An electrical power system for a mining / construction

Abstract

The disclosure relates to an electrical power system (100) for a mining / construction vehicle (200), the electrical power system (100) comprising: an input (102) connected to at least one DC power source (120) and being configured to receive a DC input power (DC1) from the DC power source (120); at least one galvanic isolated DC / DC converter (110) connected to the input (102), the galvanic isolated DC / DC converter (110) comprising a transformer (112) having a primary winding (114) and a secondary winding (116) having a winding turns ratio, and wherein the galvanic isolated DC / DC converter (110) is configured to convert the DC input power (DC1) into a DC output power (DC2) with a conversion ratio substantially equal to the winding turns ratio; and an output (104) connected to the galvanic isolated DC / DC converter (110) and being configured to supply the DC output power (DC2) to a DC bus (120) of the mining / construction vehicle (200) Furthermore, the disclosure also relates to a mining / construction vehicle comprising such a power system.

Description

[0001] AN ELECTRICAL POWER SYSTEM FOR A MINING / CONSTRUCTION

[0002] Technical Field

[0003] The disclosure relates to an electrical power system for a mining / construction vehicle. Furthermore, the disclosure also relates to a mining / construction vehicle comprising such an electrical power system.

[0004] Background

[0005] Traditionally, a mining / construction vehicle has been powered by one or more combustion engines such as diesel engines. However, electrified mining / construction vehicles provide an opportunity to reduce the environmental footprint and create a healthier work environment in mining environments. Compared to mining / construction vehicles powered by diesel engines, the electrified mining / construction vehicle are emission free and can hence bring considerable savings, especially for ventilation and cooling in the mining environments.

[0006] The mining / construction vehicle comprises an electrical power system which is adapted to power different loads of the drill rig. Such loads may relate to pumps, compressors, actuators, drivetrains, motors, etc. Also, power storage units of the electrified mining / construction vehicle may need to be charged. Examples of power storage units are batteries, capacitors, and fuel cells. The power storage units may thus form an on-board electrical storage system (ESS) of the electrified drill rig.

[0007] An aspect of such electrical power system is the conversion of a direct current (DC) power level to another DC power level and / or alternating current (AC). It is an aim that the electrical power conversion is efficient.

[0008] Summary

[0009] An objective of embodiments of the disclosure is to provide a solution which mitigates or solves the drawbacks of conventional solutions.

[0010] Another objective of embodiments of the disclosure is to provide an electrical power system for a mining / construction vehicle having higher efficiency compared to conventional solutions. The above and further objectives are solved by the subject matter of the appended independent claims.

[0011] According to a first aspect of the disclosure, the above mentioned and other objectives are achieved with an electrical power system for a mining / construction vehicle, the electrical power system comprising: an input connected to at least one DC power source and being configured to receive a DC input power from the DC power source; at least one galvanic isolated DC / DC converter connected to the input, the galvanic isolated DC / DC converter comprising a transformer having a primary winding and a secondary winding having a winding turns ratio tf, and wherein the galvanic isolated DC / DC converter is configured to convert the DC input power into a DC output power with a conversion ratio cfequal to the winding turns ratio tf; and an output connected to the galvanic isolated DC / DC converter and being configured to supply the DC output power to a DC bus of the mining / construction vehicle.

[0012] An advantage of the electrical power system according to the first aspect is that the size and weight of the electrical power system can be smaller and lower compared to conventional solutions due to the circuit topology herein disclosed. Further, the conversion efficiency of the present electrical power system is also improved in comparison to conventional solutions due the operation and topology of the present electrical power system.

[0013] In an embodiment of an electrical power system according to the first aspect, wherein the galvanic isolated DC / DC converter is configured to operate in a medium frequency range and / or in a high frequency range.

[0014] Thereby, the electrical power system may operate in the medium and high frequency ranges such as in frequencies equal to or above 1 kHz.

[0015] In an embodiment of an electrical power system according to the first aspect, the electrical power system comprises: two or more galvanic isolated DC / DC converters connected to the input and the output, respectively.

