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CN-121983615-A - Air supply device and method for cathode closed galvanic pile or methanol fuel cell

CN121983615ACN 121983615 ACN121983615 ACN 121983615ACN-121983615-A

Abstract

The invention discloses an air supply device and method for a cathode closed galvanic pile or a methanol fuel cell. The device comprises a high-speed brushless direct current motor, a centrifugal impeller directly driven by the high-speed brushless direct current motor, a volute casing for packaging the impeller and an electronic control unit. The impeller and the volute are pneumatically optimized, so that the device has high efficiency and wide stable working area under the back pressure of 1-10 kPa. The electronic control unit takes the load current of the pile as a main feedforward signal, rapidly sets the target rotating speed of the motor through a built-in mapping table, and realizes accurate tracking by adopting a rotating speed closed loop. The control unit is integrated with self-learning compensation, anti-disturbance quick response, safety protection, anti-integral saturation and other mechanisms. The invention solves the severe requirements of the miniaturized fuel cell system on high back pressure, quick response, small volume and long service life of the air supply component.

Inventors

  • GU JIAFENG
  • YU HUALIN
  • YANG KUN
  • YANG HAO
  • XIANG MIN

Assignees

  • 四川轻绿科技有限公司

Dates

Publication Date
20260505
Application Date
20260408

Claims (10)

