Burn Control in Fusion Reactors Using Simultaneous Boundary and Distributed Actuation
52nd IEEE Conference on Decision and Control
Florence, Italy, December 10-13, 2013
| Abstract |
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The control of the plasma density and temperature profiles is one of the fundamental problems in nuclear fusion reactors. During reactor operation, the spatial profiles of deuterium-tritium fuel, alpha particles generated by fusion reactions, and energy must be precisely regulated. In this work we combine distributed actuation with a backstepping boundary control law to stabilize an unstable equilibrium in a burning plasma. Disturbance estimation update laws are included to improve disturbance rejection and tracking. A one-dimensional approximation of the transport equation for energy, as well as for the densities of deuterium-tritium fuel ions and alpha particles, is represented in cylindrical coordinates by a system of partial differential equations (PDEs). The PDE system is discretized in space using a finite difference method and a backstepping design is applied to obtain a discrete transformation from the original system into a particular target system chosen to facilitate the use of additional actuators distributed throughout the plasma. Numerical simulations show that a controller designed on a very coarse grid can stabilize the system and that distributed actuation improves the system response.