Source: http://www.google.com/patents/USRE42006?ie=ISO-8859-1&dq=5359317
Timestamp: 2015-04-25 01:40:21
Document Index: 285496358

Matched Legal Cases: ['Application No. 04', 'Application No. 05016504', 'Application No. 05016505', 'Application No. 200610128576', 'Application No. 200610128576', 'Application No. 200610128576', 'Application No. 200410085953']

Patent USRE42006 - Adaptive control for a refrigeration system using pulse width modulated duty ... - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsA diagnostic system includes a controller adapted for coupling to a compressor or electronic stepper regulator valve. The controller produces a variable duty cycle control signal to adjust the capacity of the compressor or valve position of the electronic stepper regulator valve as a function of demand...http://www.google.com/patents/USRE42006?utm_source=gb-gplus-sharePatent USRE42006 - Adaptive control for a refrigeration system using pulse width modulated duty cycle scroll compressorAdvanced Patent SearchPublication numberUSRE42006 E1Publication typeGrantApplication numberUS 10/760,173Publication dateDec 28, 2010Filing dateJan 16, 2004Priority dateJun 7, 1995Fee statusPaidAlso published asCN1238674C, CN1272171A, CN1308633C, CN1607478A, CN1607478B, CN1664372A, CN1664373A, CN1664473A, CN1664474A, CN1664475A, CN1664476A, CN1920305A, CN1952813A, CN1952813B, CN100344923C, CN100432584C, CN100432585C, CN100513791C, CN100565050C, DE69833266D1, DE69833266T2, EP1025403A1, EP1025403A4, EP1025403B1, EP1489368A2, EP1489368A3, EP1489368B1, EP1598611A2, EP1598611A3, EP1598612A2, EP1598612A3, EP1598613A2, EP1598613A3, EP1598614A2, EP1598615A2, EP1598615A3, US6047557, US6393852, US6408635, US6438974, US6449972, US6467280, US6499305, US6662578, US6662583, US6679072, US7389649, US7419365, US7654098, US20010002239, US20010045097, US20010049942, US20020178737, US20030084672, US20030089119, US20030094004, US20040123612, US20060288715, US20070022771, WO1999017066A1Publication number10760173, 760173, US RE42006 E1, US RE42006E1, US-E1-RE42006, USRE42006 E1, USRE42006E1InventorsHung M. Pham, Abtar Singh, Jean-Luc Caillat, Mark BassOriginal AssigneeEmerson Climate Technologies, Inc.Export CitationBiBTeX, EndNote, RefManPatent Citations (74), Non-Patent Citations (10), Referenced by (1), Classifications (71), Legal Events (2) External Links: USPTO, USPTO Assignment, EspacenetAdaptive control for a refrigeration system using pulse width modulated duty cycle scroll compressor
US RE42006 E1Abstract
1. A diagnostic system for an electronic stepper regulator valve, comprising:
a controller adapted for coupling to an electronic stepper regulator valve, said controller producing a variable duty cycle control signal for adjusting a valve position of said electronic stepper regulator valve, in which said duty cycle is a function of demand for cooling; a diagnostic module coupled to said controller for monitoring and comparing said duty cycle with at least one predetermined fault value indicative of a fault condition; and an alert module responsive to said diagnostic module for issuing an alert signal when said duty cycle bears a predetermined relationship to said fault value. 2. The diagnostic A control system of claim 1, wherein said diagnostic module monitors and compares at least one of the following conditions comprising:
a controller operable to produce a variable duty cycle control signal for controlling a cooling system device in which said duty cycle is a function of demand for cooling; and a diagnostic module associated with said controller and operable to compare said duty cycle with a predetermined value indicative of a system condition and issue a signal when said duty cycle bears a predetermined relationship to a fault value; wherein said diagnostic module monitors at least one of the following conditions:saida valve position of saidan electronic stepper regulator; an error value percentage indicative of the percentage of sampled error within an accepted offset range for a defined period of time; a moving average of said valve position for a defined period of time; a steady state loading percentage set equal to said moving average of said valve position for a defined period of time when said error value percentage is less than fifty percent; a discharge cooling fluid temperature; an evaporator coil inlet temperature; an evaporator coil exit temperature; a moving average of a difference between said discharge cooling fluid temperature and said evaporator coil inlet temperature; a moving average of a difference between said evaporator coil exit temperature and said evaporator coil inlet temperature to approximate a superheat value; and a length of time said evaporator coil exit temperature is less than said evaporator coil inlet temperature during a predefined period of time. 3. The diagnostic control system of claim 1 15, wherein said diagnostic module monitors a percentage of sampled error over a defined period of time.
