A compressor device, a fixed-speed compressor apparatus and a method for controlling output pressure of a fixed-speed compressor

Abstract

A constant-speed air compressor unit includes a control unit for controlling the speed of a motor used to drive the compressor. The control unit includes a frequency converter to produce discrete speed regulation of the air compressor, generating additional flow and providing greater output pressure. Based on this discrete speed regulation, the air compressor operates at increased speed according to the application.

Description

Technical Field

[0001] The present disclosure relates to an air compressor having an internal frequency converter that allows for delayed maximum flow. Prior Art

[0002] A rotary screw air compressor is a positive-displacement gas compressor that uses two rotors to generate the required pressure for air compression. The rotors rotate in opposite directions, drawing air in and compressing it as the space between the rotors and the rotor housing decreases. Each screw element has a fixed built-in pressure ratio, which is determined by the screw length, pitch, and discharge port shape. To achieve maximum efficiency, this built-in pressure ratio must be adapted to the required operating pressure. The operating sequence of these compressors is determined by pressure, and different conditions within a plant result in different compressor operating loads, such as no-load, standby, and load settings. A plant's varying compressed air needs can be met using different types of compressors, such as variable speed drive (VSD) compressors or fixed-speed compressors.

[0003] Traditional fixed-speed compressors rely on the constant frequency provided by the power grid, so their motors run at a fixed speed (revolutions per minute, RPM) over time. To adjust air flow, fixed-speed air compressors adjust the intake valve to release more or less air. Once the pressure in the air storage tank reaches the set unloading pressure, the motor stops. When the compressed air is partially consumed, the pressure in the air storage tank drops. When the pressure reaches the set point, the motor starts again to drive the air compressor. If compressed air is used in large quantities, the motor will start and stop frequently, consuming more power and increasing the current during the startup process. Once the motor stops, the power is unavailable, increasing the energy consumption caused by the frequent starting and stopping of the motor. A disadvantage of traditional fixed-speed compressors is that even when air demand is low, the motor continues to run at the same fixed speed, resulting in low energy efficiency and wasted energy.

[0004] As air demand increases, a VSD compressor increases motor speed, providing more airflow. If air demand decreases, the motor automatically slows down, using only the energy needed to provide adequate airflow. VSD compressors are particularly useful on days with low production or during breaks in the workflow. Compared to traditional fixed-speed compressors, these compressors save electricity and energy costs. VSD compressors utilize the motor's infinitely variable speed to maintain constant air pressure and adjust airflow demand based on the factory's real-time needs. While VSD compressors are more energy-efficient in most applications, they are not necessary if the demand for compressed air is constant, or even nearly constant, with only occasional minor variations. For example, if the compressed air is supplied to assembly-line machinery that operates 10 to 12 hours per day, investing in a variable-speed compressor will incur additional upfront costs. Furthermore, if the VSD compressor is correctly sized based on the equipment's published maximum free air delivery (FAD), the VSD compressor may run longer than necessary, increasing maintenance costs by not shutting down.

[0005] Many compressors are often oversized based on the compressor unit's published FAD to prevent undersizing and future-proof additional airflow requirements. Consequently, oversizing results in reduced efficiency, larger compressors, and higher energy consumption. Undersizing a compressor results in pressure drops and an inability to complete the work; however, oversizing a compressor may lead to future mechanical problems or even compressor failure. Furthermore, as production demands increase and compressed air demand rises, compressors may need to be replaced and decommissioned, further increasing a plant's costs. Therefore, there is a pressing need for a compact compressor unit that can meet a plant's compressed air needs, with lower upfront costs and lower energy consumption. Summary of the Invention

[0006] Embodiments of the present disclosure relate to an air compressor comprising a housing containing a pressure vessel, a control unit, and an air compression element. The air compression element is located within the housing and configured to compress air within the pressure vessel. The air compressor includes an inverter in the electrical box and is directly coupled to a motor of the air compression element. The inverter operates the air compression element to compress air into the pressure vessel in at least three phases: loading, unloading, and stopping. During the loading phase, the inverter drives the air compression element to compress air into the pressure vessel. The pressure vessel has an outlet port through which compressed air is selectively discharged. During the unloading phase, compressed air is maintained within the pressure vessel while the air compression element operates at a reduced speed. During the stopping phase, the air compression element is stopped and the pressure within the pressure vessel is maintained. The compressor device of the present disclosure includes an inverter that provides discrete speed regulation for the motor, maintaining stable air pressure, thereby overcoming the shortcomings of existing compressors. The inverter ensures that the motor operates at a reference speed before increasing to a maximum speed or RPM.

