Electronic system with heat dissipation and feedforward active noise control function

Abstract

The electronic system includes a fan module, an embedded controller, a reference microphone, a speaker module and an active noise reduction controller. The speaker module provides an anti-phase noise signal to cancel the noise generated by the electronic system in operation according to a speaker control signal. The reference microphone detects the broadband noise generated by the fan module in operation to provide a corresponding broadband noise signal. A virtual microphone module of the active noise reduction controller provides a virtual error signal according to a first transfer function between the reference microphone and a physical microphone at a predetermined fan speed, a second transfer function between the speaker module and the physical microphone when there is no wind pressure and the broadband noise signal, and generates the speaker control signal according to a synchronization signal, the broadband noise signal and the virtual error signal.

Description

Technical Field

[0001] This invention provides an electronic system with heat dissipation and feedforward active noise control functions, and particularly relates to an electronic system with heat dissipation and virtual microphone signals to realize feedforward active noise control functions. Background Technology

[0002] In today's information society, computer systems have become an indispensable information tool for most people. To prevent components from overheating and causing power reduction or damage, computer systems generally use fans to provide cooling, either to expel heat generated inside the device or to draw in cool air from outside.

[0003] The fan's speed and static pressure determine its airflow. The noise level of a fan is roughly proportional to the fifth root of its speed; the faster the speed, the stronger the heat dissipation, but the louder the noise. As central processing units become more powerful, the waste heat generated inside the device also increases. In addition, the trend of miniaturization reduces heat flow efficiency. How to balance heat dissipation and noise reduction is an important issue. Summary of the Invention

[0004] This invention provides an electronic system with heat dissipation and feedforward active noise control functions, comprising a fan module, an embedded controller, a reference microphone, a speaker module, and an active noise cancellation controller. The fan module operates according to a fan control signal to provide heat dissipation. The embedded controller provides the fan control signal. The reference microphone detects broadband noise generated by the fan module during operation to provide a corresponding broadband noise signal. The speaker module provides an inverse noise signal according to the speaker control signal. The active noise cancellation controller provides a virtual error signal based on a first transfer function, a second transfer function, and the broadband noise signal, and generates a speaker control signal based on a synchronization signal, the broadband noise signal, and the virtual error signal. The synchronization signal includes information about the structure and operating settings of the fan module; the first transfer function is a transfer function between the reference microphone and the physical microphone when the speaker module is not operating; the second transfer function is a transfer function between the speaker module and the physical microphone when the fan module is not operating; and the inverse noise signal includes multiple noise cancellation waveforms to cancel out the noise generated by the electronic system during operation. Attached Figure Description

[0005] Figure 1 This is a functional block diagram of an electronic system with heat dissipation and feedforward active noise control functions operating in offline mode, according to an embodiment of the present invention.

[0006] Figure 2This is a functional block diagram of an electronic system with heat dissipation and feedforward active noise control functions operating in online mode, according to an embodiment of the present invention.

[0007] Figure 3 This is a schematic diagram illustrating the implementation of an active noise reduction controller in an electronic system with heat dissipation and feedforward active noise control functions, according to an embodiment of the present invention.

[0008] Figure 4 The flowchart shows an electronic system with heat dissipation and feedforward active noise control functions operating in offline mode according to an embodiment of the present invention.

[0009] Figure 5 This diagram illustrates the transfer function between the speaker module, reference microphone, and physical microphone during signal transmission in an electronic system with heat dissipation and feedforward active noise control functions in an embodiment of the present invention, when the system is running in offline mode.

[0010] Figure 6 This is a flowchart illustrating the operation of an electronic system with heat dissipation and feedforward active noise control functions in online mode, as described in an embodiment of the present invention.

