Electrical architecture for battery powered machine

Abstract

An electrical architecture that allows power to be transferred to a battery powered machine while the machine is moving, and allows the machine to be charged while at rest.

Description

Technical Field

[0001] This document generally relates to battery-powered machines and, more particularly, to the architecture of an electrical system for a battery-powered machine. Background Art

[0002] In response to fuel efficiency concerns and desired performance characteristics, emphasis has been placed on using electricity to operate various components associated with a vehicle. Battery-powered machines offer many advantages over combustion engine machines. One advantage is that battery-powered machines do not emit combustion by-products. This advantage is particularly useful in underground mining environments. Combustion engine underground mining machines typically may need to be paired with a ventilation system that provides fresh air to the machine and takes combustion exhaust to the surface.

[0003] One problem faced by battery-powered machines is caused by the different power level requirements of various electrical components. Some applications may require two or more power sources with different power level outputs to meet the needs of the electrical components. Additionally, an electrical bus for separating different power levels and for supplying power to the electrical components may also be necessary.

[0004] U.S. Patent No. 8,761,978 describes a propulsion system that includes an energy system, an auxiliary system, and a system controller. The energy system includes a bidirectional boost converter that is coupled to a direct current (DC) link and includes a plurality of input channels. The energy system also includes a first energy storage device that is coupled via a DC bus to a first input channel of the bidirectional boost converter. The auxiliary system is coupled to the energy system and includes an auxiliary energy source, an auxiliary load, and an auxiliary load controller coupled to the auxiliary energy source and the auxiliary load. The system controller is configured to cause the auxiliary load controller to reduce the power draw of the auxiliary load from the auxiliary energy source and to cause the bidirectional boost converter to boost the voltage supplied by the auxiliary energy source and supply the boosted voltage to the DC link. Summary of the Invention

[0005] This disclosure particularly describes an electrical architecture that allows for power transfer to a battery-powered machine while the machine is in motion and allows the machine to be charged while it is stationary.

[0006] In one aspect, the present disclosure relates to an electrical architecture for a battery-powered machine having at least two different voltage buses, the electrical architecture comprising: a battery module configured to supply a first voltage to a first voltage bus; an AC / DC converter circuit coupled to the first voltage bus and configured to charge the battery module when the battery-powered machine is stationary; a first DC / DC converter circuit coupled between the first voltage bus and a second voltage bus, wherein the first DC / DC converter circuit is configured to generate a second voltage at the second voltage bus, and wherein the second voltage is different from the first voltage; and a second DC / DC converter circuit configured to be coupled between an external power source and the battery module, wherein the second DC / DC converter circuit is configured to receive power from the external power source and charge the battery module when the battery-powered machine is in motion.

[0007] In another aspect, the present disclosure relates to a battery-powered machine comprising an electrical architecture for a battery-powered machine having at least two different voltage buses, the electrical architecture comprising: a battery module configured to supply a first voltage to a first voltage bus; an AC / DC converter circuit coupled to the first voltage bus and configured to charge the battery module when the battery-powered machine is stationary; a first DC / DC converter circuit coupled between the first voltage bus and a second voltage bus, wherein the first DC / DC converter circuit is configured to generate a second voltage at the second voltage bus, and wherein the second voltage is different from the first voltage; and a second DC / DC converter circuit configured to be coupled between an external power source and the battery module, wherein the second DC / DC converter circuit is configured to receive power from the external power source and charge the battery module when the battery-powered machine is in motion.

[0008] In yet another aspect, the present disclosure relates to a method for providing at least two different voltages to a battery-powered machine, the method comprising: supplying a first voltage to a first voltage bus via a battery module; coupling an AC / DC converter circuit to the first voltage bus and charging the battery module while the battery-powered machine is stationary; coupling a first DC / DC converter circuit between the first voltage bus and a second voltage bus; generating a second voltage at the second voltage bus via the first DC / DC converter circuit, wherein the second voltage is different from the first voltage; coupling a second DC / DC converter circuit between an external power source and the battery module; and charging the battery module via the external power source while the battery-powered machine is in motion. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a perspective view of an example of a battery-powered machine in which various techniques of the present disclosure may be implemented.

[0010] Figure 2 is a block diagram of an example of an electrical architecture including two different voltage buses for providing power to a battery-powered machine.

