Method and system for predicting possible fault of cooling fan

Abstract

A method of predicting a possible failure of a cooling fan includes driving a motor of the cooling fan according to a control rate; generating a first rate according to an average rate of the motor; generating a first current according to an average current of the motor; acquiring a system coefficient from a memory; generating a current threshold according to the first rate and the system coefficient; and triggering an alarm signal if the first current exceeds the current threshold by a threshold amount.

Description

Technical Field

[0001] The present invention relates to a feedback control, and more particularly to a system and method for predicting possible failure of a cooling fan. Background Art

[0002] Cooling fans are commonly used to cool electronic devices, thereby preventing them from overheating. In data centers, for example, fans play a critical role in ensuring that servers are not damaged by overheating. Such cooling fans can be found inside tower and rack servers to cool their internal components; they can be chassis mounted fans, used to cool blade servers and other electronic components housed within the chassis; they can be rack mounted fans, used to cool servers and other electronic components within the rack; and they can be large fans used for data center air conditioning and air handling. These cooling fans are essential to keeping computer systems operating optimally. If for some reason a cooling fan is unable to adequately dissipate excess heat, it can cause irreversible thermal damage to the electronic equipment.

[0003] Prior art patents (e.g., U.S. Pat. No. 6,400,113, U.S. Pat. No. 7,387,499, and U.S. Pat. No. 10,519,960) have disclosed techniques for monitoring, testing, and grouping fans with similar characteristics to identify cooling fans that are operating outside of a reference benchmark range (e.g., revolutions per minute (RPM)).

[0004] U.S. Patent No. 6,400,113, "APPARATUS AND METHOD FOR MONITORING FAN SPEEDS WITHIN A COMPUTING SYSTEM" describes a device for monitoring fan speed in a computer system, which has a tachometer that rotates with the fan and provides a speed signal with multiple pulses during each rotation of the fan. The speed signal is in the form of a square wave signal that is inverted between a high level and a low level as an input to a signal generator. The square wave signal is input to multiple input ports of a microprocessor. These input ports are sampled sequentially, and the sampling frequency provides at least two samples per cycle of the fastest square wave signal. The transitions of each square wave signal within a predetermined time interval are thereby detected and calculated. For each input port, the calculated number of transitions is compared with the stored acceptable value to determine whether the fan is operating within an acceptable speed range.

[0005] U.S. Patent No. 7,387,499, "SYSTEM AND METHOD FOR TESTING THE OPERATION OF A COOLING FAN" describes a method for testing the operation of a cooling device of an information processing system. The method includes determining a first rotational speed of a fan used to operate the cooling device, wherein the first rotational speed is less than a maximum rotational speed of the fan. The method includes sending a signal to the fan to rotate the fan at the first rotational speed, and detecting a current rotational speed of the fan. The method includes comparing the detected current rotational speed of the fan with the first speed of the fan, if the detected current rotational speed is substantially equal to or greater than the first speed of the fan, continuing the initialization process of the information processing system; if the detected current rotational speed of the fan is less than the first speed, further testing the fan.

[0006] U.S. Patent No. 10,519,960, "FAN FAILURE DETECTION AND REPORTING" relates to a fan failure detection and reporting system that organizes fans having similar characteristics into groups. The system establishes one or more reference characteristics for a given group of fans and identifies tolerance metrics for each reference characteristic. The system identifies a fan having a performance characteristic that exceeds a corresponding reference characteristic of the group to which the fan belongs as a problematic fan by monitoring and corresponding tolerance metrics of the reference characteristics, and generates a notification to at least identify the problematic fan. In an embodiment, the system can monitor the fans during operation of the fans to identify fan characteristics used to group and identify problematic fans. Thus, the system can detect problematic fans even if the system initially has limited or no knowledge of the fans.

