JP5871638B2 - Inverter device - Google Patents

Description

  Embodiments described herein relate generally to an inverter device.

  The inverter device usually has various trip functions such as overcurrent trip, overvoltage trip, and overheat trip. Of these, overcurrent trip is a gate signal supplied to the inverter circuit to measure the output current of the inverter device and prevent the inverter device from failing if the output current suddenly increases due to a short circuit of the motor, etc. It is a function to stop.

  However, the output current does not exceed the overcurrent protection level when the load on the inverter device is only slightly increased due to deterioration of the motor or load machine (for example, insufficient motor grease or wear of machine parts). Driving will continue. This may lead to a motor failure, and a function is required to issue a warning by detecting deterioration of the motor or load machine.

  As the above-mentioned countermeasure, an inverter device has been developed that measures an output current and an output frequency, and determines that a motor abnormality has occurred when the value of the output current with respect to the output frequency exceeds a reference. In addition, an inverter device that detects a motor abnormality by frequency analysis of any one of a position command, a motor position, a speed command, a motor speed, torque, and mechanical vibration has been developed.

  In such an inverter device, it is usually necessary to keep the output power applied to the motor at a predetermined value for stable operation of the motor. For example, when the input voltage to the inverter device decreases, it is necessary to increase the output current. Conversely, when the input voltage to the inverter device increases, it is necessary to decrease the output current. For this reason, the output current may fluctuate according to the change of the input voltage.

JP 2007-288829 A JP 2010-166686 A

  In the inverter device that detects a motor abnormality using the output current described above, the output current fluctuates due to a change in the input voltage. Therefore, it is distinguished whether the fluctuation in the output current is due to a motor abnormality or a change in the input voltage. This is impossible and the detection accuracy of the motor abnormality is reduced.

  In addition, the inverter device that detects the motor abnormality by performing the frequency analysis described above requires a processing time for the frequency analysis, and a high-performance processing device is required to shorten the processing time, resulting in an increase in cost. Resulting in.

  The problem to be solved by the present invention is to provide an inverter device that can accurately detect a motor abnormality at low cost.

An inverter device according to an embodiment includes an inverter unit that converts a DC voltage into an AC voltage and outputs the voltage to a motor, a voltage detection circuit that detects an output voltage for the motor, a current detection circuit that detects an output current for the motor, and a voltage A power calculation unit that calculates output power from the output voltage detected by the detection circuit and the output current detected by the current detection circuit, and an abnormality detection unit that detects a motor abnormality from a change in output power calculated by the power calculation unit And a speed adjustment unit that controls the inverter unit to keep the rotation speed of the motor constant. When the motor continues to rotate at a constant speed, the power calculation unit and the motor output power per unit time in the initial operation of the motor The output power per unit time after the initial operation of the motor is calculated. It is determined whether the ratio between the output power reference value, which is the output power of time, and the output power per unit time calculated after the initial operation of the motor calculated by the power calculation unit is within an allowable range. When it is determined that the value is not within the allowable range, a motor abnormality is detected .

It is a figure which shows schematic structure of the inverter apparatus which concerns on one Embodiment. It is a flowchart which shows the flow of the motor abnormality detection process which detects motor abnormality from the change of the output electric power per unit time. It is explanatory drawing for demonstrating the motor speed control (frequency control) which concerns on the motor abnormality detection process shown in FIG. It is a flowchart which shows the flow of the motor abnormality detection process which detects a motor abnormality from the change of the output electric power for one speed pattern. It is explanatory drawing for demonstrating the motor speed control (frequency control) which concerns on the motor abnormality detection process shown in FIG. It is a flowchart which shows the flow of the motor abnormality detection process which detects motor abnormality from the change of the output electric power for every rotational speed in one speed pattern. It is explanatory drawing for demonstrating the motor speed control (frequency control) which concerns on the motor abnormality detection process shown in FIG.

  An embodiment will be described with reference to the drawings.

  As shown in FIG. 1, the inverter device 1 according to the present embodiment displays a main circuit 2, a control unit 3 that controls the main circuit 2, a storage unit 4 that stores various information, and numerical values, characters, and the like. And a display unit 5 to be operated and an operation unit 6 to be input by a user.

