TWI867795B - Inductor driving device and inductor driving method - Google Patents

Abstract

An inductor driving device includes multiple switching elements and a control circuit, wherein an inductor is driven according to switching of the multiple switching elements, and the control circuit is arranged to generate a control signal for controlling the multiple switching elements. In a first mode, the control signal has a constant frequency. In a second mode, the control circuit adjusts a frequency of the control signal and continuously changes a current direction of the inductor, to generate one of multiple audio signals through the inductor.

Description

Inductive drive device and inductive drive method

The present invention relates to a servomotor, and in particular to an inductive drive device and a related inductive drive method used in a servomotor.

For existing servo motors, when the servo motor fails to operate successfully, the user cannot perform troubleshooting on the servo motor based on any information. At this time, the user needs to clearly inform the manufacturer of the operating status of the servo motor so that the manufacturer can guess the reason why the servo motor fails to operate and find a solution to make the servo motor operate normally. Since the above processing process is quite time-consuming, an inductive drive device and a related inductive drive method that can automatically notify the user of the current error status of the servo motor are highly needed.

Therefore, one of the purposes of the present invention is to provide an inductive drive device and a related inductive drive method for a servo motor to solve the above problems.

According to an embodiment of the present invention, an inductor driving device is provided. The inductor driving device includes a plurality of switch elements and a control circuit, wherein an inductor is driven according to the switching of the plurality of switch elements, and the control circuit is used to generate a control signal to control the plurality of switch elements. In a first mode, the control signal has a fixed frequency. In a second mode, the control circuit adjusts a frequency of the control signal and continuously changes a current direction of the inductor to generate one of a plurality of audio signals through the inductor.

According to an embodiment of the present invention, an inductor driving method is provided. The inductor driving method includes: generating a control signal to control a plurality of switch elements; and driving an inductor according to the switching of the plurality of switch elements; wherein in a first mode, the control signal has a fixed frequency; and in a second mode, adjusting a frequency of the control signal and continuously changing a current direction of the inductor to generate one of a plurality of audio signals through the inductor.

According to another embodiment of the present invention, an inductor drive device is provided. The inductor drive device includes a plurality of switch elements and a control circuit, wherein an inductor is driven according to the switching of the plurality of switch elements, and the switch circuit is used to generate a control signal to control the plurality of switch elements. In a first mode, the control signal has a fixed frequency. In a second mode, the control circuit adjusts a frequency of the control signal to generate one of a plurality of audio signals through the inductor, wherein each of the plurality of audio signals is composed by a Morse code.

One of the benefits of the present invention is that the inductive drive device (which is applied to a servo motor) and the related inductive drive method disclosed in the present invention can notify the user of a current alarm state of the servo motor by a corresponding audio signal, wherein the audio signal is generated by the howling of the stator winding included in the servo motor and is composed by Morse code. In addition, when the operating mode of the servo motor is an alarm mode, the current direction of the stator winding of the servo motor is continuously changed to keep the servo motor stationary. During the current direction change operation, multiple switch elements used to drive the servo motor can be operated alternately, which reduces the heat loss of the switch elements and thus improves the reliability of the switch elements.

100: Motor system

10: Proportional integral derivative controller

12: Proportional integral derivative speed controller

14: Inductive drive device

16:Servo motor

18: Position sensor

20: Hall sensor

P_C: Position command

F_P: Feedback position

V_C: speed command

F_V: Feedback speed

VO_C: voltage command

PS_S: Phase sequence signal

SRP,SRV: Subtraction result

CS: Control signal

200: Control circuit

201: Power supply

202: Switching circuit

204: Rotor

VDD: supply voltage

S1~S6: switch components

V_DRV: driving voltage

U,V,W: stator winding

S300~S310,S400,S402,S404,S406,S408,S409,S410,S411,S412,S500,S502: Step

Figure 1 is a schematic diagram of a motor system according to an embodiment of the present invention.

