Modeling and control of TCV

Sharma, A. S.; Limebeer, D.J.N.; Jaimoukha, Imad M.; Lister, J.B.

doi:10.1109/tcst.2004.841647

Cited by 24 publications

(17 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One of the main issues to overcome in the path to commercialization is the instabilities [15][16][17][18][19][20][21][22][23][24]. These instabilities cause disruptions, limiting the maximal achievable time for plasma confinement and making indispensable an optimal control system.…”

Section: System Descriptionmentioning

confidence: 99%

A Variable Structure Control Scheme Proposal for the Tokamak à Configuration Variable

et al. 2019

View full text Add to dashboard Cite

Fusion power is the most significant prospects in the long-term future of energy in the sense that it composes a potentially clean, cheap, and unlimited power source that would substitute the widespread traditional nonrenewable energies, reducing the geographical dependence on their sources as well as avoiding collateral environmental impacts. Although the nuclear fusion research started in the earlier part of 20th century and the fusion reactors have been developed since the 1950s, the fusion reaction processes achieved have not yet obtained net power, since the generated plasma requires more energy to achieve and remain in necessary particular pressure and temperature conditions than the produced profitable energy. For this purpose, the plasma has to be confined inside a vacuum vessel, as it is the case of the Tokamak reactor, which consists of a device that generates magnetic fields within a toroidal chamber, being one of the most promising solutions nowadays. However, the Tokamak reactors still have several issues such as the presence of plasma instabilities that provokes a decay of the fusion reaction and, consequently, a reduction in the pulse duration. In this sense, since long pulse reactions are the key to produce net power, the use of robust and fast controllers arises as a useful tool to deal with the unpredictability and the small time constant of the plasma behavior. In this context, this article focuses on the application of robust control laws to improve the controllability of the plasma current, a crucial parameter during the plasma heating and confinement processes. In particular, a variable structure control scheme based on sliding surfaces, namely, a sliding mode controller (SMC) is presented and applied to the plasma current control problem. In order to test the validity and goodness of the proposed controller, its behavior is compared to that of the traditional PID schemes applied in these systems, using the RZIp model for the Tokamak à Configuration Variable (TCV) reactor. The obtained results are very promising, leading to consider this controller as a strong candidate to enhance the performance of the PID-based controllers usually employed in this kind of systems.

show abstract

Section: System Descriptionmentioning

confidence: 99%

A Variable Structure Control Scheme Proposal for the Tokamak à Configuration Variable

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Considering a zero order hold discretization, the system (4) may be rewritten in matrix form as 1 ( 9 ) where is the manipulated variable that correspond to the plasma current, is the internal inductance and is the space state vector. Since this model has as input, it will be changed to suit a design purpose in which an integrator is embedded.…”

Section: Model Predictive Controlmentioning

confidence: 99%

Internal inductance predictive control for Tokamaks

Garrido

Romero

Garrido

et al. 2014

2014 World Automation Congress (WAC)

View full text Add to dashboard Cite

Control of the plasma inductance is an essential tool for the successful operation of Tokamaks in order to overcome stability issues as well as the new challenges specific to advanced scenarios operation. Thus, tokamak operation may benefit from model predictive control techniques to extend the pulse duration by reducing instabilities while guaranteeing tokamak integrity. The numerical results seem to indicate that internal inductance and current profiles can be adequately controlled which will influence the L-H transition timing, the density peaking and pedestal pressure. In this regard, the need for optimal, robust control emerges as a key factor in the development of a nuclear fusion reactor.

show abstract

“…The difference with the model found in the previous section is that now we will allow separate inputs for boundary and resistive voltages. Choosing a relative weight 1 k ≤ for B V , and a relative weight ( ) 1 k − for the R V input, the steady state solution of (58) is automatically guaranteed to match the steady state solution (28).…”

Section: Non Linear System Identificationmentioning

confidence: 99%

Development and validation of a tokamak skin effect transformer model

Romero¹,

Moret²,

Coda³

et al. 2012

Nucl. Fusion

View full text Add to dashboard Cite

A lumped parameter, state space model for the tokamak transformer including the slow flux penetration in the plasma (skin effect transformer model) is presented. The model does not require detailed or explicit information about plasma profiles or geometry. Instead, this information is lumped in system variables, parameters and inputs. The model has an exact mathematical structure built from energy and flux conservation theorems, predicting the evolution and non linear interaction of the plasma current and internal inductance as functions of the primary coil currents, plasma resistance, non-inductive current drive and the loop voltage at an specific location inside the plasma (equilibrium loop voltage). Loop voltage profile in the plasma is substituted by a three-point discretization, and ordinary differential equations are used to predict the equilibrium loop voltage as function of the boundary and resistive loop voltages. This provides a model for equilibrium loop voltage evolution, which is reminiscent of the skin effect. The order and parameters of this differential equation are determined empirically using system identification techniques. Fast plasma current modulation experiments with Random Binary Signals (RBS) have been conducted in the TCV tokamak to generate the required data for the analysis. Plasma current was modulated in Ohmic conditions between 200kA and 300kA with 30ms rise time, several times faster than its time constant L/R≈200ms. A second order linear differential equation for the equilibrium loop voltage is sufficient to describe the plasma current and internal inductance modulation with 70% and 38% fit parameters respectively. The model explains the most salient features of the plasma current transients, such as the inverse correlation between plasma current ramp rates and internal inductance changes, without requiring detailed or explicit information about resistivity profiles. This proves that lumped parameter modeling approach can be used to predict the time evolution of bulk plasma properties such as plasma inductance or current with reasonable accuracy; at least in Ohmic conditions without external heating and current drive sources.

show abstract

Modeling and control of TCV

Cited by 24 publications

References 19 publications

A Variable Structure Control Scheme Proposal for the Tokamak à Configuration Variable

A Variable Structure Control Scheme Proposal for the Tokamak à Configuration Variable

Internal inductance predictive control for Tokamaks

Development and validation of a tokamak skin effect transformer model

Contact Info

Product

Resources

About