Overcurrent detection method and device, servo driver and readable storage medium

Abstract

The application provides an overcurrent detection method and device, a servo driver and a readable storage medium. The overcurrent detection method comprises the following steps: acquiring a first phase current, a second phase current and a first protection threshold; determining a conversion relationship between a third phase current and the first phase current and the second phase current based on the fact that the vector sum of the first phase current, the second phase current and the third phase current is zero; determining a second protection threshold and a third protection threshold according to the conversion relationship and the first protection threshold; and performing overcurrent detection according to the first phase current, the second phase current, the first protection threshold, the second protection threshold and the third protection threshold; wherein the conversion relationship is used to indicate an expression of the third phase current with respect to the first phase current and the second phase current.

Description

Technical Field

[0001] This invention relates to the field of overcurrent detection technology, and more specifically, to an overcurrent detection method and apparatus, a servo driver, and a readable storage medium. Background Technology

[0002] Overcurrent detection is a common method to ensure the safe operation of servo drives. Currently, due to cost considerations, overcurrent detection in servo drives often employs two-phase current sampling. Two-phase overcurrent protection can be achieved through a comparison module, while the third-phase current is calculated via an interrupt service function before overcurrent protection is implemented. However, this overcurrent protection method has a significant delay, reducing the accuracy and speed of overcurrent detection. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0004] Therefore, the first aspect of the present invention is to provide an overcurrent detection method.

[0005] A second aspect of the present invention is to provide an overcurrent detection device.

[0006] A third aspect of the present invention is to provide another overcurrent detection device.

[0007] A fourth aspect of the present invention is to provide a servo driver.

[0008] The fifth aspect of the invention is to provide another servo driver.

[0009] The sixth aspect of the present invention is to provide a readable storage medium.

[0010] In view of this, according to one aspect of the present invention, an overcurrent detection method is proposed, the method comprising: acquiring a first phase current, a second phase current, and a first protection threshold; determining a conversion relationship between the third phase current and the first and second phase currents based on the vector sum of the first phase current, the second phase current, and the third phase current being zero; determining a second protection threshold and a third protection threshold according to the conversion relationship and the first protection threshold; and performing overcurrent detection based on the first phase current, the second phase current, the first protection threshold, the second protection threshold, and the third protection threshold; wherein the conversion relationship is used to indicate the expression of the third phase current with respect to the first phase current and the second phase current.

[0011] The overcurrent detection method provided by this invention is used to detect overcurrent of three-phase current, namely the third phase current, the second phase current and the first phase current, so as to realize overcurrent protection of three-phase current.

[0012] Specifically, in the overcurrent detection method provided by this invention, during the overcurrent protection of three-phase current, a set three-phase current protection threshold, namely the first protection threshold, is obtained, and the second-phase current and the first-phase current are sampled and detected to obtain the current sample values ​​of the second-phase current and the first-phase current. Based on this, a third protection threshold and a second protection threshold are determined according to the obtained first protection threshold and first-phase current.

[0013] Specifically, the vector sum of the third-phase current, the second-phase current, and the first-phase current is zero, i.e., third-phase current + second-phase current + first-phase current = 0. Based on this, and given that third-phase current + second-phase current + first-phase current = 0, the conversion relationship between the third-phase current and the second and first-phase currents can be determined, i.e., the expression for the third-phase current with respect to the second and first-phase currents is determined: third-phase current = -second-phase current - first-phase current. Furthermore, during overcurrent protection, the third-phase current must satisfy the protection condition: the negative of the first protection threshold is less than the third-phase current, and the third-phase current is less than the first protection threshold. Therefore, based on the above conversion relationship, substituting the expression for the third-phase current with respect to the second and first-phase currents into the above protection condition, two sets of correspondences between the second-phase current, the first-phase current, and the aforementioned first protection threshold can be obtained. Further, based on these two sets of correspondences between the second-phase current, the first-phase current, and the aforementioned first protection threshold, the two corresponding protection thresholds, namely the third protection threshold and the second protection threshold, can be obtained.

[0014] Furthermore, based on the determined third and second protection thresholds, and the obtained first protection threshold, second phase current, and first phase current, overcurrent detection is performed on the three-phase current. Specifically, overcurrent detection is performed on the first phase current based on the aforementioned first protection threshold, and overcurrent detection is performed on the second phase current based on the determined third and second protection thresholds. The first protection threshold remains constant, while the third and second protection thresholds change with the sampled value of the first phase current. In other words, in the overcurrent detection method provided by this invention, during the overcurrent protection of the three-phase current, the protection threshold for the first phase current remains constant, and the protection threshold for the second phase current is updated in real time based on the sampled value of the first phase current. It can be understood that the vector sum of the third phase current, the second phase current, and the first phase current is zero; therefore, the change in the value of the first phase current is related to the value of the third phase current. Thus, when overcurrent protection is performed on the second phase current based on the determined third and second protection thresholds, overcurrent protection of the third phase current can also be achieved. In this way, overcurrent protection for three-phase current can be achieved by sampling only two-phase current, which reduces the cost of overcurrent detection, reduces the delay of overcurrent protection, and improves the accuracy and speed of overcurrent detection.

[0015] The overcurrent detection method according to the present invention may also have the following additional technical features:

[0016] In some technical solutions, optionally, a second protection threshold and a third protection threshold are determined based on the conversion relationship and the first protection threshold, including: determining the second protection threshold based on the difference between the negative of the first protection threshold and the first phase current; and determining the third protection threshold based on the difference between the first protection threshold and the first phase current.

[0017] In this technical solution, based on the equation (third phase current + second phase current + first phase current = 0), the conversion relationship between the third phase current, the second phase current, and the first phase current can be determined. This means the expression for the third phase current with respect to the second and first phase currents is determined: third phase current = -second phase current - first phase current. Furthermore, during overcurrent protection, the third phase current must satisfy the protection condition: the negative of the first protection threshold is less than the third phase current, and the third phase current is less than the first protection threshold. Therefore, based on the above conversion relationship, substituting the expression for the third phase current with respect to the second and first phase currents into the protection condition yields two sets of correspondences between the second and first phase currents and the first protection threshold. Based on this, in this technical solution, the second protection threshold is obtained based on the difference between the negative of the first protection threshold and the first phase current, and the third protection threshold is obtained based on the difference between the first protection threshold and the first phase current. Thus, the third and second protection thresholds change with the sampled value of the first phase current. Based on the determined third and second protection thresholds, overcurrent detection of the second phase current can also achieve overcurrent protection for the third phase current. In this way, overcurrent protection for all three phases can be achieved by sampling only two phase currents, reducing the cost of overcurrent detection, minimizing the delay of overcurrent protection, and improving the accuracy and speed of overcurrent detection.

[0018] In some technical solutions, overcurrent detection can optionally be performed based on the first phase current, the second phase current, the first protection threshold, the second protection threshold, and the third protection threshold, including: determining a first threshold range based on the first protection threshold; determining a second threshold range based on the first protection threshold, the second protection threshold, and the third protection threshold; and performing overcurrent detection based on the comparison result between the first phase current and the first threshold range, and the comparison result between the second phase current and the second threshold range.

