This work gives a comprehensive overview of the achievements in the field of modeling and active control of instabilities in compressions systems over the last decade.

Existing models of unstable compression systems are in most cases restricted to constant speed compressors. Here, two models are derived that take time varying rotational speed into account - one for centrifugal compressors and one for axial compressors.

. The main focus of the modeling element is the inclusion of non-constant speed in existing dynamic models of unstable compression systems, and the study of surge and rotating stall in connection with this.

. The focus of the control element is the use of a close coupled valve as a means of stabilising surge and rotating stall. Little work has yet been published on this.

Using techniques such as backstepping and passivity, controllers for a close coupled valve in the compression system are derived in order to stabilise the compressors and extend the range of mass flows over which it can be operated stably. Detailed analysis of the closed loop systems is performed and many case studies with simulations are presented.

Scientists and graduate students working in this area will find this particularly useful. It will also be a valuable addition to libraries and the industry as a whole.

Advances in Industrial Control aims to report and encourage the transfer of technology in control engineering. The rapid development of control technology has an impact on all areas of the control discipline. The series offers an opportunity for researchers to present an extended exposition of new work in all aspects of industrial control.

The series Advances in Industrial Control aims to report and encourage technology transfer in control engineering. The rapid development of control technology impacts all areas of the control discipline. New theory, new controllers, actuators, sensors, new industrial processes, computer methods, new applications, new philosophies . . . , new challenges. Much of this development work resides in industrial reports, feasibility study papers and the reports of advanced collaborative projects. The series offers an opportunity for researchers to present an extended exposition of such new work in all aspects of industrial control for wider and rapid dissemination. Operating plant as close as possible to constraint boundaries so often brings economic benefits in industrial process control. This is the conundrum at the heart of this monograph by Tommy Gravdahl and Olav Egeland on stall control for compressors. Operation of the compressor closer to the surge line can increase operational efficiency and flexibility The approach taken by the authors follows the modern control system paradigm: -physical understanding, detailed modelling and simulation studies and finally control studies. The thoroughness of the presentation, bibliography and appendices indicates that the volume has all the hallmarks of being a classic for its subject. Despite the monograph's narrow technical content, the techniques and insights presented should appeal to the wider industrial control community as well as the gas turbine/compressor specialist. M. J. Grimble and M. A.

1 Compressor Surge and Stall: An Introduction.- 1.1 Introduction.- 1.2 Compressors.- 1.2.1 Types of compressors.- 1.2.2 The axial compressor, principles of operation.- 1.2.3 The centrifugal compressor, principles of operation.- 1.3 Application of compressors.- 1.3.1 Gas turbines and jet engines for propulsion and power generation.- 1.3.2 Compression in the process industry.- 1.3.3 Transportation of gases and fluids in pipelines.- 1.3.4 Supercharging of internal combustion engines.- 1.4 Stability of Compression Systems.- 1.4.1 Surge.- 1.4.2 Rotating Stall.- 1.4.3 Other instabilities.- 1.5 Previous work on modeling of axial compression systems.- 1.5.1 Why model compression systems?.- 1.5.2 The model of Greitzer (1976).- 1.5.3 The model of Moore and Greitzer (1986).- 1.5.4 Other models.- 1.6 Previous work on modeling of centrifugal compr. systems.- 1.6.1 Greitzer-type models for centrifugal compressors.- 1.6.2 Other models.- 1.7 Jet engine and gas turbine models.- 1.8 Previous work on surge/stall avoidance.- 1.8.1 Background and motivation.- 1.8.2 Industrial solutions to surge avoidance.- 1.9 Active Control of Surge and Rotating Stall.- 1.9.1 Background and motivation.- 1.9.2 Control of surge in centrifugal and axial compressors.- 1.9.3 Control of surge and rotating stall in axial compressors.- 1.10 Sensor/actuator selection in surge/stall control.- 1.10.1 Motivation.- 1.10.2 Selection of sensors and actuators for surge control.- 1.10.3 Selection of sensors and actuators for rotating stall control.- 1.10.4 Actuator requirements.- 2 CCV Control of Surge and Rotating Stall for the MG Model.- 2.1 Introduction.- 2.1.1 Motivation and main idea.- 2.1.2 Previous work.- 2.2 Preliminaries.- 2.2.1 The Model of Moore and Greitzer.- 2.2.2 Close Coupled Valve.- 2.2.3 Equilibria.- 2.2.4 Change of Variables.- 2.2.5 Disturbances.- 2.3 Surge Control.- 2.3.1 Undisturbed Case.- 2.3.2 Determination of ?0.- 2.3.3 Time Varying Disturbances.- 2.3.4 Adaption of Constant Disturbances.- 2.4 Control of Rotating Stall.- 2.4.1 Undisturbed Case.- 2.4.2 Disturbed Case.- 2.5 Simulations.- 2.5.1 Surge Control.- 2.5.2 Rotating Stall Control.- 2.6 Conclusion.- 3 Passivity Based Surge Control.- 3.1 Introduction.- 3.1.1 Motivation.- 3.1.2 Notation.- 3.2 Model.- 3.3 Passivity.- 3.3.1 Passivity of Flow Dynamics.- 3.3.2 Passivity of Pressure Dynamics.- 3.3.3 Control Law.- 3.4 Disturbances.- 3.5 Simulations.- 3.6 Concluding Remarks.- 4 A MG Model for Axial Compr. with Non-constant Speed.- 4.1 Introduction.- 4.2 Preliminaries.- 4.3 Modeling.- 4.3.1 Spool Dynamics.- 4.3.2 Compressor.- 4.3.3 Entrance Duct and Guide Vanes.- 4.3.4 Exit Duct and Guide Vanes.- 4.3.5 Overall Pressure Balance.- 4.3.6 Plenum Mass Balance.- 4.3.7 Galerkin Procedure.- 4.3.8 Final Model.- 4.4 Simulations.- 4.4.1 Unstable Equilibrium, ? = 0.5.- 4.4.2 Stable Equilibrium ? = 0.65.- 4.5 Concluding Remarks.- 5 Modelling and Control of Surge for a Centrifugal Compressor with Non-constant Speed.- 5.1 Introduction.- 5.2 Model.- 5.2.1 Impeller.- 5.2.2 Diffuser.- 5.3 Energy Transfer.- 5.3.1 Ideal Energy Transfer.- 5.3.2 Slip.- 5.3.3 Compressor Torque.- 5.3.4 Incidence Losses.- 5.3.5 Frictional Losses.- 5.3.6 Efficiency.- 5.4 Energy Transfer and Pressure Rise.- 5.5 Choking.- 5.6 Dynamic Model.- 5.7 Surge Control Idea.- 5.8 Controller Design and Stability Analysis.- 5.9 Simulations.- 5.10 Conclusion.- 6 Concluding remarks and further research.- 6.1 Conclusions.- 6.2 Further research.- 6.2.1 Mass flow measurements.- A Stability of the Greitzer model.- B Nomenclature.- C Some Thermodynamic and Fluid Mechanical Relations.- C.1 Flow and Pressure Coefficients.- C.2 Isentropic Processes.- C.3 Mass Balance of the Plenum.- C.4 Flow through a Nozzle.- C.5 Compressor Pressure Rise.- D Including a CCV in the Moore-Greitzer Model.- E Numerical Values Used in Simulations.- F Bounds on the Controller Parameters of Theorem 2.5.