Variable speed compressor based AC system and control method

Abstract

The present disclosure relates to the field of air conditioning technology. In particular, it involves a control method and control system based on a variable speed AC compressor.

Claims

1. A variable speed AC control system for cooling or heating comprises: speed control calculator and database unit, wherein the speed control calculator is configured for producing an optimal compressor speed value based on step 1, considering user's performance and energy saving preferences to determine a timing for a conventional off-on-off operation signaling and timing cycle and step 2, based on the timing in step 1 calculating indoor load in thermal units in the conventional off-on-off operation signaling and timing cycle; and step 3, matching the indoor load and an AC output in thermal units with the conventional off-on-off operation signaling and timing cycle, having one compressor speed for one given timing cycle so that the indoor load equals the AC output within the conventional off-on-off operation signaling and timing cycle determined in step 1.

2. The variable speed AC control system according to claim 1, wherein the database unit is configured for storing and providing indoor load coefficient and outdoor temperature lookup data, which are needed by the speed control calculator.

3. The variable speed AC control system according to claim 2, wherein the control system is configured for acquiring sensor data generated by outdoor unit, including outdoor aft temperature, outdoor unit liquid outlet temperature, compressor return inlet temperature, compressor discharge temperature, values of compressor high pressure and low pressure.

4. The variable speed AC control system according to claim 3, wherein the speed control calculator further comprises of indoor calculator for calculating the total load for the operation timing cycle; and output calculator for calculating the total output for the operation timing cycle.

5. The variable speed AC control system according to claim 4, wherein the speed control calculator calculates actual indoor load coefficient for actual operation timing cycle, where this actual bad coefficient, the corresponding actual operation timing cycle and actual average temperature would be used to update the lookup data.

6. The variable speed AC control system according to claim 5, wherein when the actual operation timing cycle is greater than a targeted operation timing, increases the output.

7. The variable speed AC control system according to claim 5, wherein the control system is configured to obtain in advance outdoor temperature values.

8. A variable speed AC control method for cooling or heating, comprising: producing an optimal compressor speed value based on step 1, considering user's performance and energy saving preferences to determine a timing for a conventional off-on-off operation signaling and timing cycle; and step 2, based on the timing in step 1 determining indoor bad in thermal in the conventional off-on-off operation signaling and timing cycle; and step 3, matching the indoor load and an AC output in thermal units with the conventional off-on-off operation signaling and timing cycle, having one compressor speed for one given timing cycle so that the indoor bad equals the AC output within the conventional off-on-off operation signaling and timing cycle determined in step 1.

9. The variable speed AC control method according to claim 8, further comprising: calculating total indoor load and total output for the given operation signaling and timing cycle; and resetting the AC compressor speed so that the total output matches the total indoor load.

10. The variable speed AC control method according to claim 9, wherein the calculation of total indoor load is based on retrieving from load coefficient/temperature lookup table values and adding up the off-on period total load and on-off period total load.

11. The variable speed AC control method according to claim 10, wherein the coefficient/temperature lookup data is from prior recorded output data, where such output data is calculated based on outdoor air temperature, outdoor unit liquid outlet temperature, compressor return inlet temperature, compressor discharge temperature, values of compressor high pressure and low pressure.

12. The variable speed AC control method according to claim 11, further comprising: re-determining periodically updated output value, comparing that with updated total load value, in order to reset the AC compressor speed so the total output matches the total load.

13. The variable speed AC control method according to claim 12, further comprising: responding when the off signal does not arrive at the end of the targeted operation timing cycle, by increasing the output in order to compensate a higher than expected load.

14. The variable speed AC control method according to claim 13, further comprising: re-determining the updated total load value based on actual outdoor temperatures at prior successive re-determining timing periods and based on projecting current temperature being constant until the end of the operating cycle.

15. The variable speed AC control method according to claim 14, further comprising: responding to possible inaccurate coefficient values when the end of operation off signal is given due to interruption, by utilizing data management method such as averaging or setting a confidence level.

16. A non-transitory computer-readable medium having stored thereon a set of computer-executable instructions for causing a first device to perform steps comprising: producing an optimal compressor speed value based on step 1, considering user's performance and energy saving preferences to determine a timing for a conventional off-on-off operation signaling and timing cycle; and step 2, based on the timing in step 1 determining indoor load in thermal units in the conventional off-on-off operation signaling and timing cycle; and step 3, matching the indoor load and an AC cycle, having one compressor speed for one given timing cycle so that the indoor load equals the AC output within the conventional off-on-off operation signaling and timing cycle determined in step 1.