[0019] In this technical solution, a first threshold range for overcurrent detection of the first phase current is determined based on the obtained first protection threshold. A second threshold range for overcurrent detection of the second phase current is determined based on the third protection threshold, the second protection threshold, and the first protection threshold. Furthermore, overcurrent detection of all three phase currents is performed based on the comparison results between the first threshold range and the first phase current, and the comparison results between the second threshold range and the second phase current. In this way, overcurrent protection of all three phase currents can be achieved by sampling only two phase currents, reducing the cost of overcurrent detection, decreasing the delay of overcurrent protection, and improving the accuracy and speed of overcurrent detection.

[0020] In some technical solutions, optionally, the range of the second threshold is determined based on the first protection threshold, the second protection threshold, and the third protection threshold, including: determining a lower limit value based on the larger of the opposite of the first protection threshold and the second protection threshold; determining an upper limit value based on the smaller of the first protection threshold and the third protection threshold; and determining the range of the second threshold based on the upper limit value and the lower limit value.

[0021] In this technical solution, the larger of the second protection threshold and the negative of the first protection threshold is determined as the lower limit of the second threshold range, and the smaller of the third protection threshold and the first protection threshold is determined as the upper limit of the second threshold range. The second threshold range is then obtained based on the determined lower and upper limits. Thus, the second threshold range changes with the sampled value of the first phase current. After overcurrent detection of the second phase current based on the determined second threshold range, overcurrent protection for the third phase current can also be achieved. In this way, overcurrent protection for three-phase currents can be achieved by sampling only two phase currents, reducing the cost of overcurrent detection, decreasing the delay of overcurrent protection, and improving the accuracy and speed of overcurrent detection.

[0022] In some technical solutions, optionally, overcurrent detection is performed based on the comparison result of the first phase current and the first threshold range, and the comparison result of the second phase current and the second threshold range, including: stopping the output of pulse signals and issuing an overcurrent alarm when the first phase current exceeds the first threshold range or the second phase current exceeds the second threshold range.

[0023] In this technical solution, if the first-phase current is outside the first threshold range, an abnormality is determined. At this time, the PWM (Pulse Width Modulation) controller stops outputting pulse signals and issues an overcurrent alarm to promptly notify technical personnel to handle the problem. Alternatively, if the second-phase current is outside the second threshold range, an abnormality is determined for either the second or third-phase current. In this case, the PWM controller stops outputting pulse signals and issues an overcurrent alarm to promptly notify technical personnel to handle the problem. Thus, overcurrent protection for three-phase currents can be achieved by sampling only two-phase currents, reducing the cost of overcurrent detection, minimizing the delay of overcurrent protection, and improving the accuracy and speed of overcurrent detection, thereby enhancing the timeliness of overcurrent protection.

[0024] According to a second aspect of the present invention, an overcurrent detection device is provided, the device comprising: an acquisition unit for acquiring a first phase current, a second phase current, and a first protection threshold; a processing unit for determining a conversion relationship between the third phase current and the first and second phase currents based on the vector sum of the first phase current, the second phase current, and the third phase current being zero; the processing unit further for determining a second protection threshold and a third protection threshold according to the conversion relationship and the first protection threshold; and the processing unit further for performing overcurrent detection based on the first phase current, the second phase current, the first protection threshold, the second protection threshold, and the third protection threshold; wherein the conversion relationship is used to indicate the expression of the third phase current with respect to the first and second phase currents.

[0025] The overcurrent detection device provided by this invention is used for overcurrent detection of three-phase current, namely the third phase current, the second phase current and the first phase current, so as to realize overcurrent protection of the three-phase current.

[0026] Specifically, the overcurrent detection device provided by this invention includes an acquisition unit and a processing unit. During the overcurrent protection of three-phase current, the acquisition unit acquires a set three-phase current protection threshold, i.e., a first protection threshold, and samples and detects the second-phase current and the first-phase current to obtain their current sample values. Based on this, the processing unit determines a third protection threshold and a second protection threshold according to the acquired first protection threshold and first-phase current.

[0027] Specifically, the vector sum of the third-phase current, the second-phase current, and the first-phase current is zero, i.e., third-phase current + second-phase current + first-phase current = 0. Based on this, and given that third-phase current + second-phase current + first-phase current = 0, the conversion relationship between the third-phase current and the second and first-phase currents can be determined, i.e., the expression for the third-phase current with respect to the second and first-phase currents is determined: third-phase current = -second-phase current - first-phase current. Furthermore, during overcurrent protection, the third-phase current must satisfy the protection condition: the negative of the first protection threshold is less than the third-phase current, and the third-phase current is less than the first protection threshold. Therefore, based on the above conversion relationship, substituting the expression for the third-phase current with respect to the second and first-phase currents into the above protection condition, two sets of correspondences between the second-phase current, the first-phase current, and the aforementioned first protection threshold can be obtained. Further, based on these two sets of correspondences between the second-phase current, the first-phase current, and the aforementioned first protection threshold, the two corresponding protection thresholds, namely the third protection threshold and the second protection threshold, can be obtained.

[0028] Furthermore, the processing unit performs overcurrent detection on the three-phase current based on the determined third and second protection thresholds, and the acquired first protection threshold, second-phase current, and first-phase current. Specifically, the processing unit performs overcurrent detection on the first-phase current based on the aforementioned first protection threshold, and performs overcurrent detection on the second-phase current based on the determined third and second protection thresholds. The first protection threshold remains constant, while the third and second protection thresholds change with the sampled value of the first-phase current. In other words, the overcurrent detection device provided by this invention maintains the protection threshold of the first-phase current constant during the overcurrent protection process for the three-phase current, and updates the protection threshold of the second-phase current in real time based on the sampled value of the first-phase current. It is understood that the vector sum of the third-phase current, second-phase current, and first-phase current is zero; therefore, the change in the value of the first-phase current is related to the value of the third-phase current. Thus, when performing overcurrent protection on the second-phase current based on the determined third and second protection thresholds, overcurrent protection on the third-phase current can also be achieved. In this way, overcurrent protection for three-phase current can be achieved by sampling only two-phase current, which reduces the cost of overcurrent detection, reduces the delay of overcurrent protection, and improves the accuracy and speed of overcurrent detection.

[0029] According to a third aspect of the present invention, another overcurrent detection device is proposed, comprising: a memory storing a program or instructions; and a processor, which, when executing the program or instructions, implements the steps of the overcurrent detection method as described in any of the above-described technical solutions. Therefore, the overcurrent detection device proposed in the third aspect of the present invention possesses all the beneficial effects of the overcurrent detection method in any of the technical solutions of the first aspect, which will not be elaborated further here.

[0030] According to a fourth aspect of the present invention, a servo driver is provided, comprising: the overcurrent detection device of the third aspect of the technical solution described above. The servo driver proposed in the fourth aspect of the present invention includes the overcurrent detection device of the third aspect of the technical solution described above. Therefore, the servo driver proposed in the fourth aspect of the present invention possesses all the beneficial effects of the overcurrent detection device of the third aspect of the technical solution described above, which will not be elaborated further here.

[0031] According to a fifth aspect of the invention, another servo driver is provided, comprising: a pulse width modulation device for outputting a pulse signal; a processor for determining a second protection threshold and a third protection threshold based on the vector sum of a first phase current, a second phase current, and a third phase current being zero, according to a first protection threshold, a conversion relationship between the third phase current and the first and second phase currents, determining a first threshold range according to the first protection threshold, and determining a second threshold range according to the first protection threshold, the second protection threshold, and the third protection threshold; a first comparator for comparing the first phase current and the first threshold range; a second comparator for comparing the second phase current and the second threshold range; and the processor further for controlling the pulse width modulation device to operate according to the comparison results of the first and second comparators; wherein the conversion relationship is used to indicate the expression of the third phase current with respect to the first and second phase currents.

