Output Current Stability Research Articles

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.

An Improved Voltage Control Method for EAST Fast Control Power Supply

The Experimental Advanced Superconducting Tokamak (EAST) fast control power supply (FCPS) is an important device for controlling the vertical displacement of plasma during the nuclear fusion power generation process, adopting a multiple H-bridge invertor branch parallel operation structure to output total current. At the beginning of each shot of plasma discharge, FCPS works in open-loop voltage control mode (VCM) or closed-loop current control mode (CCM) determined by the plasma control system to output current for exciting the load coil, to achieve plasma vertical displacement control. VCM has the characteristics of fast dynamic response speed but poor consistency of branch current and insufficient branch current control accuracy and stability because of open-loop control. CCM has the characteristics of high branch current control accuracy but poor dynamic response and robustness because of control delay and control parameters determined based on engineering experience. To achieve fast and robust control, an improved voltage control method (IVCM) is proposed by combining the advantages of VCM and CCM. In the beginning of establishing the output current, FCPS operates in VCM, and rapid establishment of the output current is ensured. After the output current rapidly increases to the critical value, closed-loop current control is added to VCM to ensure the accuracy of output current control. In closed-loop current control, linear super-twisting sliding mode control is designed to achieve fast and robust control, ensuring good consistency and fast dynamic response performance of each branch current. Simulations and experiments verify that the designed IVCM has better compatibility characteristics in output current stability, control accuracy, and consistency of each branch current compared to VCM.

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.

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.

A fully digital power supply system for TLS corrector magnets

This study focuses on the development of a fully digital power supply system (FDPSS) for the Taiwan Light Source (TLS) storage ring corrector magnet, which includes the fully digital correction power supply (FDCPS), digital communication card (DCC), and a virtual operation interface. The DCPS adopts a full-bridge circuit architecture, with the TI TMS320F28335 digital signal processor (DSP) as the core, combined with an 18-bit high-resolution A/D converter and discrete PID algorithm to achieve closed-loop current control, ensuring a stable output current value of the system. The DCC can control eight DCPS modules through an RS485 protocol with a virtual instrument control interface. This new system can replace the analog signal-modulated Bira MCOR30A power supply system, which has been in operation for 25 years in the TLS storage ring and can be upgraded to an FDPSS. This article aims to discuss the design concepts, hardware implementation, and testing of FDCPS and DCC to demonstrate the advantages of full digital control and to achieve the goal of independently researching and developing the prototype of FDPSS. Ultimately, after long-term testing and verification, the system's output current stability is less than ± 20ppm, indicating that this new system has high-precision and high-stability output current characteristics. In this study, upgrading the TLS storage ring corrector magnet power supply system to full digital control significantly improves output current stability and accuracy.

Study on low rate of change characteristics of saturation output current of 28 nm UTBB FDSOI at 300 °C high-temperature

Partially-depleted silicon-on-insulator (PDSOI) MOSFETs with full dielectric isolation structure are widely used in the high temperature field of 225 °C, but affected by the threshold voltage and carrier mobility, the saturated output current has a rate of change as high as 24.9% at 25 °C–300 °C, which will reduce the working speed and accuracy of the analog circuit. This paper studies the high temperature output current characteristics of ultra-thin body and buried oxide (UTBB) fully-depleted silicon-on-insulator (FDSOI) MOSFETs with the 28 nm low voltage threshold structure. The experimental results show that when the gate voltage of the device is constant, the saturation current change of 28 nm short-channel FDSOI device is 1.93% in the temperature range from 25 °C to 300 °C, which is 12.9 times more stable than that of 0.13 μm PDSOI device, 4.5 times and 8.4 times higher than that of 0.3 μm and 2 μm long-channel FDSOI device. When the gate voltage of the device drifts from the zero-temperature coefficient (ZTC) point by ±10%–±20%, the output current change of the short-channel FDSOI device is still the lowest. It is proved by theory and simulation that the low temperature change rate of the carrier velocity of the short-channel FDSOI device is the main factor affecting the stability of the output current. From the analysis of the saturation current model and the ZTC operating point, reducing the gate operating voltage of the device or increasing the threshold voltage of the device can further improve the stability of the output current at high temperatures. The research in this paper proves that the 28 nm UTBB FDSOI device has good high temperature saturation current stability, which can well meet the output current stability requirements of high temperature analog circuits.

