JPH0775452B2 - Abnormality detection device for inverter device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an abnormality detection device for an inverter device, and in particular, an abnormality current detection control unit is improved so that the cause of abnormality can be determined. Regarding

(Prior Art) FIG. 7 shows a configuration of a general inverter device. Explaining this, the power from the AC power supply 1 is converted into DC by the converter 2 and supplied to the inverter 4, while the operation signal from the operation unit 6 is input to the control unit 7 and driven from the control unit 7. The rotation speed is instructed to the inverter unit 4 via the signal generation unit 8. The inverter unit 4 performs pulse width modulation on the direct current supplied from the converter unit 2 based on the instruction of the number of revolutions to convert it into an alternating current, and also drives a motor 5 such as a refrigerant compressor motor of an air conditioner.

Further, the abnormality detection device incorporated in such an inverter device will be described. The input current of the motor 5 is detected by the current detection circuit 3 as the DC input current of the inverter unit 4 and sent to the control unit 7. When the control unit 7 determines that the current signal is abnormal, the control unit 7 causes the display circuit 9 that displays the abnormality to display the current abnormality.

This will be described in more detail with reference to FIG. 8. The current signal detected by the current detection circuit 3 and the abnormality determination charge signal from the determination generation circuit 10 are compared by the comparator 11, and the detected current value is abnormal. When the judgment current value is exceeded, an abnormality signal is supplied to the display circuit 9 to display the abnormality, and an operation signal from the operation unit 6 is supplied to the inverter forced stop circuit 12 which is passed to the drive signal generation unit 8. , The via line is cut off.

As described above, conventionally, the abnormality detection in the inverter has been performed only by the current value detected by the current detection circuit 3.

Therefore, although the abnormality of the inverter device including the motor 5 can be detected, the cause of the abnormality cannot be determined because the abnormality factor, restraint (motor lock) or overload (motor breakdown) cannot be detected separately. The serviceman was doing it.

By the way, if the cause of the abnormality is motor lock, it is usually necessary to replace the motor because the motor itself has failed, but in the case of motor breakdown, factors other than the motor, power supply abnormality or installation in the air conditioner It often stops working due to lack of circulating refrigerant amount in the place, refrigeration cycle, failure of ventilation system, etc. The motor is very likely to move by eliminating these causes, and the motor is often not replaced. Therefore, when repairing, it is important to distinguish whether the cause of the abnormality is a motor lock or a motor breakdown, and the method of coping with this is greatly different, and it is particularly important for the service person to identify the cause of the abnormality.

However, determining the cause of this abnormality is difficult and time consuming, requires specialized knowledge, and can sometimes lead to erroneous decisions. This is because, for example, a motor lock is mistakenly determined to be a motor lock even if the cause is a motor breakdown, so if a cause other than the motor is removed, the motor that does not malfunction despite being in motion will be replaced with a new motor. Or, on the contrary, even though the motor is locked, it is judged to be a motor breakdown, and there has been a problem that an abnormal portion cannot be found forever.

(Problems to be Solved by the Invention) As described above, when the abnormality detection in the inverter is performed only by the current value detected by the current detection unit, the abnormality of the inverter device can be detected, but the cause of the abnormality must be detected. Even if he could not do so and had expert knowledge, it took a lot of time to judge the cause of abnormality.

In addition, as a protection of the motor of the compressor, etc.
2741, JP55-8274, JP58-130724
JP-A-59-172996, JP-A-60-223938 and JP-A-60-223938 disclose that these conventional techniques stop the motor when the current value of the motor exceeds a predetermined value. The cause has not been detected yet.

Therefore, an object of the present invention is to provide an abnormality detecting device for an inverter device, which can eliminate the above-mentioned problems and can easily determine the cause of the abnormality by detecting the operating state quantity other than the current value.

[Configuration of the Invention] (Means for Solving the Problem) An abnormality detecting device for an inverter device according to the present invention outputs an abnormality signal when the current flowing through the inverter device exceeds an abnormal value, and the abnormality of the inverter device stops the motor. In the detection device, when the above abnormality signal is output, judge whether the cause of the abnormality is motor lock or motor breakdown based on the time from motor start to stop, the motor stop frequency value, or the amount of current change when the motor is stopped. It is equipped with means.

This determination means makes a determination using any one of them because the time from the start-up to the occurrence of an abnormality, the frequency, and the amount of change in the current flowing in the inverter device differ between motor lock and motor breakdown.