[0032] Specifically, the servo driver proposed in this invention includes a pulse width modulation device, a processor, a first comparator, and a second comparator.

[0033] The pulse width modulation device is used to output pulse signals.

[0034] Further, the processor acquires the first-phase current, the second-phase current, and a first protection threshold. Based on the fact that the vector sum of the first-phase current, the second-phase current, and the third-phase current is zero, it determines the conversion relationship between the first protection threshold, the third-phase current, and the first and second-phase currents. Based on this conversion relationship and the first protection threshold, it determines the second and third protection thresholds. Furthermore, based on the first protection threshold, it determines the first threshold range, and based on the first, second, and third protection thresholds, it determines the second threshold range. The aforementioned conversion relationship indicates the expression of the third-phase current with respect to the first and second-phase currents.

[0035] Furthermore, the first comparator is used to compare the first phase current with the first threshold range.

[0036] Furthermore, the second comparator is used to compare the second phase current and the second threshold range.

[0037] The first threshold range is determined based on a first protection threshold and is used for overcurrent detection of the first phase current. The second threshold range is determined based on a third protection threshold, the second protection threshold, and the first protection threshold and is used for overcurrent detection of the second phase current. Based on this, during the operation of the servo driver, after comparing the first phase current with the first threshold range using a first comparator to detect overcurrent in the first phase current, and comparing the second phase current with the second threshold range using a second comparator to detect overcurrent in the second phase current, overcurrent detection of the third phase current can be achieved.

[0038] Furthermore, the processor is also used to control the pulse width modulation device to operate based on the comparison results of the first and second comparators. Specifically, when the first phase current exceeds the first threshold range, or when the second phase current exceeds the second threshold range, the processor controls the pulse width modulation device to stop outputting pulse signals and issues an overcurrent alarm to promptly notify technicians to handle the problem. In this way, overcurrent protection for three-phase currents can be achieved by sampling only two-phase currents, reducing the cost of overcurrent detection, decreasing the delay of overcurrent protection, and improving the accuracy and speed of overcurrent detection.

[0039] According to a sixth aspect of the present invention, a readable storage medium is provided on which a program or instructions are stored, which, when executed by a processor, implement the overcurrent detection method as described in any of the above-described technical solutions. Therefore, the readable storage medium proposed in the sixth aspect of the present invention possesses all the beneficial effects of the overcurrent detection method in any of the technical solutions of the first aspect, and will not be elaborated further here.

[0040] Additional aspects and advantages of the invention will become apparent in the following description or may be learned by practice of the invention. Attached Figure Description

[0041] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0042] Figure 1 One of the flowcharts of the overcurrent detection method according to an embodiment of the present invention is shown;

[0043] Figure 2 A second schematic flowchart of the overcurrent detection method according to an embodiment of the present invention is shown;

[0044] Figure 3 The third schematic flowchart of the overcurrent detection method according to an embodiment of the present invention is shown;

[0045] Figure 4 The fourth schematic flowchart of the overcurrent detection method according to an embodiment of the present invention is shown;

[0046] Figure 5 The fifth schematic flowchart of the overcurrent detection method according to an embodiment of the present invention is shown;

[0047] Figure 6 The sixth schematic flowchart of the overcurrent detection method according to an embodiment of the present invention is shown;

[0048] Figure 7 The seventh flowchart of the overcurrent detection method according to an embodiment of the present invention is shown;

[0049] Figure 8One of the structural block diagrams of the overcurrent detection device according to an embodiment of the present invention is shown;

[0050] Figure 9 A second structural block diagram of the overcurrent detection device according to an embodiment of the present invention is shown;

[0051] Figure 10 One of the structural block diagrams of the servo driver according to an embodiment of the present invention is shown;

[0052] Figure 11 A second structural block diagram of the servo driver according to an embodiment of the present invention is shown;

[0053] Figure 12 One of the structural block diagrams of the motor according to an embodiment of the present invention is shown;

[0054] Figure 13 A second structural block diagram of the motor according to an embodiment of the present invention is shown;

[0055] Figure 14 This invention illustrates one of the structural block diagrams of an electrical device according to an embodiment of the present invention;

[0056] Figure 15 A second structural block diagram of an electrical device according to an embodiment of the present invention is shown;

[0057] Figure 16 A principle block diagram of the overcurrent detection method according to an embodiment of the present invention is shown. Detailed Implementation

[0058] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0059] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0060] The following is combined with Figures 1 to 16 The overcurrent detection method and device, servo driver and readable storage medium provided in this application will be described in detail through specific embodiments and application scenarios.

[0061] In one embodiment of the present invention, such as Figure 1 As shown, the overcurrent detection method may specifically include the following steps 102 to 108:

[0062] Step 102: Obtain the first phase current, the second phase current, and the first protection threshold.

[0063] Step 104: Based on the fact that the vector sum of the first phase current, the second phase current, and the third phase current is zero, determine the conversion relationship between the third phase current and the first and second phase currents;

[0064] Step 106: Determine the second protection threshold and the third protection threshold based on the conversion relationship and the first protection threshold;

[0065] Step 108: Perform overcurrent detection based on the first phase current, the second phase current, the first protection threshold, the second protection threshold, and the third protection threshold;

[0066] The conversion relationship is used to indicate the expression of the third phase current with respect to the first phase current and the second phase current.

[0067] The overcurrent detection method provided by this invention is used to detect overcurrent of three-phase current, namely the third phase current, the second phase current and the first phase current, so as to realize overcurrent protection of three-phase current.

[0068] Specifically, in the overcurrent detection method provided by this invention, during the overcurrent protection of three-phase current, a set three-phase current protection threshold, namely the first protection threshold, is obtained, and the second-phase current and the first-phase current are sampled and detected to obtain the current sample values ​​of the second-phase current and the first-phase current. Based on this, a third protection threshold and a second protection threshold are determined according to the obtained first protection threshold and first-phase current.

[0069] Specifically, the vector sum of the third-phase current, the second-phase current, and the first-phase current is zero, i.e., third-phase current + second-phase current + first-phase current = 0. Based on this, and given that third-phase current + second-phase current + first-phase current = 0, the conversion relationship between the third-phase current and the second and first-phase currents can be determined, i.e., the expression for the third-phase current with respect to the second and first-phase currents is determined: third-phase current = -second-phase current - first-phase current. Furthermore, during overcurrent protection, the third-phase current must satisfy the protection condition: the negative of the first protection threshold is less than the third-phase current, and the third-phase current is less than the first protection threshold. Therefore, based on the above conversion relationship, substituting the expression for the third-phase current with respect to the second and first-phase currents into the above protection condition, two sets of correspondences between the second-phase current, the first-phase current, and the aforementioned first protection threshold can be obtained. Further, based on these two sets of correspondences between the second-phase current, the first-phase current, and the aforementioned first protection threshold, the two corresponding protection thresholds, namely the third protection threshold and the second protection threshold, can be obtained.