4. The diagnostic control system of claim 3, wherein said predetermined fault value is an accepted offset range.
5. The diagnostic control system of claim 4, wherein said diagnostic module determines an error value percentage indicative of said percentage of sampled error within said accepted offset range for said defined period of time.
6. The diagnostic system of claim 5, wherein said diagnostic module determines an error value percentage indicative of said percentage of sampled error within said accepted offset range for said defined period of time.
7. The diagnostic control system of claim 6 27, wherein said alert module issues an alert signal when said a valve position of said electronic stepper regulator valve is approximately zero percent for approximately ninety percent of said defined period of time and said error value percentage is less than one hundred percent, said alert signal indicating said electronic stepper regulator valve is over-sized.
8. The diagnostic control system of claim 6 27, wherein said diagnostic module further monitors and compares a superheat value indicative of evaporator superheat.
9. The diagnostic control system of claim 8, wherein said alert module issues an alert signal when said valve position of said electronic stepper regulator valve is approximately one hundred percent for approximately ninety percent of said defined period of time, said error value percentage is approximately zero percent, and said superheat value is approximately greater than 5� F., said alert signal indicating said electronic stepper regulator valve is undersized.
10. The diagnostic control system of claim 8, wherein said diagnostic module further monitors and compares an evaporator coil inlet temperature value indicative of evaporator coil inlet temperature.
11. The diagnostic control system of claim 10, wherein said alert module issues an alert signal when said error value percentage is approximately zero percent, said valve position of said electronic stepper regulator valve is approximately zero percent for approximately one hundred percent of said defined period of time, said evaporator coil inlet temperature value is less than approximately 32� F., and said superheat value is approximately greater than 5� F., said alert signal indicating said electronic stepper regulator valve is stuck open.
12. The diagnostic control system of claim 10, wherein said error value percentage is approximately zero percent, said valve position of said electronic stepper regulator valve is approximately one hundred percent for approximately one hundred percent of said defined period of time, said evaporator coil inlet temperature value is approximately greater than 32� F., and said superheat value is approximately greater than 5� F., said alert signal indicating said electronic stepper regulator valve is stuck closed.
13. The diagnostic control system of claim 10, wherein said diagnostic module further monitors and compares an evaporator coil exit temperature value indicative of evaporator coil exit temperature.
14. The diagnostic control system of claim 13, wherein said alert module issues an alert signal when said valve position of said electronic stepper regulator valve is approximately one hundred percent for approximately one hundred percent of said defined period of time, said error value percentage is approximately zero, said superheat value is approximately less than 5� F., said evaporator coil inlet temperature value is approximately less than 25� F., and said evaporator coil exit temperature value is less than said evaporator coil inlet temperature value for greater than fifty percent of said defined period of time, said alert signal indicating that air flow to an evaporator is blocked or evaporator fans are not operating properly.
15. The control system of claim 2, wherein said cooling system device is selected from a group comprising: an expansion device, a fan, a compressor, and a refrigerant control device.
16. The control system of claim 15, wherein said expansion device is at least one of an orifice, thermal expansion valve, and electronic expansion valve.
