Gas suspension oil-free vpsa oxygen production system and method based on multi-dimensional closed-loop control

Abstract

The application relates to the technical field of oxygen production, and discloses a gas suspension oil-free VPSA oxygen production system and method based on multi-dimensional closed-loop control. The system adopts a direct connection architecture without a buffer tank, calculates real-time surge margin through a sensing reconstruction module, drives a power bypass module to dynamically match fluid impedance to suppress surge. A thermal control buffer module is introduced, and dynamic thermal interlocking logic is used to lock cooling adjustment under sensitive working conditions, and temperature fluctuations are smoothed through thermal capacity buffering. A central decision module executes density compensation and time sequence feedforward strategy, and adjusts compressor torque and valve opening slope according to inlet density and process time sequence. The application uses closed-loop control logic based on real-time surge margin and its change rate to drive a high-speed unloading valve to provide a discharge channel when the system impedance abnormally rises, effectively suppressing the fluid dynamics instability of the direct connection system caused by process switching and the equipment overload risk caused by environmental load changes.

Description

Technical Field

[0001] This invention relates to the field of oxygen production technology, specifically to an oil-free VPSA oxygen production system and method based on multi-dimensional closed-loop control. Background Technology

[0002] Pressure swing adsorption (PSA / VPSA) gas separation technology is the mainstream method for industrial gas production (such as oxygen and nitrogen production). This technology utilizes the selective adsorption characteristics of zeolite molecular sieves for nitrogen, separating oxygen from the air through a periodic process of pressure adsorption and decompression desorption. With the increasing demands for gas quality in high-end manufacturing and medical applications, oil-free centrifugal compressors using suspended bearing technology are gaining popularity due to their advantages such as being completely oil-free, highly energy-efficient, maintenance-free, and low-noise.

[0003] In existing industrial applications, to isolate the pressure pulsations generated during adsorption tower switching, a large-volume air buffer tank is typically installed between the Roots blower or centrifugal compressor and the adsorption tower. This buffer tank acts as a damping element, providing the power source with a relatively stable back pressure environment and reducing the complexity of the control system. Traditional control strategies often employ independent single-loop feedback control. Pressure transmitters collect signals, and PID controllers adjust the inlet guide vanes or motor frequency accordingly to maintain pressure stability; the cooling system simply turns on the water pump or fan based on the fluid temperature setpoint.

[0004] However, existing VPSA oxygen generation technologies suffer from significant footprint issues due to their buffer tanks, increasing infrastructure investment. Furthermore, the large volumetric inertia, while mitigating pressure, also slows the system's response to flow rate demands. The existing thermal management logic's simplistic temperature control action can lead to thermal deformation or fluid vibration at precision joints. Additionally, decreases in ambient temperature or fluctuations in intake pressure increase air density, causing a sharp rise in the compressor's mass flow rate and compression power consumption at the same speed, affecting the continuous stability of the gas supply system. A single temperature control logic is prone to thermal deformation in precisely fitted suspension systems, and while the large buffer volume mitigates pressure, it also slows the system's response to flow rate changes. Therefore, this invention provides an oil-free VPSA oxygen generation system and method based on multi-dimensional closed-loop control to address the shortcomings of existing technologies. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an air-suspension oil-free VPSA oxygen generation system and method based on multi-dimensional closed-loop control, which solves the problems of volume redundancy and dynamic response lag caused by the reliance on large-volume buffer tanks in existing VPSA oxygen generation systems.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] The first aspect of this invention provides an oil-free VPSA oxygen generation system based on multi-dimensional closed-loop control, comprising:

[0008] The perception and reconstruction module is used to collect physical field signals and reconstruct virtual state parameters that reflect the thermodynamic and dynamic state of the system using algorithms.

[0009] The central decision-making module is used to calculate and generate multi-dimensional coupled control commands using the virtual state parameters as input;

[0010] The power bypass module is used to adjust the operating conditions of the air-suspended oil-free air compressor in response to the multi-dimensional coupling control command, and to build a fluid work benchmark under the direct connection architecture.

[0011] The thermal control buffer module is used to execute dynamic and thermal interlock logic based on the multidimensional coupling control command, and to construct a stable thermodynamic boundary by utilizing the thermal capacity inertia of the coolant buffer tank.

[0012] The fluid valve array module is used to perform opening slope reconstruction according to the multi-dimensional coupling control command and to perform impedance dynamic matching on the airflow output by the fluid work reference.

[0013] The adsorption process module receives the matched airflow through an airflow distributor and performs gas separation using an adaptive spring clamping device.

[0014] Preferably, the power bypass module includes an air-suspended oil-free air compressor and an electronic bypass circuit.

[0015] The air-suspension oil-free air compressor adopts an integrated direct-drive structure. The internally integrated high-speed permanent magnet motor supports the rotor shaft system through a suspension bearing assembly, and the exhaust port is directly connected to the inlet of the downstream fluid valve array module through a rigid pipe.

[0016] The electronic bypass circuit is connected in parallel to the exhaust pipe of the air-suspended oil-free air compressor. The actuator is a high-speed proportional unloading valve, which is a controlled variable impedance element used to provide a low-impedance fluid discharge channel when an abnormal increase in system impedance is detected.

[0017] The opening control of the high-speed proportional unloading valve follows the impedance dynamic matching logic. The opening command is adjusted based on the real-time surge margin and the rate of change. When the system determines that it is on the edge of surge, the opening of the high-speed proportional unloading valve is calculated by the difference between the proportional gain coefficient acting on the safe surge margin threshold and the real-time surge margin, and by combining the differential gain coefficient acting on the time derivative of the surge margin. This is used to move the operating point of the air-suspended oil-free air compressor to a region far away from the surge boundary line.

[0018] Preferably, the thermal control buffer module includes a variable frequency water pump, a three-way proportional flow divider valve, and a coolant buffer tank connected in series in the circulation pipeline.

[0019] The coolant buffer tank is an insulated fluid container with a preset volume, specifically a thermal inertial generator, and its volume is designed to match the maximum allowable temperature rise rate and the amplitude of heat load fluctuation.

[0020] The central decision module is used to execute the dynamic and thermal interlock logic, which divides the oxygen production system's operating state into a stable adjustment range and a sensitive locking range. When the real-time surge margin is lower than the preset adjustment lockout threshold or the process sequence is about to enter the pressure equalization step, it is determined that the sensitive locking range has been entered.

[0021] Within the sensitive locking range, the central decision module generates a state freeze command, forcing the variable frequency water pump to maintain its current speed and locking the current opening of the three-way proportional flow divider valve. At this time, the coolant buffer tank absorbs or releases heat by utilizing the sensible heat capacity of the storage medium, limiting the rate of change of fluid temperature over time and maintaining a relatively stable thermodynamic boundary.

