Method and apparatus for load balancing among multiple compressors
AssigneeCompressor Controls Corporation
InventorsSerge Staroselsky, Brett W. Batson, Saul Mirsky, Vadim Shapiro
Life of this patent
Estimating the term…
Abstract
Balancing the load between compressors is not trivial. An approach is disclosed to balance loads for compression systems which have the characteristic that the surge parameters, S, change in the same direction with rotational speed during the balancing process. Load balancing control involves equalizing the pressure ratio, rotational speed, or power (or functions of these) when the compressors are operating far from surge. Then, as surge is approached, all compressors are controlled, such that they arrive at their surge control lines simultaneously.
Claims60
A method for controlling a compression system comprising at least two compressors, at least one driver, and a plurality of devices for varying the performance of said compressors, the method comprising the steps of:
- (a) defining a surge parameter, S, representing a distance between an operating point and a surge line for each compressor;
- (b) specifying a value, S.sub.*, of said surge parameter for each compressor;
- (c) manipulating the performance of said compressors to maintain a predetermined relationship between all compressors and/or drivers when the operating points of all compressors are farther from surge than said specified value, S.sub.*, wherein said predetermined relationship is not a function of S;
- and
- (d) manipulating the performance of said compressors in such a fashion that all compressors reach their surge lines simultaneously.
A method for controlling a compression system comprising at least two compressors, at least one driver, and a plurality of devices for varying the performance of said compressors, relief means, and instrumentation, the method comprising the steps of:
- (a) defining a surge parameter, S, representing a distance between an operating point and a surge line for each compressor;
- (b) calculating a value of S for each compressor based on signals from said instrumentation;
- (c) determining a maximum value, S.sub.max, of all values of S for all compressors;
- (d) specifying a value, S.sub.*, of said surge parameter for each compressor;
- (e) specifying a value, S.sub..delta., of said surge parameter as close or closer to surge than S.sub.* for each compressor;
- (f) constructing a function, .function..sub.2 (.multidot.), of pressure ratio, R.sub.c, for each compressor;
- (g) computing a value for the pressure ratio, R.sub.c, for each compressor;
- (h) calculating a value of a scaling factor, x, (0.ltoreq.x.ltoreq.1);
- (i) calculating a value which is a function of the state of said relief means, .function..sub.v (v);
- (j) calculating a value of a balancing parameter, B=(1-x).function..sub.2 (R.sub.c)+x1-.beta.(1-S)!1+.function..sub.v (v)!, for each compressor;
- (k) defining a value of a set point for said balancing parameter for each compressor;
- and
- (l) manipulating the performance of said compressors to match said balancing parameters to said set point for each compressor.
A method for controlling a compression system comprising at least two compressors, at least one driver, and a plurality of devices for varying the performance of said compressors, relief means, and instrumentation, the method comprising the steps of:
- (a) defining a surge parameter, S, representing a distance between an operating point and a surge line for each compressor;
- (b) calculating a value of S for each compressor based on signals from said instrumentation;
- (c) determining a maximum value, S.sub.max, of all values of S for all compressors;
- (d) specifying a value, S.sub.*, of said surge parameter for each compressor;
- (e) specifying a value, S.sub..delta., of said surge parameter as close or closer to surge than S.sub.* for each compressor;
- (f) constructing a function, .function..sub.2 (.multidot.), of power, P, for each compressor;
- (g) computing a value for the power, P, for each compressor;
- (h) calculating a value of a scaling factor, x, (0.ltoreq.x.ltoreq.1);
- (i) calculating a value which is a function of the state of said relief means, .function..sub.v (v);
- (j) calculating a value of a balancing parameter, B=(1-x).function..sub.2 (P)+x1-.beta.(1-S)!1+.function..sub.v (v)!, for each compressor;
- (k) defining a value of a set point for said balancing parameter for each compressor;
- and
- (l) manipulating the performance of said compressors to match said balancing parameters to said set point for each compressor.
A method for controlling a compression system comprising at least two compressors, at least one driver, and a plurality of devices for varying the performance of said compressors, relief means, and instrumentation, the method comprising the steps of:
- (a) defining a surge parameter, S, representing a distance between an operating point and a surge line for each compressor;
- (b) calculating a value of S for each compressor based on signals from said instrumentation;
- (c) determining a maximum value, S.sub.max, of all values of S for all compressors;
- (d) specifying a value, S.sub.*, of said surge parameter for each compressor;
- (e) specifying a value, S.sub..delta., of said surge parameter as close or closer to surge than S.sub.* for each compressor;
- (f) constructing a function, .function..sub.2 (.multidot.), of rotational speed, N, for each compressor;
- (g) computing a value for the rotational speed, N, for each compressor;
- (h) calculating a value of a scaling factor, x, (0.ltoreq.x.ltoreq.1);
- (i) calculating a value which is a function of the state of said relief means, .function..sub.v (v);
- (j) calculating a value of a balancing parameter, B=(1-x).function..sub.2 (N)+x1-.beta.(1-S)!1+.function..sub.v (v)!, for each compressor;
- (k) defining a value of a set point for said balancing parameter for each compressor;
- and
- (l) manipulating the performance of said compressors to match said balancing parameters to said set point for each compressor.