[0007] Unfortunately, the above prior art is not sufficient to detect signs of impending fan failure when the fan is running at a specified speed. To solve this problem, the present invention introduces a method and apparatus for detecting signs of impending fan failure when the fan is about to fail. Summary of the invention

[0008] The embodiment provides a method for predicting a possible failure of a cooling fan. The method includes driving a motor of the cooling fan according to a control speed; generating a first speed according to an average speed of the motor; generating a first current according to an average current of the motor; obtaining a system coefficient from a memory; generating a current threshold according to the first speed and the system coefficient; and triggering an alarm signal if the first current exceeds the current threshold by a threshold amount.

[0009] Another embodiment provides a method for predicting a possible failure of a cooling fan. The method includes driving a motor of the cooling fan according to a control speed; generating a first speed according to an average speed of the motor; generating a first current according to an average current of the motor; obtaining a current threshold from a memory according to the first speed; and triggering an alarm signal if the first current exceeds the current threshold by a threshold amount.

[0010] Another embodiment provides a method for predicting a possible failure of a cooling fan. The method includes driving a motor of the cooling fan according to a controlled speed; generating a first speed according to an average speed of the motor; generating a first current according to an average current of the motor; generating a circuit voltage according to an input voltage of the motor; generating an input power according to the circuit voltage and the first current; retrieving a maximum input power from a memory according to the first speed; and triggering an alarm signal if the input power exceeds the maximum input power by a threshold amount.

[0011] Another embodiment provides a cooling fan control system, which includes an inverter, a motor coupled to the inverter, a Clarke conversion module coupled to the inverter, a Park conversion module coupled to the Clarke conversion module, a position and velocity estimator coupled to the Park conversion module, a low-pass filter coupled to the position and velocity estimator, a first subtractor coupled to the position and velocity estimator, a first proportional integral (PI) controller coupled to the first subtractor, a second subtractor coupled to the first PI controller and the Park conversion module, a second PI controller coupled to the second subtractor, and a space vector pulse width modulation (SVPWM) module coupled to the second PI controller, the position and velocity estimator and the inverter. The inverter is used to generate a first phase current, a second phase current and a third phase current according to an input voltage and a plurality of control signals. The motor is used to drive a cooling fan according to the first phase current, the second phase current and the third phase current. The Clarke conversion module is used to generate a first stator current and a second stator current through Clarke conversion according to the first phase current and the second phase current. The Park conversion module is used to generate a direct current and a quadrature current through Park conversion according to the rotor angle, the first stator current and the second stator current. The position and rate estimator is used to generate a rate signal and a rotor angle according to the direct current and the quadrature current. The low-pass filter is used to generate an average current of the motor according to the quadrature current. The first subtractor is used to generate a first difference signal according to the control rate and the rate signal. The first proportional-integral controller is used to generate a proportional-integral signal according to the first difference signal. The second subtractor is used to generate a second difference signal according to the proportional-integral signal and the quadrature current. The second proportional-integral controller is used to generate a duty cycle signal according to the second difference signal. The space vector pulse width modulation module is used to generate a plurality of control signals for the inverter according to the duty cycle signal and the rotor angle. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1A , Figure 1B and Figure 1C FIG. 4 is a schematic diagram of a cooling fan control system according to an embodiment of the present invention.

[0013] Figure 2 Tie Figure 1A-Figure 1C A flow chart of an embodiment of a method for predicting possible failure of a cooling fan implemented by a cooling fan control system.

[0014] Figure 3 Tie Figure 1A-Figure 1C A flow chart of another embodiment of a method for predicting possible failure of a cooling fan implemented by a cooling fan control system.

[0015] Figure 4 Tie Figure 1A-Figure 1C A flow chart of another embodiment of a method for predicting possible failure of a cooling fan implemented by a cooling fan control system.