Dynamic Voltage Stability Enhancement in Electric Vehicle Battery Charger Using Particle Swarm Optimization

Electric vehicles (EVs) are poised to lead the transportation sector as the primary choice of automobile due to their efficiency and environmental benefits. EVs with enhanced autonomy and reduced pricing have become feasible in the market, enabling a gradual transition for higher EV penetration. However, electric vehicles require highly efficient and stabilized charging stations in urban areas to ensure the vehicle’s charging time is not compromised. In this regard, the Vienna rectifier with a voltage-oriented controller (VOC) plays a significant role in improving the power quality of the utility grid for EV battery charger applications. The low stability of the battery charger’s output voltage and current is due to the trial-and-error method used to select the PI controller gains. In order to improve the voltage and current stability, the particle swarm optimization (PSO) technique is used to optimize VOC’s PI controller gains. The code composer studio (CCS) platform integrates the PSO technique for EV battery chargers in the experimental setup. The Vienna rectifier with VOC for EV battery charger is implemented using TMS 320F28337 digital signal controller in the test board. Findings indicate that the PSO optimized VOC improves the output voltage and current stability by 12% compared to the existing trial-and-error technique. Furthermore, the proposed system is tested in an experimental setup that provides input current THD to less than 5% for different load variations (up to 1.5kW) to meet the IEEE-519 standards. Results from simulations and experimental setup verify that the proposed PSO-PI controller-based Vienna rectifier significantly improves EV battery chargers’ output voltage and current stability.

A high-power and high-stability power supply design

BEPCII is a high-performance collider with a design energy of 2.1 GeV. In order to obtain more physical experiments and synchrotron radiation applications, BEPCII decided to carry out energy upgrading to 2.5 GeV. Insufficient energy of special magnet power supplies in collision zone is a key factor restricting BEPCII's operation under 2.5 GeV energy. Therefore, three high-power and high-stability power supplies are designed for BEPCII energy upgrading. The designed power supplies output part adopts high-frequency chopper modules parallel connected and adopts digital-analog hybrid control methods. The voltage loop regulator uses high-speed analog control, and current loop regulator uses digital control which is based on FPGA. The experimental data show that the output current stability of the developed power supplies is lower than 50 ppm. The output current resolution is lower than 70 ppm. The developed power supplies can well meet the design requirements of BEPCII energy upgrading.

Power Supplies of Correction Magnets of Modern Accelerating Complexes

The Budker Institute of Nuclear Physics has been designing two accelerator facilities of the MegaScience class [1, 2]. It is planned to use the same bipolar power supplies sources for corrector magnets in both projects. These power supplies must provide an output current of 6 and 12 A and output voltage up to 100 V. Identical power-supply sources will be used both for slow orbit correction and for fast orbit feedback. As a result, the power-supply sources must provide the high stability of output current (at least 0.01%) and adequate bandwidth (at least 1k Hz). The project must allow for the fast replacement of a failed power-supply source.

A precision ADC sampling system design

The high-energy photon source, which has been built in Huairou, Beijing, has high requirements on magnetic field dithering. Magnetic field dithering is mainly determined by the stability of the output current of the power supply. In order to ensure the stability of the output current of quadrupole magnet power supply, the power supply sampling control loop needs to be precisely designed. In this paper, a precision ADC sampling system based on internal temperature control is designed to carry out precise control of the sampling ADC. In this design, precise ADC chip is used to complete the precise sampling of the system. The precise sampling system contains a DAC system for high-speed settings. In order to verify the design of the system, high-precision quadrupole magnet power supply is used for measurement. The experimental results show that the temperature variation range of precision temperature control ADC system is ± 0.1 °C. By using the precise temperature control ADC system, the output current stability of the high-precision quadrupole magnet power supply is effectively improved.

Improvement the Bending Magnet Power Supply Performance for TPS Storage RING

In the TPS (Taiwan Photon Source) facility, current stability of the electron beam depends on the bending magnet power supply and an orbit FOFB system to compensate the magnetic field. Due to the output current stability of the bending magnet power supply drifts with temperature so the orbit FOFB system should be applied to fine tune magnetic field and the photon beam should circulate in storage ring. In this paper, to stabilize the temperature of regulation circuit’s temperature box of the bending magnet power supply, the long-term output current stability is improve from ± 50ppm to ± 10ppm, and orbit FOFB system substantially reduce the tune X of beam position, effectively increasing the beam current stability and quality. In the TPS (Taiwan Photon Source) facility, current stability of the electron beam depends on the bending magnet power supply and an orbit FOFB system to compensate the magnetic field. Due to the output current stability of the bending magnet power supply drifts with temperature so the orbit FOFB system should be applied to fine tune magnetic field and the photon beam should circulate in storage ring. In this paper, to stabilize the temperature of regulation circuit’s temperature box of the bending magnet power supply, the long-term output current stability is improve from ± 50ppm to ± 10ppm, and orbit FOFB system substantially reduce the tune X of beam position, effectively increasing the beam current stability and quality.