An apparatus for controlling a compression system comprising at least two compressors, at least one driver, and a plurality of devices for varying the performance of said compressors, the apparatus comprising:
- (a) means for defining a surge parameter, S, representing a distance between an operating point and a surge line for each compressor;
- (b) means for specifying a value, S.sub.*, of said surge parameter for each compressor;
- (c) means for manipulating the performance of said compressors to maintain a predetermined relationship between all compressors and/or drivers when the operating points of all compressors are farther from surge than said specified value, S.sub.*, wherein said predetermined relationship is not a function of S;
- and
- (d) means for manipulating the performance of said compressors in such a fashion that all compressors reach their surge lines simultaneously.
An apparatus for controlling a compression system comprising at least two compressors, at least one driver, and a plurality of devices for varying the performance of said compressors, relief means, and instrumentation, the apparatus comprising:
- (a) means for defining a surge parameter, S, representing a distance between an operating point and a surge line for each compressor;
- (b) means for calculating a value of S for each compressor based on signals from said instrumentation;
- (c) means for determining a maximum value, S.sub.max, of all values of S for all compressors;
- (d) means for specifying a value, S.sub.*, of said surge parameter for each compressor;
- (e) means for specifying a value, S.sub..delta., of said surge parameter as close or closer to surge than S.sub.* for each compressor;
- (f) means for constructing a function, .function..sub.2 (.multidot.), of pressure ratio, R.sub.c, for each compressor;
- (g) means for computing a value for the pressure ratio, R.sub.c, for each compressor;
- (h) means for calculating a value of a scaling factor, x, (0.ltoreq.x.ltoreq.1);
- (i) means for calculating a value which is a function of the state of said relief means, .function..sub.v (v);
- (j)) means for calculating a value of a balancing parameter, B=(1-x).function..sub.2 (R.sub.c)=x1-.beta.(1-S)!1+.function..sub.v (v)!, for each compressor;
- (k) means for defining a value of a set point for said balancing parameter for each compressor;
- and
- (l) means for manipulating the performance of said compressors to match said balancing parameters to said set point for each compressor.
An apparatus for controlling a compression system comprising at least two compressors, at least one driver, and a plurality of devices for varying the performance of said compressors, relief means, and instrumentation, the apparatus comprising:
- (a) means for defining a surge parameter, S, representing a distance between an operating point and a surge line for each compressor;
- (b) means for calculating a value of S for each compressor based on signals from said instrumentation;
- (c) means for determining a maximum value, S.sub.max, of all values of S for all compressors;
- (d) means for specifying a value, S.sub.*, of said surge parameter for each compressor;
- (e) means for specifying a value, S.sub..delta., of said surge parameter as close or closer to surge than S.sub.* for each compressor;
- (f) means for constructing a function, .function..sub.2 (.multidot.), of power, P, for each compressor;
- (g) means for computing a value for the power, P, for each compressor;
- (h) means for calculating a value of a scaling factor, x, (0.ltoreq.x.ltoreq.1);
- (i) means for calculating a value which is a function of the state of said relief means, .function..sub.v (v);
- (j) means for calculating a value of a balancing parameter, B=(1-x).function..sub.2 (P)+x1-.beta.(1-S)!1+.function..sub.v (v)!, for each compressor;
- (k) means for defining a value of a set point for said balancing parameter for each compressor;
- and
- (l) means for manipulating the performance of said compressors to match said balancing parameters to said set point for each compressor.
An apparatus for controlling a compression system comprising at least two compressors, at least one driver, and a plurality of devices for varying the performance of said compressors, relief means, and instrumentation, the apparatus comprising:
- (a) means for defining a surge parameter, S, representing a distance between an operating point and a surge line for each compressor;
- (b) means for calculating a value of S for each compressor based on signals from said instrumentation;
- (c) means for determining a maximum value, S.sub.max, of all values of S for all compressors;
- (d) means for specifying a value, S.sub.*, of said surge parameter for each compressor;
- (e) means for specifying a value, S.sub..delta., of said surge parameter as close or closer to surge than S.sub.* for each compressor;
- (f) means for constructing a function, .function..sub.2 (.multidot.), of rotational speed, N, for each compressor;
- (g) means for computing a value for the rotational speed, N, for each compressor;
- (h) means for calculating a value of a scaling factor, x, (0.ltoreq.x.ltoreq.1);
- (i) means for calculating a value which is a function of the state of said relief means, .function..sub.v (v);
- (j) means for calculating a value of a balancing parameter, B=(1-x).function..sub.2 (N)+x1-.beta.(1-S)!1+.function..sub.v (v)!, for each compressor;
- (k) means for defining a value of a set point for said balancing parameter for each compressor;
- and
- (l) means for manipulating the performance of said compressors to match said balancing parameters to said set point for each compressor.
Dependencies are inferred from the claim text.