Converter Power Supply Research Articles

Intrinsically safe DAB converter for reliable power supply in harsh environment via extended phase shift pulse train control

AbstractIn this article, an extended‐phase‐shift‐based pulse train control (EPS‐PT) for an intrinsically safe dual active bridge (DAB) converter is proposed to satisfy the safe and reliable power supply in harsh environments such as gas stations, chemical plants, and mining tunnels in complex power systems. A discrete pulse switching control method is introduced, and the input voltage and output current are sampled to calculate the primary target phase shift angle of the DAB converter, followed by the inner phase shift angle, while the secondary phase shift angle is rapidly adjusted by the voltage feedback. In order to meet the requirements of effective control and safe power supply in harsh environments, the system parameters are designed by comprehensively considering the control performance and intrinsically safe requirements. The simulation and experimental results demonstrate that the proposed DAB converter exhibits rapid dynamic response and intrinsic operation safety.

Power factor preregulation in power supplies using modified single stage non-isolated interleaved Sepic converter with minimal part count

This paper pontificates on design and realization of low-cost single phase single stage modified interleaved Sepic (MILS) converter for power supplies. On contrary to the classical Sepic power converters, the introduced active power factor correction (APFC) converter involves simple idea of paralleling that enables low input and output ripples with minimal device count. The interleaving conceptualization also lessens current stresses and static losses. Also, this modified power processing converter reveals natural power factor correction (PFC) and zero current switching (ZCS) features by discontinuous conduction mode (DCM) operation. Furthermore, the practical corroboration of the proposed converter is built and tested for 250 W hardware model to affirm benefits with 92 % efficiency and their relevant outcomes are reported in this scope. Finally, the power quality (PQ) attributes like, input power factor (PF), total harmonic distortion (THD) over input current under stable and transient cases are disclosed to prove bettered PQ limits at the AC mains as prescribed by various IEEE-519 and IEC 61,000–3-2 standards.

Power converters analyzed in energy storage systems to enhance the performance of the smart grid application

This paper implements and compares the existing power supply converters for an energy storage system to determine the best suited for the smart grid application. A survey of different DC-DC converters is carried out to analyze the battery's overall performance. The main objective is to identify this application's most appropriate energy storage device. The advantages of this technology have high efficiency and reliability, which can connect various energy sources and reduce conduction losses in the power converters. Through the converter control, reference currents are imposed to charge the battery. The battery nominal voltage needs to change to see which type of converter is the most suitable and robust. Simulation results show that the operating ranges of boost-buck, buck-boost, and buck-boost converters with negative output voltage enhance the efficiency of battery and renewable energy sources and compared the DC converters to know the functional voltage for the energy storage system. The power converter's efficiency and control facility will allow us to link the energy storage system with the power grid. The overall installation is established using MATLAB/Simulink software.

Multi-granularity short circuit fault diagnosis for tokamak power converters under small sample conditions and noise interference

The power supply system of a tokamak device is a crucial subsystem responsible for providing the magnetic field for plasma confinement. The timely application of fault diagnosis techniques to identify abnormal states of the power supply is of crucial importance for the safe and efficient operation of tokamak devices. Intelligent diagnostic methods based on Convolutional Neural Networks (CNN) are widely employed nowadays. However, within the operational environment of the device, there exist multiple physical field couplings, and inevitable noise will impact the data. Moreover, the measurement equipment exhibits instability, resulting in limited availability of data that meets the required criteria. To address these issues, this paper investigates a fault diagnosis approach utilizing an Auxiliary Classifier Generative Adversarial Network (ACGAN) for data augmentation, and proposes a Multi-Granularity Denoising CNN (MGDCNN) that accounts for noise interference, enabling diagnosis of faults at different granularities. In our approach, we first construct a multi-granularity structure of the data based on prior knowledge. Then, a hierarchical structure corresponding to the multi-granularity data and robust to noise is built by introducing an embedded Discrete Wavelet Transform (DWT) into the one-dimensional (1-D) CNN. Finally, the natural stratification of the network is combined with individual granularity branches for fault diagnosis. Experimental results on simulated datasets and public benchmark datasets demonstrate that the proposed model achieves a diagnostic accuracy of 98.81 % for short-circuit faults in power supply converter at the finest granularity. Even with noisy data, the model maintains a diagnostic accuracy of approximately 97 %, indicating superior noise resistance performance in the inference process of the MGDCNN network.

Hybrid MGWO- CSO optimized high gain Relift Luo converter for PV based grid tied PMBLDC drive system

Permanent Magnet Brushless Direct Current (PMBLDC) motor has become one of the most important motors in high performance drive systems, for industrial uses especially for electric vehicle (EV) applications to minimize their torque and current ripples. This work proposes a PV based high gain DC-DC converter for uninterruptible constant power supply to the PMBLDC drive application. PMBLDC drive with Hall Effect sensorsis used to make the variable speed operation due to its controllability. In this work, a Relift Luo converter is utilized because of its negligible ripple in output DC voltage, high voltage gain and reduced switching losses. To regulate this converter, PI controller is implemented and to tune the parameters of the controller, Hybrid Crow Search -Modified Grey Wolf Optimization (MGWO-CSO) techniqueis implemented. The surplus energy from PV is transferred to grid through Single phase Voltage Source Inverter (1 φVSI) after generatingadequate power to PMBLDC motor. When there is no power in Photovoltaic (PV)cell during night time, stored energy in grid gives supply to the PMBLDC motor. The motor is effectively controlled by the PI controller along with the hysteresis controller. Furthermore, the developed work is executed in MATLAB/Simulink to foreshow its effectiveness. As a consequence, the proposed work accomplished low THD value of 1.34, high efficiency of 98.2% with reduced switching lossescompared to the conventional techniques.