[0022] Preferably, the adsorption process module includes adsorption tower A and adsorption tower B operating in parallel:

[0023] Each adsorption tower has an integrated airflow distributor at its bottom inlet. The airflow distributor has an inverted conical diversion chamber inside. The sidewall of the conical diversion chamber has guide holes with gradually increasing diameters from bottom to top, which are used to convert the high-speed axial jet into a low-speed radial laminar flow and distribute it evenly to the molecular sieve bed.

[0024] Each adsorption tower is equipped with an adaptive spring clamping device at the top. The adaptive spring clamping device is configured as a passive mechanical feedback mechanism. It applies axial pre-tightening force to the air-permeable clamping plate through a high-stiffness helical spring and uses the extension and retraction displacement of the spring to absorb the slight deformation of the bed caused by the pressure fluctuation of the direct connection system, so as to ensure that the real-time clamping force applied to the top of the molecular sieve bed is maintained within the effective clamping range.

[0025] The adsorption process module performs gas separation using pressure swing adsorption or vacuum pressure swing adsorption.

[0026] Preferably, the fluid valve array module includes a tower top equalizing valve, a tower bottom equalizing valve, and a single-tower gas supply valve:

[0027] The fluid valve array module is used to perform opening slope reconstruction. The instantaneous opening command when the valve moves follows a preset trajectory generation function. The trajectory generation function is composed of a basic opening slope function and a correction term based on mechanical vibration feedback. The basic opening slope function is determined based on the process cycle time and shape factor, so that the valve acts as a variable throttling element with variable damping during the opening process.

[0028] Preferably, the perception reconstruction module includes an inlet sensor group arranged at the air intake, and the computing unit within the perception reconstruction module is used to execute a virtual sensing algorithm to reconstruct real-time intake density parameters.

[0029] The computing unit calculates the real-time intake density parameters based on the absolute pressure and thermodynamic temperature collected by the inlet sensor group and using the gas state equation, which includes corrections for gas compressibility factor and humid air-to-gas ratio constant.

[0030] Preferably, the sensing reconstruction module includes a group of process sensors distributed in the adsorption tower and pipelines, and the computing unit is also used to reconstruct the real-time surge margin based on a preset compressor performance spectrum.

[0031] The computing unit maps the real-time operating pressure ratio, calculated from the ratio of exhaust pressure to intake pressure collected by the process sensor group, and the reduced speed, which is obtained by correcting the real-time physical speed based on the intake temperature, onto the compressor performance map that defines the surge boundary line, and calculates and generates a real-time surge margin that represents the degree to which the current operating point approaches the hydrodynamic instability boundary.

[0032] Preferably, the central decision module is used to execute a load stabilization control algorithm. Based on the received real-time intake density and intake pressure parameters, it dynamically monitors the real-time load status of the air-suspended oil-free air compressor. When the real-time intake density or intake pressure increases, causing the equivalent load torque to approach the rated current limit of the motor, the central decision module generates a speed derating command or a torque clamping command to actively reduce the target speed or output torque of the air-suspended oil-free air compressor to offset the instantaneous surge in load caused by the change in intake status and ensure that the motor operating current is maintained within a safe threshold.

[0033] Preferably, the central decision module is also used to execute a timing feedforward control strategy, which adjusts the output torque of the power bypass module in advance before the valve action of the fluid valve array module. The generated total torque command is formed by superimposing a feedback term based on the exhaust pressure deviation and a feedforward term based on the timing event. The feedforward term includes a feedforward torque waveform function associated with the upcoming valve action event, which is used to adjust the compressor speed in advance to eliminate the pressure integral hysteresis effect before the valve action causes a sudden change in system flow resistance.

[0034] A second aspect of this invention provides a method for oxygen generation using an oil-free VPSA suspended air suspension based on multi-dimensional closed-loop control, comprising the following steps:

[0035] Ambient air is introduced into the power bypass module, the perception and reconstruction module collects fluid thermodynamic state data and constructs real-time intake air density parameters, and the central decision module performs load stabilization control based on the real-time intake air density parameters to drive the air-suspended oil-free air compressor to establish a work benchmark.

[0036] The perception and reconstruction module synchronously collects operating speed and pressure data, and generates real-time surge margin data based on the preset performance spectrum. The central decision module combines the real-time surge margin data with the process sequence status to construct the stability range determination result of the oxygen production system.

[0037] The central decision-making module dynamically monitors the real-time load status of the air-suspended oil-free air compressor based on the real-time intake air density parameter: when the intake air density increases and the load increases, it automatically corrects the upper limit of the operating speed or torque of the air-suspended oil-free air compressor downward to prioritize the stability of the input load.

[0038] At the adsorption process switching node, the central decision module performs feedforward control based on the valve action sequence, and generates a total torque command superimposed with the feedforward torque waveform to drive the power bypass module to adjust the output.

[0039] The fluid valve array module executes valve actions based on the reconstructed opening slope curve, completing gas separation and transfer under the direct connection architecture.

[0040] This invention provides an oil-free VPSA oxygen generation system and method based on multi-dimensional closed-loop control. It has the following beneficial effects:

[0041] 1. This invention addresses the challenge of fluid dynamic instability in direct-drive pressure swing adsorption (PSA) processes using air-suspension oil-free air compressors. It achieves dynamic matching of fluid impedance through the coordinated control of a power bypass module and a fluid valve array module. Utilizing closed-loop control logic based on real-time surge margin and its rate of change, a high-speed proportional unloading valve is driven to provide a venting channel when system impedance abnormally increases. Furthermore, by employing slope reconstruction technology, pressure shocks caused by valve action are mitigated, effectively suppressing fluid dynamic instability in the direct-drive system caused by process switching. This eliminates the volume redundancy of large buffer tanks while ensuring the safe operation of the air-suspension compressor across all operating conditions.

[0042] 2. This invention employs a thermal control buffer module in conjunction with dynamic and thermal interlock logic to solve the coupling interference problem between air circuit regulation and thermal circuit regulation under sensitive operating conditions. By forcibly freezing the state of the water pump and diverter valve at the edge of surge or in the sensitive locking interval of process switching, and utilizing the sensible heat capacity characteristics of the coolant buffer tank to bear the heat load fluctuation, it avoids additional air circuit disturbances caused by the action of the thermal control actuator, ensuring the thermodynamic boundary stability of the suspension bearing and high-speed motor under dynamic load, and extending the service life of the components.