[0070] Furthermore, based on the determined third and second protection thresholds, and the obtained first protection threshold, second phase current, and first phase current, overcurrent detection is performed on the three-phase current. Specifically, overcurrent detection is performed on the first phase current based on the aforementioned first protection threshold, and overcurrent detection is performed on the second phase current based on the determined third and second protection thresholds. The first protection threshold remains constant, while the third and second protection thresholds change with the sampled value of the first phase current. In other words, in the overcurrent detection method provided by this invention, during the overcurrent protection of the three-phase current, the protection threshold for the first phase current remains constant, and the protection threshold for the second phase current is updated in real time based on the sampled value of the first phase current. It can be understood that the vector sum of the third phase current, the second phase current, and the first phase current is zero; therefore, the change in the value of the first phase current is related to the value of the third phase current. Thus, when overcurrent protection is performed on the second phase current based on the determined third and second protection thresholds, overcurrent protection of the third phase current can also be achieved. In this way, overcurrent protection for three-phase current can be achieved by sampling only two-phase current, which reduces the cost of overcurrent detection, reduces the delay of overcurrent protection, and improves the accuracy and speed of overcurrent detection.

[0071] The first protection threshold is a set three-phase current protection threshold, which can be a positive number. Based on this, during the overcurrent protection of the three-phase current, all three phase currents should meet the following protection conditions: the negative value of the first protection threshold is less than the first phase current, and the first phase current is less than the first protection threshold; the negative value of the first protection threshold is less than the second phase current, and the second phase current is less than the first protection threshold; the negative value of the first protection threshold is less than the third phase current, and the third phase current is less than the first protection threshold.

[0072] Based on this, after performing overcurrent detection on the first phase current based on the first protection threshold, and updating the third and second protection thresholds in real time according to the first protection threshold and the first phase current obtained by real-time sampling, and then performing overcurrent detection on the second phase current based on the obtained third and second protection thresholds, overcurrent protection of the three-phase current can be achieved based on the above protection conditions, without having to perform overcurrent protection after calculating the third phase current in the interrupt service function of the MCU (Micro Control Unit), thus reducing the delay of overcurrent protection and improving the accuracy and speed of overcurrent detection.

[0073] In some embodiments of the present invention, optionally, such as Figure 2 As shown, step 106 above may specifically include steps 106a and 106b as follows:

[0074] Step 106a: Determine the second protection threshold based on the difference between the negative of the first protection threshold and the first phase current;

[0075] Step 106b: Determine the third protection threshold based on the difference between the first protection threshold and the first phase current.

[0076] It is understandable that, based on the equation "third phase current + second phase current + first phase current = 0", the conversion relationship between the third phase current and the second and first phase currents can be determined, that is, the expression for the third phase current in terms of the second and first phase currents can be determined: third phase current = -second phase current - first phase current. Furthermore, during overcurrent protection, the third phase current should satisfy the protection condition: the negative of the first protection threshold is less than the third phase current, and the third phase current is less than the first protection threshold. Therefore, based on the above conversion relationship, substituting the expression for the third phase current in terms of the second and first phase currents into the above protection condition, two sets of correspondences between the second and first phase currents and the aforementioned first protection threshold can be obtained.

[0077] Based on this, in this embodiment, during the process of determining the third and second protection thresholds according to the conversion relationship between the third-phase current, the first-phase current, and the second-phase current, and the first-phase current obtained through real-time sampling, specifically, the second protection threshold is obtained based on the difference between the negative of the first protection threshold and the first-phase current, and the third protection threshold is obtained based on the difference between the first protection threshold and the first-phase current. Thus, the third and second protection thresholds change with the sampled value of the first-phase current. After overcurrent detection of the second-phase current based on the determined third and second protection thresholds, overcurrent protection for the third-phase current can also be achieved. In this way, overcurrent protection for three-phase currents can be achieved by sampling only two-phase currents, reducing the cost of overcurrent detection, decreasing the delay of overcurrent protection, and improving the accuracy and speed of overcurrent detection.

[0078] Among them, the second protection threshold is less than the second phase current, and the second phase current is less than the third protection threshold.

[0079] Specifically, based on the equation (third phase current + second phase current + first phase current = 0), the conversion relationship between the third phase current, the second phase current, and the first phase current can be determined, i.e., the expression for the third phase current with respect to the second and first phase currents can be determined: third phase current = -second phase current - first phase current. Further, during overcurrent protection, the third phase current should satisfy the protection condition: the negative of the first protection threshold is less than the third phase current, and the third phase current is less than the first protection threshold. Based on this, and substituting the expression for the third phase current with respect to the second and first phase currents into the above-mentioned condition, two sets of correspondences between the second and first phase currents and the first protection threshold can be obtained: (-second phase current - first phase current) < first protection threshold, (-second phase current - first phase current) > (-first protection threshold). Further, based on these two sets of correspondences, further calculations yield the following relationship: (-first phase current - first protection threshold) < second phase current, (first protection threshold - first phase current) > second phase current. Based on this, the second protection threshold can be obtained as (-first phase current - first protection threshold), and the third protection threshold as (first protection threshold - first phase current). Therefore, the second protection threshold is the difference between the negative of the first phase current and the first protection threshold, and the third protection threshold is the sum of the negative of the first phase current and the first protection threshold. In other words, the second protection threshold is the difference between the negative of the first protection threshold and the first phase current, and the third protection threshold is the difference between the first protection threshold and the first phase current. Here, "-" represents a minus sign or a negative sign.

[0080] In some embodiments of the present invention, optionally, such as Figure 3 As shown, step 108 above may specifically include steps 108a to 108c as follows:

[0081] Step 108a: Determine the range of the first threshold based on the first protection threshold;

[0082] Step 108b: Determine the range of the second threshold based on the third protection threshold, the second protection threshold, and the first protection threshold;

[0083] Step 108c: Perform overcurrent detection based on the comparison results of the first threshold range and the first phase current, and the comparison results of the second threshold range and the second phase current.

[0084] In this embodiment, during the overcurrent detection of three-phase current based on the determined third and second protection thresholds, and the obtained first protection threshold, second-phase current, and first-phase current, specifically, a first threshold range for overcurrent detection of the first-phase current is determined based on the obtained first protection threshold, and a second threshold range for overcurrent detection of the second-phase current is determined based on the third, second, and first protection thresholds. Furthermore, overcurrent detection of the three-phase current is performed based on the comparison results of the first threshold range and the first-phase current, and the comparison results of the second threshold range and the second-phase current. In this way, overcurrent protection of three-phase current can be achieved by sampling only two-phase currents, reducing the cost of overcurrent detection, decreasing the delay of overcurrent protection, and improving the accuracy and speed of overcurrent detection.

[0085] In the process of overcurrent protection for three-phase current, the first phase current should meet the following protection conditions: the negative of the first protection threshold is less than the first phase current, and the first phase current is less than the first protection threshold. Based on this, the range of the first threshold can be obtained as: (-first protection threshold, first protection threshold), that is, (-first protection threshold) < first phase current < first protection threshold.

[0086] Furthermore, during the overcurrent protection of three-phase current, the second-phase current should meet the following protection conditions: the negative of the first protection threshold is less than the second-phase current, and the second-phase current is less than the first protection threshold.

[0087] Furthermore, the second phase current should also satisfy the following conditions: the second protection threshold < the second phase current, and the second phase current < the third protection threshold.

[0088] Based on this, the range of the second threshold can be obtained as: (-first protection threshold, first protection threshold) ∩ (second protection threshold, third protection threshold), that is, (-first protection threshold) < second phase current < first protection threshold, and second protection threshold < second phase current < third protection threshold.

