A power control arrangement

Abstract

A power control arrangement (100) for a mining / construction machine comprises: a power bus (110) connectable to a power grid (200), receiving an input power (IP) from the power grid; a first battery (120) and at least one second battery (130) receiving / supplying power from / to the power bus; and at least one load (310) receiving an output power (OP) from the power bus; wherein the power control arrangement adapts a power limit margin of the power grid based on a power supply mode of the power bus, wherein the power supply mode comprises that: 1) only one of the power grid, the first battery, or the second battery supplies power to the power bus; or 2) a combination of at least two of the power grid, the first battery and the second battery supplies power to the power bus.

Description

[0001] A POWER CONTROL ARRANGEMENT

[0002] Technical Field

[0003] The disclosure relates to a power control arrangement for a mining / construction machine. Furthermore, the disclosure also relates to a corresponding method and a mining / construction machine comprising such a power distribution arrangement.

[0004] Background

[0005] Electrified mining / construction machines and vehicles provide an opportunity to reduce the environmental footprint and create a healthier work environment in mining / construction environments.

[0006] The electrified mining / construction machine is driven by one or more electric motors which in turn may be powered by an electric grid system and / or an on-board electrical storage system (ESS) comprising e.g., battery packs etc. Compared to diesel machines, the electrified mining / construction machines are emission free and can hence bring considerable savings, especially for ventilation and cooling in mining / construction environments.

[0007] However, the electrified mining / construction machines need electrical power for their functioning and operation. That is, for powering electrical motors, batteries, etc. of the electrified mining / construction machines. In this respect, a power control arrangement may be provided for this purpose.

[0008] The power control arrangement is arranged to provide power from a plurality of power sources to loads via a DC bus in an efficient way. Examples of power sources supplying power to the DC bus are a power grid and batteries.

[0009] Summary

[0010] An objective of embodiments of the disclosure is to provide a solution which mitigates or solves the drawbacks of conventional solutions. Another objective of embodiments of the disclosure is to provide a power control arrangement operating more efficiently compared to conventional power control arrangements.

[0011] According to a first aspect of the disclosure, the above mentioned and other objectives are achieved with a power control arrangement for a mining / construction machine, the power control arrangement comprising: a power bus connected to a power grid and configured to receive an input power from the power grid; a first battery connected to the power bus and configured to receive a power from the power bus or supply a first battery power to the power bus; at least one second battery connected to the power bus and configured to receive a power from the power bus or supply a second battery power to the power bus; and at least one load connected to the power bus and configured to receive an output power from the power bus; wherein the power control arrangement is configured to: adapt a power limit margin of the power grid based on a power supply mode of the power bus, wherein the power supply mode comprises that: only the input power from the power grid, or only the first battery power, or only the second battery power is supplied on the power bus; or a combination of the input power from the power grid and / or the first battery power and / or the second battery power is supplied on the power bus.

[0012] Thus, it is understood that the power supply mode of the power bus involves any of: only one of the power grid, the first battery, or the at least one second battery supplying power to the power bus; or any combinations of the power grid, the first battery, and the at least one second battery supplying power to the power bus.

[0013] An advantage of the power control arrangement according to the first aspects is that the power limit margin is adapted to the power supply mode of the power bus which means that a maximum allowed power can be supplied to the power bus and therefore to the load while maintaining a reliable and safe operation by having enough power limit margin to e.g., handle contingencies. In an implementation form of a power control arrangement according to the first aspect, the power supply mode is a scheduled power supply mode of the power bus.

[0014] An advantage with this implementation form is that power control arrangement can provide maximum power while ensuring robust operation during change of power sources adapted to the scheduled power supply mode.

[0015] In an implementation form of a power control arrangement according to the first aspect, the power limit margin is based on a difference between an upper power limit of the power grid and maximum allowed input power from the power grid.

[0016] The expression “upper power limit of the power grid” herein used may also be denoted a grid power limit.

[0017] In an implementation form of a power control arrangement according to the first aspect, the power control arrangement is configured to: adapt the power limit margin further based on a maximum power transfer capability of a power connection line interconnecting the power grid and the load.

[0018] An advantage with this implementation form is that maximum power can be supplied to the load while also considering the power transfer capability of the power connection line. Thereby, safe operation is ensured with maximum power transfer without power transfer failure e.g., due to power overload.