  1. 1. The air supply device for the cathode closed galvanic pile or the methanol fuel cell is characterized by comprising a brushless direct current motor (1), a high-speed centrifugal impeller (2) and an electronic control unit (3), wherein the high-speed centrifugal impeller (2) and the electronic control unit (3) are respectively connected with the brushless direct current motor (1), the brushless direct current motor (1) drives the high-speed centrifugal impeller (2) to rotate, the high-speed centrifugal impeller (2) is packaged in a volute (4), and the volute (4) is provided with a gas flow passage (5); The electronic control unit (3) outputs a PWM signal to the brushless direct current motor (1), the PWM signal is used for controlling the rotating speed of the brushless direct current motor (1), the electronic control unit receives load current from the fuel cell system, the duty ratio of the PWM signal is dynamically adjusted, and the rotating speed of the brushless direct current motor (1) is adjusted through the duty ratio of the PWM signal.
  2. 2. The air supply device for a cathode closed cell stack or a methanol fuel cell according to claim 1, wherein the high-speed centrifugal impeller (2) adopts backward curved blades, and the volute (4) adopts an unequal base circle logarithmic spiral line or a double-arc divergent structure; The high-speed centrifugal impeller (2) and the volute (4) are obtained through ternary flow theory optimization, so that the device has the highest static pressure efficiency point and a widened high-efficiency working area in the back pressure range of 1kPa to 10 kPa; the rated no-load rotating speed of the brushless direct current motor (1) is not lower than 80000 rpm; The preset minimum safe rotating speed of the brushless direct current motor (1) in the electronic control unit (3) is 20000 rpm; a spiral flow passage structure is arranged between an air inlet of the high-speed centrifugal impeller (2) and the volute (4), and an axial clearance between the top of the high-speed centrifugal impeller (2) and the volute (4) is less than 0.5% of the diameter of the high-speed centrifugal impeller (2).
  3. 3. The air supply device for a cathode closed cell stack or a methanol fuel cell according to claim 2, characterized in that the three-way flow theoretical optimization specifically comprises the steps of: Respectively defining a first parameter set and a second parameter set for describing geometric characteristics of the high-speed centrifugal impeller (2) and the volute (4), and establishing at least one association constraint relation between the first parameter set and the second parameter set; Based on a first parameter set, a second parameter set and an association constraint relation, constructing a parameterized three-dimensional geometric model of the high-speed centrifugal impeller (2) and the volute (4), taking parameters which are not fixed by the association constraint relation in the first parameter set and the second parameter set as adjustable parameters, taking average aerodynamic efficiency under a plurality of back pressure working conditions of 1kPa to 10kPa of the fuel cell and high-efficiency working area flow width under a specified back pressure as optimization targets, and carrying out iterative optimization on the parameterized three-dimensional geometric model by driving an automated computational fluid mechanics simulation flow to obtain a pareto optimal design scheme set; And selecting an optimal design scheme from the pareto optimal design scheme set, and verifying the flow stability and the output stability of the pareto optimal design scheme under the simulated back pressure transient working condition through unsteady CFD simulation.
  4. 4. The air supply device for a cathode closed cell stack or a methanol fuel cell according to claim 1, characterized in that the brushless dc motor (1) employs a hybrid ceramic ball bearing, wherein the bearing balls are of silicon nitride material and the bearing rings are made of steel and filled with high temperature resistant grease; The rotor assembly of the brushless direct current motor (1) is corrected through high-speed dynamic balance with the precision not lower than G2.5, and the balance rotating speed is not lower than 1.2 times of the maximum working rotating speed of the brushless direct current motor (1).
  5. 5. Air supply device for a cathode closed cell stack or a methanol fuel cell according to claim 4, characterized in that the duty cycle of the PWM signal is dynamically adjusted and the rotational speed of the brushless dc motor (1) is adjusted by the duty cycle of the PWM signal, in particular comprising: The electronic control unit samples load current of a pile or a fuel cell in real time, and instantly outputs a feedforward instruction of a first target rotating speed corresponding to the current load current by inquiring or interpolating a preset load current-target rotating speed mapping table; the electronic control unit receives the first actual rotating speed of the brushless direct current motor (1) at the same time, and calculates the deviation between the first target rotating speed and the first actual rotating speed through the proportional-integral controller; dynamically calculating a first real-time PWM duty ratio through a proportional-integral regulation algorithm based on the deviation of the first target rotating speed and the first actual rotating speed; A PWM signal with a first real-time PWM duty cycle is output to a brushless DC motor (1) to enable a first actual rotating speed to track a first target rotating speed.
  6. 6. The air supply device for a cathode closed cell stack or a methanol fuel cell according to claim 5, wherein the load current-target rotation speed map is established by: Establishing a first mapping relation between load current and theoretical air flow based on the electrochemical model of the fuel cell and a preset stoichiometric ratio; establishing a second mapping relation between the theoretical air flow and the target rotating speed of the motor based on a pneumatic performance curve of the air supply device; And integrating the first mapping relation and the second mapping relation to generate a load current-target rotating speed mapping table.
  7. 7. The air supply device for a cathode closed cell stack or a methanol fuel cell according to claim 5, wherein the electronic control unit further has an adaptive feed-forward compensation function: When the electric pile or the fuel cell is in a stable working condition, obtaining a second actual rotating speed of the brushless direct current motor (1), obtaining a second target rotating speed corresponding to the brushless direct current motor (1) under the current load current based on a load current-target rotating speed mapping table, and calculating the deviation between the second actual rotating speed and the second target rotating speed; When the deviation between the second actual rotating speed and the second target rotating speed exceeds a preset deviation threshold value, carrying out online fine adjustment on the second target rotating speed corresponding to the corresponding load current in the load current-target rotating speed mapping table at a preset learning rate; the formula for online trimming is as follows: ; Wherein, the A second target rotation speed before and after fine tuning respectively, In order for the rate of learning to be high, A continuous deviation of the second actual rotational speed from the second target rotational speed; The stable working condition is a state in which the fluctuation rate of the load current of the electric pile or the fuel cell is lower than a first threshold value, the actual rotation speed fluctuation rate of the brushless direct current motor is lower than a second threshold value, and the deviation of the actual rotation speed and the target rotation speed is continuously lower than a third threshold value.
  8. 8. The air supply device for a cathode closed cell stack or a methanol fuel cell according to claim 5, wherein the electronic control unit further has a rapid response function against load disturbance: calculating the change rate of the load current in real time; When the absolute value of the change rate exceeds a preset step judgment threshold value, immediately calculating a dynamic rotating speed feedforward compensation value according to the magnitude and the direction of the change rate; Superposing the dynamic rotating speed feedforward compensation value on the first target rotating speed to form a lifted first target rotating speed; dynamic rotation speed feedforward compensation value The calculation formula of (2) is as follows: ; ; Wherein, the For the dynamic feed-forward coefficient, For the rate of change of the load current, Max represents the maximum value for the selectable rate-of-change dead band threshold.
  9. 9. The air supply device for a cathode closed cell stack or a methanol fuel cell of claim 5, wherein the electronic control unit is further integrated with safety boundary protection logic: Calculating a limit rotating speed corresponding to a theoretical maximum air demand according to the current load current and a preset maximum allowable stoichiometric ratio; Comparing the limit rotation speed with the highest safe rotation speed of the brushless direct current motor (1); when the limit rotating speed reaches or exceeds the highest safe rotating speed, limiting the first target rotating speed to the highest safe rotating speed or a preset bottom-protecting rotating speed corresponding to the lowest safe air supply quantity, and triggering a system alarm; The bottom-protecting rotating speed is a motor target rotating speed corresponding to a minimum stoichiometric ratio required for preventing cathode hypoxia, which is preset in a pneumatic performance curve.
  10. 10. A method of using the air supply device for a cathode closed cell stack or a methanol fuel cell according to any one of claims 1 to 9, characterized by comprising the steps of: Acquiring load current of a galvanic pile or a fuel cell in real time, and determining target air flow according to the load current; determining a target rotating speed of the brushless direct current motor based on the target air flow and the current system back pressure; And regulating the real-time rotating speed of the brushless direct current motor to a target rotating speed through closed-loop control so as to output air matched with the load demand.