[0089] In some embodiments of the present invention, optionally, such as Figure 4 As shown, step 108b above may specifically include steps 108b1 to 108b3 as follows:

[0090] Step 108b1: Determine the lower limit value based on the larger of the second protection threshold and the opposite of the first protection threshold;

[0091] Step 108b2: Determine the upper limit value based on the smaller value between the third protection threshold and the first protection threshold;

[0092] Step 108b3: Determine the range of the second threshold based on the lower limit and the upper limit.

[0093] In this embodiment, in the process of determining the second threshold range for performing overcurrent detection on the second phase current according to the third protection threshold, the second protection threshold and the first protection threshold, specifically, the larger value of the second protection threshold and the opposite number of the first protection threshold is determined as the lower limit value of the second threshold range, and the smaller value of the third protection threshold and the first protection threshold is determined as the upper limit value of the second threshold range, and then the above-mentioned second threshold range is obtained according to the determined lower limit value and upper limit value. In this way, the second threshold range changes with the sampled current value of the first phase current, and after the overcurrent detection is performed on the second phase current based on the determined second threshold range, the overcurrent protection for the third phase current can also be realized. In this way, the overcurrent protection for three-phase currents can be realized only by sampling two-phase currents, which reduces the cost of overcurrent detection, shortens the delay of overcurrent protection, and improves the accuracy and speed of overcurrent detection.

[0094] It can be understood that in the process of performing overcurrent protection on the three-phase currents, the second phase current should meet the following protection condition: the opposite number of the first protection threshold is less than the second phase current, and the second phase current is less than the first protection threshold.

[0095] Further, the second phase current should also satisfy: the second protection threshold < the second phase current, and the second phase current < the third protection threshold.

[0096] Based on this, the above-mentioned second threshold range can be obtained as: (-first protection threshold, first protection threshold) ∩ (second protection threshold, third protection threshold), that is, (-first protection threshold) < the second phase current < the first protection threshold, and the second protection threshold < the second phase current < the third protection threshold. In this way, to ensure that the overcurrent protection for the third phase current can also be realized when performing overcurrent protection on the second phase current, the second phase current needs to meet the following protection condition: the second phase current > max(-first protection threshold, second protection threshold), and the second phase current < min(first protection threshold, third protection threshold). That is, the above-mentioned second threshold range is: {max(-first protection threshold, second protection threshold), min(first protection threshold, third protection threshold)}.

[0097] In some embodiments of the present invention, optionally, as Figure 5 shown, the above step 108c may specifically include the following step 108c1:

[0098] Step 108c1, in the case where the first phase current is outside the first threshold range, or the second phase current is outside the second threshold range, stop outputting the pulse signal, and issue an overcurrent alarm.

[0099] In this embodiment, during the overcurrent detection of the three-phase current based on the comparison results of the first threshold range and the first phase current, and the comparison results of the second threshold range and the second phase current, specifically, if the first phase current is outside the first threshold range (i.e., if the sampled first phase current is less than or equal to the negative of the first protection threshold, or if the sampled first phase current is greater than or equal to the first protection threshold), the first phase current is determined to be abnormal. In this case, the PWM controller stops outputting pulse signals and issues an overcurrent alarm to promptly notify technical personnel to handle the problem. Alternatively, if the second phase current is outside the second threshold range (i.e., if the sampled second phase current is less than or equal to the larger of the second protection threshold and the negative of the first protection threshold, or if the sampled second phase current is greater than or equal to the smaller of the third protection threshold and the first protection threshold), the second or third phase current is determined to be abnormal. In this case, the PWM controller stops outputting pulse signals and issues an overcurrent alarm to promptly notify technical personnel to handle the problem. In this way, overcurrent protection for three-phase current can be achieved by sampling only two-phase current, which reduces the cost of overcurrent detection, reduces the delay of overcurrent protection, and improves the accuracy and speed of overcurrent detection, thereby improving the timeliness of overcurrent protection.

[0100] In summary, the overcurrent detection method proposed in the embodiments of the present invention, such as Figure 16 As shown, the Σ-Δ comparator of the MCU is used to measure only two-phase currents, such as phase B current I. B and C-phase current I C In the case of sampling, fast and high-precision three-phase overcurrent protection is provided. Specifically, this invention updates the sampled B-phase current I in the MCU interrupt service function. B and C-phase current I C The overcurrent protection threshold of one phase, and the B-phase current I that is being sampled. B and C-phase current I C The overcurrent protection threshold of the other phase remains unchanged to achieve overcurrent detection and protection of the three-phase current, and in the B-phase current I B Or the C-phase current I C If the corresponding protection threshold is exceeded, the PWM output is blocked. For example, this can be achieved by updating the B-phase current I in real time within the MCU interrupt service function. B Overcurrent protection threshold I TB And maintain the C-phase current I C Overcurrent protection threshold I TC This remains unchanged, thus enabling overcurrent detection and protection of the three-phase current.

[0101] The delay of a Σ-Δ comparator is significantly smaller than that of an MCU interrupt. For example, a Σ-Δ comparator with a 32 decimation rate and 20 MHz has a delay of 2.4 microseconds, while the interrupt cycle of an MCU is tens to hundreds of microseconds. Therefore, this application uses a Σ-Δ comparator for overcurrent protection, which improves the accuracy and speed of overcurrent detection, thereby enhancing the timeliness of overcurrent protection, reducing the probability of driver damage, and enabling three-phase current overcurrent detection and protection through two-phase current sampling without increasing costs.

[0102] For example, in the case where the first phase current is phase B, the second phase current is phase C, and the third phase current is phase A, such as Figure 6 As shown, the above-mentioned overcurrent detection method may specifically include the following steps 202 to 214:

[0103] Step 202, obtain the three-phase current protection threshold I. t ;

[0104] Step 204: Obtain the current detection values ​​I for phase B and phase C. B I C ;

[0105] Step 206, calculate the C-phase current protection threshold: I C <min(I t I t -I B ), and I C >max(-I t -I t -I B );

[0106] Step 208, set the upper threshold of phase B current to I. t The lower threshold is -I t ;

[0107] Step 210, set the upper threshold of the C-phase current to min(I t I t -I B The lower threshold is max(-I). t -I t -I B );

[0108] Step 212: Determine whether the current of phase B or phase C exceeds the corresponding threshold. If yes, proceed to step 214; otherwise, proceed to step 204.

[0109] Step 214: Disable PWM and trigger an overcurrent alarm.

[0110] Specifically, in the overcurrent detection method proposed in this embodiment of the invention, during the overcurrent detection of the three-phase current, a set protection threshold I for the three-phase current is obtained. t Then, the current of phase B and phase C is sampled and detected to obtain the current detection values ​​I of phase B and phase C. B I C Furthermore, based on the A-phase current I... A Phase B current I B and C-phase current I C The principle that the vector sum of is 0, that is, based on I A +I B +I C =0, then I can be obtained A =-I B -I C Based on this, due to I A t , and I A >-I t We can obtain -I B -I C t and -I B -I C >-I t Therefore, we can obtain I C t -I B and I C >-I t -I B Based on this, because I C t , and I C >-I t The C-phase current I can then be calculated. C The protection threshold is: I C <min(I t I t -I B ), and I C >max(-I t -I t -I B Based on this, the B-phase current I is set. B The upper threshold is I t The lower threshold is -I t And setting the C-phase current I C The upper threshold is min(I) t I t -I B The lower threshold is max(-I). t -I t -I B ​​​​Furthermore, the sampled B-phase current I... B and C-phase current I C The current I in phase B is compared with the set threshold. B Or the C-phase current I C If the corresponding threshold is exceeded, PWM is disabled and an overcurrent alarm is triggered to provide overcurrent protection for the three-phase current, while the B-phase current I... B and C-phase current I C If all currents are within their corresponding thresholds, sampling of phase B and phase C currents continues to begin the next round of overcurrent detection. Thus, during the three-phase overcurrent detection process, based on the principle that the vector sum of phase A, phase B, and phase C currents is zero, the threshold for phase C current is updated in real time with the sampled value of phase B current. This allows for overcurrent protection of phase A current while simultaneously protecting phase C current. In this way, overcurrent protection of all three phases can be achieved by sampling only two phases of current, reducing the cost of overcurrent detection, minimizing overcurrent protection delay, and improving the accuracy and speed of overcurrent detection.