17. The non-transitory computer-readable medium having stored thereon a set of computer-executable instructions for causing the first device to perform steps according to claim 16, further comprising: calculating total indoor load and total output for the given operation signaling and timing cycle; and resetting the AC compressor speed so that the total output matches the total indoor load.

18. The non-transitory computer-readable medium having stored thereon a set of computer-executable instructions for causing the first device to perform steps according to claim 17, wherein the calculation of total indoor load is based on retrieving from load coefficient/temperature lookup table values and adding up the off-on period total load and on-off period total load.

19. The non-transitory computer-readable medium having stored thereon a set of computer-executable instructions for causing the first device to perform steps according to claim 18, wherein the coefficient/temperature lookup data is from prior recorded output data, where such output data is calculated based on outdoor air temperature, outdoor unit liquid outlet temperature, compressor return inlet temperature, compressor discharge temperature, values of compressor high pressure and low pressure.

20. The non-transitory computer-readable medium having stored thereon a set of computer-executable instructions for causing the first device to perform steps according to claim 19, further comprising: re-determining periodically updated output value, comparing that with updated total load value, in order to reset the AC compressor speed so the total output matches the total load.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows an AC compressor operation cycle of this disclosure.

(2) FIG. 2 shows a system diagram of the new variable AC unit implementation of this disclosure.

(3) FIG. 3 shows configuration diagram how the new variable AC control unit fits into the overall AC system implementation.

(4) FIG. 4 shows a flowchart of a first embodiment of this disclosure, on how to get the total indoor load.

(5) FIG. 5 shows the first embodiment of this disclosure, on how optimal speed is determined in the variable speed system.

(6) FIG. 6 shows a variable control unit diagram of a second embodiment of this disclosure.

(7) FIG. 7 shows a flowchart on how to observe the indoor load in the second embodiment of this disclosure.

(8) FIG. 8 shows a flowchart on when to maximize speed in the second embodiment of this disclosure.

DETAILED DESCRIPTION OF THE DISCLOSURE

First Embodiment

(9) FIG. 3 is the variable speed AC control system configuration diagram of the first embodiment, comprises: speed control calculation unit 10, database unit 20, operation data acquisition unit 30 and network communication module 40, wherein

(10) the speed control calculation unit 10 is for calculating the indoor load coefficient n, total indoor load N, system capacity q and total system output Q, and based on the comparing the total indoor load N and total cooling output Q, produce an optimal compressor speed value; and

(11) database unit 20, for storing and providing the indoor load coefficient n/outdoor temperature lookup data, as well as the compressor timing of the operating cycle, which are needed by the speed control calculation unit 10; and

(12) the operation data acquisition unit 30, for acquiring sensor data generated by the outdoor unit, including outdoor air temperature T, outdoor unit liquid outlet temperature T.sub.out, compressor return inlet temperature T.sub.in, compressor discharge temperature T.sub.dis, the value of the compressor high pressure PH and the low pressure PL; and

(13) the network communication unit 40 is used to get weather forecasts results from a remote server, used to obtain in advance ambient temperature for the t.sub.0 to t.sub.2 period; and

(14) the speed control calculation unit 10 includes an indoor unit 110 to calculate the total load, and an output unit 120 for calculating total cooling/heating output capacity; and

(15) the indoor unit 110 for calculating the total load of N from the t.sub.0 to t.sub.2 period; and

(16) the output unit 120 for calculating total cooling/heating output capacity Q from the t.sub.1 to t.sub.2 period.

t.SUB.1 .to t.SUB.2 .Period Determination

(17) The t.sub.1 to t.sub.2 period determination is based on goal setting. This is because if the period is set to shorter, it means greater the load, and greater the corresponding output. Negatively, the electrical consumption is also greater. Therefore, setting of t.sub.1 to t.sub.2 period can be set according to user's cooling/heating performance demand or energy-saving preference. But it can also be set by a remote server.

