Open-phase detection method and device, frequency converter, motor and electrical appliance

Abstract

This invention proposes a phase loss detection method and device, frequency converter, motor, and electrical equipment. The phase loss detection method includes: acquiring the three-phase currents and multiple sets of switching signals for the three phase bridge arms of a three-phase circuit, wherein each set of switching signals includes three switching signals, and the three switching signals correspond one-to-one with the three phase bridge arms; determining the space voltage vector corresponding to each set of switching signals; determining the corresponding sector position of each space voltage vector in a space vector coordinate system; and performing phase loss detection on the three-phase circuit based on the three-phase currents and the determined multiple sector positions. In this way, by combining the current phase current of the phase circuit with the sector position of the space voltage vector corresponding to the conduction status of the phase bridge arms in the space vector coordinate system, the system diagnoses whether the three-phase circuit is experiencing a phase loss and its location. Fault diagnosis is performed using the relationship between phases and phase currents, eliminating the need to consider high-frequency peak current interference and ensuring the accuracy of the phase loss detection results.

Description

Technical Field

[0001] This invention relates to the field of phase loss detection technology, and more specifically, to a phase loss detection method and apparatus, a frequency converter, a motor, and electrical equipment. Background Technology

[0002] In existing technologies, phase loss detection is performed by repeatedly judging whether the phase current is less than a certain threshold throughout the entire cycle. However, in actual operating conditions, there is high-frequency peak current interference. Therefore, even when a phase is missing, the phase current is not always less than a certain threshold due to the presence of high-frequency peak current. This is especially true when the actual operating current of the motor is relatively small, where the phase loss detection results are more significantly affected by high-frequency peak current interference.

[0003] Therefore, the existing phase loss detection methods are affected by high-frequency peak current interference, which makes them unable to effectively detect phase loss, reduces the accuracy of phase loss detection results, and easily leads to misjudgment. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0005] Therefore, the first aspect of the present invention is to provide a phase loss detection method.

[0006] A second aspect of the present invention is to provide a phase loss detection device.

[0007] The third aspect of the present invention is to provide a frequency converter.

[0008] The fourth aspect of the present invention is to provide a frequency converter.

[0009] The fifth aspect of the present invention is to provide an electric motor.

[0010] The sixth aspect of the present invention is to provide an electrical device.

[0011] The seventh aspect of the present invention is to provide a readable storage medium.

[0012] In view of this, according to one aspect of the present invention, a phase loss detection method is proposed, the method comprising: acquiring three-phase currents and multiple sets of switching signals of three phase bridge arms of a three-phase circuit, wherein each set of switching signals includes three switching signals, and the three switching signals correspond one-to-one with the three phase bridge arms; determining the space voltage vector corresponding to each set of switching signals; determining the corresponding sector position of each space voltage vector in a space vector coordinate system; and performing phase loss detection on the three-phase circuit based on the three-phase currents and the determined multiple sector positions.

[0013] The phase loss detection method provided by this invention is used to detect phase loss in a three-phase circuit. The three-phase circuit includes three phase bridge arms, each corresponding to one phase (U-phase, V-phase, or W-phase). During use, the conduction state of the upper and lower bridge arms of the three phase bridge arms is adjusted to generate corresponding phase currents (U-phase current, V-phase current, and W-phase current). Specifically, each phase bridge arm is equipped with a circuit switch. By controlling the opening or closing of the circuit switch on the phase bridge arm, the conduction state of the upper and lower bridge arms of the corresponding phase bridge arm is controlled.

[0014] The phase loss detection method provided by this invention detects the phase currents of phases U, V, and W in a three-phase circuit at the previous moment, i.e., detects the current of phase U, phase V, and phase W in the three-phase circuit at the current moment. Simultaneously, it acquires the switching signals of the circuit switches on the three phase bridge arms of the three-phase circuit at the current moment and the previous moment, respectively. The switching signals of the three phase bridge arms at the current moment form one set of switching signals, and the switching signals of the three phase bridge arms at the previous moment form another set of switching signals. Based on this, two space voltage vectors are determined according to the two sets of switching signals, i.e., the corresponding space voltage vectors are determined according to the conduction state of the three phase bridge arms. Further, the sector position in the space vector coordinate system is determined according to each determined space voltage vector to obtain multiple sector positions, and then combined with the detected three phase currents and multiple sector positions, phase loss detection is performed on the three-phase circuit.

[0015] Thus, the phase loss detection method provided by this invention, when detecting phase loss in a three-phase circuit, combines the current phase current of the three-phase circuit with the sector position of the space voltage vector corresponding to the conduction status of the phase bridge arm in the space vector coordinate system to diagnose whether the three-phase circuit is missing a phase. It uses the relationship between phases and phase currents for fault diagnosis, and there is no problem of limiting the phase loss threshold current. Therefore, there is no need to consider the problem of high-frequency peak current interference. It can effectively detect the phase loss state of the three-phase circuit, ensure the accuracy of the phase loss detection results, and avoid the occurrence of misjudgment.

[0016] Furthermore, based on the control principle of space voltage vector, when the switching frequency of the circuit switches on the three phase bridge arms is high, the flux linkage trajectory approaches a quasi-circular shape, thereby achieving motor control. At non-zero basic voltage vector locations, phase peak voltages will appear; that is, when the sector of the space voltage vector in the space vector coordinate system switches, a phase peak voltage will occur, and the magnitude relationship of the phase currents will also exhibit a regular change. Therefore, the phase loss detection method proposed in this invention uses the relationship between phases and phase currents for fault diagnosis. Specifically, by combining the current phase current of the three-phase circuit with the sector position of the space voltage vector in the space vector coordinate system corresponding to the conduction status of the phase bridge arms, the method diagnoses whether the three-phase circuit is missing a phase, ensuring the accuracy of the phase loss detection results.

[0017] Furthermore, when acquiring multiple sets of switching signals from the three phase bridge arms in a three-phase circuit, two sets of switching signals can be acquired within a short time interval at the initial detection moment. The corresponding space voltage vectors are then determined based on these two sets of signals, and the corresponding two sector positions are obtained from these two determined space voltage vectors. Phase loss detection is then performed based on the two sector positions and the detected phase current. The determined sector positions can be recorded. During intermediate detection moments, only one set of switching signals from the three phase bridge arms at the current moment needs to be acquired, and the corresponding sector position is obtained through the above steps. This is then combined with the most recently recorded historical sector position and the current phase current for phase loss detection. This avoids repetitive work, improving phase loss detection efficiency while saving computational resources.

[0018] Therefore, in the phase loss detection method proposed in this invention, the three-phase currents of the three-phase circuit and multiple sets of switching signals of the three phase bridge arms are acquired. A corresponding space voltage vector is determined based on each set of switching signals, resulting in multiple space voltage vectors. Then, multiple sector positions are obtained based on these multiple space voltage vectors. Finally, phase loss detection is performed based on the multiple sector positions and the current three-phase currents. In this way, fault diagnosis is performed using the relationship between phases and phase currents, eliminating the problem of limiting the phase loss threshold current and thus avoiding the need to consider high-frequency spike current interference. This effectively detects the phase loss state of the three-phase circuit and ensures the accuracy of the phase loss detection results.

[0019] The phase loss detection method according to the present invention may also have the following additional technical features:

[0020] In the above technical solution, determining the space voltage vector corresponding to each group of switching signals specifically includes: determining the conduction state of the phase bridge arm corresponding to each switching signal; assigning a value to each switching signal according to the conduction state; and determining the corresponding space voltage vector based on the value assignment result of each group of switching signals.

[0021] In this technical solution, the specific method for determining the corresponding space voltage vector using each set of switching signals of the three phase bridge arms is defined. Specifically, when determining the corresponding space voltage vector using each set of switching signals, for each set of switching signals, the conduction state of the three corresponding phase bridge arms is determined by the three switching signals, where there is a one-to-one correspondence between the switching signals and the phase bridge arms. Based on this, the corresponding switching signals are assigned values ​​based on the conduction state of the phase bridge arms, and then the space voltage vector corresponding to the set of switching signals is determined by the value assignment results of the three phase bridge arms. This process is repeated for other sets of switching signals, ultimately yielding multiple space voltage vectors.

[0022] It is understandable that the space voltage vector is related to the conduction state of the three phase bridge arms, which can be described by the switching signals of the circuit switches on them. Therefore, in this technical solution, the conduction state of the corresponding phase bridge arm is determined by the switching signal, and then the corresponding space voltage vector is determined by the conduction state of the phase bridge arm, ensuring an accurate correspondence between the determined space voltage vector and the conduction state of the phase bridge arm, and ensuring the accuracy of the space voltage vector determination.

[0023] In any of the above technical solutions, each switch signal is assigned a value based on its conduction state, specifically including: when the upper bridge arm of the phase bridge arm is on and the lower bridge arm of the phase bridge arm is off, the switch signal is assigned a first flag value; when the upper bridge arm of the phase bridge arm is off and the lower bridge arm of the phase bridge arm is on, the switch signal is assigned a second flag value; wherein, the first flag value and the second flag value are binary values.

[0024] In this technical solution, the specific method for assigning values ​​to the corresponding switch signals based on the conduction state of the phase bridge arm is defined. Specifically, each phase bridge arm in the three-phase circuit may include an upper bridge arm and a lower bridge arm, each equipped with a circuit switch. The conduction state of the upper and lower bridge arms is controlled by closing and opening the circuit switches, thereby controlling the overall conduction state of the phase bridge arm. Therefore, when assigning values ​​to the corresponding switch signals based on the conduction state of the phase bridge arm, the assignment is specifically based on the conduction state of the upper and lower bridge arms within each phase bridge arm.

[0025] Specifically, for each phase bridge arm, when the upper bridge arm of the phase bridge arm is in a conducting state and the lower bridge arm is in a non-conducting state (i.e., only the upper bridge arm of the phase bridge arm is conducting), a first flag value is assigned to mark the switching signal corresponding to that phase bridge arm. Conversely, when the upper bridge arm of the phase bridge arm is in a non-conducting state and the lower bridge arm is in a conducting state (i.e., only the lower bridge arm of the phase bridge arm is conducting), a second flag value is assigned to mark the switching signal corresponding to that phase bridge arm. This process is repeated for the switching signals of the other phase bridge arms. Based on the marking results of the switching signals of the three phase bridge arms, the space voltage vector corresponding to this set of switching signals is determined.

[0026] Additionally, it should be noted that during the switching process of the phase bridge arm conduction state, that is, during the change of the switching signal, the switching signal is assigned a value and marked according to the conduction state before the phase bridge arm conduction state switching.

[0027] The first and second flag values ​​mentioned above are both binary values, that is, the first and second flag values ​​are 0 or 1.

