Motor lock system

Abstract

This invention discloses a motor lock-up system. A closed-loop control circuit outputs an initial duty cycle signal based on the current speed and the target speed. A drive circuit outputs a drive signal to the motor based on the initial duty cycle signal to control motor operation. A lookup table operation circuit searches a lookup table for two reference duty cycles corresponding to two reference speeds that are identical to both the current and target speeds. The lookup table operation circuit calculates the difference between the two found reference duty cycles. A speed feedback control circuit compensates for this difference to the initial duty cycle signal, outputting a final duty cycle signal to the drive circuit. The drive circuit controls motor operation based on the final duty cycle signal.

Description

Technical Field

[0001] This invention relates to motors, and more particularly to a motor locking system. Background Technology

[0002] In electronic devices such as laptops, fan motors are used to cool heat-generating components such as processors. During the cooling process, the fan motor's speed needs to be precisely controlled to ensure optimal cooling performance.

[0003] However, when the motor transitions from high to low speed or vice versa, the inertial force of the fan must first be counteracted before it can continue to catch up with the target speed. Inertial force is difficult to quantify, so the duty cycle of the drive signal used to control the motor's rotation may be too low or too high, requiring a significant amount of time to catch up. Because the fan has inertia, its speed will lag behind the duty cycle considerably. When it catches up with the target speed, the current duty cycle is often lower than the duty cycle corresponding to the target speed (catching up from a lower speed) or higher than the duty cycle corresponding to the target speed (catching up from an higher speed). Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a motor lock-up system, applicable to fans, which include a motor, addressing the shortcomings of existing technologies. The motor lock-up system includes a speed detection circuit, a closed-loop control circuit, a lookup table operation circuit, a drive circuit, and a speed feedback control circuit. The speed detection circuit is configured to detect the current speed of the motor. The closed-loop control circuit is connected to an external speed indicator circuit. The closed-loop control circuit is configured to receive a target speed from the external speed indicator circuit and the current speed from the speed detection circuit, and output an initial duty cycle signal based on the current speed and the target speed. The lookup table operation circuit is connected to the speed detection circuit. The lookup table operation circuit is configured to store a lookup table. The lookup table operation circuit stores multiple reference speeds and multiple reference duty cycles corresponding to the multiple reference speeds in the lookup table. The lookup table operation circuit receives the target speed from the external speed indicator circuit and the current speed from the speed detection circuit, and searches the lookup table for two reference speeds that are the same as the current speed and the target speed, respectively, defining them as a current duty cycle and a target duty cycle. The lookup table operation circuit calculates and outputs the difference between the current duty cycle and the target duty cycle as a compensation cycle. The drive circuit connects the closed-loop control circuit, the lookup table operation circuit, and the motor. The drive circuit is configured to output a drive signal to the motor based on the initial duty cycle signal to control the motor's operation, gradually bringing the motor's current speed closer to the target speed. The speed feedback control circuit is connected to the lookup table operation circuit. The speed feedback control circuit is configured to compensate the initial duty cycle signal based on the compensation period, outputting a final duty cycle signal to the drive circuit. When the drive circuit receives the final duty cycle signal, it controls the motor's operation accordingly.

[0005] In one embodiment, the motor locking system further includes a position detection circuit. The position detection circuit is connected to the motor and the speed detection circuit. The position detection circuit is configured to detect the position of the motor rotor and output a position detection signal, and the speed detection circuit determines the current speed of the motor based on the position detection signal.

[0006] In one embodiment, when the lookup table operation circuit determines that the absolute value of the compensation period reaches a default period difference, the speed feedback control circuit compensates for the working period of the initial working period signal based on the compensation period and the default period difference, so as to output the final working period signal.

[0007] In one embodiment, the lookup table operation circuit calculates the ratio of the compensation period to one cycle of the target duty cycle. The speed feedback control circuit compensates for the initial duty cycle signal based on the cycle ratio to output the final duty cycle signal.

