JPH03243136A - Inverter - Google Patents

Abstract

PURPOSE:To reduce the size and to suppress noise leakage by arranging an inverter, a noise prevention shunt capacitor, a series reactor and a surge current preventing snubber circuit, closely to one another, in one metallic housing. CONSTITUTION:An A/D converting section 103 and a D/A converting section 104 are mounted on a circuit board 102 arranged in a metallic housing 101 thus constituting an inverter. Reactors 109R-109T are connected in series with input side lead wires 105R-105T and further connected through a shunt capacitor network 107 with an A/D converting section 103. Output lead wires 106U-106W from the D/A converting section 104 are connected with a shunt capacitor network 108 and series reactors 110U-110W. In the shunt capacitor networks 107, 108, capacitors are connected between I/O lines and the housing 101. Snubber circuits(not shown) are connected with commutators in the A/D converting section 103 and the D/A converting section. These components are arranged closely to one another.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an inverter device, and more specifically to an AC/DC converter and an inverter device that can effectively prevent leakage of electromagnetic noise within a limited space. In Figure 5, a capacitor is placed in parallel in close proximity to a diode placed in the inverter main body, and line filters are connected to the input side and the output side to suppress leakage of electromagnetic noise, respectively. FIG. 1 is a block diagram showing the configuration of a conventional inverter device. In the figure, 501 is an inverter device housing;
502 is a control circuit board housed therein. As is well known, this device receives three-phase power (consisting of R, S, and T phases) from the commercial frequency power supply shown on the left side of the figure, converts it to DC power, and then returns it to the desired frequency. three-phase power (U, V.

(consisting of W-phase) and supplies it to the load shown on the right side of the figure. 505R, 505S, and 505T are R, S, and T phase voltages from the power supply, respectively.

An input conductor that conducts current to the control circuit board 502 and 50
6U, 506V, and 506W are output side conductors that send out two voltage currents of the U, V, and W phases, which have been reconverted to the desired frequency, respectively, to the load. Reference numerals 511 and 512 indicate line filters (electromagnetic wave noise filters) connected to the input side and output side of the control circuit board, respectively, and both are arranged outside the inverter device housing 501.

As will be described later, the main parts of the control circuit board 502 are an AC/DC converter that converts commercial frequency power into DC power, and an inverter body that reconverts this into power at a desired other frequency, both of which are causes of electromagnetic noise. Become. The frequency component of the electromagnetic noise generated by the former is determined by the power supply frequency (commercial frequency) and the rectification method. On the other hand, the latter is determined by the switching frequency of the inverter itself, and is often much higher than the former, and has a wider spectrum width.

Line filters 511 and 512 are connected to the control circuit board 502
The electromagnetic noise generated inside the input/output side conductor 505R-T
, 506U~■. In the configuration shown in FIG. 5, the line filters 511 and 512 are configured independently and operate once.

In addition, there is a method in which two line filters are integrated to simplify the structure, published in Japanese Patent Laid-Open No. 63-19.
It is disclosed in Publication No. 4530.

FIG. 6 is a circuit diagram showing the configuration of one unit. In the same figure, 6o1 is AC power supply (commercial frequency), 602
603 is an inverter device, 603 is an inductive load (such as an induction motor), and 604 is a filter that prevents leakage of electromagnetic noise, all of which are illustrated as single line diagrams. 6
05 and 606 are conductive wires on the input side and output side, respectively.

In the inverter device 602, 607 is a rectifier circuit (AC/DC converter), 608 is an inverter main body, and 609 is a shunt capacitor for grounding noise voltage.

The filter 604 is disposed across the input and output terminals of the inverter device 602, and is composed of conductors 605 and 606 inserted in series, respectively, and a capacitor 612 that couples the axles 610 and 611 and the output side terminals of these axles. Ru.

Among the electromagnetic noise generated by the inverter device 602,
Particularly harmful are high-order harmonic components contained in the voltage and current of the inverter main body 608.

By the way, the circuit state regarding the above-mentioned high-order harmonic component is 9
Due to stray reactance between circuit components, etc., the result will not be as shown in FIG. 6. Regarding high-order harmonic components of electromagnetic wave noise, the equivalent circuit of the configuration shown in FIG. 6 is considered to be as shown in FIG. 7.