Figure 2 is a schematic diagram of the configuration between the inductive drive device and the servo motor shown in Figure 1 according to an embodiment of the present invention.

Figure 3 is a flow chart of switching between the normal mode and the alarm mode of the servo motor shown in Figure 1 according to an embodiment of the present invention.

Figure 4 is a flow chart of the operation of the control circuit shown in Figure 2 according to an embodiment of the present invention.

Figure 5 is a flow chart of an inductive driving method according to an embodiment of the present invention.

Figure 6 is a schematic diagram of an example of current changes in the alarm mode of the servo motor shown in Figure 1 according to an embodiment of the present invention.

FIG. 1 is a schematic diagram of a motor system 100 according to an embodiment of the present invention. As shown in FIG. 1 , the motor system 100 may include a proportional-integral-derivative (PID) position controller 10 (for the sake of brevity, labeled as “PID position controller” in FIG. 1 ), a proportional-integral-derivative speed controller 12 (for the sake of brevity, labeled as “PID speed controller” in FIG. 1 ), an inductive drive device 14, a servomotor 16, and a position sensor 18, wherein the position sensor 18 is used to perform a closed-loop control for the servomotor 16. Examples of the servo motor 16 may include, but are not limited to, a three-phase alternating current (AC) induction motor, a brushless direct current (DC) motor, a brushed DC motor, and a switched reluctance motor (SRM). For better understanding, in the present embodiment, the servo motor 16 may be a three-phase brushless DC motor. In the case where the servo motor 16 is a three-phase brushless DC motor, the motor system 100 may further include a hall sensor 20, wherein the hall sensor 20 may be used to generate and transmit a phase sequence signal PS_S to the inductive drive device 14 for performing a phase switching operation on the stator of the servo motor 16 through the inductive drive device 14. In some embodiments, the servo motor 16 may be a brushed motor, and the forward rotation/reverse rotation of the servo motor 16 may be controlled by the positive and negative signs of the voltage (or current) input to the servo motor 16.

The PID position controller 10 may be used to receive a position command P_C, receive a feedback position F_P of the servo motor 16 (especially, the rotor of the servo motor 16) from the position sensor 18, subtract the feedback position F_P from the position command P_C to generate a subtraction result SRP, and convert the subtraction result SRP into a speed command V_C. The PID speed controller 12 may be used to receive a speed command V_C from the PID position controller 10, receive a feedback speed F_V of the servo motor 16 from the position sensor 18, subtract the feedback speed F_V from the speed command V_C to generate a subtraction result SRV, and convert the subtraction result SRV into a voltage command VO_C. The inductor drive device 14 can be used to generate a control signal CS according to the voltage command VO_C for driving an inductor (e.g., stator winding) included in the servo motor 16. In addition, in response to the servo motor 16 being in an alarm state, the inductor drive device 14 can adjust the frequency of the control signal CS and continuously change the current direction of the current flowing through the stator winding to generate one of the multiple audio signals through the whistle of the inductor (e.g., stator winding).

For details, please refer to FIG. 2, which is a schematic diagram of the configuration between the inductive drive device 14 and the servo motor 16 shown in FIG. 1 according to an embodiment of the present invention. As shown in FIG. 2, the inductive drive device 14 may include a control circuit 200 and a switch circuit 202, wherein the switch circuit 202 may include a plurality of switch elements S1-S6, and each of the switch elements S1-S6 may be implemented by a transistor. In addition, the switch elements S1-S6 may receive a supply voltage VDD from a power supply 201, wherein the power supply 201 may be implemented by a battery. The servo motor 16 may include a rotor 204 and a stator. The rotor 204 may be a magnet, and the stator may be a three-phase stator winding including a stator winding U, a stator winding V, and a stator winding W.

