Compressor control with pressure-based adaptive flow

Abstract

An air compressor (101) having an electrical inverter (165) controlling the motor (120) being coupled to an air compression element (122), with the electrical inverter (165) within a housing (119) of the air compressor (101). The inverter (165) operates at varying speeds. The inverter (165) can receive a specification of an unload air pressure characteristic and can operate at a speed that corresponds to the specification. There is an inverse relationship between inverter speed and unload air pressure setting.

Description

DescriptionCOMPRESSOR CONTROL WITH PRESSURE-BASED ADAPTIVE FLOW

[0001] FIELD OF THE DISCLOSURE

[0002] The disclosure is related to a load / unload controlled air compressor having an internal inverter that is controlling the motor and therefore also the element speed in the air compressor. The air compressor can be requested by a customer based on a desired pressure, and by adjusting parameters of the air compressor that dictate an operating speed for the air compressor, the desired pressure can be achieved. Desired pressures for various applications and customers can be achieved using the same equipment, albeit with a different fixed speed, for each application and / or customer. BACKGROUND

[0003] A rotary screw air compressor is a type of positive displacement gas compressor that uses two rotors to create pressure needed for air compression. The two rotors rotate in opposite directions to draw in air that is compressed as the space between the rotors and the rotor housing decreases. Each screw element has a fixed, built-in pressure ratio dependent on the length and pitch of the screw, and form of the discharge port. To attain maximum efficiency, the built-in pressure ratio must be adapted to the required working pressure. The order of operation of these compressors is determined by the pressure values, and the different scenarios that arise in the factory present varying compressor loads of operation, such as no-load, standby, and load settings. The varying compressed air requirements of a factory can be met by different types of compressors, such as a variable speed drive (VSD) or fixed speed compressor.

[0004] Traditional fixed speed compressors operate at fixed revolutions per minute (RPM) over time since a constant frequency, depending on the grid, is supplied to the motor. To adjust the airflow amount, a fixed-speed air compressor requires alternating between a full-load state and a no-load state. Once the pressure of the gas storage tank reaches the unload pressure setting, the compressor goes through unload and eventually stops. And when the compressed air is partially used, the pressure of the air storage tank decreases. After the pressure reaches a load level pressure, the motor is started again to drive the air compressor to work. The air compressor can also switch during unload towards a load. If the compressed air is used a lot, the motor will start and stop frequently, and the motor will consume more electric energy while the electric current is larger during the starting process. A disadvantage of traditional fixed speed compressors is that, even when the air demand is low, the motor always operates at the same fixed speed. Thus, this leads to a less energy-efficient process and is a waste of energy.

[0005] VSD compressors increase the speed of the motor as the need for air increases, thus supplying more flow. If the demand for air decreases, the motor will automatically slow down and only use the required energy to provide appropriate flow. During slow production days or breaks in workflow, VSD compressors are especially useful. This type of air compressor saves electricity and energy cost, compared to traditional fixed speed models. VSD compressors use stepless speed regulation characteristics of the motor for air pressure stability and thus address airflow needs according to the realtime demand for a factory. While VSD compressors are more energy-efficient for most applications, they are not necessary if the compressed air needs are constant, or even mostly constant with only occasional slight variations. For example, if the compressed air application is to run assembly-line machinery for 10-12 hours per day, investing in a variable speed compressor will require extra up-front costs.

[0006] Many compressors are often oversized based on the published FAD of the compressor device to prevent under sizing and the need of an extra “future-proof’ flow. As a result, the oversizing results in less efficient, bigger compressors and high energy consumption. Under sizing a compressor will result in pressure drops and inability to complete a task; however, oversizing the compressor can lead to future mechanical problems and potential failure of the compressor. Moreover, it may become necessary to switch and uninstall compressors as production needs increase and demand for compressed air rises. This subsequently increases costs imposed on the factory. As such, there is a need for a compact compressor device that satisfies the compressed air requirements of a factory with reduced up-front costs and low energy consumption.SUMMARY

[0007] Embodiments of the present disclosure are directed to a method for providing an air compressor to a customer that efficiently meets the stated needs of the customer. The method includes receiving a specified unload pressure from a customer. The air compressor has an internal inverter controlling a motor that is coupled to an element of the air compressor. The method also includes adjusting a speed of the motor and element based, at least in part, upon a relationship between the motor speed and the requested outlet pressure.

