Patent Publication Number: US-2020282486-A1

Title: Inverter-based generator and welding system

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation patent application of U.S. Non-Provisional application Ser. No. 15/935,674, entitled “Inverter-Based Generator And Welding System,” filed Mar. 26, 2018, which is a Continuation patent application of U.S. Non-Provisional application Ser. No. 14/229,353, entitled “Inverter-Based Generator And Welding System,” filed Mar. 28, 2014, both of which are herein incorporated by reference in their entirety for all purposes. 
    
    
     BACKGROUND 
     The invention relates generally to welding systems and, more particularly, to inverter-based welding systems. 
     Welding is a process that has become increasingly ubiquitous in various industries and applications. As such, a variety of welding applications, such as construction and shipbuilding, may require welding devices that are portable and can easily be transported to a remote welding location. Accordingly, in some cases, it is often desirable for such welding devices to be operable as standalone units remote from a power grid or other primary power source. Therefore, a variety of welding systems utilizing alternate power sources, such as small gasoline-fueled engines, have been developed. However, certain welding tasks such as welding performed off-road or remotely to quickly repair certain equipment and/or other machinery, for example, may include load demands that are very small as compared to other larger welding tasks. It may be useful to provide a more compact and efficient portable welding system. 
     BRIEF DESCRIPTION 
     In one embodiment, a system includes an engine configured to drive a generator to produce a first power output, and a first inverter communicatively coupled to the generator. The first inverter is configured to convert the first power output into a second power output. The system includes a second inverter communicatively coupled to the generator. The second inverter is configured to convert the first power output into a third power output. The third power output includes a welding power output. 
     In a second embodiment, a welding power supply unit includes an engine configured to drive a generator to produce a first power output, and a first inverter communicatively coupled to the generator. The first inverter is configured to convert the first power output into a second power output. The welding power supply unit includes a second inverter communicatively coupled to the generator. The second inverter is configured to convert the first power output into a welding power output. The welding power supply unit includes a welding torch detachably coupled to the welding power supply unit and configured to receive the welding power output. 
     In a third embodiment, a welding system includes an enclosure. The enclosure includes an engine configured to drive a generator to produce a first power output, and a plurality of inverters communicatively coupled to the generator. The plurality of inverters is configured to convert the first power output into a second power output and a third power output concurrently. The third power output includes a welding power output. 
    
    
     
       DRAWINGS 
       These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein: 
         FIG. 1  is a perspective view of an inverter-based power supply unit, which functions to power, control, and provide consumables to a welding operation and/or auxiliary equipment; 
         FIG. 2  is a schematic diagram of the inverter-based power supply unit of  FIG. 1  including a welding circuit, in accordance with present embodiments; and 
         FIG. 3  is a series of plots illustrating the power conversion techniques and outputs of the inverter-based power supply unit of  FIG. 1 , in accordance with present embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Present embodiments relate to an inverter-based generator and welding system. In certain embodiments, the inverter-based generator and welding system may be useful in permitting the system to be moved from place to place relatively easily, or may be designed as a generally stationary system. Moreover, the inverter-based generator and welding system may be designed for field operation, in which case it may include an engine-generator unit within the enclosure that provides the necessary power for a given welding operation. Thus, the inverter-based generator and welding system may be designed for use in various applications and locations (e.g., remote locations, locations away from typical work areas or workstations, off-road locations, and so forth) in which one or more sources of utility power may be at least temporarily inaccessible. Furthermore, in certain embodiments, the inverter-based generator and welding system may be configured to operate as a standalone generator, a standalone welder, or concurrently as a standalone generator and as a standalone welder. In this manner, the inverter-based generator and welding system may provide an operator with the advantage of having sufficient power for auxiliary equipment (e.g., lighting at a campsite or other off-road worksite) as well as sufficient power to perform one or more welding operations (e.g., at the campsite or the off-road worksite). 
     With the foregoing in mind, an embodiment of a generator and welding system, such as an inverter-based generator and welding system  10 , is illustrated in  FIG. 1 . The inverter-based welding system  10  may provide power and control for a welding operation and/or auxiliary equipment. The inverter-based welding system  10  may include a power supply unit  12  enclosed in a cabinet or enclosure  14 . As previously noted, in certain embodiments, the inverter-based welding system  10  may be useful in enabling the power supply unit  12  to be moved from place to place relatively easily, or may be designed as a generally stationary system. Moreover, the inverter-based welding system  10  may be designed for field operation, in which case it may include, for example, one or more of an engine-generator unit, a fuel cell, and an energy storage device within the enclosure  14  that provide the necessary power for a given welding operation or other application. In certain embodiments, the inverter-based welding system  10  may be designed for use in various locations (e.g., remote locations, locations away from typical work areas or workstations, off-road locations, and so forth) in which one or more sources of utility power may be at least temporarily inaccessible. Thus, the power supply unit  12  may operate as a standalone unit, generating the power necessary for a welding operation and/or auxiliary operations while isolated from additional power sources. 
