JP2003111432A - Method for diagnosing fault of inverter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for automating the decision whether a plurality of semiconductor switching elements for forming an inverter main circuit of an inverter is respectively normal or not. SOLUTION: A drive signal for diagnosing a fault is, for example, outputted from a CPU circuit 11 to an IGBT2 according to a command from a touch panel or the like, a comparison calculation of a logic level output from a state detector 13 for detecting on or off state of the IGBT2 with a logic level of the drive signal is conducted by the CPU circuit 11, and its arithmetic result is displayed on a display unit of the touch panel. Equivalent circuits to a gate drive circuit 12 and the state detector 13 are respectively provided in the IGBT1, and the IGBTs3 to 6, and the same operations as that in the above circuit are conducted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of diagnosing a failure in an inverter device, which supplies AC power of a desired frequency and voltage to a load by turning on and off each of a plurality of semiconductor switching elements forming an inverter main circuit. Regarding

[0002]

2. Description of the Related Art A conventional inverter device of this type is provided with a diagnostic function for determining whether or not a plurality of semiconductor switching elements forming an inverter main circuit are normal, in the inverter device. Therefore, a serviceman generally checked whether or not the semiconductor switching element is normal.

[0003]

When a failure occurs in the conventional inverter device and it is necessary to determine whether each of the plurality of semiconductor switching elements forming the inverter main circuit is normal, the inverter is used. It is common to disassemble and check the relevant components of the device in advance, and this disassembling work requires skilled technology,
The problem is that it takes time to clarify the defective parts.

An object of the present invention is to provide a method of diagnosing a failure in an inverter device that solves the above-mentioned difficulties.

[0005]

According to a first aspect of the present invention, an inverter for supplying alternating current power having a desired frequency and voltage to a load by turning on and off each of a plurality of semiconductor switching elements which constitute an inverter main circuit. In a device failure diagnosis method, a drive signal for failure diagnosis is generated for each of the semiconductor switching elements, an ON / OFF state of the semiconductor switching element corresponding to the drive signal is detected, and the detected ON / OFF state is detected. Is compared with the drive signal for fault diagnosis.

A second aspect of the invention is to turn on and off each of a plurality of semiconductor switching elements constituting an inverter main circuit to supply AC power of a desired frequency and voltage to a load, and to the semiconductor switching element. A fault diagnosing method for an inverter device that also performs an operation of correcting the waveform of each of the drive signals based on the ON / OFF state of each of the semiconductor switching devices corresponding to each of the drive signals of Drive signal is generated, the ON / OFF state of the semiconductor switching element corresponding to the drive signal is detected, and the detected ON / OFF state is compared with the drive signal for fault diagnosis. And

According to the present invention, the inverter device has a built-in function of determining whether each of the plurality of semiconductor switching elements forming the inverter main circuit is normal. Therefore, by operating this function, a failure occurs. Disassembling work for specifying the semiconductor switching element is unnecessary.

[0008]

FIG. 1 is a circuit configuration diagram of an inverter device showing a first embodiment of the present invention.
In FIG. 1, in order to simplify the following description, some of the components related to the present invention are shown, and the other components are not shown.

That is, in FIG. 1, the inverter device is composed of, for example, an inverter main circuit 1 of a three-phase bridge connection in which each of IGBT1 to IGBT6 is a semiconductor switching element, a microprocessor, and the like. , A CPU circuit 11 that controls the protection and monitoring operations, a gate drive circuit 12 that turns on and off the IGBT 2 based on a drive signal from the CPU circuit 11, and a state detection circuit 13 that detects the on / off state of the IGBT 2. I have it.

The state detection circuit 13 is composed of a level shift circuit or the like for converting the collector potential of the IGBT 2 into the logic level of the CPU circuit 11, and, for example, the IGBT.
It is assumed that the state detection circuit 13 outputs a logic "H" level when 2 is in the on state, and the state detection circuit 13 outputs a logic "L" level when the IGBT 2 is in the off state. Similarly, from the CPU circuit 11 to the IGB
IGBT2 when the drive signal to T2 is logic "H" level
Is turned on, and the CPU circuit 11 causes the IGBT
It is assumed that the IGBT 2 is turned off when the drive signal to 2 is at the logic "L" level.

In FIG. 1, the gate drive circuit 12 and the state detection circuit 13 are provided only in the IGBT 2, and in the above, I
Only GBT2 is explained, but the remaining IGB
The T1 and the IGBT3 to the IGBT6 are also provided with circuits equivalent to the gate drive circuit 12 and the state detection circuit 13, respectively, and the same operation as that of the IGBT2 is performed.

Therefore, when some failure occurs in the inverter device shown in FIG. 1 and it is necessary to determine whether each of the IGBT1 to IGBT6 constituting the inverter main circuit 1 is normal, a touch panel or the like not shown is operated. Then, the CPU circuit 1 is operated by operating the failure diagnosis function.
1 outputs a drive signal for fault diagnosis to each of the IGBT1 to the IGBT6, and at this time, in the IGBT2, a comparison operation is performed between the logic level output from the state detection circuit 13 and the logic level of the drive signal corresponding to the drive signal. The CPU circuit 11 performs this, and displays the result of this failure diagnosis on the display of the touch panel. Here, since the repetition rate of the pulse of the drive signal is high during normal operation, it is difficult to compare the two logic levels. Therefore, the drive signal for fault diagnosis is, for example, the drive signal for normal operation. With a pulse width wider than the pulse width, for all IGBTs,
It is assumed that a drive signal for fault diagnosis is sequentially given to perform a comparison operation of both logic levels. That is, the inverter main circuit 1
If the CPU circuit 11 is made to sequentially perform the above-mentioned operation for all of the IGBTs constituting
It can be checked without removing the connection of each of BT1 to IGBT6.