[0008] Further embodiments of the present disclosure are directed to an air compressor including an inverter. The inverter is located within the air compressor. A customer provides a specified output air pressure target. The element pressurizes air towards the target. The air compressor also includes a processor and a memory storing computer- readable instructions that including receiving a specified output air pressure target, calculating a speed for the inverter based, at least in part, upon the specified maximumoutput air pressure target, recording the speed, and operating the air compressor at the speed.

[0009] Still further embodiments of the present disclosure are directed to an air compressor including a housing defining a pressure vessel and an electrical cubicle, the electrical cubicle being sealed from the pressure vessel, and an air compression element operably coupled to the pressure vessel and being configured to force compressed air into the pressure vessel. The air compressor also includes an internal inverter in the electrical cubicle and a motor being coupled to the air compression element and configured to operate the air compression element at a range of speeds. The air compressor also receives a desired output pressure band from a customer for the air compressor, calculates a corresponding setting for the inverter to achieve the maximum outlet pressure of the pressure band. There is an inverse relationship between speed and output pressure. The air compressor also sets the internal inverter to operate at the corresponding speed and operates the air compressor at the corresponding speed.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Features, aspects, and advantages of the presently disclosed technology may be better understood concerning the following description, appended claims, and accompanying drawings. A person skilled in the relevant art will understand that the features shown in the drawings are purposes of illustration, and variations, including different or additional features and arrangements thereof, are possible.

[0011] Figure 1 illustrates that a compressor system may comprise or be in communication with sensor(s) according to embodiments of the present disclosure.

[0012] Figure 2 is a graph of torque against speed for a motor of an air compressor according to embodiments of the present disclosure.

[0013] Figure 3 is a graph of torque against a motor of an air compressor having multiple speeds according to embodiments of the present disclosure.

[0014] The drawings are to illustrate exemplary implementations and are not drawn to scale. It is understood that the inventions are not limited to the arrangements and instrumentalities shown in the drawings.

[0015] DEFINITIONS

[0016] For ease of understanding the disclosed embodiments of the disclosed method and system elements, a description of a few terms is necessary.

[0017] The term ‘compressor’ or ‘compressor device’ refers to a machine that draws low- pressure gas from auxiliary storage as raw input and then outputs high-pressure gas, either for storage or to feed other processes. The terms ‘compressor’ and ‘compressor device’ are not intended to be limiting in scope and may refer to positive displacementcompressors and / or dynamic compressors (turbocompressors) and / or individual components of compressors.

[0018] The term ‘computer storage media’ refers to physical storage media that store computer-executable instructions and / or data structures. Storage media, such as a digital data carrier, includes computer hardware, such as random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), solid state drives (SSDs), flash memory, phase-change memory (PCM), optical disk storage, magnetic disk storage, and the like.

[0019] The term ‘controller’ or ‘controller unit’ generally refers to a computerized command terminal comprising a collection of sensors and electrical components i.e., to regulate various compressor elements. Compressor controllers include at least one main processing unit with a graphical interface and are adapted to monitor the instrumentation of various compressor parts (e.g., motors, rotors, filters, bearings, valves, pressure sensors, temperature sensors).

[0020] The term ‘processor’ or ‘processing unit’ refers to one or more devices, circuits, and / or processing cores configured to process data, such as computer program instructions, and includes personal computers, desktop computers, laptop computers, message processors, hand-held devices, multi-processor systems, microprocessor-based or programmable consumer electronics, network PCs, minicomputers, mainframe computers, mobile telephones, PDAs, tablets, pagers, routers, switches, and the like.