17. The control system of claim 15, wherein said refrigerant control device is an evaporator stepper regulator.
18. The control system of claim 15, wherein said fan is a variable speed fan.
19. The control system of claim 15, wherein said fan is a condenser fan.
20. The control system of claim 19, wherein said condenser fan is a variable speed fan.
21. The control system of claim 2, wherein said module includes said diagnostic module and an alert module.
22. The control system of claim 21, wherein said alert module issues said signal.
23. The control system of claim 2, wherein said signal is an alert signal.
a controller operable to produce a variable duty cycle control signal for controlling an electronic stepper regulator valve in which said duty cycle is a function of demand for cooling; and a module associated with said controller and operable to compare said duty cycle with a predetermined value indicative of a system condition and issue a signal when said duty cycle bears a predetermined relationship to said fault value. 25. The control system of claim 5, wherein said module includes a diagnostic module and an alert module, said diagnostic module comparing said duty cycle with said predetermined value, and said alert module issuing said signal, said predetermined value being said fault value and said signal being an alert signal.
26. The control system of claim 24, wherein said module includes a diagnostic module and an alert module.
27. The control system of claim 26, wherein said diagnostic module compares said duty cycle with said predetermined value.
28. The control system of claim 26, wherein said alert module issues said signal.
29. The control system of claim 24, wherein said signal is an alert signal.
30. The control system of claim 24, further comprising an expansion device controlled by said variable duty cycle.
31. The control system of claim 24, further comprising a fan controlled by said variable duty cycle.
32. The control system of claim 24, wherein said controller is operable to control a fan based on said duty cycle.
33. The control system of claim 32, further comprising an expansion device controlled by said variable duty cycle.
34. The control system of claim 32, wherein said fan is a variable speed fan.
35. The control system of claim 34, wherein said fan is a condenser fan.
36. The control system of claim 24, wherein said controller is operable to control a compressor based on said duty cycle.
37. The control system of claim 36, further comprising an expansion device controlled by said variable duty cycle.
38. The control system of claim 36, further comprising a variable speed fan controlled by said controller.
39. The control system of claim 38, wherein said controller controls said fan based on a current operating duty cycle of said compressor.
This is a division of U.S. Ser. No. 09/886,592, filed Jun. 21, 2001, entitled �Adaptive Control For A Refrigeration System Using Pulse Width Modulated Duty Cycle Scroll Compressor;� which is a division of U.S. Ser. No. 09/524,364, filed Mar. 14, 2000 U.S. Pat. No. 6,408,635; which is a division of U.S. Ser. No. 08/939,779, filed Sep. 29, 1997, now U.S. Pat. No. 6,047,557; which is a continuation-in-part of U.S. Ser. No. 08/486,118, filed Jun. 7, 1995, now U.S. Pat. No. 5,741,120, each of which is incorporated herein by reference.
The present invention relates generally to refrigeration systems, compressor control systems and refrigerant regulating valve control systems. More particularly, the invention relates to a refrigeration system employing a pulse width modulated compressor or evaporator stepper regulator controlled by a variable duty cycle signal derived from a load sensor. Preferably an adaptive controller generates the variable duty cycle signal. The compressor has two mechanical elements separated by a seal, and these mechanical elements are cyclically movable relative to one another to develop fluid pressure. The compressor includes a mechanism to selectively break the seal in response to the control signal, (hereby modulating the capacity of the system.
Periodic defrosting also introduces thermal fluctuations into the system. Unlike thermal fluctuations due to environmental conditions, the thermal fluctuations induced by the defrost cycle are caused by the control system itself and not by the surrounding environment.
FIG. 12 is a waveform diagram illustrating the variable duty cycle signal produced by (be controller and illustrating the operation at a constant frequency;
The refrigeration system of the invention employs a compressor controller 52 that supplies a pulse width modulated control signal on line 54 to a solenoid valve 56 on compressor 30. The compressor controller adjusts the pulse width of the control signal using an algorithm described 1 below. A suitable load sensor such as temperature sensor 58 supplies the input signal used by the controller to determine pulse width.
The exemplary compressor 30 includes an outer shell 61 and an orbiting scroll member 64 supported on upper bearing housing 63 and drivingly connected to crankshaft 62 via crank pin 65 and drive bushing 60. A second non-orbiting scroll member 67 is positioned in meshing engagement with scroll member 64 and axially movably secured to upper bearing housing 63. A partition plate 69 is provided adjacent the upper end of shell 61 and serves to define a discharge chamber 70 at the upper end thereof.