[0008] In one embodiment, when the lookup table operation circuit determines that the cycle ratio has reached a default ratio, it calculates and outputs the compensation cycle, and the speed feedback control circuit compensates the initial working cycle signal according to the compensation cycle.

[0009] In one embodiment, the lookup table operation circuit determines the size of the default ratio based on fan information related to the inertia magnitude.

[0010] In one embodiment, the lookup table operation circuit determines whether the period ratio has reached a default ratio to generate a compensation start signal. The compensation start signal indicates that compensation of the initial working cycle signal begins when the period ratio reaches the default ratio.

[0011] In one embodiment, when the current speed of the motor is greater than the target speed, the speed feedback control circuit reduces the working period of the initial working period signal to output the final working period signal; however, when the current speed of the motor is less than the target speed, the speed feedback control circuit increases the working period of the initial working period signal to output the final working period signal.

[0012] In one embodiment, the lookup table operation circuit establishes a speed curve based on multiple current speeds of the motor at multiple time points and the target speed.

[0013] In one embodiment, the lookup table operation circuit establishes a current working cycle curve based on multiple current working cycles at multiple time points.

[0014] As described above, the present invention provides a motor lock-up system, which, before the current speed of the fan reaches the target speed (for example, when the difference between the current speed and the target speed reaches a preset ratio), compensates the initial working cycle signal based on the difference between the current speed and the target speed to output a final working cycle signal for controlling the fan operation, so that the fan can quickly reach the target speed and enter a steady state.

[0015] To further understand the features and technical content of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are for reference and illustration only and are not intended to limit the present invention. Attached Figure Description

[0016] Figure 1 This is a block diagram of a motor lock-rotor system according to an embodiment of the present invention.

[0017] Figure 2 The waveform diagram is shown for the motor lock-rotor system according to an embodiment of the present invention.

[0018] Figure 3 The waveform diagram is shown for the motor lock-rotor system according to an embodiment of the present invention.

[0019] Figure 4The waveform diagram is shown for the motor lock-rotor system according to an embodiment of the present invention.

[0020] Figure 5 The waveform diagram is shown for the motor lock-rotor system according to an embodiment of the present invention. Detailed Implementation

[0021] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of the present invention. Furthermore, the accompanying drawings of the present invention are for simple illustrative purposes only and are not depictions of actual dimensions, as stated in advance. The following embodiments will further describe the relevant technical content of the present invention in detail, but the disclosed content is not intended to limit the scope of protection of the present invention. In addition, the term "or" as used herein may, depending on the actual situation, include any combination of any one or more of the associated listed items.

[0022] Please see Figures 1 to 5 ,in Figure 1 This is a block diagram of a motor lock-up system according to an embodiment of the present invention;

[0023] Figures 2 to 5 The waveform diagram is shown for the motor lock-rotor system according to an embodiment of the present invention.

[0024] The motor lock-rotor system of this invention may include, as in the following embodiments: Figure 1 The speed detection circuit 10, closed-loop control circuit 20, lookup table operation circuit 30, drive circuit 40, speed feedback control circuit 50, and position detection circuit 60 shown can be applied to fan 90. Fan 90 includes a motor.

[0025] The position detection circuit 60 can be connected to the motor of the fan 90 and the speed detection circuit 10. The position detection circuit 60 can detect the position of the rotor of the motor of the fan 90 and output a position detection signal PSS to the speed detection circuit 10. For example, the position detection circuit 60 can include a Hall sensor. The speed detection circuit 10 can determine the current speed RR of the motor of the fan 90 based on the position detection signal PSS.

[0026] The closed-loop control circuit 20 can be connected to an external speed indicator circuit (not shown) and a speed feedback control circuit 50. The closed-loop control circuit 20 can receive the target speed TR of the fan 90 motor from the external speed indicator circuit and the current speed RR of the fan 90 motor from the speed detection circuit 10.