[0021] The term ‘software’ generally refers to computer-executable instructions, code, data, applications, programs, program modules, or the like maintained in or on any form or type of computer-readable media that is configured for storing computer-executable instructions or the like in a manner that is accessible to a computing device.

[0022] As used herein, reference to any type of machine learning or artificial intelligence may include any type of machine learning algorithm or device, convolutional neural network(s), multilayer neural network(s), recursive neural network(s), recurrent neural network(s), deep neural network(s), decision tree model(s) (e.g., decision trees, random forests, and gradient boosted trees) linear regression model(s), logistic regression model(s), support vector machine(s) (SVM), artificial intelligence device(s), or any other type of intelligent computing system. Any amount of training data may be used (and perhaps later refined) to train the machine learning algorithm to dynamically perform the disclosed operations.

[0023] When introducing elements in the appended claims, the articles “a,” “an,” “the,” and “said” are intended to mean there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.DETAILED DESCRIPTION

[0024] A better understanding of different embodiments of the disclosure may be had from the following description read with the drawings in which like reference characters refer to like elements.

[0025] While the disclosure is susceptible to various modifications and alternative constructions, certain illustrative embodiments are in the drawings and are described below. The dimensions, angles, and curvatures represented are to be understood as exemplary and are not necessarily shown in proportion.

[0026] It should be understood, however, there is no intention to limit the disclosure to the specific embodiments disclosed, but on the contrary, the intention covers all modifications, alternative constructions, and equivalents falling within the spirit and scope of the disclosure.

[0027] According to embodiments of the present disclosure, and with reference to Figure 1, an air compressor 101 is provided that has an electrical inverter 165 that is located within an electrical cubicle 123, the electrical cubicle 123 arranged within a housing 119 of the compressor 101. The role of the inverter can be replicated by a soft starter, or a DOL- or Y-D starter. The air compressor 101 is a fixed-speed configuration in which a speed is chosen, and the air compressor 101 runs at that speed. There is an inverse relationship between desired output air pressure and the speed at which the air compressor 101 runs. The higher the desired pressure, the lower the speed, and vice versa. The speed of the air compressor 101 can be altered at any time through software or firmware. Accordingly, a single piece of equipment can be altered without changing any underlying hardware. Within a certain range, a single commercially- offered compressor can be easily adjusted to meet the needs of specific customers. This adjustability also meets customers’ needs more precisely. Instead of having several available compressors with different pressure offerings at discrete levels, such as 7 bar, 9 bar, 13 bar, etc. levels, the present air compressors can meet the desired pressure output specifications precisely. Another advantage is that at any speed (and associated pressure output specification) the present air compressors operate at a desirable power level efficiently.

[0028] The air compressor 101 also includes a pressure vessel 121 and an element 122. The electrical cubicle 123 of the air compressor can be located conveniently relative to the pressure vessel 121 and element 122 and arranged within a housing 119. The inverter 165 provides power and is directly coupled to the element 122 of the air compressor 101 and does not involve any gears connecting a power source to element 122. The direct coupling allows for the air compressor 101 to achieve a wide range of pressures by varying the speed at which the element 122 runs. In alternative embodiments,the inverter 165 may be coupled to the air compression element 122 by means of elastic or flexible couplings, belts, gears, or bearings to connect the inverter 165 to the air compression element 122. With this system, and within a certain range, a single design of an air compressor 101 can be maintained that can be adjusted in terms of operating speed to achieve a specified pressure within the range. This obviates the need to maintain different sizes, or configurations of air compressors within the range. Instead, a single, identical air compressor can be sold and suitably configured based on a requested pressure delivery parameter, and by adjusting the speed of the inverter and direct coupling to the element in the air compressor, the requested pressure can be achieved.