[0011] Figure 3 is a block diagram of an example of an electrical architecture including three different voltage buses for providing power to a battery-powered machine.

[0012] Figure 4 is a flowchart of an example of a method for providing at least two different voltages to a battery-powered machine. DETAILED DESCRIPTION

[0013] Large battery-powered machines, such as mining trucks, require large batteries to provide reasonable runtimes for the machines. Charging these large batteries requires a large amount of power. However, when providing such a large amount of power to charge these large batteries, there may be current-limiting issues. To reduce the current, the voltage can be increased, but this can introduce new requirements imposed by regulations.

[0014] The inventors have recognized a need for an electrical architecture for large battery-powered machines that can achieve high power transfer rates while remaining within component market and regulatory constraints. The present disclosure particularly describes an electrical architecture that allows power to be transferred to a battery-powered machine while the machine is moving and allows the machine to be charged while it is stationary.

[0015] Figure 1FIG. 0 is a perspective view of an example of a battery-powered machine 100 that can implement the various techniques of the present disclosure. Although depicted as a mining truck or a surface haul truck, the battery-powered machine 100 can be any suitable machine, such as any type of loader, bulldozer, dump truck, skid steer loader, excavator, compactor, backhoe, combine harvester, crane, drilling equipment, storage tank, trencher, tractor, any suitable stationary machine, any type of generator, locomotive, marine engine, combinations thereof, etc. The presently disclosed subject matter is not limited to any particular use platform and can be implemented across various types of vehicles, facilities (i.e., non-vehicle use), etc. Figure 1 The battery-powered machine 100 of Figure 1 is for illustrative purposes only.

[0016] As Figure 1 shown in Figure 1 , the battery-powered machine 100 includes a frame 105 and wheels 106. The wheels 106 are mechanically coupled to a drivetrain (not shown) to propel the battery-powered machine 100. When the wheels 106 of the battery-powered machine 100 are rotated, the battery-powered machine 100 traverses the surface 102. Although shown in Figure 1 as having hubs with rubber tires, in other examples, the wheels 106 can alternatively be in the form of drums, chain drives, tracks, combinations thereof, etc. The frame 105 of the battery-powered machine 100 is constructed of any suitable material, such as iron, steel, aluminum, other metals, ceramics, plastics, combinations thereof, etc. The frame 105 has a one-piece construction in some cases and is constructed by joining two or more separate body parts in other cases. The parts of the frame 105 are joined by any suitable variety of mechanisms, including, for example, welding, bolts, screws, other fasteners, epoxy resins, combinations thereof, etc.

[0017] The battery-powered machine 100 can include a hydraulic system 108 that moves a dump box 110 or other movable elements configured to move, lift, carry, and / or dump materials. The dump box 110 is used, for example, to pick up dirt or mined minerals and transport them from one location on the surface 102 to another location on the surface 102. The dump box 110 is actuated by the hydraulic system 108 or any other suitable mechanical system. In some cases, the hydraulic system 108 is powered by an electric motor (not shown), such as by powering one or more hydraulic pumps (not shown) of the hydraulic system 108. It should be noted that in other types of machines (e.g., machines other than mining trucks), the hydraulic system 108 can have a configuration different from the configuration shown herein, can be used to operate elements other than the dump box 110, and / or can be omitted.

[0018] Continuing to refer to Figure 1 ​​, the battery-powered machine 100 also includes an operator station 112. The operator station 112 is configured to seat an operator (not shown) therein. The operator seated in the operator station 112 interacts with various control interfaces and / or actuators within the operator station 112 to control the movement of various components of the battery-powered machine 100 and / or the overall movement of the battery-powered machine 100 itself. Thus, the control interfaces and / or actuators within the operator station 112 allow the propulsion of the battery-powered machine 100 to be controlled by controlling the operation of one or more electric motors 114, which are electric motors and are controlled by a motor controller 116 and powered by a battery 118. The motor controller 116 can be controlled based on operator input received at the operator station 112. A battery controller 120 monitors and controls various aspects of the battery 118, such as controlling the temperature of the battery or preventing over-discharge conditions.

