Magnet Power Supply Research Articles

Recurrent neural networks for anomaly detection in magnet power supplies of particle accelerators

This research illustrates how time-series forecasting employing recurrent neural networks (RNNs) can be used for anomaly detection in particle accelerators—complex machines that accelerate elementary particles to high speeds for various scientific and industrial applications. Our approach utilizes an RNN to predict temperatures of key components of magnet power supplies (PSs), which can number up to thousands in an accelerator. An anomaly is declared when the predicted temperature deviates significantly from observation. Our method can help identify a PS requiring maintenance before it fails and leads to costly downtime of an entire billion-dollar accelerator facility. We demonstrate that the RNN outperforms a reasonably complex physics-based model at predicting the PS temperatures and at anomaly detection. We conclude that for practical applications it can be beneficial to use RNNs instead of increasing the complexity of the physics-based model. We chose the long short-term memory (LSTM) as opposed to other RNN cell structures due to its widespread use in time-series forecasting and its relative simplicity. However, we demonstrate that the LSTM’s precision of predicting PS temperatures is nearly on par with measurement precision, making more complex or custom architectures unnecessary. Lastly, we dedicate a section of this paper to presenting a proof-of-concept for using infrared cameras for spatially-resolved anomaly detection inside power supplies, which will be a subject of future research.

Reduction of Reactive Power Compensation Efforts for Fusion Magnet Power Supplies Using Variable Series Capacitors

Reduction of Reactive Power Compensation Efforts for Fusion Magnet Power Supplies Using Variable Series Capacitors

Research and economic evaluation on novel pulse superconducting magnet power supply topology with energy storage for fusion devices

Large capacity fusion devices power supply poses a significant challenge to the stability of power grid, as it can lead to power outages and jeopardize the safety of fusion devices. And traditional distribution methods result in a significant waste of resources. This paper proposes novel topologies with integrated energy storage. In these topologies, high-amplitude pulsed power is supplied by the energy storage devices, while low-amplitude stable power is obtained from the grid. This decouples the pulsed power from power grid, and significantly reducing its impact. Moreover, it can reduce the design capacity of distribution equipment and lowers investment costs. To optimize the deployment of the energy storage device, a hybrid topology is proposed, which further reducing the cost of the novel power supply. Additionally, a cost model for the fusion power supply is developed and validated using simulation data from ITER. Through the case study shows that the HEPS topology saves more than 10 % of the investment cost and about 60 % of the annual operating cost compared to the traditional converter topology.

Realization of modularized corrector magnet power supply with N+1 redundancy for TPS facilities

This paper delves into implementing multi-module parallel current output using the existing TPS storage ring correction magnet power supply. We have devised a control interface card with N+1 redundancy to facilitate bipolar high-current parallel module output. To achieve this, we have employed various current feedback methods, including external DC Current Transducer (DCCT) and internal module current feedback signals. Following PI compensation, these feedback signals are amalgamated with reference current signals to compute compensation values for each module, which are subsequently disseminated to each Corrector Magnet Power Supply (CMPS) for modulation, thereby enabling closed-loop current control. A single CMPS module can deliver ± 48 V/± 10 A output, while up to eight CMPS modules can be interconnected, yielding a maximum output of ± 80 A. Through numerous experimental measurements, the long-term output current stability remains within 0.6 mA, or 7.5 ppm, with the output current spectrum predominantly maintained within 500 μA. Furthermore, the system boasts N+1 redundancy functionality and bipolar output current characteristics. These exemplary performance attributes underscore the criticality of our design for future applications of TPS magnet power supplies.

Development of a pulsed magnetic field power supply for small size Betatron

In this paper, we present a new structure of capacitor-inductor discharge circuit and develop a pulsed magnetic field power supply for small size Betatron, addressing the urgent need for adjustable pulsed radiation frequencies. The proposed power supply employs insulated gate bipolar transistors (IGBTs) to control the discharge of the energy storage capacitor to the excitation winding, thus generating a pulsed current, which produces a pulsed magnetic field and accelerates the electrons. By adjusting the operating frequency of the IGBTs, the frequency of the pulsed current, and consequently the accelerator pulsed radiation frequency, can be regulated. The proposed design employs dual sustained paths, which are formed by the energy storage capacitor and the excitation winding, as well as a loss-compensation capacitor with the excitation winding. By adjusting the loss-compensation time, the problem of the pulsed current amplitude attenuation due to losses can be overcome, ensuring the stability of the pulsed magnetic field. Experimental results show that the power supply produces a pulsed current up to 220 A, which accelerates the electrons to 6.2 MeV, allowing the accelerator pulsed radiation frequency to be adjusted within a 333-Hz range. The proposed power supply makes small size Betatron suitable for a wide range of applications and provides technical knowledge for other types accelerators.