[0029] Figure 1 illustrates various example components of an example compressor system 100 (e.g., a multi-modal compressor system) that may comprise or implement one or more disclosed embodiments. For example, Figure 1 illustrates that a compressor system 100 may include processor(s) 102, storage 104, sensor(s) 110, input / output system(s) 114 (VO system(s) 114), communication system(s) 116, and / or other components. Although Figure 1 illustrates a compressor system 100 as including particular components, one will appreciate, in view of the present disclosure, that a compressor system 100 may comprise any number of additional or alternative components. Furthermore, although some of the components may be illustrated or described as distinct entities, one will appreciate, in view of the present disclosure, that such distinctions are made for the sake of explanation / description only. For example, functionality described herein in association with a particular component may be performed by a different component or a combination of components as described herein. Accordingly, aspects of the components described herein may be combined with other components or divided into multiple components in accordance with the present disclosure. Additionally, aspects of the present disclosure may be incorporated into oil-free compressors and various types of multi-stage compressors.

[0030] The processor(s) 102 may comprise one or more sets of electronic circuitries that include any number of logic units, registers, and / or control units to facilitate the execution of computer-readable instructions (e.g., instructions that form a computer program). Such computer-readable instructions may be stored within storage 104 (e.g., instructions 106). The storage 104 may comprise physical system memory and may be volatile, non-volatile, or some combination thereof. Furthermore, storage 104 may comprise local storage, remote storage (e.g., accessible via communication system(s) 116 or otherwise), or some combination thereof. Additional details related to processors (e.g., processor(s) 102) and computer storage media (e.g., storage 104) will be provided hereinafter.

[0031] In some implementations, the processor(s) 102 may comprise or be configurable to execute any combination of software and / or hardware components that are operable to facilitate processing using machine learning models or other artificial intelligencebased structures / architectures. For example, processor(s) 102 may comprise and / or utilize hardware components or computer-executable instructions operable to carry out function blocks and / or processing layers configured in the form of, by way of non-limiting example, single-layer neural networks, feed forward neural networks, radial basis function networks, deep feed-forward networks, recurrent neural networks, long-short term memory (LSTM) networks, gated recurrent units, autoencoder neural networks, variational autoencoders, denoising autoencoders, sparse autoencoders, Markov chains, Hopfield neural networks, Boltzmann machine networks, restricted Boltzmann machine networks, deep belief networks, deep convolutional networks (or convolutional neural networks), deconvolutional neural networks, deep convolutional inverse graphics networks, generative adversarial networks, liquid state machines, extreme learning machines, echo state networks, deep residual networks, Kohonen networks, support vector machines, neural Turing machines, and / or others.

[0032] As will be described in more detail, the processor(s) 102 may be configured to execute instructions 106 stored within storage 104 to perform certain actions associated with operation of the compressor system 100. The actions may rely at least in part on data 108 stored on storage 104 in a volatile or non-volatile manner.

[0033] In some instances, the actions may rely at least in part on communication system(s) 116 for receiving data from other components and / or remote system(s) 118, which may include, for example, separate systems or computing devices, sensors, and / or others. The communications system(s) 116 may comprise any combination of software or hardware components that are operable to facilitate communication between on-system components / devices and / or with off-system components / devices. For example, the communications system(s) 116 may comprise ports, buses, or other physical connection apparatuses for communicating with other devices / component s. Additionally, or alternatively, the communications system(s) 116 may comprise systems / components operable to communicate wirelessly with external systems and / or devices through any suitable communication channel(s), such as, by way of nonlimiting example, Bluetooth, ultra-wideband, WLAN, infrared communication, and / or others.

[0034] Figure 1 illustrates that a compressor system 100 may comprise or be in communication with sensor(s) 110 (e.g., to obtain data 108 used to perform acts described herein). Sensor(s) 110 may comprise any device for capturing or measuring data representative of perceivable or detectable phenomena. By way of non-limiting example, the sensor(s) 110 may comprise one or more flow sensors, pressure sensors,hygrometers, image sensors, microphones, thermometers, barometers, magnetometers, accelerometers, gyroscopes, and / or others.