     As further illustrated by  FIG. 1 , the power supply unit  12  may include a control panel  16 , through which an operator may, for example, control the machine operational characteristics, such as power, weld output, and so forth, for a welding operation via dials and switches  18 . The control panel  16  may also include an auxiliary power output receptacle  20  and welding power output connectors  21  for outputting alternating current (AC) and/or direct current (DC) output power, respectively. As the operator adjusts operating parameters via the control panel  16 , signals may be generated and received by one or more control circuits that may be included within the power supply unit  12 . The power supply unit  12  controller may implement the desired welding operation in accordance with these inputs. For example, in one embodiment, the controller may implement a constant current regime for use with a shielded metal arc welding (SMAW) or stick welding operation and/or process type. 
     In certain embodiments, an electrode assembly  22  may extend from the welding power output connectors  21  of the power supply unit  12  to the location of the weld. A first cable  24  and a welding torch  26  may be coupled to the power supply unit  12  as components of the electrode assembly  22 . The welding torch  26  may be used to secure a welding electrode suitable for shielded metal arc welding (SMAW) (e.g., stick welding) operations. A work assembly  28  extending from the welding power output connectors  21  of the power supply unit  12  to the weld includes a second cable  30  terminating in a work lead clamp  32 . During, for example, a weld operation, the work lead clamp  32  may be coupled to a workpiece  34  to create a circuit between the welding torch  26 , the workpiece  34 , and the power supply unit  12 . That is, as the welding operator, for example, contacts or closely approaches the tip of the electrode of the welding torch  26  to the workpiece  34 , an electrical circuit is completed through the cables  24  and  30 , the welding torch  26 , the workpiece  34 , and the work lead clamp  32  to generate an electrical arc between the electrode tip and the workpiece  34  to perform a weld of the workpiece  34 . 
     In certain embodiments, as further illustrated by  FIG. 1 , a detachable (e.g., removable) receptacle  36  may be included as part of the power supply unit  12 . The detachable receptacle  36  may be useful in storing one or more components of the inverter-based welding system  10 . For example, the detachable receptacle  36  may be a pouch, a tote, or similar receptacle that may couple to an exterior portion of the power supply unit  12 . As the inverter-based welding system  10  may be used as a portable (e.g., capable of being hand-carried by a single operator or transported from place to place by a single operator) generator and/or welding generator, the detachable receptacle  36  may be provided to facilitate the portability of the inverter-based welding system  10 . For example, the detachable receptacle  36  may be used by an operator of the inverter-based welding system  10  to package or store one or more components (e.g., the cable  24 , the welding torch  26 , and so forth) of the electrode assembly  22  and/or components (e.g., the cable  30 , the work lead clamp  32 , and so forth) of the work assembly  28 . 
       FIG. 2  illustrates a schematic embodiment of the inverter-based power supply unit  12  of  FIG. 1 . As illustrated, the inverter-based power supply unit  12  may include an engine  38 , a generator  40 , a DC bus  42 , inverters  43  and  44 , a step-down and/or isolation transformer  46 , output circuits  47  and  48 , and control circuitry  50  all enclosed within the single enclosure  14 . In certain embodiments, the inverter-based power supply unit  12  may be used to generate commanded power output levels for an auxiliary operation and/or welding operation, as described in detail below. Such commanded power output levels may be commanded based on one or more of amperage, voltage, wire type, wire feed speed, electrode diameter, and so forth. As such, the engine  38  may be used to drive the generator  40  to produce power (e.g., electrical power), which may be utilized to provide an auxiliary power output  52  (e.g., AC electrical output), to power an additional device or other auxiliary equipment (e.g., lights, grinding equipment, cutting tools, and so forth) and/or to produce a welding power output  54  (e.g., DC electrical output). 
     The engine  38  may include a fuel source useful in providing power to the generator  40 . The engine  38  may include a combustion engine powered by gasoline, diesel, LP fuel, natural gas, or other fuels, and may be configured to drive one or more rotating drive shafts. For example, in one embodiment, the engine  38  may include an industrial gas/diesel engine having a power rating of below approximately 15 hp, below approximately 10 hp, or below approximately 5 hp. Thus, at the aforementioned power ratings and physical size, the engine  38  may be referred to as a small industrial engine. The generator  40  coupled to the engine  38  may convert the power output (e.g., mechanical energy) of the engine  38  into electrical power, producing an alternating current (AC) voltage output. In certain embodiments, the generator  40  may be rated at less than approximately 1000 watts (W), less than approximately 2000 W, less than approximately 3000 W, less than approximately 4000 W, or otherwise up to approximately 5000 W. 