[0016]

Explanation of symbols

[0017] 1: Cooling fan control system

[0018] 20: Inverter

[0019] 10: Motor

[0020] 100: Microcontroller

[0021] 110: Memory

[0022] 120, 130: Subtractor

[0023] 125, 145: Proportional Integral (PI) controller

[0024] 140: Clarke conversion module

[0025] 150: Parker conversion module 150

[0026] 155: Low pass filter

[0027] 160: Position and velocity estimator

[0028] 170: Space vector pulse width modulation module

[0029] ω c : Control rate

[0030] I A ,I B ,I C :Phase current

[0031] I α ,I β : Stator current

[0032] θ r :Rotor angle

[0033] I d :DC current

[0034] I q :Quadrature Current

[0035] ω r :Rate signal

[0036] I ω :PI signal

[0037] Du: Duty cycle signal

[0038] I avg :Average current

[0039] 102, 103: Resistance

[0040] V IN :Input voltage

[0041] Ve: Circuit voltage

[0042] S210-S270, S310-S370, S410-S470: Steps 200, 300, 400: Method DETAILED DESCRIPTION

[0043] For the purpose of describing the innovative aspects of the present invention, the following description is only directed to certain embodiments. However, those skilled in the art will appreciate that the present invention can be applied in many different ways.

[0044] Fans are often used to cool electronic equipment and thereby prevent it from overheating. For example, in a data center, fans play a key role in ensuring that servers do not overheat. Such fans may include, but are not limited to, fans installed within tower servers and rack servers and used to cool their internal components, chassis mounted fans used to cool blade servers and other electronic components housed within a chassis, rack mounted fans used to cool servers and other electronic components within a rack, and large fans used as air conditioning and air handling systems in data centers.

[0045] In many data centers, fans used to cool servers can be removed and replaced with other fans with different characteristics. For example, a chassis-mounted fan with a maximum speed of 6000 RPM (rotations per minute) can be removed and replaced with a fan with a maximum speed of 8000 RPM. This ability to replace fans enables data center managers to selectively install various types of fans (e.g., fans made by different manufacturers, different models of fans made by the same manufacturer, and fans with different characteristics) based on a variety of factors such as cost and performance. For example, one might choose to install high-efficiency fans regardless of cost, while another might choose to install fans that are sufficient to cool the servers at a reduced cost.

[0046] It is desirable to be able to monitor the performance of one or more installed fans to detect fan failures and identify fans that are operating abnormally, suboptimally, sub-optimally, or at risk of failure, especially when the fans themselves do not have built-in diagnostic control units. In such environments, a variety of different types of fans may be installed in a server, chassis, rack, or data center, and the monitoring device may not know the expected characteristics of the installed fan or fan group. In such cases, it is difficult to confirm whether the fan is operating as expected because there is no data on the expected characteristics to compare with the monitored fan performance.

[0047] This article describes a cooling fan control system and a method for predicting possible failure of a cooling fan, which solves the problems of the above-mentioned traditional fan cooling system. The system can be used to organize fans with similar characteristics into groups, further establish one or more reference characteristics (e.g., input power and average current of the electric motor) of at least one cooling fan, and determine the tolerance or threshold measurement standard of each reference characteristic. The system can also identify problematic fans that exceed the tolerance or threshold of the corresponding reference characteristics when operating, and generate an alarm signal to identify the problematic fans.

[0048] Figure 1A , Figure 1B and Figure 1C FIG. 1 is a schematic diagram of a cooling fan control system 1 according to an embodiment of the present invention. The cooling fan control system 1 comprises a microcontroller (MCU) 100 and a memory 110 (eg, Figure 1B The two work together to provide a control signal to the inverter 20. The control algorithm used here is field-oriented control (FOC). The microcontroller 100 can generate a control rate ω for controlling the motor 10. c (in the form of a signal).

[0049] The inverter 20 supplies power to the motor 10 to drive the cooling fan. The inverter 20 generates a phase current I A ,I B ,I C Phase current I A and I B The Clarke transformation module 140 samples the coordinates for the transformation (i.e., by Clarke transformation). This transformation transforms the three-axis (two-dimensional coordinate system) into a two-axis system, generating the stator current I α and I β .

[0050] If the phase current I A +I B +I C =0, then:

[0051] Stator current I α It can be expressed as: α =I A

[0052] Stator current I β It can be expressed as:

[0053] Stator current I α and I β These currents are further converted by the Park transformation module 150 into another two-axis system that rotates with the rotor flux.