[0011] Explanation of reference numerals in the attached figures:

[0012] 10: Processor

[0013] 20: Fan Module

[0014] 30: Embedded Controller

[0015] 40: Speaker Module

[0016] 50: Reference microphone

[0017] 60: Active noise cancellation controller

[0018] 62: Frequency Calculator

[0019] 64: Signal Generator

[0020] 66: Digital Filter

[0021] 68: Speaker module driver circuit

[0022] 70: Virtual microphone module

[0023] 71: First Path Compensation Transfer Function Module

[0024] 72: Second Path Compensation Transfer Function Module

[0025] 76: Adaptive Filter

[0026] 80: Physical microphone

[0027] 100: Electronic Systems

[0028] 410-430, 610-650: Steps

[0029] S FG Fan control signal

[0030] S MIC Speaker control signal

[0031] S SYN Synchronization signal

[0032] y(n): Inverting noise signal

[0033] y'(n): Processed inverted noise signal

[0034] e(n): Error signal

[0035] e'(n): Virtual error signal

[0036] f(n): Wideband noise signal

[0037] d(n): Noise signal

[0038] x(n): Reference signal

[0039] x'(n): Processed reference signal

[0040] P(Z), P'(Z): Transfer functions between the reference microphone and the physical microphone

[0041] D(Z), D'(Z): Transfer functions between the speaker module and the reference microphone

[0042] C(Z), C'(Z): Transfer functions between the speaker module and the physical microphone

[0043] W(Z): Parameters of the digital filter Detailed Implementation

[0044] Figure 1 This is a functional block diagram of an electronic system 100 with heat dissipation and feedforward active noise control functions operating in offline mode according to an embodiment of the present invention. Figure 2 This is a functional block diagram of an electronic system 100 with heat dissipation and feedforward active noise control functions operating in online mode according to an embodiment of the present invention.

[0045] The electronic system 100 includes a processor 10, a fan module 20, an embedded controller (EC) 30, a speaker module 40, a reference microphone 50, and an active noise cancellation (ANC) controller 60, wherein the active noise cancellation controller 60 includes a virtual microphone module 70.

[0046] In this invention, the electronic system 100 can operate in both an offline mode and an online mode. For example... Figure 1 As shown, when the electronic system 100 is running in offline mode, the active noise cancellation controller 60 will operate based on the error signal e(n) provided by a physical microphone 80 to determine the transfer functions D'(Z) between the speaker module 40 and the reference microphone 50, the transfer function C'(Z) between the speaker module 40 and the error microphone 55, and the transfer function P'(Z) between the reference microphone 50 and the physical microphone 80 at a specific fan speed. Figure 2 As shown, when the electronic system 100 is running in online mode, the active noise cancellation controller 60 operates based on the virtual error signal e'(n) provided by the virtual microphone module 70 to provide the speaker control signal S. MIC This enables feedforward active noise control. The following sections of the manual will detail the operation of the electronic system 100 in both offline and online modes.

[0047] The processor 10 may be a central processing unit (CPU) or a graphics processing unit (GPU). It is the key computing engine in the electronic system 100, responsible for executing the instructions and programs required by the operating system, and is also the main source of waste heat in the electronic system 100.

[0048] The fan module 20 may have different structures depending on its type, but it mainly uses a motor to drive the fan blades to rotate, drawing cooler air into the chassis and expelling hotter air from inside, thereby achieving a heat dissipation effect. In this invention, the fan module 20 will operate according to a fan control signal S provided by the embedded controller 30. FG To run, fan control signal S FG The higher the value, the faster the motor speed in fan module 20, resulting in stronger heat dissipation, but also generating more noise. During the operation of electronic system 100, fan module 20 is typically the primary source of noise. In one embodiment, the fan control signal S... FGThe signal can be a square wave signal with pulse width modulation (PWM), which adjusts the motor speed in fan module 20 by changing its duty cycle. In one embodiment, fan module 20 may include one or more axial or centrifugal fans. However, the number of fans, fan type, and fan drive method included in fan module 20 do not limit the scope of the invention.

