JP3245985B2 - Inverter device with service life diagnosis function - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter device and, more particularly, to an inverter device having a life diagnosis function for predicting and determining the life and abnormality of a controlled device in advance.

[0002]

2. Description of the Related Art An example of the prior art of an invar device having a life diagnosis function for predicting and determining the life and abnormality of an inverter device and its controlled device in advance is disclosed in Japanese Patent Laid-Open No. 3-2.
69268 and JP-A-3-269269.

In these prior arts, only the life of a capacitor used in a DC intermediate circuit, a control power supply smoothing circuit, and the like in the inverter device is checked. That is, no consideration is given to other components in the inverter or the controlled device of the inverter. In the prior art, apart from the capacitor in the inverter, the life of other parts is not diagnosed, so when other parts actually fail, despite the fact that the life of the capacitor is diagnosed, The life of the whole system of the inverter device cannot be diagnosed. In such a case, a post-processing measure has been taken to investigate and find the faulty component and deal with it. For this reason, secondary disasters occur due to abnormalities, and the system is shut down urgently.
Preparation of repair parts, recovery work, etc. take a long time,
The operating rate of the entire system was reduced.

[0004]

SUMMARY OF THE INVENTION The present invention predicts the life of an apparatus (including an abnormality), predicts the life before an abnormality occurs, and implements preventive and predictive maintenance to ensure the safety of the entire system. And increase the operating rate. It is another object of the present invention to suppress a factor that affects the life of the system and to prevent the occurrence of an abnormality before the system is down due to the life.

[0005]

In order to achieve this object, an evaluation function for calculating a value for evaluating the life of the object to be diagnosed and setting means for setting conditions relating to the life, an operating state of the object to be diagnosed, Means for inputting data corresponding to the operating environment, operating means for calculating a value for evaluating the life of the object to be diagnosed using the evaluation function based on the input data, and operation of the operating means an inverter device including the conditions relating to the result and the life of the means for outputting a life warning signal or a warning signal, the first invention, the Starring
The life of the subject to be diagnosed based on the calculation result of the calculation means.
The factors related to life in the evaluation function are changed as
The second invention is characterized by the above-mentioned effects.
Based on the calculation result of the calculation means.
It is provided with a rotating abnormality avoiding control means.

[0006]

The inverter device calculates a value for evaluating the life of the object to be diagnosed using an evaluation function based on the input data corresponding to the operating state and the use environment of the object to be diagnosed. While outputting the life warning signal or a warning signal based on the condition, the first invention, the by the calculation result
Factors related to life expectancy may be prolonged, such as prolonging the life of the diagnosis target.
Changes, extending the service life and preventing abnormal occurrences.
Can be avoided. In the second invention, the above operation
Based on the results, it is driven to avoid abnormalities
Can increase the safety and operation rate of the entire system.
You.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows an embodiment of an inverter system which is connected to an AC power supply, converts the frequency thereof and drives an AC motor connected to the output, and which has a function of diagnosing the life according to the present invention. is there. In FIG.
Reference numeral 2 denotes a voltage type inverter device. An AC voltage from the AC power supply 1 is rectified by the rectifier circuit 3 to obtain a DC voltage. This DC voltage is smoothed by the smoothing circuit 4 and the inverter control circuit 14
The signal is converted into a pseudo sine wave through the inverter circuit 5 which operates with the signal of. The sine wave can have any frequency and voltage, and the sine wave is supplied to the AC motor 7 to control the rotation speed. Voltage signal 11 detected from smoothing circuit 4
The current signal 10 of the current detector 6 and the temperature and humidity signal 9 of the AC motor 7 detected by the temperature and humidity detector 8 are input to the control circuit 12 via the interface circuit 13. These signals are sent to the inverter control circuit 1
4 and the current diagnosis circuit 15. The result of the diagnosis circuit is output to the abnormality avoidance control 17 through the notice circuit 16. The abnormality avoidance control 17 outputs a signal for alarm to the alarm device 18 to give an alarm, and outputs a signal for abnormality avoidance to the inverter control circuit. The reading and writing of these internal states can be performed by the setting unit 19.

The short-life parts of the AC motor 7 include a coil and a bearing, and the description will be made by taking the coil prediction as an example.

[0010] The life of the coil depends on voltage, current, temperature, humidity,
Assuming that the function is determined by the frequency (the number of rotations), a function F shown in Expression 1 is defined as a life evaluation function.

[0011]

(Equation 1)

In equation (1), Tc is the temperature of the coil, and this Tc is obtained from equation (2).