[0028] In this technical solution, specifically, the first flag value is 1 and the second flag value is 0. That is, when only the upper bridge arm is conducting in the phase bridge arm, the switch signal corresponding to that phase bridge arm is marked as "1", while when only the lower bridge arm is conducting in the phase bridge arm, the switch signal corresponding to that phase bridge arm is marked as "0".

[0029] In any of the above technical solutions, the corresponding space voltage vector is determined based on the assignment mark result of each group of switch signals, specifically including: sorting the assignment mark values ​​of each switch signal according to a preset order to obtain the corresponding binary code; and determining the binary code as the space voltage vector.

[0030] In this technical solution, the specific method for determining the corresponding space voltage vector by assigning a value to each group of switch signals is defined. Specifically, each switch signal is assigned a value using binary values. Therefore, when determining the corresponding space voltage vector by assigning a value to each group of switch signals, the assigned value (i.e., the corresponding binary value) of the three switch signals in each group is sorted in a preset order to obtain a three-bit binary code. This binary code can represent the space voltage vector corresponding to that group of switch signals.

[0031] Specifically, each group of three switching signals corresponds one-to-one with each of the three phase bridge arms. The assigned values ​​of the three switching signals in each group are sorted from left to right according to the order of U phase, V phase, and W phase. That is, the assigned value of the switching signal of the U phase bridge arm is on the left, the assigned value of the switching signal of the V phase bridge arm is in the middle, and the assigned value of the switching signal of the W phase bridge arm is on the right, thus obtaining a three-bit binary code, namely the space voltage vector.

[0032] In any of the above technical solutions, the space vector coordinate system includes multiple sectors. Determining the corresponding sector position of each space voltage vector in the space vector coordinate system specifically includes: determining the corresponding sector of each space voltage vector in multiple sectors according to a preset correspondence.

[0033] In this technical solution, the aforementioned spatial vector coordinate system is divided into multiple sectors. Based on this, the technical solution specifies the particular method for determining the sector position in the spatial vector coordinate system using the spatial voltage vector. Specifically, the sector position of the spatial voltage vector in the spatial vector coordinate system is determined according to the preset correspondence between the spatial voltage vector and the multiple sectors in the spatial vector coordinate system. That is, a sector is determined from the multiple sectors in the spatial vector coordinate system as the corresponding sector of the spatial voltage vector.

[0034] The aforementioned space voltage vector is represented by a three-bit binary code. Therefore, when determining the sector position of the space voltage vector in the space vector coordinate system, a binary conversion algorithm can be used to decode the binary code corresponding to the space voltage vector into a decimal number, which is then used to represent the space voltage vector. For example, the space voltage vector "010" can be denoted as U2, and the space voltage vector "011" can be denoted as U3.

[0035] Specifically, based on the six non-zero basic voltage vectors, the spatial vector coordinate system containing the spatial voltage vectors is divided into six sectors, with each of the upper and lower parts of the spatial vector coordinate system comprising three sectors. Treating this spatial vector coordinate system as a two-dimensional coordinate system, and taking the positive axis of the horizontal coordinate as the starting line, the six sectors are sequentially designated as sector 1, sector 2, sector 3, sector 4, sector 5, and sector 6 in a counter-clockwise order. Based on this, sector 1 is located between spatial voltage vectors U4(100) and U6(110), sector 2 is located between U6(110) and U2(010), sector 3 is located between U2(010) and U3(011), sector 4 is located between U3(011) and U1(001), sector 5 is located between U1(001) and U5(101), and sector 6 is located between U5(101) and U4(100).

[0036] Furthermore, during the switching process of the phase bridge arm's conduction state, that is, during the transition of the switching signal, the switching signal is assigned a value according to the conduction state before the phase bridge arm's conduction state switching. Therefore, when determining the sector position in the spatial vector coordinate system through the spatial voltage vector, the sector number of the spatial voltage vector in the spatial vector coordinate system can be determined by combining the specific spatial voltage vector and the sector switching direction (the change in the switching signal).

[0037] That is, when the sector switching direction is clockwise, the preset correspondence between the aforementioned spatial voltage vector and multiple sectors in the spatial vector coordinate system is as follows: U1 (001) corresponds to the fourth sector, U2 (010) corresponds to the second sector, U3 (011) corresponds to the third sector, U4 (100) corresponds to the sixth sector, U5 (101) corresponds to the fifth sector, and U6 (110) corresponds to the first sector. When the sector switching direction is counterclockwise, the preset correspondence between the aforementioned spatial voltage vector and multiple sectors in the spatial vector coordinate system is as follows: U1 (001) corresponds to the fifth sector, U2 (010) corresponds to the third sector, U3 (011) corresponds to the fourth sector, U4 (100) corresponds to the first sector, U5 (101) corresponds to the sixth sector, and U6 (110) corresponds to the second sector. It should be noted that the correspondence between the two zero vectors U0(000) and U7(111) and the aforementioned sectors is the same as that between U4(100).

[0038] In any of the above technical solutions, the three-phase circuit is subjected to phase loss detection based on the three-phase phase current and the determined multiple sector positions. Specifically, this includes: determining the current sector switching state of the space voltage vector in the space vector coordinate system based on the multiple sector positions; and performing phase loss detection on the three-phase circuit based on the current time as the sector switching time and the three-phase phase current.

[0039] This technical solution specifies the method for phase loss detection using predetermined sector positions and detected three-phase currents. Specifically, when detecting phase loss using predetermined sector positions and detected three-phase currents, the method first determines the sector switching state of the space voltage vector's current sector position in the space vector coordinate system. If the sector position of the space voltage vector in the space vector coordinate system changes at the current moment (i.e., if the current moment is a sector switching moment), the three-phase circuit phase loss is detected based on the correspondence between the detected three-phase currents and the predetermined sector switching states. This method detects phase loss by using the correspondence between the current phase currents and the predetermined sector switching states, effectively diagnosing three-phase circuit faults using the correspondence between phase currents and phases. It eliminates the need to limit the phase loss threshold current, thus avoiding interference from high-frequency peak currents and ensuring the accuracy of the phase loss detection results, thereby preventing misjudgments.

[0040] In any of the above technical solutions, the three-phase circuit is subjected to phase loss detection based on the sector switching status and the three-phase current, specifically including: comparing the magnitude of the three-phase current; and performing phase loss detection on the three-phase circuit based on the comparison result and the sector switching status.

[0041] This technical solution defines the specific method for detecting phase loss in a three-phase circuit by establishing the correspondence between the current phase currents and the determined sector switching state. Specifically, when the current moment is determined to be a sector switching moment, the magnitudes of the currently detected three-phase phase currents are compared. The phase loss state of the three-phase circuit is then detected by combining the comparison results with the current sector switching state. This method of fault diagnosis using the correspondence between phase currents and phases, specifically by combining the comparison results of the three-phase phase currents with the current sector switching state, eliminates the need to limit the phase loss threshold current. Therefore, it avoids the interference of high-frequency peak currents on the detection results, effectively detecting the phase loss state of the three-phase circuit and ensuring the accuracy of the phase loss detection results, thus preventing misjudgments.

[0042] In any of the above technical solutions, the three-phase circuit is subjected to phase loss detection based on the comparison result and the sector switching state, specifically including: based on the sector switching state being a first switching state, if the comparison result is detected to not meet the first preset condition for a consecutive preset number of times, the U phase of the three-phase circuit is determined to be missing; based on the sector switching state being a second switching state, if the comparison result is detected to not meet the second preset condition for a consecutive preset number of times, the V phase of the three-phase circuit is determined to be missing; based on the sector switching state being a third switching state, if the comparison result is detected to not meet the third preset condition for a consecutive preset number of times, the W phase of the three-phase circuit is determined to be missing.

[0043] In this technical solution, the specific method for detecting phase loss by combining the comparison results of the three-phase current magnitudes and the corresponding relationship between the specific sector switching state is defined. Specifically, if the actual sector switching state is the first switching state, but the comparison results of the three-phase current magnitudes fail to meet the first preset condition for a preset number of consecutive times, the U-phase of the current three-phase circuit is determined to be missing; if the actual sector switching state is the second switching state, but the comparison results of the three-phase current magnitudes fail to meet the second preset condition for a preset number of consecutive times, the V-phase of the current three-phase circuit is determined to be missing; if the actual sector switching state is the third switching state, but the comparison results of the three-phase current magnitudes fail to meet the third preset condition for a preset number of consecutive times, the W-phase of the current three-phase circuit is determined to be missing. In this way, by combining the comparison results of the specific three-phase current magnitudes and the current actual sector switching status, the phase loss status and specific location of the three-phase circuit can be diagnosed. There is no problem of limiting the phase loss threshold current, so there is no need to consider the interference of high-frequency peak current on the detection results. The phase loss status of the three-phase circuit can be effectively detected, ensuring the accuracy of the phase loss detection results and avoiding the occurrence of misjudgment.

[0044] It should be noted that, to ensure the accuracy of the test results, the preset number of tests can be limited to N, where N is an integer greater than or equal to 100. In practical applications, N can take specific values ​​such as 100, 150, 200, 250, and 300, and no specific restriction is imposed here.

[0045] In any of the above technical solutions, the first switching state is: the sector position of the space voltage vector in the space vector coordinate system is switched from the first sector to the sixth sector; the first preset condition is: the U-phase current is greater than the V-phase current, and the U-phase current is greater than the W-phase current; the second switching state is: the sector position of the space voltage vector in the space vector coordinate system is switched from the third sector to the second sector; the second preset condition is: the V-phase current is greater than the U-phase current, and the V-phase current is greater than the W-phase current; the third switching state is: the sector position of the space voltage vector in the space vector coordinate system is switched from the fifth sector to the fourth sector; the third preset condition is: the W-phase current is greater than the U-phase current, and the W-phase current is greater than the V-phase current.

[0046] In this technical solution, the specific judgment conditions for diagnosing the phase loss state of a three-phase circuit by comparing the magnitudes of the specific three-phase currents and the current actual sector switching state are defined. Specifically, the first switching state is: the sector corresponding to the space voltage vector switches from the first sector to the sixth sector, and the first preset condition is: among the U-phase current, V-phase current, and W-phase current, the U-phase current has the largest current value. Further, the second switching state is: the sector corresponding to the space voltage vector switches from the third sector to the second sector, and the second preset condition is: among the U-phase current, V-phase current, and W-phase current, the V-phase current has the largest current value. Further, the third switching state is: the sector corresponding to the space voltage vector switches from the fifth sector to the fourth sector, and the third preset condition is: among the U-phase current, V-phase current, and W-phase current, the W-phase current has the largest current value.