Operation of Dual-T-Type Modular Multilevel Converter for Uninterrupted Power Supply Under Bridge Failures

Dual-T-type modular multilevel converter (DTMMC) is an alternative for existing uninterrupted power supply (UPS) due to its advantage in flexible leg reusing, multiple power ports and high operating efficiency. In this paper, a DTMMC-UPS which has series configurations on both input/output AC sides obtain high voltage grid/ load accessing interfaces is presented. In the described system, the fact that copies of T-type legs are employed makes the semiconductor failure common to happen. Moreover, both the coupling between rectifier and inverter conversions, and the confliction between inter-cell and inner-cell voltage balancing make the fault-tolerant control a tough issue. In this paper, the switch fault types are firstly clarified and diagnosed by the different impacts on the normal operating. An improved voltage vector modulation is then deduced to facilitate the planning of proper primary switching patterns, to achieve rectifier side normal operation. The secondary alternated LS-PWM is also modified to achieve inverter side normal operation. The experiment results are supplied to verify the validity of the modulation coordinated fault toleration strategy.

Static Characteristics of Magnetic Modulation DC Converters with Analog Filter

The paper examines the most important requirements for current converters, the features of magnetic modulation converters, and identifies their fundamental and design features. The paper considers the principle of constructing converters for contactless DC measurement and their disadvantages of converters, methods of current measurement using magnetic modulation current converters, in which the magnetic permeability of a core made of ferromagnetic material is modulated. The influence of the parameters of the elements of a magnetic modulation current converter with an analog filter on their static characteristics and the influence of modulation on the static characteristics of the sensor have been determined. It has been revealed that the discrete operation of the magneto-modulation DC converter does not affect its static characteristics and the nonlinearity due to the type of modulation also does not affect the static characteristics of the sensor. The most important requirement for the operation of a magneto-modulation DC converter for autonomous power supplies with recharging buffer batteries is the formation of a static characteristic with the specified properties: linearity, sensitivity and the required range of operating currents. An analytical expression for the static characteristic is obtained in the form of the dependence of the output voltage on the values of T1 and T2 for the basic version of a magnetic modulation DC converter with an analog low-pass filter. Curves of the static characteristics of the magneto-modulation DC converter have been constructed for different values of the resistance of the ballast resistor R, as well as curves of the static characteristics of the magneto-modulation DC converter for different values of the supply voltage E. Analytical expressions for the static characteristics of a magneto-modulation DC converter based on magnetic transistor multivibrators with pulse-width modulation, curves of their characteristics and the output voltage of a magnetic modulation DC converter with a digital output and a discrete filter have been obtained.

Cooperation of the Plasma Reactor with a Converter Power Supply Equipped with a Transformer with Special Design

Plasma generation by means of electrical discharge requires specialized power supply systems. The applicability of plasma for various plasma processes depends on its parameters, and these, in turn, depend on the parameters of power supply systems. Arc plasma can be unstable, generating a lot of electromagnetic interference, overvoltage and overcurrent. The power system of a plasma reactor must guarantee good plasma control characteristics, be immune to disturbances and ensure good cooperation with the power grid. This article analyzes the cooperation of a three-phase plasma reactor, with a gliding arc discharge and a power supply system of a new type. This system integrates an AC/DC/AC converter and a five-column transformer with a special design in a single device. Using the properties of magnetic circuits, it is possible to integrate the functions of ignition and sustaining the burning of the discharge in the reactor in a single transformer. The proper design of the transformer is crucial to achieve the good cooperation of the AC/DC/AC converter with both the plasma reactor and the power supply network. The presented power supply design shows a number of positive features, predisposing it to powering arc plasma reactors.

Power quality assessment of a wave energy converter using energy storage

Wave energy has been an immense area of interest in research and industry in our move towards a sustainable energy production society due to its high energy density and surface area. However, the grid connection of wave energy converters is still one of the major challenges due to the complexity of varying wave resources (amplitude and frequency). Wave energy converters grid integration can lead to several potential challenges, such as voltage fluctuations, harmonics and flicker. Using an energy storage system can help to mitigate few challenges by balancing the grid demand with the wave energy converter power supply. Hence, improving the power quality. This study assesses the power quality of wave energy converters equipped with energy storage against the scenario without any energy storage at different power levels. The power quality in this paper is investigated using total harmonic distortion (THD) of the grid current, dc-link voltage ripple and battery current ripple. The study shows that the addition of a hybrid energy storage system lowers the grid current THD at the point of common coupling (PCC), stabilizes the dc-link voltage ripple and reduces the stress of the battery.