Design of driving circuit for chaotic lasers with different thermoelectric coolers

In order to effectively regulate and control the temperature and the driving current of chaotic lasers with different thermoelectric coolers (TECs), we optimize the circuit on the basis of the previous circuit design. The new circuit achieves effective control of the temperature and current of chaotic lasers with different TEC models. The range of the maximum output voltage at the TEC end is from 0 to 3.3 V. The output current stability is controlled within 0.02%, and the output wavelength fluctuation of the laser is stabilized within 9 pm. Compared with the control of the Newport driver, the normalized mean square error of the output wavelength of transmitter optical subassembly (TOSA) laser is decreased from 0.004 4 to 0.002 0. The stability of control has been improved.

The design of the superconducting wiggler power supply system for HEPS-TF

PurposeThis paper describes the design of power supply system for superconducting wiggler in the project of high energy photon source-test facility. It includes three sets of high precision DC stabilized current power supplies for superconducting magnet excitation and three sets of quench protection assembly (QPA). A special magnetic load which has a very large time constant is studied in this paper. In this paper, a stable superconducting excitation power supply is developed, which can adjust the response quickly under the condition of very large load time constant. Meanwhile, the energy dissipation circuit of the QPA is integrated into the power supply in an active quenching protection mode to accelerate the energy release of the superconducting magnet and protect the superconducting magnet.MethodThe main circuit topology, control algorithm, quenching protection circuit and interlocking logic function are designed for the superconducting magnet with large inductance. The upper computer controls the switch of the three main power circuits through the serial port, sets the output current and adjusts the parameters according to the load.ConclusionThrough a series of scientific and rigorous experiments, the rationality of superconducting wiggler magnet power supply scheme is demonstrated. The output current stability test and output voltage ripple test of the power supply meet or exceed the requirements of the magnet system.

The Development of a New Low Field Septum Magnet System for Fast Extraction in Main Ring of J-PARC

The J-PARC Main Ring are working on improved beam power to 750 kW by shortening the repetition period from 2.48 s to 1.3 s. The low-field septum magnets in the fast extraction beam line will be replaced by new magnets around 2020. We constructed a test-bench of a new magnet which are induced eddy current type and a new power supply in 2014. We were in trouble with the periodic radiative noise which had effect on the stability of output current. We tried to protect against the radiative noise, and finally we were able to solve the problem. In March 2018, we introduced a new Sub-charger system instead of the Dropper which broke down in 2016 due to difficulty of its tuning. Since the scheme of the Sub-charger is simpler than that of Dropper, we can expect to operate stably. The stability of output current requires below 100 ppm, and we confirmed the Sub-charger system satisfied that. We measured the horizontal distribution of the field integral of the magnetic gap field, and the flatness was 0.04%/50 mm which is much smaller than that of current low-field septum magnets.

Principle and Design of a Single-Phase Inverter-Based Grounding System for Neutral-to-Ground Voltage Compensation in Distribution Networks

Neutral-to-ground overvoltage may occur in noneffectively grounded power systems because of the distributed parameters asymmetry and resonance between Petersen coil and distributed capacitances. Thus, the constraint of neutral-to-ground voltage is critical for the safety of distribution networks. In this paper, an active grounding system based on a single-phase inverter and its control parameter design method is proposed to achieve this objective. Relationship between its output current and neutral-to-ground voltage is derived to explain the principle of neutral-to-ground voltage compensation. Then, a practical current detection method is proposed to specify the reference of compensated current. A current control method consisting of proportional resonant and proportional integral (PI) with capacitive current feedback is then proposed to guarantee sufficient output current accuracy and stability margin subjecting to large range of load change. The PI method is taken as the comparative method and the performances of both control methods are presented in detail. Experimental results prove the effectiveness and novelty of the proposed grounding system and control method.

2차 델타 시그마 변조기법을 이용한 고 정밀 및 고 안정 디지털 전자석 전원 장치에 관한 연구

This paper is writing about developing magnet power supply. It is very important for power supply to obtain output current in high precision and high stability. As a switching noise and a power noise are the cause of disrupting the stability of output current, to remove these at the front end, low pass filter with 300Hz cutoff frequency is designed and placed. And also to minimize switching noise of the current into magnet and to stop abrupt fluctuations, output filter should be designed, when doing this, we design it by considering load has high value inductance. As power supply demands the stability of less than 5ppm, high precision 24bit(300nV/bit) analog digital converter is needed. As resolving power of 24bit(300nV/bit) analog digital converter is high, it is also very important to design the input stage of analog digital converter. To remove input noise, 4th order low pass filter is composed. Due to the limitation of clock, to minimize quantization error between 15bit DPWM and output of ADC having 24bit resolving power, ∑-? modulation is used and bit contracted DPWM is constituted. And before implementing, to maximize efficiency, simulink is used.