[0054] The Park conversion module 150 converts the stator current I α and I β and the rotor angle θ r Generates DC current I d and the quadrature current I q Current I d and I q It can be expressed by a two-axis orthogonal rotation coordinate system called the dq axis. Therefore, the current I d and I q It can be generated by the following equation:

[0055] I d =I α ×cos(θr)+I β ×cos(θr)

[0056] I q =-I α ×sin(θr)+I β ×sin(θr)

[0057] In the above equation, the field flux component of the current is related to the DC current Id The torque component is consistent with the orthogonal current I q The rotor angle may be provided by the position and velocity estimator 160 .

[0058] Current I d and I q After being sent to the position and velocity estimator 160, the position and velocity estimator 160 may generate a velocity signal ω r (which includes the first speed) and the corresponding rotor angle θ r The first rate describes the angular rate of the motor 10 .

[0059] The subtractor 120 subtracts the first rate from the control rate ω c The first difference is subtracted to generate a first difference, and the first difference is input to a proportional integral (PI) controller 125, and then the PI controller 125 generates a PI signal I accordingly. ω Another subtractor 130 converts the PI signal I ω and quadrature current Iq Subtracting, the PI controller 145 obtains the output of the subtractor 130 to generate a duty cycle signal Du. Subsequently, the space vector pulse width modulation (SVPWM) module 170 can generate a duty cycle signal Du and the rotor angle θ according to the duty cycle signal Du. r A control signal for controlling the inverter 20 is generated.

[0060] Thus, the motor 10 may be operated within a feedback loop control and based on the control rate ω c The average speed of the motor 10 is adjusted. In addition, the low-pass filter (LPF) 155 can use the quadrature current I q To generate the average current I of the motor 10 avg .

[0061] In some embodiments, the average current I of the motor 10 can be generated based on the input current of the inverter 20. avg Methods. Figure 1C As shown, two resistors 102 and 103 form a voltage divider for IN Generates circuit voltage Ve. Input voltage V IN (also related to input power) can be applied to the motor 10 via the inverter 20. The circuit voltage Ve can be used to power the microcontroller 100 and / or the memory 110, both of which require less voltage than the motor 10. The memory 110 can be used to store system coefficients, such as various system voltages, currents and thresholds.

[0062] The above value or signal (for example, θ r ,I d ,I q ,I avg 、V IN ,ω r The signals may be in the form of voltage, current, analog signal and / or digital signal. These signals may be set to have appropriate values, and those skilled in the art may easily observe these signals and make corresponding adjustments.

[0063] The circuit configuration of the cooling fan control system 1 can be summarized as follows. The cooling fan control system 1 includes an inverter 20, a motor 10 coupled to the inverter 20, a Clarke conversion module 140 coupled to the inverter 20, a Park conversion module 150 coupled to the Clarke conversion module 140, a position and speed estimator 160 coupled to the Park conversion module 150, a low pass filter 155 coupled to the position and speed estimator 160, a subtractor 120 coupled to the position and speed estimator 160, a PI controller 125 coupled to the subtractor 120, a subtractor 130 coupled to the PI controller 125 and the Park conversion module 150, and an SVPWM module 170 coupled to the PI controller 145, the position and speed estimator 160, and the inverter 20.

[0064] The inverter 20 receives the input voltage V IN Power supply for input voltage V IN and control signal to generate phase current I A ,I B and I C The motor 10 is used to adjust the phase current I A ,I B and I C To drive the cooling fan. The Clark conversion module 140 is used to convert the phase current I A and I B The stator current I is generated by Clarke transformation α and I β The Park conversion module 150 is used to convert the rotor angle θ r , stator current I α and I β Generate DC current I through Park conversion d and the quadrature current I q The position and speed estimator 160 is used to calculate the position and speed of the DC current I d With the orthogonal current I q Generate rate signal ω r With the rotor angle θ r The low-pass filter 155 is used to filter the quadrature current I q The average current I generated by the motor 10 avgThe subtractor 120 is used to control the rate ω c With the rate signal ω r The PI controller 125 is used to generate a PI signal I according to the first difference signal. ω The subtractor 130 is used to calculate the PI signal I ω and the quadrature current I q The PI controller 145 is used to generate a duty cycle signal Du according to the second difference signal. The SVPWM module 170 is used to generate a duty cycle signal Du according to the duty cycle signal Du and the rotor angle θ r A control signal for the inverter 20 is generated.

