Reconfigurable Power Processing Unit for Spacecraft Operations

Abstract

A reconfigurable power processing unit for a spacecraft, comprising a plurality of power modules. Each power module includes a first power source and a second power source. The first power source and the second power source are configured to be in series in a first state and in parallel in a second state. A plurality of contactors connect each power module to at least one of another power module among the plurality of power modules and a power processing output, and are configured to control the state of the power module.

Description

Technical Field

[0001] The present invention generally relates to a spacecraft power processing unit, and more particularly to a reconfigurable power processing unit for a spacecraft. Background Art

[0002] Spacecraft (such as satellites and other similarly sized space launch devices) typically include thrusters that are configured to allow the spacecraft to be reoriented or maneuvered. In addition to the thruster(s), the spacecraft will also include one or more on-board systems that require electrical power to operate. The power requirements of the thruster(s) and on-board systems are substantially different, and existing spacecraft utilize different power processing units to supply power to the thrusters and on-board systems.

[0003] The power processing unit required to power the thrusters is large and heavy and is typically not used when the thrusters are not operating. As a result, a significant amount of space and weight on the spacecraft is used to facilitate limited operation and provides minimal utilization outside of those limited operations. Summary of the Invention

[0004] In one exemplary embodiment, a reconfigurable power processing unit for a spacecraft includes: a plurality of power modules, each power module including a first power source and a second power source, wherein the first power source and the second power source are configured to be in series in a first state and in parallel in a second state; and a plurality of contactors that connect each power module to at least one of another power module among the plurality of power modules and a power processing output, and are configured to control the state of the power modules.

[0005] In another example of the above reconfigurable power processing unit for a spacecraft, the plurality of contactors are configured to place a first module among the plurality of power modules in series with a second power module among the plurality of power modules in a first state.

[0006] In another example of any of the above reconfigurable power processing units for a spacecraft, the plurality of contactors are configured to place each first power source in parallel with each other first power source and each second power source in parallel with each other second power source in a second state.

[0007] In another example of any of the above reconfigurable power processing units for a spacecraft, the state of each contactor among the plurality of contactors is controlled via a controller.

[0008] In another example of any of the above reconfigurable power processing units for a spacecraft, the controller includes a memory storing instructions configured to transition the plurality of contactors from a first state to a second state by powering down the power processing unit, changing the state of each of the plurality of contactors, and powering up the power processing unit.

[0009] In another example of any of the above reconfigurable power processing units for a spacecraft, each of the plurality of contactors is one of a mechanical relay, a semiconductor switch, and an electronic logic circuit.

[0010] In another example of any of the above reconfigurable power processing units for a spacecraft, each of the plurality of contactors is a mechanical relay.

[0011] In another example of any of the above reconfigurable power processing units for a spacecraft, the second state is a low voltage power supply state, and wherein the plurality of contactors are configured to normally be in the first state.

[0012] In another example of any of the above reconfigurable power processing units for a spacecraft, the first power source in each of the plurality of power modules is a 150 volt 11 amp power source.

[0013] In another example of any of the above reconfigurable power processing units for a spacecraft, the second state is a 600V, 22A high voltage power supply.

[0014] In another example of any of the above reconfigurable power processing units for a spacecraft, the first state is a 150V, 88A low voltage power supply.

[0015] In another example of any of the above reconfigurable power processing units for a spacecraft, each of the plurality of power modules is the same.

[0016] In another example of any of the above reconfigurable power processing units for a spacecraft, the plurality of power modules includes at least four power modules.

[0017] In another example of any of the above reconfigurable power processing units for a spacecraft, the plurality of power modules includes exactly four power modules.

[0018] An exemplary method for operating a power processing unit includes: providing high-voltage power to a switched power bus for a duration specified by a first load; powering down the power processing unit; transitioning the power processing unit from a first high-voltage supply state to a second low-voltage supply state by switching the state of each of a plurality of contactors; powering up the power processing unit; and providing low-voltage power to the switched power bus.

[0019] In another example of the method for operating a power processing unit described above, the first load is an electric thruster and the duration is the duration of thruster operation.

[0020] In another example of the method for operating a power processing unit described above, providing low-voltage power to the switched power bus includes providing low-voltage power to at least one onboard electrical system of a spacecraft via the switched power bus.

[0021] In an exemplary embodiment, a spacecraft power distribution system includes: a power processing unit configured to provide high-voltage power to a switched power bus in a first state and low-voltage power to the switched power bus in a second state; at least one electric thruster connected to the switched power bus and configured to receive power during the first state; at least one onboard electrical system connected to the switched power bus and configured to receive power during the second state; and a controller configured to control the state of the power processing unit.

