Control apparatus and method for actuating an electrically driven
Contents
1. 62 126 125 127 detected temperature Ts is higher than the upper limit Ta 62 129 259 2 244 208 209 161 228 1 A 228 4 228 5 230 165 80 2 80 3 80 4 micro computer 6 sets a modified output W1 smaller than 104 33 257 721 722 714 361 690 694 target output WO by a predetermined correction value AW 695 720 722 699 717 W1 W0 AW gt 0 and adjusts the output command W to the modified output W1 Then the compressor 11 is actuated 56 References Cited based on thus obtained output command W U S PATENT DOCUMENTS f 4 720 981 1 1988 Helt et al 62 2284 X 14 Claims 13 Drawing Sheets 15 SMALL 3 LARGE OFF U S Patent Jul 29 1997 Sheet 1 of 13 5 651 260 c9 lt lt CD U S Patent Jul 29 1997 Sheet 2 of 13 5 651 260 FIG 2A FIG 2B OUTPUT F UPPER LIMIT POWER CONSUMPTION INNER TEMP OUTPUT POWER CONSUMPTION FIG 2 FIG 2D OUTPUT J OUTPUT H INNER TEMP OUTPUT I INNER TEMP OUTER TEMP COOLING ABILITY U S Patent Jul 29 1997 Sheet 3 of 13 5 651 260 FIG 5 SENSOR TEMP TIME COMPRESSOR OUTPUT TIME U S Patent Jul 29 1997 Sheet 4 of 13 5 651 260 FIG 4 READ MANUAL SW 51 SIGNAL Sm S 2 S6 STOP COMPRESSOR END SET MODIFIED OUTPUT WO DRIVE COMPRESSOR BY TARGET OUTPUT W 0 DRIVE COMPRESSOR BY REDUCED OU2. a constant value it is desirable to increase the reduction amount AW in accordance with the difference between 5 651 260 9 sensor temperature Ts and allowable upper limit i e AWz k1 Ts Ta as shown a solid line in FIG 6 Using such setting it becomes possible to eliminate sudden changes of the compressor output as well as to suppress the overshoot of the sensor temperature Ts Furthermore it is also desirable to increase the reduction amount AW in accordance with the time deviation of the difference between sensor temperature Ts and allowable upper limit Ta in addition to the difference itself i e AW k1 Ts Ta k2 A Ts Ta At as shown by an alternate long and dash line in FIG 6 Using such setting it becomes possible to further quicken the convergence of sensor tem perature Ts Next a modified operation of the present invention will be explained with reference to FIG 7 which shows another control routine performable by the control system for actu ating the compressor in accordance with the present inven tion The control routine shown in FIG 7 is different from that of FIG 4 in that some hysteresis is provided in the setting of allowable range More specifically in step S11 micro computer 6 reads manual switch signal Sm from the operating section 15 the manual switch signal Sm representing the user s request entered through manipulation of the slidable knob provided on the operating section 15 N
3. accordance with the present invention When the flag F is 0 i e NO in step S17 the control routine proceeds to step S18 On the contrary when the flag F is 1 i e YES in step S17 the control routine proceeds to step S19 In step S18 micro computer 6 makes a judgement as to whether the sensor temperature Ts is larger than predeter mined upper limit temperature Ta When the sensor temperature Ts is not larger than the upper limit temperature Ta the control routine proceeds to Step 520 to set the output command W to the target output WO obtained in step 513 W W0 and send this command to the compressor 11 thereby driving the compressor 11 in direct proportion to the user s request After completing step S20 flag F is set to 0 i e 0 and the control routine returns to step S11 to repeat the above described processing 10 15 20 25 30 35 45 50 55 65 10 On the other hand when the sensor temperature Ts is larger than the upper limit temperature Ta YES in step S18 micro computer 6 proceeds to step S22 to set a modified output W1 which is smaller than the target output WO by AW W1 W0 AW gt 0 Subsequently in step S23 micro computer 6 sets the output command W to the modified output W1 W W 1 and sends this command to the compressor 11 thereby driving the compressor 11 at a slightly smaller output compared with the user s request In other words the sensor tem
4. by the temperature sensing means exceeds the upper limit And the drive means actuates the compressor based on the output command generated from the command generating means Yet further a fourth aspect of the present invention provides a control apparatus for actuating an electrically driven compressor equipped in an automotive vehicle char acterized by manual switch means target output means temperature sensing means modified output means emer gency means command generating means and drive means According to the fourth aspect compressor control apparatus the manual switch means allows a use to adjust an output of the compressor and generates a request signal representing a quantity of user s manual adjustment The target output means receives the request signal from the manual switch means and obtains a target output of the compressor which is proportional to the quantity of user s manual adjustment The temperature sensing means generates a temperature signal representing a temperature of a component in the control apparatus The modified output means receives the temperature signal from the temperature sensing means and obtains a modified output when the temperature detected by the temperature sensing means exceeds a predetermined upper limit The modified output is set smaller than the target output obtained by the target output means but larger than 0 The emergency means receives the temperature signal from the tempe
5. invention FIGS 2A through 2D are views showing the correlations among temperature output power consumption and cool ing ability in the electric compressor control system FIG 3 is a circuit block diagram showing the control system for the electrically driven compressor in accordance with the present invention FIG 4 is a flow chart showing a control routine performed by the control system for actuating the compressor in accordance with the present invention FIG 5 is a time chart showing an output control of the electric compressor in relation to a detected temperature in accordance with the present invention FIG 6 is a time chart showing another output control of the electric compressor in relation to a detected temperature in accordance with the present invention FIG 7 is a flow chart showing another control routine performed by the control system for actuating the compres sor in accordance with the present invention FIG 8 is a time chart showing an output control of the electric compressor in relation to a detected temperature in accordance with the present invention FIGS 9A through 9C are views showing schematic arrangements of a control system for an electrically driven compressor in accordance with a second embodiment of the present invention FIG 10 is an arrangement of a control system for an electrically driven compressor in accordance with a third embodiment of the present invention FIG 11 is an arrangeme