[0016] Thus, different number of galvanic isolated DC / DC converters can be employed and hence the electrical power system can easily be adapted to different load and power storage applications having different power requirements such as voltage levels and current levels.

[0017] In an embodiment of an electrical power system according to the first aspect, the two or more galvanic isolated DC / DC converters are connected in series or in parallel at the input; and / or the two or more galvanic isolated DC / DC converters are connected in series or in parallel at the output.

[0018] Thereby, flexible circuit topology is provided to suit different applications.

[0019] In an embodiment of an electrical power system according to the first aspect, the input comprises a positive terminal capacitor and a negative terminal capacitor.

[0020] In an embodiment of an electrical power system according to the first aspect, the electrical power system comprises: at least one DC / DC converter comprising an input connected to the DC bus and an output connected to a DC power storage unit of the mining / construction vehicle.

[0021] Thereby, the DC power storage unit of the mining / construction vehicle can be charged and / or powered.

[0022] In an embodiment of an electrical power system according to the first aspect, the DC / DC converter is configured to control a charging / discharging or a power flow of the DC power storage unit.

[0023] In an embodiment of an electrical power system according to the first aspect, wherein the DC power storage unit is any of: a battery, a fuel cell and a capacitor. In an embodiment of an electrical power system according to the first aspect, the electrical power system comprises: at least one DC / AC converter comprising an input connected to the DC bus and an output connected to an electrical load of the mining / construction vehicle.

[0024] Thereby, the electrical load of the mining / construction vehicle can be powered.

[0025] In an embodiment of an electrical power system according to the first aspect, the DC / AC converter is a three-phase DC / AC converter.

[0026] Thereby, high power loads of the mining / construction vehicle can be powered.

[0027] In an embodiment of an electrical power system according to the first aspect, the electrical load is any of: a motor, a compressor, and a pump.

[0028] In an embodiment of an electrical power system according to the first aspect, the electrical power system comprises: an AC / DC converter comprising an input connected to an AC grid and an output connected to the input, the AC / DC converter being configured to receive an AC power from the AC grid and convert the AC power to the DC input power.

[0029] In an embodiment of an electrical power system according to the first aspect, the AC / DC converter is configured to convert the AC power to the DC input power with a fixed gain in its sweet spot region.

[0030] Fixed gain may be understood that the ratio between the AC voltage and the DC voltage has a fixed or near fixed value. The AC / DC converter thus operates in or as close to the maximum efficiency when converting input AC voltage to output DC voltage.

[0031] Thereby, maximum efficiency is possible when converting AC to DC using the present AC / DC converter. In an embodiment of an electrical power system according to the first aspect, the AC / DC converter comprises one or more transformers, one or more filters and one or more rectifiers.

[0032] Thereby, different configurations of the AC / DC converter can be provided.

[0033] In an embodiment of an electrical power system according to the first aspect, the AC / DC converter is a three-phase AC / DC converter.

[0034] In an embodiment of an electrical power system according to the first aspect, the DC power source is a DC grid.

[0035] In an embodiment of an electrical power system according to the first aspect, wherein the DC bus comprises a capacitor.

[0036] In an embodiment of an electrical power system according to the first aspect, the electrical power system comprises: a controller configured to control the electrical power system.

[0037] According to a second aspect of the disclosure, the above mentioned and other objectives are achieved with a mining / construction vehicle comprising: an electrical power system according to embodiments of the disclosure, and at least one DC power storage unit and / or an electrical load connected to the DC bus.

[0038] Further applications and advantages of embodiments of the disclosure will be apparent from the following detailed description.

[0039] Brief Description of the Drawings

[0040] The appended drawings are intended to clarify and explain different embodiments of the disclosure, in which:

[0041] - Fig. 1 shows schematically an electrical power system according to embodiments of the disclosure; - Fig. 2 shows a transformer in a galvanic isolated converter according to embodiments of the disclosure;

[0042] - Fig. 3 shows an electrical power system comprising DC / DC and DC / AC converters for a mining / construction vehicle according to embodiments of the disclosure;

[0043] - Fig. 4a - 4c illustrate different AC / DC converters employed in the electrical power system according to embodiments of the disclosure;

[0044] - Fig. 5 shows a power system in more detail according to embodiments of the disclosure; and

[0045] - Fig. 6 shows a mining / construction vehicle according to embodiments of the disclosure.