Referring to FIG. 5, a single compressor 30 and condenser 32 can service several distributed refrigeration cases or several distributed cooling units in a heating and cooling (HVAC) system. In FIG. 5 the refrigeration cases or cooling system housings are shown as dashed boxes, designated 34a, 34b, and 34c. Conveniently, the compressor 30 and condenser 32 may be disposed within or attached to one of the refrigeration cases or housings, such as refrigeration case or housing 34a.
As an alternate control technique, one or more of the suction lines exiting the evaporator can be equipped with an electrically controlled valve, such as an evaporator pressure regulator valve 45c. Valve 45c is coupled to controller 52, as illustrated. It may be supplied with a suitable control signal, depending on the type of the valve. A stepper motor valve may be used for this purpose, in which case controller 30 would supply a suitable signal to increment or decrement the setting of the stepper motor to thereby adjust the orifice size of the valve. Alternatively, a pulse width modulated valve could be used, in which case it may be controlled with the same variable duty cycle signal as supplied to the compressor 30.
T/F Type
The preferred compressor controller in one form is auto-configurable. The controller includes an optional adaptive tuning module 120 that automatically adjusts the control algorithm parameters (the proportional constant K) based on operating conditions of the system. The adaptive tuning module senses the percent loading (on lead 104) and the operating state (on lead 108) as well as the measured temperature after signal conditioning (on lead 122). Module 120 supplies the adaptive tuning parameters to control block 102, as illustrated. The current embodiment supplies proportional constant K on lead 124 and SSL parameter on lead 126, indicative of steady-state loading percent. A system alarm signal on lead 126 alerts the control block module when the system is not responding as expected to changes in the adaptively tuned parameters. The alarm thus signals when there may be a system malfunction or loss of refrigerant charge. The alarm can trigger more sophisticated diagnostic routines, if desired. The compressor controller provides a number of user interface points through which user-supplied settings are input. The defrost type (internal/external) input 116 and the internal defrost parameters on input 118 have already been discussed. A user input 128 allows the user to specify the temperature set point to the adaptive tuning module 120. The same information is supplied on user input 130 to the control block module 102. The user can also interact directly with the control block module in a number of ways. User input 132 allows the user to switch the compressor on or off during defrost mode. User input 134 allows the user to specify the initial controller parameters, including the initial proportional constant K. The proportional constant K may thereafter be modified by the adaptive tuning module 120. User input 136 allows the user to specify the pressure differential (dP) that the system uses as a set point.
The decision logic module 166 (FIG. 9) determines the duty cycle of the variable duty cycle signal. This is output on lead 182, designated % Loading. The decision logic module also generates the compressor ON/OFF signal on lead 184. The actual decision logic will be described below in connection with FIG. 11. The decision logic module is a form of proportional integral (PI) control that is based on an adaptively calculated cycle time Tcyc. This cycle time is calculated by the calculation module 186 based on a calculated error value generated by module 188. Referring back to FIG. 6, the conditioned pressure differential signal on lead 122 (Cond dP) is supplied to the Calculate Error module 188 (FIG. 9) along with the pressure differential set point value as supplied through user input 136 (FIG. 6). The difference between actual and set point pressure differentials is calculated by module 188 and fed to the calculation module 186. The adaptive cycle time Tcyc is a function of the pressure differential error and the operating state as determined by the find operating state module 164 according to the following calculation:
Tcyc(new)=Tcyc(old)+Kc*Error (1)
Kc: proportional constant; and Error: (actual-set point) suction pressure swing. The presently preferred PI control algorithm implemented by the decision logic module 166 is illustrated in FIG. 11. The routine begins at step 200 by reading the user supplied parameters K, Ti, Tc and St. See FIG. 6 for a description of these user supplied values. The constant Kp is calculated as being equal to the initially supplied value K; and the constant Ki is calculated as the product of the initially supplied constant K and the ratio Tc/Ti. Next, at step 202 a decision is made whether the absolute value of the error between set point temperature and conditioned temperature (on lead 190, FIG. 9) is greater than 5� F. If so, the constant Kp is set equal to zero in step 204. If not, the routine simply proceeds to step 206 where a new loading percent value is calculated as described by the equation in step 206 of FIG. 11. If the load percent is greater than 100 (step 208), then the load percent is set equal to 100% at step 210. If the load percent is not greater than 100% but is less than 0% (step 212) the load percent is set equal to 0% at step 214. If the load percent is between the 0% and 100% limits, the load percent is set equal to the new load percent at step 216.