[0013]

(Equation 2)

The service life is the standard service life when the component is used under predetermined standard conditions, but the service life deviates from the standard service life when used out of the standard conditions. That is, when used under the standard conditions, the integration of the sampling time can be simply used for determining the life, but when used under the standard conditions, it is necessary to make a correction to the sampling time. The function F is a weight function used for sampling time correction for this purpose. The sampling time is converted to a sampling time in a standard state by multiplying by the function F.

K1 to K6 are constants. Ta is the ambient temperature. The DC voltage Vd, the current I, and the frequency f are signals basically present in the inverter device, and the temperature Ta and the humidity H are signals from the detector. The reference voltage Vs, the reference temperature Ts, and the reference humidity Hs are values determined from actual results.

Next, a description will be given with reference to the flowchart of FIG. First, in step 101, various data K1 to K6, Ta, Vd, I, f, H, Vs, T
Input s and Hs. In step 102, the numerical value obtained from the heat generation by the current I and the cooling effect by the frequency f is calculated as the temperature T
The temperature Tc of the coil is obtained by adding the value to a. A function F is calculated using the coil temperature Tc obtained in step 102 (step 103). By multiplying the obtained function F by the sampling time Δt, Δt is converted into the sampling time Δt ′ in the standard state (step 10).
4). Sum Σ of the converted sampling times Δt ′
Δt ′ is obtained (step 105). The sum ΣΔt ′ represents the actual operation time in the standard state. The value of the sum ΣΔt 'is compared with a predetermined life time (step 106), and when the life time is exceeded, an alarm is output (step 10).
7) Notify that maintenance is required.

Although the life of the coil has been described as an example of the life prediction of the AC motor 7, the use of the cumulative operating time L (xi (t)) as a life evaluation function has been generalized. 3.

[0018]

(Equation 3)

Here, L (xi (t)); cumulative operating time xi (t); input signal t; time F; weighting function where xi (t) represents various data Ta, Vd, I, f, H, etc. It is a generalized representation.

Assuming that the actual accumulated operation time is operated under the condition of a predetermined standard as expressed by the equation 3, the operation time is calculated using the weighted function F (xi (t)). Must be changed to Approximately, ΣΔt is ΣF
(Xi (t)) Δt (= ΣΔt ′). In this way, by converting and accumulating the minute operation time (sampling time Δt) by using the weight function F (xi (t)) obtained from the state within the time, it is possible to compare with the judgment value and make the life diagnosis. It can be carried out.

In determining the life, a function other than the accumulated time can be used as the evaluation function. Next, a case where the accumulated time is not directly used will be described as another embodiment. The function used in this case can be considered in many ways.
To 7 are listed as typical ones. In other words, one that observes the temporal change in the result of the operation of the cumulative time function (function 1, judgment constant a),

[0022]

(Equation 4)

An arbitrary function G (xi (t)) is defined, and the result of the operation is checked (function 2, decision constant b),

[0024]

(Equation 5)

A function G (xi (t)) for observing a temporal change (function 3, decision constant c);

[0026]

(Equation 6)

And a change amount of the function G (xi (t)) with respect to the specific input xk (function 4, judgment constant dk);

[0028]

(Equation 7)

And the like. However, F (xi
(t)) and G (xi (t)) are functions, xi (t) is an input signal, xk is a specific input signal, and t is time.

When the result of operation by these functions reaches a certain value, it is determined that the life has expired.

Next, a description will be given based on the flowchart of FIG. Various data xi (t) is input (step 201), and a defined function G (xi (t)) is calculated (step 20).
2). As an example of the function G (xi (t)), for example, the above-described function Tc for obtaining the coil temperature can be considered. It is determined whether this calculation is the first time (step 2).
03) If it is the first time, various inputs xi (t) are stored as initial values (step 204), and the result of operation G (xi (t)) is also stored (step 205). Next, each input data xi (t) (=
αi (t)) and the calculation result G (xj (t)) (= αj (t)) are diagnosed using the subroutine shown in FIG. 4 (steps 206 and 207).

In the subroutine, each data αi (t) and calculation result αj (t) are compared with a predetermined value ak (i = k) (step 301), and are compared with an initial value αk (0) (step 301). 30
2) Then, a temporal change d {αk (t)} / dt is investigated (step 303), and a secondary change of time (second derivative of αk (t)) is investigated (step 304). Integral Σαk (t) Δ
t (step 305), and these steps 301
In steps 305 to 305, the respective results are compared with the determination constants ak, bk, ck, dk, and ek. If it is determined that the abnormality occurs within a predetermined period, a warning is output (step 306). Further, these functions can be used not only for a warning notice, but also for anomaly avoidance control for avoiding anomalies. For example, when G (xi (t)) is the coil temperature Tc in the above-described embodiment, if the coil temperature Tc is high, the current I is reduced or the frequency f is increased to lower the coil temperature Tc. Can be. This is the function 4 of Equation 7.
Thus, the degree of influence of the function G (xi (t)) on each factor xk is known. By the way, the stored comparison values and various functions (conditions) can be freely read out, and can be changed to more accurate ones by using the actual results. Further, by storing the past progress and results (results in Steps 301 to 305, failure results, and the like), they can be output as needed for reference of maintenance, and can be interfaced with an external computer or controller. It has become.