[0046] Detailed Description

[0047] Fig. 1 schematically shows an electrical power system 100 for a mining / construction vehicle 200 according to embodiments of the disclosure and Fig. 2 illustrates a transformer 112 of a galvanic isolated converter 110 according to embodiments of the invention. The herein disclosed electrical power system 100 comprises an input 102 connected to at least one DC power source 120 and being configured to receive a DC input power DC1 from the DC power source 120. The DC power source 120 may be any suitable DC source providing / feeding DC voltage to the electrical power system 100.

[0048] The electrical power system 100 further comprises at least one galvanic isolated DC / DC converter 110 which is connected to the input 102. In this respect the galvanic isolated DC / DC converter 110 comprises a transformer 112 having a primary winding 114 and a secondary winding 116. The transformer 112 has a winding turns ratio denoted tf. The present galvanic isolated DC / DC converter 110 is configured to convert the DC input power DC1 from the DC power source 120 into a DC output power DC2 with a conversion ratio cfwhich is substantially equal to the winding turns ratio tf. This may also be expressed such that the DC / DC voltage conversion is dependent on the winding turns ratio of the transformer 112.

[0049] The electrical power system 100 also comprises an output 104 connected to the galvanic isolated DC / DC converter 110 and being configured to supply the DC output power DC2 to a DC bus 120 of the mining / construction vehicle 200. Thereby, DC power is provided to the mining / construction vehicle 200 for use in different applications which will be described in the following disclosure.

[0050] The winding turns ratio ttis the ratio between the number of turns in the primary winding in relation to the number of turns in the secondary winding. Thus, according to the disclosure, the DC / DC conversion ratio cfis directly related to the winding turns ratio ttfor high performance conversion. It may however be noted that the DC / DC conversion ratio cfmay differ from the winding turns ratio ttin practical implementation due to e.g., characteristics of electrical components and physical parameters such as temperature, material used, etc. Hence, the DC / DC conversion ratio cfmay deviate slightly from the winding turns ratio tf. This may also be expressed that the DC / DC conversion ratio cfmay be defined in terms of an interval around the value of the winding turns ratio tf. The interval may be a percentage of the value of the winding turns ratio tf. For example, less than 5%, or less than 2.5% or less than 1 %.

[0051] In embodiments of the disclosure, the galvanic isolated DC / DC converter 110 is configured to operate in a medium frequency range and / or in a high frequency range. Normally this frequency is higher than grid frequency such as 50 or 60 Hz and generally equal or higher than 1 kHz.

[0052] Fig. 3 shows an electrical power system 100 comprising a plurality of galvanic isolated converters 110, DC / DC converters 130 and DC / AC converters 140 connected to the DC bus 120 according to embodiments of the disclosure. Thus, the electrical power system 100 may comprise two or more galvanic isolated DC / DC converters 110, 110' which are connected to the input 102 and the output 104, respectively. Depending on the application case the circuit topology of the electrical power system 100 may vary and the two or more galvanic isolated DC / DC converters 110, 110' may be connected in series or in parallel at the input 102. Further, the two or more galvanic isolated DC / DC converters 110, 110' may be connected in series or in parallel at the output 104. Thereby, different topological configurations may be provided for flexible adaptation to different applications. Furthermore, in embodiments of the disclosure the electrical power system 100 comprises at least one DC / DC converter 130 having an input 132 connected to the DC bus 120 and an output 132 connected to a DC power storage unit 210 of the mining / construction vehicle 200. Thereby, the DC power supplied by the galvanic isolated DC / DC converters 110, 110' may be used for charging or providing a power flow to the DC power storage unit 210 depending on type of storage unit employed. Non-limiting examples of power storage units are batteries, fuel cells and capacitors such as super capacitors. Batteries and capacitors are charged while fuel cells are provided with a power flow.