The controller of the invention operates at a rate that is at least four times faster (typically on (be order of at least eight times faster) than the thermal time constant of the load. In the presently preferred embodiment the cycle time of the variable duty cycle signal is about eight times shorter than the time constant of the load. By way of non-limiting example, the cycle time of the variable duty cycle signal might be on the order of 10 to 15 seconds, whereas the time constant of the system being cooled might be on the order of 1 to 3 minutes. The thermal time constant of a system being cooled is generally dictated by physical or thermodynamic properties of the system. Although various models can be used to describe the physical or thermodynamic response of a heating or cooling system, the following analysis will demonstrate the principle.
ΔT=ΔTss[1−exp(−t/γ)]+ΔT0exp(=τ/γ).
ΔT=air temperature change across coil ΔTss=steady state air temperature change across coil ΔT0=air temperature change across the coil at time zero t=time γ=time constant of coil.
∃=�[(1−e1/γ1)+(1−e1/γ2)]
∃=temperature change across coil/steady state temperature change across coil t=time γ1=time constant based on mass of coil γ2=time constant based on time required to remove excess refrigerant from evaporator In practice, the controller of the invention cycles at a rate significantly faster than conventional controllers. This is because the conventional controller cycles on and off in direct response to the comparison of actual and set-point temperatures (or pressures). In other words, the conventional controller cycles on when there is demand for cooling, and cycles off when the error between actual and set-point temperature is below a predetermined limit. Thus the on-off cycle of the conventional controller is very highly dependent on the time constant of the system being cooled.
Thus, one important advantage of the adaptive controller is its ability to perform adaptive tuning. In general, tuning involves selecting the appropriate control parameters so that the closed loop system is stable over a wide range of operating conditions, responds quickly to reduce the effect of disturbance on the control loop and docs not cause excessive wear of mechanical components through continuous cycling. These are often mutually exclusive criteria, and a compromise must generally be made. In FIG. 18 (and also FIG. 6) there are two basic control loops: the refrigeration control loop and the adaptive tuning loop. The refrigeration control loop is administered by control block module 102; the adaptive loop is administered by adaptive tuning module 120. Details of the adaptive tuning module 120 are shown in FIGS. 15, 16a-16c and 17. The presently preferred adaptive tuning module uses a fuzzy logic control algorithm that will be described in connection with FIGS. 18-20.
The block diagram of the adaptive scheme is shown in FIG. 18. There are two basic loops�The first one is the PID control loop 260 that runs every �dt� second and the second is the adaptive loop 262 that runs every �ta� second. When the control system starts, the PID control loop 260 uses a default value of gain (K) to calculate the control output. The adaptive loop 262, checks the error e(t) 264 every �ta� seconds 266 (preferably less than 0.2 * dt seconds). At module 268 if the absolute value of error, e(t), is less than desired offset (OS), a counter Er_new is incremented. The Offset (OS) is the acceptable steady-state error (e.g. for temperature control it may be +/1� F.). This checking process continues for �tsum� seconds 270 (preferably 200 to 500 times dt seconds). After �tsum� seconds 270, the value Er_new is converted into percentage (Er_new% 272). The parameter Er_new% 272 indicates the percentage of sampled e(t) that was within accepted offset (OS) for �tsum� time. In other words, it is a measure of how well the control variable was controlled for past �tsum� seconds. A value of 100% means �light� control and 0% means �poor� control. Whenever Er_new% is 100%, the gain remains substantially unchanged as it indicates lighter control. However, if Er_new happens to be between 0 and 100%, adaptive fuzzy-logic algorithm module 274 calculates a new gain (K_new 276) that is used for next �tsum� seconds by the control algorithm module 278.