In the above description of the embodiment, the prediction of the coil of the AC motor has been described as an example, but this is merely an example and the present invention is not limited to this. For example, other parts of AC motors (bearings, etc.), main circuit parts of inverter devices (capacitors, wiring insulation, regenerative braking resistors, fans, etc.), control circuit parts (capacitors, resistors, connectors, etc.), AC There are components of a load device driven by an electric motor. The life function and conditions relating to the life of the component can be similarly set and calculated to predict the life. In particular, the life of the components of the load device often has know-how specific to the system to which it is applied.There is an area in which the life function and life conditions specific to the component can be set, and the inverter system designer or the user can set it by himself. It has become.

The operating condition and operating environment data of the object to be diagnosed include voltage, current, frequency (rotational speed), phase, power factor, etc. related to the operating condition of the inverter, and temperature and humidity related to the operating environment. Necessary information such as vibration, wind speed, electric field, magnetic field, and sound (including acoustic emission), and can be input as a signal from a detector or another device. Alternatively, necessary information can be obtained by calculation.

According to the present embodiment, since the processing speed does not require high speed, the available space and available time in the apparatus can be used, and the present invention can be easily applied. In addition, the life of the inverter and the system in which it is incorporated can be diagnosed, preventive maintenance can be performed so that maintenance and preparation can be performed before an abnormality occurs. Generation can be prevented before it occurs. In addition, since each data, function, and operation state can be freely read and changed, accurate functions and conditions that have been achieved can be created. Further, the past progress can be stored, which is useful at the time of maintenance. In addition, the avoidance control circuit can increase the operation rate of the system by performing control to suppress the occurrence of an abnormality from the time of occurrence of a notice to the end of maintenance, or even during normal operation.

[0036]

According to the present invention, it is possible to diagnose the life of an inverter and a system incorporating the inverter, and to perform preventive maintenance in which maintenance and preparation can be performed before an abnormality occurs. Further, by suppressing the occurrence of the abnormality by the abnormality avoidance control, it is possible to improve the operation rate and prevent the occurrence of a failure.

[Brief description of the drawings]

FIG. 1 is a drive system configuration diagram showing an embodiment of the present invention.

FIG. 2 shows a flowchart of one embodiment of the present invention.

FIG. 3 shows a flowchart of another embodiment of the present invention.

FIG. 4 shows a flowchart of a subroutine program according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Power supply, 2 ... Inverter, 3 ... Rectifier circuit, 4 ... Smoothing circuit, 5 ... Inverter circuit, 6 ... Current detector, 7 ... AC motor, 8 ... Temperature and humidity detector, 9 ... Temperature and humidity signal, 10 ... current value signal, 11 ... DC voltage signal, 12 ... control circuit, 13 ... interface circuit, 14 ... inverter control circuit, 15 ... diagnostic circuit, 16 ... notice circuit, 17 ...
Abnormality avoidance control circuit, 18 alarm device

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-261877 (JP, A) JP-A-3-202787 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02M 7/48

Claims (2)

(57) [Claims] 1. A setting means for setting a condition related to the evaluation function and life for calculating the value for evaluating the diagnostic object lifetime, and means for inputting data corresponding to the diagnostic object operating condition or use environment Calculating means for calculating a value for evaluating the life of the object to be diagnosed using the evaluation function based on the input data; and a life prediction signal or a warning based on a calculation result of the calculation means and a condition regarding the life. An inverter device having a means for outputting a signal, comprising: a means for changing a factor related to a life in the evaluation function so as to extend a life of a diagnosis target based on a calculation result of the calculation means. An inverter device with a life diagnosis function. 2. A setting means for setting an evaluation function for calculating a value for evaluating the life of the object to be diagnosed and a condition relating to the life, and a means for inputting data corresponding to an operating state and a use environment of the object to be diagnosed. Calculating means for calculating a value for evaluating the life of the object to be diagnosed using the evaluation function based on the input data; and a life prediction signal or a warning based on a calculation result of the calculation means and a condition regarding the life. An inverter device comprising a means for outputting a signal, comprising: an abnormality avoiding control means operating to avoid occurrence of an abnormality based on a calculation result of the calculating means.