[0047] In other words, in the phase loss detection method proposed in this invention, if the actual sector switching state is from the first sector to the sixth sector, and the current value of the U-phase current is not the maximum value among the three phases (U-phase current, V-phase current, and W-phase current) after a preset number of consecutive detections, then the current value of the U-phase current in the current three-phase circuit is determined to be missing in phase U; if the actual sector switching state is from the third sector to the second sector, and the current value of the V-phase current is not the maximum value among the three phases (U-phase current, V-phase current, and W-phase current) after a preset number of consecutive detections, then the current value of the V-phase current in the current three-phase circuit is determined to be missing in phase V; if the actual sector switching state is from the fifth sector to the fourth sector, and the current value of the W-phase current is not the maximum value among the three phases (U-phase current, V-phase current, and W-phase current) after a preset number of consecutive detections, then the current value of the W-phase current in the current three-phase circuit is determined to be missing in phase W. In this way, by combining the comparison results of the current values ​​of the U-phase current, V-phase current, and W-phase current, as well as the current actual sector switching status, the phase loss status and specific location of the three-phase circuit can be diagnosed. There is no problem of limiting the phase loss threshold current, so there is no need to consider the interference of high-frequency peak current on the detection results. The phase loss status of the three-phase circuit can be effectively detected, ensuring the accuracy of the phase loss detection results and avoiding the occurrence of misjudgment.

[0048] According to a second aspect of the present invention, a phase loss detection device is provided, the device comprising: an acquisition unit for acquiring three-phase phase currents and multiple sets of switching signals of three phase bridge arms of a three-phase circuit, wherein each set of switching signals includes three switching signals, and the three switching signals correspond one-to-one with the three phase bridge arms; a processing unit for determining a space voltage vector corresponding to each set of switching signals; the processing unit is further configured to determine the corresponding sector position of each space voltage vector in a space vector coordinate system; and the processing unit is further configured to perform phase loss detection on the three-phase circuit based on the three-phase phase currents and the determined multiple sector positions.

[0049] The phase loss detection device provided by this invention is used to detect phase loss in a three-phase circuit. The three-phase circuit includes three phase bridge arms, each corresponding to one phase (U phase, V phase, or W phase). During use, the conduction state of the upper and lower bridge arms of the three phase bridge arms is adjusted to generate corresponding phase currents (U phase current, V phase current, and W phase current). Specifically, each phase bridge arm is equipped with a circuit switch. By controlling the opening or closing of the circuit switch on the phase bridge arm, the conduction state of the upper and lower bridge arms of the corresponding phase bridge arm is controlled.

[0050] The phase loss detection device provided by this invention acquires the phase currents of phases U, V, and W in a three-phase circuit at the previous moment through an acquisition unit, i.e., it acquires the current of phase U, phase V, and phase W in the three-phase circuit at the current moment through the acquisition unit. Simultaneously, the acquisition unit also acquires the switching signals of the circuit switches on the three phase bridge arms of the three-phase circuit at the current moment and the previous moment, respectively. The switching signals of the three phase bridge arms at the current moment form one set of switching signals, and the switching signals of the three phase bridge arms at the previous moment form another set of switching signals. Based on this, the processing unit determines two space voltage vectors according to the two sets of switching signals acquired by the acquisition unit, i.e., the processing unit determines the corresponding space voltage vectors according to the conduction state of the three phase bridge arms. Further, the processing unit determines the sector position of each determined space voltage vector in the space vector coordinate system to obtain multiple sector positions. Then, the processing unit combines the detected three phase currents and multiple sector positions to perform phase loss detection on the three-phase circuit.

[0051] Thus, the phase loss detection device provided by this invention, when performing phase loss detection on a three-phase circuit, combines the current phase current of the three-phase circuit with the sector position of the space voltage vector corresponding to the conduction status of the phase bridge arm in the space vector coordinate system to diagnose whether the three-phase circuit is missing a phase. It uses the relationship between phases and phase currents for fault diagnosis, and there is no problem of limiting the phase loss threshold current. Therefore, there is no need to consider the problem of high-frequency peak current interference. It can effectively detect the phase loss state of the three-phase circuit, ensure the accuracy of the phase loss detection results, and avoid the occurrence of misjudgment.

[0052] In this process, when acquiring multiple sets of switching signals from the three phase bridge arms of a three-phase circuit using the acquisition unit, two sets of switching signals can be acquired within a short time interval at the initial detection moment. The corresponding space voltage vectors are then determined based on these two sets of signals, and the corresponding two sector positions are obtained from these two determined space voltage vectors. Phase loss detection is then performed based on the two sector positions and the detected phase current. The determined sector positions can be recorded. During intermediate detection moments, only one set of switching signals from the three phase bridge arms at the current moment needs to be acquired by the acquisition unit, and the corresponding sector position is obtained through the above steps. This is then combined with the most recently recorded historical sector position and the current phase current to perform phase loss detection. This avoids repetitive work, improving phase loss detection efficiency while saving computational resources.

[0053] Therefore, in the phase loss detection device proposed in this invention, the acquisition unit acquires the three-phase currents of the three-phase circuit and multiple sets of switching signals of the three phase bridge arms. The processing unit determines the corresponding space voltage vector based on each set of switching signals, thereby obtaining multiple space voltage vectors. The processing unit then obtains multiple sector positions based on these space voltage vectors. Finally, the processing unit performs phase loss detection based on the multiple sector positions and the current three-phase currents. In this way, fault diagnosis is performed using the relationship between phase and phase currents, eliminating the problem of limiting the phase loss threshold current and thus avoiding the need to consider high-frequency spike current interference. This effectively detects the phase loss state of the three-phase circuit and ensures the accuracy of the phase loss detection results.

[0054] According to a third aspect of the present invention, a frequency converter is provided, comprising: a memory storing a program or instructions; and a processor, which, when executing the program or instructions, implements the steps of the phase loss detection method as described in any of the above-described technical solutions. Therefore, the frequency converter proposed in the third aspect of the present invention possesses all the beneficial effects of the phase loss detection method in any of the technical solutions of the first aspect, which will not be elaborated further here.

[0055] According to a fourth aspect of the present invention, a frequency converter is provided, comprising: the phase loss detection device described in the above-described technical solution. Therefore, the frequency converter proposed in the fourth aspect of the present invention possesses all the beneficial effects of the phase loss detection device in the second aspect of the technical solution described above, and will not be elaborated further here.

[0056] According to a fifth aspect of the present invention, a motor is provided, comprising the frequency converter described in the third aspect of the technical solution above, or the frequency converter described in the fourth aspect of the technical solution above. Therefore, the motor proposed in the fifth aspect of the present invention possesses all the beneficial effects of the frequency converter described in the third aspect of the technical solution above, or the motor possesses all the beneficial effects of the frequency converter described in the fourth aspect of the technical solution above, which will not be elaborated further here.

[0057] According to a sixth aspect of the present invention, an electrical device is provided, comprising: the motor described in the fifth aspect of the technical solution above. Therefore, the electrical device proposed in the sixth aspect of the present invention possesses all the beneficial effects of the motor described in the fifth aspect of the technical solution above, which will not be elaborated further here.

[0058] The aforementioned electrical appliances are not limited to products such as electric fans, refrigerators, and washing machines, and no specific restrictions are imposed here.

[0059] According to a seventh 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 phase loss detection method as described in any of the above-described technical solutions. Therefore, the readable storage medium proposed in the seventh aspect of the present invention possesses all the beneficial effects of the phase loss detection method in any of the technical solutions of the first aspect, and will not be elaborated further here.

[0060] 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

[0061] 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:

[0062] Figure 1 One of the schematic flowcharts of the phase loss detection method according to an embodiment of the present invention is shown;

[0063] Figure 2 A second schematic flowchart of the phase loss detection method according to an embodiment of the present invention is shown;

[0064] Figure 3 The third schematic flowchart of the phase loss detection method according to an embodiment of the present invention is shown;

[0065] Figure 4 The fourth schematic flowchart of the phase loss detection method according to an embodiment of the present invention is shown;

[0066] Figure 5 The fifth schematic flowchart of the phase loss detection method according to an embodiment of the present invention is shown;

[0067] Figure 6 The sixth schematic flowchart of the phase loss detection method according to an embodiment of the present invention is shown;

[0068] Figure 7 The seventh flowchart of the phase loss detection method according to an embodiment of the present invention is shown;

[0069] Figure 8 The eighth schematic flowchart of the phase loss detection method according to an embodiment of the present invention is shown;

[0070] Figure 9 A flowchart of the phase loss detection method according to an embodiment of the present invention is shown in Figure 9.

[0071] Figure 10 A structural block diagram of a phase loss detection device according to an embodiment of the present invention is shown;

[0072] Figure 11 One of the structural block diagrams of the frequency converter according to an embodiment of the present invention is shown;

[0073] Figure 12 A second structural block diagram of the frequency converter according to an embodiment of the present invention is shown;

[0074] Figure 13 One of the structural block diagrams of the motor according to an embodiment of the present invention is shown;

[0075] Figure 14 A second structural block diagram of the motor according to an embodiment of the present invention is shown;

[0076] Figure 15 One of the structural block diagrams of an electrical device according to an embodiment of the present invention is shown;

[0077] Figure 16 A second structural block diagram of an electrical device according to an embodiment of the present invention is shown;

[0078] Figure 17 A three-phase circuit diagram according to an embodiment of the present invention is shown;

[0079] Figure 18 A schematic diagram of high-frequency spike current interference according to an embodiment of the present invention is shown;

[0080] Figure 19 A schematic diagram of a quasi-circular magnetic flux trajectory according to an embodiment of the present invention is shown;

[0081] Figure 20 A sector distribution diagram of the spatial vector coordinate system according to an embodiment of the present invention is shown. Detailed Implementation

[0082] 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.

[0083] 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.

[0084] The following is combined with Figures 1 to 20 The present application provides a detailed description of the phase loss detection method and device, frequency converter, motor and electrical equipment provided in the embodiments of this application through specific implementation methods and application scenarios.

[0085] Example 1, Figure 1 A schematic flowchart of one embodiment of the phase loss detection method of the present invention is shown. The detection method includes the following steps S102 to S108:

[0086] Step S102: Obtain the three-phase currents of the three-phase circuit and multiple sets of switching signals for the three phase bridge arms;

[0087] Step S104: Determine the space voltage vector corresponding to each group of switching signals;

[0088] Step S106: Determine the corresponding sector position of each space voltage vector in the space vector coordinate system;

[0089] Step S108: Perform phase loss detection on the three-phase circuit based on the three-phase phase current and the determined positions of multiple sectors;

[0090] Each set of switching signals includes three switching signals, and there is a one-to-one correspondence between the three switching signals and the three phase bridge arms.