In this case, a predetermined time is set in the middle of the different time from startup due to motor lock and motor breakdown to the occurrence of an abnormality, and the judgment reference time signal is output after counting from startup and the set predetermined time has elapsed. The judgment means is composed of a judgment circuit for judging and displaying whether the cause of the abnormality is motor lock or breakdown depending on the presence or absence of this output.

Further, a forced stop circuit for stopping the motor may be provided separately from the abnormal signal when the judgment reference change signal is output from the current change detection circuit.

(Function) Since the time from startup to abnormal stop, the frequency value of the inverter device at the time of abnormal stop, and the amount of change in the current flowing through the motor differ between motor lock and motor breakdown, the determination means determines which of these By detecting whether or not the motor is stopped by the output of the abnormal signal, it is determined whether the cause of the abnormal motor stop is motor lock or motor breakdown.

Therefore, in the above configuration, when the determination means determines the time from the start of the motor to the stop, when the current flowing through the inverter device exceeds the abnormal value and the abnormal signal is output and the motor stops, the abnormality from the motor start The presence or absence of a determination reference time signal that is output when the time until the signal is input exceeds a preset predetermined time is determined to determine whether the cause of the abnormality is motor lock or motor breakdown.

Further, when the judging means judges the motor stop frequency value, the presence or absence of the judgment reference frequency signal output when the frequency value at the time of abnormal stop exceeds a predetermined value set in advance detects the cause of the motor lock. Or motor breakdown.

Further, when the judging means judges the current change amount when the motor is stopped, it is output when the current change amount when the motor is abnormally stopped exceeds a predetermined value. The presence or absence of a judgment reference change signal is detected to determine whether the cause of the abnormality is motor lock or motor breakdown.

(Embodiment) The following will describe an embodiment of the present invention with reference to FIGS. 1 to 7.

Since FIG. 7 is the same as the conventional one, its explanation is omitted.

FIG. 1 is a first diagram of an abnormality detection device for an inverter device according to the present invention.
An example is shown.

Detection current signal from current detection circuit 3 and judgment value generation circuit
The first comparator 11 compares the abnormality determination current signal of 10 with
The comparison output is supplied to the judgment circuit 19 having a display function and the inverter forced stop circuit 12. The inverter forced stop circuit 12 outputs the operation signal from the operation unit 6 to the drive signal generation unit 8
When the detected current value exceeds the abnormality judgment current value, it is turned on by an abnormal signal output, and the above line is cut off.

The ON operation signal and the judgment value generation circuit among the operation signals of the operation unit 6
The second comparator 15 compares the judgment ON signal of 14 with the second comparator 15, and supplies the timer output to the judgment circuit 19 in addition to the timer 16 which delays the comparison output for a predetermined time. Therefore, when the inverter device is driven, the judgment reference time signal is supplied to the judgment circuit 19 after a predetermined time has elapsed from the driving.

As will be described later, the judgment circuit 19 has a function of judging the cause of the abnormality in accordance with the output of the first comparator and the output of the timer, and displaying it.

The timer circuit as the detection circuit is composed of the second comparator 15 and the timer 16, and the judgment means is composed of this timer circuit and the judgment circuit 19.

FIG. 2 shows a second embodiment of the present invention. The difference from FIG. 1 is that the second comparator 15 is a comparator in which an inverter output as a frequency command operation signal and a judgment inverter output value are added. The output of the inverter is the judgment value generation circuit 24
The point is that the judgment reference frequency signal is output when the output value of the judgment inverter has been exceeded, and the memory 26 for storing the output of the judgment reference signal is provided. The contents stored in the memory 26 are read when an abnormal signal is output from the first comparator 11, and are reset by stopping the inverter device.

A memory circuit is composed of the comparator 25 and the memory 26.

Further, FIG. 3 shows a third embodiment of the present invention.
The difference from the figure is that the detection circuit compares the current change amount with the judgment current value of the judgment value generation circuit 34 by differentiating the detection current to detect the change amount of the current, and the current change amount is A second inverter configured to include a comparator 35 that outputs a judgment reference current change signal when the judgment current change value is exceeded, and disconnects the line between the operation unit 6 and the drive signal generation unit 8 by the judgment reference current change signal. This is the point that a forced stop circuit 22 is newly provided.

The differential circuit 36 and the comparator 35 form a current change amount detection circuit.