[0022] In another example of the spacecraft power distribution system described above, the power processing unit includes: a plurality of power modules, each power module including a first power source and a second power source, wherein the first power source and the second power source are configured to be in series in a first state and in parallel in a second state; and a plurality of contactors connecting each power module to at least one of another power module among the plurality of power modules and a power processing output, and configured to control the state of the power module.

[0023] In another example of any of the spacecraft power distribution systems described above, each of the plurality of power modules is the same.

[0024] These and other features of the present invention can be best understood from the following specification and drawings, which are a brief description of the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Showing a portion of a spacecraft power system including a reconfigurable power processing unit;

[0026] Figure 2 Schematically showing an exemplary reconfigurable power processing unit in a high-voltage configuration;

[0027] Figure 3 Schematically shows a reconfigurable power processing unit in a low voltage configuration; Figure 2 of an exemplary reconfigurable power processing unit;

[0028] Figure 4 Schematically shows Figure 2 and Figure 3 of an exemplary reconfigurable power processing unit that includes relay contactors configured to transform the configuration of the power processing unit;

[0029] Figure 5 Shows a flowchart demonstrating the process for transforming a power processing unit from a first configuration to a second configuration;

[0030] Figure 6 Shows a switched power bus according to an exemplary configuration. DETAILED DESCRIPTION

[0031] Figure 1 Schematically shows a direct current (DC) power system 10 for use in a spacecraft or other space launch vehicle. The power system 10 includes a reconfigurable power processing unit 20 configured to provide power to a switched power bus 30. A plurality of different loads 32, 34 are connected to the switched power bus 30, including one or more electric thrusters 32 and one or more electric on-board systems 34. The state of the power processing unit 20 is controlled via a controller 40. Although shown herein as a single control connection from the controller 40 to the power processing unit 20, it should be understood that any number of corresponding connections may be utilized, such as may be necessary for effecting the reconfigurations described herein.

[0032] The switched power bus 30 is a DC power transfer bus configured to switch which of the connected loads 32, 34 is provided power at any given time. The switched power bus 30 can be any known type of power bus capable of performing power switching and withstanding the voltage and current conditions of high voltage and low voltage loads. Referring Figure 6 , one embodiment of the switched power bus 30 can include switches 501, 503 configured to direct power to either an electric thruster bus 532 or an on-board electric system bus 534. The electric thruster bus 532 provides power to one or more electric thrusters 32, and the on-board electric system bus provides power to one or more on-board electric systems 34.

[0033] The required power characteristics of each load 32, 34 are different, where the thruster 32 requires a high voltage, low current load (e.g., 600V at 22A), and the on-board electronics 34 requires a low voltage load (e.g., 75V - 150V) and can withstand a higher current (e.g., 88A).

[0034] To reduce weight and the area of the spacecraft required to mount the (one or more) power processing units 20, a single reconfigurable power processing unit 20 is capable of providing high voltage, low current power to operate the thruster 32 in one configuration, and capable of providing low voltage, high current power to operate the on-board electronics system 34 in another configuration.

[0035] Continuing to refer Figure 1 , Figure 2 FIG. schematically shows an exemplary reconfigurable power processing unit 100 in a high voltage, low current power output configuration. Also refer Figure 1 , Figure 3 FIG. schematically shows the same exemplary reconfigurable power processing unit 100 in a low voltage, high current power output configuration.

[0036] The exemplary power processing unit 100 includes four modules 110, each module including a pair of power sources 120a, 120b. In one example, each of the power sources 120a, 120b is a 150V, 11A power source. The exemplary modules are substantially the same. As used herein, substantially the same means that the circuits have the same or nearly the same characteristics, taking into account layout variations and manufacturing tolerances.

[0037] To provide a 600V, 22A power output to the switch bus 30, the power sources 120a, 120b in each module 110 are connected in series such that the negative terminal of the first power source 120a is connected to the positive terminal of the second power source 120b. The modules 110 are grouped into two sets of two modules 110, and the modules 110 in a given set are also placed in series. These sets are connected to the output terminals 130 in a parallel configuration. Figure 2 shows the 600V, 22A power output configuration.

[0038] When the thruster 32 is not required, the power processing unit 100 switches to the second configuration, as shown in Figure 3 FIG. In one example, the second configuration is a 150V, 88A power output configuration. To achieve this power output, the power sources 120a, 120b within each module 110 are switched to a parallel configuration, where all the power sources 120a, 120b are directly connected to the power output 130 in such a way that the power sources 120a, 120b are connected in parallel with each other.

[0039] By being configured to operate in both configurations, the power processing unit 100 can provide the correct power levels to thruster 32 and the on-board electrical system 34 according to the specific operating mode of the spacecraft. This in turn reduces the total weight of the spacecraft because a single power processing unit 100 can provide the functionality previously requiring two different power processing units.

