JP3250603B2 - Inverter device with built-in DC reactor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an inverter device.

[0002]

2. Description of the Related Art A conventional inverter device is configured as shown in FIG. In the figure, 31 is a diode rectifier circuit, 32 is a smoothing capacitor, 33 is an inverter,
Reference numeral 34 denotes an inrush current suppression resistor, and reference numeral 35 denotes a short circuit contactor for inrush current suppression resistor. Reference numeral 30 denotes an inverter device having the above-described components therein, and includes P1, P2, R to T, and U to W.
And the like are external terminals provided on the inverter device. Reference numeral 36 denotes a DC reactor.
Was external.

[0003]

However, in the prior art, since a DC reactor is optional, a smoothing capacitor inside the inverter device is selected to have a large capacity under the condition that the DC reactor is not provided. . For this reason, there has been a problem that reduction in size and cost has been hindered. This smoothing capacitor is large in both size and weight, and has been a bottleneck in reducing the size and weight of the inverter device. Accordingly, an object of the present invention is to provide an inverter device capable of reducing the capacity of a smoothing capacitor and realizing a small size and low cost.
Is to provide .

[0004]

An inverter device according to the present invention is provided.
Field has a built-in DC reactor, which is used in the DC input
If, to bypass the DC reactor, DC REACT
Makes the two cores partially oppose each other via a magnetic gap
And a core structure in which a closed magnetic circuit is formed, and
Two permanent magnets arranged with the same polarity facing each other,
In the direction opposite to the direction of the bias magnetic flux created by the permanent magnet
A coil wound around the core structure to generate a magnetic flux;
It is composed of

[0005]

[0006]

Embodiments of the present invention will be described. FIG. 1 is a circuit block diagram showing a configuration of a DC reactor built-in type inverter device according to the present invention. In the figure, 1 is a diode rectifier circuit, 2 is a DC reactor built in the inverter device 3, 3 is a smoothing capacitor, and 4 is an inverter unit. Reference numeral 5 denotes a smoothing capacitor 3 from the diode rectifier circuit 1 when the power is turned on.
The reference numeral 6 denotes an inrush current suppressing resistor short-circuiting contactor for suppressing an inrush current flowing into the contactor. Reference numeral 10 denotes an inverter device having the above-described components therein, and P1 to P3, R to
T, U to W, etc. are external terminals provided in the inverter device. Reference numeral 7 denotes a short-circuit bar. When the AC power supply is used, short-circuit the terminals P1 and P2 with the short-circuit bar 7, and in the case of a DC input power supply, remove the short-circuit bar 7 and connect a DC power supply between the terminals P1 and N. Connect and use.

[0007] The DC reactor used will be briefly described. The direct current reactor according to Japanese Patent Application No. 7-322270 of the present applicant is suitable because the permanent magnet for bias does not demagnetize and the magnetic flux is hardly saturated in the core and can be miniaturized. FIG. 2 is a front sectional view showing the configuration of the DC reactor. As shown, an E-shaped core 21 made of a soft magnetic material
The EI-shaped core structure 20 is formed by combining the shaped core 22 with the mating surface 26 while providing a magnetic gap 25 in the center leg 21c. The two rectangular permanent magnets 24 are made parallel to the I-shaped core 22, and the same poles are placed between the magnetic poles 2 with the central leg 21 c interposed therebetween.
5 so as to face each other. Also, the center leg 21
For c, as the magnetic flux phi _e by the coil 23 moves toward the magnetic gap 25 from the center leg 21c, the coil 23 is wound, the bias magnetic flux phi _m making the magnetic flux phi _e and the permanent magnet 24 to produce the coil 23 from each other opposite. With this configuration, the magnetic flux φ _e of the coil 23 does not pass through the permanent magnet 24,
Eddy current loss is reduced, and the permanent magnet is not demagnetized, so that an inexpensive permanent magnet can be used. Magnetic flux φ of coil 23
_{Since e} and the bias magnetic flux φ _m of the permanent magnet 24 cancel each other in the opposite directions, the magnetic flux inside the core is reduced, it is difficult to saturate, and the reactor can be downsized by reducing the cross-sectional area of the core.

Next, the operation of the above-described inverter device will be described. Although there is no particular difference in operation from the conventional one, by incorporating a DC reactor, the power factor is normally improved. Therefore, the output current of the diode rectifier circuit decreases, and the ripple current of the smoothing capacitor decreases. Since the capacity of the capacitor is selected based on the allowable ripple current, the capacity of the capacitor can be reduced according to the DC reactor incorporated therein. The ripple current of the smoothing capacitor in the inverter device is represented by Expression (1). I _C [rms] = [I _CON ² [rms] + I _DC ² [rms] −2 I _DC [av]] ^1/2 (1) where I _C [rms]; ripple current of the smoothing capacitor I _CON [rms] The diode rectifier circuit output current I _DC [rms]; the inverter bus current I _DC [av]; the same average value The diode rectifier circuit output current I _CON [rms] in equation (1) is
Equation (2) is obtained.

I _CON [rms] = I _DC [av] / φ where φ: power supply power factor As an example, the power supply power factor is improved from 65% (no DC reactor) to 90% (3-4% reactor). Thus, the capacitor ripple current is reduced to about 60%. Also, when the DC reactor built-in type inverter device is used as a DC input, the DC bus current oscillates with the DC reactor and the smoothing capacitor, so that the DC reactor can be easily bypassed.

[0010]

According to the present invention, the power supply power factor can be improved by providing a DC reactor as standard equipment in the inverter device, the capacity of the smoothing capacitor can be reduced, and the size and cost can be reduced. In addition, since the DC reactor can be easily bypassed, the DC reactor built-in type inverter device can be easily adapted to DC input.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a DC reactor built-in inverter device according to the present invention.

FIG. 2 is a front sectional view showing a configuration of a DC reactor.

FIG. 3 is a block diagram showing a configuration of a conventional inverter device.

[Explanation of symbols]

 1, 31 Diode rectification circuit 2, 36 DC reactor 3, 32 Smoothing capacitor 4, 33 Inverter unit 5, 34 Inrush current suppression resistor 6, 35 Contactor for inrush current suppression resistor short circuit 7 Shorting bar 10, 30 Inverter device 20 Core structure 21 E-shaped core 21c Central leg 22 I-shaped core 23 Coil 24 Permanent magnet 25 Magnetic gap 26 Mating surface

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-285970 (JP, A) JP-A-7-194144 (JP, A) JP-A-5-93025 (JP, U) (58) Field (Int.Cl. ⁷ , DB name) H02M 7/48 H02M 7/04

Claims (1)

(57) [Claims] 1. A parallel circuit of a diode rectifier circuit having a three-phase input terminal, a rush current suppressing resistor and a contactor for suppressing a shunt current short-circuit, wherein a rectified output of the diode rectifying circuit is supplied via a DC reactor . An inverter device including a smoothing capacitor connected to a circuit and an inverter unit connected to the smoothing capacitor, wherein the DC reactor is built-in, and when used with a DC input, the DC reactor is bypassed.
The DC reactor can pass the two cores in a magnetic gap
Core structure in which a closed magnetic circuit is formed to face through
And 2 arranged with the same polarity facing the core structure.
Permanent magnets and the direction of the bias magnetic flux created by the permanent magnets
Wound around the core structure so as to generate magnetic flux in the direction opposite to
An inverter device with a built-in DC reactor, characterized by being constituted by a turned coil .