Now, in the configuration of the first embodiment as described above, when the operating unit 6 is operated to start the inverter device, the ON operation signal output from the operating unit 6 exceeds the determination value of the determination value generation circuit 14, An ON time signal is output from the comparator 15 and guided to the timer 16. The timer 16 outputs a judgment reference time signal after a lapse of a predetermined time after the ON time signal is input,
This is supplied to the judgment circuit 19.

On the other hand, when the current detected by the current detection circuit 3 exceeds the abnormality determination current Is set in the determination value generation circuit 10, an abnormality signal is output from the comparator 11, and this is supplied to the inverter forcing circuit 12 and the determination circuit 19. It

Therefore, since the inverter compulsory circuit 12 is turned on, the line connecting the operation unit 6 and the drive signal generation unit 8 is cut off and the motor 5 is stopped.

Further, the judgment circuit 19 detects the time shift of the abnormal signal with respect to the judgment reference time signal. That is, the abnormal signal is the judgment circuit
The presence or absence of the judgment reference time signal at the time of being input to 19 is judged, and the cause of the abnormality is displayed according to the judgment result.

Further, in the configuration of the second embodiment, similarly, the determination circuit 19 determines the presence or absence of the determination reference frequency signal at the time when the abnormal signal is input to the determination circuit 19, and the determination circuit 19 of the third embodiment In the configuration, the presence or absence of the judgment reference current change signal is judged.

Particularly in the third embodiment, when the judgment reference current change signal is output, it is supplied to the second inverter forced stop circuit 22, and the output also stops the motor 5.

By the way, when the current characteristic of the inverter device is normal, as shown in FIG. 4, after the starting current I _ON flows at the time of starting the motor,
The current value temporarily decreases as the motor rotation increases, and the current gradually increases as the inverter output increases, showing a constant current value change after the elapse of the steady operation output time.

Further, in the case of an abnormality, the current value changes shown in FIG. 5 when the motor is locked and shown in FIG. 6 when the motor is broken down.
In the case of FIG. 5, after the starting current I _ON flows at the time of starting the motor, the current value does not decrease because of the motor lock.
The current increases linearly as the inverter output increases, and exceeds the abnormality determination current value Is after ts time from startup. In the case of FIG. 6, after the starting current I _ON flows at the time of starting the motor, the current value temporarily decreases as the rotation of the motor increases, but since the rotation of the motor gradually decreases as the inverter output increases, The current value increases significantly. Therefore, the abnormality determination current value Is is exceeded after ts' time longer than that in the case of FIG.

From this, it is understood that the following three phenomena occur at the time of abnormality. First, the time from the start-up until the current detection value exceeds the abnormality determination current value Is is different between motor lock and motor breakdown, and is longer during motor breakdown (ts'> ts).

Secondly, the inverter output when the current detection value exceeds the abnormality determination current value Is, that is, the frequency command operation signal is different between the motor lock and the motor break down, and the motor output is larger during the motor breakdown.

Thirdly, the change in the current detection value at the motor lock is different from that at the motor breakdown, and it is larger at the time of the motor breakdown before and after the current detection value exceeds the abnormality determination current value.

Therefore, by examining the time, frequency, or current change value when the detected current value exceeds the abnormality determination current value, it is possible to know whether the cause of the abnormality is motor lock or motor breakdown.

However, in the first embodiment, since the presence or absence of the determination reference signal at the time when the abnormality signal is input to the determination circuit 19 is determined, the lock time ts until the current detection value exceeds the abnormality determination current value Is By setting the output timing of the judgment reference time signal in the middle between the judgment reference time signal and the breakdown time ts ′, the motor is locked if there is no judgment reference time signal, and the motor breaks if the judgment reference time signal already exists. It is possible to specify that it is down and display the specified abnormality content.

Further, in the second embodiment in which the frequency is detected and the third embodiment in which the change value of the current is detected, the presence or absence of the judgment reference frequency signal and the judgment reference current change signal is respectively judged, so these outputs By setting the timing of 1 to be in the middle of the motor lock and the motor breakdown, the abnormality content can be similarly distinguished.

Particularly, in the third embodiment, when the judgment reference current change signal is output, the line connecting the operation unit 6 and the drive signal generation unit 8 is cut off separately from the abnormal signal. At the time of motor breakdown in which the change in the current value becomes large earlier than when the motor is locked, the line can be cut off before the abnormal signal is output, and the protection of the inverter device can be increased. Since the judgment reference current change signal disappears after the abnormal signal is output, the first inverter forced stop circuit 12 that receives the abnormal signal and shuts off the line is indispensable.