[0040] Continuing to refer to Figures 1-3 , Figure 4 FIG. schematically shows a power processing unit 100 including switches 150 for implementing configurability. The power processing unit 100 is illustrated as having Figure 2 switches 150 in a high voltage output configuration. In one example, each switch 150 is a mechanical relay configured to switch from a first connection to a second connection or disconnect when receiving a command signal from the controller 40. In an alternative example, alternative switches 150 may be utilized, including transistor networks or other electronic logic circuits. Each module 110 includes two switches 150 configured to switch the power sources 120a, 120b from a series connection to a parallel connection. Additionally, each of the modules 110 is connected to the output 130 and to another module 110 in the corresponding group via a pair of switches 150 external to the module 110.

[0041] In some examples, the switches 150 may be in a default or normal position in which they are without receiving a control signal. For example, the default position may configure the power processing unit 100 as a low voltage power supply (e.g., Figure 3 ), and the switches 150 switch positions when receiving a signal.

[0042] In an alternative example, the switches 150 may be latching contactors without a default position. In such an example, the switches 150 maintain their current state until receiving a control signal and, when receiving a control signal, switch states. Once switched, the switches 150 maintain their new state until receiving another control signal causing them to switch again.

[0043] Referring to the above Figure 4In terms of the general characteristics, each of the groups A and B of module 110 is the same and is constructed in the following manner. Groups A and B include a first module 110 having a first power source 120a, and the first power source 120a has a positive node and a negative node. The positive node of the first power source 120a is connected to the positive node of the second power source 120b via a first contactor 150a and a positive output node 130+, or is only connected to the positive output node 130+, depending on the state of the first contactor 150a. The negative node of the first power source 120a is connected to the positive node of the second power source 120b, or to the negative output node 130 of the power processing unit 100, depending on the states of a second contactor 150b and a third contactor 150c inside the module 110.

[0044] Similarly, the second module 110 in each of the groups A and B includes a first power source 120a having a positive node and a negative node. The positive node of the first power source 120a is connected to the negative node of the second power source 120b of the first module in groups A and B via a contactor 150c, or is connected to the positive output terminal 130+ of the power processing unit 100 through another contactor 150 outside the module 110 in groups A and B. The negative node of the first power source 120a in the second module 110 is connected to the negative output node 130- of the power processing unit 100, or is connected to the negative node of the second power source 120b and the negative output node 130- in the first module 110 in groups A and B, depending on the state of the contactor 150c.

[0045] Continuing to refer to Figures 1-4 , Figure 5 shows the process for transitioning from Figure 2 's high-voltage configuration to Figure 3 's low-voltage configuration. Initially, the power processing unit 100 is in Figure 2 's configuration, and in the "Provide power to the thruster" step 210, power is provided to the thruster 32. When the spacecraft is repositioned, or when the thruster 32 no longer needs to be activated, the controller determines that power is no longer needed at the thruster 32, and in the "Power off the PPU" step 220, the power processing unit 100 is powered off.

[0046] When the power processing unit 100 is powered off, in the "Reconfigure contacts" step 230, the controller 100 changes the state of each switch 150 to the opposite state. Once all the switches 150 are reconfigured, the controller 40, in the "Power on the PPU" step 240, restarts the power processing unit 100 and provides power to the bus 30. The bus 30 then, in the "Provide power to the on-board systems" step 250, provides power to the connected on-board electrical system 34.

[0047] When power is again needed at the thruster 32, process 200 is reversed to restore to the original contactor state. In either case, the contactor is reconfigured when the power processing unit 100 is in a powered-down state to prevent any unintentional configuration of power to the bus 30.

[0048] Although shown and described above as including exactly four modules 110, one of ordinary skill in the art may expand the reconfigurable system to include additional pairs of power modules depending on the power characteristics required for a given system.

[0049] In Figures 1-6 the example, the controller 40 is an adaptive digital controller that includes a control algorithm that facilitates unique control characteristics for each operating mode. In an alternative example, the control scheme may be accomplished via the implementation of a complex analog controller.

[0050] It should also be understood that any of the above concepts may be used alone or in combination with any or all of the other above concepts. Although embodiments of the present invention have been disclosed, one of ordinary skill in the art should recognize that certain modifications will fall within the scope of the present invention. Accordingly, the appended claims should be studied to determine the true scope and content of the present invention.