That is, one generation source is an equivalent high frequency power source 70 whose internal impedance is the high frequency starting force sh and the stray capacitance C53.
It is 1. Further, C, , C, is the inverter device 60
2 and the input/output side conductors 605, 606, respectively, resulting in 1 equivalent high frequency electric current m7o1. It is determined by the shape and size of each circuit blocker, including the filter 604, and the positional relationship between the two.

Resistance 702. The inductance 703 is a resistance component and a reactance component (
Inducibility). Similarly, resistance 704 and inductance 705 correspond to the resistance component and reactance component of inductive load 603, respectively. In the frequency domain of the electromotive force sh, the reactance values of the inductances 7()3 and 705 are extremely large compared to the resistance values of the resistors 702 and 704, respectively, and the reactance values of Cs+ and csZ are extremely large compared to those of the reactors 610 and 611, respectively. .

As is clear from FIG. 7, the impedance of a series circuit consisting of a reactor 611 and a capacitor 612 is connected in parallel to both terminals of the two-equivalent high-frequency power source 701. As mentioned above.

The reactance values of C3r and Csz are extremely large. Therefore, by appropriately selecting the values of the reactor 611 and the capacitor 612, and setting the impedance of the series circuit to a low value, the current flowing out from the 9-equivalent high-frequency power source 701 can be reduced to the above-mentioned value. It can be returned to the same power supply via a series circuit. In other words, with a relatively simple circuit configuration, it is possible to prevent high-order harmonic components of electromagnetic noise from flowing out via the stray capacitances c s + and c s z. Further, the low-order harmonic components of the magnetic noise are blocked by the actors 610 and 611.

[Problem to be solved by the invention]

However, the following problems have been pointed out regarding the inverter device shown in FIG. That is, since the line filters are arranged outside the casing of the inverter device on the input and output sides, the area occupied by the entire device increases, causing an increase in product cost. Furthermore, since the electromagnetic noise generator #j (circuit element in the inverter device) and the line filter are connected by a relatively long conductor, the impedance when looking outside the noise source is a relatively high value for high-order harmonic components. Therefore, not only is it difficult to effectively reduce these components, but also the conductor portion becomes a medium for diffusing inductive interference or radio wave interference into the surrounding space.

Furthermore, since the circuit structure of the configuration shown in FIG. 6 is too simple, it is considered difficult to suppress electromagnetic noise over a wide frequency band. Further, although a remarkable suppressing effect can be expected for the common mode component of electromagnetic noise, it is questionable whether the desired effect can be obtained for the normal mode component.

This invention was made in order to solve the above-mentioned problems, and it is possible to bypass the high-order harmonic components of electromagnetic noise with low impedance, and prevent the leakage of the remaining components and low-order high-frequency components. The purpose is to effectively prevent the inverter and The purpose is to provide a snubber filter function that suppresses electromagnetic waves generated from the converter at a closer position, and to achieve a satisfactory effect of suppressing leakage electromagnetic waves over a wide frequency band.

[Means to solve the problem]

In the inverter device according to the present invention, line filters on both input and output sides are housed in the inverter device housing, and both are arranged close to the AC/DC converter and the inverter main body, respectively. A group of shunt capacitors connecting each conductor on the input/output side of the line filter and between each conductor and the case, and a normal choke coil connected in series to each conductor are connected in cascade, and further connected to the AC/DC converter and the inverter main body. It is constructed by connecting a capacitor in parallel to each diode.

[Effect]

In the inverter device of the present invention, the electromagnetic noise generation source, the snubber filter, and the line filter are connected at the shortest distance, and the electromagnetic noise from the inverter main body and the diodes of the AC/DC converter is suppressed by the snubber filter, and the electromagnetic noise is suppressed along each conductor. Electromagnetic noise that attempts to propagate is effectively bypassed by each shunt capacitor between each conducting wire and between each conducting wire, and the remaining components are blocked by a normal choke coil. Furthermore, since the inverter device and the line filter are housed as one body in the same housing, the utilization rate of the dedicated space is greatly improved, and there is no interference caused by the conductor from the conductor to the surrounding space.