6. the prior art the present invention has a principal object to provide a control apparatus and a method for actuating an electric compressor used in an air conditioning system which is capable of promptly and adequately suppressing the 10 15 20 25 30 35 45 50 55 65 2 output of the compressor in response to a detected increase of the inside or peripheral temperature of the control system thereby stabilizing the operation of the compressor and assuring reliability of the air conditioning system for an automotive vehicle To accomplish above and other related objects a first aspect of the present invention provides a control apparatus for actuating an electrically driven compressor equipped in an automotive vehicle comprising a temperature sensor generating a signal representing a temperature of a compo nent in the control apparatus and control means connected to the temperature sensor for adjusting an output command supplied to the electrically driven compressor in accordance with the signal generated from the temperature sensor According to features of the preferred embodiments the temperature sensor detects a temperature of any one of a heat radiator such as a heat sink a micro computer or like processing unit a relay a switching power unit and an electrolytic capacitor substantially determining the life of the control system In addition it is possible to provide an alarm indicator generating an
7. when said temperature detected by said temperature sensing means exceeds a predetermined upper limit value said modified output command being smaller than said output command but larger than 0 9 A control apparatus for actuating an electrically driven compressor equipped in an automotive vehicle comprising manual switch means for allowing a use to adjust an output of said compressor and generating a request signal representing a quantity of user s manual adjust ment target output means for receiving said request signal from said manual switch means and obtaining a target output of said compressor said target output being propor tional to said quantity of user s manual adjustment temperature sensing means for generating a temperature signal representing a temperature of a component in the control apparatus modified output means for receiving said temperature signal from said temperature sensing means and obtain ing a modified output when said temperature detected by said temperature sensing means exceeds a predeter mined upper limit said modified output being smaller than said target output obtained by said target output means but larger than 0 command generating means for generating an output command supplied to said compressor in such a manner that said output command is equalized to said target output when said temperature detected by said tem perature sensing means is within a predetermined allowable range while said outp
8. 2C an upper limit of an outer temperature corresponding to the upper limit of the inner temperature can be identified in a one to one manner when the output of the compressor 11 is known For example when the outer temperature is C the corre sponding inner temperature will exceeds the upper limit when the compressor 11 is driven at the output H but will be identical with the upper limit when the compressor 11 is driven at the output L Thus measuring an outer temperature makes it possible to indirectly detect the corresponding inner temperature Furthermore according to the correlation shown in FIG 2B when the electric power consumption is increased from to A the inner temperature will exceed the upper limit if the compressor 11 is driven at the output F Hence the output of compressor 11 needs to be reduced to the level of output G where the inner temperature is identical with the upper limit Next an operation of the present invention will be explained with reference to FIG 4 which shows a control routine performed by the control system for actuating the compressor in accordance with the present invention First in step S1 micro computer 6 reads a manual switch signal Sm from the operating section 15 since the manual switch signal Sm represents a user s request entered through manipulation of the slidable knob provided on the operating section 15 Next in step S2 micro computer 6 makes a judgement as t
9. 5 is a time chart showing a change of compressor output in relation to a detected temperature in accordance with the present invention As shown in FIG 5 the output command W of the compressor 11 is reduced from W0 to W1 when the sensor temperature Ts exceeds the allowable upper limit tempera ture Ta The micro computer 6 maintains the output com mand W at a constant value W1 for a while unless the sensor temperature Ts exceeds the critical temperature Tb Steps S4 SS S7 S9 and S10 of FIG 4 In the event the sensor temperature Ts accidentally reaches the critical temperature Tb as shown by an alternate long and two dashes line in FIG 5 micro computer 6 immediately changes the output com mand W to 0 so as to forcibly stop the compressor 11 Steps S5 and S6 of FIG 4 On the other hand when the increase of sensor tempera ture Ts is relatively moderate as shown by a solid line in FIG 5 micro computer 6 continues to drive compressor 11 at the reduced output W1 until the sensor temperature Ts falls below the allowable upper limit temperature Ta Once the sensor femperature Ta falls within the allowable range micro compressor 6 restores the output command W to the target output WO so as to drive the compressor 11 in accordance with the user s request i e in direct proportion to the manipulation volume of the knob slidable on the operating section 15 Steps 51 55 S7 and 58 of FIG 4 Although FIG 5 shows the reduction amount AW as
10. TPUT W WI U S Patent Jul 29 1997 Sheet 5 of 13 5 651 260 FlG 6 CASE 1 1 Ts SENSOR CASE 2 AW kl Ts TEMP k2 A Ts Ta At TIME COMPRESSOR OUTPUT TIME U S Patent Jul 29 1997 Sheet 6 of 13 5 651 260 FIG 7 READ MANUAL SW 511 SIGNAL Sm N 513 OUTPUT WO 516 STOP COMPRESSOR SET MODIFIED OUTPUT W1 Wi WO DRIVE COMPRESSOR BY DRIVE COMPRESSOR BY REDUCED OUTPUT TARGET OUTPUT W WI W WO U S Patent Jul 29 1997 Sheet 7 of 13 5 651 260 FIG 8 SENSOR TEMP TIME COMPRESSOR OUTPUT TIME U S Patent Jul 29 1997 Sheet 8 of 13 5 651 260 lt Aa FIG 9A U S Patent Jul 29 1997 Sheet 9 of 13 5 651 260 un tu lt CC lt lt gt FIG 10 U S Patent Jul 29 1997 Sheet 10 of 13 5 651 260 Lun c lt lt N FIG 11 U S Patent Jul 29 1997 Sheet 11 of 13 5 651 260 Ln p lt lt l lt e FlG 12 U S Patent Jul 29 1997 Sheet 12 of 13 5 651 260 un e CC lt FlG 13 U S Patent Jul 29 1997 Sheet 13 of 13 5 651 260 3 Lu lt lt lt gt 5 651 260 1 CONTROL APPARATUS AND METHOD FOR ACTUATING AN ELECTRICALLY DRI