[0043] 3. This invention utilizes a perception reconstruction module and a central decision-making module to achieve multi-dimensional feedforward and adaptive control, specifically implementing a load stabilization control strategy for load fluctuations caused by environmental changes. The system monitors intake air density and pressure parameters in real time. When it detects an increase in intake air density or pressure fluctuations that cause a sudden increase in the compressor's equivalent load, it can automatically correct the target speed downward or clamp the output torque, actively reducing the operating load. This effectively overcomes the motor overcurrent and inverter tripping faults that are prone to occur in traditional control methods under low temperature or high pressure intake conditions, greatly improving the continuous operation stability and reliability of the equipment under complex environmental conditions. Attached Figure Description

[0044] Figure 1 This is a system architecture diagram of the present invention;

[0045] Figure 2 This is a flowchart of the method steps of the present invention;

[0046] Figure 3 This is a process framework diagram of the central decision-making module of the present invention.

[0047] Among them, 100 is the power bypass module; 110 is the air-suspended oil-free air compressor; 111 is the high-speed permanent magnet motor; 112 is the suspension bearing assembly; 120 is the electronic bypass circuit; 121 is the high-speed proportional unloading valve; 200 is the thermal control buffer module; 210 is the process air cooling circuit; 220 is the equipment self-cooling circuit; 230 is the coolant buffer tank; 240 is the variable frequency water pump; 250 is the cooling fan; 260 is the three-way proportional diverter valve; 300 is the adsorption process module; 310 is the adsorption tower A; 320 is the adsorption tower B; 330 is the adaptive spring clamping device; 400 is the fluid valve array module; 410 is the tower top equalizing valve; 420 is the tower bottom equalizing valve; 430 is the single tower air replenishment valve; 500 is the perception reconstruction module; 510 is the inlet sensor group; 520 is the process sensor group; 530 is the vibration monitoring unit; and 600 is the central decision-making module. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] See attached document Figure 1 , Figure 1This is a system architecture diagram according to an embodiment of the present invention. The present invention provides an oil-free VPSA oxygen generation system based on multi-dimensional closed-loop control. This system adopts a direct-connection architecture without a buffer tank and achieves stable operation through coupled control of fluid thermodynamics and rotor dynamics. It includes a power bypass module 100, a thermal control buffer module 200, an adsorption process module 300, a fluid valve array module 400, a sensing and reconfiguration module 500, and a central decision-making module 600.

[0050] The power bypass module 100 includes an air-suspended oil-free air compressor 110 and an electronic bypass circuit 120. The air-suspended oil-free air compressor 110 integrates a high-speed permanent magnet motor 111 and a suspension bearing assembly 112. The electronic bypass circuit 120 is connected in parallel between the exhaust port of the air-suspended oil-free air compressor 110 and the process pipeline. A high-speed proportional unloading valve 121 is installed on the electronic bypass circuit 120, and the exhaust end of the high-speed proportional unloading valve 121 is connected to the atmospheric environment or a silencer. The electronic bypass circuit 120 is configured to open upon receiving an action command, releasing the fluid pressure in the pipeline through the high-speed proportional unloading valve 121.

[0051] The thermal control buffer module 200 is used for temperature control of the fluid medium and heat-generating equipment within the system. It includes a process gas-cooled circuit 210, an equipment self-cooling circuit 220, a coolant buffer tank 230, a variable frequency water pump 240, a cooling fan 250, and a three-way proportional flow divider valve 260. The process gas-cooled circuit 210 is equipped with a gas heat exchanger. The equipment self-cooling circuit 220 is equipped with a liquid-cooled flow channel. The coolant buffer tank 230 is connected in series in the circulation pipeline and contains a preset volume of cooling medium. The three-way proportional flow divider valve 260 is connected to the flow divider node between the process gas-cooled circuit 210 and the equipment self-cooling circuit 220.

[0052] The adsorption process module 300 includes adsorption tower A310 and adsorption tower B320, which alternately perform adsorption and desorption operations. Both adsorption tower A310 and adsorption tower B320 are equipped with adaptive spring clamping devices 330 at their tops. Both adsorption tower A310 and adsorption tower B320 are equipped with airflow distributors 340 at their bottoms. The airflow distributors 340 have conical flow-dividing chambers inside. The adsorption process described in this embodiment covers conventional pressure swing adsorption (PSA) and vacuum pressure swing adsorption (VPSA) processes, and its operating pressure range is designed according to the specific components to be separated.

[0053] The fluid valve array module 400 is responsible for controlling the airflow direction switching, including a top equalizing valve 410, a bottom equalizing valve 420, and a single-tower make-up air valve 430. The top equalizing valve 410 is connected between the top pipelines of adsorption tower A310 and adsorption tower B320. The bottom equalizing valve 420 is connected between the bottom pipelines of adsorption tower A310 and adsorption tower B320. The single-tower make-up air valve 430 is connected between the bottom pipeline of the adsorption tower and the atmospheric environment. The fluid valve array module 400 is directly connected via pipeline to the exhaust port of the air-suspension oil-free air compressor 110 and the inlet of the adsorption process module 300.

[0054] The perception and reconstruction module 500 is used to collect physical signals and calculate virtual state parameters, including an inlet sensor group 510, a process sensor group 520, and a vibration monitoring unit 530. The inlet sensor group 510 is located at the air inlet of the air-suspension oil-free air compressor 110. The process sensor group 520 is located inside adsorption towers A310 and B320 and in their piping. The vibration monitoring unit 530 is integrated into the suspension bearing assembly 112 or mounted on the casing surface. The perception and reconstruction module 500 is equipped with a computing unit.

[0055] The central decision-making module 600 is connected to each module via an industrial communication bus. It is configured to receive data from the sensing and reconstructing module 500 and send control commands to the power bypass module 100, the thermal control buffer module 200, and the fluid valve array module 400. The central decision-making module 600 internally stores and executes the load stabilization control algorithm, dynamic and thermal interlock logic, and timing feedforward control strategy.

[0056] See attached document Figure 2 and attached Figure 3 , Figure 2 This is a flowchart of a method according to an embodiment of the present invention. The present invention provides an oxygen production method based on multi-dimensional closed-loop control, comprising the following steps:

[0057] S10, ambient air is introduced into the power bypass module 100. The inlet sensor group 510 in the perception and reconstruction module 500 collects fluid thermodynamic state data and constructs real-time intake air density parameters. The central decision module 600 executes the load stabilization control algorithm based on the real-time intake air density parameters and intake air pressure parameters, generates dynamic speed limit commands or torque clamping thresholds for the air-suspended oil-free air compressor 110, and drives the high-speed permanent magnet motor 111 to establish a work reference within the safe current range to prevent equipment overload caused by increased intake air load.

[0058] S20, while the air-suspended oil-free air compressor 110 is running, the sensing and reconstruction module 500 synchronously collects its operating speed and outlet pressure data, maps the real-time operating point to the preset compressor performance spectrum, and calculates and generates real-time surge margin data; the central decision module 600 receives the real-time surge margin data and passes it through the current process timing state logic to construct the system stability interval determination result;

[0059] S30, the central decision-making module 600 drives the thermal control buffer module 200 to execute thermal control strategies based on the stability judgment results: when the judgment result is in the high surge margin stable range, a PID adjustment command is generated to drive the variable frequency water pump 240 and the three-way proportional diverter valve 260 to perform active temperature control; when the judgment result points to the pressure equalization switching sequence or the low surge margin sensitive range, a lock command is generated to force the thermal control buffer module 200 to stop the active adjustment action, and the heat load is carried by the pre-stored medium heat capacity in the coolant buffer tank 230.

