JP2001190060A - Inverter device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inverter device which surely removes surge and eliminates cost increase due to the removal. SOLUTION: The inverter device is provided with a rectifier circuit 4 which rectifies an alternating current, a smoothing circuit which generates a direct current by smoothing the rectified alternating current, and a switching circuit 7 which switches the direct current. The inverter device is also provided with a CRD snubber circuit 6 between the high-potential side 8 and low-potential side 9 of the direct current, and the resistor 13 of the circuit 6 is made to function as a discharge resistor. The snubber circuit 6 is constituted by serially connecting a diode 11 and a capacitor 12, both of which are oriented in the forward direction, in series in this order from the high-potential side between the high and low-potential sides 8 and 9 of the direct current and, in addition, connecting the resistor 13 in parallel with the capacitor 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter device.

[0002]

2. Description of the Related Art FIG. 2 is a circuit diagram showing a conventional inverter device. The inverter device 41 includes a rectifier circuit 44 formed by bridge-connecting diodes, and a smoothing capacitor 45.
, A discharge resistor 46, a switching circuit 47 using a switching transistor, and a surge absorbing capacitor 48 connected to the input side of the switching circuit 47. And the rectifier circuit 4
An AC power supply 42 is connected to an input side of the switching circuit 4, and a motor 43 for driving, for example, a compressor of an air conditioner is connected to an output side of the switching circuit 47.

In the inverter device 41, first, an AC supplied from an AC power supply 42 is rectified by a rectifier circuit 44,
This rectification is converted to DC by the smoothing capacitor 45. Then, this DC is switched by the switching circuit 47, and a PWM signal for driving the motor 43 so that the rotation speed is variable is formed. Surge generated during this switching operation is absorbed and removed by the surge absorbing capacitor 48.

[0004]

In the above-described conventional inverter device 41, the surge is absorbed by a single capacitor 48, but a CRD snubber circuit has been proposed as a circuit for more surely absorbing the surge. However, since the CRD snubber circuit is composed of a plurality of components of a capacitor, a resistor, and a diode, simply replacing the surge absorbing capacitor 48 with a CRD snubber circuit does not
There is a problem that the number of parts increases and this causes a cost increase.

[0005] In the inverter device 41,
The rectifying ripple is removed by the smoothing capacitor 45, and the surge is removed by the surge absorbing capacitor 48. These ripples and surges are both AC components superimposed on DC. The ripples have relatively low frequency components, whereas surges have sharp waveforms and contain high frequency components. Therefore, the inverter device requires both a circuit for removing ripples and a circuit for absorbing surges, and it is difficult to adopt a configuration that also serves as the other in order to avoid the above cost increase.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to eliminate a cause of an increase in cost while reliably removing a surge. To provide a simple inverter device.

[0007]

Therefore, an inverter device according to a first aspect of the present invention comprises a rectifier circuit 4 for rectifying an AC, a smoothing capacitor 5 for smoothing the rectification and converting the DC to a direct current, and a switching circuit 7 for switching the DC. The CRD snubber circuit 6 is provided between the high-potential side 8 and the low-potential side 9 of the DC, and the resistor 13 of the CRD snubber circuit 6 is a discharge resistor.

In this inverter device, the surge generated in the switching circuit 7 can be reliably absorbed and removed by the CRD snubber circuit 6, and the resistor 13 of the CRD snubber circuit 6 also functions as a discharge resistor, so that the number of parts increases. Can be suppressed.

Further, in the inverter device according to the present invention, the C
An RD snubber circuit 6 connects a forward-directed diode 11 and a capacitor 12 in series from the high-potential side between the high-potential side 8 and the low-potential side 9 of the direct current and in parallel with the capacitor 12. And a resistor 13 connected thereto.

In this inverter device, the configuration can be simplified.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, specific embodiments of the inverter device according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing the inverter device. The inverter device 1 is provided with a rectifier circuit 4 formed by bridge-connecting diodes on the input side to which the AC power supply 2 is connected. A smoothing capacitor 5 and a CRD snubber circuit 6 are provided in parallel between the output terminals of the rectifier circuit 4, and a switching circuit 7 using a switching transistor is provided on the output side of the inverter device 1. . The output terminal of the switching circuit 7 is connected to the motor 3 that drives, for example, a compressor of an air conditioner. The CRD snubber circuit 6 provided on the input side of the switching circuit 7 includes a diode 11 and a capacitor 12 which are disposed between the high potential side 8 and the low potential side 9 of the direct current in order from the high potential side 8 in the forward direction. Are connected in series, and a resistor 13 is connected in parallel with the capacitor 12.

In the inverter device 1, first, the AC supplied from the AC power supply 2 is rectified by the rectifier circuit 4. For this rectification, the diode 11 of the CRD snubber circuit 6
Becomes conductive. Therefore, the resistor 13 of the CRD snubber circuit 6 functions as a discharge resistor. Further, the ripple is removed from the rectification by the smoothing capacitor 5 to form a direct current. The DC thus formed is switched by the switching circuit 7 to form a PWM signal for driving the motor 3 at a variable rotation speed. The surge generated by this switching operation is absorbed and removed by the CRD snubber circuit 6.

In the above inverter device, since the CRD snubber circuit 6 is provided closer to the switching circuit 7 than the smoothing capacitor 5 and on the input side thereof, the surge generated in the switching circuit 7 can be reliably absorbed and removed. Can be. The resistor 13 of the CRD snubber circuit 6 is connected to the smoothing capacitor 5 and the capacitor 1 of the CRD snubber circuit 6.
Since it also functions as the second discharge resistor, there is no need to separately provide a discharge resistor. Therefore, the number of components can be reduced, and the provision of the CRD snubber circuit 6 can be prevented from increasing the cost.

Although the specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and can be implemented with various modifications within the scope of the present invention. In the above, the diode 11 and the capacitor 12
Are connected in series and the capacitor 12 and the resistor 13 are connected in parallel to form the CRD snubber circuit 6. By using such a CRD snubber circuit 6, the configuration of the inverter circuit 1 can be made simpler. However, if the discharge current of the smoothing capacitor 5 can be passed through the resistor 13, the CRD of another configuration can be used. A snubber circuit may be used.

[0016]

According to the inverter device of the first aspect, C
The resistance of the RD snubber circuit also functions as a discharge resistance. Therefore, it is possible to reliably eliminate the surge while avoiding the increase in cost.

Further, in the inverter device according to the second aspect, it is possible to reliably reduce the cost by simplifying the configuration.

[Brief description of the drawings]

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

FIG. 2 is a circuit diagram showing a conventional inverter device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inverter device 4 Rectifier circuit 6 CRD snubber circuit 7 Switching circuit 8 High potential side 9 Low potential side 11 Diode 12 Capacitor 13 Resistance

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H007 BB06 CA01 CC23 EA02 FA01 FA20 5H740 BA11 BB09 BB10 BC06 JA23 MM03

Claims (2)

[Claims] 1. An inverter device comprising: a rectifier circuit for rectifying an alternating current; a smoothing capacitor for smoothing the rectification and a direct current; and a switching circuit for switching the direct current. A CRD snubber circuit (6) is provided between the DC high potential side (8) and the low potential side (9), and the resistance (1) of the CRD snubber circuit (6) is set.
An inverter device wherein 3) is a discharge resistor. 2. The CRD snubber circuit (6) comprises a forward-directed diode (11) and a capacitor (12) between the DC high potential side (8) and the low potential side (9). 2. The inverter device according to claim 1, wherein the capacitors are connected in series from a high potential side, and a resistor (13) is connected in parallel with the capacitor (12).