Claims

1. A reconfigurable power processing unit for a spacecraft, comprising: a plurality of power modules, each power module of the plurality of power modules including a first power source and a second power source, wherein the first power source and the second power source are configured to be in series in a first state and in parallel in a second state; and a plurality of contactors connecting each power module to at least one of another power module of the plurality of power modules; wherein the state of each contactor of the plurality of contactors is controlled via a controller; wherein when the plurality of power modules are in the first state, the reconfigurable power processing unit provides direct current at a first voltage level, and when the plurality of power modules are in the second state, the reconfigurable power processing unit provides direct current at a lower second voltage level; wherein the controller is configured to transition the plurality of contactors from a first state to a second state by powering down the reconfigurable power processing unit, transitioning the state of each contactor of the plurality of contactors, and powering up the reconfigurable power processing unit; wherein, in the first state, a first power module and a second power module among the plurality of power modules are arranged in series between a first output line and a second output line of the reconfigurable power processing unit, and a third power module and a fourth power module among the plurality of power modules are arranged in series between the first output line and the second output line; and wherein, in the second state, the first power source and the second power source of each power module (i) are connected in parallel with each other, and (ii) are connected in parallel with the first power source and the second power source of all other power modules across a first input line and a second input line.

2. The reconfigurable power processing unit according to claim 1, wherein, The plurality of contactors are configured to place a first module among the plurality of power modules in series with a second power module among the plurality of power modules in the first state.

3. The reconfigurable power processing unit according to claim 1, wherein, The plurality of contactors are configured to place each first power source in parallel with each other first power source and each second power source in parallel with each other second power source in the second state.

4. The reconfigurable power processing unit according to claim 1, wherein, Each contactor of the plurality of contactors is one of a mechanical relay, a semiconductor switch, and an electronic logic circuit.

5. The reconfigurable power processing unit according to claim 1, wherein, The second state is a low voltage power supply state, and wherein the plurality of contactors are configured to normally be in the first state.

6. The reconfigurable power processing unit according to claim 1, wherein The first power source in each power module of the plurality of power modules is a 150 V, 11 A power source.

7. The reconfigurable power processing unit according to claim 6, wherein, The second state is a 600V, 22A high voltage power supply.

8. The reconfigurable power processing unit according to claim 6, wherein, The first state is a 150V, 88A low voltage power supply.

9. The reconfigurable power processing unit according to claim 1, wherein, Each power module of the plurality of power modules is the same.

10. The reconfigurable power processing unit according to claim 1, wherein, The plurality of power modules includes at least four power modules.

11. The reconfigurable power processing unit according to claim 10, wherein, The plurality of power modules includes exactly four power modules.

12. A method for operating a power processing unit, comprising: placing the power processing unit in a first state, in which the power processing unit provides high voltage direct current to a switched power bus for a duration specified by a first load; powering down the power processing unit; The power processing unit is transitioned from a first state to a second state by switching the state of each of a plurality of contactors, wherein the power processing unit supplies a low voltage DC to the switched power bus when in the second state; Power up the power processing unit; And Supply a low voltage DC to the switched power bus; Wherein, in the first state, a first power module and a second power module among the plurality of power modules are arranged in series between a first output line and a second output line of the power processing unit, and a third power module and a fourth power module among the plurality of power modules are arranged in series between the first output line and the second output line; and Wherein, in the second state, the first power source and the second power source of each of the power modules (i) are connected in parallel with each other, and (ii) are connected in parallel with the first power source and the second power source of all other power modules across a first input line and a second input line.

13. The method according to claim 12, wherein, The first load is an electric thruster, and the duration is the duration of thruster operation.

14. The method according to claim 12, wherein, Supplying a low voltage DC to the switched power bus includes supplying a low voltage DC to at least one on-board electrical system of the spacecraft through the switched power bus.

15. A spacecraft power distribution system, comprising: A power processing unit configured to supply high voltage power to a switched power bus in a first state and supply low voltage power to the switched power bus in a second state; At least one electric thruster connected to the switched power bus and configured to receive power during the first state; At least one on-board electrical system connected to the switched power bus and configured to receive power during the second state: and A controller configured to control the state of the power processing unit; Wherein the power processing unit includes a plurality of power modules, and each power module among the plurality of power modules includes a first power source and a second power source, and the first power source and the second power source are configured to be connected in series with each other in the first state and connected in parallel with each other in the second state; Wherein the controller is configured to transition the power processing unit from the first state to the second state by powering down the power processing unit, transitioning the power processing unit from the first state to the second state, and repowering the power processing unit; Wherein, in the first state, a first power module and a second power module among the plurality of power modules are arranged in series between a first output line and a second output line of the power processing unit, and a third power module and a fourth power module among the plurality of power modules are arranged in series between the first output line and the second output line; and Wherein, in the second state, the first power source and the second power source of each of the power modules (i) are connected in parallel with each other, and (ii) are connected in parallel with the first power source and the second power source of all other power modules across a first input line and a second input line.

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