FIG. 2 is a circuit configuration diagram of an inverter device showing a second embodiment of the present invention, and in FIG. 2, a part related to the present invention is shown in order to simplify the following description. The constituent elements are illustrated, and the other constituent elements are omitted.

That is, in FIG. 2, in addition to the inverter main circuit 1, the gate drive circuit 12, the state detection circuit 13 having the same function as the constituent elements shown in FIG.
A CPU circuit 21 composed of a microprocessor and the like, which controls the inverter device, protects it, and monitors it;
In order to improve the control performance of the inverter device, a drive signal from the CPU circuit 21 to the IGBT 2 and a state detection circuit 13
A pulse width correction circuit 22 for generating a new drive signal corrected so that the pulse width thereof is substantially equal to that of the detection signal from, and outputting the new drive signal to the gate drive circuit 12.

Further, when the drive signal from the CPU circuit 21 shown in FIG. 2 to the pulse width correction circuit 22 is at the logic "H" level, the IGBT 2 is turned on, and the CPU circuit 2 is turned on.
The drive signal from 1 to the pulse width correction circuit 22 is logic "L".
When the level is set, the IGBT 2 is turned off.

In FIG. 2, only the IGBT 2 has a pulse width correction circuit 22, a gate drive circuit 12, and a state detection circuit 13.
In the above description, only the IGBT2 is described. However, the remaining IGBT1, IGBT3 to IGBT6, pulse width correction circuit 22, gate drive circuit 12,
Each of the state detection circuits 13 is provided with an equivalent circuit, and the same operation as that of the IGBT 2 is performed.

Therefore, when some failure occurs in the inverter device shown in FIG. 2 and it is necessary to determine whether each of the IGBT1 to IGBT6 constituting the inverter main circuit 1 is normal, a touch panel or the like (not shown) is operated. The CPU circuit 2 is operated by operating the failure diagnosis function.
1 outputs a drive signal for fault diagnosis to each of the IGBT1 to IGBT6. At this time, in the IGBT2, a comparison operation is performed between the logic level output from the state detection circuit 13 and the logic level of the drive signal corresponding to the drive signal. The CPU circuit 21 performs this, and displays the result of this failure diagnosis on the display of the touch panel. Here, since the repetition rate of the pulse of the drive signal is high during normal operation, it is difficult to compare the two logic levels. Therefore, the drive signal for fault diagnosis is, for example, the drive signal for normal operation. The pulse width is wider than the pulse width, and a drive signal for fault diagnosis is sequentially applied to all the IGBTs to perform a comparison operation of both logic levels. That is, the above operation is sequentially performed by the CPU for all the IGBTs that configure the inverter main circuit 1.
If the circuit 21 does so, for example, the IGBT 1
~ It can be checked without removing the connection of each IGBT6, and in the case of this inverter device, additional installation of new hardware parts is not required.

In the description of the circuits of the above first and second embodiments, the case where a failure occurs in the inverter device has been described. However, a normal start-up is performed every time an operation command is given to this inverter device. Prior to the above, the diagnostic method of the present invention for outputting a drive signal for fault diagnosis is performed, and as a result,
If a failure of the inverter device is found, the failure can be displayed.

[0019]

According to the present invention, when a failure occurs in the inverter device and it is necessary to determine whether each of the plurality of semiconductor switching elements forming the inverter main circuit is normal, the semiconductor switching element is It becomes possible to generate a drive signal for failure diagnosis for each and automatically check the semiconductor switching element based on this drive signal.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of an inverter device showing a first embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of an inverter device showing a second embodiment of the present invention.

[Explanation of Codes] 1 ... Inverter main circuit, 11 ... CPU circuit, 12 ... Gate drive circuit, 13 ... State detection circuit, 21 ... CPU circuit,
22 ... Pulse width correction circuit.

Claims (2)

[Claims] 1. A fault diagnosing method for an inverter device, which supplies AC power of a desired frequency and voltage to a load by turning on and off each of a plurality of semiconductor switching elements forming an inverter main circuit, wherein the semiconductor switching element A drive signal for failure diagnosis is generated for each of them, an ON / OFF state of the semiconductor switching element corresponding to the drive signal is detected, and the detected ON / OFF state is compared with the drive signal for failure diagnosis. A method of diagnosing a failure in an inverter device, which comprises performing a calculation. 2. A plurality of semiconductor switching elements forming an inverter main circuit are turned on and off to supply alternating current power of a desired frequency and voltage to a load, and to drive signals to the semiconductor switching elements respectively. A method for diagnosing a failure in an inverter device, which also performs an operation of correcting the waveform of each of the drive signals based on the on / off state of each of the corresponding semiconductor switching elements, wherein a drive signal for failure diagnosis for each of the semiconductor switching elements is generated. However, an ON / OFF state of the semiconductor switching element corresponding to the drive signal is detected, and a comparison operation is performed between the detected ON / OFF state and the drive signal for fault diagnosis. Failure diagnosis method.