[0091] The phase loss detection method proposed in this invention is used for phase loss detection in a three-phase circuit. For example... Figure 17 As shown, the three-phase circuit includes three phase bridge arms, each corresponding to one phase of the three-phase circuit, namely phase U, phase V, or phase W (i.e., phase A, phase B, or phase C). During use, the corresponding phase currents (phase U current, phase V current, and phase W current) are generated by adjusting the conduction state of the upper and lower bridge arms of the three phase bridge arms. Specifically, each phase bridge arm is equipped with a circuit switch. By controlling the opening or closing of the circuit switch on the phase bridge arm, the conduction state of the upper and lower bridge arms of the corresponding phase bridge arm is controlled.

[0092] The phase loss detection method provided in this invention detects the phase currents of phases U, V, and W in a three-phase circuit at the previous moment, i.e., it detects the current of phase U, phase V, and phase W in the three-phase circuit at the current moment. Simultaneously, it acquires the switching signals of the circuit switches on the three phase bridge arms of the three-phase circuit at the current moment and the previous moment. The switching signals of the three phase bridge arms at the current moment form one set of switching signals, and the switching signals of the three phase bridge arms at the previous moment form another set of switching signals. Based on this, two space voltage vectors are determined according to the two sets of switching signals, i.e., the corresponding space voltage vectors are determined according to the conduction state of the three phase bridge arms. Further, the sector position in the space vector coordinate system is determined according to each determined space voltage vector to obtain multiple sector positions. Then, combined with the detected three phase currents and multiple sector positions, phase loss detection is performed on the three-phase circuit.

[0093] Thus, the phase loss detection method provided in this embodiment of the invention, when detecting phase loss in a three-phase circuit, combines the current phase current of the three-phase circuit with the sector position of the space voltage vector corresponding to the conduction status of the phase bridge arm in the space vector coordinate system to diagnose whether the three-phase circuit is missing a phase. It uses the relationship between phases and phase currents for fault diagnosis, eliminating the problem of a phase loss threshold current limitation, and therefore eliminating the need to consider high-frequency peak current interference (such as...). Figure 18 As shown in the figure, this method can effectively detect the phase loss status of a three-phase circuit, ensuring the accuracy of the phase loss detection results and avoiding misjudgment.

[0094] Among them, the space voltage vector is a type of control vector in the variable frequency speed control system. The space voltage vector is based on the overall generation effect of the three-phase waveform, with the aim of approximating the ideal circular rotating magnetic field trajectory of the motor air gap. It generates a three-phase modulated waveform in one step and controls it by approximating the circle with an inscribed polygon.

[0095] Furthermore, the space voltage vector is related to the conduction state of the three phase bridge arms. Based on the conduction state of the three phase bridge arms, the space voltage vector can include eight basic voltage vectors. Among these eight basic voltage vectors, two are zero vectors and six are non-zero vectors. Based on the six non-zero basic voltage vectors, the space vector coordinate system containing the space voltage vector is divided into six sectors, denoted as the first sector to the sixth sector.

[0096] Furthermore, according to the control principle of space voltage vector, when the switching frequency of the circuit switches on the three phase bridge arms is high, the flux linkage trajectory is close to a quasi-circular shape (e.g., Figure 19 As shown in the figure, motor control is achieved. At non-zero basic voltage vectors, phase peak voltages appear; that is, when the sector of the space voltage vector in the space vector coordinate system switches, phase peak voltages occur, and the magnitude relationship of the phase currents also exhibits a regular change. Therefore, the phase loss detection method proposed in this embodiment of the invention uses the relationship between phases and phase currents for fault diagnosis. Specifically, by combining the current phase current of the three-phase circuit and the sector position of the space voltage vector corresponding to the conduction status of the phase bridge arm in the space vector coordinate system, the accuracy of the phase loss detection result can be guaranteed.

[0097] Furthermore, when acquiring multiple sets of switching signals from the three phase bridge arms in a three-phase circuit, two sets of switching signals can be acquired within a short time interval at the initial detection moment. The corresponding space voltage vectors are then determined based on these two sets of signals, and the corresponding two sector positions are obtained from these two determined space voltage vectors. Phase loss detection is then performed based on the two sector positions and the detected phase current. The determined sector positions can be recorded. During intermediate detection moments, only one set of switching signals from the three phase bridge arms at the current moment needs to be acquired, and the corresponding sector position is obtained through the above steps. This is then combined with the most recently recorded historical sector position and the current phase current for phase loss detection. This avoids repetitive work, improving phase loss detection efficiency while saving computational resources.

[0098] Therefore, in the phase loss detection method proposed in this embodiment of the invention, the three-phase currents of the three-phase circuit and multiple sets of switching signals of the three phase bridge arms are acquired. A corresponding space voltage vector is determined based on each set of switching signals, thereby obtaining multiple space voltage vectors. Then, multiple sector positions are obtained based on these multiple space voltage vectors. Finally, phase loss detection is performed based on the multiple sector positions and the current three-phase currents. In this way, fault diagnosis is performed using the relationship between phases and phase currents, eliminating the problem of limiting the phase loss threshold current and thus avoiding the need to consider high-frequency spike current interference. This effectively detects the phase loss state of the three-phase circuit and ensures the accuracy of the phase loss detection results.

[0099] Example 2, Figure 2 A second schematic flowchart of a phase loss detection method according to an embodiment of the present invention is shown. The detection method includes the following steps S202 to S212:

[0100] Step S202: Obtain the three-phase current of the three-phase circuit and multiple sets of switching signals for the three phase bridge arms;

[0101] Step S204: Determine the conduction state of the phase bridge arm corresponding to each switch signal;

[0102] Step S206: Assign a value to each switch signal according to its conduction state;

[0103] Step S208: Determine the space voltage vector corresponding to each group of switching signals based on the assignment marking results;

[0104] Step S210: Determine the corresponding sector position of each space voltage vector in the space vector coordinate system;

[0105] Step S212: Perform phase loss detection on the three-phase circuit based on the three-phase phase current and the determined positions of multiple sectors;

[0106] Each set of switching signals includes three switching signals, and there is a one-to-one correspondence between the three switching signals and the three phase bridge arms.

[0107] In this embodiment, the specific method for determining the corresponding space voltage vector using each set of switching signals of the three phase bridge arms is defined. Specifically, when determining the corresponding space voltage vector using each set of switching signals, for each set of switching signals, the conduction state of the three corresponding phase bridge arms is determined by the three switching signals, wherein there is a one-to-one correspondence between the switching signals and the phase bridge arms. Based on this, the corresponding switching signals are marked with values ​​according to the conduction state of the phase bridge arms, and then the space voltage vector corresponding to the set of switching signals is determined by the marking results of the switching signals of the three phase bridge arms. This process is repeated for other sets of switching signals, ultimately yielding multiple space voltage vectors.

[0108] It is understandable that the space voltage vector is related to the conduction state of the three phase bridge arms, and the conduction state of the three phase bridge arms can be described by the switching signals of the circuit switches on them. Therefore, in this embodiment, the conduction state of the corresponding phase bridge arm is determined by the switching signal, and then the corresponding space voltage vector is determined by the conduction state of the phase bridge arm, ensuring the accurate correspondence between the determined space voltage vector and the conduction state of the phase bridge arm, and ensuring the accuracy of the space voltage vector determination.

[0109] Example 3, Figure 3 A third schematic flowchart of the phase loss detection method according to an embodiment of the present invention is shown. The detection method includes the following steps S302 to S314:

[0110] Step S302: Obtain the three-phase current of the three-phase circuit and multiple sets of switching signals for the three phase bridge arms;

[0111] Step S304: Determine the conduction state of the phase bridge arm corresponding to each switch signal;

[0112] Step S306: When the lower bridge arm of the phase bridge arm is in the open state and the upper bridge arm of the phase bridge arm is in the closed state, the switch signal is marked by assigning a value through the first flag value.

[0113] Step S308: When the lower bridge arm of the phase bridge arm is in the conducting state and the upper bridge arm of the phase bridge arm is in the disconnected state, the switch signal is marked by the second flag value.

[0114] Step S310: Determine the space voltage vector corresponding to each group of switching signals based on the assignment marking results;

[0115] Step S312: Determine the corresponding sector position of each space voltage vector in the space vector coordinate system;

[0116] Step S314: Perform phase loss detection on the three-phase circuit based on the three-phase phase current and the positions of multiple sectors;

[0117] Each set of switching signals includes three switching signals, and there is a one-to-one correspondence between the three switching signals and the three phase bridge arms; the first flag value and the second flag value are both binary values.

[0118] In this embodiment, based on Embodiment 2, the specific method for assigning values ​​to the corresponding switch signals based on the conduction state of the phase bridge arm is further defined. Specifically, each phase bridge arm in the three-phase circuit may include an upper bridge arm and a lower bridge arm, each equipped with a circuit switch. The conduction state of the upper and lower bridge arms is controlled by closing and opening the circuit switches, thereby controlling the overall conduction state of the phase bridge arm. Therefore, when assigning values ​​to the corresponding switch signals based on the conduction state of the phase bridge arm, the assignment can be based on the conduction state of the upper and lower bridge arms within each phase bridge arm.

[0119] Specifically, for each phase bridge arm, when the upper bridge arm of the phase bridge arm is in a conducting state and the lower bridge arm is in a non-conducting state (i.e., only the upper bridge arm of the phase bridge arm is conducting), a first flag value is assigned to mark the switching signal corresponding to that phase bridge arm. Conversely, when the upper bridge arm of the phase bridge arm is in a non-conducting state and the lower bridge arm is in a conducting state (i.e., only the lower bridge arm of the phase bridge arm is conducting), a second flag value is assigned to mark the switching signal corresponding to that phase bridge arm. This process is repeated for the switching signals of the other phase bridge arms. Based on the marking results of the switching signals of the three phase bridge arms, the space voltage vector corresponding to this set of switching signals is determined.

[0120] Additionally, it should be noted that during the switching process of the phase bridge arm conduction state, that is, during the change of the switching signal, the switching signal is assigned a value and marked according to the conduction state before the phase bridge arm conduction state switching.

[0121] The first and second flag values ​​mentioned above are both binary values, that is, the first and second flag values ​​are 0 or 1.

[0122] In this embodiment, specifically, the first flag value is 1 and the second flag value is 0. That is, when only the upper bridge arm is conducting in the phase bridge arm, the switch signal corresponding to that phase bridge arm is marked as "1", while when only the lower bridge arm is conducting in the phase bridge arm, the switch signal corresponding to that phase bridge arm is marked as "0".