[0060] S40, after being treated by the thermal boundary, the airflow enters the fluid valve array module 400 and is guided to the adsorption process module 300. The airflow is rectified by the airflow distributor 340 inside the adsorption tower A310 or adsorption tower B320 and then pushes the molecular sieve bed to carry out separation. After separation, the oxygen-rich gas flows through the adaptive spring clamping device 330 and is discharged.

[0061] S50, at the adsorption process switching node, the central decision module 600 constructs a pipeline pressure change prediction model based on the timing of the valve action to be executed, outputs the pressure change amount as a feedforward torque command, and drives the power bypass module 100 to adjust the output torque; simultaneously extracts the historical vibration characteristic values ​​fed back by the vibration monitoring unit 530, and reconstructs the opening slope curve of each regulating valve in the fluid valve array module 400 based on the characteristic values.

[0062] S60, if the real-time surge margin data calculated by the perception and reconstruction module 500 falls below the set critical safety threshold, the central decision module 600 generates a bypass release command, which drives the high-speed proportional unloading valve 121 of the power bypass module 100 to open, and physically changes the pipeline impedance to force the oil-free air compressor 110 to return to the safe operating point.

[0063] See attached document Figure 1 and attached Figure 3 The power bypass module 100 consists of an air-suspended oil-free air compressor 110 and an electronic bypass circuit 120.

[0064] The air-suspended oil-free air compressor 110 adopts an integrated direct-drive structure. Its driving component is a high-speed permanent magnet motor 111. The stator winding of the high-speed permanent magnet motor 111 directly drives the rotor shaft system to rotate. Centrifugal impellers are fixed at both ends of the rotor shaft system. In different embodiments of the present invention, the support structure of the rotor shaft system is a suspension bearing assembly 112. Regarding the suspension bearing assembly 112:

[0065] Example 1: Applicable to high-power, high-tonnage PSA / VPSA oxygen generation systems. The components include radial magnetic bearings, axial magnetic bearings, and displacement sensors. The rotor is suspended through five-degree-of-freedom active electromagnetic control, and features adjustable stiffness and active vibration damping.

[0066] Example 2: Applicable to compact small-to-medium-sized PSA / VPSA systems. The components employ hydrodynamic foil bearings, utilizing the film hydrodynamic effect generated by the high-speed rotation of the rotor to achieve non-contact support, eliminating the need for complex electromagnetic controllers and simplifying the structure. Regardless of the suspension method used, the air-suspension oil-free air compressor 110 in this example is designed to have high dynamic response characteristics, with its motor controller's torque response time set to the millisecond level to adapt to the timing feedforward control strategy.

[0067] The exhaust port of the air-suspension oil-free air compressor 110 is directly connected to the inlet of the downstream fluid valve array module 400 via a rigid pipe. In this connection path, no process buffer tank is provided for buffering airflow pulsations or storing compressed gas. Specifically, the pipe volume between the compressor exhaust port and the adsorption tower inlet is less than a preset pressure-stabilizing volume threshold, allowing changes in airflow pressure within the pipe to be directly and quickly coupled to the compressor outlet without significant pressure integral hysteresis.

[0068] To address the compressor surge issue that may be caused by sudden changes in pipeline impedance under a direct-connect architecture, an electronic bypass circuit 120 is connected in parallel to the exhaust pipe of the air-suspended oil-free air compressor 110, specifically located upstream of the exhaust port check valve. The inlet end of the electronic bypass circuit 120 is connected to the main exhaust line, and the outlet end is connected to the atmospheric environment. A silencer is installed at the outlet end to reduce noise during airflow release.

[0069] The actuator of the electronic bypass circuit 120 is a high-speed proportional unloading valve 121, which has the ability to continuously adjust the flow cross-sectional area, and the full stroke response time of the valve core is less than one cycle time when the compressor surges. The high-speed proportional unloading valve 121 is configured as a controlled variable impedance element to provide a low-impedance fluid venting path when an abnormal increase in system impedance is detected.

[0070] In practical implementation, the opening control of the high-speed proportional unloading valve 121 follows impedance dynamic matching logic. When the system determines that it is on the edge of surge, the opening of the valve is adjusted accordingly. The control is adjusted based on the real-time surge margin and its rate of change. The control action follows a continuous adjustment law:

[0071] ;

[0072] In the formula, This indicates that the high-speed proportional unloading valve 121 is in The opening degree command at any given time has a value range of 0 to 100%. This is a saturation function, limiting the output to within the valve's physical opening range; The surge margin is calculated in real time by the system; The preset safety surge margin threshold; This is the proportional gain coefficient, used to set the response strength to the degree of surge approximation; This is the differential gain coefficient, used to set the damping for suppressing surge deterioration rate; The time derivative of surge margin represents the trend of deterioration in operating conditions.

[0073] This control logic is executed as a high-frequency interrupt task in the local controller of the power bypass module 100 or the central decision module 600. When the switching of the adsorption tower causes a momentary increase in downstream flow resistance, if the feedforward control fails to completely offset the pressure peak, the high-speed proportional unloading valve 121 can quickly open to the corresponding opening degree according to the above formula. By connecting a variable load in parallel at the compressor outlet, the volumetric flow rate through the compressor is artificially increased, thereby forcing the compressor's operating point to move to the lower right, away from the surge boundary line in the upper left of the compressor performance graph. After the pipeline pressure fluctuation subsides, rebounded to After the above, the high-speed proportional unloading valve 121 automatically and smoothly closes according to the formula calculation results, restoring the system to full-flow direct-connection gas supply state.

[0074] The thermal control buffer module 200 constructs a liquid-cooled thermal management subsystem independent of the gas circulation path. This thermal control buffer module 200 includes a closed-loop piping network for cooling medium storage, power circulation, flow distribution, and heat exchange. The cooling medium flowing in this closed-loop piping network is typically deionized water or an aqueous ethylene glycol solution, to balance specific heat capacity and antifreeze performance.