[0111] For example, in the case where the first phase current is phase C, the second phase current is phase B, and the third phase current is phase A, such as... Figure 7 As shown, the above overcurrent detection method may specifically include the following steps 302 to 314:

[0112] Step 302, obtain the three-phase current protection threshold I. t ;

[0113] Step 304: Obtain the current detection values ​​I for phase B and phase C. B I C ;

[0114] Step 306, calculate the B-phase current protection threshold: I B <min(I t I t -I C ), and I B >max(-I t -I t -I C );

[0115] Step 308, set the upper threshold of the C-phase current to I. t The lower threshold is -I t ;

[0116] Step 310, set the upper threshold of phase B current to min(I t I t -I C The lower threshold is max(-I).t -I t -I C );

[0117] Step 312: Determine whether the current of phase B or phase C exceeds the corresponding threshold. If yes, proceed to step 314; otherwise, proceed to step 304.

[0118] Step 314: Disable PWM and trigger an overcurrent alarm.

[0119] Specifically, in the overcurrent detection method proposed in this embodiment of the invention, during the overcurrent detection of the three-phase current, a set protection threshold I for the three-phase current is obtained. t Then, the current of phase B and phase C is sampled and detected to obtain the current detection values ​​I of phase B and phase C. B I C Furthermore, based on the A-phase current I... A Phase B current I B and C-phase current I C The principle that the vector sum of is 0, that is, based on I A +I B +I C =0, then I can be obtained A =-I B -I C Based on this, due to I A t , and I A >-I t We can obtain -I B -I C t and -I B -I C >-I t Therefore, we can obtain I B t -I C and I B >-I t -I C Based on this, because I B t , and I B >-I t The phase B current I can then be calculated. B The protection threshold is: I B <min(I t I t -I C ), and I B >max(-I t -I t -I C Based on this, the C-phase current I is set.​​​​C The upper threshold is I t The lower threshold is -I t And setting the B-phase current I B The upper threshold is min(I) t I t -I C The lower threshold is max(-I). t -I t -I C Furthermore, the sampled B-phase current I... B and C-phase current I C The current I in phase B is compared with the set threshold. B Or the C-phase current I C If the corresponding threshold is exceeded, PWM is disabled and an overcurrent alarm is triggered to provide overcurrent protection for the three-phase current, while the B-phase current I... B and C-phase current I C If all currents are within their corresponding thresholds, sampling of phase B and phase C currents continues to begin the next round of overcurrent detection. Thus, during the three-phase overcurrent detection process, based on the principle that the vector sum of phase A, phase B, and phase C currents is zero, the threshold for phase C current is updated in real time with the sampled value of phase B current. This allows for overcurrent protection of phase A current while simultaneously protecting phase C current. In this way, overcurrent protection of all three phases can be achieved by sampling only two phases of current, reducing the cost of overcurrent detection, minimizing overcurrent protection delay, and improving the accuracy and speed of overcurrent detection.

[0120] In one embodiment of the present invention, an overcurrent detection device is also provided. For example... Figure 8 As shown, Figure 8 A structural block diagram of an overcurrent detection device 800 according to an embodiment of the present invention is shown. Specifically, the overcurrent detection device 800 may include an acquisition unit 802 and a processing unit 804.

[0121] The acquisition unit 802 is used to acquire the first protection threshold, the second phase current, and the first phase current;

[0122] Processing unit 804 is used to determine the conversion relationship between the third phase current and the first and second phase currents based on the fact that the vector sum of the first phase current, the second phase current and the third phase current is zero.

[0123] The processing unit 804 is also configured to determine the second protection threshold and the third protection threshold based on the conversion relationship and the first protection threshold;

[0124] The processing unit 804 is also used to perform overcurrent detection based on the third protection threshold, the second protection threshold, the first protection threshold, the second phase current, and the first phase current;

[0125] The conversion relationship is used to indicate the expression of the third phase current with respect to the first phase current and the second phase current.

[0126] The overcurrent detection device 800 provided in this embodiment of the invention is used for overcurrent detection of three-phase current, namely the third phase current, the second phase current and the first phase current, so as to realize overcurrent protection of the three-phase current.

[0127] Specifically, the overcurrent detection device 800 provided by the present invention includes an acquisition unit 802 and a processing unit 804. During the overcurrent protection of three-phase current, the acquisition unit 802 acquires a set three-phase current protection threshold, i.e., a first protection threshold, and samples and detects the second-phase current and the first-phase current to obtain their current sampling values. Based on this, the processing unit 804 determines a third protection threshold and a second protection threshold according to the acquired first protection threshold and first-phase current.

[0128] Specifically, the vector sum of the third-phase current, the second-phase current, and the first-phase current is zero, i.e., third-phase current + second-phase current + first-phase current = 0. Based on this, and given that third-phase current + second-phase current + first-phase current = 0, the conversion relationship between the third-phase current and the second and first-phase currents can be determined, i.e., the expression for the third-phase current with respect to the second and first-phase currents is determined: third-phase current = -second-phase current - first-phase current. Furthermore, during overcurrent protection, the third-phase current must satisfy the protection condition: the negative of the first protection threshold is less than the third-phase current, and the third-phase current is less than the first protection threshold. Therefore, based on the above conversion relationship, substituting the expression for the third-phase current with respect to the second and first-phase currents into the above protection condition, two sets of correspondences between the second-phase current, the first-phase current, and the aforementioned first protection threshold can be obtained. Further, based on these two sets of correspondences between the second-phase current, the first-phase current, and the aforementioned first protection threshold, the two corresponding protection thresholds, namely the third protection threshold and the second protection threshold, can be obtained.

[0129] Further, the processing unit 804 performs overcurrent detection on the three-phase current based on the determined third protection threshold and second protection threshold, as well as the acquired first protection threshold, second phase current, and first phase current. Specifically, the processing unit 804 performs overcurrent detection on the first phase current based on the aforementioned first protection threshold, and performs overcurrent detection on the second phase current based on the determined third protection threshold and second protection threshold. The first protection threshold remains constant, while the third and second protection thresholds change with the sampled value of the first phase current. In other words, the overcurrent detection device 800 provided by this invention maintains the protection threshold of the first phase current constant during the overcurrent protection process of the three-phase current, and updates the protection threshold of the second phase current in real time based on the sampled value of the first phase current. It can be understood that the vector sum of the third phase current, second phase current, and first phase current is zero; therefore, the change in the value of the first phase current is related to the value of the third phase current. Thus, when overcurrent protection of the second-phase current is performed based on the determined third and second protection thresholds, overcurrent protection of the third-phase current can also be achieved. In this way, overcurrent protection of all three-phase currents can be achieved by sampling only two-phase currents, reducing the cost of overcurrent detection, decreasing the delay of overcurrent protection, and improving the accuracy and speed of overcurrent detection.