Radio interference is also reduced compared to conventional configurations.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 101 is a metal casing that mechanically protects the interior and electromagnetically shields the internal rain space;
Reference numeral 02 denotes a circuit board on which all the components of the internal device are mounted, and the two together constitute the inverter device according to the present invention. 105R.

105S and 105T use three-phase power (R,
Input side conductor that guides the S, T phase) to the device.

106U, 106V, and 106W are the output side conductors that send the three-phase power (U, V, and W phases) reconverted within the device to the external load, and their functions and roles are different from those shown in Figure 5. do not have. 103 is an AC/DC converter that converts three-phase power at a commercial frequency into DC power; 104 is an inverter body that receives DC power from the AC/DC converter 103 and reconverts it into three-phase power at a desired frequency; The frequency is determined by a switching frequency supplied externally (details not shown). 107 and 108 are shunt capacitor circuit networks, and as shown in FIGS.
, ct, (c, v, cv, , c-) and Cr connecting each conductive wire to the housing (zero potential point), respectively.

Cs0. Ct, (C, , Cv, , C, 1o). 109R, 109S, and 109T are normal mode choke coils connected in series to the input conductors 105R, 105S, and 105T, respectively, and 110U as well.
, ll0V, and ll0W are also normal mode choke coils, and are connected in series to the output side conductors 106U, 106V, and 106W, respectively. Between 103-107, 107-109R
It is necessary to shorten the intervals between -T, between 104 and 108, and between 108 and 1100 to ■ as much as possible, and at the same time, it is necessary to minimize the length of the conducting wire connecting these.

The input/output side conductors 105R-T and 106U-W are both three-wire two lines. As is well known, the transmission mode of the 3-wire line is
It can be decomposed into positive phase, negative phase and zero phase modes. In other words, a 3-wire line can be thought of as a superposition of positive-phase, negative-phase, and zero-phase lines that transmit each of the three transmission modes, and the transmission characteristics of these lines are equivalently equivalent to the 2-wire line model. You can consider it by replacing it with . Furthermore, noise induced in the positive-phase and negative-phase lines corresponds to normal mode noise in a two-wire line, and noise induced in the zero-phase line corresponds to common mode noise.

Also, two AC/DC converters 103 and an inverter main body 104
The circuit diagram of the snubber filter connected to the diode is as shown in FIGS. 3 and 4.

FIG. 3 shows the configuration of the circuit network of the AC/DC converter 103. In FIG.
e and 301f are rectifier diodes provided in the AC/DC converter 103, respectively, and 302a, 302b, 302c
, 302d, 302e, and 302f are snubber filters each having a capacitor connected in parallel with and close to the rectifying diodes 301a to 301f.

FIG. 4 shows the configuration of the circuit network of the inverter main body 104, 401a, 401b, and 401c in FIG.

401d, 401e 401f are switching elements (power transistors) of the inverter main body 104, and 402a, 402b, 402c, 402d, 402e
, 402f are the switching elements 401a to 401
It is a diode placed between the emitter and collector of f.

403a, 403b, 403c, 403d.

403e and 403f are the diodes 402a to 402
This is a snubber filter using a capacitor installed in parallel with f and at a close distance.

As described above, snubber filters 302a to 302f, 40
Diodes 301a to 303a to 303f are connected to the inverter main body 104 and the AC/DC converter 103.
1f and each of the diodes 402a to 402f,
By adopting a configuration in which the diodes 301a to 301f and the diodes 402a to 402f are arranged in parallel and close to each other, the diode recovery noise can be suppressed near the respective sources, and as a result, over a wide frequency band, A satisfactory effect of suppressing leakage electromagnetic waves can be achieved, and thereby the line filter can be further downsized.