Investigation and improvement of spill quality at XiPAF synchrotron

The Xi’an 200 MeV Proton Application Facility (XiPAF) is a specialized facility designed to simulate space radiation environments. To meet the requirements of space radiation simulation, the proton accelerator must provide a quasi-continuous spill. The facility has achieved this goal by implementing third-order resonance and RF knockout (RF-KO) slow extraction. In this study, the source of the spill ripple at the XiPAF synchrotron was analyzed and a method was developed to calculate the fluctuation ratio of the spill from the spill spectrum. According to the experimental results, the spill quality at XiPAF is mainly affected by the ripple of the magnet power supply. To improve the spill quality, the frequency spectrum of the excitation signal was optimized to suppress the influence of the power supply ripple. We found that the dual-frequency signal, which consists of the two sinusoidal waves corresponding to the extraction and diffusion regions in the third-order resonance, can significantly reduce the influence of the magnet power supply ripple. After adopting the optimized dual-frequency signal, the fluctuation ratio of the spill is reduced from about 0.15 to 0.092 (sample median) at a sampling frequency of 1.24 kHz.

Integration of monitoring and operation ion source system in the DECY-13 cyclotron

Abstract In nuclear medicine, cyclotrons play a vital role as cyclic accelerators, producing radioisotopes for Positron Emission Tomography (PET) technology. Currently, the Accelerator Technology Research Center, National Research and Innovation Agency of Indonesia, is developing the DECY-13 cyclotron, which comprises several crucial components, including the ion source. The ion source generates ions that is accelerated to a specific energy level before being directed at the target. The ion source system of the DECY-13 cyclotron includes various supporting components, such as a cooling system, vacuum system, Magnet Power Supply (MPS), gas flow system, and cathode power supply. These components are currently operated independently, with manual monitoring by operators. To simplify and improve the operation, an integration project needed for supporting component of the DECY-13 cyclotron’s ion source. This integration utilizes LabVIEW software, the NI-9870 module, NI-9425 module, and NI-cRIO as the process operation controller. The successful development of the integration program ensures that the displayed data on the interface aligns seamlessly with data from each individual device. Consequently, the integration program serves as an effective tool for monitoring the operation of the DECY-13 cyclotron’s ion source.

A novel generation design dipole magnet power supply of booster to storage ring transport line in NSRRC

The Taiwan Light Source (TLS) is a synchrotron radiation facility located in Taiwan. The booster ring at TLS injects electrons into the storage ring, which then circulates the electrons to produce synchrotron radiation for various experiments. The Taiwan Light Source (TLS) has been in service for more than 20 years, and some of the power supplies used in the facility are old and hard to maintain repair and the component are phase-out. The upgrade is specifically aimed at replacing the power supply for the BTS (Booster to Storage ring) transmission line with a new machine. During the regular shunt down time, dipole magnet power supply replacements were completed. The main reason for using the Chroma 62075H-30E power supply is commonality, for this machine is widely used in Taiwan Photon Source (TPS), and the output current of the power supply is paralleled to a dipole magnet. Therefore, a total of 17 power supplies are used in this upgrade planned to be executed. This novel generation upgrade design is important because the power supply for the BTS transmission line is critical for the operation of the facility, as it is responsible for maintaining the electron beam at a stable energy level as it is injected from the booster ring into the storage ring. A more reliable and efficient power supply can help improve the stability and quality of the electron beam, leading to better experimental results and more efficient use of the facility. Overall, this novel generation upgrade design is part of the ongoing effort to modernize and improve the infrastructure of the TLS, ensuring that it remains a state-of-the-art research facility for years to come.