[0007] According to an embodiment of the present disclosure, a fixed-speed air compressor is provided. The compressor includes a control unit, such as an electrical box, for controlling the speed of a motor that drives the compressor's air compression element. The motor is connected to the air compression element, such as one or more rotating elements, and generates airflow. The control unit includes an inverter for adjusting the frequency and voltage of an electrical signal transmitted to the motor, thereby controlling the motor's speed and torque output. The motor is configured to receive the electrical signal from the inverter to control its operating speed, wherein the inverter is configured to perform discrete speed adjustment of the motor's operating speed. In one embodiment, the inverter provides power to and is directly coupled to the air compression element without using any gears to connect the power supply to the air compression element. This direct coupling allows the air compressor to achieve a wide range of pressures by discretely varying the motor's operating speed. In alternative embodiments, the inverter can be coupled to the air compression element via an elastic or flexible coupling, belt, gears, or bearings. The inverter ensures that the motor operates at one or more discrete reference speeds and a discrete maximum speed. Conventional fixed-speed air compressors do not include an inverter. Therefore, conventional motors can only operate at a fixed maximum speed. The discrete speed regulation of the air compressor disclosed herein utilizes the compressor to generate additional flow, thereby outputting a higher pressure.

[0008] In one embodiment, a compressor device is provided, comprising a control unit for controlling the speed of a motor driving the compressor, wherein the control unit includes an inverter. The control unit includes a processing unit provided with an algorithm that calculates at least one reference operating speed of the motor. The algorithm may also calculate a maximum operating speed of the motor. In one embodiment, the operating speed is discretely defined as a first fixed speed and a second fixed speed. The operating speed can be increased from the reference operating speed to the maximum operating speed by a predefined percentage. Similarly, the operating speed can be decreased from the maximum operating speed to the reference operating speed by a predefined percentage.

[0009] In one embodiment, a fixed-speed compressor apparatus is provided, comprising a processing unit and a computer storage medium storing computer-executable instructions executable by the processing unit. Embodiments of the present disclosure may include or utilize computer hardware, such as a processor system (e.g., a processing unit) and system memory. The computer-readable medium storing computer-executable instructions and / or data structures is a computer storage medium (e.g., storage medium 104). Computer storage media is a physical storage medium storing computer-executable instructions and / or data structures. The computer-executable instructions executable by the processing unit include instructions for controlling the speed of a motor, thereby driving a fixed-speed compressor via an electric power inverter and performing discrete speed regulation on the motor. The computer-executable instructions may also include instructions for calculating at least one reference operating speed of the motor and a maximum operating speed of the motor.

[0010] In one embodiment, a method for controlling the outlet or output pressure of a fixed-speed compressor is provided. The method includes providing a control unit for controlling the speed of a motor driving the fixed-speed compressor, wherein the control unit includes a frequency converter and utilizing the frequency converter to discretely adjust the speed of the motor.

[0011] In one embodiment, the discrete speed regulation is defined by at least one reference speed and a maximum speed. The at least one reference speed is operable when the outlet pressure of the fixed-speed compressor is below a load setpoint. Furthermore, the maximum speed is operable when the outlet pressure of the fixed-speed compressor is between a load setpoint and an unload setpoint. Upon a step-up flow demand being placed on the fixed-speed compressor, the outlet pressure is increased from a steady-state operating level to a step-up operating level. Furthermore, the step-up operating level of the outlet pressure is above the load setpoint and below the unload setpoint. Simple diagram description

[0012] The features, aspects, and advantages of the disclosed technology can be better understood in conjunction with the following description, the appended claims, and the accompanying drawings. Those skilled in the relevant art will appreciate that the features shown in the drawings are for illustrative purposes only and are susceptible to various modifications, including different or additional features and their configurations. Figure 1 illustrates exemplary components of a compressor system according to the present disclosure; Figure 2 is a conventional art reference compressor unit pressure, speed and flow output graph; Figure 3 is an output graph of the pressure, speed and flow rate of a compressor device having a two-level discrete speed regulation in one embodiment; Figure 4 is an output graph of pressure, speed and flow rate of a compressor device with three-level discrete speed regulation in one embodiment; and FIG. 5 is an output graph showing motor speed and flow demand of a compressor device with three-level discrete speed regulation according to one embodiment. These drawings are intended to illustrate exemplary embodiments and are not drawn to scale. It should be understood that the invention is not limited to the arrangements and apparatus shown in the drawings. [definition]

[0013] To facilitate understanding of the methods and system elements disclosed in the embodiments of the present disclosure, some terms must be explained.

