Electric power conversion systems – Current conversion – With condition responsive means to control the output...
Reexamination Certificate
1999-11-23
2001-07-17
Bowers, Charles (Department: 2813)
Electric power conversion systems
Current conversion
With condition responsive means to control the output...
Reexamination Certificate
active
06262902
ABSTRACT:
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT
The present invention relates to a semiconductor device and in particular, to a power conversion component built in an electric conversion apparatus, such as general inverter apparatus, numerically controlled machine tool, or air conditioner.
In general, an inverter apparatus that is applied to a variable-speed device for a motor is composed of a power element for electric conversion, a drive circuit for controlling and driving the power element, a protection circuit, and a control circuit for generally controlling these components. A power conversion device having a semiconductor device called “intelligent power module” (hereafter referred to as “IPM”) has been commercially available, and is formed of an integrated package including, in the above components, the power element for converting a direct current into an alternate current, the drive circuit, and the protection circuit.
FIG. 10
is a block diagram showing a configuration of a circuit in a conventional inverter apparatus. The inverter apparatus is composed of a converter
1
connected to a two- or three-phase alternate power supply to convert an alternate current into a direct current; an electrolytic capacitor
2
for smoothing; an IPM
3
; a control circuit formed of a central processing unit
6
(CPU.ROM) including a buffer
4
, a controller
5
, and a memory; a power supply circuit for the IPM
3
and control circuit, formed of a switching transistor
7
, transformers
8
,
9
, and a switching regulator
10
; and a current transformer CT installed between an output of the IPM
3
and a motor M.
The IPM
3
is integrally composed of a three-phase inverter
11
composed of a power element and providing an output connected to the motor M; a predriver
12
for controlling and driving the inverter
11
; a protect circuit
13
; a sensor
14
for detecting an overcurrent; a sensor
15
for detecting overheating; a braking power element
16
and a resistor
17
that are used to provide deceleration control for the motor M; and a predriver
18
for controlling and driving the braking power element
16
.
A control signal from the control circuit to the IPM
3
is supplied from the buffer
4
to the predrivers
12
,
18
via a photocoupler, and an alarm signal issued when the sensor
14
or
15
detects an overcurrent or overheated condition is supplied from the protect circuit
13
to the buffer
4
via the photocoupler. In addition, an output from the current transformer CT is connected to the controller
5
.
The current transformer CT detects an output current flowing from the IPM
3
to the motor M in order to return this current to the controller
5
for various controls. The current transformer CT has three through-holes therein, and is provided in the inverter apparatus in such a manner that wires or bars that act as output-current lines from the inverter
11
are inserted through these through-holes.
In the inverter apparatus with the configuration as described above, a direct voltage converted by the converter
1
is converted by the inverter
11
into an alternate voltage supplied to the motor M. In the inverter
11
, bridges are assembled by using IGBTs (Insulated Gate Bipolar Transistors) and diodes, and the IGBTs chopping-control a direct current to allow an alternate current to consequently flow through the motor. By varying the frequency of this alternate current, the rotational speed of the motor can be varied.
In addition, an inverter output current detected by the current transformer CT is input to the controller
5
, which controls such that the waveform of the output current will not be distorted or the output voltage does not exceed a predetermined value.
FIG. 11
is a block diagram showing a power conversion circuit in a conventional inverter apparatus. The power conversion circuit is composed of two modules, that is, the converter
1
and the IPM
3
including the inverter
11
. Module terminals
21
to
25
, which are shown by a circle, are provided for the converter
1
as I/O terminals, and module terminals
26
to
30
are provided for the IPM
3
. In addition, terminal blocks R, S, T, P
1
, P
2
, N, U, V and W, which are shown by large black circles, are provided as I/O terminals for the converter
1
and inverter apparatus including the IPM
3
.
The module terminals
21
to
30
of the converter
1
and IPM
3
are connected to the corresponding terminal blocks, and these connections are carried out by, for example, screwing copper bars to the blocks. The connections between the converter
1
and the inverter
11
, that is, the connections between the terminal blocks P
1
and P
2
and between the module terminals
25
and
27
are also carried out by screwing copper bars to the blocks.
However, the current transformer built into the conventional inverter apparatus to monitor an output current is relatively larger than the other components and thus requires a large installation space, thereby hindering the development of more compact inverter apparatuses. In addition, since the wires or bars acting as output current lines must be inserted through the current transformer, the number of assembly steps is so large that the process becomes complicated.
In addition, since the module terminals and the terminal blocks are connected together by screwing the wire rods, such as copper bars, the apparatus requires a large number of set screws for connections, a complex wiring pattern, and a large number of assembly steps. In addition, an installation space must be provided for the wiring, and this constitutes a constraint on space-saving efforts.
The present invention has been made in view of these problems, and an object of the invention is to provide a power conversion component that can reduce a space for the incorporated devices and that can reduce requirements for both wiring space and the number of assembly steps.
Further objects and advantages will be apparent from the following description of the invention
SUMMARY OF THE INVENTION
In order to solve the above-noted problems, the present invention provides a power conversion component comprising a power semiconductor element, a drive circuit, and a protection circuit that are integrated into the same package, wherein the component further comprises a shunt resistor provided in series with output lines from the power semiconductor element to detect an output current; and control pins that can be drawn from both ends of the shunt resistor through a wiring pattern and connected to an external device.
According to such a power conversion component, the output current can be output to an external device through the control pins as the end-to-end voltage of the shunt resistor. This configuration enables the output current to be detected without a separate current transformer requiring a large installation space, thereby reducing a required space for the apparatus into which this power conversion component is integrated.
In addition, the present invention provides a power conversion component comprising a power semiconductor element, a drive circuit, and a protect circuit that are integrated into the same package, wherein at least some of module terminals connected to a main circuit of the power semiconductor element are configured as terminal blocks of an apparatus into which this power conversion component is integrated.
According to such a power conversion component, the module terminals of the power conversion component are integrated with the terminal blocks of the apparatus into which this power conversion component is integrated, thereby eliminating the need for the wire rods and set screws for connections used to connect the module terminals and terminal blocks. As a result, both the wiring space and the number of assembly steps can be reduced.
REFERENCES:
patent: 3676807 (1972-07-01), Boer
patent: 5543659 (1996-08-01), Hosen
Ferreira et al., “Integration of High Frequency Current Shunts in PowerElectronic Circuits”, Jul. 1992, Power Electronics Specialists Conference, 1992. Record., 23rd Annua
Oda Yoshinori
Watanabe Manabu
Bowers Charles
Fuji Electric & Co., Ltd.
Kanesaka & Takeuchi
Pert Evan
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