[0049] The embedded controller 30 stores the EC codes for various operations of the relevant electronic system 100 and the timing of important power-on signals. In the power-off state, the embedded controller 30 remains operational, awaiting user power-on notifications; in the power-on state, the embedded controller 30 controls the system's standby / sleep state, keyboard controller, charging indicator light, and motor speed in the fan module 20. The embedded controller 30 typically includes a temperature sensor (not shown). Figure 1 and Figure 2 This monitors the operating temperature of the processor 10 and outputs a fan control signal S accordingly. FG As the operating temperature of processor 10 increases, the fan control signal S... FG The longer the working cycle, the faster the motor speed in fan module 20; the lower the operating temperature of processor 10, the faster the fan control signal S... FG The shorter the working cycle, the slower the motor speed in fan module 20.

[0050] The loudspeaker module 40 is an electronic component that converts electronic signals into sound signals. It typically includes a diaphragm and a driving circuit consisting of an electromagnet and a voice coil. The loudspeaker module 40 can operate according to the loudspeaker control signal S provided by the active noise cancellation controller 60. MIC To run, when the speaker control signal S MIC When current passes through the voice coil, the voice coil vibrates with the frequency of the current, and the diaphragm connected to the voice coil also vibrates, thereby pushing the surrounding air to vibrate and produce sound. In this embodiment of the invention, the diaphragm of the speaker module 40 is disposed within the air outlet structure of the fan module 20, and can be controlled according to the speaker control signal S. MIC This generates an inverted noise signal y(n).

[0051] A reference microphone 50 is positioned close to the fan blades in the fan module 20 to acquire the noise generated during the operation of the fan module 20 and transmits a measured wideband noise signal f(n) to the active noise cancellation controller 60. The wideband noise signal f(n) contains the wideband noise spectrum of the airflow noise generated by the fan module 20 during operation. In one embodiment, the reference microphone 50 may be a digital microelectromechanical system (MEMS) microphone, possessing high heat resistance, high vibration resistance, and high resistance to radio frequency interference. However, the type of reference microphone 50 does not limit the scope of this invention.

[0052] Figure 3 This is a schematic diagram illustrating the implementation of the active noise cancellation controller 60 in an embodiment of the present invention. The active noise cancellation controller 60 includes a frequency calculator 62, a signal generator 64, a digital filter 66, a speaker module driver circuit 68, a first path compensation transfer function module 71, a second path compensation transfer function module 72, an adaptive filter 76, and a virtual microphone module 70.

[0053] When the electronic system 100 is running in offline mode, the active noise cancellation controller 60 can receive a synchronization signal S. SYN The system receives a broadband noise signal f(n) from the reference microphone 50, corresponding to the anti-phase noise signal y(n), and an error signal e(n) from the physical microphone 80. Based on these, it calculates the transfer functions C'(Z) between the speaker module 40 and the physical microphone 70, D'(Z) between the speaker module 40 and the reference microphone 50, and P'(Z) between the reference microphone 50 and the physical microphone 80. The synchronization signal S... SYN This includes information about the structure of the relevant fan module 20 (e.g., the number of fan blades) and its operating settings (e.g., motor speed in different modes). Figure 1 and Figure 2 In the embodiment shown, the synchronization signal S SYN This can be provided by the embedded controller 30. In other embodiments of the invention, the synchronization signal S SYN It can be provided by processor 10 or other components.

[0054] When the electronic system 100 is running in online mode, the active noise cancellation controller 60 can receive a synchronization signal S. SYN The virtual microphone 70 receives a broadband noise signal f(n) from the reference microphone 50, along with the corresponding anti-phase noise signal y(n). The virtual microphone 70 provides a virtual error signal e'(n) based on the transfer functions C'(Z) and P'(Z) derived in offline mode. This is based on the synchronization signal S. SYNThe active noise cancellation controller 60 can calculate the broadband noise generated by the fan module 20 when it runs at a predetermined fan speed, based on the broadband noise signal f(n), the virtual error signal e'(n), and the transfer functions C'(Z) and D'(Z) obtained in offline mode, and then provide the speaker control signal S accordingly. MIC This drives the speaker module 40 so that the inverted noise signal y(n) provided by the speaker module 40 can effectively cancel out the influence of the noise signal d(n), that is, to reduce the virtual error signal e'(n) to 0 as much as possible. Figure 1 and Figure 2 In the embodiment shown, the synchronization signal S SYN This can be provided by the embedded controller 30. In other embodiments of the invention, the synchronization signal S SYN It can be provided by processor 10 or other components.

