U.S. patent application number 13/379019 was filed with the patent office on 2012-04-26 for method for controlling electric compressor.
This patent application is currently assigned to DOOWON ELECTRONICS CO., LTD.. Invention is credited to In Hwe Koo, Geon Ho Lee, Jung Kyung Lee.
Application Number | 20120100012 13/379019 |
Document ID | / |
Family ID | 43356901 |
Filed Date | 2012-04-26 |
United States Patent
Application |
20120100012 |
Kind Code |
A1 |
Lee; Geon Ho ; et
al. |
April 26, 2012 |
METHOD FOR CONTROLLING ELECTRIC COMPRESSOR
Abstract
Disclosed is a method of controlling an electric compressor. The
method includes: (I) starting the electric compressor by applying
an electric power to an air conditioner; (II) determining, by an
inverter, whether the electric compressor is started normally; and
normally driving the electric compressor when the electric
compressor starts normally in the step (II) and determining again
whether the electric compressor starts normally by restarting the
electric compressor. Therefore, abnormal operation such as
malfunction, short, and overheating of the electric compressor is
detected in the early starting stage to determine restarting and
failure of starting the electric compressor so that reliability of
the electric compressor may be enhanced.
Inventors: |
Lee; Geon Ho; (Gyeonggi-do,
KR) ; Koo; In Hwe; (Gyeonggi-do, KR) ; Lee;
Jung Kyung; (Gyeonggi-do, KR) |
Assignee: |
DOOWON ELECTRONICS CO.,
LTD.
Asan-si, Chungcheongnam-do
KR
DOOWON TECHNICAL COLLEGE
Anseong-si, Gyeonggi-do
KR
|
Family ID: |
43356901 |
Appl. No.: |
13/379019 |
Filed: |
June 16, 2010 |
PCT Filed: |
June 16, 2010 |
PCT NO: |
PCT/KR2010/003855 |
371 Date: |
December 17, 2011 |
Current U.S.
Class: |
417/44.11 ;
417/44.1 |
Current CPC
Class: |
F25B 2500/06 20130101;
Y02B 30/70 20130101; F25B 49/025 20130101; F25B 2500/26 20130101;
F04B 49/06 20130101; Y02B 30/741 20130101; F04B 49/02 20130101;
F25B 2600/021 20130101; F24F 11/83 20180101 |
Class at
Publication: |
417/44.11 ;
417/44.1 |
International
Class: |
F04B 49/06 20060101
F04B049/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 19, 2009 |
KR |
10-2009-0054821 |
Jun 24, 2009 |
KR |
10-2009-0056417 |
Claims
1. A method of controlling an electric compressor comprising: (I)
starting the electric compressor by applying an electric power to
an air conditioner; (II) determining, by an inverter, whether the
electric compressor is started normally; and (III) normally driving
the electric compressor when the electric compressor starts
normally in the step (II) and determining again whether the
electric compressor starts normally by restarting the electric
compressor when the electric compressor does not start
normally.
2. The method of claim 1, wherein, after the step (III), the
electric compressor is driven normally when the electric compressor
starts normally and the step (III) is repeated by a preset times
when the electric compressor does not start normally.
3. The method of claim 2, wherein, when the electric compressor
does not starts normally even after repeating the step (III) by the
preset times, failure of starting of the electric compressor is
determined and an error message is outputted.
4. The method of claim 2, wherein a preset stand-by time for
restarting of the electric compressor is provided when the step
(III) is repeated.
5. The method of claim 2, wherein a starting current when the step
(III) is repeated is within Max .+-.25% of a driving current.
6. An electric compressor controlling method of detecting abnormal
operation of an inverter or a driving motor before starting the
electric compressor, comprising: (I) applying an electric power to
an air conditioner; (II) detecting currents of three phases by a
sensor by applying a minute current to the driving motor of the
electric compressor; and (III) determining the abnormal operation
of the inverter or the driving motor using sum of the three phase
currents (Ui+Vi+Wi).
7. The electric compressor controlling method of claim 6, wherein
the electric compressor is normally started or driven when the sum
of the three phase currents is 0 (zero) or within an error range
and it is determined that the inverter or the driving motor is
malfunctioned and an error message is outputted when the sum of the
three phase currents is not 0 (zero) or out of the error range.