  The main circuit 2 rectifies the AC voltage supplied from the three-phase AC power supply A1 and outputs the rectified voltage between the power supply lines 11 and 12, and the smoothing capacitor 14 connected between the power supply lines 11 and 12. From the inverter unit 15 that converts the DC voltage between the power supply lines 11 and 12 into an AC voltage and supplies it to the motor A2, the voltage detection circuit 16 that detects the DC voltage on the input side of the inverter unit 15, and the inverter unit 15 And a plurality of current detection circuits 17 for detecting an output current output to the motor A2.

  The converter unit 13 is configured by connecting a diode 13a to a three-phase bridge. The converter unit 13 functions as a rectifying unit. Further, the inverter unit 15 is configured by connecting switching elements 15a such as IGBTs (Insulated Gate Bipolar Transistors), for example, in a three-phase bridge, and by connecting freewheeling diodes 15b in parallel to the switching elements 15a.

  The voltage detection circuit 16 is provided to detect a DC voltage between the power supply lines 11 and 12 and is electrically connected to the control unit 3. Each current detection circuit 17 is provided to detect an output current for each of the three phases, and is electrically connected to the control unit 3.

  The voltage detection circuit 16 described above is provided so as to be able to detect the output voltage of the inverter device 1, that is, to detect a DC voltage between the power supply lines 11, 12. The AC voltage on the output side of the inverter unit 15 may be detected.

  Further, the current detection circuit 17 described above is provided so as to be able to detect the output current of the inverter device 1, that is, to detect the output current for each of the three phases, but is not limited thereto. Of the three phases, the output current of only two or one phase may be detected, or may be detected by connecting a current detection resistor in series with each IGBT.

  The control unit 3 generates a gate signal (gate drive signal) for the switching element 15 a and supplies the generated gate signal to the inverter unit 15 to control the inverter unit 15. The control unit 3 includes a CPU (Central Processing Unit) capable of executing various calculations related to motor control represented by V / f (voltage / frequency) constant control at high speed, a timer capable of measuring time, and the like.

  In particular, the control unit 3 includes a speed adjustment unit 3a that adjusts the rotation speed (operation frequency) of the motor A2 in motor control, a DC voltage detected by the voltage detection circuit 16, and an output current detected by the current detection circuit 17. And an abnormality detection unit 3c that detects an abnormality of the motor A2 in accordance with a change in the output power calculated by the power calculation unit 3b.

  These speed adjustment unit 3a, power calculation unit 3b, and abnormality detection unit 3c may be configured by hardware such as an electric circuit, or may be configured by software such as a program that executes these functions. . Moreover, you may comprise by the combination of both hardware and software.

  The memory | storage part 4 memorize | stores various information, such as various programs and various data (For example, various setting data, the past trip history, accumulated operation time). As the storage unit 4, for example, a ROM (Read Only Memory), a RAM (Random Access Memory), a flash memory, or the like can be used.

  The display unit 5 displays various information such as the operating frequency, output current, output voltage, trip code, and the like. As the display unit 5, for example, an LED (Light Emitting Diode) panel, an LCD (Liquid Crystal Display) panel, or the like can be used.

  The operation unit 6 is an input unit that receives an input operation from a user, and receives various input operations such as various settings such as a maximum frequency, acceleration time, and deceleration time, and selection of a speed pattern. As the operation unit 6, for example, an input device such as a button (key) can be used.

  In such an inverter device 1, the three-phase AC voltage is converted into a DC voltage by the converter unit 13 and smoothed by the capacitor 14. The smoothed DC voltage is converted into an arbitrary three-phase AC voltage by the inverter unit 15 and output to the motor A2, and the motor A2 is driven.

  At this time, the DC voltage on the input side of the inverter unit 15 is detected by the voltage detection circuit 16, and the output current of each phase on the output side of the inverter unit 15 is detected by each current detection circuit 17. Entered. The control unit 3 calculates output power from each input value, and detects motor abnormality from the calculated change in output power.

  Next, the motor abnormality detection process for detecting the above-described motor abnormality will be described in detail. First, a motor abnormality detection process for detecting a motor abnormality from a change in output power per unit time will be described with reference to FIGS.