[0035] Furthermore, Figure 1 illustrates that a compressor system 100 may comprise or be in communication with VO system(s) 114. I / O system(s) 114 may include any type of input or output device such as, by way of non-limiting example, a display, a touch screen, a mouse, a keyboard, a controller, a speaker, and / or others, without limitation.

[0036] Figure 1 also illustrates additional example components of or in communication with the compressor system 100. For instance, Figure 1 illustrates the compressor system 100 comprising a compressor device 101 with a compressor motor 120 configured to actuate a compressor element 122 to facilitate gas compression (e.g., compression of ambient air). The compressor motor 120 may take on any suitable form, such as a three-phase induction motor. Similarly, the compressor element 122 may take on any suitable form, such as any type of dynamic compressor (e.g., ejector, radial, or axial compressor) or displacement compressor such as a rotary compressor (e.g., a single rotor such as a vane, liquid ring, or scroll compressor; or a multi-rotor compressor such as a screw, tooth, or blower compressor) or a piston compressor.

[0037] Figure 1 also illustrates various additional components that may operate in conjunction with the compressor motor 120 and the compressor element 122 to facilitate gas compression. Figure 1 illustrates the compressor system as including an inlet filter 124, a sentinel valve 126, air / oil vessel separator 128, thermostatic bypass valve 130, oil filter 132, safety valve 134, oil separator 136, minimum pressure valve 138, solenoid valve 140, after cooler 142, fan 144, oil cooler 146, electronic drain 148, a dryer 150 (the electronic drain 148 can be mounted on the after cooler 142 in implementations that omit the dryer 150), and a condensate prevention cycle 152. As noted above, one or more of the components shown in Figure 1 may be omitted from a compressor system 100, or alternative components / structures may be utilized in accordance with the scope of the present disclosure.

[0038] Figure 1 also illustrates the compressor system 100 as including a frequency converter 160 configured to connect to a power source 162 and to the compressor motor 120 (as indicated in Figure 1 by dashed lines extending from the power source 162 to the frequency converter 160 and from the frequency converter 160 to the compressor motor 120). As discussed above, the frequency converter 160 controls the operational motor speed of the compressor motor by controlling the frequency and voltage of the compressor motor 120. The frequency converter 160 may comprise a rotary frequency converter, a solid state frequency converter, etc. The power source 162 may comprise a grid-connected power source or an off-grid power source.

[0039] Figure 1 depicts that operation of the frequency converter 160 (and / or the compressor motor 120) may be controlled by a multi-modal drive controller 164 (as indicated inFigure 1 by dashed lines extending from the multi-modal drive controller 164 to the frequency converter 160 and to the compressor motor 120). The multi-modal drive controller 164 may comprise or operate in conjunction with the processor(s) 102 to govern operation of the frequency converter 160 and / or the compressor motor 120.

[0040] According to a first embodiment, the multi-modal controller 164 is configured to operate the frequency converter 160 and / or the compressor motor 120 according to a plurality of operational modes including at least a first compression mode 166 and a second compression mode 168 (as indicated in Figure 1 by solid lines extending from the multi-modal drive controller 164 to the first compression mode 166 and the second compression mode 168). The first compression mode 166 and the second compression mode 168 are associated with different operational motor speed profiles. For example, the first compression mode 166 may comprise a load / unload compression mode, and the second compression mode 168 may comprise a VSD mode. As noted above, the load / unload compression mode may be associated with multiple states, such as a load state (to provide compressed air / gas), an unload state (e.g., idling), or a stop state (e.g., which may be implemented after a period of idling). During the load state (and often the unload state), the compressor motor 120 runs at a substantially constant operational motor speed. This can be accomplished, for example, by configuring the frequency converter 160, via the multi-modal drive controller 164, to impose a substantially constant frequency and voltage for the compressor motor 120 for operation in the load state of the load / unload compression mode, or by bypassing, via the multi-modal drive controller 164, one or more aspects of the frequency converter 160 to allow a constant frequency and voltage to be supplied to the compressor motor 120 from the power source 162 and / or one or more intervening components.