[0075] The circulating power source for the thermal control buffer module 200 is provided by the variable frequency water pump 240. The outlet pipe of the variable frequency water pump 240 is connected to the inlet port of the three-way proportional flow divider valve 260. The three-way proportional flow divider valve 260 has two outlet ports, which are respectively connected to the inlet of the process air cooling circuit 210 and the inlet of the equipment self-cooling circuit 220. The process air cooling circuit 210 includes a gas heat exchanger located downstream of the exhaust of the air-suspended oil-free air compressor 110. This gas heat exchanger adopts a shell-and-tube or plate-fin structure to transfer the heat of compression of the compressed air to the cooling medium. The equipment self-cooling circuit 220 includes a stator cooling water jacket and a heat dissipation plate for the motor controller integrated within the housing of the air-suspended oil-free air compressor 110 to remove copper losses, iron losses, and switching losses of the power devices. After the return pipes of the process air cooling circuit 210 and the equipment self-cooling circuit 220 merge, the flow passes through the air-cooled radiator of the cooling fan 250 and finally returns to the suction side of the variable frequency water pump 240.

[0076] A coolant buffer tank 230 is connected in series on the return or intake main of the aforementioned circulation loop. The coolant buffer tank 230 is configured to have a preset volume. The insulated fluid container, coolant buffer tank 230, is configured as a thermal inertial generator, its volume The design is based on matching the system's maximum allowable rate of temperature rise with the amplitude of heat load fluctuations. When the system control logic enters a dynamic-thermal interlock state and stops active regulation, this component utilizes the sensible heat capacity of the storage medium to absorb or release heat, thereby smoothing out temperature fluctuations.

[0077] Specifically, the thermal inertia principle of the coolant buffer tank 230 can be described by the thermodynamic balance equation. When the system is in a locked regulation state, the heat dissipation capacity of the cooling system is fixed, and the fluid temperature is... Over time The rate of change depends on the total heat capacity of the system:

[0078] ;

[0079] In the formula, The total heat load power input to the system, including compression heat and motor losses; Indicates fluid temperature Over time The rate of change; The heat dissipation power discharged by the radiator is approximately constant or a slow variable in the locked state; The density of the cooling medium; This refers to the specific isobaric heat capacity of the cooling medium. This refers to the inherent fluid volume within the pipelines and heat exchangers; The effective volume of the coolant buffer tank 230.

[0080] By setting to meet The coolant buffer tank 230, with its specific conditions, increases the total system heat capacity in the denominator, thus ensuring that even during sensitive periods when the control system suspends adjustment of the variable frequency water pump 240 and the three-way proportional flow divider valve 260, the system can maintain its heat capacity. Fluctuations occur, the rate of change of fluid temperature It is still limited to an extremely low range, thus ensuring that the gas temperature entering the adsorption tower and the motor stator temperature do not undergo a sudden change, achieving passive steady-state maintenance without active control intervention.

[0081] The three-way proportional flow divider valve 260 and the variable frequency water pump 240, acting as thermal control actuators, possess dual-mode response characteristics. In normal mode, both receive continuous PID control signals based on temperature deviation, changing the total flow rate and flow ratio in real time. In lockout mode, their internal controllers or drivers can respond to upper-level commands, freezing the current opening position and operating frequency to maintain a constant output state. This hardware configuration, combined with the thermal inertia physical characteristics of the coolant buffer tank 230, forms the basis for the implementation of the dynamic-thermal interlock logic.

[0082] The adsorption process module 300 consists of two or more sets of adsorption vessels operating in parallel, namely adsorption tower A310 and adsorption tower B320. Each adsorption tower is a vertical cylindrical pressure vessel filled with zeolite molecular sieves for selective adsorption of nitrogen and activated alumina for water removal. The adsorption process module 300 is configured to directly receive the pulsating airflow from the air-suspension oil-free air compressor 110 in the absence of an upstream buffer tank, and maintain bed stability through the adaptive characteristics of its internal mechanical structure.

[0083] Both adsorption towers A310 and B320 have integrated airflow distributors 340 at their bottom inlets. Designed to accommodate high-velocity inlet flow in a direct-connection architecture, the airflow distributor 340 incorporates an inverted conical flow-dividing chamber. The cross-sectional area of ​​this chamber gradually increases along the airflow direction, converting the high-speed axial jet from the compressor outlet into a low-speed radial laminar flow. Several unevenly distributed guide holes are formed on the sidewall of the conical flow-dividing chamber, with the hole diameter gradually increasing from bottom to top. This variable-diameter design ensures that the mass flow rate density at each point in the cross-section at the bottom of the molecular sieve bed tends to be uniform. The presence of the airflow distributor 340 reduces the direct momentum impact of the airflow on the adsorbent particles, acting as a fluid dynamic rectifier.

[0084] Both adsorption towers A310 and B320 are equipped with adaptive spring clamping devices 330 at their tops. These devices are configured as passive mechanical feedback mechanisms to handle pressure fluctuations generated during pressure equalization and adsorption switching in the unbuffered direct-connected system. The adaptive spring clamping device 330 mainly consists of a permeable clamping plate, a guide rod, a high-stiffness helical spring, and a sealing end cap. The permeable clamping plate covers the top of the molecular sieve bed and can slide freely along the axial direction of the adsorption tower. The high-stiffness helical spring is pre-compressed and installed between the permeable clamping plate and the sealing end cap, applying a constant axial preload to the permeable clamping plate.

[0085] The adaptive spring compaction device 330 can dynamically adjust the compaction state of the bed according to changes in the gas pressure inside the tower. When the gas flows from bottom to top and the pressure increases, the molecular sieve bed tends to expand upward; when the gas flow reverses or the pressure decreases, the bed tends to settle. The adaptive spring compaction device 330 absorbs the slight deformation of the bed through the extension and contraction displacement of the spring, and its mechanical equilibrium state follows the following dynamic relationship:

[0086] ;

[0087] In the formula, This refers to the real-time clamping force applied to the top of the molecular sieve bed; is the stiffness coefficient of the helical spring; This is the initial pre-compression of the spring; This represents the axial displacement of the ventilated clamping plate relative to its initial position (positive for downward displacement). The pressure difference between the upper and lower sides of the ventilated pressing plate fluctuates drastically with the flow rate and direction of the process airflow. This refers to the effective force-bearing area of ​​the breathable clamping plate; For the quality of the breathable clamping plate and related connecting parts; This is the acceleration due to gravity.

[0088] By setting a sufficiently large initial pre-compression amount and the selection of high stiffness coefficient The springs ensure that the system is in operation under any conditions. The pressure is always greater than zero and maintained within the preset effective compression range. This ensures that even during adsorption switching when the pressure fluctuates greatly in the direct connection system, the molecular sieve particles remain in close contact, preventing pulverization failure caused by particle boiling or mutual friction.

[0089] The fluid valve array module 400 is located adjacent to the adsorption process module 300 and is used to minimize the dead space volume between the valve and the adsorption tower. The fluid valve array module 400 consists of an actuator with analog quantity adjustment capability, which is used to accurately control the flow direction and flow rate of the gas in stepless adjustment mode, thereby achieving dynamic matching of fluid impedance in a direct connection architecture without physical buffer tank.