As shown in FIG. 2, the power calculation unit 3b calculates the output power _Pn per unit time Δt from the input DC voltage and output current (step S1), and then the abnormality detection unit 3c performs the current operation. It is determined whether or not is the first operation (step S2).

Here, regarding the output power P _n , as shown in FIG. 3, n is the number of operations (n = 1, 2, 3,...) That increases by one for each unit time Δt. Accordingly, the output power P _n is sequentially calculated as P ₁ , P ₂ , P ₃ ,... As n increases.

In FIG. 3, the frequency (operating frequency) is constant at F1, and is switched to F2 in the course of time (F ₁ <F ₂ ) and remains constant. This frequency and the rotational speed of the motor A2 are in a proportional relationship. Such a frequency is preset in the storage unit 4 by a user input operation on the operation unit 6. The speed adjustment unit 3a controls the inverter unit 15 based on the set frequency and adjusts the rotation speed of the motor A2 to be constant.

Returning to Figure 2, in step S2, the current operation is the first operation (n = 1) to the determining that (YES in step S2), the reference value the output power _{P 1} (output power reference value) storage unit as _{P 0} 4 (step S3), and thereafter n = n + 1 is calculated (step S4), and the processing is repeated from step S1.

  On the other hand, when it is determined in step S2 that the current operation is not the first operation (n ≠ 1), that is, after the second operation (NO in step S2), the rotation speed of motor A2 is changed in the current operation (operation frequency change). Is determined (step S5).

If it is determined in step S5 that there is no change in the rotational speed of the motor A2 (NO in step S5), it is determined whether or not the output power fluctuation rate α _n is within an allowable range of 0.9 ≦ α _n ≦ 1.1. (Step S6). The output power fluctuation rate α _n is obtained by α _n = P _n / P ₀ (n = 2, 3,...).

  Note that the lower limit value 0.9 and the upper limit value 1.1 of the allowable range described above are cases where the allowable output power fluctuation rate is ± 10% (example), and the user operates the operation unit 6 with an input operation. By doing so, it is possible to arbitrarily set the allowable range according to the conditions.

If it is determined in step S6 that the output power fluctuation rate α _n is not within the allowable range of 0.9 ≦ α _n ≦ 1.1 (NO in step S6), the occurrence of an abnormality in the motor A2 is detected, and the display unit 5 A warning (alarm) is displayed (step S7).

  As a warning, for example, when an alphanumeric character called a trip code (which alphanumeric character indicates a motor abnormality is predetermined) is displayed, or when the display unit 5 is an LCD panel, For example, it is possible to display characters such as “motor abnormality”.

On the other hand, if it is determined in step S6 that the output power fluctuation rate α _n is within the allowable range of 0.9 ≦ α _n ≦ 1.1 (YES in step S6), n = n + 1 is calculated (step S4). ), The process is repeated from step S1.

If it is determined in step S5 that there is a change in the rotational speed of motor A2, that is, there is a change in operating frequency (YES in step S5), the output power _Pn immediately after the change and the output power fluctuation rate α _n-1 immediately before the change are changed. The subsequent reference value P ₀ is calculated as P ₀ = P _n / α _n−1 and stored in the storage unit 4 (step S8). Thereafter, n = n + 1 is calculated (step S4), and the processing is repeated from step S1.

In such motor abnormality detection processing, the output power P _n per unit time Δt is calculated from the input DC voltage and output current, and stored as a reference value P ₀ = P ₁ at the time of initial operation (n = 1). (See FIG. 3). From the second time on, it is determined whether or not the output power fluctuation rate α _n is within an allowable range of 0.9 ≦ α _n ≦ 1.1. When the output power fluctuation rate α _n is not within the above-described allowable range, it is determined that the motor A2 that is the load of the inverter is abnormal, and the motor abnormality is detected. In response to this, the display unit 5 displays, for example, alphanumeric characters of a trip code or characters “motor abnormality” as a warning.