[0014] The terms "compressor" or "compressor device" refer to a machine that draws low-pressure gas from an auxiliary storage device as its initial input and then outputs high-pressure gas for storage or supply to other processes. The terms "compressor" and "compressor device" are not intended to be limiting and may refer to positive displacement compressors and / or dynamic compressors (turbocompressors) and / or individual components of compressors.

[0015] The term "computer storage media" refers to physical storage media that store computer-executable instructions and / or data structures. Storage media, such as digital data carriers, include computer hardware, such as random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), solid-state drives (SSD), flash memory, phase-change memory (PCM), optical disk memory, magnetic disk memory, and the like.

[0016] The term "controller" or "controller unit" generally refers to a computerized command terminal, including a collection of sensing and electrical components, used to regulate various compressor components. A compressor controller consists of at least one main processing unit with a graphical interface and instrumentation adapted to monitor various compressor components (e.g., motor, rotor, filter, bearings, valves, pressure sensors, temperature sensors).

[0017] 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, handheld devices, multiprocessor systems, microprocessor-based or programmable consumer electronics, network computers, minicomputers, mainframe computers, cellular phones, personal digital assistants (PDAs), tablet computers, pagers, routers, switches, and the like.

[0018] The term "software" generally refers to computer-executable instructions, program code, data, applications, programs, program modules, or the like in any form or type of removable media that is configured to store computer-executable instructions or other such storage in a manner accessible by a computing device.

[0019] As used herein, reference to any type of machine learning or artificial intelligence may include any type of machine learning algorithm or device, conventional convolutional neural networks, multilayer neural networks, recursive neural networks, recurrent neural networks, deep neural networks, decision tree models (e.g., decision trees, random forests, and gradient boosted trees), linear regression models, logistic regression models, support vector machines (SVMs), artificial intelligence devices, or any other type of intelligent computing system. The machine learning algorithm may be trained using any amount of training data (possibly followed by further optimization) to dynamically perform the actions of the present disclosure.

[0020] When referring to elements in the appended claims, the articles "a," "an," "the," and "said" refer to one or more of the elements. The words "including," "comprising," and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements. Implementation Method

[0021] Various embodiments of the present disclosure may be better understood by referring to the following description and accompanying drawings, wherein like reference symbols represent like elements.

[0022] While the present disclosure is susceptible to various modifications and alternative configurations, certain exemplary embodiments have been illustrated in the drawings and described below. The dimensions, angles, and curvatures shown are to be understood as exemplary and not drawn to scale.

[0023] However, it should be understood that the above is not intended to limit the disclosure to the specific embodiments disclosed, but on the contrary, it is intended to cover all modifications, alternative constructions, and equivalents within the spirit and scope of the disclosure.

[0024] According to an embodiment of the present disclosure, a fixed-speed air compressor is provided. The compressor includes a control unit, such as an electrical box, for controlling the speed of a motor that drives the compressor. The control unit includes an inverter for adjusting the frequency and voltage of an electrical signal transmitted to the motor, thereby controlling the motor's speed and torque output. The motor is configured to receive the electrical signal from the inverter to control its operating speed, wherein the inverter is configured to perform discrete speed regulation of the motor's operating speed. The inverter ensures that the motor operates at one or more discrete reference speeds and a discrete maximum speed.

[0025] FIG1 illustrates various exemplary components of a compressor system 100 (e.g., a multi-mode compressor system or apparatus) according to the present disclosure, which may include or implement one or more embodiments of the present disclosure. For example, FIG1 illustrates that compressor system 100 may include a processing unit or processor 102, storage 104, sensors 110, an input / output system 114 (I / O system 114), a communication system 116, and / or other components. Although FIG1 illustrates compressor system 100 as including specific components, it is understood that, in accordance with the present disclosure, compressor system 100 may include a varying number of additional or alternative components. Furthermore, although some of these components may be illustrated or described as distinct entities, it is understood that, in accordance with the present disclosure, these distinctions are for purposes of explanation / illustration only. For example, the functionality associated with a particular component herein may be performed by a different component or a combination of the components 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. Furthermore, the disclosed embodiments may be incorporated into oil-free compressors and various types of multi-stage compressors.