[0090] The fluid valve array module 400 includes a tower top equalizing valve 410, a tower bottom equalizing valve 420, and a single-tower gas supply valve 430. These valves are configured as electrically controlled valves. Specifically, these control valves are equipped with high-precision electric actuators and position feedback units, capable of receiving standard analog control signals of 4-20mA or 0-10V, achieving continuous opening adjustment across the entire stroke range from 0% to 100%. The valve body structure preferably employs a V-type ball valve or butterfly valve to possess corrected equal percentage flow characteristics or linear flow characteristics, ensuring a defined functional relationship between valve opening changes and changes in the flow rate passing through the valve.

[0091] The top equalizing valve 410 is connected to the top outlet pipes of adsorption tower A310 and adsorption tower B320 respectively, and is used to control the rate at which oxygen-enriched gas in the high-pressure tower transfers to the low-pressure tower during the equalizing step. The bottom equalizing valve 420 is connected to the bottom inlet pipes of both towers respectively, and is used to assist in pressure balance at the bottom. One end of the single-tower gas supply valve 430 is connected to the main gas inlet pipe at the bottom of the adsorption tower, and the other end is connected to the atmosphere or a specific process exhaust port, and is used to adjust the gas release flow rate or introduce backflushing gas during the cleaning or exhaust steps.

[0092] The fluid valve array module 400 executes an action strategy based on opening slope reconstruction. Since there is no large-capacity buffer tank in the system to absorb pressure surges, the valve opening process follows a specific time-opening trajectory. This trajectory control allows the valve to act as a variable-damping, variable-throttling element during opening, actively suppressing the rate of pressure rise or fall in the pipeline by controlling the rate of change of the valve's flow cross-sectional area.

[0093] Specifically, the real-time flow area of ​​each regulating valve in the fluid valve array module 400 and the response relationship with the control command are designed to coordinate with the feedforward control logic. The instantaneous opening command of any regulating valve (taking the tower top equalizing valve 410 as an example) during its operation... The trajectory generation function follows the definition below:

[0094] ;

[0095] in, The basic opening slope function describes the opening path of the valve under ideal, undisturbed conditions, and is typically defined as:

[0096] ;

[0097] In the formula, This is the starting moment of the action; The moment the action is completed; The base slope coefficient is determined by the cycle time of the process. For shape factor, when When linear opening, when The valve opens in a parabolic or exponential manner to match its own flow characteristic curve. This is a correction term based on mechanical vibration feedback, used to fine-tune the opening to suppress fluid noise at a specific frequency.

[0098] In the initial pressure equalization phase, the fluid valve array module 400 limits the initial impulsive airflow with a small valve opening. As the pressure difference decreases, the valve opening gradually increases according to the aforementioned function, maintaining a relatively constant flow rate. This ensures a smooth and controllable gas transfer process between different pressure vessels in a direct-connect system, effectively supporting stable system operation under conditions without physical buffering.

[0099] The sensing and reconstruction module 500 covers a physical field monitoring network from the gas source inlet to the working components. This module not only includes physical sensors but also integrates an embedded computing unit for executing state observer algorithms, reconstructing discrete, one-dimensional physical signals into high-dimensional state parameters that reflect the system's thermodynamic boundaries and dynamic stability.

[0100] The perception reconstruction module 500 includes an inlet sensor group 510, a process sensor group 520, and a vibration monitoring unit 530. The inlet sensor group 510 is installed downstream of the intake filter or in the intake manifold of the air-suspended oil-free air compressor 110, and includes a resistance thermometer and a piezoresistive pressure transmitter to collect the thermodynamic parameters of uncompressed ambient air. The process sensor group 520 is distributed in the internal bed layers and inlet / outlet pipe nodes of adsorption towers A310 and B320, configured as high-frequency pressure sensors with millisecond-level response times to capture the pressure waveform during adsorption switching. The vibration monitoring unit 530 is integrated inside the suspension bearing controller of the air-suspended oil-free air compressor 110, using a magnetic bearing position sensor probe to monitor the micron-level displacement signals of the rotor shaft system in the axial and radial directions in real time, or by adding a piezoelectric accelerometer to the casing surface to pick up the high-frequency vibration intensity.

[0101] The computing unit within the perception reconstruction module 500 executes a virtual sensing algorithm based on the acquired physical signals, with the real-time intake air density as the calculation parameter. Since the oxygen production efficiency of the VPSA oxygen generation system is directly related to the atomic mass flow rate of oxygen entering the system, while volumetric or dynamic compressors only provide volumetric flow rate, real-time intake air density is needed to calibrate the actual mass load. The computing unit calculates the real-time intake air density using a modified form of the gas law, based on the real-time acquired inlet pressure and inlet temperature. :

[0102] ;

[0103] In the formula, Let be the intake air density at time t; The absolute pressure collected by the inlet sensor group 510; The thermodynamic temperature collected by the inlet sensor group 510; This is the specific gas constant for moist air, which is corrected by combining the standard dry air gas constant with the ambient relative humidity. The gas compressibility factor is approximately 1 under normal pressure intake conditions, but is nonlinearly corrected using a lookup table method under extreme temperatures. This real-time intake density parameter is output to the central decision module 600 as a feedforward input variable for the load stability control algorithm.

[0104] The perception reconstruction module 500 performs real-time surge margin reconstruction. In the direct-drive architecture, due to the lack of a buffer tank for pressure stabilization, the compressor back pressure fluctuates drastically with the adsorption process. To quantify the proximity of the current operating point to the hydrodynamic instability boundary, the computing unit stores the inherent performance spectrum of the air-suspended oil-free air compressor 110, which defines the surge boundary line at different speeds. The computing unit maps the real-time collected exhaust pressure, intake pressure, and speed to this performance spectrum to calculate the dimensionless real-time surge margin. :

[0105] ;

[0106] In the formula, This represents the real-time surge margin; the smaller the value, the closer it is to the surge state. To achieve real-time operating pressure ratio, the ratio of the exhaust pressure collected by the process sensor group 520 to the intake pressure collected by the inlet sensor group 510 is calculated. The corrected speed is derived from the real-time physical speed based on the intake air temperature. The surge boundary function represents the boundary function at a specific corrected rotational speed. The critical pressure ratio at which the compressor is about to surge is calculated. This function is constructed in the memory of the computing unit through polynomial fitting or lookup table interpolation.

[0107] The signal output by the vibration monitoring unit 530 is processed into frequency domain feature values. The arithmetic unit performs a fast Fourier transform on the original vibration waveform to extract the amplitude features related to the rotational frequency and its harmonics. When asynchronous vibration components or energy surges in a specific frequency band are detected, the amplitude features are marked as precursors to fluid-induced vibration and sent as correction factors to the slope control logic of the fluid valve array module 400.