11. US005651260A United States Patent 11 Patent Number 5 651 260 Goto et al 43 Date of Patent Jul 29 1997 54 CONTROL APPARATUS AND METHOD FOR 5 481 433 1 1996 Carter 165 80 3 X ACTUATING AN ELECTRICALLY DRIVEN 5 493 868 2 1996 Kikuiri et al 62 129 COMPRESSOR USED IN AN AIR CONDITIONING SYSTEM OF AN AUTOMOTIVE VEHICLE Primary Examiner Harry B Tanner 75 Inventors Naomi Goto Shiga ken Makoto Agen oh Firm IESUS Associates Yoshida Kusatsu both of Japan 57 ABSTRACT US Assignee prions computer 6 reads manual switch signal Sm from an operating section 15 and sets a target output W0 of an 21 Appl No 605 272 electrically driven compressor 11 based on the manual 22 Filed Feb 6 1996 switch signal Sm A temperature sensor 20 detects a tem Aro 2 perature Ts of a designated component in the compressor 30 Foreign Application Priority Data control system Micro computer 6 judges whether the Feb 9 1995 JP Japan 7 021894 detected temperature Ts is larger than a predetermined upper UL R a u a F25B 49 02 limit Ta and generates an output command W equalized to 521 US CL ee 62 126 62 228 4 62 259 2 the target output WO when the temperature Ts is within a 165 80 4 predetermined allowable range On the other hand when the 58 Field of Search
12. VEN COMPRESSOR USED IN AN AIR CONDITIONING SYSTEM OF AN AUTOMOTIVE VEHICLE BACKGROUND OF THE INVENTION 1 Field of the Invention The present invention generally relates to a control appa ratus and a method for actuating an electrically driven compressor used in an air conditioning system of an auto motive vehicle which is capable of promptly and adequately adjusting the output of the compressor in response to a detected increase of the inside or peripheral temperature of the control system thereby stabilizing the operation of the compressor and assuring reliability of the air conditioning system 2 Prior Art A control system of an electric compressor is generally subjected to heat generation due to power consumption when it actuates the compressor For example an electrically driven compressor when it has an output of 2 KW will cause a heat generation of approximately 40 W which corresponds to 246 of the overall output Various electronic components inside the control system are sensitive to heat thus it is essentially important to protect these electronic components for guaranteeing the performance of the control system To this end the control system is generally provided with a heat radiation device of normally an air cooling type or a water cooling type Specifications of the heat radiation device needs to be designed based on the heat radiation conditions including ambient or peripheral temperatures and electric power con
13. alarm Whenever the temperature detected by the temperature sensor goes out of a predetermined allow able range Furthermore a second aspect of the present invention provides a control apparatus for actuating an electrically driven compressor equipped in an automotive vehicle char acterized by manual switch means command generating means drive means temperature sensing means and adjust ing means According to the second aspect compressor control apparatus the manual switch means allows a use to adjust an output of the compressor and generates a request signal representing a quantity of user s manual adjustment The command generating means receives the request signal and generates an output command supplied to the compressor in accordance with the quantity of manual adjustment The drive means actuates the compressor based on the output command The temperature sensing means generates a temperature signal representing a temperature of a com ponent in the control apparatus And the adjusting means receives the temperature signal from the temperature sensing means and generates a modified output command when the temperature detected by the temperature sensing means exceeds a predetermined upper limit value In this case the modified output command is smaller than the output com mand but larger than 0 Still further a third aspect of the present invention pro vides a control apparatus for actuating an electrically driven compressor
14. ctrically driven compressor in accordance with a first embodiment of the present invention The control unit 1 comprises a printed circuit board 3 on which micro computer 6 relay 7 and switching power unit 8 are mounted The micro computer 6 is connected to the temperature sensor 20 through a conductive path on the printed circuit board 3 The temperature sensor 20 is disposed inside the housing 2 of control unit 1 The drive power output section 4 is located under the printed circuit board 3 and brought into direct contact with a heat sink 5 at the bottom thereof The heat sink 5 serving as a water cooling type radiator receives cooling water forcibly circulated by a pump 12 through a hose 10 A water cooling unit 13 disposed in series and upstream of pump 12 is connected to pump 12 through hose 10 in order to cool down the circulated hot water before it is sucked up by pump 12 A unit disposed upstream of water cooling unit 13 is a heat generator 14 serving as a heat generating source other than control unit 1 Housing 2 and heat sink 5 are integrally united as a single package accommodating the control unit 1 The operating section 15 has a knob slidable in a right and left direction Users can manipulate this knob to adjust the output of compressor 11 Harness outgoing to compressor 11 or entering from battery 16 or operating section respectively passes through the wall of housing 2 and connected to the printed circuit board 3 althoug
15. e Tc is set lower than Ta by AT It means that the compressor 11 is continuously driven at the reduced 20 output W1 even the sensor temperature Ts falls below the upper limit temperature Ta unless it reaches the temperature Tc Steps S14 515 517 519 S22 S23 and 524 of FIG 7 Namely the difference AT Ta Tc is a hysteresis set for avoiding the hunting phenomenon in the convergence of sensor temperature Ts Once the sensor temperature Ts falls below the tempera ture Tc micro computer 6 restores the output command W to the target output WO so as to drive the compressor 11 in accordance with the user s request i e in direct proportion to the manipulation volume of the knob slidable on the operating section 15 Steps S19 and S20 of FIG 7 Then the flag F is reset to 0 i e F 0 Step S21 of FIG 7 thereby indicating that the output reduction control of compressor 11 in accordance with the present invention is terminated In this manner the present invention makes it possible to prevent the control unit from being damaged or malfunctioning and also to prevent an electrically driven compressor from being suddenly stopped except emergency conditions which require the shutdown of the compressor Other Embodiments FIGS 9A through 9C show schematic arrangements of a control system for an electrically driven compressor in accordance with a second embodiment of the present inven tion According to the second embodiment of the pre