[0130] The first protection threshold is a set three-phase current protection threshold, which can be a positive number. Based on this, during the overcurrent protection of the three-phase current, all three phase currents should meet the following protection conditions: the negative value of the first protection threshold is less than the first phase current, and the first phase current is less than the first protection threshold; the negative value of the first protection threshold is less than the second phase current, and the second phase current is less than the first protection threshold; the negative value of the first protection threshold is less than the third phase current, and the third phase current is less than the first protection threshold.

[0131] Based on this, after the processing unit 804 performs overcurrent detection on the first phase current based on the first protection threshold, and updates the third and second protection thresholds in real time according to the first protection threshold and the first phase current obtained by real-time sampling, and performs overcurrent detection on the second phase current based on the obtained third and second protection thresholds, overcurrent protection of the three-phase current can be realized based on the above protection conditions, without having to perform overcurrent protection after the third phase current is calculated in the interrupt service function of the MCU, thus reducing the delay of overcurrent protection and improving the accuracy and speed of overcurrent detection.

[0132] In some embodiments of the present invention, optionally, the processing unit 804 is specifically configured to: determine a second protection threshold based on the difference between the opposite of the first protection threshold and the first phase current; and determine a third protection threshold based on the difference between the first protection threshold and the first phase current.

[0133] In some embodiments of the present invention, optionally, the processing unit 804 is specifically used to: determine a first threshold range based on a first protection threshold; determine a second threshold range based on a third protection threshold, a second protection threshold, and the first protection threshold; and perform overcurrent detection based on the comparison result between the first threshold range and the first phase current, and the comparison result between the second threshold range and the second phase current.

[0134] In some embodiments of the present invention, optionally, the processing unit 804 is specifically configured to: determine a lower limit value based on the larger of a second protection threshold and the opposite of a first protection threshold; determine an upper limit value based on the smaller of a third protection threshold and a first protection threshold; and determine a second threshold range based on the lower limit value and the upper limit value.

[0135] In some embodiments of the present invention, optionally, the processing unit 804 is specifically configured to: stop outputting pulse signals and issue an overcurrent alarm when the first phase current is outside the first threshold range or the second phase current is outside the second threshold range.

[0136] In one embodiment of the present invention, another overcurrent detection device is also proposed. For example... Figure 9 As shown, Figure 9 A structural block diagram of an overcurrent detection device 900 provided in an embodiment of the present invention is shown. The overcurrent detection device 900 includes:

[0137] Memory 902, which stores programs or instructions;

[0138] The processor 904, when executing the above program or instructions, implements the steps of the overcurrent detection method as described in any of the above embodiments.

[0139] The overcurrent detection device 900 provided in this embodiment includes a memory 902 and a processor 904. When the program or instructions in the memory 902 are executed by the processor 904, they implement the steps of the overcurrent detection method as described in any of the above embodiments. Therefore, the overcurrent detection device 900 has all the beneficial effects of the overcurrent detection method in any of the above embodiments, which will not be repeated here.

[0140] Specifically, the memory 902 and the processor 904 can be connected via a bus or other means. The processor 904 may include one or more processing units, and the processor 904 may be a central processing unit (CPU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other chips.

[0141] In one embodiment of the present invention, a servo driver is also provided. For example... Figure 10 As shown, Figure 10 A structural block diagram of a servo driver 1000 provided in an embodiment of the present invention is shown. The servo driver 1000 includes the overcurrent detection device 900 described in the third aspect embodiment above. The servo driver 1000 proposed in the fourth aspect embodiment of the present invention includes the overcurrent detection device 900 described in the third aspect embodiment above. Therefore, the servo driver 1000 proposed in the fourth aspect embodiment of the present invention possesses all the beneficial effects of the overcurrent detection device 900 described in the third aspect embodiment above, which will not be repeated here.

[0142] In one embodiment of the invention, alternatively, another servo driver is also proposed. For example... Figure 11 As shown, the servo driver 1100 includes a pulse width modulation device 1102, a processor 1104, a first comparator 1106, and a second comparator 1108.

[0143] Among them, the pulse width modulation device 1102, also known as the PWM device, is used to output pulse signals.

[0144] Further, the processor 1104 is used to acquire the first phase current, the second phase current, and the first protection threshold. Based on the fact that the vector sum of the first phase current, the second phase current, and the third phase current is zero, it determines the conversion relationship between the first protection threshold, the third phase current, and the first and second phase currents. Based on this conversion relationship and the first protection threshold, it determines the second and third protection thresholds. Furthermore, based on the first protection threshold, it determines the first threshold range, and based on the first, second, and third protection thresholds, it determines the second threshold range. The aforementioned conversion relationship is used to indicate the expression of the third phase current with respect to the first and second phase currents.

[0145] Furthermore, the first comparator 1106 is used to compare the first phase current with the first threshold range.

[0146] Furthermore, the second comparator 1108 is used to compare the second phase current and the second threshold range.

[0147] The first threshold range is determined based on a first protection threshold and is used for overcurrent detection of the first phase current. The second threshold range is determined based on a third protection threshold, the second protection threshold, and the first protection threshold and is used for overcurrent detection of the second phase current. Based on this, during the operation of the servo driver 1100, after comparing the first phase current and the first threshold range using the first comparator 1106 to perform overcurrent detection of the first phase current, and comparing the second phase current and the second threshold range using the second comparator 1108 to perform overcurrent detection of the second phase current, overcurrent detection of the third phase current can be achieved.

[0148] Furthermore, the processor 1104 is also used to control the pulse width modulation device 1102 to operate based on the comparison results of the first comparator 1106 and the second comparator 1108. Specifically, when the first phase current exceeds the first threshold range, or when the second phase current exceeds the second threshold range, the processor 1104 controls the pulse width modulation device 1102 to stop outputting pulse signals and issue an overcurrent alarm to promptly notify technicians to handle the problem. In this way, overcurrent protection for three-phase currents can be achieved by sampling only two-phase currents, reducing the cost of overcurrent detection, decreasing the delay of overcurrent protection, and improving the accuracy and speed of overcurrent detection.

[0149] In addition, in practical applications, the first comparator 1106 and the second comparator 1108 mentioned above can be Σ-Δ comparators, without any specific restrictions.

[0150] In one embodiment of the invention, a motor is also provided. For example... Figure 12 As shown, Figure 12 A structural block diagram of a motor 1200 provided in an embodiment of the present invention is shown. The motor 1200 includes the servo driver 1000 described in the fourth aspect embodiment above. The motor 1200 proposed in this embodiment of the present invention includes the servo driver 1000 described in the fourth aspect embodiment above. Therefore, the motor 1200 proposed in this embodiment of the present invention possesses all the beneficial effects of the servo driver 1000 described in the fourth aspect embodiment above, which will not be elaborated further here.

[0151] In one embodiment of the invention, another type of motor is also proposed. For example... Figure 13 As shown, Figure 13A structural block diagram of a motor 1300 provided in an embodiment of the present invention is shown. The motor 1300 includes the servo driver 1100 described in the fifth aspect embodiment above. The motor 1300 proposed in this embodiment of the present invention includes the servo driver 1100 described in the fifth aspect embodiment above. Therefore, the motor 1300 proposed in this embodiment of the present invention possesses all the beneficial effects of the servo driver 1100 described in the fifth aspect embodiment above, which will not be repeated here.

