Power Supply Control at NSLS-II
Yuke Tian Control Group, NSLS-II, BNL
(May 1, 2009 EPICS Collaboration Meeting, Vancouver)
Outline
1. Power supply control in accelerator
2. NSLS-II power supply control system
3. Synchronism, deterministic and reliability in NSLS-II power supply control
4. Summary
EPICS Collaboration Meeting, Vancouver 2009
Power supply control in accelerator: magnets at NSLS-II
Standards for Main Dipole Magnet Standards for Quardupole Magnet Standards for Sextupole Magnet
SC
FCFC
FC
FC
FC
FC
SC SCSC
SC
SC
SC SCSC
SC
SC
SC
FC Standards for Fast Corrector Magnet SC Standards for Slow Corrector Magnet
Dipole
Dipole
EPICS Collaboration Meeting, Vancouver 2009
Power supply control in accelerator
• Power supply system functions Establish particle orbit Orbit correction Beam-based alignment Tune adjustment Cure of chromaticity Response matrix measurement Power supply analysis
• Power supply system performance requirements and NSLS-II solutions Reliability: power supply causes most of the failure time
1) Failures caused by harsh environments: moisture, dust, temperature etc.
2) Power supply control system failure: communication, IC parts failure etc.
Synchronization: power supply system needs to be synchronous with other accelerator subsystems to perform various functions. Usually the synchronization is done through timing system.
EPICS Collaboration Meeting, Vancouver 2009
NSLS-II solutions: temperature controlled racks.
NSLS-II solutions: redundant SDI links; Built-in diagnostic functions.
NSLS-II solutions: fully synchronous system including BPMs, cell controllers and power supply controllers.
Power Supply Control at NSLS-II: overview
Fast Orbit Feedback Synchronous Bus
Ethernet – EPICS Channel Access Protocol
Events/ / Timing Data
CPU
Cell Controller
FC1
FC2
FC3
SC1
SC2
SC6
Correctors
DCPS 01
DC Power Supply Controllers For Multipole Magnets
RFBPM 1
XRay BPM1
RFBPM 2
RFBPM 8
XRay BPM2
XRay BPM4
DCPS 02
DCPS 39
PS control For one cell
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XRay BPM4
Power Supply Control at NSLS-II: overview
EPICS Collaboration Meeting, Vancouver 2009
NSLS-II Power Supply Control System
NSLS-II Power Supply Control System: Cell Controller
Detailed Structure of Cell Controller
EPICS Collaboration Meeting, Vancouver 2009
NSLS-II Power Supply Control System: PSC, PSI, Regulator
Power Supply Control System
EPICS Collaboration Meeting, Vancouver 2009
NSLS-II Power Supply Control System: PSC
Power Supply Controller (PSC)
EPICS Collaboration Meeting, Vancouver 2009
NSLS-II Power Supply Control System: PSI
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Power Supply Interface (PSI)
NSLS-II Power Supply Control System: Regulator
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Current Regulator Module
Synchronism, Deterministic and Reliability in NSLS-II power supply control
Clock Domains In Accelerators
EPICS Collaboration Meeting, Vancouver 2009
Synchronism, deterministic and reliability in NSLS-II power supply control
• Synchronism in NSLS-II
125MHz clock (in sync with master oscillator) and fiducia will be distributed. We already have a very fine, low jitter clock. We can synchronize all circuit with this RF clock. We can timestamp every event with 8ns resolution. All the systems are talking with the same clock.
Traditional power supply control system receive a trigger pulse from timing system and use local oscillators to drive the DAC, ADC etc.
EPICS Collaboration Meeting, Vancouver 2009
NSLS-II solutions: pushing synchronism to power supply control. The DAC, ADC and FPGA are synchronous with RF main oscillator. The local oscillators are for back up in case the RF main oscillator is not available.
Synchronism, deterministic and reliability in NSLS-II power supply control
Pushing Synchronism to Power Supply Control at NSLS-II
EPICS Collaboration Meeting, Vancouver 2009
Synchronism, deterministic and reliability in NSLS-II power supply control
PS setpoint PS readback PS for fast correctors
Total data for FOFB 100Mbit/s SDI link
2 18-bit DAC8-bit command
(7 bytes/PS)
10 16-bit ADC(20bytes)
6 PS Setpoints: 7x6=42 byteReadback: 20 byte
Assume payload: 42 bytes
42 *7 =294 Byte
(294*8)/100Mb = 24us
Latency of Power Supply SDI Link
EPICS Collaboration Meeting, Vancouver 2009
Summary
EPICS Collaboration Meeting, Vancouver 2009
• At NSLS-II, power supplies and the power supply control systems are designed with goals of high reliability, easy for diagnostics, and easy for integration.
• At NSLS-II, we are design a open source communication interface for power supply control system. It offers more advantages than other communications interface such as RS232, RS485, CAN etc.
• At NSLS-II, we are pushing synchronism to power supply control level. So, all the subsystems (BPM, PS, LLRF etc) are all synchronized, many accelerator applications can benefit from this synchronism. Fast orbit feedback system 1) Synchronous distribution of BPM data (by SDI between cells) 2) Matrix math and regulation (done with the same clock) 3) Corrector PS actions (by SDI between PS controller) Response matrix measurement: 1) Synchronous kick one or more magnets (by SDI between PS controller)
2) Synchronous measurement of the BPM data (by GigE interface) Other applications: tune measurements, synchronous PS ramping etc.
EPICS Collaboration Meeting, Vancouver 2009
Acknowledgement
Wing Louie (BNL)John Ricciardelli (BNL)George Ganetis (BNL)Larry Doolittle (LBNL)
Bob Dalesio (BNL)Carlos Serrano (LBNL)
Thank you !