[0065] The cooling fan control system 1 may further include a microcontroller 100 and a memory 110 coupled to the microcontroller 100. The microcontroller 100 may be used to generate a control rate ω c The memory 110 may be used to store system coefficients, current thresholds and / or maximum powers.

[0066] The cooling fan control system 1 may further include a first resistor 102 and a second resistor 103 connected in series to form a voltage divider for IN A circuit voltage Ve is generated.

[0067] Figure 2 1 is a flow chart of a method 200 for predicting a possible failure of a cooling fan implemented by the cooling fan control system 1. In this embodiment, the first current may be the orthogonal current I described in the cooling fan control system 1. q However, in some other embodiments, the first current may be a different current depending on the implementation.

[0068] The method 200 comprises the following steps:

[0069] Step S210 is based on the control rate ω c driving the motor 10 and measuring an average speed of the motor 10;

[0070] Step S220 generates a first speed according to the average speed of the motor 10;

[0071] Step S230 is based on the average current I of the motor 10. avg generating a first current;

[0072] Step S235: adjusting the first current according to the circuit voltage Ve;

[0073] Step S240 retrieves system coefficients from memory 110;

[0074] Step S250 generates a current threshold according to the first rate and the system coefficient;

[0075] Step S260: Whether the first current exceeds the current threshold by a threshold amount, or whether the first rate drops below the control rate ω c Reach a rate threshold; if so, proceed to step S270; if not, return to step S220;

[0076] Step S270 triggers an alarm signal when the cooling fan may fail.

[0077] Starting from step S210, the microcontroller 100 can control the speed according to the control rate ω c The motor 10 of the cooling fan is controlled by the inverter 20. In step S220, a first speed may be generated based on an average speed of the motor. In step S230, the average current I avg To generate the first current. Further details of the first current may be performed in step S235, which is related to the circuit voltage Ve and optionally one or more system voltages. The system voltage is the voltage used when establishing the current threshold during the system setting phase.

[0078] In step S240, a system coefficient related to motor characteristics, fan design and airflow resistance is retrieved from memory 110 through a lookup table corresponding to the first rate. Step S250 is to generate a current threshold according to the first rate and the system coefficient. The current threshold is a threshold calculated by multiplying the system coefficient by the first rate.

[0079] In steps S260 and S270, the alarm signal of possible cooling fan failure may be triggered in two cases: (1) the first current exceeds the current threshold by a threshold amount; or (2) the first rate drops below the control rate ω c Reach a rate threshold amount.

[0080] As used herein, the average speed of the motor refers to the speed at which the motor is controlled at a stable speed ω c The average motor speed during a period of operation. "Average Motor Current" refers to the average motor current during the same period of time as the "Average Motor Speed" is calculated.

[0081] Figure 3 1 is a flow chart of a method 300 implemented by the cooling fan control system 1 for predicting possible failure of a cooling fan. The method 300 comprises the following steps:

[0082] Step S310 is based on the control rate ω c driving the motor 10 and measuring an average speed of the motor 10;

[0083] Step S320 generates a first speed according to the average speed of the motor 10;

[0084] Step S330 is based on the average current I of the motor 10.avg generating a first current;

[0085] Step S340: adjusting the first current according to the circuit voltage Ve;

[0086] Step S350 retrieves the current threshold I from the memory 110 according to the first rate TH ;

[0087] Step S360: Whether the first current exceeds the current threshold I TH reaches a threshold amount, or whether the first rate drops below the control rate ω c Reach a rate threshold; if so, proceed to step S370; if not, return to step S320;

[0088] Step S370 triggers an alarm signal when the cooling fan may fail.