Here, the output power P _n is kept at a predetermined value for the stable operation of the motor A2. For example, even when the output current fluctuates due to a change in the input voltage to the inverter device 1, the output power P _n is maintained constant without fluctuating. For this reason, the fluctuation | variation of output electric power _Pn becomes a thing according to abnormality of motor A2. Since the abnormality of the motor A2 is detected from the fluctuation of the output power _Pn , the abnormality of the motor A2 can be accurately detected. Further, since a warning indicating that fact is notified to the user in accordance with the occurrence of the abnormality in the motor A2, the user can quickly grasp the occurrence of the motor abnormality.

When the operating frequency (the rotational speed of the motor A2) is changed (see FIG. 3), the reference value P after the change from the output power P _n immediately after the change and the output power fluctuation rate α _n−1 immediately before the change. ₀ is calculated as P ₀ = P _n / α _n−1 , stored in the storage unit 4, and used as a new reference value. Accordingly, even when the driving frequency is changed, since the reference value P ₀ in consideration of the deterioration degree of the motor A2 until it is reset, it is possible to realize a higher accuracy motor abnormality detection.

  Next, a motor abnormality detection process for detecting a motor abnormality from a change in output power for one speed pattern will be described with reference to FIGS.

As shown in FIG. 4, the power calculation unit 3b calculates the output power P _n for one speed pattern from the input DC voltage and output current (step S11), and then the abnormality detection unit 3c It is determined whether or not the operation is an initial operation (step S12).

Here, regarding the output power P _n , as shown in FIG. 5, n is a unit time Δt, that is, the number of times of operation that increases for each speed pattern (operation frequency pattern) (n = 1, 2, 3,... ). Accordingly, the output power P _n is sequentially calculated as P ₁ , P ₂ , P ₃ ,... As n increases.

In FIG. 5, the same speed pattern (operating frequency pattern) is repeated every unit time Δt. In one speed pattern, the frequency is switched from F ₁ to F ₃ and is switched from F ₃ to F ₂ , and the frequency is switched stepwise (F ₁ <F ₂ <F ₃ ). This frequency and the rotational speed of the motor A2 are in a proportional relationship. Such a speed pattern is preset in the storage unit 4 by a user input operation on the operation unit 6. The speed adjustment unit 3a controls the inverter unit 15 based on the same speed pattern every unit time Δt to adjust the rotation speed of the motor A2.

Returning to FIG. 4, in step S12, it is first operated the current operation (n = 1) to the determining that (YES in step S12), the reference value the output power _{P 1} (output power reference value) storage unit as _{P 0} 4 (step S13), and then n = n + 1 is calculated (step S14), and the processing is repeated from step S11.

  On the other hand, if it is determined in step S12 that the current operation is not the first operation (n ≠ 1), that is, the second or subsequent operation (NO in step S12), whether or not there is a speed pattern change (operation frequency pattern change) in the current operation Is determined (step S15).

If it is determined in step S15 that there is no speed pattern change (NO in step S15), it is determined whether or not the output power fluctuation rate α _n is within an allowable range of 0.9 ≦ α _n ≦ 1.1 (step S15). S16). The output power fluctuation rate α _n is obtained by α _n = P _n / P ₀ (n = 2, 3,...).

  Here, similarly to the above, the lower limit value 0.9 and the upper limit value 1.1 of the allowable range described above are cases where the allowable output power fluctuation rate is ± 10% (example), and the user By inputting the operation unit 6, it is possible to arbitrarily set the allowable range according to the conditions.

If it is determined in step S16 that the output power fluctuation rate α _n is not within the allowable range of 0.9 ≦ α _n ≦ 1.1 (NO in step S16), the occurrence of an abnormality in the motor A2 is detected, and the display unit 5 A warning (alarm) is displayed (step S17).

  In this case as well, as described above, as a warning, for example, an alphanumeric character called a trip code (which alphanumeric character indicates a motor abnormality is determined in advance) or the display unit 5 is displayed on the LCD In the case of a panel, it is possible to display, for example, characters such as “motor abnormality”.

On the other hand, when it is determined in step S16 that the output power fluctuation rate α _n is within the allowable range of 0.9 ≦ α _n ≦ 1.1 (YES in step S16), n = n + 1 is calculated (step S14). ), The process is repeated from step S11.