16. edetermined critical value higher than said upper limit command generating means for generating an output command supplied to said compressor in such a manner that said output command is equalized to said target output when said temperature detected by said tem perature sensing means is within a predetermined allowable range while said output command is equal ized to said modified output when said temperature detected by said temperature sensing means is higher than said upper limit but lower than said critical value and drive means for actuating said compressor based on said output command generated from said command gen erating means 11 A control method for actuating an electrically driven compressor equipped in an automotive vehicle comprising the steps of reading a request signal representing a quantity of user s manual adjustment setting a target output of said compressor based on said request signal detecting a temperature of a component in the control apparatus judging whether said temperature is larger than a prede termined upper limit obtaining an output command in such a manner that said output command is equalized to said target output when said temperature is within a predetermined allowable range while said output command is reduced to a modified value larger than 0 when said temperature exceeds said upper limit and actuating said compressor based on said output command 12 A control method for act
17. equipped in an automotive vehicle character ized by manual switch means target output means tem perature sensing means modified output means command generating means and drive means According to the third aspect compressor control apparatus the manual switch means allows a use to adjust an output of the compressor and generates a request signal representing a quantity of user s manual adjustment The target output means receives the request signal from the manual switch means and obtains a target output of the compressor In this case the target output is proportional to the quantity of user s manual adjustment The temperature sensing means generates a temperature signal representing a temperature of a component in the control apparatus The modified output means receives the temperature signal from the temperature sensing means and obtains a modified output when the temperature detected by 5 651 260 3 the temperature sensing means exceeds a predetermined upper limit The modified output is set smaller than the target output obtained by the target output means but larger than 0 The command generating means generates an output command supplied to the compressor in such a manner that the output command is equalized to the target output when the temperature detected by the temperature sensing means is within a predetermined allowable range while the output command is equalized to the modified output when the temperature detected
18. exceeds the critical temperature Tb micro computer 6 immediately stops the compressor 11 i e W 0 regardless of the knob position of operating section 15 FIG 10 shows an arrangement of a control system for an electrically driven compressor in accordance with a third embodiment of the present invention The third embodiment is substantially identical with the first embodiment except that the temperature sensor 20 is directly attached on micro computer 6 The allowable upper limit temperature of micro computers is approximately 80 C i e Ta 80 C When the cooling ability is lowered the temperature of micro computer 6 possibly exceeds 80 C If the sensor temperature Ts exceeds 80 C micro computer 6 adjusts the power conversion in the drive power output section 4 i e reduces the output command W from WO to W1 until the sensor temperature Ts falls below within the allowable range less than 80 C FIG 11 shows an arrangement of a control system for an electrically driven compressor in accordance with a fourth embodiment of the present invention The fourth embodi ment is substantially identical with the first embodiment except that the temperature sensor 20 is directly attached on relay 7 The allowable upper limit of relays is approximately 80 C i e Ta 80 C For example if the heat generation in relay 7 is largely increased due to excessive current the temperature of relay 7 will exceed 80 C Upon sensor 20 detecting
19. ext in step S12 micro computer 6 makes a judgement as to whether the switch knob is in the OFF position If the judgement is YES step S12 this control routine is ceased at this moment On the other hand if the user sets the switch knob somewhere other than the OFF position i e NO in step 812 the control routine proceeds to step S13 wherein target output W0 of compressor 11 is determined based on the manipulation volume of the knob slidable on the operating section 15 The target output W0 is propor tional to the user s request Next in step S14 micro computer 6 reads sensor tem perature Ts detected by temperature sensor 20 Then it is judged in step 515 whether the sensor temperature Ts is larger than predetermined critical temperature Tb When the sensor temperature Ts exceeds the critical temperature Tb the control routine proceeds to step S16 to set the output command W to 0 W 0 and send this command to the compressor 11 thereby forcibly stopping the compressor 11 The critical temperature Tb is a fairly high temperature that possibly causes the fatal damage unavoidable without shut down of the electric compressor control system When the sensor temperature Ts is not larger than the critical temperature Tb the control routine proceeds to step 517 to check whether or not a flag F is 1 i e F 1 This flag F is used to indicate the fact that when F is 1 compressor 11 undergoes the output reduction control in