[0089] Starting from step S310, the microcontroller 100 can control the speed according to the control rate ω c The motor 10 of the cooling fan is controlled by the inverter 20. In step S320, a first speed may be generated based on an average speed of the motor 10. In step S330, a first speed may be generated based on an average current I of the motor 10. avg A first current is generated. Further details of the first current may be performed in step S340, which is related to the circuit voltage Ve and optionally one or more system voltages. The system voltage is the voltage at which the current threshold I is established during the system setting phase. TH The voltage used when

[0090] In step S350, a current threshold I associated with the motor speed value, motor characteristics, fan design, and airflow resistance is retrieved from the memory 110 through a lookup table corresponding to the first speed. TH . Current threshold I TH It is a value obtained based on the characteristics of the motor 10 and is stored in the memory 110 in advance.

[0091] In steps S360 and S370, the alarm signal indicating a possible cooling fan failure may be triggered in two situations: (1) the first current exceeds the current threshold I TH Reach a threshold amount; or (2) the first rate drops below the control rate ω c Reach a rate threshold amount.

[0092] As used herein, the average speed of the motor refers to the speed at which the motor is controlled at a stable speed ω c The average motor speed during a period of operation. "Average Motor Current" refers to the average motor current during the same period of time as the "Average Motor Speed" is calculated.

[0093] Figure 44 is a flow chart of a method 400 implemented by the cooling fan control system 1 for predicting possible failure of a cooling fan. The method 400 comprises the following steps:

[0094] Step S410 is based on the control rate ω c driving the motor 10 and measuring an average speed of the motor 10;

[0095] Step S420 generates a first speed according to the average speed of the motor 10;

[0096] Step S430 is based on the average current I of the motor 10. avg generating a first current;

[0097] Step S435 is based on the input voltage V IN Sampling the circuit voltage Ve;

[0098] Step S440 generates input power according to the first current and the circuit voltage Ve;

[0099] Step S450 retrieves the maximum input power from the memory 110;

[0100] Step S460: Whether the input power exceeds the maximum input power by a power threshold, or the first rate drops below the control rate ω c Reach a rate threshold; if so, proceed to S470; if not, return to S420;

[0101] Step S470 triggers an alarm signal when the cooling fan may fail.

[0102] Starting from step S410, the microcontroller 100 can control the speed according to the control rate ω c The motor 10 of the cooling fan is controlled by the inverter 20. In step S420, a first speed may be generated based on an average speed of the motor 10. In step S430, a first speed may be generated based on an average current I avg In step 435, the microcontroller 100 generates a first current. IN The circuit voltage Ve sampled by the microprocessor 110 can be used to calculate the input power, and the input power can be compared with the reference power to predict the possibility of cooling fan failure. In step S440, the input power is generated according to the first current and the circuit voltage Ve.

[0103] In step S450, the maximum input power related to the motor characteristics, fan design and airflow resistance is retrieved from the memory 110 through a lookup table corresponding to the first speed. The maximum input power is a value obtained according to the characteristics of the motor 10 and is pre-stored in the memory 110.

[0104] In steps S460 and S470, the alarm signal of potential failure of the cooling fan may be triggered in two cases: (1) the input power exceeds the maximum input power by a power threshold amount; or (2) the first rate drops below the control rate ω c Reach a rate threshold amount.

[0105] As used herein, the average speed of the motor refers to the speed at which the motor is controlled at a stable speed ω c The average motor speed during the period of operation. "Average Motor Current" refers to the average motor current during the same period of time as the "Average Motor Speed" is calculated.

[0106] The various embodiments described above disclose a system and method for predicting a possible failure of a cooling fan, so that a possible failure can be quickly discovered and resolved in a timely manner.

[0107] The terms "coupled", "connected", "electrically connected", etc. are used interchangeably herein and generally refer to a condition of being electrically connected (by wire or wireless means). Similarly, a first entity is considered to be "in communication" or "connected" with a second entity (or entities) when the first entity electrically sends and / or receives (by wire or wireless means) information signals to / from the second entity, regardless of the type of these signals (analog or digital). It should be understood that the various drawings (including component drawings) shown and discussed herein are for illustrative purposes only and are not drawn to scale.