If it is determined in step S15 that there is a speed pattern change, that is, an operation frequency pattern change (YES in step S15), the output power P _n immediately after the change and the output power fluctuation rate α _n−1 immediately before the change are changed. The reference value P ₀ is calculated as P ₀ = P _n / α _n−1 and stored in the storage unit 4 (step S18). Thereafter, n = n + 1 is calculated (step S14), and the processing is repeated from step S11.

In such motor abnormality detection processing, the output power P _n for one speed pattern is calculated from the input DC voltage and output current, and the reference value P ₀ = P ₁ is set at the initial operation (n = 1). Stored (see FIG. 5). From the second time on, it is determined whether or not the output power fluctuation rate α _n is within an allowable range of 0.9 ≦ α _n ≦ 1.1. When the output power fluctuation rate α _n is not within the above-described allowable range, it is determined that the motor A2 that is the load of the inverter is abnormal, and the motor abnormality is detected. In response to this, the display unit 5 displays, for example, alphanumeric characters of a trip code or characters “motor abnormality” as a warning.

Here, the output power P _n is kept at a predetermined value for the stable operation of the motor A2. For example, even when the output current fluctuates due to a change in the input voltage to the inverter device 1, the output power P _n is maintained constant without fluctuating. For this reason, the fluctuation | variation of output electric power _Pn becomes a thing according to abnormality of motor A2. Since the abnormality of the motor A2 is detected from the fluctuation of the output power _Pn , the abnormality of the motor A2 can be accurately detected. Further, since a warning indicating that fact is notified to the user in accordance with the occurrence of the abnormality in the motor A2, the user can quickly grasp the occurrence of the motor abnormality.

When the speed pattern (operation frequency pattern) is changed (see FIG. 5), the changed reference value P ₀ is obtained from the output power P _n immediately after the change and the output power fluctuation rate α _n−1 immediately before the change. It is calculated as P ₀ = P _n / α _n−1 , stored in the storage unit 4, and used as a new reference value. Accordingly, even when the speed pattern is changed, since the reference value P ₀ in consideration of the deterioration degree of the motor A2 until it is reset, it is possible to realize a higher accuracy motor abnormality detection.

  Next, a motor abnormality detection process for detecting a motor abnormality from a change in output power for each rotation speed within one speed pattern will be described with reference to FIGS.

As shown in FIG. 6, the power calculator 3b calculates the output power P _nm for each rotational speed in one speed pattern from the input DC voltage and output current (step S21), and then the abnormality detector 3c. Determines whether the current operation is the first operation (step S22).

Here, regarding the output power P _nm , as shown in FIG. 7, n is the unit time Δt, that is, the number of times of operation increasing for each speed pattern (operation frequency pattern) (n = 1, 2, 3,... M is the number of constant speeds in one speed pattern (m = 1, 2, 3). Therefore, as n and m increase, the output power P _nm is sequentially increased to P ₁₁ , P ₁₂ , P ₁₃ , n = 2, and P ₂₁ , P ₂₂ , P ₂₃ ,. Will be calculated.

In FIG. 7, the same speed pattern (operating frequency pattern) is repeated every unit time Δt. In one speed pattern, the frequency is switched from F ₁ to F ₃ and is switched from F ₃ to F ₂ , and the frequency is switched stepwise (F ₁ <F ₂ <F ₃ ). At this time, the time frequency is _{F 1} is _{T 1,} the time-frequency is _{F 2} is _{T 2,} the time frequency is _{F 3} is _{T 3.} This frequency and the rotational speed of the motor A2 are in a proportional relationship. Such a speed pattern is preset in the storage unit 4 by a user input operation on the operation unit 6. The speed adjustment unit 3a controls the inverter unit 15 based on the same speed pattern every unit time Δt to adjust the rotation speed of the motor A2.

Returning to FIG. 6, when it is determined in step S22 that the current operation is the first operation (n = 1) (YES in step S22), the output power P _1m is stored as a reference value (output power reference value) P _0m. 4 (step S23), and then n = n + 1 is calculated (step S24), and the processing is repeated from step S21. Note that m is a natural number (a positive integer), and m = 1, 2, 3 in FIG.