[0019] In an implementation form of a power control arrangement according to the first aspect, the adapting of the power limit margin of the power grid comprises: increasing or decreasing the power limit margin.

[0020] In an implementation form of a power control arrangement according to the first aspect, the power control arrangement is configured to: charge or discharge the first battery and / or the second battery based on a schedule of the load. The schedule of the load may be a power consumption schedule of the load depending on its work cycle.

[0021] An advantage with this implementation form is that the batterie(s) connected to the power bus can be used efficiently and supply power to meet the load demand.

[0022] In an implementation form of a power control arrangement according to the first aspect, the power control arrangement is configured to: charge or discharge the first battery and / or the second battery based on the schedule of the load and a charge or discharge priority order of the first battery and / or the second battery.

[0023] An advantage with this implementation form is that batterie(s) can be prioritized in an optimum order to ensure that prioritized batteries can be charged / discharged for optimal operation.

[0024] In an implementation form of a power control arrangement according to the first aspect, the charge or discharge priority order is based on a state-of-charge, a state of health, a failure, and a power or energy rating of the first battery and / or the second battery.

[0025] An advantage with this implementation form is that these parameters are relevant for determining the charge or discharge priority order of the batteries.

[0026] In an implementation form of a power control arrangement according to the first aspect, wherein the power bus is a DC bus, and wherein the power control arrangement is configured to: control a voltage of the DC bus to charge or discharge the first battery and / or the second battery.

[0027] This is a solution for controlling the charging and discharging of batteries connected to the DC bus without interfacing power electronics.

[0028] In an implementation form of a power control arrangement according to the first aspect, the power control arrangement is configured to: control the voltage of the DC bus to charge or discharge the first battery and / or the second battery further based on one or more electrical measurements of the first battery and / or the second battery.

[0029] An advantage with this implementation form is that electrical information about the batteries connected to the DC bus is used for controlling charging / discharging of the batteries.

[0030] In an implementation form of a power control arrangement according to the first aspect, the one or more electrical measurements comprises any of: a current measurement, a voltage measurement, a power measurement, and a state-of-charge measurement.

[0031] These are relevant parameters for controlling charging / discharging of the batteries.

[0032] In an implementation form of a power control arrangement according to the first aspect, the power control arrangement is configured to: control the voltage of the DC bus to charge or discharge the first battery and / or the second battery further based on an operator request.

[0033] Thus, the operator can directly influence the charging / discharging of the batteries.

[0034] In an implementation form of a power control arrangement according to the first aspect, the operator request comprises: a requested priority of the storage, a requested energy supply mode of the DC bus, and a requested reference voltage for the DC bus.

[0035] These are relevant parameters by which the operator can influence the charging / discharging of the batteries.

[0036] In an implementation form of a power control arrangement according to the first aspect, the controlling of the voltage of the DC bus comprises: control the voltage of the DC bus to maintain a state-of-charge of the first battery and / or a state-of-charge of the second battery within a charging bandwidth. The charging bandwidth may mean an acceptable state of charge bandwidth for the batteries. Thereby, the batteries connected to the DC bus can operate at optimal charging levels.

[0037] In an implementation form of a power control arrangement according to the first aspect, the charging bandwidth comprises 10-90%, or 15-85%, or 20-80%.

[0038] In an implementation form of a power control arrangement according to the first aspect, the power bus is an AC bus, and wherein the first battery is connected to the AC bus via a first DC / AC and AC / DC converter, and the second battery is connected to the AC bus via a second DC / AC and AC / DC converter.

[0039] According to a second aspect of the disclosure, the above-mentioned and other objectives are achieved with a mining / construction machine comprising a power control arrangement according to any one of the preceding claims.

[0040] In an implementation form of a mining / construction machine according to the second aspect, the power bus is connected to an external battery energy storage system; and wherein the power control arrangement is configured to: adapt the power limit margin of the power grid further based on a state-of charge of the external battery energy storage system.

[0041] An advantage with this implementation form is that also external batteries are considered for adapting the power limit margin.

[0042] According to a third aspect of the disclosure, the above mentioned and other objectives are achieved with a method for a power control arrangement comprising: a power bus connected to a power grid and configured to receive an input power from the power grid; a first battery connected to the power bus and configured to receive a power from the power bus or supply a first battery power to the power bus; at least one second battery connected to the power bus and configured to receive a power from the power bus or supply a second battery power to the power bus; and at least one load connected to the power bus and configured to receive an output power from the power bus; wherein the method comprises: adapting a power limit margin of the power grid based on a power supply mode of the power bus, wherein the power supply mode comprises that: only the input power from the power grid, or only the first battery power, or only the second battery power is supplied on the power bus; or a combination of the input power from the power grid and / or the first battery power and / or the second battery power is supplied on the power bus.