The Fully Digital Controlled Corrector Magnet Power Converter with a Shunt as a Current Sensing Component

In Taiwan light source (TLS), Bira’s MCOR30 power converter modules are adopted as the corrector magnet power converters, the output is regulated by analog PWM IC that caused nonlinear behavior at zero cross and the adjustment of compensator for different kind of magnet load is inconvenient. To fulfill digital regulation control, the analog regulation IC of Bira’s MCOR30 is replaced by a fully digital regulation control circuit. With plugging the homemade fully digital regulation control card into MCOR30 that the current sensing component is a shunt that save cost of the power converter, the switching losses and output current ripple were reduced and stability of output current is improved. With the fully digital regulation control circuit, the parameters of the compensator for different magnet load are very easy to adjust. In addition, the feasibility and validity of MOSFET switching algorism is simulated with MATLAB Simulink and the performance of this power converter is verified, the output current ripple of this power converter could be within 10ppm, which is beyond the requirement of current TLS corrector power converter and qualified to be used in the future TPS facility.

Effect of divalent ion substitution on oxygen sensing properties of hot-spot based Eu1−xCaxBa2Cu3O7−δ and Eu1−yMgyBa2Cu3O7−δ ceramics

In this paper effects of Ca and Mg substitution on oxygen sensing properties of hot spot based Eu123 rods are reported. Eu1−xCaxBa2Cu3O7−δ (x=0.2–0.5) and Eu1−yMgyBa2Cu3O7−δ (y=0.2–0.5) ceramics were synthesized from oxide powders using the standard solid state method and fabricated into short rods. For Ca-substituted rods, after appearance of a visible hot spot, a constant current plateau in I–V curve was formed. The output current response of the rod in periodically changing pO2 between 20% and 100% showed improved stability and reproducibility for x=0.4 compared to x=0.2. Improved oxygen absorption and desorption time was observed for x=0.4 compared to previously reported unsubstituted rod. On the other hand, for Mg-substituted rods the I–V behavior after formation of hot spot showed a negative slope. Faster absorption time of 3.0s and desorption time of 6.9s were observed for y=0.4 compared to y=0.2. The improved output current stability, reproducibility and response time is suggested to be due to changes in oxygen activation energy and increased hole concentration as a result of Ca2+/Mg2+substitutions. The Mg-substituted rods showed better performance compared to Ca-substituted rods possibly due to higher porosity and vacancy concentration.

Design of Hi-Power Continuously Adjustable Constant Current Source Based on UC3846

This paper designs the switch adjustable constant current source based on the current mode PWM control chip UC3846, the power reach to 8kw, current 0~15A continuously adjustable. It uses the I2 control method to ensure the accuracy of the output current stability and improve the dynamic performance and response speed of the system. Feedback signals achieve in external circuit of the chip UC3846, they independent to each other to ensure the accuracy of the control signal. The model of UC3846 and the power supply were built by using Matlab Simulink separately. After building those models, the circuit was simulated by using Simulink, and its simulation results reflected the output of power supply truthfully which played a good guide for the circuit design and experiment, to avoid detours and reduce risk.

Effects of ionic size on oxygen sensing properties of Sr substituted Ho123 ceramic rods utilising hot spot phenomena

The I–V characterisation of Ho(Ba2−xSrx)Cu3O7−δ (x = 0, 0·2 and 0·8) ceramic sensor rod with hot spot in flowing oxygen between 0 and 100% pO2 revealed good oxygen response with output current observed to strongly depend on pO2. All the samples showed higher sensitivity to pO2 below 20% with reduced electrical power consumption in Sr substituted rods. The x = 0·2 rod showed improvement in output current stability, reproducibility and transition of output current response between 20 and 100% pO2 compared to the x = 0 rod. Conductivity was found to be proportional to above 60% for x = 0 rod and above 40% for Sr substituted rods, while lower pO2 conductivity was proportional to , in agreement with the mass action law indicating difference in oxygen ionisation. The results are also discussed in terms of the possible influence of hot spot temperature on the structure of Ho123 and changes in oxygen activation energy as a result of the difference in ionic sizes between Ba2+ and Sr2+.