Method for determining the operating point

1. A method for determining the operating point of an electric motor-driven fan in a system, wherein the method comprises:

providing at least one startup of the fan, the at least one startup being a forward-rotation startup or a reverse-rotation startup;

measuring motor parameters M i and/or M i,R for a plurality of speeds during the at least one startup; determining technical flow parameters P i,v and/or P i,R for the plurality of speeds; and determining a clear correlation between the technical flow parameters P i,v and the motor parameters during forward rotation is not possible or a clear correlation between the technical flow parameters P i,R and the motor parameters M i,R during reverse rotation is not possible, such that the operating point cannot be determined; and in response to determining the operating point cannot be determined, a first domain D 1 and a second domain D 2 are defined in a curve diagram for the fan, between two polynomial functions, which intersect in each case at one of two possible operating points A 1,v and A 2,v , respectively, during forward operation of the fan; wherein P i,v is then referred to as P j,i,v with the subscript j being a 1 or 2 to reflect the first domain D 1 or the second domain D 2 , and the subscript v refers to the forward-rotation startup and the subscript R refers to the reverse-rotation startup; wherein recorded duty points during forward rotation are compared with first domain D 1 and second domain D 2 , the subscript j is a 1 or 2 to reflect the first domain D 1 or the second domain D 2 , and

i). a first determination is made that at least one of the recorded duty points or B 1,i,v (i=1, . . . , m−1) lies outside of the defined first domain D 1 and further, or

a second determination is made that all of the recorded duty points (i=1, . . . , m−1) lie within the second domain D 2 ,

in response to the first or second determination, the operating point is determined as A 2,v ,

or

ii). a third determination is made that at least one of the recorded duty points B 2,i,v (i=1, . . . , m−1) lies outside of the defined second domain D 2 , or

a fourth determination is made that all of the recorded duty points B 1,i,v (i=1, . . . , m−1) lie within the first domain D 1 ,

in response to the third or fourth determination, the operating point is determined as A 1,v , wherein the subscript i refers to the plurality of speeds.

2. The method according to claim 1 , wherein one startup is performed, and the one startup is a forward-rotation startup.

3. The method according to claim 1 , wherein one startup is performed, and the one startup is a reverse-rotation startup.

4. The method according to claim 1 , wherein two startups are performed, and the two startups correspond to a forward-rotation startup and a reverse-rotation startup, in a desired sequence.

5. The method according to claim 1 , wherein a clear correlation between the technical flow parameters P i,R and the motor parameters M i,R exists during reverse rotation and a forward-rotation startup has been carried out, then a system compensation curve f forward,1 (P 1,i,v ) through duty points B 1,i,v and a system compensation curve f forward,2 (P 2,i,v ) through duty points B 2,i,v from the forward-rotation startup and a system compensation curve f reverse (P i,R ) through duty points B i,R from the reverse-rotation startup are used to determine the operating point.

6. The method according to claim 2 , wherein no clear correlation between the technical flow parameters P i,v and the motor parameters M i,v during forward rotation exists, a first domain D 1 and a second domain D 2 are defined in a curve diagram for the fan, in each case between two polynomial functions, which intersect in each case at one of two possible operating points A 1,v and A 2,v , respectively, during forward operation of the fan;

wherein P i,v may be written as P j,i,v with the subscript j being a 1 or 2 to reflect the first domain D 1 or the second domain D 2 .

7. The method according to claim 3 , wherein no clear correlation between the technical flow parameters P i,v and the motor parameters M i,v during forward rotation exists, a first domain D 1 and a second domain D 2 are defined in a curve diagram for the fan, in each case between two polynomial functions, which intersect in each case at one of two possible operating points A 1,v and A 2,v , respectively, during forward operation of the fan;

wherein P i,v may be written as P j,i,v with the subscript j being a 1 or 2 to reflect the first domain D 1 or the second domain D 2 .

8. The method according to claim 4 , wherein no clear correlation between the technical flow parameters P i,v and the motor parameters M i,v during forward rotation exists, a first domain D 1 and a second domain D 2 are defined in a curve diagram for the fan, in each case between two polynomial functions, which intersect in each case at one of two possible operating points A 1,v and A 2,v , respectively, during forward operation of the fan;

wherein P i,v may be written as P j,i,v with the subscript j being a 1 or 2 to reflect the first domain D 1 or the second domain D 2 .