[0043] The method may be adapted in accordance with the above-mentioned embodiments of the power control arrangement according to the first aspect. The advantages of the method are the same as the advantages of the corresponding embodiments of the power control arrangement according to the first aspect.

[0044] According to further aspects of the present disclosure, the herein described methods are implemented by use of computer program products comprising instructions which, when the programs are executed by a computer, such as e.g., a control unit, cause the computer to carry out the steps of the methods according to any one of the herein described embodiments.

[0045] Further applications and advantages of embodiments of the disclosure will be apparent from the following detailed description.

[0046] Brief Description of the Drawings

[0047] The appended drawings are intended to clarify and explain different embodiments of the disclosure, in which:

[0048] Fig. 1 shows a power control arrangement according to embodiments of the disclosure;

[0049] Fig. 2 illustrates different power limit margins according to embodiments of the disclosure;

[0050] Fig. 3 shows a power control arrangement according to further embodiments of the disclosure; Fig. 4 illustrates charge / discharge of batteries connected to a DC bus according to embodiments of the disclosure;

[0051] Fig. 5 illustrates a mining / construction machine comprising a power control arrangement according to embodiments of the disclosure;

[0052] Fig. 6 shows a flow chart of a method according to embodiments of the disclosure; and

[0053] Fig. 7 shows exemplary mining / construction machines according to embodiments of the disclosure.

[0054] Detailed Description

[0055] Fig. 1 shows a power control arrangement 100 for a mining / construction machine according to embodiments of the disclosure. The power control arrangement 100 herein disclosed comprises a power bus 1 10 connected to a power grid 200 and configured to receive an input power (IP) from the power grid 200. The power control arrangement 100 also comprises a first battery 120 connected to the power bus 110 and configured to receive a power from the power bus 1 10 or supply a first battery power (BP1 ) to the power bus 110, and at least one second battery 130 connected to the power bus 1 10 and configured to receive a power from the power bus 1 10 or supply a second battery power (BP2) to the power bus 110. Thus, it is understood that the power control arrangement 100 may comprise two or more separate batteries connected to the power bus 1 10 and that each battery may either receive a power from the power bus 1 10, i.e., being charged with current / power by the power bus 1 10, or supply a power to the power bus 1 10, i.e., discharging current / power to the power bus 1 10.

[0056] The power control arrangement 100 further comprises at least one load 310 connected to the power bus 1 10. The load 310 is configured to receive an output power (OP) from the power bus 1 10. The load 310 may be any power consumer that needs electrical power for its functioning such as, for example, compressors, actuators, drills and electrical drivetrains. The power provided to the load 310 is thereby supplied through the power bus 1 10.

[0057] The power control arrangement 100 according to embodiments of the disclosure is configured to adapt a power limit margin of the power grid 200 based on a power supply mode of the power bus 1 10, where the power supply mode comprises only the input power from the power grid 200, or only the first battery power, or only the second battery power is supplied on the power bus 1 10; or a combination of the input power from the power grid 200 and / or the first battery power and / or the second battery power is supplied on the power bus 1 10.

[0058] Thus, the supply mode of the power bus 1 10 relates to which power source or which combination of power sources that supplies power to the power bus 1 10 at a certain time instance or time period. This means that the supply mode of the power bus 1 10 may involve one of the power sources only connected to the power bus 1 10 or any combination of the power sources, where the power sources comprise at least grid power and two or more batteries. For example, the supply mode of the power bus 1 10 may involve: only one of the grid power 200 or one of the two or more batteries 120, 130; or the grid power 200 and the first battery 120; or the grid power 200 and the second battery 130; or the first battery 120 and the second battery 130. It is further noted that also other power sources may be connected to the power bus 1 10 and configured to supply power to the power bus 110 as will be described in the following disclosure.

[0059] Generally, the supply mode of the power bus 1 10 varies as a function of time. Thus, in embodiments of the disclosure, the supply mode of the power bus 100 is a scheduled power supply mode of the power bus 1 10 which means that it is determined in advance which supply mode that should be used at a specific time period according to a schedule. Thereby, scheduled power demand of the load(s) may be met.