8. The electric compressor controlling method of claim 6, wherein
the step (III) is carried out within 1 (one) second.
9. The electric compressor controlling method of claim 8, wherein
the sensor comprises a current sensor or a resistive sensor.
10. An electric compressor controlling method of detecting abnormal
operation of an inverter or a driving motor of an electric
compressor before starting the electric compressor, comprising: (I)
applying an electric power to an air conditioner; (II) detecting
two of three phase currents (Ui, Vi, and Wi) by a sensor by
applying a minute current to the driving motor of the electric
compressor; (III) calculating remaining one phase current from the
two phase currents; and (IV) determining whether the inverter or
the driving motor is operated abnormally by comparing the three
phase currents (Ui, Vi, and Wi) with a reference current.
11. The electric compressor controlling method of claim 10,
wherein, in the step (III), the remaining one phase current is
obtained from the two phase currents from the fact that sum of the
three phase currents (Ui+Vi+Wi) is 0 (zero).
12. The electric compressor controlling method of claim 11,
wherein, after the step (IV), the electric compressor is normally
started or driven when the three phase currents (Ui+Vi+Wi) are
within an error range of the reference current and the inverter or
the driving motor is determined as being malfunctioned and an error
message is outputted when the three phase currents (Ui+Vi+Wi) are
out of the error range of the reference current.
13. The electric compressor controlling method of claim 10, wherein
the step (IV) is carried out within 1 (one) second.
14. The electric compressor controlling method of claim 13, wherein
the sensor comprises a current sensor or a resistive sensor.
Description
TECHNICAL FIELD
[0001] The present invention relates to a method of controlling an
electric compressor, and more particularly to a method of
controlling an electric compressor such that abnormal operations of
the electric compressor such as malfunction, short, and overheating
are promptly detected by an inverter at early starting time of the
compressor to determine restarting of the electric compressor or
failure of starting of the electric compressor resulting in
improvement of reliability of the electric compressor.
BACKGROUND ART
[0002] In general, compressors applied to air conditioning systems
are divided into various types such as a reciprocating compressor,
a rotary compressor, and a scroll compressor according to the
operating types.
[0003] Furthermore, an electric compressor employing an electric
motor as a driving source includes a motor unit having a driving
motor and a compressor unit for compressing refrigerant.
[0004] In general, the electric compressor includes an inverter
installed at a side of a compressor housing to control revolutions
per minute of the driving motor for the variable control of air
conditioning efficiency of an air conditioning system when an
external load varies.
[0005] In more detail, the inverter includes a printed circuit
board (PCB) on which various circuit elements are mounted and is
disposed in an inverter housing provided at a side of the
compressor housing while being insulated by a cover for covering an
opening of the inverter housing.
[0006] However, the conventional electric compressor guarantees
stability by switching on/off a clutch at abnormal operation such
as malfunction, short, and overheating.
[0007] That is, in connection with the conventional electric
compressor, there is none of technology of detecting abnormal
operation of the electric compressor at the early start by the
inverter to determine whether to start the electric compressor
again or failure of start of the electric compressor.
[0008] Moreover, the conventional inverters are classified into a
sensor type inverter of controlling speed of a driving motor by
monitoring position of a rotor using a position sensor such as a
hall sensor, and a sensorless inverter of controlling speed of a
driving motor by estimating position of the rotor based on counter
electromotive force or current of the driving motor without a
position sensor. In recent, the sensorless inverter is
preferred.
[0009] However, the conventional sensorless inverter has difficulty
in detecting abnormal operation of a device of the inverter, short
between a motor and the inverter, and malfunction of the motor
early so that reliable operation may be deteriorated.
DISCLOSURE OF INVENTION
[0010] It is, therefore, an object of the present invention to
provide a method of controlling an electric compressor such that
abnormal operations of the electric compressor such as malfunction,
short, and overheating are promptly detected by an inverter at
early starting time of the compressor to determine restarting of
the electric compressor or failure of starting of the electric
compressor resulting in improvement of reliability of the electric
compressor.