20. ger than the upper limit temperature Ta the control routine proceeds to step 58 to set the output command W to the target output 0 obtained in step S3 W W0 and send this command to the compressor 11 thereby driving the compressor 11 in direct proportion to the user s request In other words the tem perature Ta forms the reference or criterion point for judging whether the compressor 11 should be driven as requested by the user After completing step S8 the control routine returns to step S1 to repeat the above described processing On the other hand when the sensor temperature Ts is larger than the upper limit temperature Ta in step S7 micro computer 6 proceeds to step S9 to set a modified output W1 which is smaller than the target output WO by AW ie W1 W0 AW gt 0 Subsequently in step 510 micro computer 6 sets the output command W to the modified output W1 W W1 and sends this command to the compressor 11 thereby driving the compressor 11 at a slightly smaller output compared with the user s request In other words the sensor temperature Ts is higher than the allowable upper limit temperature Ta but less than the critical temperature Ta in this case therefore the micro computer 6 basically continues to drive compressor 11 although the output command W is set lower than the user s request After completing step S10 the control routine returns to step S4 to repeat the processing of step 54 and below FIG
21. h not shown in the drawings FIGS 2A through 2D show the correlations among vari ous factors such as temperature output power consumption and cooling ability in the electric compressor control system 5 651 260 7 illustrated in FIG 2 the electric power consumption increases with increasing output As illustrated in FIG 2 the heat generation inside the control unit 1 ie inner temperature is increased in proportion to the increase of the electric power consumption As illustrated in FIG 2C the inner temperature increases with increasing outer tempera ture temperature outside the control unit 1 Furthermore as illustrated in FIG 2D the inner temperature is reduced with increasing cooling ability It is now assumed that pump 12 is out of order and the water circulation amount is so reduced that the cooling ability is lowered from D to E In this case the inner temperature will exceed the predetermined upper limit if the compressor 11 is driven at the output J The inner tempera ture is detected by temperature sensor 20 and sent to micro computer 6 In response to the detection of such an excessive increase of inner temperature micro computer 6 adjusts the power conversion performed by the drive power output section 4 so as to reduce the output of compressor 11 to the level of output K where the inner temperature is equal to the predetermined upper limit According to the correlation shown in FIG
22. han 0 A seventh step is to generate an output command equalized to the modified output when the temperature exceeds the upper limit And an eighth step is to actuate the compressor based on the output command Still further a seventh aspect of the present invention provides a control method for actuating an electrically driven compressor equipped in an automotive vehicle char acterized by the following first to tenth steps A first step is to read a request signal representing a quantity of user s manual adjustment A second step is to set a target output of the compressor based on the request signal so that the target output is proportional to the quantity of user s manual adjustment A third step is to detect a tem perature of a component in the control apparatus A fourth step is to judge whether the temperature is larger than a predetermined critical value A fifth step is to stop the compressor when the temperature exceeds the critical value regardless of the quantity of user s manual adjustment A sixth step is to judge whether the temperature is larger than a predetermined upper limit In this case the upper limit is lower than the critical value A seventh step is to generate an output command equalized to the target output when the temperature is within a predetermined allowable range An eight step is to set a modified output by reducing the target output by a predetermined correction value The modified output is smalle
23. ing whether said temperature is larger than a prede termined critical value 10 15 20 16 stopping said compressor when said temperature exceeds said critical value regardless of said quantity of user s manual adjustment judging whether said temperature is larger than a prede termined upper limit said upper limit being lower than said critical value generating an output command equalized to said target output when said temperature is within a predetermined allowable range setting a modified output by reducing said target output by a predetermined correction value said modified output being smaller than said target output but larger than 0 generating an output command equalized to said modified output when said temperature is higher than said upper limit but lower than said critical value and actuating said compressor based on said output command 14 The compressor control method defined by claim 13 further comprising the steps of judging whether said temperature is larger than a prede termined reference value said reference value being lower than said upper limit and restoring said output command to said target output when said temperature falls below said reference value
24. larger than a predetermined upper limit 10 15 20 25 30 35 45 50 55 65 4 A fifth step is to obtain an output command in such a manner that the output command is equalized to the target output when the temperature is within a predetermined allowable range while the output command is reduced to a modified value larger than 0 when the temperature exceeds the upper limit And a sixth step is to actuate the compressor based on the output command Furthermore a sixth aspect of the present invention provides a control method for actuating an electrically driven compressor equipped in an automotive vehicle char acterized by the following first to eighth steps A first step is to read a request signal representing a quantity of user s manual adjustment A second step is to set a target output of the compressor based on the request signal In this case the target output is proportional to the quantity of user s manual adjustment A third step is to detect a temperature of a component in the control apparatus A fourth step is to judge whether the temperature is larger than a predetermined upper limit A fifth step is to generate an output command equalized to the target output when the temperature is within a predeter mined allowable range A sixth step is to set a modified output by reducing the target output by a predetermined correction value The modified output is smaller than the target output but larger t