[0041] As also noted above, a VSD mode is associated with variable operational motor speed of the compressor motor 120, which can be accomplished by causing, via the multi-modal drive controller 164, the frequency converter 160 to dynamically modify the frequency and voltage for operation of the compressor motor 120. The motor speed for the compressor motor 120 (and / or the associated voltage / frequency) may be dynamically determined based upon a demand associated with usage of the compressor system, such as a requested flow of compressed air, a current compressed air pressure of the compressor system 100, etc.

[0042] According to other embodiments, the multi-modal controller 164 is configured to operate the one or more other control components of the compressor system 100 according to a plurality of operational modes including at least a first compression mode and a second compression mode. Such control components may include one or more solenoids, one or more control timers, and / or one or more pressure vessel controls.

[0043] Figure 2 is a graph 200 of torque against speed for a motor of an air compressor according to embodiments of the present disclosure. The air compressor includes a power source, such as a motor which can be an electric motor or a combustion engine or another suitable power source. Plot 202 shows a constant torque motor curve that is characteristic of this type of air compressor. With this design, each air compressor must be individually built to achieve the desired pressure output, which is costly in terms of the manufacturing and logistics of maintaining multiple different inventory items.

[0044] The air compressors of the present disclosure can achieve a desired pressure output using the same equipment adjusted in terms of the speed of the element. There is a pressure vessel and a power inverter inside the pressure vessel that is directly coupled to an element to drive the element. There are no gears between the power source and the element. This configuration allows for customizability of the output of the air compressor that is not available through other air compressors. A customer specifies a desired pressure output and the speed of the air compressor can be adjusted to a corresponding value, which speed is set in the air compressor, and the air compressor is now suited to the customer’s specifications without incurring the expense and administrative overhead of maintaining different air compressors having different outputs and selecting the correct pressure level, etc. Instead, the speed of the element is fixed at a suitable speed and the air compressor will meet the customer’s needs.

[0045] Plot 204 represents a selected unload pressure that is selected by the customer, and line 206 represents a speed that corresponds to that desired unload pressure. The torque and outlet pressure are analogous. There is an inverse relationship between the speed of the element and the desired output pressure. That is, a higher output pressure is achieved by a lower speed, and a lower output pressure is achieved by a higher speed.

[0046] As observed in Figure 3, some embodiments of the air compressor have different fixed speeds. Figure 3 is a graph 300 of torque against speed for a motor of an air compressor according to embodiments of the present disclosure having three fixed speeds. For the sake of this discussion an air compressor with three speeds, or three fixed speed levels, is discussed: low speed 302, reference speed 304, and maximum or high speed 306. The motor speed is selected based on the outlet pressure 308 desired as specified from a customer. When the outlet pressure 308 drops below the load pressure limit of the compressor, the control system should switch the compressor from the unloaded state to the load state, in both cases the motor is running at a low speed 302. As the outlet pressure 308 begins to rise, the control system evaluates if there is a need to switch to the reference speed 304. This means that when the pressure rise is too slow and the outlet pressure 308 will remain below the load pressure limit, the motor speed will increase from low speed 302 to reference speed 304. As the outlet pressure 308begins to rise further and faster, the control system should evaluate again if there is the extra need to switch to the max speed 306. This means that when the pressure rise is still too slow and the outlet pressure 308 will remain below the load level, the motor speed will increase from reference speed 304 to max speed 306. If the outlet pressure 308 increases and eventually exceeds the unload pressure limit, the control system should switch the compressor to the unloaded state. This means that the compressor motor will go to again low speed 302 while the compressor recirculates the air inside the compressor. It is contemplated that the air compressor may have two or more speeds, meaning that the disclosure is not limited to three speeds.

[0047] It is to be understood that not necessarily all objects or advantages may be achieved under any embodiment of the disclosure. Those skilled in the art will recognize that the claimed compressor device may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without achieving other objects or advantages as taught or suggested herein.