[0019] The electric motor 114 can be of any suitable type, such as an induction motor, a permanent magnet motor, a switched reluctance (SR) motor, a combination thereof, etc. The electric motor 114 has any suitable voltage, current, and / or power rating. When operating together, the electric motors 114 are configured to propel the battery-powered machine 100 as needed for the task to be performed by the battery-powered machine 100. For example, the electric motor 114 can be rated in the range of about 500 volts to about 3000 volts. The motor controller 116 includes one or more control electronics to control the operation of the electric motor 114. In some cases, each electric motor 114 can be controlled by its own motor controller 116. In other cases, all of the electric motors of the battery-powered machine 100 can be controlled by a single motor controller 116. The motor controller 116 can also include one or more inverters or other circuitry to control the energization of the flux generating elements (e.g., coils) of the electric motor 114. The electric motor 114 is mechanically coupled to various drivetrain components (such as drive shafts and / or axles) or directly coupled to the wheels 106 to rotate the wheels 106 and propel the battery-powered machine 100. The drivetrain includes any variety of other components, including but not limited to differentials, (one or more) connectors, constant velocity (CV) joints, etc.

[0020] Although not shown here, there may be one or more electric motors 114 that are not used to propel the battery-powered machine 100 but instead operate a pump and / or other auxiliary components, such as operating the hydraulic system 108. According to an example of the present disclosure, electrical power for energizing the electric motor 114 is received from the battery 118. It should be noted that in some cases, the battery 118 may provide power for operating the electric motor 114 and / or other power-consuming components of the battery-powered machine 100 (e.g., a controller, a cooling system, a display, an actuator, a sensor, etc.). As described above, the presently disclosed subject matter is not limited to using only battery power, as other forms of energy may be used in combination with the power provided by the battery 118, including but not limited to an internal combustion engine or a fuel cell.

[0021] The battery 118 can have any suitable type and capacity. For example, the battery can be a lithium-ion battery, a lead-acid battery, an aluminum-ion battery, a flow battery, a magnesium-ion battery, a potassium-ion battery, a sodium-ion battery, a metal hydride battery, a nickel-metal hydride battery, a cobalt-metal hydride battery, a nickel-cadmium battery, any type of wet cell, any type of dry cell, a gel cell, a combination thereof, etc. The battery 118 can be organized as a collection of electrochemical cells that are arranged to provide the voltage, current, and / or power requirements of the electric motor 114. In some cases, the energy capacity of the battery 118 can be in the range of about 0.2 to about 1.5 relative to the energy available from a full fuel tank 119. In other cases, the energy capacity of the battery 118 can be in the range of about 0.5 to about 1.0 relative to the energy available from a full fuel tank 119 (as would be provided when the battery-powered machine 100 includes a combustion engine such as a reciprocating internal combustion engine or a turbine (not shown)). In still other cases, the energy capacity of the battery 118 can be in the range of about 0.7 to about 0.9 relative to the energy available from a full fuel tank 119. It should be understood that the above ratios are examples, and the present disclosure contemplates ranges outside of the above ranges for the ratio of the energy capacity of the battery 118 to the energy capacity of the fuel tank 119.

[0022] The battery-powered machine 100 includes an engine control module (ECM) 122 that controls various aspects of the battery-powered machine 100. The ECM 122 is configured to receive a battery state (e.g., state of charge (SOC) or other charge-related metric) from a battery controller 120, a fuel level from a fuel tank controller 130, and receive one or more operator signals (e.g., an accelerator signal) that are at least partially based on an operator's interaction with one or more control interfaces and / or actuators of the battery-powered machine 100. In other cases, the ECM 122 may receive control signals from a remote control system via wireless signals received via an antenna 124. The ECM 122 uses the one or more operator signals to generate command signals that control various components of the battery-powered machine 100, regardless of whether the operator signal is received from an operator in the operator station 112 or from a remote controller. For example, the ECM 122 may control the electric motor 114 via a motor controller 116, a hydraulic system 108, and / or control the steering of the battery-powered machine 100 via a steering controller 126. It should be understood that the ECM 122 may control any of the various other subsystems of the battery-powered machine 100 (not explicitly discussed herein) to provide the operating capabilities discussed herein to the battery-powered machine 100.

[0023] Figure 2 is a block diagram of an example of an electrical architecture 200 that includes two different voltage buses for providing power to a battery-powered machine (such as Figure 1 the battery-powered machine 100). The electrical architecture 200 is an Figure 1 example of the electrical architecture 112.

[0024] The electrical architecture 200 includes a rechargeable battery module 202 that includes one or more battery cells 204. The battery module 202 is configured to supply a first voltage V1 to a first voltage bus 206. For example, the battery module 202 may generate a voltage greater than 700 volts (V) (e.g., 750V - 1500V) and supply it to the first voltage bus 206.