[0060] Fig. 2 illustrates different power limit margins for different time periods. The diagram in Fig. 2 shows the input power supplied by the power grid 200 as a function of time. As shown in Fig. 2, the upper power limit of the power grid 200 is given as a constant value which is the normal case. During a first time period T1 , the maximum input power from the power grid 200 is P1 and the power limit margin is M1 , i.e., the difference between the upper power limit and the maximum input power. During a second time period T2 after the first time period T1 , the maximum input power is P2 and the power limit margin is M2, which means that the maximum input power has increased from the first time period T 1 and the power limit margin therefore has decreased from M1 to M2. During a third time period T3 after the second time period T2, the maximum input power is P3 and the power limit margin is M3, which means that the maximum input power has decreased, and the power limit margin has increased from the second time period T2.

[0061] The input powers P1 , P2 and P3 are here maximum allowed input power of the power grid 200 at a certain operating time instance or time period. In other words, during the first time period T1 , it is decided to have power limit margin M1 and based on an upper power limit of the power grid 200, which means that the maximum allowed input power that is allowed during the first time period T1 is P1. This implies that during the first time period T1 , the input power of the power grid 200 can be anything between zero to P1 . Further, in the second time period T2, assuming that the supply mode of the DC bus 1 10 has changed, it is decided to have power limit margin equal to M2 which allows to have maximum allowed input power of the power grid 200 up to P2. For example, assume that the upper power limit of the power grid 200 based on power transfer line and power transfer equipment is 500 kW at the first time period T1 , it is decided to have power limit margin M1 as 10OkW which means in the first time period T 1 , that the maximum allowed input power of the power grid 200 is 400 KW, i.e., the maximum allowed input power of the power grid 200 can be any of 0, 100, 200, 350 up to 400kW during the first time period T1 . Then based on change in the supply mode of the DC bus 1 10 it is decided in the second time period T2 to have a power limit margin M2 equal to 50 KW so the maximum allowed input power of the power grid 200 can be 450 kW, i.e., the maximum allowed input power of the power grid 200 can be any of 0, 100, 200, 350 up to 450kW during the second time period T2.

[0062] Hence, in embodiments of the disclosure, the adapting of the power limit margin implies increasing or decreasing the power limit margin. It may further be noted that the power limit margin is based on a difference between the upper power limit of the power grid 200 and maximum allowed input power from the grid. The grid power limit margin is smallest during the second time period T2 and largest during the third time period T3 which implies that the power outtake is larger during the second time period T2, but the safe margin is smaller which implies less robustness against power grid failure or temporary capacity reduction during the second time period T2. The grid power limit margin is hence how much difference the power control arrangement 100 wants to keep between the power reference and the grid power limit for allowing maximum power outtake while having a suitable safe margin so that the power supply to the power bus 1 10 is robust.

[0063] It is noted that the diagram in Fig. 2 only shows the change in power in discrete power steps for different time periods for easy understanding of basic principles of the disclosure, but it is understood that the change of the input power also can be continuous as a function of time for fast adaptation of the power limit margin to different input / output scenarios.

[0064] Fig. 3 shows a power control arrangement 100 according to further embodiments of the disclosure. A power connection line 210 interconnecting the power grid 200 to the load 310 is shown in the topology of Fig. 3. The power transfer capability of the power connection line 210 depends on an electrical transfer chain comprising all devices, elements and components forming the power connection line 210 such as cables, transformers, converters, filters etc., and the power transfer capability of the power connection line 210 may be decided by the weakest link in this electrical transfer chain. Therefore, in embodiments of the disclosure, the power control arrangement 100 is configured to adapt the power limit margin further based on a maximum power transfer capability of a power connection line 210 interconnecting the power grid 200 and the load 310. Thereby, maximum power can be supplied to the load 310 while safeguard that the supplied power is within the power transfer capability of the power connection line 210. Else, there would be a risk of power transfer failure due to overloading of the power connection line 210.