[0011] It is another object of the present invention to provide a
method of controlling an electric compressor by detecting abnormal
operation of an inverter and malfunction and short of a motor
before starting of the electric compressor so that reliability may
be enhanced.
[0012] In accordance with an aspect of the present invention, there
is provided a method of controlling an electric compressor
including: (I) starting the electric compressor by applying an
electric power to an air conditioner; (II) determining, by an
inverter, whether the electric compressor is started normally; and
(III) normally driving the electric compressor when the electric
compressor starts normally in the step (II) and determining again
whether the electric compressor starts normally by restarting the
electric compressor when the electric compressor does not start
normally.
[0013] Preferably, after the step (III), the electric compressor is
driven normally when the electric compressor starts normally and
the step (III) is repeated by a preset times when the electric
compressor does not start normally.
[0014] Preferably, when the electric compressor does not starts
normally even after repeating the step (III) by the preset times,
failure of starting of the electric compressor is determined and an
error message is outputted.
[0015] Preferably, a preset standby time for restarting of the
electric compressor is provided when the step (III) is
repeated.
[0016] Preferably, moreover, a starting current when the step (III)
is repeated is within Max .+-.25% of a driving current.
[0017] In accordance with another aspect of the present invention,
there is provided an electric compressor controlling method of
detecting abnormal operation of an inverter or a driving motor
before starting the electric compressor, including: (I) applying an
electric power to an air conditioner; (II) detecting currents of
three phases by a sensor by applying a minute current to the
driving motor of the electric compressor; and (III) determining the
abnormal operation of the inverter or the driving motor using sum
of the three phase currents (Ui+Vi+Wi).
[0018] Preferably, the electric compressor is normally started or
driven when the sum of the three phase currents is 0 (zero) or
within an error range and it is determined that the inverter or the
driving motor is malfunctioned and an error message is outputted
when the sum of the three phase currents is not 0 (zero) or out of
the error range.
[0019] Preferably, the step (III) is carried out within 1 (one)
second.
[0020] Preferably, the sensor may be a current sensor or a
resistive sensor.
[0021] In accordance with still another aspect of the present
invention, there is provided an electric compressor controlling
method of detecting abnormal operation of an inverter or a driving
motor of an electric compressor before starting the electric
compressor, including: (I) applying an electric power to an air
conditioner; (II) detecting two of three phase currents (Ui, Vi,
and Wi) by a sensor by applying a minute current to the driving
motor of the electric compressor; (III) calculating remaining one
phase current from the two phase currents; and (IV) determining
whether the inverter or the driving motor is operated abnormally by
comparing the three phase currents (Ui, Vi, and Wi) with a
reference current.
[0022] Preferably, in the step (III), the remaining one phase
current is obtained from the two phase currents from the fact that
sum of the three phase currents (Ui+Vi+Wi) is 0 (zero).
[0023] Preferably, after the step (IV), the electric compressor is
normally started or driven when the three phase currents (Ui+Vi+Wi)
are within an error range of the reference current and the inverter
or the driving motor is determined as being malfunctioned and an
error message is outputted when the three phase currents (Ui+Vi+Wi)
are out of the error range of the reference current.
[0024] Preferably, the step (IV) is carried out within 1 (one)
second.
[0025] Preferably, the sensor may be a current sensor or a
resistive sensor.
EFFECT OF THE INVENTION
[0026] According to the method of controlling an electric
compressor in accordance with the present invention, abnormal
operations such as malfunction, short, and overheating of the
electric compressor can be detected by an inverter at the early
starting time of the electric compressor to determine restarting of
the electric compressor or failure of starting the electric
compressor so that reliability of the electric compressor may be
enhanced.
[0027] Moreover, three phase currents of the driving motor are
measured by a sensor before starting the electric compressor such
that abnormal operation of the inverter and malfunction or short of
the motor can be determined promptly.
[0028] In other words, stable operation of the inverter may be
achieved and troubleshooting of the driving motor can be detected
in early stage so that accident may be prevented.
