Embodiments of the present invention relate to systems and methods for managing regenerated energy harvested during operation of machinery, devices, or systems performing a predictable work cycle, such as shovels or excavators used in mining environments.
Mining shovels, such as electric rope or power shovels, are used to remove material from, for example, a bank of a mine. An operator controls a shovel during a dig operation to load a dipper with materials. The operator deposits the materials contained in the dipper at a dumping location, such as into a haul truck, into a mobile crusher, onto an area on the ground, onto a conveyor, etc. After unloading the materials, the dig cycle continues and the operator swings the dipper back to the bank to perform additional digging.
During operation, the work cycle of a shovel is repetitive. For example, a shovel's work cycle typically includes a dig segment, a swing segment, a dump segment, and a return segment. These segments are repeated with minor variations (e.g., due to digging conditions). Therefore, work cycle segments of a shovel are predictable, and work cycle decomposition algorithms have been developed and incorporated into heavy equipment controllers for providing semi-autonomous control, machine monitoring, and operator performance monitoring. The algorithms can determine work cycle segments based on motion, position, speed, torque, etc. of the shovel, or, more particularly, the dipper.
Accordingly, embodiments of invention use the predictability of work cycle segments to efficiently harvest energy during regenerative portions of a work cycle and improve machine energy usage (i.e., minimize fuel consumption). In particular, one embodiment of the invention provides an industrial machine that includes at least one controller. The controller is configured to (1) detect an occurrence of a regenerative work cycle segment within a repetitive work cycle including a plurality of work cycle segments performed by the industrial machine and (2) modify operation of at least one power source included in the industrial machine for the regenerative work cycle segment.
Another embodiment of the invention provides a method of operating an industrial machine. The method includes detecting, by a controller, an occurrence of a regenerative work cycle segment within a repetitive work cycle performed by the industrial machine, the repetitive work cycle including a plurality of work cycle segments. The method also includes modifying, by the controller, operation of the industrial machine for the regenerative work cycle.
Yet another embodiment of the invention provides an energy management system. The energy management system includes a bi-directional power bus and a power conversion unit that receives electrical power from the bi-directional power bus and generates regulated electrical energy. The system also includes an actuator that receives regulated electrical energy from the power conversion unit to operate at least one tool within a repetitive work cycle having a plurality of work cycle segments. The system further includes an engine and a motor-generator coupled to and driven by the engine. The motor/generator generates electrical energy and supplies the electrical power to the bi-directional power bus. In addition, the system includes a controller configured to (1) detecting an occurrence of one of the plurality of work cycle segments during which regenerative power is generated and (2) modify operation of at least one of the engine and the bi-directional power bus for the work cycle segment based on the regenerative power.
Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of or quantity of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways.
Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limited. The use of “including,” “comprising” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms “mounted,” “connected” and “coupled” are used broadly and encompass both direct and indirect mounting, connecting and coupling. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings, and can include electrical connections or couplings, whether direct or indirect. Also, electronic communications and notifications may be performed using any known means including direct connections, wireless connections, etc.
It should also be noted that a plurality of hardware and software based devices, as well as a plurality of different structural components may be used to implement the invention. In addition, it should be understood that embodiments of the invention may include hardware, software, and electronic components or modules that, for purposes of discussion, may be illustrated and described as if the majority of the components were implemented solely in hardware. However, one of ordinary skill in the art, and based on a reading of this detailed description, would recognize that, in at least one embodiment, the electronic based aspects of the invention may be implemented in software (e.g., stored on non-transitory computer-readable medium) executable by one or more processing units, such as a microprocessor and/or an application specific integrated circuits (“ASICs”). As such, it should be noted that a plurality of hardware and software based devices, as well as a plurality of different structural components may be utilized to implement the invention. Furthermore, and as described in subsequent paragraphs, the specific mechanical configurations illustrated in the drawings are intended to exemplify embodiments of the invention and that other alternative mechanical configurations are possible. For example, “controllers” described in the specification can include standard processing components, such as one or more processing units, one or more computer-readable medium modules, one or more input/output interfaces, and various connections (e.g., a system bus) connecting the components.
As also illustrated in
The shovel 100 includes one or more “actuators” for driving or operating one or more “tools.” The “actuators” can include electric or hydraulic motors. The “tools” can include various components included in the shovel 100, such as the winches for operating the cables 150 or the handle 135, a mechanism for operating the door 145 (e.g., the cable 160), a mechanism for operating a clamshell design of the dipper 140, mechanisms for swinging the base 110, and mechanisms for operating the tracks 105.