In the preferred embodiment, there is one output and two inputs to the fuzzy-logic algorithm module 274. The output is the new gain (K_new) calculated using the input, Er_new%, and a variable, Dir, defined as follows:
Dir=Sign[(Er_new%−ER_old%)*(K_new−K_old)] (2)
Sign stands for the sign (+ve, −ve or zero) of the term inside the bracket; Er_new% is the percentage of e(t) that is within the offset for past �tsum� seconds; Er_old% is the value of Er_new% in �(tsum−1)� iteration; K_new is the gain used in �tsum� time; and K_old is the gain in (tsum−1) time. For example, suppose the controller starts at 0 seconds with a default value of K=10 and, ta=1 seconds, tsum=1000 seconds and OS=1. Suppose 600 e(t) data out of a possible 1000 data was within the offset. Therefore, after 1000 sec. Er_new%=60 (i.e., 600/1000*100), K_new=10. Er_old% and K_old is set to zero when the adaptive fuzzy-logic algorithm module 274 is used the first time. Plugging these numbers in Eq.(2) gives the sign of the variable �Dir� as positive. Accordingly, the inputs to the adaptive fuzzy-logic module 274 for the first iteration are respectively, Er_new%=60 and Dir=+ve.
A membership function is a mapping between the universe of discourse (x-axis) and the grade space (y-axis). The universe of discourse is the range of possible values for the inputs or outputs. For ER_new% it is preferably from 0 to 100. The value in the grade space typically ranges from 0 to 1 and is called a fuzzy input, truth value, or a degree of membership. FIG. 19 shows graph 300 which contains the membership functions for the input, Er_new%. Er_new% is divided into three linguistic variables�LARGE (304), MEDIUM (306) AND SMALL (308). For Er_new%=60, the fuzzy inputs (or degree of membership function) are −0.25 of LARGE and 0.75 of MEDIUM. The input variable �Dir� is well defined (+ve, −ve or zero) and thus does not require a membership function in this application. The next step is to create the �Truth Table� or Rule Evaluation.
Rule evaluation takes the fuzzy inputs from the fuzzification step and the rules from the knowledge base and calculates fuzzy outputs. FIG. 20 shows the rules as truth table. For the first column and first row, the rule is: �IF ER_new% is LARGE AND Dir is NEGATIVE THEN New Gain is NO CHANGE (NC)� (i.e. if the percentage of e(t) data that is within the offset (OS) for last �tsum� seconds is LARGE and the direction (DIR) is NEGATIVE/ZERO then do not change the existing K value (NO CHANGE)).
In the example, because ER_new% has fuzzy inputs LARGE (0.25) AND MEDIUM (0.75) with POSITIVE Dir, the rules that will be used are:
IF ER_new% is LARGE (0.25) AND Dir is POSITIVE THEN New Gain is NO CHANGE (NC=1)
IF ER_new% is MEDIUM (0.75) AND Dir is POSITIVE THEN New Gain is POSITIVE SMALL CHANGE (PSC=1.2)
Finally, the defuzzification process converts the fuzzy outputs from the rule evaluation step into the final output by using Graph 310 of FIG. 21. Graph 310, uses the following labels =�NBC� for negative big change; �NSC� for negative small change; �NC� for no change; �PSC� for positive small change; and PBC for positive big change. The Center of Gravity or centroid method is used in the preferred embodiment for defuzzification. The output membership function for change in gain is shown in FIG. 21.
The centroid (the Fuzzy-Logic Output) is calculated as: Centroid = K - new � [ ∑ μ ( x ) � x allx Σ μ ( x ) allx ] where:
(x) is the fuzzy output value for universe of discourse value x. In our example, the output (K_new) becomes Output = 10 � [ 0.25 ( 1 ) + 0.75 ( 1.2 ) 0.25 + 0.75 ] ≈ 11.50 Once the three steps of fuzzification, rule evaluation, and defuzzification are finished and the output has been calculated, the process is repeated again for new set of Er_new%.