[0053] Moreover, the electrical power system 100 may also comprise at least one DC / AC converter 140 having an input 142 connected to the DC bus 120 and an output 144 connected to an electrical load 220 of the mining / construction vehicle 200. Non-limiting examples of electrical loads 220 of the mining / construction vehicle 200 are motors, compressors, and pumps. In some cases, the electrical loads 220 require high voltage power which implies that the DC / AC converter 140 may be a three-phase DC / AC converter in such cases.

[0054] It may further be noted that a power storage unit may provide DC power to the DC bus 120 after having been charged with power, i.e., to discharge its DC power into the DC bus 120. The DC power discharged into the DC bus 120 may be converted by the DC / AC converter 140 to AC power for powering the mentioned electrical load 220 of the mining / construction vehicle 200. Thus, the non-galvanic isolated DC / DC converter 130 may be configured to control a charging / discharging or the power flow of the DC power storage unit 210 according to embodiments of the disclosure. The galvanic isolated DC / DC converter 110 is not controlling the power flow, but the non-galvanic isolated DC / DC converter 130 is in embodiments configured to detect the operation of the drill rig 200, such as drill status, and inject or absorb electrical power accordingly to limit the power coming from galvanic isolated DC / DC converter 110 to a certain limit for improved performance. In this respect the electrical power system 100 may also comprise a controller 160 configured to control the different parts of the electrical power system 100 such as DC / DC converters, AC / DC converters, DC / AC converters DC buses, switches, input ports, output ports, etc. The controller 160 may be in wired and / or wireless communication with the different parts of the electrical power system 100 using suitable communication interfaces and protocols. The controller 160 may therefore include a processor, a memory and a computer program running in the processor. The processor may be referred to as one or more general-purpose central processing units (CPUs), one or more digital signal processors (DSPs), one or more application-specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs), one or more programmable logic devices, one or more discrete gates, one or more transistor logic devices, one or more discrete hardware components, or one or more chipsets. The memory may be a readonly memory, a random access memory (RAM), or a non-volatile RAM (NVRAM).

[0055] As previously mentioned, the herein disclosed electrical power system 100 is connected to a DC power source. One example of a DC power source is an AC / DC converter 150 configured to convert AC to DC, and another example is a DC grid 320. The electrical power system 100 may be connected to either or both of the mentioned DC power sources as also illustrated in Fig. 3.

[0056] The AC / DC converter 150 is connected to an AC grid 310 and is therefore configured to convert the AC power from the AC grid 310 to DC power and thus acting as a DC source for the electrical power system 100. Hence, in general terms the AC / DC converter 150 includes an input 152 connected to the AC grid 310 and an output 154 connected to the input 102. The AC / DC converter 150 is configured to receive an AC power AC1 from the AC grid 310 and convert the AC power AC1 to the DC input power DC1.

[0057] In embodiments of the disclosure, the AC / DC converter 150 is configured to convert the AC power AC1 to the DC input power DC1 with a fixed or near fixed gain in its sweet spot region for higher conversion efficiency.

[0058] Fig. 4 illustrates different types of AC / DC converters 150 that may be employed in the electrical power system 100 according to embodiments of the disclosure.

[0059] In an example of the disclosure as shown in Fig. 4a, the AC / DC converter 150 comprises a line interphase transformer 170 at the input 152 connected with two diode rectifiers 171 at the output 154, which may be 6-pulse diode rectifiers in a three-phase application.

[0060] In another example of the disclosure as shown in Fig. 4b, the AC / DC converter 150 comprises a LCL filter 172 at the input 152 connected with a two- or three level active rectifier 173 at the output 154.

[0061] In yet another example of the disclosure as shown in Fig. 4c, the AC / DC converter 150 comprises an LC filter 174 at the input 152 connected with a diode rectifier 175 at the output 154.

[0062] Thus, in general the AC / DC converter 150 may comprise any of: one or more transformers, one or more filters and one or more rectifiers connected between the input 152 and the output 154 of the AC / DC converter 150.