[0065] As also noted from Fig. 3, the power control arrangement 100 herein disclosed may also include a controller arrangement 150. Thus, a plurality of control lines, illustrated with dashed lines, interconnects the controller arrangement 150 with the other devices of the power control arrangement 100 so that the controller arrangement 150 can control these other devices. Thereby, the controller arrangement 150 can adapt the power limit margin of the power grid 200 based on input parameters, input information elements, input data etc. The controller arrangement 150 may therefore comprise a processor, a memory and a communication interface for obtaining the input parameters, input information elements and input data and use them in a control algorithm for adapting and controlling the power limit margin. The dashed lines in Fig. 3 may therefore also illustrate control interfaces by which the controller arrangement 150 controls the power control arrangement 100.

[0066] Furthermore, Fig. 4 illustrates charging / discharging of batteries connected to the power bus 1 10 according to embodiments of the disclosure when the power bus is a direct current (DC) power bus. Generally, batteries connected to the DC bus 100 may either charge current / power from the DC bus 1 10 or discharge current / power to the DC bus 1 10 which implies that the electrical current may flow in two directions between the batteries and the DC bus 1 10. Different parameters, information elements and data may therefore be considered for controlling the charging / discharging of the batteries of the power control arrangement 100.

[0067] One such consideration is the schedule of the load 310. Thus, the first battery 120 and / or the second battery 130 is charged or discharged based on a load schedule of the load 310. The schedule of the load 310 provides information about the planned load during future time periods which directly has implications for the demanded power by the load 310 during these future time periods. It is therefore important to adapt the charging / discharging of the batteries to the load schedule so that enough power is available for the load 310 and that the batteries can operate at an optimal charging level or charging interval.

[0068] The first battery 120 and / or the second battery 130 may also be charged / discharged based on a charging / discharging priority order of the first battery 120 and the second battery 130. The charging / discharging priority order determines the order of charging / discharging of the batteries. The charging / discharging priority order may be determined based on any of:

[0069] • A state-of-charge of a battery which gives the remaining power capacity available in the battery; and / or

[0070] • A state of health of a battery which is the condition of the battery e.g., due to age and use; and / or

[0071] • A failure of a battery which directly impacts the capacity of the battery; and / or • A power rating or energy rating of the first battery 120 and / or the second battery 130 which can be translated to the power capacity of each battery connected to the DC bus 110.

[0072] Furthermore, by controlling a voltage Vbus of the DC bus 1 10 also the charging / discharging of the first battery 120 and / or the second battery 130 may be controlled. Depending on a difference in potential between the voltage Vbus of the DC bus 1 10 and the voltage of a battery, a battery connected to the DC bus 100 will either be charged or discharged. That is, if the potential is higher in the battery than in the DC bus 1 10, the battery will be discharged, and a current will flow from the battery to the DC bus 110. On the other hand, if the potential is lower in the battery than in the DC bus 1 10, the battery will be charged, and a current will flow from the DC bus 110 to the battery. Thereby, the state-of-charge of the first battery 120 and / or a state-of- charge of the second battery 130 may be maintained within a charging bandwidth so that the batteries can operate efficiently at optimum charging intervals and thus also the lifetime of the batteries may be prolonged giving economic benefits. Non-limiting examples of applicable charging bandwidths are 10-90%, or 15-85%, or 20-80%.

[0073] For optimizing the charging / discharging of batteries, electrical measurements of the first battery 120 and / or the second battery 130 may also be considered. The electrical measurements give information about the electrical condition of the batteries. Relevant electrical measurements in this respect comprise any of:

[0074] • A current measurement from which the power of the battery may be derived; and / or

[0075] • A voltage measurement from which the power of the battery may be derived; and / or

[0076] • A power measurement, i.e., a direct indication of the power of the battery; and / or

[0077] • A state-of-charge measurement which gives information about the capacity of the battery.

[0078] Further, commands from an operator in charge of mining / construction machines may be important to consider when charging / discharging batteries connected to the DC bus 1 10. Thus, the voltage Vbus of the DC bus 1 10 may further be controlled based on an operator request / command. The operator request may comprise any of:

[0079] • A requested priority of the energy storage that relates to which one of multiple energy storages (e.g., batteries) to charge / discharge in multiple energy storage scenarios; and / or

[0080] • A requested energy supply mode of the DC bus 110, i.e., any of the energy supply modes of the DC bus 110 as previous described which may be requested by the operator; and / or

[0081] • A requested reference voltage for the DC bus 110 which will have a direct impact on the charging / discharging of the batteries connected to the DC bus 110.