Development of bipolar high-current correction magnet power supply for TPS facility

Taiwan Photon Source (TPS) is a globally renowned 3 GeV synchrotron accelerator light source. With a successful decade of operation, various subsystems have continuously improved and maintained an optimal research facility environment. Presently, there is a concerted effort towards energy conservation. This technical report focuses on the future development of the TPS-II Permanent Magnet Trim Coil Power Supply for the correction magnet, emphasizing a Bipole high-current correction magnet power source. According to the prototype specifications, the maximum output current is 20 A with an operating voltage of 48 V. This augmentation increases the amplitude of the magnetic field correction in the permanent magnet-associated Trim core, providing greater flexibility in manufacturing the permanent magnet correction coils. To design a power supply with high current and stability, the system adopts the Danisense DP50-IP-B DC Current Transducers (DCCT) as the current feedback component and Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) as power switches in a full-bridge (H-bridge) configuration. The driving frequency is set at 40 kHz. Analog modulation control circuitry and protective circuits ensure precise control loop modulation. In the power laboratory, a hardware prototype circuit was constructed, featuring a 48 V input voltage, 20 A output current, a maximum power of 960W, and a current ripple component maintained within 100 μA. This experiment validates the control loop design of the prototype, showcasing the ability to achieve rapid and stable output current performance. Using a 1 V input reference signal for small-signal testing, the bandwidth displayed a -3 dB bandwidth of 8.51 kHz. Long-term current stability is within ± 10 ppm, and interface compatibility with the existing TPS correction magnet power source interface allows direct operation within the current system.

Optimization stability and performance of the TPS storage ring dipole magnet power supply

This article focuses on the current status of the dipole magnet power supply (DMPS) and improvement in the Taiwan Photon Source (TPS) storage ring. The DMPS provides a stable and precise magnetic field for the storage ring operation. Appropriate wiring methods are employed to minimize magnetic field interference across the entire TPS area to meet the demands of high-energy output and overcome the challenges of operating at high currents. The target energy is set at 850 V and 750 A, utilizing a single-pole switching voltage regulator as a high-precision constant current source output structure. The system incorporates a closed control loop that uses the Direct Current Current Transducer (DCCT) to provide current signal feedback to the system. FPGA (Field-Programmable Gate Array) calculates PID (Proportional-Integral-Derivative) compensation values, generating a 2.1 kHz pulse width modulation (PWM) signal to regulate the output current. At the same time, insulated gate bipolar transistor (IGBT) modules are switching components. However, even after several years of practical operation, the stability and performance of the DMPS in the storage ring still require improvements. To enhance long-term output current stability and address peripheral issues, the current TPS utilizes the Beam Orbit Feedback (FOFB) system to suppress and fine-tune the magnetic field and compensate for the impact of temperature drift on the DMPS's output current. This improvement ensures a more stable circulation of the photon beam within the storage ring. By optimizing the temperature control circuit of the main control card, the long-term output current stability has been successfully enhanced to within ± 10 ppm. Simultaneously, the FOFB system reduces uncertainties in adjusting the X-axis beam position, improving beam stability and quality. Furthermore, relevant protective measures have been implemented to ensure robust system operation. Ultimately, these improvement measures have successfully met TPS's stringent requirements for the DMPS, enabling the synchrotron accelerator light source to operate at higher performance levels and fostering advanced scientific research. The results of these upgrades underscore the success of the power supply enhancements, making significant contributions to the overall improvement of the Taiwan Photon Source facility.

Develop an automated data acquisition system for TPS correction magnet power supply

Taiwan Photon Source is a third-generation 3 GeV synchrotron light source. Since the successful operation of the first beamline in 2013, comprehensive long-term testing and acceptance work has been carried out to ensure the stable operation of various types of correction magnet power supplies, totalling 1038 units. To standardise and save workforce and time for the measurement of correction magnet power supplies, an automated data acquisition system platform for correction magnet power supplies was developed using LabVIEW. This platform integrates control interface cards, high-resolution digital voltmeters, and analysis instruments. It also includes linearization and calibration compensation for the multi-channel direct constant current transformer to ensure simultaneous measurement of 24 magnet power supplies. Furthermore, it can automatically generate test reports in Word format, saving significant human resources and time. This platform has verified TPS correction magnet power supplies before installation, reducing the failure rate. Regarding measurement results, the output current ripple for the DCCT version is within five ppm, while the shunt resistor version is within ten ppm. The long-term current stability is consistently within ten ppm. The development of the fully automated data acquisition system platform and the measurement of 1038 power supplies were completed in four months.