25. lly driven compressor 11 connected to control unit 1 The switching power unit 8 converts the voltage of battery 16 into a voltage required in the drive power output section 4 The electrolytic capacitor 9 connected in parallel to switching power unit 8 absorbs current and voltage ripples when the drive power output section 4 converts the voltage of battery 16 into AC form The relay 7 opens or closes the power supplying circuit connecting battery 16 and drive power output section 4 The micro computer 6 controls the power conversion performed in the drive power output section 4 in response to the quantity of a user s manual adjustment entered through an operating section 15 The operating section 15 connected to the control unit 1 via a signal line such as harness is usually disposed on the instrument panel in a passenger compartment of an automotive vehicle The micro computer 6 further receives a detection signal from the temperature sensor 20 to adjust the power conver sion performed in the drive power output section 4 in response to the detected sensor temperature Thus the micro computer 6 drives a motor of compressor 11 in accordance with not only the user s request ie quantity of user s manual adjustment but also the detected sensor temperature In the driving operation of compressor 11 electric power is chiefly consumed in the drive power output section 4 FIG 1 shows a schematic arrangement of the control system for an ele
26. nt of a control system for an electrically driven compressor in accordance with a fourth embodiment of the present invention FIG 12 is an arrangement of a control system for an electrically driven compressor in accordance with a fifth embodiment of the present invention FIG 13 is an arrangement of a control system for an electrically driven compressor in accordance with a sixth embodiment of the present invention and FIG 14 is an arrangement of a control system for an electrically driven compressor in accordance with a seventh embodiment of the present invention DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be explained in greater detail hereinafter with reference to the accompanying drawings Identical parts are denoted by identical reference numerals throughout the views FIG 3 shows a circuit arrangement of the control system of an electrically driven compressor in accordance with the present invention 20 30 35 40 45 50 55 65 6 A control unit 1 connected to a battery 16 receives DC direct current power from battery 16 The control unit 1 comprises a drive power output section 4 a micro computer 6 a relay 7 a switching power unit 8 an electrolytic capacitor 9 and a temperature sensor 20 The drive power output section 4 converts the supplied DC power into AC alternating current form and supplies thus converted AC power to an electrica
27. o whether the switch knob is in an OFF position If the judgement is YES in step S2 this control routine is ceased at this moment On the other hand if the user sets the switch knob somewhere other than the OFF position i e NO in step S2 the control routine proceeds to step S3 wherein a target output WO of compressor 11 is determined based on the manipulation volume of the knob slidable on the oper ating section 15 The target output WO is proportional to the user s request Next in step S4 micro computer 6 reads a sensor tem perature Ts detected by temperature sensor 20 Then lit is judged in step 55 whether the sensor temperature Ts is larger than a predetermined critical temperature Tb When the sensor temperature Ts exceeds the critical temperature Tb the control routine proceeds to step S6 to set the output command W to 0 W 0 and send this command to the compressor thereby forcibly stopping the compressor 11 10 15 20 30 35 45 50 55 65 8 The critical temperature Tb is a fairly high temperature that possibly causes the fatal damage unavoidable without shut down of the electric compressor control system When the sensor temperature Ts is not larger than the critical temperature Tb the control routine proceeds to step S7 to further make a judgement as to whether the sensor temperature Ts is larger than a predetermined upper limit temperature Ta When the sensor temperature Ts is not lar
28. perature Ts is higher than the allowable upper limit temperature Ta but less than the critical temperature Ta in this case therefore the micro computer 6 basically continues to drive compressor 11 although the output command W is set lower than the user s request After completing step S23 flag F is set to 1 i e F 1 to indicate that compressor 11 undergoes the output reduction control in accordance with the present invention Then the control routine returns to step S14 to repeat the processing of step S14 and below FIG 8 is a time chart showing a change of compressor output in relation to a detected temperature in accordance with the present invention As shown in FIG 8 the output command W of the compressor 11 is reduced from W0 to W1 when the sensor temperature Ts exceeds the allowable upper limit tempera ture Ta The micro computer 6 maintains the output com mand W at the reduced value W1 for a while unless the sensor temperature Ts exceeds the critical temperature Tb In the event the sensor temperature Ts accidentally reaches the critical temperature Tb micro computer 6 immediately changes the output command W to 0 so as to forcibly stop the compressor 11 Steps S15 and S16 of FIG 7 On the other hand when the increase of sensor tempera ture Ts is relatively moderate micro computer 6 continues to drive compressor 11 at the reduced output W1 until the sensor temperature Ts falls below the temperature Tc The temperatur
29. r 20 is directly attached on elec trolytic capacitor 9 The allowable upper limit of electrolytic capacitors is approximately 80 C i e Ta 80 When the cooling ability is lowered due to for example disorder of pump 12 the temperature of electrolytic capaci tor 9 possibly exceeds 80 C Upon sensor 20 detecting this excessive increase of temperature micro computer 6 adjusts the power conversion in the drive power output section 4 i e reduces the output command W from W0 to W1 until the sensor temperature Ts falls below within the allowable range less than 80 C In general the life of electrolytic capacitors is doubled by reducing the temperature by an amount of 10 C Hence the electrolytic capacitor 9 when it has a life of 5 000 hours at 859 C can extend its life to 10 000 hours by setting the allowable upper limit temperature Ta at 75 C in this embodiment FIG 14 is an arrangement of a control system for an electrically driven compressor in accordance with a seventh embodiment of the present invention The seventh embodi ment is substantially identical with the first embodiment except that an alarm indicator 21 is provided on the oper ating section 15 According to the seventh embodiment micro computer 6 sends an alarm signal to operating section 15 as soon as the sensor temperature Ts exceeds the upper limit temperature Ta Upon receiving the alarm signal the alarm indicator 21 is turned on to inform passenge