[0108] The central decision-making module 600 consists of a high-performance industrial control computer or an embedded programmable automation controller. This central decision-making module 600 establishes bidirectional data connections with the power bypass module 100, thermal control buffer module 200, fluid valve array module 400, and sensing and reconstructing module 500 via a deterministic industrial real-time Ethernet communication bus. The central decision-making module 600 internally runs a real-time operating system and is configured to execute multi-threaded control tasks, including load stabilization control algorithms, dynamic and thermal interlock logic, and timing feedforward control strategies.

[0109] The central decision-making module 600 executes a load stabilization control algorithm. In this embodiment, the central decision-making module 600 receives real-time intake density parameters from the perception reconstruction module 500. Based on this, the target speed or torque limit of the air-suspended oil-free air compressor 110 is dynamically adjusted. This adjustment logic follows the following inverse load correction function:

[0110] ;

[0111] In the formula, This is the maximum safe speed allowed under the current operating conditions (or the corrected target speed); This refers to the rated speed under standard operating conditions. The design reference air density; The intake air density is monitored in real time; The load sensitivity coefficient ranges from 0.5 to 1.0, depending on the aerodynamic characteristics of the impeller. This is a derating factor based on the motor coil temperature (1 when the temperature is normal).

[0112] Based on the above logic, when the system detects a significant increase in intake air density (such as during a cold start in winter or high-pressure intake) leading to a sudden increase in load, the central decision module 600 will automatically reduce the operating speed. By sacrificing a small amount of volumetric flow rate, priority is given to ensuring that the motor current is maintained within the rated range, thus achieving "speed reduction and stability maintenance" and effectively avoiding equipment overcurrent faults caused by dynamic load changes.

[0113] To address the conflict between gas path pressure fluctuations and thermal path regulation lag in a direct-connect architecture, the central decision module 600 executes dynamic and thermal interlock logic, dividing the system's operating state into a "stable regulation range" and a "sensitive lock-in range." The central decision module 600 monitors the real-time surge margin output by the sensing and reconfiguration module 500 in real time. The system's current timing step state is also considered. The system is deemed to have entered a "sensitive lockout zone" when any of the following conditions are met:

[0114] Real-time surge margin Below the preset adjustment lockout threshold ;

[0115] Before the adsorption process enters the equalization or switching step Within seconds.

[0116] Once the system enters the "sensitive lockout range," the central decision module 600 immediately sends a "state freeze" command to the thermal control buffer module 200. This command forces the variable frequency water pump 240 to maintain its current speed and locks the current opening of the three-way proportional flow divider valve 260, suspending the PID control action based on temperature feedback. At this time, the system utilizes the thermal inertia of the coolant buffer tank 230 to maintain the relative stability of the thermodynamic boundary, preventing fluctuations in the heat exchanger outlet temperature caused by rapid changes in cooling water flow rate or direction, which could lead to sudden changes in intake air density and induce compressor operating point drift. When the system returns to the "stable adjustment range," the thermal control logic automatically unlocks, resuming active closed-loop control of the target temperature.

[0117] To handle pressure surges in the tankless direct-drive architecture, the central decision module 600 executes a time-based feedforward control strategy. This strategy leverages the periodicity and determinism of the VPSA process flow, pre-adjusting the output torque of the air-suspended oil-free air compressor 110 before the valves in the fluid valve array module 400 actuate. The central decision module 600 generates a total torque command. It is composed of the superposition of feedback and feedforward terms:

[0118] ;

[0119] In the formula, This is the final torque command sent to the motor controller; The output is a conventional PID feedback control based on exhaust pressure deviation; The target adsorption pressure set for the process; Real-time exhaust pressure; This represents the total number of valve action events that are about to occur. For the first The predetermined trigger time for a valve action (such as the opening of a pressure equalizing valve); In order to be with the first Feedforward torque waveform function associated with each event.

[0120] The feedforward torque waveform function They are typically designed as Gaussian pulses or trapezoidal waves that are opposite to the pressure surge waveform. For example, before the equalizing valve opens, causing a momentary decrease in system flow resistance and a pressure drop, the feedforward term... By increasing the motor torque in advance, the compressor is pre-accelerated. This time-deterministic feedforward compensation eliminates the lag of conventional pressure feedback control, limits pressure fluctuations in the direct-drive system to a safe range, and ensures the pressure stability of the molecular sieve bed.

[0121] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An oil-free VPSA oxygen generation system based on multi-dimensional closed-loop control, characterized in that, include: The perception and reconstruction module is used to collect physical field signals and reconstruct virtual state parameters that reflect the thermodynamic and dynamic state of the system using algorithms. The central decision-making module is used to calculate and generate multi-dimensional coupled control commands based on the virtual state parameters as input. The multi-dimensional coupled control commands are adapted to different pressure domain control strategies of pressure swing adsorption or vacuum pressure swing adsorption. The power bypass module includes an air-suspended oil-free air compressor and an electronic bypass circuit connected in parallel to the exhaust pipe of the air-suspended oil-free air compressor. The actuator of the electronic bypass circuit is a high-speed proportional unloading valve. The power bypass module is used to adjust the operating conditions of the air-suspended oil-free air compressor in response to the multi-dimensional coupling control command and to build a fluid work benchmark under the direct connection architecture. The thermal control buffer module is used to execute dynamic and thermal interlock logic based on the multidimensional coupling control command, and to construct a stable thermodynamic boundary by utilizing the thermal capacity inertia of the coolant buffer tank. The fluid valve array module includes a tower top equalizing valve, a tower bottom equalizing valve, and a single tower gas supply valve. The fluid valve array module is used to perform opening slope reconstruction according to the multi-dimensional coupling control command and to perform impedance dynamic matching on the gas flow output by the fluid work reference to be compatible with the fluid conduction characteristics under normal pressure or vacuum pressure transformation environment. The adsorption process module receives the matched airflow through an airflow distributor and performs gas separation using an adaptive spring clamping device.

2. The air-suspension oil-free VPSA oxygen generation system based on multi-dimensional closed-loop control according to claim 1, characterized in that, The air-suspension oil-free air compressor adopts an integrated direct-drive structure. The internally integrated high-speed permanent magnet motor supports the rotor shaft system through a suspension bearing assembly, and the exhaust port is directly connected to the inlet of the downstream fluid valve array module through a rigid pipe. The electronic bypass circuit is connected in parallel to the exhaust pipe of the air-suspended oil-free air compressor. The actuator is a high-speed proportional unloading valve, which is a controlled variable impedance element used to provide a low-impedance fluid discharge channel when an abnormal increase in system impedance is detected. The opening control of the high-speed proportional unloading valve follows the impedance dynamic matching logic. The opening command is adjusted based on the real-time surge margin and the rate of change. When the system determines that it is on the edge of surge, the opening of the high-speed proportional unloading valve is calculated by the difference between the proportional gain coefficient acting on the safe surge margin threshold and the real-time surge margin, and by combining the differential gain coefficient acting on the time derivative of the surge margin. This is used to move the operating point of the air-suspended oil-free air compressor to a region far away from the surge boundary line.