[0108] It should also be understood that when the terms “include” and / or “comprises” are used in this specification, they specify the presence of stated features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0109] The various illustrative elements, logic, logic blocks, modules, circuits, operations, and algorithmic processes described in conjunction with the implementations disclosed herein may be implemented as electronic hardware, firmware, software, or a combination of hardware, firmware, or software, including the structures disclosed in this specification and their structural equivalents. In terms of functionality, the interchangeability of hardware, firmware, and software has been generally described and represented in the various illustrative components, modules, circuits, and processes described above. Whether such functionality is implemented in hardware, firmware, or software depends on the specific application and the design constraints imposed on the overall system.

[0110] The hardware and data processing apparatus for implementing the various illustrative elements, logic, logic blocks, modules and circuits described in conjunction with the aspects disclosed herein may be a general purpose single-chip processor or a multi-chip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic element (PLD), discrete gate or transistor logic, discrete hardware elements or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, or any conventional processor, controller, microcontroller or state machine. A processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration. In some embodiments, specific processes, operations and methods may be performed by circuits of specific functions.

[0111] As described above, in some aspects, the implementation of the subject matter described in this specification can be implemented as software. For example, the various functions of the components disclosed herein or the various blocks or steps of the methods, operations, processes or algorithms disclosed herein can be implemented as one or more modules of one or more computer programs. Such a computer program may include non-temporary processor-executable or computer-executable instructions encoded on one or more tangible processor-readable or computer-readable storage media, which are executed or controlled by a data processing device including components of the devices described herein. As an example and not a limitation, such a storage medium may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage device, or any other medium that can be used to store program code in the form of instructions or data structures. The combination of the above devices should also be included in the scope of the storage medium.

[0112] Various modifications of the embodiments described in the present invention will be apparent to those of ordinary skill in the art, and the general principles defined herein may be applied to other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the claims are not intended to be limited to the embodiments shown herein, but should be consistent with the broadest scope consistent with the present disclosure, the principles and novel features disclosed herein.

[0113] In addition, various features described in this specification as being implemented separately may also be implemented in a single implementation in combination. Conversely, various features described in this specification as being implemented in a single implementation may also be implemented in multiple implementations separately or in any suitable sub-combination. Thus, although a feature may be described above as functioning in a particular combination, or even initially claimed as such. In some cases, one or more features in a claimed combination may be deleted from the claimed combination, and the claimed combination may be a sub-combination or a variation of a sub-combination.

[0114] Similarly, although the operations are depicted in a particular order in the accompanying drawings, this should not be understood as necessarily performing such operations in the particular order shown or in a continuous order, or performing all the operations shown to achieve the desired result. In addition, the accompanying drawings may schematically depict another example process in the form of a flow chart. However, other operations not depicted may be incorporated into the illustrated example process. For example, one or more additional operations may be performed before, after, simultaneously, or between any of the illustrated operations. In some cases, multiplexing and parallel processing may be advantageous. In addition, the separation of the various system components described should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated into a single software product, or packaged into multiple software products. In addition, other embodiments are also within the scope of the appended claims. In some cases, the actions recorded in the claims may be performed in different orders and still achieve the desired results.

[0115] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the claims of the present invention should fall within the scope of the present invention.

Claims

1. A method for predicting a possible failure of a cooling fan, comprising: a motor driving a cooling fan according to a controlled rate; Generating a first speed according to an average speed of the motor; Generate a first current according to an average current of the motor; Obtaining a system coefficient from a memory; generating a current threshold according to the first rate and the system coefficient; and If the first current exceeds the current threshold by a threshold amount, an alarm signal is triggered.

2. The method according to claim 1, further comprising: generating a circuit voltage of a microcontroller according to an input voltage of the motor; and The first current is adjusted according to the circuit voltage of the microcontroller.

3. The method of claim 2, wherein: The motor is driven by the microcontroller using a field oriented control (FOC) algorithm.

4. The method of claim 1, further comprising triggering the alarm signal if the first rate drops below the control rate by a rate threshold amount.

5. The method of claim 1, wherein the system coefficient is obtained by searching a lookup table in the memory according to the first rate. The method of claim 1 , wherein the current threshold is equal to the system coefficient multiplied by the first rate.