[0026] The processor 102 may include one or more electronic circuits, including any number of logic units, registers, and / or control units, to facilitate the execution of computer-readable instructions (e.g., instructions comprising a computer program). Such computer-readable instructions (e.g., instructions 106) may be stored in a memory 104. The memory 104 may include physical system memory and may be volatile, non-volatile, or some combination thereof. Furthermore, the memory 104 may include local memory, remote memory (e.g., accessible via the communication system 116 or other means), or some combination thereof. Additional details regarding the processor (e.g., processor 102) and computer storage media (e.g., memory 104) are described below.

[0027] In some embodiments, the processor 102 may include or be configured to execute any combination of software and / or hardware components that are executable to facilitate processing utilizing machine learning models or other artificial intelligence-based structures / architectures. For example, the processor 102 may include and / or utilize hardware components or computer-executable instructions that can execute such hardware components or computer-executable instructions to implement functional modules and / or processing layers, such as, but not limited to, 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 machines, restricted Boltzmann machines, and / or sparse autoencoders. machine), 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 other forms.

[0028] As will be described in further detail below, the processor 102 may be configured to execute instructions 106 stored in the memory 104 to perform certain actions associated with the operation of the compressor system 100. The execution of these actions may be based at least in part on data 108 stored in the memory 104 in a volatile or non-volatile manner.

[0029] In some examples, these actions may rely, at least in part, on the communication system 116 to receive data from other components and / or remote systems 118, which may include, for example, independent systems or computing devices, sensors, and / or others. The communication system 116 may include any combination of software or hardware components that can be executed to facilitate communication between components / devices within the system and / or components / devices outside the system. For example, the communication system 116 may include ports, buses, or other physical connections for communicating with other devices / components. Additionally or alternatively, the communication system 116 may include systems / components operable to wirelessly communicate with external systems and / or devices via any suitable communication channel, such as, but not limited to, Bluetooth, ultra-wideband, wireless local area network (WLAN), infrared communication, and / or others.

[0030] FIG1 illustrates that a compressor system 100 may include or be connected to a sensor 110 (e.g., to obtain data 108 used to perform the actions described herein). The sensor 110 may include any device for capturing or measuring data representing a perceptible or detectable phenomenon. For example, but not limited to, the sensor 110 may include one or more flow sensors, pressure sensors, humidity sensors, image sensors, microphones, thermometers, barometers, magnetometers, accelerometers, gyroscopes, and / or the like.

[0031] 1 shows that the compressor system 100 may include or be connected to an I / O system 114. The I / O system 114 may include any type of input or output device, such as, but not limited to, a display, a touch screen, a mouse, a keyboard, a controller, a speaker, and / or the like, but the present disclosure is not limited thereto.

[0032] FIG1 also illustrates other exemplary components included in or connected to the compressor system 100. For example, FIG1 illustrates the compressor system 100 as including a compressor device 101 having a compressor motor 120 configured to actuate a compressor element 122 to cause gas compression (e.g., compression of ambient air). The compressor device 101 is a fixed-speed compressor. The compressor motor 120 can take any suitable form, such as a three-phase induction motor. Similarly, the compressor element 122 can take any suitable form, such as any type of dynamic compressor (e.g., jet, centrifugal, or axial compressor) or a displacement compressor, such as a rotary compressor (e.g., a single-rotor compressor such as a vane, liquid ring, or scroll compressor; or a multi-rotor compressor such as a screw, gear, or blower compressor) or a piston compressor.

[0033] FIG1 also illustrates various other components that may operate in conjunction with the compressor motor 120 and the compressor element 122 to enhance gas compression. FIG1 illustrates the compressor system including an inlet filter 124, a warning valve 126, an air / oil reservoir separator 128, a thermostatic bypass valve 130, an oil filter 132, a safety valve 134, an oil separator 136, a minimum pressure valve 138, a solenoid valve 140, an aftercooler 142, a fan 144, an oil cooler 146, an electronic drain 148, a dryer 150 (in embodiments without the dryer 150, the electronic drain 148 may be mounted on the aftercooler 142), and an anti-condensation loop 152. As noted above, the compressor system 100 may omit one or more of the components illustrated in FIG1 or utilize alternative components / configurations, consistent with the scope of the present disclosure.

[0034] FIG1 also illustrates that the compressor system 100 includes a frequency converter 160, which is configured to be connected to a power source 162 and to the compressor motor 120 (as shown in FIG1 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 described above, the frequency converter 160 controls the operating speed of the compressor motor 120 by controlling the frequency and voltage of the compressor motor 120. The frequency converter 160 may include a rotary frequency converter, a solid-state frequency converter, or the like. The power source 162 may include a grid-connected power source or an off-grid power source.