The control circuit 200 can be used to generate a control signal CS according to the voltage command VO_C to control the opening and closing of the switch elements S1~S6. In response to the switching of the switch elements S1~S6, a driving voltage V_DRV can be generated to drive the servo motor 16 (especially, the stator windings U, V and W of the servo motor 16). That is, the magnetic field angle of the servo motor 16 (such as the angle of the rotor 204) can be changed according to the driving V_DRV to make the servo motor 16 operate. After the servo motor 16 is driven by the driving voltage V_DRV, in response to the servo motor 16 operating smoothly, the operation mode of the servo motor 16 can be a normal mode. For better understanding, it is assumed that the operation mode of the servo motor 16 is initially the normal mode.

In the normal mode, the control signal CS has a fixed frequency (e.g., 20 kHz), and a duty cycle of the control signal CS is adjusted according to the switching of the switch elements S1-S6. For example, the control signal CS can be a pulse width modulation (PWM) signal. In addition, the angle of the rotor 204 can be sequentially changed to 0 degrees, 60 degrees, 120 degrees, 180 degrees, 240 degrees, 300 degrees and back to 0 degrees, 60 degrees, ..., and so on. Specifically, initially, when the angle of the rotor 204 is changed to 0 degrees, the switching elements S1 and S4 are turned on, the switching elements S2, S3, S5, and S6 are turned off (as shown in FIG. 2 ), and the current flows into the stator winding U through the switching element S1, flows out from the stator winding V, and flows back to the power supply 201 through the switching element S4. When the angle of the rotor 204 is changed from 0 degrees to 60 degrees, the switching elements S1 and S6 are turned on, the switching elements S2, S3, S4, and S5 are turned off, and the current flows into the stator winding U through the switching element S1, flows out from the stator winding W, and flows back to the power supply 201 through the switching element S6. When the angle of the rotor 204 is changed from 60 degrees to 120 degrees, the switching elements S3 and S6 are turned on, the switching elements S1, S2, S4 and S5 are turned off, and the current flows into the stator winding V through the switching element S3, flows out of the stator winding W, and flows back to the power supply 201 through the switching element S6.

When the angle of the rotor 204 is changed from 120 degrees to 180 degrees, the switching elements S2 and S3 are turned on, the switching elements S1, S4, S5 and S6 are turned off, and the current flows into the stator winding V through the switching element S3, flows out of the stator winding U, and flows back to the power supply 201 through the switching element S2. When the angle of the rotor 204 is changed from 180 degrees to 240 degrees, the switching elements S2 and S5 are turned on, the switching elements S1, S3, S4 and S6 are turned off, and the current flows into the stator winding W through the switching element S5, flows out of the stator winding U, and flows back to the power supply 201 through the switching element S2. When the angle of the rotor 204 is changed from 240 degrees to 300 degrees, the switching elements S4 and S5 are turned on, the switching elements S1, S2, S3 and S6 are turned off, and the current flows into the stator winding W through the switching element S5, flows out of the stator winding V, and flows back to the power supply 201 through the switching element S4.

When the operation mode of the servo motor 16 is the normal mode, the control circuit 200 can implement an algorithm by loading and executing program code to determine whether the servo motor 16 is in any of a plurality of alarm states ES_1 to ES_M, where "M" is an integer greater than 1 (e.g., M=4). In the alarm state ES_1, a voltage corresponding to the voltage command VO_C exceeds the voltage range of the servo motor 16. In the alarm state ES_2, the rotor 204 of the servo motor 16 is blocked. In the alarm state ES_3, the temperature of the inductive drive device 14 exceeds the operating temperature of the switch elements S1 to S6. In the alarm state ES_4, the position command P_C input to the motor system 100 (especially, the servo motor 16) is lost. The alarm states ES_1~_ES_4 are for illustration purposes only, and the present invention is not limited thereto. It should be noted that the number and type of alarm states ES_1~_ES_M can be adjusted according to actual design considerations.