In the above example, after the first 1000 sec, the adaptive algorithm calculates a new gain of K_new=11.50. This new gain is used for the next 1000 sec (i.e. from t=1000 to 2000 sec in real time) by the PID control loop. At t=1001 sec, counter Er_new is set to zero to perform counting for the next 1000 seconds. At the end of another 1000 seconds (ie. at t=2000 seconds), Er_new% is calculated again.
Suppose this time, Er_new% happens to be 25. This means, by changing K from 10 to 11.5, the control became worse. Therefore, it would be better to change gain in the other direction, i.e., decrease the gain rather than increase. Thus, at t=2000 sec, Er_new%=25, Er_old%=60 (previous value of Er_new%), K_new=11.5 and K_old=10 (previous value of K). Applying Eq.(2), a negative �Dir� is obtained. With Er_new% of 25 and Dir=Negative, the fuzzy-logic calculation is performed again to calculate a new gain for the next 1000 seconds. The new value of gain is K_new=7.76 and is used from t=2000 to 3000 seconds by the PID Loop.
Suppose for the third iteration, i.e., from (t=2000 to 3000 seconds, Er_new% comes out to be 95% (which represents tighter control). Performing the same fuzzy-logic operation gives the same value of K_new, and the gain remains unchanged until Er_new% again degrades.
The control algorithm used in the loop is a Proportion-Integral (PI) control technique (PID). The PI algorithm calculates the valve position (0-100%) in case of ESR or calculates the percentage loading (0 to 100%) in case of PWM compressor. A typical integral reset time, Ti, for both the actuators is 60 seconds. The gain is tuned adaptively by the adaptive loop. The adaptive algorithm is turned off in the preferred embodiment whenever the system is in defrost; is going through pull-down; there a big set point change; sensor failure has been detected; or any other system failure is detected.
N-Close: Number of times Valve position /PWM loading was 0%. N-Open: Number of times Valve position/PWM loading was 100%. MAVP: The moving average of the Valve position /PWM loading for �tsum� seconds. SSLP: The steady-state Valve position /PWM loading is set equal to MAVP if for the �tsum� duration ER_new% is greater than 50%. dT: Moving average of the difference between Ta and Ti (Ta−Ti). SH: Moving average of the difference between To and Ti (To−Ti) in the said duration. This is approximately the evaporator superheat. N_FL: Number of times To was less than Ti during the said duration, i.e., �tsum� seconds. This number will indicate bow much the expansion valve is flooding the evaporator. In addition, Pull-down time after defrost, tpd, is also learnt. Based on these variables, the following diagnostics are performed: temperature sensor failure; degraded expansion valve; degraded ESR valve/PWM Compressor; oversized ESR/PWM; undersized ESR/PWM; and no air flow.
If an expansion valve sticks or is off-tuned or is undersized/oversized, the following combinations of the tracked variable can be used to diagnose such problems. N_FL>50% and ER_new%>10% indicate the expansion valve is stuck open or is off-tuned or may be even oversized and thus is flooding the evaporator coil. An alarm is sent upon such a condition. Moreover, SH>20 and N_FL=0% indicate an off-tuned expansion valve or an undersized valve or the valve is stuck closed.
If ER_new%>50% before defrost and during defrost Ti<32□ F. and SH>5□ F., then the valve is determined to be missing steps. Accordingly, the valve is closed by another 100% and if Ti and SH remain the same then this is highly indicative that the valve is stuck.
If ER_new%=0 and N_Close is 100% and Ti<32 F. and SH>5 F. then PWM/ESR is determined to be stuck open. If ER_new%=0 and N_Open is 100% and Ti>32 F. and SH>5 F. then PWM/ESR is determined to be stuck closed.
If N_Close>90% and 30%<ER_new%<100%, then an alarm is sent for oversized valve/PWM Compressor.
If N_Open>90% and ER_new%=0 and SH>5, then an alarm is sent for undersized valve/PWM Compressor.