9. The method according to claim 6 , wherein recorded duty points B j,i,v during forward rotation are compared with first domain D 1 and second domain D 2 , wherein the subscript j is a 1 or 2 to reflect the first domain D 1 or the second domain D 2 , and

when at least one of the recorded duty points B 1,i,v (i=1, . . . , m−1) lies outside of the defined first domain D 1 and further, when all of the recorded duty points B 2,i,v (i=1, . . . , m−1) lie within the second domain D 2 , the operating point is determined as A 2,v , and

when at least one of the recorded duty points B 2,i,v (i=1, . . . , m−1) lies outside of the defined second domain D 2 , and further, when all of the recorded duty points B 1,i,v (i=1, . . . , m−1) lie within the first domain D 1 , the operating point is determined as A 1,v .

10. The method according to claim 9 , wherein a clear correlation between the technical flow parameters P i,R and the motor parameters M i,R during reverse rotation exists and a forward-rotation startup has been carried out, then a system compensation curve f forward,1 (P 1,i,v ) through duty points B 1,i,v and a system compensation curve f forward,2 (P 2,i,v ) through duty points B 2,i,v from the forward-rotation startup and a system compensation curve f reverse (P i,R ) through duty points B i,R from the reverse-rotation startup are used to determine the operating point.

11. The method according to claim 7 , wherein recorded duty points B j,i,v during forward rotation are compared with first domain D 1 and second domain D 2 , wherein the subscript j is a 1 or 2 to reflect the first domain D 1 or the second domain D 2 , and

when at least one of the recorded duty points B 1,i,v (i=1, . . . , m−1) lies outside of the defined first domain D 1 and further, when all of the recorded duty points B 2,i,v (i=1, . . . , m−1) lie within the second domain D 2 , the operating point is determined as A 2,v , and

when at least one of the recorded duty points B 2,i,v (i=1, . . . , m−1) lies outside of the defined second domain D 2 , and further, when all of the recorded duty points B 1,i,v (i=1, . . . , m−1) lie within the first domain D 1 , the operating point is determined as A 1,v .

12. The method according to claim 11 , wherein a clear correlation between the technical flow parameters P i,R and the motor parameters M i,R during reverse rotation exists and a forward-rotation startup has been carried out, then a system compensation curve f forward,1 (P 1,i,v ) through duty points B 1,i,v and a system compensation curve f forward,2 (P 2,i,v ) through duty points B 2,i,v from the forward-rotation startup and a system compensation curve f reverse (P i,R ) through duty points B i,R from the reverse-rotation startup are used to determine the operating point.

13. The method according to claim 8 , wherein recorded duty points B j,i,v during forward rotation are compared with first domain D 1 and second domain D 2 , wherein the subscript j is a 1 or 2 to reflect the first domain D 1 or the second domain D 2 , and

when at least one of the recorded duty points B 1,i,v (i=1, . . . , m−1) lies outside of the defined first domain D 1 and further, when all of the recorded duty points B 2,i,v (i=1, . . . , m−1) lie within the second domain D 2 , the operating point is determined as A 2,v , and

when at least one of the recorded duty points B 2,i,v (i=1, . . . , m−1) lies outside of the defined second domain D 2 , and further, when all of the recorded duty points B 1,i,v (i=1, . . . , m−1) lie within the first domain D 1 , the operating point is determined as A 1,v .

14. The method according to claim 13 , wherein a clear correlation between the technical flow parameters P i,R and the motor parameters M i,R during reverse rotation exists and a forward-rotation startup has been carried out, then a system compensation curve f forward,1 (P 1,i,v ) through duty points B 1,i,v and a system compensation curve f forward,2 (P 2,i,v ) through duty points B 2,i,v from the forward-rotation startup and a system compensation curve f reverse (P i,R ) through duty points B i,R from the reverse-rotation startup are used to determine the operating point.

15. A method for determining the operating point of an electric motor-driven fan in a system, wherein the method comprises:

providing first startup of the fan, the first startup being a forward-rotation startup or a reverse-rotation startup;

measuring motor parameters M i,v or M i,R for a plurality of speeds during the startup;

determining technical flow parameters P i,v or P i,R for the plurality of speeds; and

determining that a clear correlation between the technical flow parameters P i and the motor parameters M i does not exist such that a determination of the operating point is not possible, and in response

providing a second startup of the fan, the second startup being opposite in direction of the first startup; and

determining an operating point of the fan based on the motor parameters measured from the first start up and the second startup;

wherein the subscript i refers to the plurality of speeds, the subscript v refers to the forward-rotation startup and the subscript R refers to the reverse-rotation startup.