[0082] In embodiments of the invention, which is not shown in the Figs., the power bus 110 is an alternating current (AC) power bus. In such cases, the first battery 120 is connected to the AC bus via a first DC / AC and AC / DC converter, while the second battery 130 is connected to the AC bus via a second DC / AC and AC / DC converter. Thus, the converters of the batteries can convert a DC of a battery to an AC of the AC bus, and vice versa. In this respect, the power control arrangement 100 may also comprise transformers and other devices and components for DC / AC and AC / DC conversion.

[0083] Moreover, Fig. 5 illustrates a mining / construction machine 300 comprising a power control arrangement 100 according to embodiments of the disclosure. As shown in the example of Fig. 5, the power control arrangement 100 may be an integral part of the mining / construction machine 300. The DC bus 1 10 of the power control arrangement 100 is connected to a power grid 200 as previously described. However, an external battery energy storage system 140 may also be connected to the DC bus 1 10. The external battery energy storage system 140 may charge current to the DC bus 1 10 or discharge current from the DC bus 1 10. Therefore, the power limit margin of the power grid 200 may further be based on a state-of-charge of the external battery energy storage system 140 in analogue reasoning to the previous discussion about the state- of charge of the batteries 120, 130 when being charged / discharged by the DC bus 1 10.

[0084] Fig. 6 shows a flow chart of a method according to embodiments of the disclosure. As aforementioned, the power control arrangement 100 herein disclosed comprises: a power bus 110 connected to a power grid 200 and configured to receive an input power from the power grid 200; a first battery 120 connected to the power bus 110 and configured to receive a power from the power bus 1 10 or supply a first battery power to the power bus 1 10; at least one second battery 130 connected to the power bus 1 10 and configured to receive a power from the power bus 1 10 or supply a second battery power to the power bus 1 10; and at least one load 310 connected to the power bus 1 10 and configured to receive an output power from the power bus 1 10.

[0085] The method 400 comprises: adapting 402 a power limit margin of the power grid 200 based on a power supply mode of the power bus 1 10, wherein the power supply mode comprises that: only the input power from the power grid 200, or only the first battery power, or only the second battery power is supplied on the power bus 1 10; or a combination of the input power from the power grid 200 and / or the first battery power and / or the second battery power is supplied on the power bus 1 10.

[0086] Embodiments of the method 400 may fully correspond to all embodiments of the power control arrangement 100 herein disclosed. Thus, the power control arrangement 100 comprises one or more control devices / units arranged / configured / programmed with instruction to carry out the method 400.

[0087] Fig. 7 illustrates examples of a mining / construction machine 300 that may be used with the present power control arrangement 100. The mining / construction machine 300 may therefore include such a power control arrangement 100.

[0088] The mining / construction machine 300 may be any type of electrified machine or vehicle used in a mining and / or construction environment / site such as e.g., a drill rig, a truck, a loader, a digging machine, etc. With reference to Fig. 7, the mining / construction machine 300 may e.g., be a drill rig, a loading, hauling and dumping (LHD) machine or a mine truck but is not limited thereto.

[0089] Finally, it should be understood that the disclosure is not limited to the embodiments described above, but also relates to and incorporates all embodiments within the scope of the appended independent claims.

Claims

CLAIMS1. A power control arrangement (100) for a mining / construction machine (300), the power control arrangement (100) comprising: a power bus (110) connected to a power grid (200) and configured to receive an input power, IP, from the power grid (200); a first battery (120) connected to the power bus (1 10) and configured to receive a power from the power bus (110) or supply a first battery power (BP1 ) to the power bus (1 10); at least one second battery (130) connected to the power bus (1 10) and configured to receive a power from the power bus (1 10) or supply a second battery power (BP2) to the power bus (1 10); and at least one load (310) connected to the power bus (110) and configured to receive an output power, OP, from the power bus (1 10); wherein the power control arrangement (100) is configured to: adapt a power limit margin of the power grid (200) based on a power supply mode of the power bus (1 10), wherein the power supply mode comprises that: only the input power, IP, from the power grid (200), or only the first battery power (BP1 ), or only the second battery power (BP2) is supplied on the power bus (1 10); or a combination of the input power, IP, from the power grid (200) and / or the first battery power (BP1 ) and / or the second battery power (BP2) is supplied on the power bus (1 10).

2. The power control arrangement (100) according to claim 1 , wherein the power supply mode is a scheduled power supply mode of the power bus (1 10).