[0152] In one embodiment of the present invention, an electrical device is also provided. For example... Figure 14 As shown, Figure 14 A structural block diagram of an electrical device 1400 provided in an embodiment of the present invention is shown. The electrical device 1400 includes the motor 1200 in the above embodiments. Therefore, the electrical device 1400 possesses all the technical effects of the motor 1200 in the above embodiments, and will not be described again here.

[0153] In one embodiment of the invention, another electrical device is also proposed. For example... Figure 15 As shown, Figure 15 A structural block diagram of an electrical device 1500 provided in an embodiment of the present invention is shown. The electrical device 1500 includes the motor 1300 in the above embodiments. Therefore, the electrical device 1500 possesses all the technical effects of the motor 1300 in the above embodiments, and will not be repeated here.

[0154] It should be noted that the electrical equipment 1400 and electrical equipment 1500 proposed in the embodiments of the present invention include, but are not limited to, the following products: electric fan, refrigerator, and washing machine, which will not be listed here.

[0155] In one embodiment of the present invention, a readable storage medium is also provided. A program or instructions are stored thereon, which, when executed by a processor, implement the steps of the overcurrent detection method as described in any of the above embodiments.

[0156] The readable storage medium provided in this embodiment of the invention, when the program or instructions stored therein are executed by a processor, can implement the steps of the overcurrent detection method as described in any of the above embodiments. Therefore, this readable storage medium possesses all the beneficial effects of the overcurrent detection method in any of the above embodiments, which will not be elaborated further here.

[0157] Specifically, the aforementioned readable storage medium can include any medium capable of storing or transmitting information. Examples of readable storage media include electronic circuits, semiconductor memory devices, read-only memory (ROM), random access memory (RAM), compact disc read-only memory (CD-ROM), flash memory, erasable ROM (EROM), magnetic tape, floppy disk, optical disk, hard disk, fiber optic media, radio frequency (RF) links, optical data storage devices, etc. Code segments can be downloaded via computer networks such as the Internet and intranets.

[0158] In the description of this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance, unless otherwise expressly specified and limited. The terms "connection," "installation," and "fixing," etc., should be interpreted broadly. For example, "connection" can mean a fixed connection, a detachable connection, or an integral connection; it can mean a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0159] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0160] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0161] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An overcurrent detection method, characterized in that, include: Obtain the first phase current, the second phase current, and the first protection threshold; Based on the fact that the vector sum of the first phase current, the second phase current, and the third phase current is zero, the conversion relationship between the third phase current and the first phase current and the second phase current is determined; Based on the conversion relationship and the first protection threshold, the second protection threshold and the third protection threshold are determined; Overcurrent detection is performed based on the first phase current, the second phase current, the first protection threshold, the second protection threshold, and the third protection threshold. The conversion relationship is used to indicate the expression of the third phase current with respect to the first phase current and the second phase current; The step of determining the second protection threshold and the third protection threshold based on the conversion relationship and the first protection threshold includes: The second protection threshold is determined based on the negative of the first protection threshold and the difference between the first phase current; The third protection threshold is determined based on the difference between the first protection threshold and the first phase current; The overcurrent detection based on the first phase current, the second phase current, the first protection threshold, the second protection threshold, and the third protection threshold includes: Based on the first protection threshold, determine the range of the first threshold; The second threshold range is determined based on the first protection threshold, the second protection threshold, and the third protection threshold; Overcurrent detection is performed based on the comparison results of the first phase current and the first threshold range, and the comparison results of the second phase current and the second threshold range. Determining the second threshold range based on the first protection threshold, the second protection threshold, and the third protection threshold includes: The lower limit value is determined based on the larger of the opposite of the first protection threshold and the second protection threshold; The upper limit value is determined based on the smaller value between the first protection threshold and the third protection threshold; The second threshold range is determined based on the upper limit and the lower limit.

2. The overcurrent detection method according to claim 1, characterized in that, The overcurrent detection based on the comparison result of the first phase current and the first threshold range, and the comparison result of the second phase current and the second threshold range, includes: If the first phase current exceeds the first threshold range, or the second phase current exceeds the second threshold range, the output pulse signal will be stopped and an overcurrent alarm will be triggered.

3. An overcurrent detection device, characterized in that, include: The acquisition unit is used to acquire the first phase current, the second phase current, and the first protection threshold. The processing unit is configured to determine the conversion relationship between the third phase current and the first phase current and the second phase current based on the fact that the vector sum of the first phase current, the second phase current and the third phase current is zero; The processing unit is further configured to determine a second protection threshold and a third protection threshold based on the conversion relationship and the first protection threshold; The processing unit is further configured to perform overcurrent detection based on the first phase current, the second phase current, the first protection threshold, the second protection threshold, and the third protection threshold; The conversion relationship is used to indicate the expression of the third phase current with respect to the first phase current and the second phase current; The processing unit is specifically configured to determine the second protection threshold based on the negative of the first protection threshold and the difference between the first phase current; and to determine the third protection threshold based on the difference between the first protection threshold and the first phase current. The processing unit is specifically used to determine the first threshold range based on the first protection threshold. The second threshold range is determined based on the first protection threshold, the second protection threshold, and the third protection threshold; Overcurrent detection is performed based on the comparison results of the first phase current and the first threshold range, and the comparison results of the second phase current and the second threshold range. The lower limit value is determined based on the larger of the opposite of the first protection threshold and the second protection threshold; The upper limit value is determined based on the smaller value between the first protection threshold and the third protection threshold; The second threshold range is determined based on the upper limit and the lower limit.

4. An overcurrent detection device, characterized in that, include: Memory, which stores programs or instructions; A processor that, when executing the program or instructions, implements the steps of the overcurrent detection method as described in claim 1 or 2.

5. A servo driver, characterized in that, include: The overcurrent detection device as described in claim 3 or 4.

6. A servo driver, characterized in that, include: A pulse width modulation device used to output pulse signals; The processor is configured to determine a second protection threshold and a third protection threshold based on the vector sum of the first phase current, the second phase current, and the third phase current being zero, according to a first protection threshold and the conversion relationship between the third phase current and the first and second phase currents; to determine a first threshold range according to the first protection threshold; and to determine a second threshold range according to the first protection threshold, the second protection threshold, and the third protection threshold. A first comparator is used to compare the first phase current with the first threshold range; A second comparator is used to compare the second phase current with the second threshold range; The processor is further configured to control the pulse width modulation device to operate based on the comparison results of the first comparator and the second comparator; The conversion relationship is used to indicate the expression of the third phase current with respect to the first phase current and the second phase current; The processor is specifically configured to determine the second protection threshold based on the negative of the first protection threshold and the difference between the first phase current; and to determine the third protection threshold based on the difference between the first protection threshold and the first phase current. The processor is specifically configured to determine a first threshold range based on the first protection threshold. The second threshold range is determined based on the first protection threshold, the second protection threshold, and the third protection threshold; Overcurrent detection is performed based on the comparison results of the first phase current and the first threshold range, and the comparison results of the second phase current and the second threshold range. The lower limit value is determined based on the larger of the opposite of the first protection threshold and the second protection threshold; The upper limit value is determined based on the smaller value between the first protection threshold and the third protection threshold; The second threshold range is determined based on the upper limit and the lower limit.

7. A readable storage medium, characterized in that, The readable storage medium stores a program or instructions that, when executed by a processor, implement the steps of the overcurrent detection method as described in claim 1 or 2.

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