In response to the servo motor 16 being in any of the alarm states ES_1 to ES_M, the operation mode of the servo motor 16 is switched from the normal mode to an alarm mode. In the alarm mode, the control circuit 200 can adjust the frequency of the control signal CS and keep the duty cycle of the control signal CS unchanged to generate an audio signal among a plurality of audio signals AS_1 to AS_M through the howling of an inductor (e.g., stator windings U, V, and W included in the servo motor 16), wherein the control signal CS can be a pulse frequency modulation (PFM) signal, and the audio signals AS_1 to AS_M correspond to the alarm states ES_1 to ES_M, respectively. For example, the frequency of the control signal CS can be reduced from a fixed frequency (e.g., 20 kHz) in the normal mode to a low frequency audible to the human ear (e.g., 5 kHz).

For each of the alarm states ES_1 to ES_M, an alarm of the servo motor 16 will occur. Therefore, when the servo motor 16 is in the normal mode, the control circuit 200 can be used to determine whether any alarm of the servo motor 16 has occurred. In response to the occurrence of the alarm of the servo motor 16, the control circuit 200 can determine which of the alarm states ES_1 to ES_M a current alarm state of the servo motor 16 is, and generate an audio signal by adjusting the frequency of the control signal CS, wherein the audio signal indicates the current alarm state and is one of the audio signals AS_1 to AS_M.

It should be noted that each of the audio signals AS_1 to AS_M is composed by a Morse code. In the present embodiment, each of the audio signals AS_1 to AS_M can be a combination of a long tone and a short tone. For example, when the number of alarm states ES_1 to ES_M is 8 (i.e., M=8), 8 different combinations of 3 sounds with long and short tones (e.g., 3 long tones, 2 long tones + 1 short tone, 1 long tone + 2 short tones, 1 long tone + 1 short tone + 1 long tone, 1 short tone + 1 long tone + 1 short tone, 1 short tone + 2 long tones, 2 short tones + 1 long tone, and 3 short tones) can be used to generate an alarm. Audio signals AS_1 to AS_8 are generated respectively to inform the user of the current alarm status of the servo motor 16, wherein 8 combinations correspond to the alarm status ES_1 to ES_8 respectively, and there is a first time interval without sound between each sound to allow the user to distinguish between long sounds and short sounds. Each combination will be repeated continuously. In the process of combination repetition, a second time interval without sound will be used to distinguish adjacent combinations, and the second time interval can be longer than the first time interval. For example, when the control circuit 200 generates a pulse frequency modulation signal to generate a combination of 1 long tone + 2 short tones through the stator windings U, V and W of the servo motor 16, a long tone of 1 second, a first time interval of 0.2 seconds, a short tone of 0.2 seconds, a first time interval of 0.2 seconds, a short tone of 0.2 seconds, a second time interval of 1.2 seconds, a next combination with the same sound (i.e., 1 long tone + 2 short tones), ..., and so on can be generated in sequence. For another example, when the number of alarm states ES_1 to ES_M is 16 (ie, M=16), a combination of four sounds with long and short sounds can be used to generate audio signals AS_1 to AS_16 respectively. That is, when the number of sounds to be combined is n, the number of alarm states ES_1 to ES_M can be ²ⁿ (ie, M= ²ⁿ ).

In some embodiments, the amplitude of the sound can be changed without changing the frequency of the control signal CS, so as to distinguish the alarm state of the servo motor 16 by a sound combination with large and small sounds, wherein the sound combination can also be composed of Morse code. Since the operation of the sound combination with large and small sounds is similar to the operation of the sound combination with long and short sounds, for the sake of brevity, similar contents will not be repeated in detail here.

FIG. 3 is a flow chart of switching between the normal mode and the alarm mode of the servo motor 16 shown in FIG. 1 according to an embodiment of the present invention. If the same result can be obtained, the steps do not have to be executed in sequence in full accordance with the flow shown in FIG. 3. For example, the switching operation shown in FIG. 3 can be implemented by the inductive drive device 14 shown in FIG. 1 (especially, the control circuit 200 shown in FIG. 2).