BRIEF DESCRIPTION OF DRAWINGS
[0029] The above and other objects and features of the present
invention will become apparent from the following description of
embodiments given in conjunction with the accompanying drawings, in
which:
[0030] FIG. 1 is a sectional view schematically illustrating an
electric compressor used in the present invention;
[0031] FIG. 2 is a flowchart illustrating a method of controlling
an electric compressor according to an exemplary embodiment of the
present invention;
[0032] FIG. 3 is a flowchart illustrating a method controlling an
electric compressor according to another exemplary embodiment of
the present invention; and
[0033] FIG. 4 is a flowchart illustrating a method controlling an
electric compressor according to still another exemplary embodiment
of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0034] Hereinafter, embodiments of the present invention will be
described in detail with reference to the accompanying
drawings.
[0035] FIG. 1 is a sectional view schematically illustrating an
electric compressor used in the present invention. FIG. 2 is a
flowchart illustrating a method of controlling an electric
compressor according to an exemplary embodiment of the present
invention.
[0036] FIG. 3 is a flowchart illustrating a method controlling an
electric compressor according to another exemplary embodiment of
the present invention.
[0037] FIG. 4 is a flowchart illustrating a method controlling an
electric compressor according to still another exemplary embodiment
of the present invention.
[0038] Before description of the method of controlling an electric
compressor according to an exemplary embodiment of the present
invention, an electric compressor will be described for better
understanding of the present invention.
[0039] As illustrated in FIG. 1, an inverter 100 is mounted at a
side of an electric compressor according to an exemplary
embodiment.
[0040] The electric compressor is an element of an air conditioner
and has a driving shaft rotated not by a driving force transmitted
from a power generating device such as an engine but by a driving
motor mounted in a compressor housing.
[0041] That is, the electric compressor includes a compressor unit
200 provided with devices for compressing refrigerant therein and a
driving unit 300 having a driving motor for driving the compressor
unit. The inverter 100 is installed in an inverter housing 500
which is provided at an outer circumference of the compressor
housing, near a side where the driving motor is disposed,
specifically on a side of the outer circumference, and an upper
opening of which is covered by a cover 400.
[0042] In this case, the inverter 100 performs variable control of
revolutions per minute (RPM) of the driving motor to adjust flow
rate of refrigerant circulating by the refrigerating cycle of an
air conditioner and is electrically connected to the driving motor
by a terminal or a bus bar.
[0043] The inverter 100 includes a printed circuit board (PCB) on
which various circuit devices such as an MCU having an IC on which
an inverter operating program is stored, an intelligent power
module (IPM) on which an insulated gate bipolar transistor (IGBT)
or a motor drive function is loaded, a regulator, an inductor, a
capacitor, etc., are mounted.
[0044] The inverter 100 has a function of determining failure of
starting an electric compressor to enhance reliability of the
electric compressor.
[0045] In addition, the inverter 100 may be a sensorless inverter
estimating position of a rotor based on counter electromotive force
and current of the driving motor without a position sensor to
control RPM of the driving motor.
[0046] The sensorless inverter includes sensors detecting position
of the rotor before starting of the compressor wherein the sensor
are installed to three phases U, V, and W of the three phase
driving motor to measure currents. Here, the sensors may be current
sensors or resistive sensors.
[0047] Thus, the sensors measure currents of three phases such that
abnormal operation of the inverter and malfunction or short of the
motor are determined at early stage so that reliability may be
enhanced.
[0048] Hereinafter, the method of controlling an electric
compressor will be described in detail with reference to the
accompanying drawings.
[0049] Exemplary Embodiment 1
[0050] As illustrated in FIG. 2, according to a method of
controlling an electric compressor according to an exemplary
embodiment of the present invention to determine whether the
electric compressor is failed to start, an electric power is
applied to a temperature controller such as an FATC (S110).
[0051] Next, revolutions of the driving motor are assigned to start
the electric compressor (S120 and S130).
[0052] Then, the inverter determines whether the electric
compressor starts normally (S140).
[0053] That is, the inverter determines whether there is abnormal
operation of the compressor such as malfunction, short, and
overheating at the early start of the electric compressor. The
electric compressor is driven normally when the electric compressor
is started normally (S150) while the following step (S160) is
carried out when the electric compressor is not started
normally.
[0054] Next, the electric compressor is restarted to determine
whether the electric compressor is started (S160).