[0123] For example, at a certain moment, the switching signals of the three phase bridge arms (U-phase bridge arm, V-phase bridge arm, and W-phase bridge arm) of a three-phase circuit are detected as (X, Y), (X, Y), and (Y, X), respectively. Here, the two characters in parentheses represent the on / off state of the circuit switch of the upper bridge arm in the phase bridge arm, and the latter represent the on / off state of the circuit switch of the lower bridge arm in the same phase bridge arm. Further, "X" indicates that the circuit switch is closed, and "Y" indicates that the circuit switch is open. Therefore, at this moment, only the upper bridge arm of the U-phase bridge arm in the three-phase circuit is conducting, so the switching signal of the U-phase bridge arm is marked as "1"; only the upper bridge arm of the V-phase bridge arm in the three-phase circuit is also conducting, so the switching signal of the V-phase bridge arm is also marked as "1"; and only the lower bridge arm of the W-phase bridge arm in the three-phase circuit is conducting, so the switching signal of the W-phase bridge arm is marked as "0". Based on this, the space voltage vector at that moment is determined by assigning and marking the switching signals of the U-phase bridge arm, V-phase bridge arm, and W-phase bridge arm.

[0124] It should be noted that the above expressions “(X, Y)” and “(Y, X)” are only for the purpose of clearly describing the technical solution provided by the present invention. In actual applications, there are many ways to express switching signals, and no specific limitations are made here.

[0125] Example 4, Figure 4 A fourth schematic flowchart of a phase loss detection method according to an embodiment of the present invention is shown. The detection method includes the following steps S402 to S416:

[0126] Step S402: Obtain the three-phase current of the three-phase circuit and multiple sets of switching signals for the three phase bridge arms;

[0127] Step S404: Determine the conduction state of the phase bridge arm corresponding to each switch signal;

[0128] Step S406: When the lower bridge arm of the phase bridge arm is in the open state and the upper bridge arm of the phase bridge arm is in the closed state, the switch signal is marked by assigning a value through the first flag value.

[0129] Step S408: When the lower bridge arm of the phase bridge arm is in the conducting state and the upper bridge arm of the phase bridge arm is in the disconnected state, the switch signal is marked by the second flag value.

[0130] Step S410: Sort the assignment mark values ​​of each switch signal according to a preset order to obtain the corresponding binary code;

[0131] Step S412: Determine the space voltage vector according to the binary code;

[0132] Step S414: Determine the corresponding sector position of each space voltage vector in the space vector coordinate system;

[0133] Step S416: Perform phase loss detection on the three-phase circuit based on the three-phase phase current and the positions of multiple sectors;

[0134] Each set of switching signals includes three switching signals, and there is a one-to-one correspondence between the three switching signals and the three phase bridge arms; the first flag value and the second flag value are both binary values.

[0135] In this embodiment, based on Embodiment 3, the specific method for determining the corresponding space voltage vector by assigning a value to each group of switch signals is further defined. Specifically, each switch signal is assigned a value using binary values. Therefore, when determining the corresponding space voltage vector by assigning a value to each group of switch signals, the assigned value (i.e., the corresponding binary value) of the three switch signals in each group is sorted in a preset order to obtain a three-bit binary code. This binary code can represent the space voltage vector corresponding to that group of switch signals.

[0136] Specifically, each group of three switching signals corresponds one-to-one with each of the three phase bridge arms. The assigned values ​​of the three switching signals in each group are sorted from left to right according to the order of U phase, V phase, and W phase. That is, the assigned value of the switching signal of the U phase bridge arm is on the left, the assigned value of the switching signal of the V phase bridge arm is in the middle, and the assigned value of the switching signal of the W phase bridge arm is on the right, thus obtaining a three-bit binary code, namely the space voltage vector.

[0137] For example, in a set of switching signals, based on the conduction state of the three phase bridge arms, the switching signals corresponding to the U-phase and W-phase bridge arms are both marked as "1", while the switching signal corresponding to the V-phase bridge arm is marked as "0". Therefore, by sorting the assigned values ​​of the three switching signals in this set from left to right according to the order of U-phase, V-phase, and W-phase, a three-bit binary code "101" is obtained. This binary code "101" can represent the space voltage vector corresponding to this set of switching signals.

[0138] Example 5, Figure 5Fifth schematic flowchart of the phase loss detection method according to an embodiment of the present invention is shown. The aforementioned spatial vector coordinate system includes multiple sectors, and the detection method includes the following steps S502 to S516:

[0139] Step S502: Obtain the three-phase current of the three-phase circuit and multiple sets of switching signals for the three phase bridge arms;

[0140] Step S504: Determine the conduction state of the phase bridge arm corresponding to each group of switch signals;

[0141] Step S506: When the lower bridge arm of the phase bridge arm is in the open state and the upper bridge arm of the phase bridge arm is in the closed state, the switch signal is marked by assigning a value through the first flag value.

[0142] Step S508: When the lower bridge arm of the phase bridge arm is in the conducting state and the upper bridge arm of the phase bridge arm is in the disconnected state, the switch signal is marked by the second flag value.

[0143] Step S510: Sort the assignment mark values ​​of each switch signal according to a preset order to obtain the corresponding binary code;

[0144] Step S512: Determine the space voltage vector according to the binary code;

[0145] Step S514: Determine the sector position of each space voltage vector in multiple sectors according to the preset correspondence relationship;

[0146] Step S516: Perform phase loss detection on the three-phase circuit based on the three-phase phase current and the positions of multiple sectors;

[0147] Each set of switching signals includes three switching signals, and there is a one-to-one correspondence between the three switching signals and the three phase bridge arms; the first flag value and the second flag value are both binary values.

[0148] In this embodiment, based on Embodiment 4, the aforementioned spatial vector coordinate system is further divided into multiple sectors. Furthermore, this embodiment further specifies the method for determining the sector position in the spatial vector coordinate system using the spatial voltage vector. Specifically, the sector position of the spatial voltage vector in the spatial vector coordinate system is determined according to the preset correspondence between the spatial voltage vector and the multiple sectors in the spatial vector coordinate system; that is, one sector is determined from the multiple sectors in the spatial vector coordinate system as the corresponding sector of the spatial voltage vector.

[0149] The aforementioned space voltage vector is represented by a three-bit binary code. Therefore, when determining the sector position of the space voltage vector in the space vector coordinate system, a binary conversion algorithm can be used to decode the binary code corresponding to the space voltage vector into a decimal number, which is then used to represent the space voltage vector. For example, the space voltage vector "010" can be denoted as U2, and the space voltage vector "011" can be denoted as U3.

[0150] Specifically, such as Figure 20 As shown, based on the six non-zero basic voltage vectors, the spatial vector coordinate system containing the spatial voltage vectors is divided into six sectors, with each of the upper and lower parts of the spatial vector coordinate system comprising three sectors. Treating this spatial vector coordinate system as a two-dimensional coordinate system, with the positive axis of the horizontal coordinate system as the starting line, and following a counter-clockwise order, these six sectors are sequentially designated as sector 1, sector 2, sector 3, sector 4, sector 5, and sector 6. Based on this, sector 1 is located between spatial voltage vectors U4(100) and U6(110), sector 2 is located between U6(110) and U2(010), sector 3 is located between U2(010) and U3(011), sector 4 is located between U3(011) and U1(001), sector 5 is located between U1(001) and U5(101), and sector 6 is located between U5(101) and U4(100).

[0151] Furthermore, during the switching process of the phase bridge arm's conduction state, that is, during the transition of the switching signal, the switching signal is assigned a value according to the conduction state before the phase bridge arm's conduction state switching. Therefore, when determining the sector position in the spatial vector coordinate system using the spatial voltage vector, the sector number of the spatial voltage vector in the spatial vector coordinate system can be determined by combining the specific spatial voltage vector and the sector switching direction (the change in the switching signal).

[0152] That is, when the sector switching direction is clockwise, the preset correspondence between the aforementioned spatial voltage vector and multiple sectors in the spatial vector coordinate system is as follows: U1 (001) corresponds to the fourth sector, U2 (010) corresponds to the second sector, U3 (011) corresponds to the third sector, U4 (100) corresponds to the sixth sector, U5 (101) corresponds to the fifth sector, and U6 (110) corresponds to the first sector. When the sector switching direction is counterclockwise, the preset correspondence between the aforementioned spatial voltage vector and multiple sectors in the spatial vector coordinate system is as follows: U1 (001) corresponds to the fifth sector, U2 (010) corresponds to the third sector, U3 (011) corresponds to the fourth sector, U4 (100) corresponds to the first sector, U5 (101) corresponds to the sixth sector, and U6 (110) corresponds to the second sector. It should be noted that the correspondence between the two zero vectors U0(000) and U7(111) and the aforementioned sectors is the same as that between U4(100).

[0153] In addition, in practical applications, the six sectors in the spatial vector coordinate system can be marked using sector numbers. Specifically, the sector numbers of the first to sixth sectors can be recorded as 1, 2, 3, 4, 5, and 6, respectively. Based on this, the decimal value obtained by decoding and converting the above-mentioned data is the sector number of the current sector of the spatial voltage vector in the spatial vector coordinate system.

[0154] For example, the space voltage vector corresponding to the first set of switching signals acquired by the three-phase circuit at the first moment is U3 (011), while the space voltage vector corresponding to the second set of switching signals acquired by the three-phase circuit at the second moment is U2 (010). Therefore, if the sector switching direction at both the first and second moments is clockwise, the space voltage vector of the three-phase circuit at the first moment is located in the third sector of the space vector coordinate system, i.e., the sector number corresponding to the space voltage vector of the three-phase circuit at the first moment is 3; while the space voltage vector of the three-phase circuit at the second moment is located in the second sector of the space vector coordinate system, i.e., the sector number corresponding to the space voltage vector of the three-phase circuit at the second moment is 2. In other words, during the time period from the first moment to the second moment, the sector position of the space voltage vector of the three-phase circuit in the space vector coordinate system changes from the third sector to the second sector.

[0155] Example 6, Figure 6 A sixth schematic flowchart of a phase loss detection method according to an embodiment of the present invention is shown. The detection method includes the following steps S602 to S610:

[0156] Step S602: Obtain the three-phase current of the three-phase circuit and multiple sets of switching signals for the three phase bridge arms;

[0157] Step S604: Determine the space voltage vector corresponding to each group of switching signals;

[0158] Step S606: Determine the corresponding sector position of each space voltage vector in the space vector coordinate system;

[0159] Step S608: Determine the current sector switching state of the space voltage vector in the space vector coordinate system based on multiple sector positions;

[0160] Step S610: When the current moment is a sector switching moment, perform phase loss detection on the three-phase circuit based on the three-phase phase current and sector switching status.

[0161] Each set of switching signals includes three switching signals, and there is a one-to-one correspondence between the three switching signals and the three phase bridge arms.