[0063] Fig. 5 shows an electrical power system 100 in more detail according to further embodiments of the disclosure. As shown the AC / DC converter 150 may be a three- phase AC / DC converter and is thus configured to receive a three-phase AC from the AC grid 310 and convert the three-phase AC to DC. The electrical power system 100 may also be directly connected to a DC grid 320 as the DC power source 120 and in such cases no AC / DC converter is needed. However, embodiments of the disclosure are not limited thereto and e.g., the line interphase transformer can be a transformer or means of coupled inductors, e.g. line interphase transformer, that takes three-phase AC input and outputs multiples of three-phase AC output, where each three-phase AC output may be connected to a 6-pulse diode rectifier. The output of the diode rectifier can be series or parallel connected. These embodiments are not shown in the drawings.

[0064] It is also noted that the input 102 of the electrical power system 100 may comprise a positive terminal capacitor Ci and a negative terminal capacitor C2. That is, a positive terminal capacitor Ci which is connected between the positive terminal of the output of the DC source and the input of the galvanic isolated DC / DC converters 110. Correspondingly, a negative terminal capacitor C2 which is connected between the negative terminal of the output of the DC source and the input of the galvanic isolated DC / DC converters 100. The values of the positive terminal capacitor Ci and the negative terminal capacitor C2are selected to suit the application e.g. having values to ensure system voltage dynamics and limit voltage ripples.

[0065] Further, the positive output terminal of the galvanic isolated DC / DC converters 110 is connected to the positive terminal of the DC bus 120 while the negative output terminal of the galvanic isolated DC / DC converters 110 is connected to the negative terminal of the DC bus 120. A DC bus capacitor CBUS is connected between the positive and negative terminals of the DC bus 120. One or more DC / DC converters 130 and / or one or more DC / AC converters 140 are connected to the positive and negative terminals of the DC bus 120. The value of the CBUS is dependent on the application e.g. having values to ensure system voltage dynamics and limit voltage ripples.

[0066] Fig. 6 shows an example of a mining / construction vehicle 200 comprising an electrical power system 100 according to embodiments of the disclosure. The mining / construction vehicle 200 may be any type of electrified 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. The mining / construction vehicle 200 may e.g., be a drill rig, a loading, hauling and dumping (LHD) machine or a mine truck but is not limited thereto.

[0067] Fig. 6 shows the example when the mining / construction vehicle 200 is an electrical drill rig comprising the electrical power system 100 according to embodiments of the disclosure and at least one DC power storage unit 210 and / or an electrical load 220 connected to the DC bus 120. The electrical power system 100 may be fully or partially collocated with the mining / construction vehicle 200. In the latter example one or more electrical power cables may connect the different parts of the electrical power system 100 and the power storage units 210 and / or electrical loads 220 of the mining / construction vehicle 200.

[0068] The electrical drill rig may be a stationary or a mobile drill rig and Fig. 6 illustrates an exemplary underground electrified drilling rig with which embodiments of the disclosure may be utilised. Embodiments of the present disclosuree is, however, applicable to any mining and / or construction vehicle. For example, the disclosure is applicable for drilling rigs being utilised in tunnelling, surface mining, underground mining, rock reinforcement and raise boring. The drilling rigs may be used, e.g., for drilling blast holes, grout holes, holes for installing rock bolts, water wells and other wells, as well as for piling and foundations drilling etc. The drilling rigs may comprise a carrier and one or more booms attached to the carrier, where the booms may carry associated drilling machines and / or other tools. The electrified drilling rig may be hydraulically driven and power supplied from one or more hydraulic pumps, which in turn are driven by one or more electric motors. The drilling process may be controlled by an operator from a cabin or be remotely controlled or be configured to operate autonomously.

[0069] The electrified drilling rig may comprise a control system comprising at least one control unit, which controls various functions of the drilling rig 100, e.g., by suitable control of various actuators / motors / pumps etc. The control system may also control the electrical power system 100 and may fully or partially be integrated with the controller configured to control the different parts of the electrical power system 100.

[0070] The electrified drilling rig may further comprise more than one control unit, where each control unit, respectively, may be arranged to be responsible for different functions of the electrified drilling rig. The control unit may comprise a data processing unit which can be constituted by a processor, such as a digital signal processor. The control unit may be controlled by means of a computer program that is, e.g., built into the processor or being connected thereto in a memory. The computer program may be generated by means of an appropriate programming language and be stored in a non-transitory computer memory that is integrated in the processor or form a separate part of the control unit.

