JPH07163045A - Inverter - Google Patents

Abstract

PURPOSE:To detect a wear-out time of a capacitor in an inverter, in which the capacitor is used for smoothing a DC voltage. CONSTITUTION:An inverter comprises a voltage detector 40 for detecting a terminal voltage of a capacitor 6, a CPU 41 for carrying out control processing, a counter 42 for counting a discharge time of the capacitor 6, a non-volatile memory 43 for storing the counted value from the counter 42, and an indicator 44 for indicating the necessity for replacement of the capacitor 6. The indicator 44 functions when a transition time (t1) from a given set voltage V1 to a given set voltage V2 becomes smaller than a previously set time (t0).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter device having a capacitor for smoothing a DC voltage.

[0002]

2. Description of the Related Art FIG. 3 shows a circuit configuration diagram of a conventional voltage source inverter device. Power is supplied from a commercial power source 1 to a voltage source inverter device 3 via a contact 2 of an electromagnetic contactor, and the voltage source inverter device 3 is supplied. Convert to the desired AC power source by
For example, power is supplied to a load 4 such as an electric motor,
The voltage source inverter device 3 includes a rectifier 5 that converts an AC voltage into a DC voltage, a capacitor 6 that smoothes an output of the rectifier 5,
The control circuit 8 includes an inverter 7 that converts a DC voltage into an AC voltage, a CPU that controls the inverter device 3, and a drive circuit.

The capacitor 6 of the conventional voltage source inverter device uses an electrolytic condenser because it requires a large electrostatic capacity, but this electrolytic capacitor is a component that wears and its life time is longer than that of other components. However, if the electrolytic capacitor is worn out, it is necessary to replace it with a new one.

[0004]

In the conventional voltage type inverter device, an energization time meter is installed outside or inside the voltage type inverter device in order to replace it with a new one when the above-mentioned electrolytic content is worn. Alternatively, the energization time is estimated from the state of use, and it is determined that the replacement time due to wear has arrived when the predetermined energization time has elapsed.

An object of the present invention is to add a function for detecting a decrease in capacitance due to wear of the electrolytic content in the voltage type inverter device in order to replace the electrolytic content with a new one due to wear. .

[0006]

In order to solve the above problems, according to the present invention, in an inverter device having a capacitor for smoothing a DC voltage, when the input power of the main circuit of the voltage source inverter device is cut off, Detecting means for detecting the terminal voltage of the capacitor, measuring means for measuring the discharge time of the capacitor by the output value of the detecting means, storage means for storing the measured value of the measuring means, and storage value of the storing means And a display means for displaying that the value has become smaller than a predetermined value, and the measuring means displays the output value of the detecting means between a plurality of different predetermined voltage setting values. It measures the passing time.

[0007]

According to the present invention, when the input power of the main circuit of the inverter device having the capacitor in the DC circuit is cut off, the discharge time when the electric charge of the capacitor is discharged is measured, and the capacitor is worn and the capacitor is discharged. When the capacitance decreases, the discharge time becomes shorter than that of a new product (before wear), and the life of the capacitor is judged.

[0008]

FIG. 1 is a circuit configuration diagram of a voltage type inverter device showing an embodiment of the present invention. Components having the same functions as those in FIG. I will mainly explain things. That is, in FIG.
Is a voltage detector for detecting the terminal voltage of the capacitor 6, 41
Is a CPU for control calculation, 42 is a counter for measuring the discharge time of the capacitor 6, 43 is a non-volatile memory for storing the count value of the counter 42, 44 is an indicator for notifying replacement of the capacitor 6, and 45 is a conventional inverter device. It is a drive circuit of the inverter 7 having the same function as the control circuit of.

The operation of the present invention will be described with reference to the waveform chart shown in FIG. In FIG. 2, the contact 2 of the electromagnetic contactor
When is turned off, the terminal voltage Edc of the capacitor 6 is discharged at the time of starting operation after a lapse of time indicated by Edc ₀ (thin line), and passes a predetermined voltage set value V ₁ and V ₂ (V ₁ > V ₂ ). The time t ₀ to be measured is measured by the counter 42 via the voltage detector 40 and the CPU 41, and is stored in the nonvolatile memory 43 as t ₀ .

After the start of service, each time the contact 2 of the electromagnetic contactor is switched from ON to OFF, the time for passing through V ₁ and V ₂ is measured by the same method as described above, and the measured value is set to t ₁ and the nonvolatile value is set. Stored in the characteristic memory 43, and t ₁ when discharged after a lapse of time indicated by Edc ₁ (thick line) is a value T ₀ (T ₀ = K ₀ ) obtained by multiplying t ₀ by a predetermined coefficient K (K <1). When it becomes smaller than t ₀ ), the display unit 44 displays that the condenser 6 is about to be replaced.

It should be noted that, when the predetermined time T ₁ is replaced with the time t ₁ instead of the time T ₀ , and T ₁ > t ₁ , the indicator 44 indicates that the capacitor 6 is about to be replaced. Can also be displayed. Further, a plurality of predetermined voltage setting values are provided in the circuit configuration of FIG. 1, and the display 44 displays the result obtained by comparing the time for passing each voltage setting value with the predetermined time value corresponding to the number of voltage setting values. It is also possible to display it.

[0012]

According to the present invention, in the inverter device having the capacitor for smoothing the DC voltage, the wear time of the capacitor is reflected in the use environment and the use condition.
As compared with the conventional method, it is possible to detect more accurately, and it is possible to accurately know when the capacitor is new and when to replace it.

[Brief description of drawings]

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

FIG. 2 is a waveform diagram illustrating the operation of FIG.

FIG. 3 is a circuit configuration diagram showing a conventional example.

[Explanation of Codes] 1 commercial power supply 2 electromagnetic contactor 3 voltage source inverter device 4 load 5 rectifier 6 capacitor 7 inverter 8 control circuit 40 voltage detector 41 CPU 42 counter 43 non-volatile memory 44 indicator 45 drive circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H02M 7/48 M 9181-5H

Claims (2)

[Claims] In an inverter device having a capacitor for smoothing a DC voltage, a detecting means for detecting the terminal voltage of the capacitor when the input power of the main circuit of the inverter device is cut off, and an output value of the detecting means. A measuring means for measuring the discharge time of the capacitor, a storage means for storing the measured value of the measuring means, and a display means for displaying that the stored value of the storing means has become smaller than a predetermined value. An inverter device characterized in that 2. The inverter device according to claim 1, wherein the measuring means measures the time taken for the output value of the detecting means to pass between a plurality of different predetermined voltage set values. Inverter device.