[0025] To charge the battery module 202, the electrical architecture 200 may include an AC / DC charger circuit 208, such as a fast charging circuit that can charge the battery module 202 within 20 - 30 minutes. To use the AC / DC charger circuit 208, it is necessary to stop using the battery-powered machine 100. The AC / DC charger circuit 208 is coupled to the first voltage bus 206 via a charging port 210 and is configured to charge the battery module 202 when the battery-powered machine is stationary.

[0026] The electrical architecture 200 includes a number of DC / DC converters. A first DC / DC converter circuit 212 is coupled between a first voltage bus 206 and a second voltage bus 214. The first DC / DC converter circuit 212 is configured to generate a second voltage V2 at the second voltage bus 214, where the second voltage V2 is greater than 500V, such as 550V - 700V. The second voltage V2 is different from the first voltage V1. That is, the nominal voltage V2 (such as 550V - 700V) is different from the nominal voltage V1 (such as 750V - 1500V).

[0027] The second voltage bus 214 can be coupled to and supply power to an accessory system 218 of a battery-powered machine via a power distribution unit (PDU) 216. The accessory system 218 can include one or more of a water pump 220, an electric fan 222, a heating, ventilation, and air conditioning (HVAC) system 224, a DC / DC converter 226 (such as 24V), and a battery thermal management system (BTMS) 228.

[0028] The second voltage bus 214 is also coupled to an electric motor 232 via a DC / AC converter circuit 230. The electric motor 232 is coupled to a hydraulic pump 234, such as coupled to Figure 1 the tipping bucket 102.

[0029] The electrical architecture 200 includes a second DC / DC converter circuit 236 configured to be coupled between an external power source 238 and the battery module 202. The second DC / DC converter circuit 236 is configured to receive power from the external power source 238 and charge the battery module 202 when the battery-powered machine is in motion. The second DC / DC converter circuit 236 is configured to receive a third voltage V3 from the external power source 238. The external power source 238 can also power a traction system 240 to keep the battery-powered machine in motion.

[0030] For example, in some instances, the external power source 238 can be a trolley system that provides power to the electrical architecture 200 via an overhead line or other infrastructure. The external power source 238 can provide a voltage greater than 2500V, such as 2700V - 2800V. The second DC / DC converter circuit 236 can step down the voltage of the external power source 238 to match the voltage V1 of the first voltage bus 206.

[0031] Figure 2 The example shown includes a trolley power box 242 coupled between the external power source 238 and the second DC / DC converter circuit 236. The trolley power box 242 can include sensors and contactors, as well as a reactor for filtering transient interference that may occur when there are multiple machines using the external power source 238.

[0032] The traction system 240 is coupled to the first voltage bus 206 and is configured to receive power from the first voltage bus. The traction system 240 includes two DC / AC converter circuits 244A, 244B that supply power to corresponding motors 246A, 246B. The motors 246A, 246B are coupled to corresponding final drives 248A, 248B, such as two-stage planetary final drives, which in turn are coupled to tires 250A, 250B via corresponding brakes ( Figure 3 as shown).

[0033] Figure 3 is a block diagram of another example of an electrical architecture 300 that includes three different voltage buses for supplying power to a battery-powered machine (such as Figure 1 the battery-powered machine 100). The electrical architecture 300 is an example of the electrical architecture 112 of Figure 1 Many components of the electrical architecture 300 are similar to the components of the electrical architecture 200 of Figure 2 and thus use similar reference numerals. For the sake of brevity, similar components will not be described in detail again.

[0034] Figure 3 The electrical architecture 300 of Figure 2 includes a third voltage bus 302 that is configured to receive a third voltage V3 from an external power source 238. The third voltage V3 is different from both the first voltage V1 and the second voltage V2. That is, the nominal voltage V3 (e.g., 2500V - 2800V) is different from the nominal voltage V1 (e.g., 750V - 1500V) and the nominal voltage V2 (e.g., 550V - 700V). This is in contrast to the electrical architecture 200 of

[0035] Figure 2 which has two voltage buses.The second DC / DC converter circuit 236 is coupled between the third voltage bus 302 and the first voltage bus 206. The traction system 240 of the battery-powered machine is coupled to the third voltage bus 302. This is in contrast to the electrical architecture 200 of

[0036] in which the traction system 240 is coupled to the first voltage bus 206.