Total Indoor Load Calculation

(18) In this embodiment, the variable speed AC compressor control method uses the results of weather forecast to calculate the total indoor load N. The logic of this calculation depends on at least knowing the future t.sub.1 to t.sub.2 outdoor temperature change, before starting the AC compressor. As shown in FIG. 4, the steps for calculation of indoor total load are: a. on AC compressor starting time t.sub.1, retrieving the timing from the prior stopping time t.sub.0 to the new starting time t.sub.1; b. calculating the average outdoor temperature of t.sub.0 to t.sub.1 as T.sub.a1; c. from the n-T.sub.a lookup table, determining the total indoor load of N.sub.1 from t.sub.0 to t.sub.1; d. from the weather forecast, receiving the outdoor temperature change information between t.sub.1 to t.sub.2 period; e. calculating the average outdoor temperature; f. from the n-T.sub.a lookup table, determine the total indoor load of N.sub.2 from t.sub.1 to t.sub.2; g. calculate the total indoor load of N=N.sub.1+N.sub.2 from t.sub.0 to t.sub.2;

Total Cooling/Heating Output Calculation

(19) When AC compressor is operating between t.sub.1 to t.sub.2, and assuming the current time is t, then the total cooling/heating output of Q.sub.1 from t.sub.1 to t can be expressed as:
.sub.t1.sup.tq(t)dt.

(20) Also assuming the output is constant as q(t) from t to t.sub.2, then the total cooling/heating output of Q.sub.2 from t to t.sub.2 can be expressed as:
q(t)(t.sub.2t).

(21) Therefore, the total cooling/heating output Q from t.sub.1 to t.sub.2 should be Q=Q.sub.1+Q.sub.2, which is:
.sub.t1.sup.tQ(t)dt+Q(t)(t.sub.2t).

AC Speed Control Method

(22) As FIG. 5 shows, an AC speed control method in this embodiment can be said to be comprised of these steps: a. receiving start signal for the AC compressor, then start the compressor; b. obtaining a targeted starting low pressure of Pes (in cooling mode), or high pressure of Pcs (in heating mode); c. determining whether stop signal for the AC compressor is receivedif true, then go to step iif not, then continue to step d; d. obtaining total indoor cooling/heating load N during targeted period; e. obtaining total compressor cooling/heating output Q for the targeted period; f. determining whether the total indoor cooling/heating load N is greater than the total outputif yes, then lower the low pressure of Pes by one pressure unit in cooling mode, or increase the high pressure of Pcs in heating mode, and go to step hif not, then go to step g; g. determining whether the total indoor cooling/heating load N is less than the total outputif yes, then increase the low pressure of Pes by one pressure unit in cooling mode, or lower the high pressure of Pcs in heating modeif not, then keep Pes or Pcs the same; h. based on the Pes (in cooling mode), or the Pcs (in heating mode) value, performing compressor PID (proportional, integral, and derivative) control, adjusting the compressor operation speed, and running the compressor for one timing cycle before the next speed redetermination, and then return to step c; i. calculating outdoor average temperature T.sub.a from t.sub.0 to t.sub.2 timing; j. based on the t.sub.0 to t.sub.2 timing, and the total compressor output Q, obtaining the actual total indoor load coefficient n from the t.sub.0 to t.sub.2 timing; k. determining whether the total indoor load coefficient n is within a reliable rangeif yes, then update the nT.sub.a lookup table before shutting down the compressorif not, shut down the compressor without updating.

(23) In the above-described control method, the targeted starting compressor speed in each cycle can be adjusted according to the actual working conditions. The cycle timing can be adjusted according to the actual working conditions as well.

(24) Based on this embodiment, the beneficial effects of the present disclosure is that one can obtain precise speed control in the variable speed AC compressor, all under the same conventional switching scheme where only the on/off signals are sent to the outdoor unit by the indoor unit or the thermostat.

