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 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 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 fail-back mode for 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 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. 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 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. 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 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. 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 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 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, 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 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.

> Generating limits on the inverter to 0 kW.

> Waiting until output power from inverter is 0 kW.

> Stopping the inverter.

> Executing "Charger to handover state contactor sequence".

> 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 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.

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 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.

In some examples, all operating modes are disabled when transitioning between modes. When the operating modes are disabled, the inverter may be configured for a 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. 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 1 ^st inverter mode 31a, and is reconfigurable for application as a motor inverter, e.g., during a 2 ^nd 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 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:

> Obtain input from the inverter by monitoring and generating limits on the inverter to O kW.

> Wait until output power from inverter is 0 kW.

> Stop inverter.

> Execute "Charger to handover state contactor sequence".

> 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:

> Obtain input from the inverter 31, confirming that a mode select of the inverter is in transition mode.

> 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:

> Obtain input from the inverter by monitoring and generating limits on the inverter to O kW. > Wait until output power from inverter is 0 kW.

> Stop inverter.

> Execute an "Energy Dump to handover state" contactor sequence

> 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. 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. 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. 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.