3. The power control arrangement (100) according to claim 1 or 2, wherein the power limit margin is based on a difference between an upper power limit of the power grid (200) and maximum allowed input power from the power grid (200).

4. The power control arrangement (100) according to any one of the preceding claims, configured to:adapt the power limit margin further based on a maximum power transfer capability of a power connection line (210) interconnecting the power grid (200) and the load (310).

5. The power control arrangement (100) according to any one of the preceding claims, wherein the adapting of the power limit margin of the power grid (200) comprises: increasing or decreasing the power limit margin.

6. The power control arrangement (100) according to any one of the preceding claims, configured to: charge or discharge the first battery (120) and / or the second battery (130) based on a schedule of the load (310).

7. The power control arrangement (100) according to claim 6, configured to: charge or discharge the first battery (120) and / or the second battery (130) based on the schedule of the load (310) and a charge or discharge priority order of the first battery (120) and / or the second battery (130).

8. The power control arrangement (100) according to claim 7, wherein the charge or discharge priority order is based on a state-of-charge, a state of health, a failure, and a power or energy rating of the first battery (120) and / or the second battery (130).

9. The power control arrangement (100) according to any one of claims 6 to 8, wherein the power bus (100) is a DC bus, and wherein the power control arrangement (100) is configured to: control a voltage (Vbus) of the DC bus (1 10) to charge or discharge the first battery (120) and / or the second battery (130).

10. The power control arrangement (100) according to claim 9, configured to: control the voltage (Vbus) of the DC bus (1 10) to charge or discharge the first battery (120) and / or the second battery (130) further based on one or more electrical measurements of the first battery (120) and / or the second battery (130).1 1. The power control arrangement (100) according to claim 10, wherein the one or more electrical measurements comprises any of: a current measurement, a voltage measurement, a power measurement, and a state-of-charge measurement.

12. The power control arrangement (100) according to any one of claims 6 to 1 1 , configured to: control the voltage (Vbus) of the DC bus (1 10) to charge or discharge the first battery (120) and / or the second battery (130) further based on an operator request.

13. The power control arrangement (100) according to claim 12, wherein the operator request comprises: a requested priority of the storage, a requested energy supply mode of the DC bus (110), and a requested reference voltage for the DC bus (1 10).

14. The power control arrangement (100) according to any one of claims 9 to 13, wherein the controlling of the voltage (Vbus) of the DC bus (110) comprises: control the voltage (Vbus) of the DC bus (110) to maintain a state-of-charge of the first battery (120) and / or a state-of-charge of the second battery (130) within a charging bandwidth.

15. The power control arrangement (100) according to claim 14, wherein the charging bandwidth comprises 10-90%, or 15-85%, or 20-80%.

16. The power control arrangement (100) according to any one of claims 6 to 8, wherein the power bus (1 10) is an AC bus, and wherein the first battery (120) is connected to the AC bus via a first DC / AC and AC / DC converter, and the second battery (130) is connected to the AC bus via a second DC / AC and AC / DC converter.

17. A mining / construction machine (300) comprising a power control arrangement (100) according to any one of the preceding claims.

18. The mining / construction machine (300) according to claim 17, wherein the power bus (110) is connected to an external battery energy storage system (140); and wherein the power control arrangement (100) is configured to: adapt the power limit margin of the power grid (200) further based on a state-of charge of the external battery energy storage system (140).

19. A method (400) for a power control arrangement (100) comprising: a power bus (110) connected to a power grid (200) and configured to receive an input power, IP, from the power grid (200); a first battery (120) connected to the power bus (1 10) and configured to receive a power from the power bus (110) or supply a first battery power (BP1 ) to the power bus (1 10); at least one second battery (130) connected to the power bus (1 10) and configured to receive a power from the power bus (1 10) or supply a second battery power (BP2) to the power bus (1 10); and at least one load (310) connected to the power bus (110) and configured to receive an output power, OP, from the power bus (1 10); wherein the method (400) comprises: adapting (402) a power limit margin of the power grid (200) based on a power supply mode of the power bus (1 10), wherein the power supply mode comprises that: only the input power, IP, from the power grid (200), or only the first battery power (BP1 ), or only the second battery power (BP2) is supplied on the power bus (1 10); or a combination of the input power, IP, from the power grid (200) and / or the first battery power (BP1 ) and / or the second battery power (BP2) is supplied on the power bus (1 10).

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