[0055] Figure 4 The flowchart shown illustrates an electronic system 100 with heat dissipation and feedforward active noise control functions operating in offline mode according to an embodiment of the present invention, which includes the following steps:

[0056] Step 410: Install a physical microphone 80 at the air outlet of the electronic system 100.

[0057] Step 420: With the speaker module 40 not running, measure the transfer function P'(Z) between the reference microphone 50 and the physical microphone 70.

[0058] Step 430: With the fan module 20 not running, measure the transfer function D'(Z) between the speaker module 40 and the reference microphone 50, and the transfer function C'(Z) between the speaker module 40 and the physical microphone 80.

[0059] Figure 5 This diagram illustrates the transfer function of an electronic system 100 with heat dissipation and feedforward active noise control functions in an embodiment of the present invention during signal transmission between a speaker module 40, a reference microphone 50, and a physical microphone 80 when the system is operating in offline mode. Figure 5 In this context, d(n) represents the noise signal to be eliminated during offline operation of the electronic system 100, f(n) represents the broadband noise signal measured by the reference microphone 50, e(n) represents the error signal output by the physical microphone 80, y(n) represents the inverted noise signal provided by the speaker module 40, and S... MICThe speaker control signal output by the active noise cancellation controller 60 represents the signal. P(Z) represents the transfer function between the reference microphone 50 and the physical microphone 80, D(Z) represents the transfer function between the speaker module 40 and the reference microphone 50, and C(Z) represents the transfer function between the speaker module 40 and the physical microphone 70. When the fan module 20 operates at different fan speeds, the resulting wind pressure will also be different, and the wind pressure caused by the rotation of the fan blades will affect the transfer function between the speaker module 40, the reference microphone 50, and the physical microphone 80. Therefore, this invention can calculate the transfer function corresponding to each fan speed in offline mode.

[0060] In step 410, the present invention places a physical microphone 80 at the air outlet of the electronic system 100. The physical microphone 80 is used to acquire the overall noise of the electronic system 100 when it is running in offline mode and outputs a corresponding error signal e(n) to the active noise cancellation controller 60, where d(n) represents the noise signal to be eliminated during the offline operation of the electronic system 100. Since the fan module 20 is the main noise source, the physical microphone 80 can be placed close to the air outlet of the fan module 20, wherein the distance between the reference microphone 50 and the active noise cancellation controller 60 is greater than the distance between the physical microphone 80 and the active noise cancellation controller 60. More specifically, the error signal e(n) output by the physical microphone 80 is related to the difference between the noise signal d(n) and the acquired inverse noise signal y(n), and the smaller the value of the error signal e(n), the better the noise reduction effect.

[0061] In step 430, the adaptive filter 76 measures the transfer function P'(Z) between the reference microphone 50 and the physical microphone 80 while the speaker module 40 is not operating. More specifically, in step 430, the active noise cancellation controller 60 outputs a speaker control signal S. MIC With the speaker module 40 turned off (y(n) value 0), the adaptive filter 76 adjusts the parameter W(Z) of the digital filter 66 based on the broadband noise signal f(n) measured by the reference microphone 50 and the error signal e(n) output by the physical microphone 80. After a predetermined period of adaptive signal processing, the parameter W(Z) of the digital filter 66 converges to a predetermined stable state, at which point the parameter W(Z) of the digital filter 66 can be used as the transfer function P'(Z) between the reference microphone 50 and the physical microphone 80.