30. r than the target output but larger than 0 A ninth step is to generate an output command equalized to the modified output when the temperature is higher than the upper limit but lower than the critical value And a tenth step is to actuate the compressor based on the output command According to features of the preferred embodiment it is desirable to provide the following steps an eleventh step is to judge whether the temperature is larger than a Predetermined reference value The reference value is set lower than the upper limit And a twelfth step is to restore the output command to the target output when the temperature falls below the reference value Thus according to the present invention it becomes possible to promptly and adequately suppress the output of 5 651 260 5 the compressor in response to a detected increase of the inside or peripheral temperature of the control system thereby stabilizing the operation of the compressor and assuring reliability of the air conditioning system for an automotive vehicle BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects features and advantages of the present invention will become more apparent from the following detailed description which is to be read in con junction with the accompanying drawings in which FIG 1 is a view showing a schematic arrangement of a control system for an electrically driven compressor in accordance with a first embodiment of the present
31. rature sensing means and forcibly stops the compressor when the temperature detected by the tempera ture sensing means exceeds a predetermined critical value higher than the upper limit The command generating means generates an output command supplied to the compressor in such a manner that the output command is equalized to the target output when the temperature detected by the temperature sensing means is within a predetermined allowable range while the output command is equalized to the modified output when the temperature detected by the temperature sensing means is higher than the upper limit but lower than the critical value And the drive means actuates the compressor based on the output command generated from the command generat ing means Moreover the present invention provides the method for actuating the electrically driven compressor of an air con ditioning system installed in an automotive vehicle More specifically a fifth aspect of the present invention provides a control method for actuating an electrically driven compressor equipped in an automotive vehicle com prising the following first to sixth steps A first step is to read a request signal representing a quantity of user s manual adjustment A second step is to set a target output of the compressor based on the request signal A third step is to detect a temperature of a component in the control apparatus A fourth step is to judge whether the temperature is
32. rature sensor detects a temperature of a relay provided in said control apparatus 5 651 260 13 5 compressor control apparatus defined by claim 1 wherein said temperature sensor detects a temperature of a power unit provided in said control apparatus 6 The compressor control apparatus defined by claim 1 wherein said temperature sensor detects a temperature of an electrolytic capacitor provided in said control apparatus 7 The compressor control apparatus defined by claim 1 further comprising an alarm indicator generating an alarm whenever the temperature detected by said temperature sensor goes out of a predetermined allowable range 8 A control apparatus for actuating an electrically driven compressor equipped in an automotive vehicle comprising manual switch means for allowing a use to adjust an output of said compressor and generating a request signal representing a quantity of user s manual adjust ment command generating means for receiving said request signal and generating an output command supplied to said compressor in accordance with said quantity of manual adjustment drive means for actuating said compressor based on said output command temperature sensing means for generating a temperature signal representing a temperature of a component in the control apparatus and adjusting means for receiving said temperature signal from said temperature sensing means and generating a modified output command
33. rs in a compartment room of an automotive vehicle of the output reduction operation of the compressor This invention may be embodied in several forms without departing from the spirit of essential characteristics thereof the present embodiments as described are therefore intended to be only illustrative and not restrictive since the scope of the invention is defined by the appended claims rather than by the description preceding them and all changes that fall within metes and bounds of the claims or equivalents of such metes and bounds are therefore intended to be embraced by the claims What is claimed is 1 A control apparatus for actuating an electrically driven compressor equipped in an automotive vehicle comprising a temperature sensor generating a signal representing a temperature of a component in the control apparatus and control means connected to said temperature sensor for adjusting an output command supplied to said electri cally driven compressor in accordance with said signal generated from said temperature sensor 2 The compressor control apparatus defined by claim 1 wherein said temperature sensor detects a temperature of a heat radiator provided in said control apparatus 3 The compressor control apparatus defined by claim 1 wherein said temperature sensor detects a temperature of a micro computer provided in said control apparatus 4 The compressor control apparatus defined by claim 1 wherein said tempe