Second Embodiment

(25) FIG. 6 is the variable speed AC control system configuration diagram of the second embodiment, comprises: speed control calculation unit 101, database unit 201, and operation data acquisition unit 301 wherein

(26) the speed control calculation unit 101 is for calculating the indoor load coefficient n, total indoor load N, system capacity q and total system output Q, and based on the comparing the total indoor load N and total cooling output Q, producing an optimal compressor speed value; and

(27) database unit 201, for storing and providing the indoor load coefficient n/outdoor temperature lookup data, as well as the compressor timing of the operating cycle, which are needed by the speed control calculation unit 101; and

(28) the operation data acquisition unit 301, for acquiring sensor data generated by the outdoor unit, including outdoor air temperature T, outdoor unit liquid outlet temperature T.sub.out, compressor return inlet temperature T.sub.in, compressor discharge temperature T.sub.dis, the value of the compressor high pressure PH and the low pressure PL; and

(29) the speed control calculation unit 101 includes an indoor unit 111 and an output unit 121; and

(30) the indoor unit 111 is for calculating the total load of N from the t.sub.0 to t.sub.2 period; and

(31) the output unit 121 is for calculating total cooling/heating output capacity Q from the t.sub.1 to t.sub.2 period.

t.SUB.1 .to t.SUB.2 .Period Determination

(32) The t.sub.1 to t.sub.2 period determination is the same as that in Embodiment 1.

Total Indoor Load Calculation

(33) In this embodiment, the variable speed AC compressor control method updates the load coefficient value from t.sub.0 to t.sub.2 based on varying outdoor temperatures. As compared to Embodiment 1, it does not rely on the weather forecast. Therefore, it does not need a network communication module. Moreover, the calculated indoor load under such method can change according to the changing temperatures. As shown in FIG. 7, the steps for calculation of indoor total load are: a. on AC compressor starting time t.sub.1, retrieving from the prior stopping time t.sub.0 to the new starting time t.sub.1, timing information on various outdoor temperatures, as well as the load coefficient n under the various outdoor temperatures; b. calculating the total indoor load N.sub.1 from t.sub.0 to t.sub.1 by adding up the load calculations from the various temperature and timing; c. determining the total indoor load of N.sub.2 from t.sub.1 to t.sub.2 by taking period load coefficient based on temperature at t.sub.1 from the n-T.sub.a lookup table; d. calculating the total indoor load of N=N.sub.1+N.sub.2 from t.sub.0 to t.sub.2; e. determining whether the stop signal is receivedif not, then go to step fif yes, then stop; f. determining whether the outdoor temperature has changedif not, go back to step eif yes, then go to step g; g. assuming the load coefficient n(T.sub.x) at t.sub.x when the temperature is changed is different from the prior n(T.sub.a), using n(T.sub.x) for calculating the total load for the rest of period from t.sub.x to t.sub.2, and updating the resulting new N.sub.2 before returning to step d.

Total Cooling/Heating Output Calculation

(34) The total indoor load calculation is the same as that in Embodiment 1.

AC Speed Control Method

(35) As FIG. 8 shows, an AC speed control method in this embodiment can be said to be similar to that in Embodiment 1, except that there is an additional treatment when arriving at the targeted t.sub.2 and the compressor still has not received a stop signal.

(36) This enhanced method comprises: a. receiving start signal for the AC compressor, start the compressor; b. obtain a targeted starting compressor speed; c. determining whether the time is t.sub.2if yes, go to step iif not, go to step d; d. obtaining total indoor cooling/heating load N during targeted period; e. obtaining total compressor cooling/heating output Q for the targeted period; f. determining whether the total indoor cooling/heating load N is greater than the total outputif yes, then increase the compressor speedif not, then go to step g; g. determining whether the total indoor cooling/heating load N is less than the total output Qif yes, then lower the targeted compressor speedif not, then keep the same compressor speed; h. run the compressor for one timing cycle before the next speed redetermination, and then return to step c; i. determining whether stop signal for the AC compressor is receivedif true, then stopif not, then continue to step j; j. forcing the compressor output to the maximum; k. run the compressor for one timing cycle before the next speed redetermination, and then return to step i.

(37) The control method described above is improved upon that of Embodiment 1. Given that when the time t.sub.2 arrives, if the compressor stop signal has not been received, that means the compressor output has not been high enough to satisfied the indoor temperature need. Therefore, the situation requires higher compressor output, in order to cool down and trigger the compressor stop signal as quickly as possible. This embodiment uses a maximum operation speed to increase the compressor output as the remedial approach, but to person ordinary skilled in the art, other remedial approaches are possible, such as increasing the speed steadily in each successive speed redetermination cycle.

(38) Based on this embodiment, the beneficial effects of the present disclosure is that one can obtain precise speed control in the variable speed AC compressor, all under the same conventional switching scheme where only the on/off signals are sent to the outdoor unit by the indoor unit or the thermostat.