     As previously noted, the power supply unit  12  may include the DC bus  42  and the inverters  43  and  44 . The DC bus  42  may include a bridge rectifier  56  connected to a bus capacitance  58  (Cbus). In certain embodiments, the bridge rectifier  56  may include a configuration (e.g., an H-bridge configuration) of diodes (e.g., D 1 , D 2 , D 3 , and D 4 ) for converting (e.g., rectifying) the incoming AC voltage signal (e.g., 115V, 120V, 200V, 208V, 230V, or similar voltage rating) generated via the generator  40  into a filtered direct current (DC) voltage signal. If a low AC voltage is supplied by the generator  40 , a boost circuit could be incorporated into the DC bus  42  to raise the voltage to the desired operational level. The rectified and filtered DC voltage signal may then be transmitted to power switches  60  (e.g., semiconductor switches Q 1 , Q 2 , Q 3 , Q 4 ) of the auxiliary inverter  43  or to power switches  62  (e.g., semiconductor switches Q 5 , Q 6 , Q 7 , Q 8 ) of the welding power inverter  44  to respectively produce the AC auxiliary power output  52  and the DC welding power output  54 . 
     Specifically, the power switches  60  (e.g., switches Q 1 , Q 2 , Q 3 , Q 4 ) may convert the rectified and filtered DC voltage signal into an AC voltage signal, which may be then filtered via an inductor  64  and capacitor  66  of the output circuit  47  to produce a constant AC auxiliary power output  52 . It should be appreciated that the power switches  60  and  62  may include any configuration of integrated power electronic switching devices such as insulated gate bipolar transistors (IGBTs), field-effect transistors (FETs), and so forth, which may be controlled (e.g., by the control circuitry  50 ) to switch from “ON” (e.g., activated) and “OFF” (e.g., deactivated) states to control the power conversion via the inverter  43  and/or inverter  44 , and by extension, the AC auxiliary power output  52  and the DC welding power output  54 . 
     For example, in a similar manner, the power switches  62  (e.g., switches Q 5 , Q 6 , Q 7 , Q 8 ) may convert the rectified and filtered DC voltage signal into an AC voltage signal, which may be then reduced (e.g., stepped down) via a step-down and/or isolation transformer  46  to a voltage level (e.g., approximately 70 VAC, or other similar voltage rating) suitable for producing a welding power output. The transformer  46  may be any device capable of reducing the AC voltage signal produced, for example, by the power switches  62  of the inverter  44  to a voltage level suitable for producing a welding power output to supply to the welding torch  26 . The transformer  46  may also be used to isolate the welding-specific circuitry of the inverter-based power supply unit  12  from the AC auxiliary power output  52  circuitry of the power supply unit  12 . The output circuit  48  may then convert the welding-level AC voltage signal received from the transformer  46  back into a DC voltage signal via an output rectifier  68 . The new DC voltage signal may be then useful for supporting various welding operations and/or processes (e.g., a SMAW welding process). 
     Although not illustrated, as previously noted, it should be appreciated that the AC auxiliary power output  52  may be used to power another external device and/or other auxiliary equipment. For example, the inverter-based power supply unit  12  may supply the voltage AC auxiliary power output  52  to external lighting equipment, grinding equipment, cutting tools, and so forth. Likewise, as noted above, the inverter-based power supply unit  12  may also be used to generate a welding power output, for example, to perform one or more welding operations. Furthermore, by providing the inverters  43  and  44  in conjunction with the engine  38  and generator  40 , the inverter-based power supply unit  12  may operate markedly quieter than other generator and/or welding systems. 
     In certain embodiments, as further illustrated by  FIG. 2 , the engine  38 , the generator  40 , the DC bus  42 , and the inverters  43  and  44  may each be controlled and/or commanded by the control circuitry  50 . The control circuitry  50  may include an analog control circuit, or it may include a processor  70  and/or other data processing circuitry that may be communicatively coupled to a memory  72  to execute instructions to control, for example, one or more parameters of the engine  38 , the generator  40 , and the bridge rectifier  56 , and the power switches  60  and  62  of the respective inverters  43  and  44 . These instructions may be encoded in programs or code stored in tangible non-transitory computer-readable medium, such as the memory  72  and/or other storage. The processor  70  may be a general purpose processor, system-on-chip (SoC) device, application-specific integrated circuit (ASIC), or other processor configuration. Similarly, the memory  72  may include, for example, random-access memory (RAM), read-only memory (ROM), flash memory (e.g., NAND), and so forth. 