For example,
The engine 202 is also mechanically coupled to a motor-generator 204. The motor-generator 204 is driven by the engine 202 to generate electrical energy. The motor-generator 204 outputs the generated electrical energy to a bi-directional power bus 206. Power conversion units (“PCUs”) 208 are also coupled to the bus 206. The PCUs 208 convert the electrical energy available on the bus 206 into regulated electrical energy usable by an actuator (e.g., an electric motor). For example, the PCUs 208 can convert electrical energy available on the bus 206 from a first voltage to a second voltage.
As illustrated in
As described above in the summary section, an operator operates the shovel 100 to perform a repetitive work cycle that includes a plurality of work cycle segments. The work cycle segments can include a dig segment (“DIG”), a swing segment (“S”), a dump segment (“DUMP”), and a return segment (“R”). In a dig segment, the operator raises the dipper 140 while the dipper 140 is engaged in a bank of material to load material into the dipper 140. Next, in the swing segment, the operator swings the loaded dipper 140, which disengages the dipper 140 from the bank and moves the dipper 140 toward a dumping location, such as a haul truck 175. In the dump segment, with the dipper 140 positioned over the dumping location (e.g., the bed 176 of the haul truck 175), the operator opens the door 145 of the dipper 140 (e.g., using the handle 135) or opens the clamshell bucket of the dipper 140 and dumps the material from the dipper 140 into the dumping location. In the return segment, the operator lowers the dipper 140 to the bank floor to begin another cycle. The operator repeats these segments of the work cycle with minor variations (e.g., based on digging conditions).
As also illustrated in
Furthermore, given the predictability of the work cycle segments included in the repetitive work cycle, energy generated and consumed by the shovel 100 can be efficiently managed. For example, as illustrated in
The processing unit 350 retrieves and executes instructions and data stored in the computer-readable modules 355. The processing unit 350 also stores data to the computer-readable modules 355 as part of executing instructions. The computer-readable modules 355 includes non-transitory computer readable medium and includes volatile memory, non-volatile memory (e.g., flash memory), or a combination thereof. The input/output interface 365 receives information from devices and systems external to the controller 300 and outputs information to devices and systems external to the controller 300. For example, the input/output interface 365 communicates with the engine 202, the generator 204, and/or one or more of the PCUs 208 using one or more wired or wireless connections. In some embodiments, the input/output interface 365 also stores data received from devices and systems external to the controller 300 to the computer-readable modules 355 and/or retrieves data from the modules 355 to output to the external devices and systems.
As illustrated in
As illustrated in
The instructions stored in the computer-readable memory modules 355 perform particular functionality when executed by the processing unit 350. For example, the controller 300 executes instructions to perform various energy management methods. In particular, as described in more detail below, the controller 300 executes instructions detect a regenerative work cycle segment performed by the shovel 100 and manage the shovel 100 (e.g., the engine 202, the generator 204, and/or the bus 206) to efficiently provide and consume energy during the identified segment. As used in the present application, the controller 300 “detects” a regenerative work cycle segment by identifying that the current work cycle segment is a regenerative work cycle segment or by predicting that a future (e.g., subsequent) work cycle segment is a regenerative work cycle segment.
For example,
After determining the current work cycle segment, the controller 300 identifies whether the current work cycle segment is a regenerative work cycle segment (e.g., using a look-up table or other data stored in the modules 355). Alternatively or in addition, the controller 300 (1) determines a subsequent work cycle segment (e.g., the next work cycle segment) based on the current work cycle segment and the sequence of work cycle segments included in the repetitive work cycle and (2) identifies whether the subsequent work cycle segment is a regenerative work cycle segment. When the controller 300 determines that the current and/or subsequent work cycle segment is a regenerative work cycle segment, the controller 300 modifies operation of the shovel 100 to increase energy efficiency (at block 402).
For example, in some embodiments, the controller 300 modifies the shovel 100 by using regenerative energy to increase the speed of the engine 202 above the nominal operating speed. In particular, the generator 204 can use regenerative energy supplied over the bus 206 to drive or assist mechanical components of the engine 202 and other components mechanically coupled to the engine 202, such as the pump drive transmission 200. Since energy is a function of the square of the change in rotational speed, the increased engine speed results in increased energy storage or availability. Augmenting inertia to the engine 202 and/or the pump drive transmission 200, such as with a flywheel, also allows for further increased energy storage as rotating inertia. Additional power train inertia can also be used to compensate for engine control fluctuations during dynamic portions of a work cycle. Stored rotational energy can then be consumed during non-regenerative work cycle segments, which improves machine efficiency. In addition, the increased energy storage capacity resulting from the increased engine speed can reduce or eliminate the need for energy storage devices, such as ultra-capacitors or batteries, which reduces machine cost and weight and improves reliability.