Load model of high power magnet power supply for EAST based on GMPSO-BP neural network

To provide an accurate dynamic load model for the stability analysis of Tokamak, a method of back propagation (BP) neural network employing particle swarm optimization(PSO) algorithm based on mutation of Gaussian white noise disturbance (GMPSO-BP) is recommended. This method performs high-precision fitting using the GMPSO-BP neural network on the measured data of the experimental advanced superconducting Tokamak (EAST) poloidal field magnet power supply, extracts network parameters to build a dynamic load model, and then compares the simulation results with the measured data to calculate the error coefficient. The model is a component of the EAST distribution network's digital simulation model. An analogous load model is employed instead of developing the poloidal field magnet power supply from the mechanism. The revised algorithm has quick convergence times, good initial value adaptability, and error function accuracy of 0.3 to 3 %. The simulation outcomes show that the approach has a greater training effect.

Perbandingan Sistem Levitasi Magnetik Ems dan Eds Untuk Maglev Indonesia

Maglev trains are considered for urban transport and intercity transport systems. On low-medium speed Maglev trains, the operating routine is shorter than that of high-speed trains. Therefore, EMS and LIM technologies are preferred from the point of view of construction costs. However, in high-speed operation, EDS and NGO technologies are preferred for handling, and reliability. In addition, as the development of high-temperature superconductors and new types of permanent magnets develop, stronger and more cost-effective magnetic energy will be used for Maglev trains. The authors believe this technology can be utilized not only for railway applications but also aircraft launch systems and spacecraft launch systems. The need for a new and improved transportation system prompted many countries to be interested and seek to develop Maglev railways. However, although Maglev trains have been studied and developed for approximately half a century, few countries have the knowledge and expertise to do so. This review paper attempts to describe the current complete system in detail and summarizes the basic core technologies of Maglev trains from an electrical engineering point of view. The research hopes to be useful for people interested in this to assimilate Maglev train technology including magnetic levitation, propulsion, guidance, and power supply systems.

Analysis of the bi-bridge topology and power device circuit of the TPS booster dipole power supply

This study primarily discusses a unique topology for constructing a double full bridge circuit. The study establishes a push-pull inverter model and analyses the balance circuit in its architecture. This allows the power supply to initiate the balance circuit and ensures the TPS (Taiwan Photon Source) booster magnet power supply operates smoothly in a safe and balanced voltage region when magnet energy is recovered. We employ the approach of adding Y circuits to mitigate the impact of common mode (CM) noise. Adding a Y circuit effectively suppresses the common-mode noise generation, improving the quality of the output current of the TPS dipole magnet power supply at low currents state and ramping the beam current energy from 150 MeV to 3 GeV. Furthermore, the reproducibility and stability of the injection point can enhance the injection efficiency of the TPS booster magnet power supply. This study presents the results obtained from these efforts.

Simulation study on the slow extraction for the improvement of the beam shill structure at J-PARC Main Ring

J-PARC Main Ring (MR) delivers a slow extracted 30 GeV proton beam to the Hadron Experimental Facility using third-order resonance. One of the critical properties required for the proton beam is the flatness of the time structure of the extracted beam (spill structure). We performed a simple beam simulation of the MR slow beam extraction to investigate the effect of the current ripples of the main magnet power supplies on the beam spill structure. In addition, we investigated in the simulation the effects of the feedback control system on the betatron tune using fast Q magnets and the transverse RF system to improve the spill structure. The simulation qualitatively reproduced the measured spill structures. Now the attempts to optimize their parameters for better spill structure are ongoing.

Stability and Reliability Analysis of High-Power Magnet Power Supply Based on Long Pulse Operation of CRAFT

Stability and Reliability Analysis of High-Power Magnet Power Supply Based on Long Pulse Operation of CRAFT

High-Power Modular GaN Based Power Supply for MedAustron Scanning Magnets

MedAustron is a synchrotron-based ion therapy center in Wiener Neustadt, Austria, constantly working towards the performance improvement of cancer treatment. A major improvement opportunity comes from the scanning magnets system – a crucial element of dose delivery system at MedAustron - that is influenced by the bandwidth and power density of the magnet power supplies. Therefore, a novel highly modular power converter, based on the latest gallium nitride technology is being developed to tackle the aforementioned requirements. One sub-module of this power supply is based on two H-bridges that are operated in hard parallel and are integrated into a standardized euro-crate form factor with target output power specifications of 720 kW. This design also includes a 4th-order output Bessel filter to meet the ripple requirements for clinical operation. Furthermore, those sub-modules offer the possibility of being connected, cascaded or interleaved, in order to meet different output power requirements, providing a high modularity aspect. The status of this development in terms of requirements, global topology, and control structure is presented.