3. The air-suspension oil-free VPSA oxygen generation system based on multi-dimensional closed-loop control according to claim 1, characterized in that, The thermal control buffer module includes a variable frequency water pump, a three-way proportional flow divider valve, and a coolant buffer tank connected in series in the circulation pipeline. The coolant buffer tank is an insulated fluid container with a preset volume, specifically an insulated fluid container with a preset volume, the volume of which is designed to match the maximum allowable temperature rise rate and the amplitude of heat load fluctuation. The central decision module is used to execute the dynamic and thermal interlock logic, which divides the oxygen production system's operating state into a stable adjustment range and a sensitive locking range. When the real-time surge margin is lower than the preset adjustment lockout threshold or the process sequence is about to enter the pressure equalization step, it is determined that the sensitive locking range has been entered. Within the sensitive locking range, the central decision module generates a state freeze command, forcing the variable frequency water pump to maintain its current speed and locking the current opening of the three-way proportional flow divider valve. At this time, the coolant buffer tank absorbs or releases heat by utilizing the sensible heat capacity of the storage medium, limiting the rate of change of fluid temperature over time and maintaining a relatively stable thermodynamic boundary.

4. The air-suspension oil-free VPSA oxygen generation system based on multi-dimensional closed-loop control according to claim 1, characterized in that, The adsorption process module includes adsorption tower A and adsorption tower B operating in parallel: Each adsorption tower has an integrated airflow distributor at its bottom inlet. The airflow distributor has an inverted conical diversion chamber inside. The sidewall of the conical diversion chamber has guide holes with gradually increasing diameters from bottom to top, which are used to convert the high-speed axial jet into a low-speed radial laminar flow and distribute it evenly to the molecular sieve bed. Each adsorption tower is equipped with an adaptive spring clamping device at the top. The adaptive spring clamping device is configured as a passive mechanical feedback mechanism. It applies axial pre-tightening force to the air-permeable clamping plate through a high-stiffness helical spring and uses the extension and retraction displacement of the spring to absorb the slight deformation of the bed caused by the pressure fluctuation of the direct connection system, so as to ensure that the real-time clamping force applied to the top of the molecular sieve bed is maintained within the effective clamping range. The adsorption process module performs gas separation using pressure swing adsorption or vacuum pressure swing adsorption.

5. The air-suspension oil-free VPSA oxygen generation system based on multi-dimensional closed-loop control according to claim 1, characterized in that, The fluid valve array module is used to perform opening slope reconstruction. The instantaneous opening command when the valve moves follows a preset trajectory generation function. The trajectory generation function is composed of a basic opening slope function and a correction term based on mechanical vibration feedback. The basic opening slope function is determined based on the process cycle time and shape factor, so that the valve acts as a variable throttling element with variable damping during the opening process.

6. The air-suspension oil-free VPSA oxygen generation system based on multi-dimensional closed-loop control according to claim 1, characterized in that, The perception reconstruction module includes an inlet sensor group arranged at the air inlet, and the computing unit within the perception reconstruction module is used to execute a virtual sensing algorithm to reconstruct the real-time air intake density parameters. The computing unit calculates the real-time intake density parameters based on the absolute pressure and thermodynamic temperature collected by the inlet sensor group and using the gas state equation, which includes corrections for gas compressibility factor and humid air-to-gas ratio constant.

7. The air-suspension oil-free VPSA oxygen generation system based on multi-dimensional closed-loop control according to claim 6, characterized in that, The sensing and reconstruction module includes a group of process sensors distributed in the adsorption tower and pipelines, and the computing unit is also used to reconstruct the real-time surge margin based on a preset compressor performance spectrum. The computing unit maps the real-time operating pressure ratio, calculated from the ratio of exhaust pressure to intake pressure collected by the process sensor group, and the reduced speed, which is obtained by correcting the real-time physical speed based on the intake temperature, onto the compressor performance map that defines the surge boundary line, and calculates and generates a real-time surge margin that represents the degree to which the current operating point approaches the hydrodynamic instability boundary.

8. The air-suspension oil-free VPSA oxygen generation system based on multi-dimensional closed-loop control according to claim 1, characterized in that, The central decision module is used to execute the load stabilization control algorithm. Based on the received real-time intake density and intake pressure parameters, it dynamically monitors the real-time load status of the air-suspended oil-free air compressor. When the real-time intake density or intake pressure increases, causing the load to increase instantaneously, the central decision module generates a speed derating command or a torque clamping command to actively reduce the target speed or output torque of the air-suspended oil-free air compressor to offset the instantaneous load surge caused by the change in intake status and ensure that the motor operating current is maintained within the safe threshold.

9. The air-suspension oil-free VPSA oxygen generation system based on multi-dimensional closed-loop control according to claim 1, characterized in that, The central decision-making module is also used to execute a timing feedforward control strategy, which adjusts the output torque of the power bypass module in advance before the valve action of the fluid valve array module. The generated total torque command is formed by superimposing a feedback term based on the exhaust pressure deviation and a feedforward term based on the timing event. The feedforward term includes a feedforward torque waveform function associated with the upcoming valve action event, which is used to adjust the compressor speed in advance to eliminate the pressure integral hysteresis effect before the valve action causes a sudden change in system flow resistance.

10. An oil-free VPSA oxygen generation method based on multi-dimensional closed-loop control, applied to the oil-free VPSA oxygen generation system based on multi-dimensional closed-loop control as described in any one of claims 1-9, characterized in that, Includes the following steps: Ambient air is introduced into the power bypass module, the perception and reconstruction module collects fluid thermodynamic state data and constructs real-time intake air density parameters, and the central decision module performs load stabilization control based on the real-time intake air density parameters to drive the air-suspended oil-free air compressor to establish a work benchmark. The perception and reconstruction module synchronously collects operating speed and pressure data, and generates real-time surge margin data based on the preset performance spectrum. The central decision module combines the real-time surge margin data with the process sequence status to construct the stability range determination result of the oxygen production system. The central decision-making module dynamically monitors the real-time load status of the air-suspended oil-free air compressor based on the real-time intake air density parameter: when the intake air density increases and the load increases, it automatically corrects the upper limit of the operating speed or torque of the air-suspended oil-free air compressor downward to prioritize the stability of the input load. At the adsorption process switching node, the central decision module performs feedforward control based on the valve action sequence, and generates a total torque command superimposed with the feedforward torque waveform to drive the power bypass module to adjust the output. The fluid valve array module executes valve actions based on the reconstructed opening slope curve, completing gas separation and transfer under the direct connection architecture.

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