In step S300, after receiving the voltage command VO_C, the control circuit 200 can generate a control signal CS according to the voltage command VO_C to drive the stator windings U, V and W of the servo motor 16, wherein the operation mode of the servo motor 16 is initially the normal mode.

In step S302, the control circuit 200 can determine whether any alarm of the servo motor 16 occurs. If yes, it proceeds to step S304; if not, it proceeds to step S300.

In step S304, the operating mode of the servo motor 16 is switched from the normal mode to the alarm mode.

In step S306, the control circuit 200 determines whether the current alarm state of the servo motor 16 is one of the alarm states ES_1~ES_M.

In step S308, the control circuit 200 generates an audio signal corresponding to the current alarm state among the audio signals AS_1~AS_M by adjusting the frequency of the control signal CS.

In step S310, the control circuit 200 can determine whether the current alarm has been released (for example, the user performs an error elimination operation on the servo motor 16 according to the corresponding audio signal, thereby making the servo motor 16 operate normally). If yes, it goes to step S300; if not, it goes to step S304.

Since those skilled in the art can easily understand the operation of each step shown in Figure 3 through the above instructions, for the sake of brevity, similar contents in this embodiment will not be repeated here.

When the operation mode of the servo motor 16 is the alarm mode, during the process of changing the switching mode of the switch elements S1~S6 (e.g., changing from the switching mode where the current flows from the stator winding U to the stator winding V to another switching mode where the current flows from the stator winding U to the stator winding W) and/or generating the audio signals AS_1~AS_M, the servo motor 16 may rotate, which may cause damage to the servo motor 16. To solve this problem, the control circuit 200 can continuously change the current direction of the stator windings U, V and W of the servo motor 16 to keep the servo motor 16 stationary in the alarm mode.

Specifically, the control circuit 200 can repeatedly reverse the current direction by 180 degrees, so that the current direction changes alternately between the positive direction and the negative direction. Taking the rotor angle of the servo motor 16 as 0 degrees, when the current flows from the stator winding U to the stator winding V (which is regarded as the positive direction of the current direction), the magnetic field direction of the servo motor 16 can be changed to the N pole. In response to the servo motor 16 about to move toward the N pole but not yet starting to move, the control circuit changes the current direction by 180 degrees in the opposite direction so that the current flows from the stator winding V to the stator winding U (which is considered the negative direction of the current direction; that is, the current direction changes from the positive direction to the negative direction, and the rotor angle of the servo motor 16 changes from 0 degrees to 180 degrees), and the magnetic field direction of the servo motor 16 is changed to the S pole. In response to the servo motor 16 about to move to the S pole but not yet starting to move, the control circuit reverses the current direction by 180 degrees so that the current flows from the stator winding U to the stator winding V (that is, the current direction changes from the negative direction to the positive direction, and the rotor angle of the servo motor 16 changes from 180 degrees to 0 degrees), and the magnetic field direction of the servo motor 16 is changed to the N pole. By repeating the above operation (that is, the current direction changes alternately between the positive direction and the negative direction), the servo motor 16 will not rotate in the alarm mode.

In this embodiment, the current direction change operation of the servo motor 16 in the alarm mode can be divided into 6 cases (e.g., cases 1 to 6). In case 1, before entering the alarm mode, the rotor angle of the servo motor 16 is 0 degrees (i.e., the current flows from the stator winding U to the stator winding V), and the control circuit 200 can repeatedly change the rotor angle of the servo motor 16 between 0 degrees and 180 degrees (i.e., the current flows from the stator winding V to the stator winding U) according to the control signal CS. In case 2, before entering the alarm mode, the rotor angle of the servo motor 16 is 60 degrees (i.e., the current flows from stator winding U to stator winding W), and the control circuit 200 can repeatedly change the rotor angle of the servo motor 16 between 60 degrees and 240 degrees (i.e., the current flows from stator winding W to stator winding U) according to the control signal CS. In case 3, before entering the alarm mode, the rotor angle of the servo motor 16 is 120 degrees (i.e., the current flows from stator winding V to stator winding W), and the control circuit 200 can repeatedly change the rotor angle of the servo motor 16 between 120 degrees and 300 degrees (i.e., the current flows from stator winding W to stator winding V) according to the control signal CS. For cases 4 to 6, the rotor angles of the servo motor 16 are 180 degrees, 240 degrees, and 300 degrees, respectively, and can correspond to cases 1 to 3, respectively. For the sake of brevity, the operations of cases 4 to 6 will not be repeated in detail here.