[0162] In this embodiment, based on any of the above embodiments, the specific method for phase loss detection using the determined multiple sector positions and the detected three-phase currents is further defined. Specifically, when performing phase loss detection using the determined multiple sector positions and the detected three-phase currents, firstly, based on the determined multiple sector positions, the sector switching state of the current sector position of the space voltage vector in the space vector coordinate system is determined. If it is determined that the sector position of the space voltage vector in the space vector coordinate system has changed at the current moment, that is, if it is determined that the current moment is a sector switching moment, then the three-phase circuit phase loss detection is performed based on the correspondence between the detected three-phase currents and the determined sector switching state. In this way, the circuit phase loss detection is performed by using the correspondence between the current phase current of the three-phase circuit and the determined sector switching state. That is, the fault diagnosis of the three-phase circuit is performed by using the correspondence between phase current and phase. There is no problem of limiting the phase loss threshold current. Therefore, there is no need to consider the interference of high-frequency peak current on the detection results. The phase loss state of the three-phase circuit can be effectively detected, ensuring the accuracy of the phase loss detection results and avoiding the occurrence of misjudgment.

[0163] Understandably, according to the control principle of space voltage vector, when the switching frequency of the circuit switches on the three phase bridge arms is high, the flux linkage trajectory is close to a quasi-circular shape, thus achieving motor control. At the non-zero basic voltage vector, a phase peak voltage will appear; that is, when the sector where the space voltage vector is located in the space vector coordinate system switches, a phase peak voltage will appear, and the magnitude relationship of the phase currents will also show a regular change. Therefore, the phase loss detection method proposed in this embodiment uses the correspondence between phase current and phase for fault diagnosis. Specifically, by combining the current phase current of the three-phase circuit with the aforementioned determined sector switching state, the accuracy of the phase loss detection result can be guaranteed.

[0164] Furthermore, it should be noted that the aforementioned spatial vector coordinate system is divided into six sectors, with each of the upper and lower parts comprising three sectors. Considering this spatial vector coordinate system as a two-dimensional coordinate system, and taking the positive horizontal axis as the starting line, these six sectors are sequentially designated as sector 1, sector 2, sector 3, sector 4, sector 5, and sector 6 in a counter-clockwise order. Based on this, the aforementioned spatial vector coordinate system also corresponds to the three phases of a three-phase circuit (i.e., phase U, phase V, and phase W). Specifically, taking the positive horizontal axis as the starting line, each phase is defined as 120 degrees in a counter-clockwise direction. Therefore, the aforementioned sector switching time refers to the switching time of the corresponding phases, namely: the switching time between sector 1 and sector 6, the switching time between sector 2 and sector 3, and the switching time between sector 4 and sector 5.

[0165] For example, if the sector position at the first moment is the second sector, the sector position at the second moment is the first sector, and the sector position at the third moment is the sixth sector. That is, from the first moment to the second moment, the sector position switches from the second sector to the first sector, and at this time, the phase loss state of the three-phase circuit is not detected; while from the second moment to the third moment, the sector position switches from the first moment to the sixth moment, and at this time, the phase loss state of the three-phase circuit is detected based on the detected three-phase current and the specific state of the sector switching.

[0166] Example 7, Figure 7 A schematic flowchart of a phase loss detection method according to an embodiment of the present invention is shown in Figure 7. The detection method includes the following steps S702 to S712:

[0167] Step S702: Obtain the three-phase current of the three-phase circuit and multiple sets of switching signals for the three phase bridge arms;

[0168] Step S704: Determine the space voltage vector corresponding to the group switch signal;

[0169] Step S706: Determine the corresponding sector position of each space voltage vector in the space vector coordinate system;

[0170] Step S708: Determine the current sector switching state of the space voltage vector in the space vector coordinate system based on multiple sector positions;

[0171] Step S710: When the current moment is a sector switching moment, compare the magnitudes of the three-phase currents.

[0172] Step S712: Perform phase loss detection on the three-phase circuit based on the sector switching status and the phase current magnitude comparison results;

[0173] Each set of switching signals includes three switching signals, and there is a one-to-one correspondence between the three switching signals and the three phase bridge arms.

[0174] In this embodiment, based on Embodiment Six, the specific method for detecting phase loss in the circuit by means of the correspondence between the current phase current of the three-phase circuit and the determined sector switching state is further defined. Specifically, when the current time is determined to be the sector switching time, the magnitudes of the currently detected three-phase phase currents are compared, and then the phase loss state of the three-phase circuit is detected by combining the comparison result of the three-phase current magnitudes and the current specific sector switching state. In this way, the fault diagnosis of the three-phase circuit is performed by using the correspondence between phase current and phase. Specifically, the phase loss state of the three-phase circuit is detected by combining the comparison result of the three-phase phase current magnitudes and the current specific sector switching state. There is no problem of limiting the phase loss threshold current, so there is no need to consider the interference of high-frequency peak current on the detection result. The phase loss state of the three-phase circuit can be effectively detected, ensuring the accuracy of the phase loss detection result and avoiding the occurrence of misjudgment.

[0175] Understandably, according to the control principle of space voltage vector, when the switching frequency of the circuit switches on the three phase bridge arms is high, the flux linkage trajectory is close to a quasi-circular shape, thus achieving motor control. At the non-zero basic voltage vector, a phase peak voltage will appear; that is, when the sector where the space voltage vector is located in the space vector coordinate system switches, a phase peak voltage will appear, and the magnitude relationship of the phase currents will also show a regular change. Therefore, the phase loss detection method proposed in this embodiment combines the comparison results of the three-phase current magnitudes with the correspondence between the specific sector switching states to diagnose whether a three-phase circuit is missing a phase, ensuring the accuracy of the phase loss detection results.

[0176] Example 8, Figure 8This is illustrated as a schematic flowchart of the phase loss detection method according to an embodiment of the present invention. The detection method includes the following steps S802 to S816:

[0177] Step S802: Obtain the three-phase current of the three-phase circuit and multiple sets of switching signals for the three phase bridge arms;

[0178] Step S804: Determine the space voltage vector corresponding to each group of switching signals;

[0179] Step S806: Determine the corresponding sector position of each space voltage vector in the space vector coordinate system;

[0180] Step S808: Determine the current sector switching state of the space voltage vector in the space vector coordinate system based on multiple sector positions;

[0181] Step S810: When the current moment is a sector switching moment, compare the magnitudes of the three-phase currents.

[0182] Step S812: If the comparison result does not meet the first preset condition for a consecutive preset number of times when the sector switching state is in the first switching state, it is determined that the U phase is missing.

[0183] Step S814: If the comparison result does not meet the second preset condition for a consecutive preset number of times when the sector switching state is in the second switching state, it is determined that phase V is missing.

[0184] Step S816: If the comparison result does not meet the third preset condition for a consecutive preset number of times when the sector switching state is in the third switching state, it is determined that phase W is missing.

[0185] Each set of switching signals includes three switching signals, and there is a one-to-one correspondence between the three switching signals and the three phase bridge arms.

[0186] In this embodiment, based on Embodiment Seven, the specific method for detecting phase loss by combining the comparison results of the three-phase current magnitudes and the correspondence between the specific sector switching states is further defined. Specifically, if the actual sector switching state is the first switching state, but the comparison results of the three-phase current magnitudes fail to meet the first preset condition for a preset number of consecutive times, the U-phase of the current three-phase circuit is determined to be missing; if the actual sector switching state is the second switching state, but the comparison results of the three-phase current magnitudes fail to meet the second preset condition for a preset number of consecutive times, the V-phase of the current three-phase circuit is determined to be missing; if the actual sector switching state is the third switching state, but the comparison results of the three-phase current magnitudes fail to meet the third preset condition for a preset number of consecutive times, the W-phase of the current three-phase circuit is determined to be missing. In this way, by combining the comparison results of the specific three-phase current magnitudes and the current actual sector switching status, the phase loss status and specific location of the three-phase circuit can be diagnosed. There is no problem of limiting the phase loss threshold current, so there is no need to consider the interference of high-frequency peak current on the detection results. The phase loss status of the three-phase circuit can be effectively detected, ensuring the accuracy of the phase loss detection results and avoiding the occurrence of misjudgment.

[0187] It should be noted that, to ensure the accuracy of the test results, the preset number of tests can be limited to N, where N is an integer greater than or equal to 100. In practical applications, N can take specific values ​​such as 100, 150, 200, 250, and 300, and no specific restriction is imposed here.

[0188] Further, in this embodiment, the first switching state is: the sector corresponding to the space voltage vector switches from the first sector to the sixth sector, and the first preset condition is: among the U-phase current, V-phase current, and W-phase current, the current value of the U-phase current is the largest. Further, the second switching state is: the sector corresponding to the space voltage vector switches from the third sector to the second sector, and the second preset condition is: among the U-phase current, V-phase current, and W-phase current, the current value of the V-phase current is the largest. Further, the third switching state is: the sector corresponding to the space voltage vector switches from the fifth sector to the fourth sector, and the third preset condition is: among the U-phase current, V-phase current, and W-phase current, the current value of the W-phase current is the largest.

[0189] In other words, in the phase loss detection method proposed in this embodiment, if the actual sector switching state is from the first sector to the sixth sector, and the current value of the U-phase current is not the maximum value among the three phases (U-phase current, V-phase current, and W-phase current) after a preset number of consecutive detections, it is determined that the U-phase of the current three-phase circuit is missing; if the actual sector switching state is from the third sector to the second sector, and the current value of the V-phase current is not the maximum value among the three phases (U-phase current, V-phase current, and W-phase current) after a preset number of consecutive detections, it is determined that the V-phase of the current three-phase circuit is missing; if the actual sector switching state is from the fifth sector to the fourth sector, and the current value of the W-phase current is not the maximum value among the three phases (U-phase current, V-phase current, and W-phase current) after a preset number of consecutive detections, it is determined that the W-phase of the current three-phase circuit is missing. In this way, by combining the comparison results of the current values ​​of the U-phase current, V-phase current, and W-phase current, as well as the current actual sector switching status, the phase loss status and specific location of the three-phase circuit can be diagnosed. There is no problem of limiting the phase loss threshold current, so there is no need to consider the interference of high-frequency peak current on the detection results. The phase loss status of the three-phase circuit can be effectively detected, ensuring the accuracy of the phase loss detection results and avoiding the occurrence of misjudgment.

[0190] Example 9, Figure 9 A schematic flowchart of a phase loss detection method according to an embodiment of the present invention is shown as ninth. Specifically, the detection method may include the following steps S902 to S916:

[0191] Step S902: Obtain the current sector code in real time;

[0192] Step S904: Perform phase loss anomaly detection;

[0193] Step S906: Determine if the following condition is not met for N consecutive times: when n = 6 and n0 = 1, Ia > Ib and Ia > Ic. If so, proceed to step S912; otherwise, proceed to step S906.