[0062] In step 430, the present invention measures the transfer function D'(Z) between the speaker module 40 and the reference microphone 50, and the transfer function C'(Z) between the speaker module 40 and the physical microphone 70 under no-pressure conditions. More specifically, in step 430, the embedded controller 30 outputs a fan control signal S.FG To shut down fan module 20, active noise cancellation controller 60 outputs speaker control signal S. MIC The speaker module 40 provides an inverted noise signal y(n). In offline mode, the inverted noise signal y(n) is white noise used as the test signal, and the adaptive filter 76 adjusts the parameter W(Z) of the digital filter 66 based on the inverted noise signal y(n) provided by the speaker module 40 and the error signal e(n) output by the physical microphone 80. After a predetermined period of adaptive signal processing, the parameter W(Z) of the digital filter 66 converges to a predetermined stable state, at which point the parameter W(Z) of the digital filter 66 can be used as the transfer function D'(Z) between the speaker module 40 and the reference microphone 50 in the absence of wind pressure. Similarly, the adaptive filter 76 adjusts the parameter W(Z) of the digital filter 66 based on the inverted noise signal y(n) provided by the speaker module 40 and the error signal e(n) output by the physical microphone 80. After a predetermined period of adaptive signal processing, the parameter W(Z) of the digital filter 66 will converge to a predetermined stable state. At this point, the parameter W(Z) of the digital filter 66 can be used as the transfer function C'(Z) between the speaker module 40 and the physical microphone 80 in the absence of wind pressure.

[0063] Figure 6 This is a flowchart of the electronic system 100 with heat dissipation and feedforward active noise control functions operating in online mode according to an embodiment of the present invention, which includes the following steps:

[0064] Step 610: Use the reference microphone 50 to acquire the noise generated by the fan module 20 during operation and provide the corresponding wideband noise signal f(n).

[0065] Step 620: The virtual microphone module 80 provides a virtual error signal e'(n) based on the transfer functions P'(Z) and C'(Z), the broadband noise signal f(n), and the phase-inverting noise signal y(n).

[0066] Step 630: The active noise cancellation controller 60, based on the synchronization signal S SYN The number of fan blades in fan module 20 and the motor speed in each mode are obtained, and the relevant speaker control signal S is calculated. MIC The reference signal x(n) is the reference power value.

[0067] Step 640: The active noise cancellation controller 60 calculates the actual single-blade fundamental frequency, actual single-blade harmonic frequency, actual blade passing frequency (BPF), and actual wideband noise spectrum of the fan module 20 based on the broadband noise signal f(n), the virtual error signal e'(n), and the reference signal x(n), and provides the speaker control signal S accordingly. MIC .

[0068] Step 650: The speaker module 40 operates according to the speaker control signal S MIC Generate an inverted noise signal y(n); execute step 610.

[0069] The noise source of the fan module 20 during operation originates from the airflow caused by the motor rotation. Narrow-frequency components may originate from thickness noise caused by volumetric displacement due to fan blade movement, or BPF noise caused by variable load forces on the fan blade surface (including axial lift and fan surface tension). Since BPF and related harmonics are related to pressure disturbances generated when each fan blade passes a fixed reference point, specific narrow-frequency noise is generated when periodic pressure waves are generated at the fan blade tip. On the other hand, when airflow passes over the fan blades, it peels away from the boundary layer or the sides of the blade tips, forming alternating vortices. This phenomenon is called vortex shedding. Vortex shedding causes the instantaneous velocity of the fluid on both sides of the fan blades to differ, resulting in different instantaneous pressures on both sides of the fan blades at different fluid velocities. This causes the fan blades to vibrate, generating specific broadband noise.

[0070] In step 610, the reference microphone 50 acquires the noise caused by the blades of the fan module 20 when it is running in online mode during the operation of the electronic system 100, and provides the corresponding wideband noise signal f(n).