When the current direction changes alternately between the positive direction and the negative direction, the switch elements S1 to S6 can be operated alternately. Taking the above case 1 as an example, when the rotor angle of the servo motor 16 is 0 degrees, the switch elements S1 and S4 are turned on, and when the rotor angle of the servo motor 16 is 180 degrees, the switch elements S2 and S3 are turned on. By alternately operating the switch elements S1 to S6, the heat consumption of the switch elements S1 to S6 can be reduced, which can improve the reliability of the switch elements S1 to S6.

In some embodiments, when the servo motor 16 is a brushed DC motor, the control circuit 200 can also prevent the servo motor 16 from rotating in the alarm mode by alternating the current direction between the positive direction and the negative direction. For the sake of brevity, similar contents of these embodiments will not be repeated in detail.

FIG. 4 is a flow chart of the operation of the control circuit 200 shown in FIG. 2 according to an embodiment of the present invention. If the same result can be obtained, the steps do not have to be executed in sequence in full accordance with the process shown in FIG. 4. In this embodiment, it is assumed that the operation mode of the servo motor 16 is initially in normal mode.

In step S400, determine whether any alarm of the servo motor 16 occurs. If yes, proceed to step S410; if no, proceed to step S402.

In step S402, the operation mode of the servo motor 16 is maintained in normal mode.

In step S404, determine whether the servo motor 16 is a brushed DC motor. If yes, proceed to step S408; if no, proceed to step S406.

In step S406 (for example, the servo motor 16 may be a brushless DC motor), the phase sequence signal PS_S is received to perform commutation operation on the stator windings U, V and W of the servo motor 16.

In step S408 (for example, the servo motor 16 may be a brushed DC motor), the forward/reverse rotation of the servo motor 16 is controlled by the positive and negative signs of the voltage (or current) input to the servo motor 16.

In step S409, a control signal CS is generated according to the voltage command VO_C, wherein the frequency of the control signal CS is fixed (e.g., 20 kHz), and the switching of the switch elements S1~S6 can be controlled by adjusting the duty cycle of the control signal CS to drive the servo motor 16 (especially, the stator windings U, V and W). For example, the control signal CS can be a pulse width modulation signal.

In step S410, the operating mode of the servo motor 16 is switched from the normal mode to the alarm mode.

In step S411, a control signal CS is generated according to the voltage command VO_C, wherein the frequency of the control signal CS can be adjusted and the duty cycle of the control signal CS can be kept unchanged to generate audio signals AS_1~AS_M through the howling of the inductance (such as stator windings U, V and W), and the control signal CS can be a pulse frequency modulated signal. For example, the frequency of the control signal CS can be reduced from a fixed frequency (such as 20 kHz) in the normal mode to a low frequency audible to the human ear (such as 5 kHz).

In step S412, the current direction of the current flowing through the stator windings U, V and W is repeatedly reversed by 180 degrees, so that the current direction changes alternately between the positive direction and the negative direction.

Since those skilled in the art can easily understand the operation of each step shown in Figure 4 through the above instructions, for the sake of brevity, similar contents in this embodiment will not be repeated here.

FIG. 5 is a flow chart of an inductive driving method according to an embodiment of the present invention. If the same result can be obtained, the steps do not have to be performed in sequence in full accordance with the flow shown in FIG. 5. For example, the inductive driving method shown in FIG. 5 can be implemented by the inductive driving device 14 shown in FIG. 1 (especially, the control circuit 200 shown in FIG. 2).