[0194] Step S908: Determine if the following condition is not met for N consecutive times: when n=2 and n0=3, Ib>Ia and Ib>Ic. If so, proceed to step S914; otherwise, proceed to step S908.

[0195] Step S910: Determine if the following condition is not met for N consecutive times: when n=4 and n0=5, Ic>Ib and Ic>Ia. If so, proceed to step S916; otherwise, proceed to step S910.

[0196] Step S912, determine that phase A is missing;

[0197] Step S914: Determine if phase B is missing;

[0198] Step S916: Determine if phase C is missing.

[0199] The sector code, also known as the sector number, is used to indicate the sector position of the aforementioned space voltage vector in the space vector coordinate system. For example, if the current sector code is 3, it means that the current space voltage vector is located in the third sector in the space vector coordinate system.

[0200] Furthermore, n represents the current sector code (or sector number), while n0 represents the sector code (or sector number) recorded last time.

[0201] Furthermore, Ia represents phase A current, Ib represents phase B current, and Ic represents phase C current. Phase A, phase B, and phase C, as well as phase U, phase V, and phase W, are simply different ways of representing the phases. These two representations correspond to each other: A corresponds to phase U, B corresponds to phase V, and phase C corresponds to phase W. In other words, Ia is equivalent to phase U current Iu, Ib is equivalent to phase V current Iv, and Ic is equivalent to phase W current Iw.

[0202] Therefore, in this embodiment of the invention, when detecting the phase loss state of a three-phase circuit, the current sector code is obtained in real time, that is, the sector position of the current space voltage vector in the space vector coordinate system is obtained in real time. Then, combined with the current sector switching situation and the magnitude comparison relationship between the three-phase phase currents, the abnormal situation of the three-phase circuit is diagnosed.

[0203] Specifically, if the current value of phase A (i.e., phase U) in the three-phase circuit is not at its maximum value when switching from sector 1 to sector 6 for N consecutive times, it is determined that phase A (i.e., phase U) of the current three-phase circuit is missing; if the current value of phase B (i.e., phase V) in the three-phase circuit is not at its maximum value when switching from sector 3 to sector 2 for N consecutive times, it is determined that phase B (i.e., phase V) of the current three-phase circuit is missing; if the current value of phase C (i.e., phase W) in the three-phase circuit is not at its maximum value when switching from sector 5 to sector 4 for N consecutive times, it is determined that phase C (i.e., phase W) of the current three-phase circuit is missing. In this way, by combining the comparison results of the current values ​​between the three phase currents and the current actual sector switching situation, the phase loss status and specific location of the three-phase circuit can be diagnosed. There is no problem of limiting the phase loss threshold current, so there is no need to consider the interference of high-frequency peak current on the detection results. The phase loss status of the three-phase circuit can be effectively detected, ensuring the accuracy of the phase loss detection results and avoiding the occurrence of misjudgment.

[0204] Example 9, Figure 10A structural block diagram of a phase loss detection device 1000 according to an embodiment of the present invention is shown. The detection device includes an acquisition unit 1002 and a processing unit 1004.

[0205] The acquisition unit 1002 is used to acquire the three-phase current of the three-phase circuit and multiple sets of switching signals of the three phase bridge arms;

[0206] Processing unit 1004 is used to determine the space voltage vector corresponding to each group of switching signals;

[0207] The processing unit 1004 is also used to determine the corresponding sector position of each space voltage vector in the space vector coordinate system;

[0208] The processing unit 1004 is also used to perform phase loss detection on the three-phase circuit based on the positions of multiple sectors and the three-phase phase current;

[0209] Each set of switching signals includes three switching signals, three phase bridge arms, and a one-to-one correspondence between the three switching signals.

[0210] The phase loss detection device 1000 provided in this embodiment of the invention is used to detect phase loss in a three-phase circuit. The three-phase circuit includes three phase bridge arms, each corresponding to one phase (U phase, V phase, or W phase). During use, the conduction states of the upper and lower bridge arms of the three phase bridge arms are adjusted to generate corresponding phase currents (U phase current, V phase current, and W phase current). Specifically, each phase bridge arm is equipped with a circuit switch. By controlling the opening or closing of the circuit switch on the phase bridge arm, the conduction states of the upper and lower bridge arms of the corresponding phase bridge arm are controlled.

[0211] The phase loss detection device 1000 provided in this embodiment of the invention acquires the phase currents of phase U, phase V, and phase W in the three-phase circuit at the previous moment through the acquisition unit 1002, that is, it acquires the phase currents of phase U, phase V, and phase W in the three-phase circuit at the current moment through the acquisition unit 1002. Simultaneously, the acquisition unit 1002 also acquires the switching signals of the circuit switches on the three phase bridge arms of the three-phase circuit at the current moment and the previous moment, respectively. The switching signals of the three phase bridge arms at the current moment form one set of switching signals, and the switching signals of the three phase bridge arms at the previous moment form another set of switching signals. Based on this, the processing unit 1004 determines two space voltage vectors according to the two sets of switching signals acquired by the acquisition unit 1002, that is, the processing unit 1004 determines the corresponding space voltage vectors according to the conduction state of the three phase bridge arms. Furthermore, the processing unit 1004 determines the sector position in the space vector coordinate system based on each determined space voltage vector to obtain multiple sector positions. Then, the processing unit 1004 combines the three phase currents detected above and the multiple sector positions to perform phase loss detection on the three-phase circuit.

[0212] Thus, the phase loss detection device 1000 provided in this embodiment of the invention, when performing phase loss detection on a three-phase circuit, combines the current phase current of the three-phase circuit with the sector position of the space voltage vector corresponding to the conduction status of the phase bridge arm in the space vector coordinate system to diagnose whether the three-phase circuit is missing a phase. It uses the relationship between phases and phase currents for fault diagnosis, and there is no problem of limiting the phase loss threshold current. Therefore, there is no need to consider the problem of high-frequency peak current interference. It can effectively detect the phase loss state of the three-phase circuit, ensure the accuracy of the phase loss detection results, and avoid the occurrence of misjudgment problems.

[0213] Among them, the space voltage vector is a type of control vector in the variable frequency speed control system. The space voltage vector is based on the overall generation effect of the three-phase waveform, with the aim of approximating the ideal circular rotating magnetic field trajectory of the motor air gap. It generates a three-phase modulated waveform in one step and controls it by approximating the circle with an inscribed polygon.

[0214] Furthermore, the space voltage vector is related to the conduction state of the three phase bridge arms. Based on the conduction state of the three phase bridge arms, the space voltage vector can include eight basic voltage vectors. Among these eight basic voltage vectors, two are zero vectors and six are non-zero vectors. Based on the six non-zero basic voltage vectors, the space vector coordinate system containing the space voltage vector is divided into six sectors, denoted as the first sector to the sixth sector.

[0215] Furthermore, based on the control principle of space voltage vector, when the switching frequency of the circuit switches on the three phase bridge arms is high, the flux linkage trajectory is close to a quasi-circular shape, thereby achieving motor control. At the non-zero basic voltage vector, a phase peak voltage will appear; that is, when the sector of the space voltage vector in the space vector coordinate system switches, a phase peak voltage will appear, and the magnitude relationship of the phase currents will also show a regular change. Therefore, the phase loss detection device 1000 proposed in this embodiment of the invention uses the relationship between phases and phase currents for fault diagnosis. Specifically, by combining the current phase current of the three-phase circuit and the sector position of the space voltage vector corresponding to the conduction status of the phase bridge arms in the space vector coordinate system, the device diagnoses whether the three-phase circuit is missing a phase, ensuring the accuracy of the phase loss detection results.

[0216] Furthermore, when acquiring multiple sets of switching signals from the three phase bridge arms in the three-phase circuit via the acquisition unit 1002, two sets of switching signals can be acquired within a short time interval at the initial detection moment. The corresponding space voltage vectors are then determined based on these two sets of switching signals, and the corresponding two sector positions are obtained based on the determined space voltage vectors. Phase loss detection is then performed based on the two sector positions and the detected phase current. The determined sector positions can be recorded. During intermediate detection moments, only one set of switching signals from the three phase bridge arms at the current moment needs to be acquired via the acquisition unit 1002, and the corresponding sector position is obtained through the above steps. This is then combined with the most recently recorded historical sector position and the current phase current to perform phase loss detection. This avoids repetitive work, improving phase loss detection efficiency while saving computational resources.

[0217] Therefore, in the phase loss detection device 1000 proposed in this embodiment of the invention, the acquisition unit 1002 acquires the three-phase currents of the three-phase circuit and multiple sets of switching signals of the three phase bridge arms. The processing unit 1004 determines the corresponding space voltage vector based on each set of switching signals, thereby obtaining multiple space voltage vectors. Then, the processing unit 1004 obtains multiple corresponding sector positions based on the multiple space voltage vectors. Finally, the processing unit 1004 performs phase loss detection based on the multiple sector positions and the current three-phase currents. In this way, fault diagnosis is performed using the relationship between phases and phase currents, eliminating the problem of limiting the phase loss threshold current and thus eliminating the need to consider the problem of high-frequency peak current interference. This effectively detects the phase loss state of the three-phase circuit and ensures the accuracy of the phase loss detection results.

[0218] In this embodiment, the processing unit 1004 is further used to: determine the conduction state of the phase bridge arm corresponding to each switch signal; assign a value to each switch signal according to the conduction state; and determine the corresponding space voltage vector according to the value assignment result of each group of switch signals.

[0219] In this embodiment, the processing unit 1004 is further configured to: assign a first flag value to the switch signal when the lower bridge arm of the phase bridge arm is in the open state and the upper bridge arm of the phase bridge arm is in the closed state; and assign a second flag value to the switch signal when the lower bridge arm of the phase bridge arm is in the closed state and the upper bridge arm of the phase bridge arm is in the open state; wherein the first flag value and the second flag value are both binary values.

[0220] Specifically, the first flag value is 1, and the second flag value is 0.

[0221] Additionally, it should be noted that during the switching process of the phase bridge arm conduction state, that is, during the change of the switching signal, the switching signal is assigned a value and marked according to the conduction state before the phase bridge arm conduction state switching.

[0222] In this embodiment, the processing unit 1004 is further configured to: sort the assignment marker values ​​of each switch signal according to a preset order to obtain the corresponding binary code; and determine the space voltage vector according to the binary code.

[0223] Specifically, the three switch signals in each group correspond one-to-one with the three phase bridge arms, and the assignment mark values ​​of the three switch signals in each group are sorted from left to right in the order of U phase, V phase, and W phase.

[0224] In this embodiment, the processing unit 1004 is further used to: determine the sector position of each space voltage vector in multiple sectors according to a preset correspondence.