[0037] Figure 4Flowchart of an example of a method 400 for providing at least two different voltages to a battery-powered machine. At block 402, method 400 includes supplying a first voltage to a first voltage bus via a battery module. For example, battery module 202 can supply a first voltage V1 to Figure 2 and Figure 3 the first voltage bus 206.

[0038] At block 404, method 400 includes coupling an AC / DC converter circuit to the first voltage bus and charging the battery module when the battery-powered machine is stationary. For example, Figure 2 and Figure 3 the AC / DC charger circuit 208 of can be coupled to the first voltage bus 206 and can charge the battery module 202 when the battery-powered machine (such as Figure 1 the battery-powered machine 100) is stationary.

[0039] At block 406, method 400 includes coupling a first DC / DC converter circuit between the first voltage bus and a second voltage bus. For example, Figure 2 and Figure 3 the first DC / DC converter circuit 212 of can be coupled between the first voltage bus 206 and the second voltage bus 214 to supply power to the accessory system 218.

[0040] At block 408, method 400 includes generating a second voltage at the second voltage bus via the first DC / DC converter circuit, where the second voltage is different from the first voltage. For example, Figure 2 and Figure 3 the first DC / DC converter circuit 212 of can generate a second voltage V2 at the second voltage bus 214, where the nominal first voltage V1 is different from the nominal second voltage V2.

[0041] At block 410, method 400 includes coupling a second DC / DC converter circuit between an external power source and the battery module. For example, Figure 2 and Figure 3 the second DC / DC converter circuit 236 of can be coupled between an external power source 238 (such as a slip power supply system) and the battery module 202.

[0042] At block 412, method 400 includes charging the battery module via the external power source when the battery-powered machine is in motion. For example, the external power source 238 can charge Figure 1 the battery-powered machine 100) when the battery-powered machine (such as Figure 2 and Figure 3 the battery module 202 is in motion.

[0043] Method 400 may optionally include coupling the battery module and the traction system to a first voltage bus.

[0044] Method 400 may optionally include receiving a third voltage from an external power source via a second DC / DC converter circuit 236.

[0045] Method 400 may optionally include receiving a third voltage from an external power source via a third voltage bus, where the third voltage is different from both the first voltage and the second voltage; coupling the traction system of the battery-powered machine to the third voltage bus; and coupling the second DC / DC converter circuit between the third voltage bus and the first voltage bus.

[0046] Method 400 may optionally include coupling the second voltage bus to an accessory system of the battery-powered machine.

[0047] The various coupling and supply operations described above may be performed under the control of one or more machine controllers running appropriate software to execute various commands of an operator.

[0048] Industrial applicability

[0049] Large battery-powered machines, such as mining trucks, require large batteries to provide reasonable runtimes for the machines. Charging these large batteries requires a large amount of power. However, when providing such a large amount of power to charge these large batteries, there may be current-limiting issues. To increase power, the voltage can be increased, but this may encounter regulatory issues.

[0050] The present inventors have recognized a need for an electrical architecture for large battery-powered machines that can achieve high power transfer rates while remaining within component market and regulatory constraints. The present disclosure particularly describes an electrical architecture that allows power to be transferred to a battery-powered machine while the machine is in motion and allows the machine to be charged while it is stationary.

[0051] Unless expressly excluded, the use of the singular to describe a component, structure, or act does not exclude the use of a plurality of such components, structures, or acts or their equivalents. In the context of describing the present invention (especially in the context of the following claims), the use of the terms "a," "an," "the," "at least one," or the term "one or more" and similar referents should be construed to cover both the singular and the plural, unless otherwise specified herein or clearly contradicted by the context. The use of the term "at least one" followed by a list of one or more items (e.g., "at least one of A and B" or one or more of A and B) should be construed to mean either one of the items selected from the listed items (A or B) or any combination of two or more of the listed items (A and B; A, A, and B; A, B, and B), unless otherwise specified herein or clearly contradicted by the context. Similarly, as used herein, the word "or" refers to any possible permutation of a set of items. For example, the phrase "A, B, or C" refers to at least one of A, B, C, or any combination thereof, such as any one of the following: A; B; C; A and B; A and C; B and C; A, B, and C; or a plurality of any items, such as A and A; B, B, and C; A, A, B, C, and C, etc.