[0071] In step 620, the virtual microphone module 70 provides a virtual error signal e'(n) based on the transfer functions P'(Z) and C'(Z) obtained in offline mode, the broadband noise signal f(n), and the phase-inverse noise signal y(n), where e'(n) = P'(Z)*f(n) + C'(Z)*y(n). As mentioned earlier, P'(Z) is the transfer function between the reference microphone 50 and the physical microphone 80 at a specific fan speed, C'(Z) is the transfer function between the speaker module 40 and the physical microphone 70 in the absence of wind pressure, and D'(Z) is the transfer function between the speaker module 40 and the reference microphone 50 in the absence of wind pressure. The virtual microphone module 70, which operates based on the transfer functions P'(Z) and C'(Z), can simulate the operation of the physical microphone 80, therefore the electronic system 100 of the present invention does not require an additional physical error microphone. In the present invention, the virtual microphone module 70 can be implemented by software or firmware, but this does not limit the scope of the present invention.

[0072] In step 630, the frequency calculator 62 of the active noise cancellation controller 60 can use the synchronization signal S provided by the embedded controller 30. SYN The motor speed, single-blade frequency point, and number of blades of fan module 20 are known, where the value of BPF is the product of the motor speed and the number of blades of fan module 20. Assuming the number of blades in fan module 20 is 37, Table 1 below shows the data calculated by the frequency calculator 62, but this does not limit the scope of the invention. The unit of motor speed is rpm, and the unit of frequency is Hertz.

[0073]

[0074]

[0075] Table 1

[0076] Next, the signal generator 64 of the active noise cancellation controller 60 generates a reference signal x(n) based on the data calculated by the frequency calculator 62. The reference signal x(n) includes information such as the estimated octave, estimated BPF, and sound pressure level spectrum (dBSPL) of the fan module 20 at different motor speeds, thereby determining the speaker control signal S. MIC The reference power value is obtained by adjusting the parameter W(Z) of the digital filter 66, which can change the speaker control signal S. MIC The power value.

[0077] In step 640, the active noise cancellation controller 60 calculates the actual single-blade fundamental frequency, actual single-blade harmonic frequency, actual BPF, and actual wideband noise spectrum of the fan module 20 based on the broadband noise signal f(n), the virtual error signal e'(n), and the reference signal x(n), and provides the speaker control signal S accordingly.MIC To drive the speaker module driver circuit 68 to output the speaker control signal S MIC The speaker module 40 is then driven to provide an inverted noise signal y(n), where W(Z) represents the adjustable operating parameters of the digital filter 66. More specifically, the inverted noise signal y(n) comprises multiple noise cancellation waveforms, which are respectively inverse signals related to the actual single-blade fundamental frequency, the actual single-blade octave, the actual BPF fundamental frequency, the actual BPF octave, and the broadband noise spectrum.

[0078] In step 650, the active noise cancellation controller 60 adjusts the speaker control signal S based on the transfer function D'(Z) between the speaker module 40 and the reference microphone 50 and the transfer function C'(Z) between the speaker module 40 and the physical microphone 70. MIC The characteristics of the signal are as follows. More specifically, the first path compensation transfer function module 71 processes the inverted noise signal y(n) according to the transfer function D'(Z) between the speaker module 40 and the reference microphone 50, which obtains the relevant current fan speed in offline mode, and outputs the corresponding processed inverted noise signal y'(n) to the signal generator 64. The signal generator 64 subtracts the processed inverted noise signal y'(n) from the broadband noise signal f(n) and outputs the corresponding reference signal x(n) to the digital filter 66 and the second path compensation transfer function module 72. Then, the second path compensation transfer function module 72 processes the reference signal x(n) according to the transfer function C'(Z) between the speaker module 40 and the physical microphone 70, which obtains the relevant current fan speed in offline mode, and outputs the corresponding processed reference signal x'(n) to the adaptive filter 76.