In step S500, a control signal CS is generated to control the switch elements S1~S6.

In step S502, the inductor (e.g., stator windings U, V, and W) is driven according to the switching of the switch elements S1-S6, wherein in the normal mode, the control signal CS has a fixed frequency (e.g., 20 kHz); and in the alarm mode, the frequency of the control signal CS is adjusted (e.g., reduced to a low frequency audible to the human ear, such as 5 kHz) and the current direction of the stator windings U, V, and W is continuously changed to generate audio signals AS_1-AS_M through the howling of the stator windings U, V, and W.

Since those skilled in the art can easily understand the operation of each step shown in Figure 5 through the above instructions, for the sake of brevity, similar contents in this embodiment will not be repeated here.

FIG. 6 is a schematic diagram of an example of current change in the alarm mode of the servo motor 16 shown in FIG. 1 according to an embodiment of the present invention, wherein the horizontal axis represents time (expressed as "T") and the vertical axis represents the current magnitude (expressed as "A"). In this embodiment, the above-mentioned case 1 (i.e., the rotor angle of the servo motor 16 repeatedly changes between 0 degrees and 180 degrees) is taken as an example. As shown in FIG. 6, during the time interval between time point t1 and time point t2, the current flows from the stator winding U to the stator winding V, and the current continuously accumulates in the stator winding V in the positive direction. During the time interval between time point t2 and time point t3, the current gradually dissipates in the stator winding V. During the time interval between time point t3 and time point t4, the current flows from the stator winding V to the stator winding U, and the current continuously accumulates in the stator winding U in the negative direction. During the time interval between time point t4 and time point t5, the current gradually dissipates in the stator winding U. In this way, the current direction will change repeatedly by 180 degrees in the opposite direction, so that the current direction changes alternately between the positive direction and the negative direction, and thus the rotor angle of the servo motor 16 changes repeatedly between 0 degrees and 180 degrees, so that the servo motor 16 can remain stationary in the alarm mode. Since the current changes in the above cases 2 to 6 are similar to the current changes in case 1, they will not be repeated in detail here.

In summary, the inductive drive device (applied to a servo motor) and the related inductive drive method disclosed in the present invention can notify a user of a current alarm state of the servo motor by a corresponding audio signal, wherein the audio signal is generated by the howling of the stator winding included in the servo motor and is composed by Morse code. In addition, when the operation mode of the servo motor is an alarm mode, the current direction of the stator winding of the servo motor is continuously changed to keep the servo motor stationary. During the current direction change operation, multiple switch elements used to drive the servo motor can be operated alternately, which reduces the heat loss of the switch elements and thus improves the reliability of the switch elements.

The above is only the preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the patent application of the present invention shall fall within the scope of the present invention.

S500, S502: Steps

Claims (23)