[0048] The skilled artisan will recognize the interchangeability of various disclosed features. Besides the variations described herein, other known equivalents for each feature can be mixed and matched by one of ordinary skill in this art to build and use a compressor device under principles of the present disclosure. For example, an inverter of the disclosed fixed-speed compressor may permit discrete speed regulation of a motor with several fixed speeds. It will be understood by the skilled artisan that the features described herein may be adapted to other methods and types of air compressor devices / applications.

[0049] It is intended that the present disclosure should not be limited by the disclosed embodiments described above and may be extended to other applications that may employ the features described herein.

Claims

Claims

1. A method, comprising: receiving a specified unload pressure from a customer; in an air compressor (101 having an internal inverter (165) controlling a motor (120) that is coupled to an element (122) of the air compressor (101), adjusting a speed of the motor (120) and element (122) based, at least in part, upon a relationship between the motor speed and the specified unload pressure; and providing the air compressor (101) to the customer with the speed set in the air compressor (101) at a level that meets requirements of the specification.

2. The method of claim 1, further comprising checking the specification against a known range in which the inverter (165) runs efficiently.

3. The method of claim 1 wherein the inverter (165) runs at a maximum power at the speed and unload pressure.

4. The method of claim 1, further comprising receiving updated specifications from the customer and adjusting the speed of the internal inverter (165) accordingly.

5. The method of claim 1 wherein the speed of the motor (120) is controlled at three fixed levels, said three fixed levels being a low speed, a high speed, and a reference speed defined between the low speed and high speed.

6. The method of claim 5 wherein, in response to receiving updated specifications from the customer, the reference speed is increased to the high speed based on the specified unload pressure and a maximum power of the inverter (165).

7. An air compressor (101), comprising: an inverter (165) controlling a motor (120) that is coupled to an element (122) in the air compressor, the inverter (165) being located within the air compressor (101), the element (122) being configured to pressurize air; a processor (102); a memory (104) storing computer-readable instructions (106) that, when executed, cause the processor (102) to: receive a specified output air pressure targets;calculate a speed for the inverter (165) based, at least in part, upon a specified maximum output air pressure target; recording the speed; and operating the air compressor (101) at a fixed, recorded speed.

8. The air compressor (101) of claim 7, wherein the processor(102) is further configured to measure the output air pressure and comparing the output air pressure to the target.

9. An air compressor (101), comprising: a housing (119) defining a pressure vessel (121) and an electrical cubicle (123), the electrical cubicle (123) being sealed from the pressure vessel (121); at least one air compression element (122) operably coupled to the pressure vessel (121) and being configured to force compressed air into the pressure vessel (121); an internal inverter (165) in the electrical cubicle (123) controlling the motor (120) being coupled to the at least one air compression element (122) and configured to operate the at least one air compression element (122) at a range of speeds; a processor (102); and a memory (104) configured to store instructions (106) that, when executed by the processor (102), causes the processor (102) to perform a plurality of actions, the actions comprising: receiving a desired outlet pressure band from a customer for the air compressor; calculating a corresponding setting for the inverter (165) to achieve the desired outlet pressure band, wherein there is an inverse relationship between speed and output pressure; setting the internal inverter (165) to operate at the corresponding speed; and operating the air compressor (101) at the corresponding speed.

10. The air compressor (101) of claim 9, the actions further comprising receiving an updated desired speed, calculating an updated corresponding speed, and setting the inverter (165) to operate at the updated corresponding speed.

11. The air compressor (101) of claim 9 wherein the internal inverter(165) operates at a maximum power at substantially an entire range of speeds for a corresponding unload pressure.

12. The air compressor (101) of claim 9 wherein the range of speeds include a fixed low speed, a fixed reference speed, and a fixed maximum speed.

13. The air compressor of claim 12 wherein the fixed low speed is increased to the fixed reference speed based on the processor (102) receiving the desired outlet pressure band from the customer for the air compressor (101).

14. The air compressor of claim 12 wherein the fixed reference speed is increased to the fixed maximum speed in response to the processor (102) receiving the desired outlet pressure band from the customer for the air compressor (101).

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