Electricity: motive power systems – Limitation of motor load – current – torque or force
Reexamination Certificate
1999-11-04
2001-05-15
Ro, Bentsu (Department: 2837)
Electricity: motive power systems
Limitation of motor load, current, torque or force
C388S903000
Reexamination Certificate
active
06232734
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a power module having a self protection function. The term “power module” as used herein means a unit comprising power elements such as power transistors and other function, for example, a control unit stored in a single package.
Heretofore, there has been known an intelligent power module as a power module having a self protection function. The term “intelligent power module” (to be simply referred to as “power module” hereinafter) as used herein generally means a module comprising power elements such as power transistors and a control unit for driving and controlling the power elements stored in a single package.
For instance, a prior art power module
2
disclosed by Japanese Laid-open Patent Application No. 10-267977 and shown in
FIG. 4
comprises power elements
4
for driving a motor
1
, power element drive means
3
for driving and controlling the power elements
4
and self protection means
5
having a self protection function.
The self protection means
5
protects the power module
2
from a plurality of predetermined abnormal phenomena and outputs an abnormality detection signal to the outside when it detects an abnormal phenomenon.
The power element drive means
3
drives and controls the power elements
4
based on a drive signal from an external unit and the output of the self protection means
5
.
As shown in
FIG. 5
, the self protection means
5
comprises an overcurrent protection circuit
51
for protecting the power elements
4
, for example, when a current higher than a predetermined current value runs through the power elements
4
incorporated in the power module
2
, a short-circuit protection circuit
52
for protecting the power elements
4
or a circuit connected to the power elements
4
when a short-circuit accident occurs in the power elements
4
, a control power voltage drop protection circuit
53
for protecting the power module
2
when a control power voltage supplied to the power module
2
falls, an excessive temperature protection circuit
54
for protecting the module from an excessive temperature in the power module
2
, and a decoder
55
for decoding binary signals from the above protection circuits
51
to
54
to generate an abnormality detection signal and supplying it to a plurality of output terminals F
1
to F
3
as a binary signal.
That is, the protection circuits
51
to
54
are incorporated in the power module
2
to cope with a plurality of predetermined abnormal phenomena, and the self protection means
5
outputs an abnormality detection signal to the external unit through the output terminals FOI to FO
3
when the protection circuit
51
to
54
fulfill their self protection functions.
When the plurality of the protection circuits
51
to
54
fulfill their functions independently, a protection circuit fulfilling its function is identified by an abnormality detection signal and reported. When two or more protection circuits fulfill their functions at the same time to cope with a plurality of abnormal phenomena which occur at the same time, they are reported with abnormality detection signals at a time.
SUMMARY OF THE INVENTION
The plurality of protection circuits provided to cope with a plurality of predetermined abnormal phenomena are each composed of hardware, and decision values for detecting the abnormal phenomena are fixed at design values which takes into consideration differences in the power elements
4
.
Therefore, the above decision values include a great margin, which makes the operation range of each of the power element
4
narrower than the actual range, thereby making impossible the effective use of the operation range of the power element
4
.
It is an object of the present invention which has been made to solve the above problem to provide a power module which enables the effective use of the operation range of each power element.
The power module having self protection means according to the present invention comprises decision value storage means for storing decision values for the detection of a plurality of predetermined abnormal phenomena by the self protection means and information transmission means for receiving decision values set by an external unit, outputting the decision values to the decision value storage means and outputting the decision values stored in the decision value storage means to external unit.
The power module comprises power elements for driving a motor, self protection means provided to protect the power module from a plurality of predetermined abnormal phenomena, information transmission means for receiving information from an external unit and outputting information to the external unit, information storage means for storing information from the external unit input by the information transmission means, motor control means for generating a motor control signal based on a control instruction from the external unit and the output of the self protection means, and power element drive means for driving and controlling the power elements based on a motor control signal from the motor control means and the output of the self protection means and serves as a motor controller for controlling various types of motors.
The above information transmission means is an interface circuit for receiving decision values for the detection of a plurality of predetermined abnormal phenomena by the self protection means as information from the external unit and information on the control of the motor such as motor control algorithms and algorithms for judging the abnormality of the power elements and outputting this information to the external unit, and a control program for the control of the motor can be set and changed in addition to the decision values.
A plurality of the information transmission means are provided for communication between modules and used as interface circuits having a communication system for at least one of external units having different communication protocols to enable communication with the external units having different communication protocols.
The above motor control means outputs an alarm to the external unit based on the output of the self protection means.
The above and other objects, features and advantages of the invention will become more apparent from the following description when taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 5063338 (1991-11-01), Capel et al.
patent: 5497289 (1996-03-01), Sugishima et al.
patent: 5577890 (1996-11-01), Nielsen et al.
patent: 5610493 (1997-03-01), Wieloch
patent: 9-51068 (1997-02-01), None
patent: 10-267977 (1998-10-01), None
Mitsubishi Denki & Kabushiki Kaisha
Ro Bentsu
Sughrue Mion Zinn Macpeak & Seas, PLLC
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