An inductor driving device includes: a plurality of switch elements, wherein an inductor is driven according to the switching of the plurality of switch elements; a control circuit for generating a control signal to control the plurality of switch elements; wherein in a first mode, the control signal has a fixed frequency; and in a second mode, the control circuit adjusts a frequency of the control signal and continuously changes a current direction of the inductor to generate one of a plurality of audio signals through the inductor. An inductor drive device as described in item 1 of the patent application, wherein the inductor is included in a servo motor. As described in item 2 of the patent application, an inductive drive device, wherein an operation mode of the servo motor is initially the first mode; in response to the servo motor being in one of a plurality of alarm states, the operation mode of the servo motor is switched from the first mode to the second mode; and the plurality of audio signals correspond to the plurality of alarm states respectively. As described in item 3 of the patent application scope, the control circuit is further used to determine whether an alarm of the servo motor occurs; and in response to the occurrence of the alarm of the servo motor, the control circuit determines which alarm state of the servo motor belongs to among the multiple alarm states, and generates an audio signal corresponding to the alarm state. The inductive drive device as described in item 3 of the patent application scope, wherein the control circuit is further used to receive a voltage command and generate the control signal according to the voltage command, and the multiple alarm states include an alarm state corresponding to a voltage of the voltage command exceeding a voltage range of the servo motor. As described in item 3 of the patent application scope, the multiple alarm states include an alarm state in which a rotor of the servo motor is blocked. As described in item 3 of the patent application scope, the multiple alarm states include an alarm state in which a temperature of the inductive drive device exceeds an operating temperature of the multiple switch elements. An inductive drive device as described in item 3 of the patent application, wherein the multiple alarm states include an alarm state in which a position command input to the servo motor is lost. As described in the first item of the patent application scope, the inductor driving device, wherein in the second mode, the control circuit repeatedly changes the current direction of the inductor by 180 degrees in the opposite direction, so that the current direction of the inductor changes alternately in a positive direction and a negative direction. An inductive drive device as described in Item 1 of the patent application, wherein in the second mode, the control circuit maintains a duty cycle of the control signal unchanged. An inductive drive device as described in item 1 of the patent application, wherein each of the multiple audio signals is composed of a Morse code. An inductor driving method includes: generating a control signal to control a plurality of switch elements; and driving an inductor according to the switching of the plurality of switch elements; wherein in a first mode, the control signal has a fixed frequency; and in a second mode, a frequency of the control signal is adjusted and a current direction of the inductor is continuously changed to generate one of a plurality of audio signals through the inductor. An inductor driving method as described in item 12 of the patent application, wherein the inductor is included in a servo motor. As described in item 13 of the patent application, an operation mode of the servo motor is initially the first mode; and the induction driving method further comprises: in response to the servo motor being in one of a plurality of alarm states, switching the operation mode of the servo motor from the first mode to the second mode; wherein the plurality of audio signals correspond to the plurality of alarm states respectively. The inductive driving method described in item 14 of the patent application further includes: determining whether an alarm of the servo motor occurs; and in response to the occurrence of the alarm of the servo motor, determining which alarm state of the servo motor belongs to among the multiple alarm states, and generating an audio signal corresponding to the alarm state. The inductive driving method as described in Item 14 of the patent application further includes: receiving a voltage command and generating the control signal according to the voltage command; wherein the multiple alarm states include an alarm state corresponding to a voltage of the voltage command exceeding a voltage range of the servo motor. As described in the inductive driving method of item 14 of the patent application, the multiple alarm states include an alarm state that a rotor of the servo motor is blocked. As described in the inductive driving method of item 14 of the patent application, an inductive driving device includes the plurality of switch elements, and the plurality of alarm states include an alarm state in which a temperature of the inductive driving device exceeds an operating temperature of the plurality of switch elements. As described in the inductive driving method of claim 14, the multiple alarm states include an alarm state in which a position command input to the servo motor is lost. The inductor driving method as described in Item 12 of the patent application scope further includes: in the second mode, the current direction of the inductor is repeatedly changed in the opposite direction by 180 degrees, so that the current direction of the inductor changes alternately in a positive direction and a negative direction. The inductive driving method as described in Item 12 of the patent application scope further includes: in the second mode, maintaining a working cycle of the control signal unchanged. An inductive driving method as described in Item 12 of the patent application, wherein each of the multiple audio signals is composed of a Morse code. An inductor drive device includes: a plurality of switch elements, wherein an inductor is driven according to the switching of the plurality of switch elements; a control circuit for generating a control signal to control the plurality of switch elements; wherein in a first mode, the control signal has a fixed frequency; and in a second mode, the control circuit adjusts a frequency of the control signal to generate one of a plurality of audio signals through the inductor; wherein the inductor is included in a servo motor, the plurality of audio signals respectively correspond to a plurality of alarm states of the servo motor, and each of the plurality of audio signals is composed by a Morse code to distinguish the plurality of alarm states.

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