34. sent 5 651 260 1 invention the temperature sensor 20 is attached on the heat sink 5 to directly detect the temperature of heat sink 5 In an embodiment shown in FIG 9 heat sink 5 is cooled down by an air cooling unit 17 with an axial fiow fan In an embodiment shown in FIG 9B heat sink 5 is cooled by water in the same manner as the first embodiment Accord ing to an embodiment shown in FIG 9 heat sink 5 is cooled down heat sink package 18 where electric compressor control unit 1 is directly mounted on the heat sink package 18 by means of screws 19 The heat sink package 18 is a water cooling type which mounts the heat generator 14 together with control unit 1 If the axial flow fan equipped air cooling unit 17 or the water cooling unit 13 is out of order or the connection between the control unit 1 and the heat sink package 18 is not sufficiently tight for example due to looseness of screws 19 the cooling ability will be fairly lowered accom panied by an increase of temperature of heat sink 5 which may exceeds the allowable upper limit Ta Receiving the temperature of heat sink 5 from temperature sensor 20 micro computer 6 adjusts the power conversion in the drive power output section 4 i e reduces the output command W from to W1 when the sensor temperature Ts exceeds the upper limit temperature Ta until the sensor temperature Ts falls below within the allowable range If the temperature of heat sink 5
35. sumption Furthermore in the event of unusual increase of temperature some of electrically driven compressor can be automatically stopped to prevent any damage from occur ring by such excessive heat generations According to the above described conventional systems when the temperature of the control system is extraordinar increased the only effective countermeasure is to stop the electric compressor otherwise the control system of the electric compressor will be fatally damaged However in view of the driving safety sudden stop or malfunction of an air conditioning system in an automotive vehicle is not desirable and recommendable For example sudden stop of the air conditioning system will make it impossible to keep a clean view through the front windshield glass since the glass will be clouded up with moisture Furthermore a drive or passenger may be surprised or frightened by the sudden stop of blow air Needless to say such sudden stop or malfunction will make passengers feel uncomfortable Still further it is essentially important to assure a long life of the control system of each electric compressor In this respect an electrolytic capacitor which essentially deter mines the life of the electric compressor control system since its life is significantly short needs to be kept safely so as not to suffer from increase of temperature SUMMARY OF THE INVENTION In view of the above described problems encountered in
36. this excessive increase of temperature micro computer 6 adjusts the power conversion in the drive power output section 4 i e reduces the output command W from WO to W1 until the sensor temperature Ts falls below within the allowable range less than 80 C FIG 12 shows an arrangement of a control system for an electrically driven compressor in accordance with a fifth embodiment of the present invention The fifth embodiment is substantially identical with the first embodiment except that the temperature sensor 20 is directly attached on switch ing power unit 8 The allowable upper limit of switching power units is approximately 80 C i e Ta 80 C When the heat generation in the switching power unit 8 is largely increased due to for example an excessive increase 10 15 25 30 35 45 50 55 65 12 of switching loss the temperature of switching unit 8 possibly exceeds 80 C Upon sensor 20 detecting this excessive increase of temperature micro computer 6 adjusts the power conversion in the drive power output section 4 i e reduces the output command W from 0 to W1 until the sensor temperature Ts falls below within the allowable range less than 80 C FIG 13 shows an arrangement of a control system for an electrically driven compressor in accordance with a sixth embodiment of the present invention The sixth embodiment is substantially identical with the first embodiment except that the temperature senso
37. uating an electrically driven compressor equipped in an automotive vehicle comprising the steps of reading a request signal representing a quantity of user s manual adjustment setting a target output of said compressor based on said request signal said target output being proportional to said quantity of user s manual adjustment detecting a temperature of a component in the control apparatus 10 15 20 30 35 40 45 50 5 651 260 15 judging whether said temperature is larger than a prede termined upper limit generating an output command equalized to said target output when said temperature is within a predetermined allowable range setting a modified output by reducing said target output by predetermined correction value said modified output being smaller than said target output but larger than 0 generating an output command equalized to said modified output when said temperature exceeds said upper limit and actuating said compressor based on said output command 13 A control method for actuating an electrically driven compressor equipped in an automotive vehicle comprising the steps of reading a request signal representing a quantity of user s manual adjustment setting a target output of said compressor based on said request signal said target output being proportional to said quantity of user s manual adjustment detecting a temperature of a component in the control apparatus judg
38. ut command is equal ized to said modified output when said temperature detected by said temperature sensing means exceeds said upper limit and drive means for actuating said compressor based on said output command generated from said command gen erating means 10 A control apparatus for actuating an electrically driven compressor equipped in an automotive vehicle comprising 14 manual switch means for allowing a use to adjust an output of said compressor and generating a request signal representing a quantity of user s manual adjust ment 5 target output means for receiving said request signal from said manual switch means and obtaining a target output of said compressor said target output being propor tional to said quantity of user s manual adjustment temperature sensing means for generating a temperature signal representing a temperature of a component in the control apparatus modified output means for receiving said temperature signal from said temperature sensing means and obtain ing a modified output when said temperature detected by said temperature sensing means exceeds a predeter mined upper limit said modified output being smaller than said target output obtained by said target output means but larger than 0 emergency means for receiving said temperature signal from said temperature sensing means and forcibly Stopping said compressor when said temperature detected by said temperature sensing means exceeds a pr
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