Additionally or alternatively, the controller 300 can modify the operation of the shovel 100 by commanding an engine speed reference lower than the nominal operating speed of the engine 202 in anticipation of a regenerative work cycle segment. When the engine 202 uses a closed-loop speed control scheme, a lower engine speed reference causes the engine 202 to decrease fuel intake (e.g., controlled by an engine controller) until the lower speed reference is achieved. Commanding a lower engine speed prior to the start of a regenerative work cycle segment allows for a greater change in rotational drive line speed when driving or assisting driving the engine 202 and other mechanically-coupled loads with regenerative energy. Therefore, lowering the nominal operating speed allows for increased energy storage or availability, and the stored rotational energy can be consumed during non-regenerative work cycle segments, which improves machine efficiency. Also, the increased energy storage capacity resulting from a lowered engine speed reference can reduce or eliminate the need for energy storage devices, such as ultra-capacitors or batteries, which reduces machine cost and weight and improves reliability.
Additionally or alternatively, the controller 300 can modify the operation of the shovel 100 by reducing the bus voltage in anticipation of a regenerative work cycle segment. The reduced bus voltage commanded by the controller 300 improves overall energy storage capability because of a larger allowable change in bus voltage. Increased stored energy will also be achieved because a greater change in bus voltage will be allowed during the regenerative work cycle segment. The stored energy can be consumed in non-regenerative work cycle segments, which improves machine energy efficiency. Energy storage can also be augmented by coupling additional storage devices, such as ultra-capacitors or batteries, to the bus 206. However, the increased energy storage capacity that results from reducing the bus voltage can reduce or eliminate the need for energy storage devices, such as ultra-capacitors or batteries, which reduces machine cost and weight and improves reliability.
Thus, embodiments of the invention provide, among other things, energy management systems and methods for industrial equipment, such as equipment used for mining and construction environments. However, it should be understood that the energy management systems and methods described herein can be used with any device or system having predictable work or duty cycles. Therefore, the specifics of the shovel 100 described in the present document do not limit the scope of the present invention, and the described energy management systems and methods can be used with other types of shovels, other mining machinery, other industrial machinery, and other non-industrial machinery. For example, manufacturing and assembly machinery, transit systems (e.g., rail and/or tram systems), and other systems having a repetitive and predictable operational cycle or sequence can use the energy management systems and methods described herein.
Furthermore, it should be understood that the controller 300 can be configured to modify operation of the shovel 100 for a regenerative work cycle segment prior to the start of and/or during any portion of a regenerative work cycle segment. In particular, as used in the present application, modifying operation “for” a regenerative work cycle segments includes modifying operation prior to the start and/or during any portion of the segment. For example, in some embodiments, the controller 300 is configured to modify operation of the shovel 100 approximately immediately after detecting the occurrence of a current or subsequent regenerative work cycle segment. The controller 300 can also be configured to perform the modification prior to the start of a regenerative work cycle segment and, in some, embodiments, maintains the modification for the duration of the regenerative work cycle segment. During or after the regenerative work cycle segment, the controller 300 can be configured to undo the modification (e.g., return the engine 202 to a normal or non-modified operating speed and/or return the power bus 206 to a normal or non-modified operating voltage—e.g., the operating speed and/or operating voltage used prior to the modification). For example, the controller 300 can be configured to detect the end of a regenerative work cycle segment (e.g., by detecting the start of a subsequent non-regenerative work cycle segment) and return the shovel 100 to non-modified operating conditions before, at, or after the end of the regenerative work cycle segment.
It should also be understood that the above energy management methods can be combined in various configurations. For example, in some embodiments, the controller 300 is configured to modify the voltage of the bus 206 but not modify operation of the engine 202 or vice versa prior to and/or during the regenerative work cycle segment. Also, in some embodiments, the controller 300 is configured to perform different modifications during different portions of a regenerative work cycle segment (e.g., modify the bus 206 prior to the start of the regenerative work cycle segment or during a first portion of a regenerative work cycle segment and modify the engine 202 during a second portion of the regenerative work cycle segment). The desired modifications or combinations can depend on the machinery, device, or system being controlled and/or the associated operating environment. In addition, it should be understood that power supplied by the generators can be directed to other components of the shovel 100 (such as alternators or compressors) than those described herein.
Various features and advantages of the invention are set forth in the following claims.
The present application claims priority to U.S. Provisional Application No. 61/703,879 filed Sep. 21, 2012, the entire contents of which is incorporated by reference herein.
Number | Date | Country | |
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61703879 | Sep 2012 | US |