If N_Open=100%, ER_new%=0, SH<5 F. and Ti<25 F and N_FL>50%, then either the air is blocked or the fans are not working properly.
Sampling Time (Ts) Control Type (P or T) Sensor Mode (Avg/Min/Max) Perform Analog to Digital Conversion (ADC)
on all (four) Temp. Sensor Channels output data as Counts Digitally Filter Counts
Ynew=0.75 * Yold+0.25 * Counts output data as Filtered Counts Convert Filtered Counts to Deg F.
Test if at least one Sensor is within normal operating limits e.g. within −40 and +90 F.
If none are within limit�Set Sensor Alarm to TRUE Else Perform Avg/Min/Max operation based on Sensor Mode If Control Type is NOT a T/P Control Type
Then End Signal Conditioning Routine (until next Ts cycle) Else (Control Type is T/P) Do the Following: Perform ADC on Pressure Sensor Channel
output data as Counts Digitally Filter Counts
Ynew=0.75 * Yold+0.25 * Counts output data as Filtered Counts Convert Filtered Counts to Psig
Test if pressure Sensor is within normal operating limits e.g. within 0 and +200
Set dP=dP Set Pt. Else:
Calculate dP=Pmax-Pmin Set Sensor Alarm to Conditioned T/dP
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Summary of the Office Action provided by Goodrich Riquelme Asociados law firm.7Rejection Decision regarding CN 200510064854.7 dated Feb. 6, 2009.8Second Office Action dated Apr. 17, 2009 regarding Application No. 200610128576.1 received from the Patent Office of the People's Republic of China translated by CCPIT Patent and Trademark Law Office.9Third Office Action dated Aug. 21, 2009 regarding Application No. 200610128576.1 received from the Patent Office of the People's Republic of China translated by CCPIT Patent and Trademark Law Office.10Third Office Action dated Oct. 16, 2009 regarding Application No. 200410085953.9 received from the Patent Office of the People's Republic of China (translated by Unitalen Attorneys at Law).Referenced byCiting PatentFiling datePublication dateApplicantTitleUS20120085512 *Oct 7, 2011Apr 12, 2012Audi AgVehicle cooling system* Cited by examinerClassifications U.S. Classification62/126, 62/217, 62/228.1International ClassificationF25B49/02, F04C27/00, A47F3/04, F25B1/04, G05D1/08, F04C18/02, F25B41/06, F25B41/04, G05D23/19, F01C1/02, F04C28/08, F25B5/02, F04C28/22, F04C28/18, F04C28/02, F04C28/28, F04C28/00, F04C28/26, F25B49/00, F04C28/06, F04B49/06Cooperative ClassificationF25B2700/2106, F25B2341/0653, F25B2700/21174, A47F3/04, F25B2700/21175, F04C2270/015, F25B2600/0261, F04C28/22, F04C23/008, F25B5/02, F04C18/0215, F04C28/28, F04C28/06, F04C28/00, F04C27/005, Y02B30/72, F25B41/043, F25B49/022, F25B1/04, F25B49/005, G05D23/1909, F25B2400/22, F25B2700/1933, F25B41/062, F04C28/265, F25B2700/193, F04C2270/86, F04C28/02, F04C28/08, F25B2700/2117European ClassificationF04C28/08, F25B49/00F, F04C28/26B, A47F3/04, F04C28/22, F25B5/02, F04C28/06, G05D23/19C2, F25B49/02B, F04C18/02B2, F04C28/02, G05D1/08B4, F25B41/04B, F04C28/28, F04C27/00C, F25B1/04, F04C28/00Legal EventsDateCodeEventDescriptionJun 30, 2014FPAYFee paymentYear of fee payment: 12Apr 26, 2007ASAssignmentFree format text: CERTIFICATE OF CONVERSION, ARTICLES OF FORMATION AND ASSIGNMENT;ASSIGNOR:COPELAND CORPORATION;REEL/FRAME:019215/0273Effective date: 20060927Owner name: EMERSON CLIMATE TECHNOLOGIES, INC., OHIORotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services