Electric power conversion systems – Current conversion – With cooling means
Reexamination Certificate
2000-10-18
2001-11-20
Patel, Rajnikant B. (Department: 2838)
Electric power conversion systems
Current conversion
With cooling means
C361S709000
Reexamination Certificate
active
06320776
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to power drive apparatuses, such as inverters and servo amplifiers, including switching devices for converting and outputting electric power. In particular, the present invention relates to a power drive apparatus, in which a filter is mountable, the filter serving to suppress the transmission of noise generated by the switching devices to an input power source.
2. Description of the Related Art
FIG. 7
is an exploded perspective view of a known separate-filter-type power drive apparatus.
In
FIG. 7
, the power drive apparatus includes a case
1
, a main circuit board
2
received in the case
1
and provided with an input terminal block
3
and a power module including switching devices for converting and outputting power, and a heat-dissipating plate
4
disposed at the bottom of the case
1
and for dissipating heat generated by heat-generating parts such as the switching devices mounted on the main circuit board
2
. A filter unit
6
, which is provided with a filter circuit including a choke coil, capacitors, and the like, is fixed by screws
5
to the heat-dissipating plate
4
at the bottom thereof. Relay wires
12
are connected with a filter-output-terminal block
8
at filter-side terminals
12
a
of the relay wires
12
and are connected with the input terminal block
3
at drive-side terminals
12
b
of the relay wires
12
, whereby the power drive apparatus and the filter unit
6
are connected to each other through the relay wires
12
. Power-source wires
10
are connected with a filter-input-terminal block
7
, whereby the filter unit
6
and a power source (not shown) are connected to each other through the power-source wires
10
.
The power drive apparatus including the filter unit
6
thus assembled is installed by screws
9
in an installation location.
As shown in
FIG. 8
, in the known separate-filter-type power drive apparatus, the filter unit
6
is disposed between a power source
11
and the input terminal block
3
, in which the filter unit
6
suppresses the transmission of noise to the power source
11
from the switching devices included in a power module
18
mounted on the main circuit board
2
.
However, in the known separate-filter-type power drive apparatus, the power source
11
and the filter-input-terminal block
7
were connected by the power-source wires
10
, and the filter-output-terminal block
8
and the input terminal block
3
were connected by the relay wires
12
, whereby productivity was decreased due to wiring processes, and the relay wires
12
must be prepared for interconnection due to the configuration of the separate-filter-type. The unit could not be reduced in size because the filter unit
6
was separated, and a mounting space for the filter unit
6
was required to be prepared outside the power drive apparatus. Moreover, when the power drive apparatus is used without using the filter unit
6
, the power-source wires
10
must be connected with the input terminal block
3
, and when the power drive apparatus is used together with the filter unit
6
, the power-source wires
10
must be reconnected with the filter-input-terminal block
7
and the relay wires
12
must be connected with the filter-output-terminal block
8
and the input terminal block
3
. That is, wiring must be changed according to the use. In this case, the power drive apparatus must be changed in the position according to the use, because the direction of connection of the power-source wires
10
was different between the input-terminal block
3
and the filter-input-terminal block
7
.
In order to overcome these problems of the separate-filter-type power drive apparatus, a filter-built-in-type power drive apparatus has been proposed.
As shown in
FIG. 9
, the filter-built-in-type power drive apparatus is provided with a filter circuit
13
including a choke coil
14
, a capacitor
15
, and the like mounted on a main circuit board
2
. The main circuit board
2
is received in the case
1
, thereby eliminating the filter unit
6
shown in FIG.
7
.
Referring to
FIG. 10
, in the known filter-built-in-type power drive apparatus, the filter circuit
13
is provided between an input terminal block
3
and a power module
18
, thereby suppressing the transmission of noise to a power source
11
from a switching device included in the power module
18
.
However, the known filter-built-in-type power drive apparatus must always contain the filter circuit
13
whether it is necessary or not. Although in Europe the suppression of noise is required by regulations, no filter is occasionally used in other regions. Consequently, unnecessary filter circuit
13
was mounted on the power drive apparatus in that case; as a result, the cost of the power drive apparatus was increased by an unnecessary component.
A known power drive apparatus has been proposed in, for example, Japanese Unexamined Patent Application Publication No. 8-308250, in which a filter unit is mounted on the power drive apparatus by applying a particular structure to an input terminal block of the power drive apparatus.
FIG. 11
is a perspective view of a power drive apparatus including an input terminal block having the particular structure disclosed in, for example, Japanese Unexamined Patent Application Publication No. 8-308250.
FIG. 12
is a sectional view of the power drive apparatus shown in
FIG. 11
, in which a filter unit is mounted.
A known power drive apparatus
301
is provided with heat-dissipating fins
311
at the bottom thereof, and a filter unit
303
a
is also provided with heat-dissipating fins
311
a
at the bottom thereof. An input terminal block
302
of the power drive apparatus
301
includes terminals R, S, and T connectable to a power source, terminals U, V, and W connectable to an external device, and a terminal G (grounding) connectable to the both sides. Each terminal of the input terminal block
302
is configured in a manner such that a pair of conductive flat springs
315
and
316
are supported, opposing to overlap each other, by an insulative member
313
at one end of each flat spring
315
or
316
, and the flat spring
315
is fixed to the insulative member
313
by a screw
314
so that the flat spring
315
is pressed to make contact with the flat spring
316
. The pair of flat springs
315
and
316
form a female terminal
305
. The other end of the flat spring
316
is connected to an interconnecting pattern
317
A of a substrate
317
included in the power drive apparatus
301
.
A filter unit
303
a
includes female terminals
305
a,
male terminals
304
a,
a substrate
325
a,
and a common mode reactor
310
a.
The female terminals
305
a
are formed on an end of the substrate
325
a,
and the male terminals
304
a
are formed on the other end of the substrate
325
a.
Each of the female terminals
305
a
is constituted by a pair of conductive contact parts
322
a
and
322
b,
and an insulative member
321
a
for fixing the contact parts
322
a
and
322
b.
A power-source wire
10
is electrically connected to the flat springs
315
which are pressed by the screws
314
. When the male terminals
304
a
are not inserted between the flat springs
315
and
316
, the flat springs
315
and
316
are connected with each other by being pressed by the screws
314
. An electrical current from the power source is supplied inside the power drive apparatus
301
through the flat springs
315
and
316
, and the interconnecting pattern
317
A.
The filter unit
303
a
is mounted on the power drive apparatus
301
by inserting the male terminals
304
a
between the flat springs
315
and
316
. As shown in
FIG. 12
, the electrical current from the power source is supplied inside the power drive apparatus
301
through the flat spring
315
, the upper face of the male terminal
304
a,
an interconnecting pattern
324
a
formed on the upper surface of the substrate
325
a,
the contact parts
322
a
and
322
b,
an interconnecting pattern
324
b
formed on the lower surface of the
Ichikawa Hiroki
Kajiura Goichi
Mitsubishi Denki & Kabushiki Kaisha
Patel Rajnikant B.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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