As described above, according to the above-described three embodiments, a detection circuit that detects different operating state quantities according to the cause of an abnormality and outputs a determination reference signal when the operating state quantity exceeds a predetermined value;
By providing a judgment circuit that detects the presence or absence of the judgment reference signal of the detection circuit and judges the cause of the abnormality based on the presence or absence, it is possible to distinguish between motor lock and motor breakdown without requiring specialized knowledge. Easy to do,
As a result, repair can be performed quickly, and the problem of replacing a motor that has not failed is eliminated.

In each of the above embodiments, the presence / absence of the determination reference signal is directly determined at the time of outputting the abnormal signal, but the present invention is not limited to this.For example, the operating state quantity is first detected at the time of outputting the abnormal signal. After that, it is possible to compare the magnitudes of the operating state quantities to generate a determination reference signal and then determine the presence or absence thereof.

[Effects of the Invention] In summary, according to the present invention, when an abnormal signal is output, different operating state quantities, that is, the time until abnormal stop, the frequency value, and the amount of current change are detected. This makes it possible to determine the cause of an abnormality without requiring specialized knowledge, and has an excellent effect that repair can be performed quickly.

[Brief description of drawings]

1 is a block diagram of an abnormality detecting device for an inverter device according to a first embodiment of the present invention, FIG. 2 is a block diagram of the same second embodiment, and FIG. 3 is a block diagram of a third embodiment. FIG. 4 is a current characteristic diagram of the inverter device in a normal state, FIG. 5 is a characteristic diagram of the same when a motor lock is abnormal, FIG. 6 is a characteristic diagram of a same when a motor breakdown is abnormal, and FIG. FIG. 8 is a configuration diagram of an example of an inverter device common to the above, and FIG. 8 is a configuration diagram of an example of a conventional abnormality detection device. In the figure, 3 is a current detection circuit, 5 is a motor, 11 is a comparator that outputs an abnormal signal, 15 and 16 are timer circuits as detection circuits, 15 is a comparator, 16 is a timer, 15, 16 and 19 Is a determination circuit, 19 is a determination circuit, 12 and 22 are first and second inverter forced stop circuits, and 25 and 26 are memory circuits.
Is a comparator, 26 is a memory, 35 and 36 are current change amount detection circuits, 35 is a comparator, and 36 is a differentiating circuit.

Claims (5)

[Claims] 1. An abnormality detection device for an inverter device, which outputs an abnormality signal to stop the motor when the current flowing through the inverter device exceeds an abnormal value, wherein the motor is stopped for a period of time from when the abnormality signal is output to when the motor is stopped. An abnormality detection device for an inverter device, comprising: a determination unit that determines whether the cause of the abnormality is motor lock or motor breakdown based on either the frequency value or the amount of change in current when the motor is stopped. 2. A judging means for judging the time from the start of the motor to the stop is set to a predetermined time in the middle of the different time from the start to the abnormality due to the motor lock and the motor breakdown, and counting from the start. The timer circuit that outputs the judgment reference time signal after the set predetermined time has elapsed and the presence or absence of the judgment reference time signal from the timer circuit when the above abnormality signal is output, and the cause of the abnormality causes the motor lock to break down. The abnormality detection device for an inverter device according to claim 1, comprising a determination circuit for determining and displaying whether or not it is. 3. A judgment circuit for judging a motor stop frequency value, a memory circuit for outputting a judgment reference frequency signal when the frequency of the motor, which gradually rises from the start, exceeds a predetermined value, and storing this, and a memory circuit at the time of the abnormal output. The abnormality of the inverter device according to claim 1, further comprising: a determination circuit that detects the presence or absence of the determination reference frequency signal of the memory circuit and determines and displays whether the cause of the abnormality is motor lock or breakdown based on the presence or absence of the determination reference frequency signal. Detection device. 4. A change means for judging a current change amount when the motor is stopped detects a change amount of a current flowing through the inverter device and outputs a judgment reference change signal when the change amount exceeds a predetermined value. A circuit and a judgment circuit that detects the presence or absence of a judgment reference current change signal of the current change detection circuit when the above-mentioned abnormality signal is output, and judges and displays the cause of the abnormality as a motor lock or motor breakdown from the signal. An abnormality detection device for an inverter device according to claim 1, which is characterized in that. 5. The abnormality of the inverter device according to claim 4, further comprising a forced stop circuit for stopping the motor separately from the abnormality signal when the judgment reference change signal is output from the current change detection circuit. Detection device.