[0027] The closed-loop control circuit 20 can determine the working period of the initial working period signal DTOS based on the current speed RR and the target speed TR, and output the initial working period signal DTOS to the speed feedback control circuit 50.

[0028] The drive circuit 40 can be connected to the closed-loop control circuit 20 and the motor of the fan 90. The drive circuit 40 can receive the initial duty cycle signal DTOS from the closed-loop control circuit 20, and output (multiple) drive signals DRS to the bridge circuit of the fan 90 (multiple transistors, such as one or more upper bridge transistors and one or more lower bridge transistors) according to the initial duty cycle signal DTOS to drive the bridge circuit, thereby controlling the operation of the motor connected to the bridge circuit, so that the current speed RR of the fan 90 motor gradually increases or decreases to close to the target speed TR indicated by the external speed indicator circuit.

[0029] It is worth noting that the lookup table operation circuit 30 can be connected to the speed detection circuit 10 and the speed feedback control circuit 50. The lookup table operation circuit 30 can store a lookup table containing multiple reference speeds, and multiple reference duty cycles required for the motor speed of the fan 90 to reach each of these reference speeds in the environment in which the fan 90 is located. That is, multiple reference duty cycles correspond to multiple reference speeds. The lookup table stored in the lookup table operation circuit 30 can be updated according to actual needs.

[0030] The lookup table operation circuit 30 can receive the current speed RR of the fan 90 motor from the speed detection circuit 10. The lookup table operation circuit 30 can find the reference working cycle corresponding to the reference speed that is equal to the current speed RR of the fan 90 motor from the lookup table, and use it as the current working cycle.

[0031] Additionally, the lookup table operation circuit 30 can receive the target speed TR from an external speed indicator circuit (not shown). The lookup table operation circuit 30 can search the lookup table for the reference duty cycle corresponding to the reference speed that is equal to the target speed TR, and use it as the target duty cycle.

[0032] The lookup table operation circuit 30 can be connected to the speed feedback control circuit 50. The lookup table operation circuit 30 can calculate the difference between the current working cycle and the target working cycle, as the required compensation cycle DRFE for the current period, for example... Figure 3 The current working cycle is shown as the required compensation / input working cycle. The lookup table operation circuit 30 can output this compensation cycle DRFE to the speed feedback control circuit 50.

[0033] The speed feedback control circuit 50 can compensate the working cycle of the initial working cycle signal DTOS received from the closed-loop control circuit 20 based on the compensation period DRFE received from the lookup table operation circuit 30, so as to output the final working cycle signal FDTS to the drive circuit 40.

[0034] In detail, when the current speed RR of the fan 90 motor is greater than the target speed TR, the speed feedback control circuit 50 reduces the duty cycle of the initial duty cycle signal DTOS to output the final duty cycle signal FDTS. That is, the duty cycle of the final duty cycle signal FDTS is less than the duty cycle of the initial duty cycle signal DTOS.

[0035] Conversely, when the current speed RR of the fan 90 motor is less than the target speed TR, the speed feedback control circuit 50 increases the duty cycle of the initial duty cycle signal DTOS to output the final duty cycle signal FDTS. That is, the duty cycle of the final duty cycle signal FDTS is greater than the duty cycle of the initial duty cycle signal DTOS.

[0036] When the drive circuit 40 receives the final working cycle signal FDTS from the speed feedback control circuit 50, the drive circuit 40 no longer uses the initial working cycle signal DTOS but the final working cycle signal FDTS to output the drive signal DRS to the bridge circuit connected to the motor of the fan 90 to drive the bridge circuit, thereby controlling the motor of the fan 90 to run.

[0037] For example, the lookup table operation circuit 30 can calculate the difference between the current working cycle and the target working cycle as the compensation period DRFE, and determine whether the absolute value of the compensation period DRFE has reached a default period difference value. When the lookup table operation circuit 30 determines that the absolute value of the current compensation period DRFE has reached this default period difference value, the lookup table operation circuit 30 determines to start compensation. This default period difference value can depend on the target working cycle corresponding to the target speed TR. For example, this default period difference value can be 1 / N of the target working cycle, such as, but not limited to, 1 / 4, 1 / 8, 1 / 16, or 1 / 32 (i.e., N equals 4, 8, 16, or 32).