  On the other hand, if it is determined in step S22 that the current operation is not the first operation (n ≠ 1), that is, the second or subsequent operation (NO in step S22), whether or not there is a speed pattern change (operation frequency pattern change) in the current operation. Is determined (step S25).

If it is determined in step S25 that there is no speed pattern change (NO in step S25), it is determined whether or not the output power fluctuation rate α _nm is within an allowable range of 0.9 ≦ α _nm ≦ 1.1 (step S25). S26). The output power fluctuation rate α _nm is obtained by α _nm = P _nm / P _0m (n = 2, 3,...).

  Here, similarly to the above, the lower limit value 0.9 and the upper limit value 1.1 of the allowable range described above are cases where the allowable output power fluctuation rate is ± 10% (example), and the user By inputting the operation unit 6, it is possible to arbitrarily set the allowable range according to the conditions.

If it is determined in step S26 that the output power fluctuation rate α _nm is not within the allowable range of 0.9 ≦ α _nm ≦ 1.1 (NO in step S26), the occurrence of an abnormality in the motor A2 is detected, and the display unit 5 A warning (alarm) is displayed (step S27).

  In this case as well, as described above, as a warning, for example, an alphanumeric character called a trip code (which alphanumeric character indicates a motor abnormality is determined in advance) or the display unit 5 is displayed on the LCD In the case of a panel, it is possible to display, for example, characters such as “motor abnormality”.

On the other hand, if it is determined in step S26 that the output power fluctuation rate α _nm is within the allowable range of 0.9 ≦ α _nm ≦ 1.1 (YES in step S26), n = n + 1 is calculated (step S24). ), The process is repeated from step S21.

If it is determined in step S25 that there is a speed pattern change, that is, an operation frequency pattern change (YES in step S25), the output power P _nm immediately after the change and the output power fluctuation rate α _{(n−1) m} immediately before the change are determined. The changed reference value P _0m is calculated as P _0m = P _nm / α _{(n−1) m} and stored in the storage unit 4 (step S28). Thereafter, n = n + 1 is calculated (step S24), and the processing is repeated from step S21.

In such motor abnormality detection processing, the output power P _nm for each rotation speed (frequency in the operation frequency pattern) in one speed pattern is calculated from the input DC voltage and output current, and the initial operation (n = 1) is stored as a reference value P _0m = P _1m (see FIG. 7, m = 1, 2, 3). That is, output powers P ₁₁ , P _12, P _{13 at} the respective frequencies F ₁ , F ₃ , F ₂ (T ₁ , T ₂ , T ₃ ) are calculated, and the reference values P ₀₁ , P ₀₂ , P ₁₃ are respectively calculated. It is stored as ₀₃ . From the second time on, it is determined whether or not the output power fluctuation rate α _nm is within an allowable range of 0.9 ≦ α _nm ≦ 1.1. When the output power fluctuation rate α _nm is not within the above-described allowable range, it is determined that the motor A2 that is the load of the inverter is abnormal, and the motor abnormality is detected. In response to this, the display unit 5 displays, for example, alphanumeric characters of a trip code or characters “motor abnormality” as a warning.

Here, the output power P _nm is maintained at a predetermined value for the stable operation of the motor A2. For example, even when the output current fluctuates due to a change in the input voltage to the inverter device 1, the output power P _nm is maintained constant without fluctuating. For this reason, the fluctuation _| variation of output electric power _Pnm respond | corresponds to abnormality of motor A2. Since detecting the abnormality of the motor A2 from changes in the output power P _nm, it is possible to accurately detect the abnormality of the motor A2. Further, since a warning indicating that fact is notified to the user in accordance with the occurrence of the abnormality in the motor A2, the user can quickly grasp the occurrence of the motor abnormality.

When the speed pattern (operation frequency pattern) is changed (see FIG. 7), the reference value after change from the output power P _nm immediately after the change and the output power fluctuation rate α _{(n−1) m} immediately before the change. P _0m is calculated as P _0m = P _nm / α _{(n−1) m} , stored in the storage unit 4, and used as a new reference value. Accordingly, even when the speed pattern is changed, since the reference value P ₀ in consideration of the deterioration degree of the motor A2 until it is reset, it is possible to realize a higher accuracy motor abnormality detection.