In addition, as described above, the single-shunt capacitor networks 107 and 108 are located close to the AC/DC converter 103 and the inverter main body 104, respectively, and the conductors connecting them are also extremely short, so the high-order harmonic components of electromagnetic noise have a low impedance. is effectively bypassed. The remaining high-order harmonic components are effectively blocked by the nearby normal mode choke coils 109R to 109T and 110U to 110W. Since the wiring distance between each circuit element is significantly shortened in this way, the circuit state can be maintained with sufficient accuracy even for high-order harmonic components, and a filtering effect as theoretically predicted can be expected. Therefore, unlike the configuration shown in FIG. 6, the frequency band in which electromagnetic noise can be suppressed is not limited to a relatively narrow range, and furthermore, a satisfactory suppressing effect can be obtained on the normal mode component of noise. Furthermore, since the entire device is electromagnetically shielded by the metal casing, and in particular there is no exposed conductor portion as seen in the configurations of FIGS. 5 and 6, there is no radiation or induction of electromagnetic noise from this portion. Furthermore, since one circuit board and the line filter are integrally constructed and housed in the same housing, the dedicated volume is significantly reduced compared to the configurations shown in FIGS. 5 and 6. With the development of miniaturization technology for inductance elements and capacitance elements that is expected in the future, the above-mentioned improvement effects will become even more remarkable, contributing to miniaturization and economicalization of devices.

Note that although the power on the input and output sides are both depicted as three-phase power in Figure 1, the number of phases is not limited to three.
The present invention is applicable to single phase or other phase numbers (for example, four phases, six phases, etc.).

Further, the present invention is similarly applicable to cases where the number of phases on the input side and the output side are different (for example, three phases on the input side and four phases on the output side).

Further, in the above embodiments, the capacitor circuit network is explained using a Δ connection, but it may be configured as a Y connection. Even if a capacitor network is configured in a Y-connection, the effect is the same as in the case of a Δ-connection, and in addition, there is an advantage that the withstand voltage is halved and only one common mode capacitor is required.

〔Effect of the invention〕

As described above, according to the present invention, the AC/DC conversion means, the inverter main body, the input/output side filter means, and the snubber filter are housed in the same metal housing.

The line filter is composed of a group of shunt capacitors connecting each conductor on the input/output side and between each conductor and the casing, and a cascade connection with a choke coil connected in series to each conductor. The filter means on the output side and the output side are arranged close to the AC/DC converter means and the inverter body, respectively.

High-order harmonic components of electromagnetic noise can be bypassed with a low impedance, and leakage of remaining components and low-order high-frequency components can be effectively prevented with a choke coil. Furthermore, since the entire device can be made smaller and occupy less space, the device can be made more economical and the convenience of use can be improved.

Furthermore, a snubber filter is connected in parallel to each of the diodes of the inverter main body and the AC/DC conversion means.

In addition, by adopting a configuration in which the diode is placed close to the diode, diode recovery noise can be suppressed near the source, and a satisfactory leakage electromagnetic wave suppression effect can be achieved over a wide frequency band. Moreover, this allows further miniaturization of the filter means.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the configuration of an inverter device according to the present invention, FIG. 2 is an explanatory diagram showing the configuration of a shunt capacitor circuit network, FIG. 3 is an explanatory diagram showing the configuration of an AC/DC converter circuit network, and FIG. The figure is an explanatory diagram showing the configuration of the circuit network of the inverter main body, Figure 5 is an explanatory diagram showing the configuration of a conventional inverter device connected to line filters on the input and output sides, and Figure 6 is the configuration of a conventional inverter device. FIG. 7 is an explanatory diagram showing an equivalent circuit of the configuration of FIG. 6 regarding higher harmonics. In fig. 101-metallic casing 102-circuit board 103-/AC/DC comparator 104-inverter body 105R, 1053, 105T-input end conductor 106U,
106V, 106W - Output side conductor 107.108 - Shunt capacitor network 109R, 109S, 109T Input side normal mode choke coil 110U, ll0V, ll0W Output side normal mode choke coil 301a ~ 301f - Rectifier diode 302a ~ 302f, 403a ~ 403f snubber filter 401a to 401f-switching element 402
a to 402 f-Diode In the two figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] An inverter device comprising AC/DC converting means and orthogonal converting means housed in the same metal casing, and filter means for preventing leakage of electromagnetic noise from both of the means, comprising: the filter means. are a group of shunt capacitors connected between each conducting wire on the input side and the output side and between each conducting wire and the housing, a choke coil connected in series with each of the conducting wires, and the AC/DC converting means and the orthogonal converting means. An inverter device comprising a snubber filter disposed in parallel with and close to a connected diode.