Description

Air supply device and method for cathode closed galvanic pile or methanol fuel cell Technical Field The invention relates to the technical field of hydrogen energy power, in particular to an air supply device and an air supply method for a Proton Exchange Membrane Fuel Cell (PEMFC), especially a cathode closed type galvanic pile or a Direct Methanol Fuel Cell (DMFC). Background Hydrogen fuel cells, particularly Proton Exchange Membrane Fuel Cells (PEMFC), have become the core in the field of hydrogen energy power technology due to their outstanding advantages of high energy density, fast start-up, low temperature operation, and environmental friendliness. Air (or oxygen) is used as an oxidant necessary for the cathode reaction, and the accuracy, stability and dynamic response speed of the supply directly determine the power generation efficiency, the output power density and the long-term operation durability of the electric pile. Therefore, the air supply system is an indispensable key auxiliary subsystem of the fuel cell power system, and the performance of the air supply system directly influences the technical index and the commercial feasibility of the whole power platform. The design of the traditional fuel cell air supply system is mainly oriented to application scenes such as automobiles, large-scale fixed power generation or standby power sources and the like. In these scenarios, the tolerance of the system to the volume, weight, power consumption and operating noise of the air supply is relatively high, with design emphasis on meeting flow and medium back pressure requirements at high power output. Common commercial schemes, such as positive displacement Roots fans or screw compressors, provide higher outlet pressures, but their operating principles result in complex structures, bulky volumes, significant weight, high mechanical noise, and considerable power consumption in auxiliary systems. Meanwhile, the dynamic response speed is low (usually in the second level) based on the adjustment mode of the motor rotation speed or the valve opening, and the application requirement of frequent and rapid fluctuation of the load is difficult to meet. With the rapid evolution of hydrogen energy power technology to the directions of miniaturization, light weight, high integration and high dynamic performance, emerging applications such as unmanned aerial vehicles, portable power supplies, light vehicles, auxiliary Power Units (APU), and miniature Cogeneration (CHP) systems have placed unprecedented demanding requirements on air supply systems. Under severe space and weight constraints, the application scenes generally require that the supply device has enough back pressure capacity to cope with high-altitude low-pressure or system internal resistance, millisecond-level dynamic response speed to match load fluctuation, low power consumption and low noise to realize efficient mute operation, high reliability and long service life to adapt to complex working conditions and long-term use. Particularly, the cathode closed type galvanic pile and the Direct Methanol Fuel Cell (DMFC) have higher system flow resistance, and further highlight the necessity of stable air supply under high back pressure. Currently, the traditional air supply scheme is difficult to cooperatively optimize in key indexes such as volume, efficiency, response speed, noise, service life and the like, and becomes a key bottleneck for restricting the large-scale application of the hydrogen energy power technology in the front-edge field. In these emerging applications, cathode-enclosed stack designs (aimed at improving reactant gas utilization and system compactness) and direct methanol fuel cell systems, because of their generally higher internal runner pressure losses, further pose a clear challenge to the backpressure capability of the air supply components. The supply device not only needs to provide flow under free air intake conditions, but also needs to stably and adjustably deliver sufficient air under a back pressure environment of 1 kPa to 10 kPa or higher. The flow rate of the traditional low-pressure fan is sharply attenuated under the back pressure, and the traditional high-pressure air compressor is difficult to be suitable for the problems of volume, weight, noise, power consumption and the like. Therefore, the core contradiction in the current technical field is that an advanced air supply solution which can integrate high back pressure capability, high pneumatic/motor efficiency, quick dynamic response, low running noise, long service life and intelligent control on the premise of small volume and light weight is urgently needed in the market. In the prior art, in the multi-objective and strong-constraint optimization space, an obvious short plate often exists, and the requirements of the high-performance miniaturized fuel cell system cannot be fully met. This has become a key bottleneck restricting the popularization of hydroge