[0035] FIG1 illustrates that the operation of the frequency converter 160 (and / or the compressor device 101) can utilize a control unit or multi-mode drive controller 164 (shown in dashed lines in FIG1 , extending from the multi-mode drive controller 164 to the frequency converter 160 and to the compressor motor 120). The compressor 101 includes an internal inverter 165 for adjusting the frequency and voltage of the electrical signal transmitted to the motor 120, thereby controlling the speed and torque output of the motor 120. The multi-mode drive controller 164 may include or operate in conjunction with the processor 102 to control the frequency converter 160 and / or the compressor motor 120. The processor 102 preferably includes an algorithm for calculating at least one reference operating speed 120 of the motor. In one embodiment, the multi-mode drive controller 164 includes an algorithm that operates in conjunction with the processor 102 to adjust the frequency and voltage of the electrical signal transmitted to the motor 120, thereby controlling the speed and torque output of the motor 120.

[0036] According to a first embodiment, the multi-mode controller is configured to operate the frequency converter 160 and / or the compressor motor 120 according to a plurality of operating modes, including at least a first compression mode 166 and a second compression mode 168 (as shown by solid lines in FIG. 1 , extending from the multi-mode drive controller 164 to the first compression mode 166 and to the second compression mode 168). The first compression mode 166 and the second compression mode 168 are associated with different motor operating speed profiles. For example, the first compression mode 166 may include a load / unload compression mode, while the second compression mode 168 may include a variable speed drive (VSD) mode. As described above, the load / unload compression modes may be associated with a plurality of states, such as a loaded state (for providing compressed air / gas), an unloaded state (e.g., an idle state), or a stopped state (e.g., such a state may be implemented after an idle period). During the loaded state (and typically the unloaded state), the compressor motor 120 operates at a substantially constant operating motor speed. This can be achieved, for example, by configuring the frequency converter 160 via the multi-mode drive controller 164 to apply a substantially constant frequency and voltage to the compressor motor 120 for operation in the loaded / unloaded compression mode, or by bypassing one or more aspects of the frequency converter 160 via the multi-mode drive controller 164 so that a constant frequency and voltage are supplied to the compressor motor 120 from the power supply 162 and / or one or more intervening components.

[0037] According to other embodiments, the multi-mode controller is configured to operate one or more other control components of the compressor system according to a plurality of operating 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.

[0038] FIG2 is a conventional output graph 200 showing the pressure in the pressure vessel, the speed of the motor, and the compressed air flow demand, wherein each output is plotted as a function of time. Graph 200 illustrates the output parameters of a conventional reference unit, which has a fixed speed drive and a maximum flow rate without delay. The motor's first reference speed 206 or reference RPM is equal to the maximum speed or RPM of the compressor unit. The reference unit in graph 200 does not include an inverter. Therefore, over time, the motor operates at a fixed maximum speed (i.e., reference speed 206) without controlling the speed based on the flow demand 201. Graph 200 begins when the reference unit is activated or turned on. The output pressure increases toward load and unload setpoints 212 and 214, reaching an initial pressure level 210 and remaining below the load setpoint 212 at a steady-state operating level 208. When the output pressure increases to the initial pressure level 210, the flow demand 201 simultaneously increases to the initial flow level 204. However, as described above, the motor of the reference unit in graph 200 will continuously operate at a reference speed 206 equal to the maximum speed, even when not always required by the factory application. Conventional fixed-speed air compressor designs do not include an inverter. Therefore, the motor of conventional designs can only operate at a fixed maximum speed. By implementing discrete speed regulation on the air compressor of the present disclosure, the compressor generates additional flow, thereby increasing the output pressure.

[0039] FIG3 is an output graph 300 showing the pressure in the pressure vessel, the speed of the motor, and the flow rate demand of the compressed air, where each output is plotted as a function of time. Graph 300 illustrates output parameters of the compressor device 101 according to one embodiment, which has a fixed speed drive and a delayed maximum flow rate. The compressor device 101 in graph 300 includes an inverter 165 configured to discretely adjust the operating speed of the motor. The discrete speed adjustment depicted in graph 300 shows a first fixed speed 306 and a second fixed speed 313. In one embodiment, the first fixed speed 306 is a reference speed, while the second fixed speed 313 is a maximum speed, wherein the first fixed speed 306 is lower than the second fixed speed 313. Graph 300 begins when the compressor device 101 is started or turned on. After startup, the motor of the compressor device 101 operates at the first fixed speed 306. When the motor operates at the first fixed speed 306, the output pressure increases to an initial pressure level 310 and the flow demand 301 increases to an initial flow level 304. The output pressure increases toward the load and unload set points 312, 314, reaching the initial pressure level 310 and remaining below the load set point 312 at a steady-state operating level 308 until the flow demand 301 increases from the first level 305 to the second level 307 and transitions to the advanced flow demand 302.