7. The method of claim 1, wherein the system coefficient is related to a plurality of motor characteristics, a fan design, and an air flow resistance.

8. The method of claim 1, wherein the average speed of the motor is an average motor speed over a period of time in which the motor continues to run at the control speed, and the average current of the motor is an average motor current over the period of time.

9. A method for predicting a possible failure of a cooling fan, comprising: a motor driving a cooling fan according to a controlled rate; Generating a first speed according to an average speed of the motor; Generate a first current according to an average current of the motor; Obtaining a current threshold from a memory according to the first rate; and If the first current exceeds the current threshold by a threshold amount, an alarm signal is triggered.

10. The method of claim 9, further comprising: generating a circuit voltage of a microcontroller according to an input voltage of the motor; and The first current is adjusted according to the circuit voltage of the microcontroller.

11. The method of claim 10, wherein: The motor is driven by the microcontroller using a field oriented control (FOC) algorithm.

12. The method of claim 9, further comprising triggering the alarm signal if the first rate drops below the control rate by a rate threshold amount.

13. The method of claim 9, wherein the current threshold is obtained by searching a lookup table in the memory according to the first rate.

14. The method of claim 9, wherein the system coefficient is related to motor characteristics, a fan design, and an air flow resistance.

15. The method of claim 9, wherein the average speed of the motor is an average motor speed over a period of time in which the motor continues to run at the control speed, and the average current of the motor is an average motor current over the period of time.

16. A method for predicting a possible failure of a cooling fan, comprising: a motor driving a cooling fan according to a controlled rate; Generating a first speed according to an average speed of the motor; Generate a first current according to an average current of the motor; generating a circuit voltage according to an input voltage of the motor; generating an input power according to the circuit voltage and the first current; fetching a maximum input power from a memory according to the first rate; and If the input power exceeds the maximum input power by a threshold amount, an alarm signal is triggered.

17. The method of claim 16, further comprising triggering the alarm signal if the first rate drops below the control rate by a rate threshold amount.

18. The method of claim 16, wherein the maximum input power is obtained by searching a lookup table in the memory according to the first rate.

19. The method of claim 16, wherein: The motor is driven by the microcontroller using a field oriented control (FOC) algorithm.

20. A cooling fan control system, comprising: an inverter for generating a first phase current, a second phase current and a third phase current according to an input voltage and a plurality of control signals; a motor, coupled to the inverter, for driving a cooling fan according to the first phase current, the second phase current and the third phase current; a Clark conversion module, coupled to the inverter, for generating a first stator current and a second stator current through Clark conversion according to the first phase current and the second phase current; a Park conversion module, coupled to the Clark conversion module, for generating a DC current and a quadrature current through Park conversion according to a rotor angle, the first stator current and the second stator current; a position and velocity estimator, coupled to the Park conversion module, for generating a velocity signal and the rotor angle according to the DC current and the quadrature current; a low pass filter, coupled to the position and velocity estimator, for generating an average current of the motor according to the quadrature current; a first subtractor, coupled to the position and velocity estimator, for generating a first difference signal according to a control velocity and the velocity signal; a first proportional integral (PI) controller, coupled to the first subtractor, for generating a proportional integral signal according to the first difference signal; a second subtractor, coupled to the first proportional-integral controller and the Park conversion module, for generating a second difference signal according to the proportional-integral signal and the quadrature current; a second proportional-integral controller, coupled to the second subtractor, for generating a duty cycle signal according to the second difference signal; and A space vector pulse width modulation (SVPWM) module is coupled to the second proportional integral controller, the position and speed estimator and the inverter, and is used to generate the multiple control signals for the inverter according to the duty cycle signal and the rotor angle.

21. The system of claim 20, further comprising: a microcontroller for generating the control rate; and A memory is coupled to the microcontroller and is used to store a plurality of system coefficients, a current threshold and / or a maximum power.

22. The system of claim 20, further comprising: A first resistor and a second resistor are connected in series to form a voltage divider, wherein the voltage divider generates a circuit voltage according to the input voltage.

Images