[0079] The adaptive filter 76 can perform signal processing on the processed reference signal x'(n) and the virtual error signal e'(n) according to a specific algorithm, thereby adjusting the parameter W(Z) of the digital filter 66. More specifically, the processed reference signal x'(n) includes information such as the motor speed of the fan module 20, the estimated single-blade fundamental frequency, the estimated harmonic frequency, the estimated BPF, and the estimated wind pressure. The adaptive filter 76 then uses the error signal e(n) to calculate the actual single-blade fundamental frequency, the actual harmonic frequency, and the actual BPF, as well as other relevant narrow-band noise information, during the operation of the fan module 20, and adjusts the parameter W(Z) of the digital filter 66 accordingly. In this way, when the digital filter 66 drives the speaker module drive circuit 68 to output the speaker control signal S... MICAt this time, the inverted noise signal y(n) generated by the speaker module 40 reflects the actual operating status of the fan module 20, the wind pressure effect caused by the current fan speed, and the current noise reduction level. More specifically, the inverted noise signal y(n) contains multiple noise cancellation waveforms, which are the inverse signals related to the actual single-blade fundamental frequency, the actual single-blade octave frequency, the actual BPF fundamental frequency, the actual BPF octave frequency, the broadband noise spectrum, and the actual wind pressure, respectively. After signal transmission, the inverted noise signal y(n) generated by the speaker module 40 can effectively cancel the influence of the noise signal d(n), that is, reduce the virtual error signal e'(n) to 0 as much as possible.

[0080] In one embodiment, the adaptive filter 76 may perform signal processing on the processed reference signal x'(n) and the virtual error signal e'(n) according to the Least mean square (LMS) algorithm. However, the algorithm used by the adaptive filter 76 does not limit the scope of the invention.

[0081] In summary, in the electronic system 100 of the present invention with heat dissipation and feedforward active noise control functions, the transfer functions P(Z) between the reference microphone 50 and the physical microphone 80, D(Z) between the speaker module 40 and the reference microphone 50, and C(Z) between the speaker module 40 and the physical microphone 80 are first calculated in offline mode for each fan speed. Then, in online mode, the reference microphone 50 acquires the noise caused by the fan module 20 blades during operation and provides a corresponding broadband noise signal f(n). The virtual microphone module 70 provides a virtual error signal e'(n) based on the transfer function P'(Z) between the reference microphone 50 and the physical microphone 80 at a specific fan speed, the transfer function C'(Z) between the speaker module 40 and the physical microphone 70 under no-pressure conditions, the broadband noise signal f(n), and the anti-phase noise signal y(n). Based on the synchronization signal S... SYN The active noise cancellation controller 60 can calculate the broadband noise generated by the fan module 20 when it runs at a predetermined fan speed, based on the broadband noise signal f(n), the virtual error signal e'(n), and the transfer functions C'(Z) and D'(Z) obtained in offline mode, and then provide the speaker control signal S accordingly. MICThe speaker module 40 is driven so that the inverse noise signal y(n) provided by the speaker module 40 can effectively cancel out the influence of the noise signal d(n). Since the virtual microphone module 70, which operates according to the transfer functions P'(Z) and C'(Z), can simulate the operation of the physical microphone 80, the electronic system 100 of the present invention can provide feedforward active noise control without the need for an additional physical error microphone. The virtual microphone module 70 does not occupy space, and the virtual error signal e'(n) it provides is not interfered with by external noise, thus improving the efficiency of feedforward active noise control.

[0082] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made in accordance with the claims of the present invention should be included within the scope of the present invention.

Claims

1. An electronic system with heat dissipation and feedforward active noise control functions, comprising: A fan module is used to operate according to a fan control signal to provide heat dissipation. An embedded controller is used to provide control signals for the fan; A reference microphone is used to detect the broadband noise generated during the operation of the fan module in order to provide a corresponding broadband noise signal; A speaker module for providing an inverted noise signal based on a speaker control signal; and An active noise cancellation controller is used to: A virtual error signal is provided based on a first transfer function, a second transfer function, the broadband noise signal, and the inverted noise signal; and A loudspeaker control signal is generated based on a synchronization signal, the wideband noise signal, and the virtual error signal; in: The synchronization signal contains information about the structure and operating settings of the fan module; The first transfer function is the transfer function between the reference microphone and a physical microphone when the speaker module is not running; The second transfer function is the transfer function between the speaker module and the physical microphone when the fan module is not running; and The inverted noise signal contains multiple noise cancellation waveforms to counteract the noise generated during the operation of the electronic system; and The physical microphone is located at one of the air vents of the electronic system.