[0040] Once the compressor device 101 receives the advanced flow demand 302, the output pressure increases from the steady-state operating level 308 at a lower pressure level 315 to an advanced operating level 319 at a higher pressure level 317. As previously described, the higher pressure level 317 is higher than the load setpoint 312 and lower than the unload setpoint 314. Furthermore, once the compressor device 101 receives the advanced flow demand 302, the first constant speed 306 increases from the first discrete level 309 to the second discrete level 311, and the motor then operates at the second constant speed 313.

[0041] After the fixed-speed compressor device 101 in graph 300 has been under load for a certain period of time, between the initial pressure level 310 and the lower pressure level 315, but before reaching the load setpoint 312, the motor speed is increased by a predefined percentage from the first discrete level 309 to the second discrete level 311. This increases the compressor device 101's output flow, raising the output pressure to the advanced operating level 319. Consequently, the compressor device 101 operates at the second fixed speed 313 at maximum speed only when required by factory applications.

[0042] FIG4 is an output graph 400 of the pressure in the pressure vessel, the speed of the motor, and the flow demand of the compressed air, wherein each output is plotted as a function of time. Graph 400 illustrates output parameters of the compressor device 101 according to one embodiment, which has a fixed speed drive and a delayed maximum flow rate. The compressor device 101 in graph 400 includes an inverter 165 configured to discretely adjust the operating speed of the motor. The discrete speed adjustment graph 400 depicted in graph 400 illustrates a first fixed speed 406, a second fixed speed 413, and a third fixed speed 426. Graph 400 begins when the compressor device 101 is started or turned on. After the compressor device 101 is started, the motor of the compressor device 101 operates at a first fixed speed 406. While the motor operates at the first fixed speed 406, the output pressure increases to an initial pressure level 410 and the flow demand 401 increases to an initial flow level 404. The output pressure increases toward the load, intermediate, and unload set points 435, 436, 437, reaching the initial pressure level 410 and remaining below the load set point 435 at the steady-state operating level 408 until the flow demand 401 increases from the first level 405 to the second level 407 and transitions to the intermediate flow demand 402.

[0043] Once the compressor device 101 requires the moderate flow demand 402, the output pressure increases from the steady-state operating level 408 at the lower pressure level 415 to the moderate operating level 419 at the intermediate pressure level 417. As previously described, the intermediate pressure level 417 is higher than the load set point 435 and lower than the intermediate set point 436. Furthermore, once the compressor device 101 requires the moderate flow demand 402, the first fixed speed 406 increases from the first discrete level 409 to the second discrete level 411, and the motor then operates at the second fixed speed 413.

[0044] After the fixed-speed compressor device 101 in graph 400 has been under load for a certain period of time, between the initial pressure level 410 and the lower pressure level 415, but before reaching the load setpoint 435, the motor speed is increased by a predefined percentage from the first discrete level 409 to the second discrete level 411. This increases the compressor device 101's output flow, raising the output pressure to an intermediate operating level 419. Therefore, the compressor device 101 operates at the second fixed speed 413 under intermediate speed conditions only when required by factory applications.

[0045] When the motor is running at the second fixed speed 413, the output pressure is maintained between the load set point 435 and the intermediate set point 436. When the intermediate flow demand 402 increases from the second level 421 to the third level 422 and transitions to the advanced flow demand 403, the output pressure increases toward the intermediate and unload set points 436 and 437.

[0046] Once the compressor assembly 101 receives the advanced flow demand 403, the output pressure increases from the intermediate operating level 419 at the intermediate pressure level 430 to the advanced operating level 431 at the higher pressure level 432. As previously described, the higher pressure level 432 is higher than the intermediate set point 436 and lower than the unload set point 437. Furthermore, once the compressor assembly 101 receives the advanced flow demand 403, the second fixed speed 413 increases from the second discrete level 425 to the third discrete level 427, and the motor then operates at the third fixed speed 426.