Here, as shown in FIG. 7, when the speed pattern is changed, the reference value P ₀₂ of the output power in the changed section T ₂ is the output power fluctuation rate α _{(n−1) 2} before the change. _{= P (n-1) 2} / P 02 and immediately after the change from the output power _{P n2 P 02 = P n2 /} α (n-1) is calculated as _2, is stored as a new reference value. At this time, with respect to the reference value P ₀₁ and the reference value P ₀₃ , no recalculation is performed because there is no speed change. Thereby, it is possible to shorten the calculation time related to the resetting of the reference value P _0m .

  Of the three motor abnormality detection processes described above, which motor abnormality detection process is executed is set in advance by a user input operation on the operation unit 6, but is not limited thereto. One motor abnormality detection process may be automatically selected and executed from the three motor abnormality detection processes according to the rotation speed control of A2.

  For example, when the speed pattern is not set and only the predetermined rotation speed is set, the first motor abnormality detection process (see FIG. 2) is automatically selected from the three motor abnormality detection processes. And execute. When a speed pattern is set, the second motor abnormality detection process (see FIG. 4) or the third motor abnormality detection process (see FIG. 6) is automatically selected from the three motor abnormality detection processes. And run.

  As described above, according to the above-described embodiment, the output voltage and output current for the motor A2 are detected to calculate the output power, and the abnormality of the motor A2 is detected according to the calculated change in the output power. As a result, the output voltage is used in addition to the output current, and the abnormality of the motor A2 is detected from the change in the output power. Therefore, it is only necessary to calculate the output power that fluctuates in accordance with the abnormality of the motor A2, and it is possible to detect the abnormality of the motor A2 with high accuracy without requiring a high-performance processing device. Can be performed at low cost and with high accuracy.

  When the motor A2 continues to rotate at a constant speed, the output power per unit time in the initial operation of the motor A2 and the output power per unit time after the initial operation of the motor A2 are calculated, and the unit time in the initial operation of the motor A2 is calculated. It is determined whether or not the ratio between the output power reference value that is the output power of the motor and the output power per unit time after the initial operation of the motor A2 is within the allowable range, and the ratio is not within the allowable range. If this happens, the abnormality of the motor A2 is detected. As a result, even when the motor A2 continues to rotate at a constant speed, it is possible to realize highly accurate motor abnormality detection.

  Further, when the motor A2 continues to rotate by repeating the same speed pattern, the output power of the speed pattern in the initial operation of the motor A2 and the output power for each speed pattern after the initial operation of the motor A2 are calculated, and the initial operation of the motor A2 is performed. It is determined whether or not the ratio between the output power reference value, which is the output power of the speed pattern, and the output power for each speed pattern after the initial operation of the motor A2 is within the allowable range, and the ratio is within the allowable range. If it is determined that there is no abnormality, the abnormality of the motor A2 is detected. Thereby, even when the motor A2 continues to rotate by repeating the same speed pattern, it is possible to detect the motor abnormality with high accuracy.

  Further, when the motor A2 continues to rotate by repeating the same speed pattern, the output power for each rotational speed in the speed pattern in the initial operation of the motor A2 and the output power for each rotational speed in the speed pattern after the initial operation of the motor A2. The ratio between the output power reference value, which is the output power for each rotational speed of the speed pattern in the initial operation of the motor A2, and the output power for each rotational speed of the speed pattern after the initial operation of the motor A2 is within an allowable range. If it is determined that the ratio is not within the allowable range, the abnormality of the motor A2 is detected. As a result, when the motor A2 continues to rotate by repeating the same speed pattern, the motor abnormality is detected according to the change in the output power for each rotation speed in the speed pattern, so that the motor abnormality can be detected with higher accuracy. be able to.

  In addition, when the rotation speed of the motor A2 is switched or the speed pattern is changed, the output power reference value is changed in consideration of the above-mentioned ratio in the number of operations at that time. Since the output power reference value is reset in consideration of the degree of deterioration of A2, more accurate motor abnormality detection can be realized.