[0052] The detailed description above is intended to be illustrative, not restrictive. Accordingly, the scope of the present disclosure should be determined with reference to the appended claims and the full scope of equivalents given by such claims.

Claims

1. An electrical architecture (300)(200) for a battery (118)-powered machine (100) having at least two different voltage buses, the electrical architecture (300)(200) comprising: a battery (118) module (202) configured to supply a first voltage to a first voltage bus (206); an AC / DC converter (226) circuit (236)(212) coupled to the first voltage bus (206) and configured to charge the battery (118) module (202) when the battery (118)-powered machine (100) is stationary; a first DC / DC converter (226) circuit (236)(212) coupled between the first voltage bus (206) and a second voltage bus (214), wherein the first DC / DC converter (226) circuit (236)(212) is configured to generate a second voltage at the second voltage bus (214), and wherein the second voltage is different from the first voltage; and a second DC / DC converter (226) circuit (236)(212) configured to be coupled between an external power source (238) and the battery (118) module (202), wherein the second DC / DC converter (226) circuit (236)(212) is configured to receive power from the external power source (238) and charge the battery (118) module (202) when the battery (118)-powered machine (100) is in motion.

2. The electrical architecture (300)(200) according to claim 1, wherein the battery (118) module (202) and a traction system (224)(240) are coupled to the first voltage bus (206).

3. The electrical architecture (300)(200) according to claim 2, wherein the second DC / DC converter (226) circuit (236)(212) is configured to receive a third voltage from the external power source (238).

4. The electrical architecture (300)(200) according to claim 1, further comprising a third voltage bus (302) configured to receive a third voltage from the external power source (238), wherein the third voltage is different from both the first voltage and the second voltage, wherein a traction system (224)(240) of the battery (118)-powered machine (100) is coupled to the third voltage bus (302), and wherein the second DC / DC converter (226) circuit (236)(212) is coupled between the third voltage bus (302) and the first voltage bus (206).

5. The electrical architecture (300)(200) according to claim 3, wherein the first voltage is greater than 900V, the second voltage is greater than 500V, and the third voltage is greater than 1500V.

6. The electrical architecture (300)(200) according to claim 1, wherein the second voltage bus (214) is configured to be coupled to an accessory system (224)(218) of the battery (118) powered machine (100).

7. The electrical architecture (300)(200) according to claim 6, wherein the accessory system (224)(218) includes one or more of a water pump (220), an electric fan (222), or a heating, ventilation, and air conditioning (HVAC) system (224).

8. A method (400) for providing at least two different voltages to a battery (118) powered machine (100), the method (400) comprising: supplying a first voltage to a first voltage bus (206) via a battery (118) module (202); coupling an AC / DC converter (226) circuit (236)(212) to the first voltage bus (206) and charging the battery (118) module (202) when the battery (118) powered machine (100) is stationary; coupling a first DC / DC converter (226) circuit (236)(212) between the first voltage bus (206) and a second voltage bus (214); generating a second voltage at the second voltage bus (214) via the first DC / DC converter (226) circuit (236)(212), wherein the second voltage is different from the first voltage; coupling a second DC / DC converter (226) circuit (236)(212) between an external power source (238) and the battery (118) module (202); and charging the battery (118) module (202) via the external power source (238) when the battery (118) powered machine (100) is in motion.

9. The method (400) according to claim 8, further comprising: coupling the battery (118) module (202) and a traction system (224)(240) to the first voltage bus (206).

10. The method (400) according to claim 9, further comprising: receiving a third voltage from the external power source (238) via the second DC / DC converter (226) circuit (236)(212).

11. The method (400) according to claim 8, further comprising: receiving a third voltage from the external power source (238) via a third voltage bus (302), wherein the third voltage is different from both the first voltage and the second voltage; coupling a traction system (224)(240) of the battery (118) powered machine (100) to the third voltage bus (302); and coupling the second DC / DC converter (226) circuit (236)(212) between the third voltage bus (302) and the first voltage bus (206).

12. The method (400) according to claim 11, wherein the first voltage is greater than 900V, the second voltage is greater than 500V, and the third voltage is greater than 1500V.

13. The method (400) according to claim 8, further comprising: connecting the second voltage bus (214) to an accessory system (224)(218) of the battery (118) powered machine (100).

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