2. The electronic system of claim 1, wherein the active noise cancellation controller is further configured to: The power of the speaker control signal is adjusted based on the broadband noise signal, the virtual error signal, the second transfer function, and a third transfer function, wherein the third transfer function is the transfer function between the speaker module and the reference microphone when the fan module is not running.

3. The electronic system of claim 1, wherein the active noise cancellation controller is further configured to: The first transfer function between the reference microphone and the physical microphone is measured when the speaker module is not running. The second transfer function between the speaker module and the physical microphone was measured when the fan module was not running. A third transfer function between the speaker module and the reference microphone is measured when the fan module is not running. The virtual error signal is obtained based on the first transfer function, the second transfer function, and the third transfer function, wherein the value of the virtual error signal is the product of the first transfer function and the broadband noise signal plus the product of the second transfer function and the inverted noise signal.

4. The electronic system of claim 1, wherein the active noise cancellation controller comprises: A virtual microphone module is used to provide the virtual error signal based on the first transfer function and the second transfer function; A frequency calculator is used to determine, based on the synchronization signal, an estimated single-blade fundamental frequency, an estimated single-blade harmonic frequency, and an estimated blade passage frequency fundamental frequency of the fan module; A signal generator is used to generate a reference signal based on the estimated single-blade fundamental frequency, the estimated single-blade harmonic frequency, and the estimated blade transmission frequency fundamental frequency; and A digital filter is used to perform calculations on the reference signal to determine a reference power value for the loudspeaker control signal.

5. The electronic system of claim 4, wherein the active noise cancellation controller further comprises: An adaptive filter is used to adjust the parameters used by the digital filter when performing operations based on the second transfer function, a third transfer function and the virtual error signal, thereby adaptively adjusting the power value of the speaker control signal.

6. The electronic system of claim 5, wherein: The adaptive filter uses a least mean square algorithm to process the reference signal, the broadband noise signal, and the error signal.

7. The electronic system of claim 4, wherein the active noise cancellation controller further comprises: A first path compensation transfer function module, coupled to the speaker module, receives the anti-phase noise signal, then processes the anti-phase noise signal according to a third transfer function, and outputs the corresponding processed anti-phase noise signal to the signal generator; and A second path compensation transfer function module is coupled to the signal generator to receive the reference signal, then performs signal processing on the reference signal according to the second transfer function, and outputs the corresponding processed reference signal to an adaptive filter.

8. The electronic system of claim 7, wherein the signal generator is further configured to: The wideband noise signal is subtracted from the processed inverted noise signal to provide the reference signal.

9. The electronic system of claim 1, wherein the active noise cancellation controller is further configured to: Based on the synchronization signal, the broadband noise signal, and the error signal, the following parameters are calculated for the fan module operating at a predetermined fan speed: a fundamental frequency of an actual single blade, an overtone of an actual single blade, a fundamental frequency of an actual blade passage frequency, an overtone of an actual blade passage frequency, and an actual broadband noise spectrum; The loudspeaker control signal is generated based on the actual single blade fundamental frequency, the actual single blade harmonic frequency, the actual blade passing frequency fundamental frequency, the actual blade passing frequency harmonic frequency, and the actual broadband noise spectrum.

10. The electronic system of claim 9, wherein the plurality of noise cancellation waveforms are inverse signals relating to the actual single blade fundamental frequency, the actual single blade harmonic frequency, the actual blade passage frequency fundamental frequency, the actual blade passage frequency harmonic frequency, and the broadband noise spectrum.

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