[0047] After the fixed-speed compressor device 101 in graph 400 has been under load for a certain period of time, between intermediate pressure levels 417 and 430, but before reaching intermediate setpoint 436, the motor speed is increased by a predefined percentage from the second discrete level 425 to the third discrete level 427. This increases the compressor device 101's flow rate, raising the output pressure to the advanced operating level 431. Therefore, the compressor device 101 operates at the third fixed speed 426 under advanced speed conditions only when required by factory applications.

[0048] When the motor is running at the third fixed speed 426, the output pressure is maintained between the intermediate set point 436 and the unload set point 437. When the advanced flow demand 403 decreases from the third level 423 to the second level 424 and transitions to the medium flow demand 402, the output pressure decreases toward the load and the intermediate set points 435, 436.

[0049] Once the compressor device 101 no longer requires the advanced flow demand 403, the output pressure decreases from the advanced operating level 431 at the advanced pressure level 433 to the intermediate operating level 419 at the intermediate pressure level 434. Furthermore, once the compressor device 101 no longer requires the advanced flow demand 403, the third fixed speed 426 decreases from the third discrete level 428 to the second discrete level 429, and the motor then operates at the second fixed speed 413. Thus, the compressor device 101 operates at the third fixed speed 426 under advanced speed conditions only when required by plant applications. This saves the energy and cost of continuously operating the fixed-speed compressor at a single, fixed maximum speed during operation.

[0050] In one embodiment, the motor has three control speeds (low speed or first fixed speed level 406, reference speed or second fixed speed level 413, and maximum speed or third fixed speed level 426), which can be selected based on the output pressure and pressure setpoint. When the output pressure drops below the motor's load pressure limit or load setpoint 435, the control system can switch the motor from the unloaded state to the loaded state, where the motor operates at low speed 406 in both states. When the output pressure begins to rise, the control system can evaluate whether it is necessary to switch to the reference speed 413. This means that if the pressure increases too slowly and the output pressure remains below the intermediate load pressure limit or intermediate setpoint 436, the motor speed will increase from low speed 406 to reference speed 413. As the output pressure increases further and the speed increases, the control system should again evaluate whether it is necessary to switch to maximum speed 426. This means that if the pressure increase rate is still too slow and the output pressure remains below the maximum load pressure limit or unload set point 437, the motor speed will increase from the reference speed 413 to the maximum speed 426. If the output pressure increases and eventually exceeds the unload set point 437, the control system will switch the compressor to the unload state. This means that the compressor motor will return to the low speed 406 while the compressor circulates air within the unit.

[0051] FIG5 is a graph 500 showing the output of a compressor device 101 with three-level discrete speed regulation, plotting motor speed 502 and flow demand 510, according to one embodiment. Each output is plotted as a function of time. The motor speed 502 is defined as a first fixed speed level 504, a second fixed speed level 506, and a third fixed speed level 508. Graph 500 illustrates output parameters of the compressor device 101, according to one embodiment, having a fixed speed drive and a delayed maximum flow rate.

[0052] It should be understood that not all objects or advantages are necessarily achieved by any embodiment of the present disclosure. Those skilled in the art will appreciate that the compressor device claimed in the present disclosure can be embodied or implemented in a manner that achieves or optimizes one advantage or group of advantages as taught in the present disclosure, without necessarily achieving other objects or advantages as taught or suggested in the present disclosure.

[0053] Those skilled in the art will appreciate the interchangeability of the various features disclosed herein. In addition to the variations described herein, those skilled in the art can mix and match features with other known equivalents to construct and use a compressor device in accordance with the principles of this disclosure. For example, the inverter of a fixed-speed compressor disclosed herein can allow for discrete speed adjustment of the motor at several fixed speeds. Those skilled in the art will appreciate that the features described herein are applicable to other methods and types of air compressor devices / applications.

[0054] The present disclosure should not be limited to the embodiments described above, but may extend to other applications using the features described herein.