[0038] When the lookup table operation circuit 30 determines that compensation should begin, it outputs the absolute value of the current compensation period DRFE and the default period difference to the speed feedback control circuit 50. The speed feedback control circuit 50 can compensate for the working period of the initial working period signal DTOS based on the absolute value of the current compensation period DRFE and the default period difference, and output the final working period signal FDTS to the drive circuit 40.

[0039] Alternatively, the lookup table operation circuit 30 can calculate the ratio of the compensation period DRFE (i.e., the difference between the current working cycle and the target working cycle) to the target working cycle as a cycle ratio. When the lookup table operation circuit 30 determines that the current cycle ratio has reached a default ratio, that is, when the difference between the current working cycle and the target working cycle reaches 1 / N of the target working cycle, the lookup table operation circuit 30 determines to start compensation. N mentioned herein can be any suitable value, such as 4, 8, 16, or 32, and 1 / N can be, for example, but not limited to, 1 / 4, 1 / 8, 1 / 16, or 1 / 32.

[0040] When the lookup table operation circuit 30 determines that compensation should begin, it outputs the difference between the current working cycle and the target working cycle as the compensation period DRFE to the speed feedback control circuit 50. The speed feedback control circuit 50 can compensate for the working cycle of the initial working cycle signal DTOS based on the compensation period DRFE, and output the final working cycle signal FDTS to the drive circuit 40.

[0041] The drive circuit 40 switches multiple transistors (e.g., the first upper-bridge transistor, the first lower-bridge transistor, the second upper-bridge transistor, and the second lower-bridge transistor) of the bridge circuit on or off according to the final duty cycle signal FDTS. In this way, the current duty cycle of the fan 90 motor approaches the target duty cycle more quickly, and the duty cycle stabilizes earlier, allowing the fan 90 to operate stably.

[0042] The lookup table operation circuit 30 can determine the aforementioned preset ratio based on information about the fan 90 related to its inertia (such as the weight and size of the fan 90). For example, the smaller the size or weight of the fan 90, the smaller its inertia, and the shorter the compensation time required; therefore, the preset ratio is set lower (e.g., 1 / N is 1 / 32). Conversely, the larger the size or weight of the fan 90, the greater its inertia, and the longer the compensation time required; therefore, the preset ratio is larger (e.g., 1 / N is 1 / 4).

[0043] The compensation start signal is generated when the ratio of the difference between the target work cycles and the target work cycles reaches a preset ratio. The compensation start signal indicates the time point at which compensation begins, for example... Figure 2 The compensation start signal DFRS shown is as follows: Figure 4 The compensation start signal DFRS1 shown is as follows: Figure 5 The compensation start signal DFRS2 is shown.

[0044] Meanwhile, the speed feedback control circuit 50 compensates the initial duty cycle signal DTOS based on the compensation period DRFE to output the final duty cycle signal FDTS, causing the current speed of the fan 90 motor to start chasing the target speed TR. For example... Figure 4The tracking signal CLPS1 indicates that the motor's current speed gradually decreases to near the target speed TR, until it finally reaches the target speed TR. For example... Figure 5 The tracking signal CLPS2 indicates that the motor's current speed gradually increases to approach the target speed TR, until it finally reaches the target speed TR. Figure 4 and Figure 5 In this context, RPMS1 / RPMS2 and DUTYS1 / DUTYS2 represent the current speed signal and the current working cycle signal, respectively.

[0045] The lookup table operation circuit 30 can, based on multiple current speeds RR and target speed TR of the motor at multiple time points, perform operations such as... Figure 2 The diagram shows the establishment of a speed curve in a speed curve graph. The lookup table operation circuit 30 can, based on multiple current operating cycles at multiple time points, as shown... Figure 2 The diagram shows the establishment of a current work cycle curve in the current work cycle curve graph.

