PCaPAC2012 - List of Keywords (simulation)

Paper	Title	Other Keywords	Page
WEPD43	A New Scheme for Direct Estimation of PID Controller Parameters	controls, damping, induction	76
	S. Srivastava, V.S. Pandit VECC, Kolkata, India
	This paper presents a novel scheme for the direct estimation of a PID controller parameters(Kp, TI, Td).The proposal discussed here is only applicable to first and second order stable systems. The formulation begins with system parameter identification (Transfer function of the process), which was calculated by applying weighted-recursive least square method. The pole zero cancellation technique was applied to estimate PID controller parameters ;which in-turn results into the matched coefficients of the system parameters to the Controller parameters. An additional tuning parameters 'α' is proposed in our method, which provides an additional flexibility of tuning the response time of the controller without disturbing the controller parameters. The proposed scheme was bench marked using real time cases of DC Motor speed control and Cruise Control. The effectiveness and robustness of the proposed auto tuning algorithm is verified by the simulation results.
	Poster WEPD43 [0.189 MB]

THPD35	Modeling and Simulation of Indus-2 RF Feedback Control System	cavity, feedback, controls, LLRF	208
	D. Sharma, P.S. Bagduwal, P.R. Hannurkar, M. Lad, N. Tiwari RRCAT, Indore (M.P.), India
	Funding: RRCAT, Indore, Department of Atomic Energy, Government of India The Indus-2 synchrotron radiation source has four RF stations along with their feedback control systems. For higher beam energy and current operation, amplitude and phase feedback control systems of Indus-2 are being upgraded. To understand the behavior of amplitude and phase control loop under different operating conditions, modeling and simulation of RF feedback control system is done. RF cavity base band quadrature domain model has been created due to its close correspondence with actual implementation and better computational efficiency which make the simulation faster. Correspondence between base band and actual RF cavity model is confirmed by comparing their simulation results. Base band Cavity model was studied under different operating conditions. LLRF feed back control system simulation is done using the same cavity model. Error signals are intentionally generated and response of the closed loops system is observed. With implementation of feedback control loop, broadening in the RF cavity bandwidth was also observed in terms of reduction in cavity fill time. Simulation will help us in optimizing parameters of upgraded LLRF system for higher beam energy and current operation.
	Poster THPD35 [0.698 MB]

THPD46	Simulation Analysis of Analog IQ based LLRF Control of RF Cavity	cavity, controls, LLRF, rfq	225
	S. Basak, A. Chakrabarti, H.K. Pandey VECC, Kolkata, India
	This paper presents the simulation analysis and results in Matlab Simulink of the analog Inphase-Quadrature (IQ) based LLRF control of RF cavity voltage. The RF cavity parameters were selected to be one of the RF cavities in our RIB project. All the subsystems in the IQ based RF control were modeled using the Simulink blocks/components. The envelope simulation was carried out using the IQ model of RF cavity. The PI controller was properly tuned to achieve good control performance in time. The simulation graphs showing the time evolution of the RF cavity voltage with a step changes of the input reference signal is presented. The simulation graphs showing the control response time needed to correct a disturbance is presented. Further the effects of beam currents (if not ignored) on the cavity voltage can been studied through the simulation graphs. The simulation results showing the amplitude and phase Bode/Nichols plots of the control loop and the gain and phase margin values obtained from them are presented, which are good enough for stability. Thus the control simulation RF cavity voltage is done in Simulink and the results obtained are presented.
	Poster THPD46 [0.222 MB]

THPD50	FPGA Based Amplitude Control System for Accelerating Cavities	cavity, controls, pick-up, low-level-rf	239
	M.S. Dey, S. Ghosh, A. Mandal, S. Seth, A. Singh, S.S. Som VECC, Kolkata, India
	The FPGA (Field Programmable Gate Array) based digital controller has been implemented for Low level RF voltage control of a 650 MHz cavity. The flexibility of implementing any appropriate control strategy and to have a compact single board solution, FPGA is chosen. The superconducting Cavity is designed to be operated at 650 MHz and 30 kW, CW mode. The voltage from pick-up coil has been fed to the controller after down conversion. The signal is digitized using high speed ADCs. The controller has been tested with different set points and gain parameters from a software connected to the board with serial interface. The FPGA signal processing has been verified according to the required strategy of the reference controller. Some experimental results have been presented for different cavity operational conditions.
	Poster THPD50 [0.613 MB]

FRCD02	Process Control for Parallel Run of Two Helium Liquefiers at VEC Centre, Kolkata	controls, cyclotron, cryogenics, superconducting-magnet	285
	S. Pal, U. Panda VECC, Kolkata, India R. Basak WBSEDCL, India
	Two helium liquefiers are working in tandem while one is always connected with the superconducting cyclotron. High pressure (HP) and low pressure (LP) controls are necessary to maintain varying helium flow to the cold box. Since these two liquefiers share the same HP and LP pipelines, any pressure fluctuation due to rapid change in flow sometimes causes trip to the liquefiers. To overcome this problem there is a need for fast responsive HP control. Introduction of derivative gain in the PID loop for fast action is not desirable as it creates instability to the control system. This problem was rectified by introducing a novel control scheme based on the forced opening of the unloading valve to push back helium gas to buffer tank by changing the offset of PI control as a function of Buffer Tank pressure. A simulation using Matlab Simulink was performed initially to check the performance of pressure control loop. The same is implemented in the control loop of the new liquefier and an experiment was performed. The experimental results obtained will be discussed in the final paper.
	Slides FRCD02 [1.375 MB]