[0225] In this embodiment, the processing unit 1004 is further used to: determine the current sector switching state of the space voltage vector in the space vector coordinate system based on multiple sector positions; and, when the current moment is a sector switching moment, perform phase loss detection on the three-phase circuit based on the three-phase phase current and the sector switching state.

[0226] In this embodiment, the processing unit 1004 is further used to: compare the magnitudes of the three-phase currents when the current moment is a sector switching moment; and perform phase loss detection on the three-phase circuit based on the sector switching state and the comparison results of the phase current magnitudes.

[0227] In this embodiment, the processing unit 1004 is further configured to: determine phase U is missing if the comparison result does not meet the first preset condition for a preset number of consecutive times when the sector switching state is in the first switching state; determine phase V is missing if the comparison result does not meet the second preset condition for a preset number of consecutive times when the sector switching state is in the second switching state; and determine phase W is missing if the comparison result does not meet the third preset condition for a preset number of consecutive times when the sector switching state is in the third switching state.

[0228] To ensure the accuracy of the test results, the preset number of tests can be limited to N, where N is an integer greater than or equal to 100. In practical applications, N can take specific values ​​such as 100, 150, 200, 250, and 300, and no specific restriction is imposed here.

[0229] In this embodiment, further, the first switching state is: the sector corresponding to the space voltage vector switches from the first sector to the sixth sector, and the first preset condition is: among the U-phase current, V-phase current, and W-phase current, the current value of the U-phase current is the largest. Further, the second switching state is: the sector corresponding to the space voltage vector switches from the third sector to the second sector, and the second preset condition is: among the U-phase current, V-phase current, and W-phase current, the current value of the V-phase current is the largest. Further, the third switching state is: the sector corresponding to the space voltage vector switches from the fifth sector to the fourth sector, and the third preset condition is: among the U-phase current, V-phase current, and W-phase current, the current value of the W-phase current is the largest.

[0230] Example 11, Figure 11 A structural block diagram of a frequency converter 1100 provided in an embodiment of the present invention is shown. The frequency converter 1100 includes:

[0231] Memory 1102, which stores programs or instructions;

[0232] The processor 1104, when executing the above program or instructions, implements the steps of the phase loss detection method as described in any of the above embodiments.

[0233] The inverter 1100 provided in this embodiment includes a memory 1102 and a processor 1104. When the program or instructions in the memory 1102 are executed by the processor 1104, they implement the steps of the phase loss detection method as described in any of the above embodiments. Therefore, the inverter 1100 has all the beneficial effects of the phase loss detection method in any of the above embodiments, which will not be repeated here.

[0234] Specifically, the memory 1102 and the processor 1104 can be connected via a bus or other means. The processor 1104 may include one or more processing units, and the processor 1104 may be a chip such as a central processing unit (CPU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), or a field-programmable gate array (FPGA).

[0235] Example 12, Figure 12 A structural block diagram of a frequency converter 1200 provided in an embodiment of the present invention is shown, wherein the frequency converter 1200 includes: the phase loss detection device 1000 in the above embodiment.

[0236] The frequency converter 1200 provided in this embodiment includes the phase loss detection device 1000 in the above embodiments. Therefore, the frequency converter 1200 has all the beneficial effects of the phase loss detection device 1000 in any of the above embodiments, which will not be repeated here.

[0237] Example 13, Figure 13 A structural block diagram of a motor 1300 provided in an embodiment of the present invention is shown. The motor 1300 includes the frequency converter 1100 described in the above embodiment.

[0238] The motor 1300 provided in this embodiment includes the frequency converter 1100 in the above embodiments. Therefore, the motor 1300 possesses all the technical effects of the frequency converter 1100 in the above embodiments, which will not be repeated here.

[0239] Example 14, Figure 14 A structural block diagram of a motor 1400 provided in an embodiment of the present invention is shown. The motor 1400 includes the frequency converter 1200 described in the above embodiment.

[0240] The motor 1400 provided in this embodiment includes the frequency converter 1200 in the above embodiment. Therefore, the motor 1400 possesses all the technical effects of the frequency converter 1200 in the above embodiment, which will not be repeated here.

[0241] Example 15, 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 described in the above embodiment.

[0242] The electrical device 1500 provided in this embodiment 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, which will not be repeated here.

[0243] Example 16, Figure 16 A structural block diagram of an electrical device 1600 provided in an embodiment of the present invention is shown. The electrical device 1600 includes the motor 1400 described in the above embodiment.

[0244] The electrical device 1600 provided in this embodiment includes the motor 1400 in the above embodiments. Therefore, the electrical device 1600 possesses all the technical effects of the motor 1400 in the above embodiments, which will not be repeated here.

[0245] It should be noted that the electrical equipment proposed in the embodiments of the present invention includes, but is not limited to, the following products: electric fans, refrigerators, and washing machines, which will not be listed here one by one.

[0246] Example 17, an embodiment of the seventh aspect of the present invention, provides a readable storage medium. A program or instructions are stored thereon, which, when executed by a processor, implement the steps of the phase loss detection method as described in any of the above embodiments.

[0247] 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 phase loss detection method as described in any of the above embodiments. Therefore, this readable storage medium possesses all the beneficial effects of the phase loss detection method in any of the above embodiments, which will not be elaborated further here.

[0248] 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.

[0249] 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.

[0250] 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.

[0251] 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.

[0252] 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. A phase deficiency detection method, characterized by, include: The three-phase current and multiple sets of switching signals of the three phase bridge arms of the three-phase circuit are obtained. Each set of switching signals includes three switching signals, and the three switching signals correspond one-to-one with the three phase bridge arms. Determine the space voltage vector corresponding to each group of the switching signals; Determine the corresponding sector position of each of the space voltage vectors in the space vector coordinate system; The three-phase circuit is subjected to phase loss detection based on the three-phase phase current and the determined sector positions; The step of performing phase loss detection on the three-phase circuit based on the three-phase phase currents and the determined sector positions specifically includes: The current sector switching state of the space voltage vector in the space vector coordinate system is determined based on the multiple sector positions; Based on the current time being the sector switching time, the three-phase circuit is subjected to phase loss detection according to the sector switching status and the three-phase current.

2. The phase deficiency detection method according to claim 1, characterized by Determining the space voltage vector corresponding to each group of switching signals specifically includes: Determine the conduction state of the phase bridge arm corresponding to each of the aforementioned switch signals; Each of the switch signals is assigned a value and marked according to the conduction state; The corresponding space voltage vector is determined based on the assignment and marking results of each group of switch signals.

3. The phase deficiency detection method according to claim 2, characterized by, The step of assigning a value to each of the switching signals according to the conduction state specifically includes: Based on the fact that the upper bridge arm of the phase bridge arm is conducting and the lower bridge arm of the phase bridge arm is disconnected, the switch signal is assigned and marked as the first flag value; Based on the fact that the upper bridge arm of the phase bridge arm is disconnected and the lower bridge arm of the phase bridge arm is connected, the switch signal is assigned a second flag value; Wherein, the first flag value and the second flag value are binary values.

4. The phase deficiency detection method according to claim 3, characterized by, The step of determining the corresponding space voltage vector based on the assignment and marking results of each group of switching signals specifically includes: The assigned marker values ​​of each switch signal are sorted according to a preset order to obtain the corresponding binary code; The binary code is determined as the space voltage vector.

5. The phase deficiency detection method according to claim 4, characterized by The spatial vector coordinate system includes multiple sectors, and determining the corresponding sector position of each spatial voltage vector in the spatial vector coordinate system specifically includes: The corresponding sector of each space voltage vector in the plurality of sectors is determined according to a preset correspondence.

6. The phase failure detection method of claim 1, wherein The step of performing phase loss detection on the three-phase circuit based on the sector switching status and the three-phase phase current specifically includes: Compare the magnitudes of the three-phase currents; The three-phase circuit is subjected to phase loss detection based on the comparison results and the sector switching status.

7. The phase failure detection method according to claim 6, characterized by, The step of performing phase loss detection on the three-phase circuit based on the comparison result and the sector switching status specifically includes: Based on the fact that the sector switching state is the first switching state, and the fact that the comparison result does not meet the first preset condition for a consecutive preset number of times, it is determined that the U phase of the three-phase circuit is missing. Based on the fact that the sector switching state is the second switching state, and the fact that the comparison result does not meet the second preset condition for a consecutive preset number of times, it is determined that the V phase of the three-phase circuit is missing. Based on the fact that the sector switching state is the third switching state, and the fact that the comparison result does not meet the third preset condition for a consecutive preset number of times, it is determined that the W phase of the three-phase circuit is missing.

8. The phase loss detection method according to claim 7, characterized in that, The first switching state is: the sector position of the space voltage vector in the space vector coordinate system is switched from the first sector to the sixth sector; The first preset condition is: the U-phase current is greater than the V-phase current, and the U-phase current is greater than the W-phase current; The second switching state is: the sector position of the space voltage vector in the space vector coordinate system is switched from the third sector to the second sector; The second preset condition is: the V-phase current is greater than the U-phase current, and the V-phase current is greater than the W-phase current; The third switching state is: the sector position of the space voltage vector in the space vector coordinate system is switched from the fifth sector to the fourth sector; The third preset condition is: the W-phase current is greater than the U-phase current, and the W-phase current is greater than the V-phase current.

9. A phase deficiency detection device, characterized by include: The acquisition unit is used to acquire the three-phase current and multiple sets of switching signals of the three phase bridge arms of the three-phase circuit. Each set of switching signals includes three switching signals, and the three switching signals correspond one-to-one with the three phase bridge arms. The processing unit is used to determine the space voltage vector corresponding to each group of the switching signals; The processing unit is also used to determine the corresponding sector position of each space voltage vector in the space vector coordinate system; The processing unit is also configured to perform phase loss detection on the three-phase circuit based on the three-phase phase current and the determined positions of the plurality of sectors; The step of performing phase loss detection on the three-phase circuit based on the three-phase phase currents and the determined sector positions specifically includes: The current sector switching state of the space voltage vector in the space vector coordinate system is determined based on the multiple sector positions; Based on the current time being the sector switching time, the three-phase circuit is subjected to phase loss detection according to the sector switching status and the three-phase current.

10. A frequency converter, characterized in that include: Memory, which stores programs or instructions; A processor that, when executing the program or instructions, implements the steps of the phase loss detection method as described in any one of claims 1 to 8.

11. A frequency converter, characterized in that include: The phase loss detection device as described in claim 9.

12. An electric machine characterized by include: The frequency converter as described in claim 10; or The frequency converter as described in claim 11.

13. An electrical appliance characterized by include: The motor as described in claim 12.

14. A readable storage medium, on which a program or instructions are stored, characterized in that, When the program or instructions are executed by the processor, they implement the steps of the phase loss detection method as described in any one of claims 1 to 8.

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