  In the above-described embodiment, the abnormality of the motor A2 is detected by determining whether or not the ratio between the output power reference value and the output voltage is within the allowable range. However, the present invention is not limited to this. For example, the abnormality of the motor A2 may be detected by determining whether or not the difference between the output power reference value and the output voltage is within an allowable range. However, it is desirable to use the ratio because the abnormality of the motor A2 can be detected with higher accuracy.

  As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Inverter apparatus, 3a ... Speed adjustment part, 3b ... Electric power calculation part, 3c ... Abnormality detection part, 15 ... Inverter part, 16 ... Voltage detection circuit, 17 ... Current detection circuit, A2 ... Motor

Claims (5)

An inverter unit that converts a DC voltage into an AC voltage and outputs the AC voltage;
A voltage detection circuit for detecting an output voltage to the motor;
A current detection circuit for detecting an output current to the motor;
A power calculator that calculates output power from the output voltage detected by the voltage detection circuit and the output current detected by the current detection circuit;
An abnormality detection unit for detecting an abnormality of the motor from a change in the output power calculated by the power calculation unit;
A speed adjustment unit that controls the inverter unit to make the rotation speed of the motor constant,
When the motor continues to rotate at a constant speed, the power calculation unit calculates the output power per unit time in the initial operation of the motor and the output power per unit time after the initial operation of the motor,
The abnormality detection unit includes an output power reference value that is an output power of unit time in the initial operation of the motor calculated by the power calculation unit, and a unit time after the initial operation of the motor calculated by the power calculation unit. An inverter device comprising: determining whether or not a ratio with each output power is within an allowable range, and detecting an abnormality of the motor when determining that the ratio is not within the allowable range . An inverter unit that converts a DC voltage into an AC voltage and outputs the AC voltage;
A voltage detection circuit for detecting an output voltage to the motor;
A current detection circuit for detecting an output current to the motor;
A power calculator that calculates output power from the output voltage detected by the voltage detection circuit and the output current detected by the current detection circuit;
An abnormality detection unit for detecting an abnormality of the motor from a change in the output power calculated by the power calculation unit;
A speed adjustment unit that controls the inverter unit based on a speed pattern at which the rotation speed of the motor switches and adjusts the rotation speed of the motor;
The power calculation unit calculates the output power of the speed pattern in the initial operation of the motor and the output power for each speed pattern after the initial operation of the motor when the motor continues to rotate with the same speed pattern. And
The abnormality detection unit is an output power reference value that is an output power of the speed pattern in the initial operation of the motor calculated by the power calculation unit, and the motor after the initial operation of the motor calculated by the power calculation unit. An inverter device characterized by determining whether or not a ratio with output power for each speed pattern is within an allowable range, and detecting an abnormality of the motor when it is determined that the ratio is not within the allowable range . An inverter unit that converts a DC voltage into an AC voltage and outputs the AC voltage;
A voltage detection circuit for detecting an output voltage to the motor;
A current detection circuit for detecting an output current to the motor;
A power calculator that calculates output power from the output voltage detected by the voltage detection circuit and the output current detected by the current detection circuit;
An abnormality detection unit for detecting an abnormality of the motor from a change in the output power calculated by the power calculation unit;
A speed adjustment unit that controls the inverter unit based on a speed pattern at which the rotation speed of the motor switches and adjusts the rotation speed of the motor;
The power calculation unit, when the motor continues to rotate the same speed pattern repeatedly, output power for each rotational speed in the speed pattern in the initial operation of the motor and in the speed pattern after the initial operation of the motor Calculate the output power for each rotation speed of
The abnormality detection unit includes an output power reference value that is output power for each rotation speed of the speed pattern in the initial operation of the motor calculated by the power calculation unit, and an initial value of the motor calculated by the power calculation unit. It is determined whether or not the ratio of the output power for each rotation speed of the speed pattern after the operation is within an allowable range, and the abnormality of the motor is detected when it is determined that the ratio is not within the allowable range. An inverter device characterized by . 2. The inverter device according to claim 1, wherein when the rotation speed of the motor is switched, the abnormality detection unit changes the output power reference value in consideration of the ratio in the number of operations at that time . 4. The inverter device according to claim 2, wherein, when the speed pattern is changed, the abnormality detection unit changes the output power reference value in consideration of the ratio in the number of operations at that time .

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