Paper

Title

Other Keywords

Page

WEPD43

A New Scheme for Direct Estimation of PID Controller Parameters

controls, damping, induction

76

S. Srivastava, V.S. Pandit
VECC, Kolkata, India

This paper presents a novel scheme for the direct estimation of a PID controller parameters(Kp, TI, Td).The proposal discussed here is only applicable to first and second order stable systems. The formulation begins with system parameter identification (Transfer function of the process), which was calculated by applying weighted-recursive least square method. The pole zero cancellation technique was applied to estimate PID controller parameters ;which in-turn results into the matched coefficients of the system parameters to the Controller parameters. An additional tuning parameters 'α' is proposed in our method, which provides an additional flexibility of tuning the response time of the controller without disturbing the controller parameters. The proposed scheme was bench marked using real time cases of DC Motor speed control and Cruise Control. The effectiveness and robustness of the proposed auto tuning algorithm is verified by the simulation results.

Poster WEPD43 [0.189 MB]

THPD35

Modeling and Simulation of Indus-2 RF Feedback Control System

cavity, feedback, controls, LLRF

208

D. Sharma, P.S. Bagduwal, P.R. Hannurkar, M. Lad, N. Tiwari
RRCAT, Indore (M.P.), India

Funding: RRCAT, Indore, Department of Atomic Energy, Government of India
The Indus-2 synchrotron radiation source has four RF stations along with their feedback control systems. For higher beam energy and current operation, amplitude and phase feedback control systems of Indus-2 are being upgraded. To understand the behavior of amplitude and phase control loop under different operating conditions, modeling and simulation of RF feedback control system is done. RF cavity base band quadrature domain model has been created due to its close correspondence with actual implementation and better computational efficiency which make the simulation faster. Correspondence between base band and actual RF cavity model is confirmed by comparing their simulation results. Base band Cavity model was studied under different operating conditions. LLRF feed back control system simulation is done using the same cavity model. Error signals are intentionally generated and response of the closed loops system is observed. With implementation of feedback control loop, broadening in the RF cavity bandwidth was also observed in terms of reduction in cavity fill time. Simulation will help us in optimizing parameters of upgraded LLRF system for higher beam energy and current operation.

Poster THPD35 [0.698 MB]

THPD46

Simulation Analysis of Analog IQ based LLRF Control of RF Cavity

cavity, controls, LLRF, rfq

225

S. Basak, A. Chakrabarti, H.K. Pandey
VECC, Kolkata, India

This paper presents the simulation analysis and results in Matlab Simulink of the analog Inphase-Quadrature (IQ) based LLRF control of RF cavity voltage. The RF cavity parameters were selected to be one of the RF cavities in our RIB project. All the subsystems in the IQ based RF control were modeled using the Simulink blocks/components. The envelope simulation was carried out using the IQ model of RF cavity. The PI controller was properly tuned to achieve good control performance in time. The simulation graphs showing the time evolution of the RF cavity voltage with a step changes of the input reference signal is presented. The simulation graphs showing the control response time needed to correct a disturbance is presented. Further the effects of beam currents (if not ignored) on the cavity voltage can been studied through the simulation graphs. The simulation results showing the amplitude and phase Bode/Nichols plots of the control loop and the gain and phase margin values obtained from them are presented, which are good enough for stability. Thus the control simulation RF cavity voltage is done in Simulink and the results obtained are presented.

Poster THPD46 [0.222 MB]

THPD50

FPGA Based Amplitude Control System for Accelerating Cavities

cavity, controls, pick-up, low-level-rf

239

M.S. Dey, S. Ghosh, A. Mandal, S. Seth, A. Singh, S.S. Som
VECC, Kolkata, India

The FPGA (Field Programmable Gate Array) based digital controller has been implemented for Low level RF voltage control of a 650 MHz cavity. The flexibility of implementing any appropriate control strategy and to have a compact single board solution, FPGA is chosen. The superconducting Cavity is designed to be operated at 650 MHz and 30 kW, CW mode. The voltage from pick-up coil has been fed to the controller after down conversion. The signal is digitized using high speed ADCs. The controller has been tested with different set points and gain parameters from a software connected to the board with serial interface. The FPGA signal processing has been verified according to the required strategy of the reference controller. Some experimental results have been presented for different cavity operational conditions.

Poster THPD50 [0.613 MB]

FRCD02

Process Control for Parallel Run of Two Helium Liquefiers at VEC Centre, Kolkata

controls, cyclotron, cryogenics, superconducting-magnet

285

S. Pal, U. Panda
VECC, Kolkata, India
R. Basak
WBSEDCL, India

Two helium liquefiers are working in tandem while one is always connected with the superconducting cyclotron. High pressure (HP) and low pressure (LP) controls are necessary to maintain varying helium flow to the cold box. Since these two liquefiers share the same HP and LP pipelines, any pressure fluctuation due to rapid change in flow sometimes causes trip to the liquefiers. To overcome this problem there is a need for fast responsive HP control. Introduction of derivative gain in the PID loop for fast action is not desirable as it creates instability to the control system. This problem was rectified by introducing a novel control scheme based on the forced opening of the unloading valve to push back helium gas to buffer tank by changing the offset of PI control as a function of Buffer Tank pressure. A simulation using Matlab Simulink was performed initially to check the performance of pressure control loop. The same is implemented in the control loop of the new liquefier and an experiment was performed. The experimental results obtained will be discussed in the final paper.

Slides FRCD02 [1.375 MB]