Development of linear power operational amplifier power supply with pre-regulated voltage controller for TPS correction magnets

The Taiwan Photon Source (TPS) is a renowned 3 GeV synchrotron accelerator light source. Over the past decade of successful operation, it has demonstrated outstanding performance, notably in average beam trip downtime, meeting international standards. A continuous regimen of scheduled equipment upgrades has been maintained across all subsystems to ensure ongoing improvement and the preservation of an optimal research facility environment. The central focus of this study revolves around the design and realization of a TPS correction magnet power supply employing Linear Power Operational Amplifiers (LPOA) in conjunction with a pre-regulated voltage controller. The power source predominantly features APEX Corporation's PA05 LPOA, characterized by bipolar output, high internal power dissipation, and wide bandwidth. Additionally, a DC Current Transducer (DCCT) was employed as the current feedback element, integrated with the pre-regulator voltage controller to form a closed-loop current modulation circuit, providing the variable voltage required by the LPOA. Through these measures, we have successfully developed an LPOA power supply unit equipped with a pre-regulated voltage controller for TPS correction magnets. The prototype device boasts a maximum output current of ±10 A, operating at 24 V. Validation through control loop design has led to rapid and stable output current performance. The output current ripple is maintained within 100 μA, with a rise time of 75 μs during step response. During frequency response testing utilizing a 0.1 V disturbance signal, the gain margin resides within -3 dB at an 11.2 kHz bandwidth and the phase margin within -45∘ at a 5.1 kHz range. Long-term output current stability is sustained within ten ppm. Finally, a hardware prototype circuit has been constructed in the power supply laboratory, featuring a ±24 V input voltage and ±10 A output current, achieving a maximum rated power of 240 W.

Protection method of traction power supply system for low and medium speed Maglev traffic based on fault traveling wave features

AbstractLow and medium speed magnetic levitation traffic with short power supply distance and complex grounding network structure, prone to power supply rail grounding faults. However, the existing fault location methods do not accurately locate the fault point, making it difficult for the protective device to act to cut off the fault. To address the above problems, this paper builds a dynamic simulation model of the low and medium speed magnetic levitation power supply rails to study the distribution characteristics of the fault traveling waves after a ground fault occurs in the power supply rails, and analyses the generation mechanism of the traveling wave spectrum through formula calculation. First, the difference in current between the positive and negative bus bars is analyzed to determine whether a ground fault has occurred. Second, the direction of the current difference between stations is compared to locate the faulty section. Finally, the fault distance is calculated from the frequency difference of the fault voltage at the double‐ended station. Through simulation, the method is validated to be unaffected by fault location, fault transition resistance, noise interference, and is applicable to short circuit faults caused by lightning strikes, and the ranging error always remains within 20 m. The method has strong robustness, can effectively solve the problem of protection misoperation and accurately locate the fault point. It is suitable for low and medium speed magnetic levitation transportation power supply rail ground fault.

Development of DSP-based TPS fully digital correction magnet power supply

The Taiwan Photon Source (TPS) is a third-generation 3 GeV synchrotron accelerator light source. After successfully operating for ten years since its first light in 2013, various subsystems are undergoing updates. In the context of magnet power supply upgrades, the trend toward digitization and high-precision modulation control is driving advancements worldwide. This study focuses on developing a fully digital correction magnet power supply (FDCMPS) based on a digital signal processor (DSP). The prototype utilizes a low-power, floating-point DSP with multiple communication functionalities as the core control unit. The output current is converted into digital values using current sensors and high-precision analog-to-digital converters. Discrete PI compensator algorithms are implemented within the DSP to generate pulse-width modulation (PWM) waveforms, driving a full-bridge (H-bridge) converter configuration with metal-oxide-semiconductor field-effect transistors (MOSFET). This forms a complete, fully digital closed-loop current control system. A virtual control interface is designed to operate the FDCMPS state. The control loop design of the prototype has been validated and demonstrates stable output bipolar current performance. When tested with a 0.1 V input reference signal, the prototype achieves a -3 dB bandwidth of 2.03 kHz. Finally, a hardware prototype circuit was constructed in the power supply laboratory, with an input voltage of 48 V, an output current of 10 A, and a maximum power of 400 W. Overall, the developed fully digital correction magnet power supply prototype showcases stable and high-performance output bipolar current performance. The system achieves total harmonic distortion of output current ripple within 0.3 mA peak to peak and long-term stability within ± 15 ppm. The successful implementation of the prototype establishes a solid foundation for advancing magnet power supply technology at the TPS.