[0071] 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. An electrical power system (100) for a mining / construction vehicle (200), the electrical power system (100) comprising: an input (102) connected to at least one DC power source (120) and being configured to receive a DC input power (DC1 ) from the DC power source (120); at least one galvanic isolated DC / DC converter (110) connected to the input (102), the galvanic isolated DC / DC converter (110) comprising a transformer (112) having a primary winding (114) and a secondary winding (116) having a winding turns ratio tj, and wherein the galvanic isolated DC / DC converter (110) is configured to convert the DC input power (DC1 ) into a DC output power (DC2) with a conversion ratio ci substantially equal to the winding turns ratio tf; and an output (104) connected to the galvanic isolated DC / DC converter (110) and being configured to supply the DC output power (DC2) to a DC bus (120) of the mining / construction vehicle (200).

2. The electrical power system (100) according to claim 1 , wherein the galvanic isolated DC / DC converter (110) is configured to operate in a medium frequency range and / or in a high frequency range.

3. The electrical power system (100) according to claim 1 or 2, wherein the electrical power system (100) comprises: two or more galvanic isolated DC / DC converters (110, 110') connected to the input (102) and the output (104), respectively.

4. The electrical power system (100) according to claim 3, wherein the two or more galvanic isolated DC / DC converters (110, 110') are connected in series or in parallel at the input (102); and / or the two or more galvanic isolated DC / DC converters (110, 110') are connected in series or in parallel at the output (104).

5. The electrical power system (100) according to any one of the preceding claims, wherein the input (102) comprises a positive terminal capacitor (Ci) and a negative terminal capacitor (C2).

6. The electrical power system (100) according to any one of the preceding claims, wherein the electrical power system (100) comprises: at least one DC / DC converter (130) comprising an input (132) connected to the DC bus (120) and an output (132) connected to a DC power storage unit (210) of the mining / construction vehicle (200).

7. The electrical power system (100) according to claim 6, wherein the DC / DC converter (130) is configured to control a charging / discharging or a power flow of the DC power storage unit (210).

8. The electrical power system (100) according to claim 6 or 7, wherein the DC power storage unit (210) is any of: a battery, a fuel cell and a capacitor.

9. The electrical power system (100) according to any one of the preceding claims, wherein the electrical power system (100) comprises: at least one DC / AC converter (140) comprising an input (142) connected to the DC bus (120) and an output (144) connected to an electrical load (220) of the mining / construction vehicle (200).

10. The electrical power system (100) according to claim 9, wherein the DC / AC converter (140) is a three-phase DC / AC converter.11 . The electrical power system (100) according to claim 9 or 10, wherein the electrical load (220) is any of: a motor, a compressor, and a pump.

12. The electrical power system (100) according to any one of the preceding claims, wherein the electrical power system (100) comprises: an AC / DC converter (150) comprising an input (152) connected to an AC grid (310) and an output (154) connected to the input (102), the AC / DC converter (150) being configured to receive an AC power (AC1 ) from the AC grid (310) and convert the AC power (AC1 ) to the DC input power (DC1 ).

13. The electrical power system (100) according to claim 12, wherein the AC / DC converter (150) is configured to convert the AC power (AC1 ) to the DC input power (DC1 ) with a fixed gain in its sweet spot region.

14. The electrical power system (100) according to claim 12 or 13, wherein the AC / DC converter (150) comprises one or more transformers, one or more filters and one or more rectifiers.

15. The electrical power system (100) according to any one of claims 12 to 14, wherein AC / DC converter (150) is a three-phase AC / DC converter.

16. The electrical power system (100) according to any one of the preceding claims, wherein the DC power source (120) is a DC grid (320).

17. The electrical power system (100) according to any one of the preceding claims, wherein the DC bus (120) comprises a capacitor (CBUS).

18. A mining / construction vehicle (200) comprising: an electrical power system (100) according to any one of the preceding claims, and at least one DC power storage unit (210) and / or an electrical load (220) connected to the DC bus (120).

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