitry 41, the computer program may be stored in a
memory 41b
associated with or comprised in the processing circuitry and executed by the
processor 41a.
According to some embodiments, the computer program may, when loaded into and
run by
the processing circuitry, cause execution of method steps according to, for
example, the
method illustrated in Figure 3 or otherwise described herein.
CA 03176121 2022-09-20
WO 2021/251864 PCT/SE2021/050464
Thus, the computer program is loadable into data processing circuitry, e.g.,
into the processing
circuitry 41 of Figure 4, and is configured to cause execution of embodiments
for inverter
control in a power system of a mining machine.
The description of the example embodiments provided herein have been presented
for
purposes of illustration. The description is not intended to be exhaustive or
to limit example
embodiments to the precise form disclosed; modifications and variations are
possible in light
of the above teachings or may be acquired from practice of various
alternatives to the
provided embodiments. The examples discussed herein were chosen and described
in order
to explain the principles and the nature of various example embodiments and
its practical
application to enable one skilled in the art to utilize the example
embodiments in various
manners and with various modifications as are suited to the particular use
contemplated. The
features of the embodiments described herein may be combined in all possible
combinations
of source nodes, target nodes, corresponding methods, and computer program
products. It
should be appreciated that the example embodiments presented herein may be
practiced in
combination with each other.
The described embodiments and their equivalents may be realized in software or
hardware
or a combination thereof. The embodiments may be performed by general purpose
circuitry.
Examples of general purpose circuitry include digital signal processors (DSP),
central
processing units (CPU), co-processor units, field programmable gate arrays
(FPGA) and other
programmable hardware. Alternatively or additionally, the embodiments may be
performed
by specialized circuitry, such as application specific integrated circuits
(ASIC). The general
purpose circuitry and/or the specialized circuitry may, for example, be
associated with or
comprised in an apparatus such as a wireless communication device or a network
node.
Embodiments may appear within an electronic apparatus comprising arrangements,
circuitry,
and/or logic according to any of the embodiments described herein.
Alternatively or
additionally, an electronic apparatus may be configured to perform methods
according to any
of the embodiments described herein.
CA 03176121 2022-09-20
WO 2021/251864 PCT/SE2021/050464
21
Generally, all terms used herein are to be interpreted according to their
ordinary meaning in
the relevant technical field, unless a different meaning is clearly given
and/or is implied from
the context in which it is used.
Reference has been made herein to various embodiments. However, a person
skilled in the
art would recognize numerous variations to the described embodiments that
would still fall
within the scope of the claims.
For example, the method embodiments described herein discloses example methods
through
steps being performed in a certain order. However, it is recognized that these
sequences of
events may take place in another order without departing from the scope of the
claims.
Furthermore, some method steps may be performed in parallel even though they
have been
described as being performed in sequence. Thus, the steps of any methods
disclosed herein
do not have to be performed in the exact order disclosed, unless a step is
explicitly described
as following or preceding another step and/or where it is implicit that a step
must follow or
precede another step.
In the same manner, it should be noted that in the description of embodiments,
the partition
of functional blocks into particular units is by no means intended as
limiting. Contrarily, these
partitions are merely examples. Functional blocks described herein as one unit
may be split
into two or more units. Furthermore, functional blocks described herein as
being
implemented as two or more units may be merged into fewer (e.g. a single)
unit.
Any feature of any of the embodiments disclosed herein may be applied to any
other
embodiment, wherever suitable. Likewise, any advantage of any of the
embodiments may
apply to any other embodiments, and vice versa.
In the drawings and specification, there have been disclosed exemplary aspects
of the
disclosure. However, many variations and modifications can be made to these
aspects without
substantially departing from the principles of the present disclosure. Thus,
the disclosure
should be regarded as illustrative rather than restrictive, and not as being
limited to the
particular aspects discussed above. Accordingly, although specific terms are
employed, they
are used in a generic and descriptive sense only and not for purposes of
limitation.
CA 03176121 2022-09-20
WO 2021/251864 PCT/SE2021/050464
22
Hence, it should be understood that the details of the described embodiments
are merely
examples brought forward for illustrative purposes, and that all variations
that fall within the
scope of the claims are intended to be embraced therein.