     In one embodiment, the control circuitry  50  may be useful in controlling the power switches  60  and  62  of the respective inverters  43  and  44 , or other components of the inverter-based power supply unit  12  to produce a stabilized AC power output (e.g., AC auxiliary power output  52 ) to power auxiliary equipment and/or a stabilized DC welding power output to support one or more welding operations and/or processes. For example, the inverter-based power supply unit  12  may be used to support a stick (SMAW) welding process, which may generally use a constant current (CC) welding power output controlled by the control circuitry  50 . In such an embodiment, the control circuitry  50  may control the amperage output (e.g., amperage of an electrical arc generated via the welding torch  26 ) to a predetermined CC value by adjusting voltage and/or amperage feedback signals detected at the output stage of the inverter  44 . In other embodiments, the inverter-based power supply unit  12  may be used to perform other user-selected welding processes, such as a flux cored welding process, a metal inert gas (MIG) welding process, and the like. 
     In certain embodiments, the welding power output  54  may be generated in place of, in addition to, or concurrently (e.g., at the same time) with the AC auxiliary power output  52 . That is, the power supply unit  12  may produce the AC auxiliary power output  52  and the DC welding power output  54  substantially simultaneously (e.g., occurring at substantially the same time) and/or concurrently (e.g., occurring in parallel or at substantially the same time). For example, during operation, if the power supply unit  12  is operating at an output power rating of, for example, approximately 3000 W, the power supply unit  12  may provide 3000 W of power as the AC auxiliary power output  52 , 3000 W of power as the DC welding power output  54 , or concurrently provide 1500 W for each of the AC auxiliary power output  52  and the DC welding power output  54  at substantially the same time. 
     Nevertheless, it should be appreciated that the power provided as the respective power outputs  52  and  54  may be dependent upon the specific auxiliary equipment receiving the power output  52  and/or the specific welding operation or task being performed via the power output  54 . Thus, when the power supply unit  12  supplies the power outputs  52  and  54  concurrently, the total power output (e.g., 1000 W, 2000 W, 3000 W, 3500 W, and so forth) may or may not be divided evenly between the respective power outputs  52  and  54 . Furthermore, as the present embodiments of the inverter-based power supply unit  12  may be designed for use in various locations (e.g., remote locations, locations away from typical work areas or stations, off-road locations, and so forth), having the ability to operate as a standalone generator, a standalone welder, or concurrently as a standalone generator and as a standalone welder may allow an operator the advantage of having sufficient power for auxiliary equipment (e.g., lighting at a campsite or other off-road worksite) as well as sufficient power to perform one or more welding operations (e.g., at the campsite or the off-road worksite). 
       FIG. 3  depicts a series of waveform plots  76 ,  78 ,  80 , and  82  illustrating examples of the previously discussed power conversion and control techniques of the inverter-based power supply unit  12  implemented using, for example, the control circuitry  30 . As illustrated by plot  76  of  FIG. 3 , the control circuitry  50  may generate a reference sine wave AC voltage signal  86  (e.g., modulating signal) to be compared against a generated triangular wave AC voltage signal  84  (e.g., saw-tooth carrier signal). Similarly, the control circuitry  50  may also compare an inversion of the sine wave AC voltage signal  86  against the triangular wave AC voltage signal  84 . The AC voltage signal  86  may also be totally synthesized within software stored in the memory  72  of the in the control circuitry  50 . The signals  84  and  86  may then be used to drive and/or control the power switches  60  of the inverter  43  and/or the power switches  62  of the inverter  44 . The resultant output voltage signal of the inverter  43  and/or the inverter  44  may be a pulse-width modulated (PWM) inverted signal  90  as illustrated by plot  78 . To produce the auxiliary power output  52 , the signal  90  may be then filtered (e.g., filtered via the AC output circuit  47 ) to produce a filtered (e.g., “clean” and stabilized) AC voltage signal as the auxiliary power output  52 , as illustrated by plot  80 . As previously noted, the auxiliary power output  52  may be provided at the power receptacle  20  of the inverter-based power supply unit  12  to which an external device and/or other auxiliary equipment (e.g., lighting equipment, grinding equipment, cutting tools, and so forth) may be coupled. 
     In a similar manner, to produce the welding power output  54 , a volt amp signal  91  of plot  82  may be reduced (e.g., stepped down) via the transformer  46  and converted via the DC output circuit  48  to produce a DC welding voltage signal (e.g., CC welding output) as the welding power output  54 , as illustrated by plot  82 . As also previously noted, the welding power output  54  may be provided to the welding torch  26  of the inverter-based power supply unit  12 , which may be then used to generate an electrical arc to perform one or welding operations and/or processes. It should again be appreciated that the inverter-based power supply unit  12  may produce the auxiliary power output  52  and the welding power output  54  individually or substantially simultaneously (e.g., in parallel). 
     While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.