[0046] In summary, the present invention provides a motor lock-up system that, before the current speed of the fan reaches the target speed (for example, when the difference between the current speed and the target speed reaches a preset ratio), compensates the initial working cycle signal based on the difference between the current speed and the target speed to output a final working cycle signal for controlling the fan operation, so that the fan can quickly reach the target speed and enter a steady state.

[0047] The above-disclosed content is only a preferred embodiment of the present invention and is not intended to limit the claims of the present invention. Therefore, all equivalent technical changes made based on the description and drawings of the present invention are included in the claims of the present invention.

Claims

1. A motor locking system, suitable for a fan, the fan comprising a motor, characterized in that, The motor locking system includes: A speed detection circuit is configured to detect the current speed of the motor; A closed-loop control circuit is connected to an external speed indicator circuit. The closed-loop control circuit is configured to receive a target speed from the external speed indicator circuit and the current speed from the speed detection circuit, and output an initial duty cycle signal based on the current speed and the target speed. A lookup table operation circuit, connected to the speed detection circuit, is configured to store a lookup table. The lookup table stores multiple reference speeds and multiple reference working cycles corresponding to the multiple reference speeds. The target speed is received from the external speed indication circuit and the current speed is received from the speed detection circuit. The circuit searches the lookup table for two reference working cycles corresponding to the two reference speeds that are the same as the current speed and the target speed, respectively, and defines them as the current working cycle and the target working cycle, respectively. The difference between the current working cycle and the target working cycle is calculated and output as the compensation cycle. A drive circuit is connected to the closed-loop control circuit, the lookup table operation circuit, and the motor. The drive circuit is configured to output a drive signal to the motor according to the initial working cycle signal to control the operation of the motor, so that the current speed of the motor gradually approaches the target speed. as well as A speed feedback control circuit is connected to the lookup table operation circuit. The speed feedback control circuit is configured to compensate the initial working cycle signal according to the compensation period, and output the final working cycle signal to the drive circuit. When the drive circuit receives the final working cycle signal, it controls the motor to operate according to the final working cycle signal. The lookup table operation circuit is configured to calculate the proportion of the compensation period to the target working period as a period ratio. Specifically, when the lookup table operation circuit determines that the current cycle ratio has reached a default ratio, the lookup table operation circuit is configured to determine to start compensation. Specifically, when the lookup table operation circuit determines that compensation should begin, the lookup table operation circuit is configured to output the difference between the current working cycle and the target working cycle as the compensation cycle to the speed feedback control circuit.

2. The motor locking system according to claim 1, characterized in that, The motor locking system also includes: A position detection circuit, connected to the motor and the speed detection circuit, is configured to detect the position of the motor rotor and output a position detection signal. The speed detection circuit determines the current speed of the motor based on the position detection signal.

3. The motor locking system according to claim 1, characterized in that, When the lookup table operation circuit determines that the absolute value of the compensation period reaches the default period difference, the speed feedback control circuit compensates for the working period of the initial working period signal based on the compensation period and the default period difference, so as to output the final working period signal.

4. The motor locking system according to claim 1, characterized in that, The lookup table operation circuit determines the size of the preset ratio based on the information of the fan related to the magnitude of inertia.

5. The motor locking system according to claim 1, characterized in that, When the current speed of the motor is greater than the target speed, the speed feedback control circuit reduces the working period of the initial working period signal to output the final working period signal. However, when the current speed of the motor is less than the target speed, the speed feedback control circuit increases the working period of the initial working period signal to output the final working period signal.

6. The motor locking system according to claim 1, characterized in that, The lookup table operation circuit establishes a speed curve based on the current speed of the motor at multiple time points and the target speed.

7. The motor locking system according to claim 1, characterized in that, The lookup table operation circuit establishes a current working cycle curve based on the motor's current working cycles at multiple time points.

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