[0055] That is, the electric compressor is driven normally when the
electric compressor is started normally (S150) or the step (S160)
is repeated by a preset times when the electric compressor is not
started normally (S170 and S180).
[0056] In this case, the repetition times may be 5 (five).
[0057] Meanwhile, when the step of restarting the electric
compressor (S160) is repeated, there is a standby time (S190).
[0058] The stable starting of the electric compressor is enabled by
stand by until pressure difference between intake and discharge is
reduced, wherein the standby time may range from 0 (zero) to 5
(five) seconds.
[0059] Moreover, the starting current in the step of restarting the
electric compressor (S160) maintains Max .+-.25% of drive current
(S200).
[0060] When the electric compressor is not started normally even
after the step (S160) is repeated by the preset times, this case is
determined failure of starting the electric compressor, an error
message is output, and all processes are ended (S210 and S220).
[0061] Exemplary Embodiment 2
[0062] As illustrated in FIG. 3, according to a method of
controlling an electric compressor according to this exemplary
embodiment of the present invention to determine abnormal operation
of an inverter and malfunction and short of a motor, an electric
power is applied to an air conditioner (S210).
[0063] Next, a minute current is applied to a driving motor of the
electric compressor to measure currents of three phases Ui, Vi, and
Wi (S220).
[0064] With the three phase currents Ui, Vi, and Wi measured in
step 5220, whether the inverter and the driving motor are abnormal
is determined (S230).
[0065] In this case, the inverter or the driving motor is
determined normal such that the electric compressor is started
normally when sum of the three phase currents Ui+Vi+Wi is 0 (zero)
or within an error range (S240). Otherwise, when the sum of three
phase currents Ui+Vi+Wi is out of the error range, the inverter or
the driving motor is determined to be malfunctioned (S250).
[0066] Specifically, in a three phase driving motor, the sum of
three phase current is 0 (zero) as expressed by the following
equation 1.
[0067] Thus, when wrong measured currents Ui, Vi, and Wi are
provided by abnormal operation of the inverter and malfunction or
short of the motor, the sum of the wrong measured currents cannot
be 0 (zero) so that the inverter or the driving motor is determined
as being malfunctioned.
[0068] Meanwhile, the step S230 may be carried out within 1 (one)
second such that responsibility of starting of a compressor may be
improved.
[Equation 1]
U.sub.i+V.sub.i+W=0
[0069] Next, after the step S250, an error message is outputted to
stop the electric compressor (S160).
[0070] Exemplary Embodiment 3
[0071] As illustrated in FIG. 4, according to a method of
controlling an electric compressor according to this exemplary
embodiment of the present invention to determine abnormal operation
of an inverter and malfunction and short of a motor, an electric
power is applied to an air conditioner (S310).
[0072] Next, a minute current is applied to a driving motor of the
electric compressor to measure two of the three phase currents Ui,
Vi, and Wi (S320).
[0073] The remaining one phase current is calculated from the
measured two phase currents (S330).
[0074] In this case, since sum of the three phase currents Ui+Vi+Wi
is 0 (zero) as expressed by equation 1, the remaining one phase
current is calculated.
[0075] Each of the three phase currents Ui, Vi, and Wi is compared
with a reference current to determine abnormal operation of the
inverter and the driving motor (S340).
[0076] In this case, when each of the three phase currents Ui, Vi,
and Wi is within an error range of the reference current, the
electric compressor is started normally (S350). Otherwise, when the
three phase currents Ui, Vi, and Wi are out of the error range of
the reference current, the inverter or the driving motor is
determined as being malfunctioned (S360).
[0077] In specifically, the reference current is currents of the
three phases measured at the normal starting of the electric
compressor. Thus, when the three phase currents Ui, Vi, and Wi
measured and calculated in the step are out of the error range of
the reference current, the inverter or the driving motor is
determined as being malfunctioned.
[0078] Meanwhile, the step S340 may be carried out within 1 (one)
second so that reliability of the electric compressor may be
improved.
[0079] After step S360, an error message is outputted to stop the
electric compressor (S370).
[0080] While the invention has been shown and described with
respect to the preferred embodiments, it will be understood by
those skilled in the art that various changes and modifications may
be made without departing from the spirit and scope of the
invention as defined in the following claims.
* * * * *