[0055] 100:Compressor system 101: Compressor device 102: Processing unit / processor 104: Storage 106: Instructions 108: Information 110:Sensor 114:I / O system 116: Communication System 118: Remote System 120: Motor 122: Compressor components 124: Inlet filter 126: Warning valve 128: Gas / Oil Container Separator 130: Thermostatic bypass valve 132: Oil filter 134: Safety valve 136: Oil separator 138: Minimum pressure valve 140: Solenoid valve 142: Aftercooler 144: Fan 146:Oil cooler 148: Electronic emission device 150:Dryer 152: Anti-condensation cycle 160:Frequency Converter 162: Power Supply 164: Multi-mode drive controller / control unit 165:Inverter 166: First compression mode 168: Second compression mode 200, 300, 400, 500: Curve Graph 201, 301, 401: Traffic demand 204, 304, 404: Initial flow level 206: First reference speed 208, 308, 408: Steady-state operating level 212,312,435: Load set point 214,314,437: Unload setpoint 210, 310, 410: Initial pressure levels 302,403: Advanced traffic requirements 305,405:First place 306,406: Speed 307,407,424: Second place 309,409: First discrete level 311,411,425,429: Second discrete level 313: Second fixed speed 315,415: Lower pressure level 317,432: Higher pressure level 319,431: Advanced Operation Level 402: Moderate traffic demand 413: Speed 417,430,434: Intermediate pressure level 419: Moderate operating level 423: Third rank 426: Speed 427,428: The third discrete level 433: Advanced Pressure Level 436: Intermediate set point 502: Motor speed 504: First fixed speed level 506: Second fixed speed level 508: Third fixed speed level

Claims

1. A compressor device, comprising: A control unit for controlling the speed of a motor that drives the compressor unit; the control unit includes a frequency converter. The motor is configured to receive an electrical signal from the frequency converter to control its operating speed. The frequency converter is configured to perform discrete speed regulation of the motor's operating speed according to an advanced flow requirement. The regulation includes increasing the speed from a reference operating speed to a maximum operating speed by a predetermined percentage, so that the output pressure is increased from a steady-state operating level to an advanced operating level, which is higher than the load setpoint and lower than the unload setpoint.

2. The compressor device of claim 1, wherein the inverter adjusts the frequency and voltage of the electrical signal transmitted to the motor.

3. The compressor device of claim 1, wherein the control unit includes a processing unit that provides an algorithm for calculating the reference operating speed of the motor.

4. The compressor device of claim 1, wherein the operating speed is discretely defined as a first fixed speed and a second fixed speed.

5. The compressor device as claimed in claim 4, wherein the operating speed is further discretely defined as a third fixed speed.

6. The compressor unit as claimed in claim 1, wherein the compressor unit (101) is a constant speed driven compressor.

7. A constant-speed compressor device, comprising: Processing unit; and computer storage media storing computer-executable instructions executable by the processing unit to at least: control the speed of a motor used to drive a constant-speed compressor via a power inverter; and cause discrete speed regulation of the motor according to an advanced flow requirement; wherein the discrete speed regulation includes increasing the speed of the motor from at least a reference operating speed to a maximum operating speed by a predefined percentage; so that the output pressure of the constant-speed compressor is increased from a steady-state operating level to an advanced operating level, the advanced operating level being higher than the load setpoint and lower than the unload setpoint.

8. The constant-speed compressor device of claim 7, wherein the computer storage medium further stores computer-executable instructions that can be executed by the processing unit to calculate at least one reference operating speed of the motor and the maximum operating speed of the motor (120).

9. The constant-speed compressor device as claimed in item 8, wherein the maximum operating speed is greater than the at least one reference operating speed by a predetermined percentage.

10. The constant-speed compressor device of claim 9, wherein the speed of the motor is increased from the at least one reference operating speed to the maximum operating speed by the predetermined percentage based on the increased flow demand.

11. A method for controlling the output pressure of a constant-speed compressor, the method comprising the steps of: providing a control unit for controlling the speed of a motor to drive the constant-speed compressor, wherein the control unit includes a frequency converter; using the frequency converter to perform discrete speed regulation of the motor speed; and based on an increased flow demand, increasing the speed of the motor from at least a reference operating speed to a maximum operating speed by a predefined percentage, so that the output pressure is increased from a steady-state operating level to an advanced operating level, the advanced operating level being higher than a load setpoint and lower than an unload setpoint.

12. The method of claim 11, wherein the discrete speed regulation is defined by at least one reference speed and a maximum speed.

13. The method of claim 12, wherein the at least one reference speed system is operable when the output pressure of one of the constant speed compressors is lower than the load setpoint.

14. The method of claim 12, wherein the maximum speed is operable when one of the output pressures of the constant-speed compressor is between the load setpoint and the unload setpoint.

15. The method of claim 11, wherein the motor is connected to a rotating element and generates flow.

16. The method of claim 11 further includes the step of adjusting the voltage of the frequency of the electrical signal transmitted to the motor to control the speed of the motor.

Images