2011 Particle Accelerator Conference - List of Authors (Ke, X.H.)

Paper	Title	Page
TUP182	In-situ System Identification for an Optimal Control of Magnet Power Supplies	1172
	X.H. Ke, F. Jenni FHNW, Windisch, Switzerland
	Funding: Paul Scherrer Institute, Switzerland In particle accelerators, the magnet power supply system (controller, power stage and magnet) normally has a higher system order (>5). An exact model, representing the behavior of such a system, would be very helpful for an optimal control. For the control, the engineers are mainly not interested in the analytic model, which shows the exact internal mechanisms of the physical system, but, in a model describing the I/O behavior. Moreover, since the real elements do not exactly correspond to the design values, it is desirable to model the power supply system by means of system identification from measured properties. For that, a subspace based identification method is applied, which yields the observer for the self-optimizing high dynamic control of magnet power supplies at the Paul Scherrer Institute (PSI). The only inputs the identification needs are the measured DC-link voltage, the magnet voltage and the magnet current. With that it calculates a corresponding state space model for the system. The whole process is done automatically and in situ, which is a practical and meaningful approach to obtain the exact system information for control design.

TUP183	Self-optimizing High Dynamic Power Supply Control	1175
	X.H. Ke, F. Jenni FHNW, Windisch, Switzerland H. Jäckle PSI, Villigen, Switzerland
	Funding: Paul Scherrer Institute, Switzerland In 1999, the first fully digitally controlled magnet power supplies were put into operation at PSI (Paul Scherrer Institute, Switzerland). Today, approximately 1000 are in use at PSI and a multiple of that worldwide. This project aims at developing a high performance control scheme for a better dynamic behavior of today's magnet powers supplies, without reducing their excellent static behaviors. The resulting control strategy, an in situ identification based observer, combined with state space and proportional integral (SS-PI) control, leads to a significantly improved dynamic behavior of the existing power supplies. The whole commissioning, including system identification, as well as control parameter determination and optimization, is done automatically on the DSP with support of a PC. The control strategy has been implemented on the existing PSI controller and a 10A-corrector power supply, together with various magnets, by updating the software and/or firmware only. Currently, the new control strategy is being implemented and tested at PSI on a second generation Digital Power Electronic Control System (DPC) controller card.

Paper

Title

Page

In-situ System Identification for an Optimal Control of Magnet Power Supplies

1172

X.H. Ke, F. Jenni
FHNW, Windisch, Switzerland

Funding: Paul Scherrer Institute, Switzerland
In particle accelerators, the magnet power supply system (controller, power stage and magnet) normally has a higher system order (>5). An exact model, representing the behavior of such a system, would be very helpful for an optimal control. For the control, the engineers are mainly not interested in the analytic model, which shows the exact internal mechanisms of the physical system, but, in a model describing the I/O behavior. Moreover, since the real elements do not exactly correspond to the design values, it is desirable to model the power supply system by means of system identification from measured properties. For that, a subspace based identification method is applied, which yields the observer for the self-optimizing high dynamic control of magnet power supplies at the Paul Scherrer Institute (PSI). The only inputs the identification needs are the measured DC-link voltage, the magnet voltage and the magnet current. With that it calculates a corresponding state space model for the system. The whole process is done automatically and in situ, which is a practical and meaningful approach to obtain the exact system information for control design.

TUP183

Self-optimizing High Dynamic Power Supply Control

1175

X.H. Ke, F. Jenni
FHNW, Windisch, Switzerland
H. Jäckle
PSI, Villigen, Switzerland

Funding: Paul Scherrer Institute, Switzerland
In 1999, the first fully digitally controlled magnet power supplies were put into operation at PSI (Paul Scherrer Institute, Switzerland). Today, approximately 1000 are in use at PSI and a multiple of that worldwide. This project aims at developing a high performance control scheme for a better dynamic behavior of today's magnet powers supplies, without reducing their excellent static behaviors. The resulting control strategy, an in situ identification based observer, combined with state space and proportional integral (SS-PI) control, leads to a significantly improved dynamic behavior of the existing power supplies. The whole commissioning, including system identification, as well as control parameter determination and optimization, is done automatically on the DSP with support of a PC. The control strategy has been implemented on the existing PSI controller and a 10A-corrector power supply, together with various magnets, by updating the software and/or firmware only. Currently, the new control strategy is being implemented and tested at PSI on a second generation Digital Power Electronic Control System (DPC) controller card.