Strategies for Real-Time Simulation of Central Solenoid ITER Power Supply Digital Twin

The International Thermonuclear Experimental Reactor (ITER) is a cutting-edge project that aims to develop a sustainable energy source by harnessing the power of nuclear fusion. One of the key challenges in the development of the ITER is the complex electrical grid that is required to support its operations. To address this challenge, a digital twin (DT) of the Central Solenoid (CS) Converter Power Supply grid has to be developed, and real-time simulation strategies have been proposed to monitor and study the performance of the ITER grid. Real-time simulation strategies allow for continuous feedback on the performance of the grid, enabling the quick identification and resolution of issues. However, it is not always possible to perform real-time simulation easily in a real-time simulator; therefore, specific strategies have to be implemented in the DT. This paper focuses on decoupling lines and explicit partitioning as solutions to allow the real-time simulation of the CS Converter Power Supply grid with two converter units (CUs), as required by the ITER Organization (IO). As will be shown later in this article, the proposed approach is progressive and applicable to a more complex grid with multiple CUs. The results concerning the proposed strategies will be analyzed and discussed in terms of real-time performance.

Economic optimization of hybrid renewable energy systems supplying electrical and thermal loads of a tourist building in different climates

Due to the high potential of tourism in Iran and the high utilization of tourist buildings in Iran, as well as the high energy consumption in the buildings sector, this study aims to provide a feasible model for designing a renewable energy supply system for a tourist building in different climates of Iran. According to the country’s climate, 5 cities of Ahvaz, Bandar Abbas, Rasht, Mashhad, and Yazd were selected as the cities under study. The hybrid system also consists of photovoltaic panels, wind turbine, battery, and converter for power supply and boilers with natural gas fuel and geothermal heat pump to provide building thermal load. The heat pump is used to supply the load needed to preheat the building’s hot water. The system is connected to the electricity grid, so by selling excess electricity, the net project costs (NPC) will be reduced and the system can provide part of its need from the grid. The scenarios which were studied are of two categories. In the first category, all the thermal load is supplied by the boiler. After selecting the best economic scenario by Homer software in this category, the heat pump is added to the system by calculating the thermal load required to preheat the hot water. The scenarios used two types of wind turbines with a capacity of 10 and 50 kW and two types of 25-W panels with different efficiencies of 15.3% and 18%. Finally, a top-down scenario was chosen for each city. The best city to run the project on economic criteria is Mashhad with an NPC of $ 195,745 and a renewable fraction of $ 50.5. Using a heat pump to preheat the hot water, would also save 7% on fuel consumption and reduce CO2 production by 639,000 kg per year.

Sliding mode control for pulsed load power supply converters in DC shipboard microgrids

Pulsed power load (PPL) is a special load type in shipboard microgrids (SMGs), which consists of the generation module, energy storage system, and various types of loads. Having a reliable power supply to shipboard loads is a challenge as the SMG operates in islanded mode in most cases. Particularly, the PPLs require high transient power transfer with fast dynamics and strong robustness. Conventional solution to supply for the PPL is based on proportional-integral (PI) control, which can be used by linearizing the system around the equilibrium operation point. However, for a pulsed power supply (PPS) system, the load demand drastically changes in a short time, usually in millisecond level, making the operating point changes when the pulsed power is triggered or terminated. To supply the PPL with fast dynamics and robustness, an improved PPS control method is presented in this paper. By adopting a nonlinear sliding mode control (SMC) method, fast voltage regulation and robust pulse power tracking can be achieved. In the PPS, the PPL power demand is divided into two terms: one is the average power that is supplied by the SMG and the other is the fast pulsed power that is supplied by the storage capacitor. The size and cost of the storage capacitor are reduced as it is intentionally driven to a deep discharge. The PPS system configuration and coordination principle, SMC controllers, and sizing of passive elements in the PPS are analyzed in detail. The effectiveness of the presented PPS is verified by simulation results.

Improved Branch Energy Balance Control for Three-Phase to Single-Phase Modular Multilevel Converter for Railway Traction Power Supply

Maintaining the branch energy balance poses a huge challenge to controller design of many modular multilevel converter (MMC) topologies. Aiming at railway traction power supply system application of a three-phase to single-phase MMC with equal input and output frequency, this article proposes a branch energy balance control with an improved common-mode voltage selection. As a result, the capacitor voltage oscillations as well as circulating currents are reduced greatly. As the MMC is a complicated periodic time-varying system, an average theory is used to simplify the analysis and controller design. The controllability analysis of the system is carried out and the results show that the proposed branch energy balance control is controllable under most load conditions. In addition, the stability of the branch energy balance system is validated through frequency response. Finally, experimental results verify the effectiveness of the control scheme by an 18-cell model based on the RT-LAB platform.

Loss analysis of high-speed permanent magnet motor based on energy saving and emission reduction

In recent years, with the increasing consumption of resources around the world, motors in various industries are also urgently added to the ranks of energy saving and emission reduction. High-speed permanent magnet air compressor is widely used in various new energy vehicles. The study on its loss can provide reference for motor manufacturing industry. In this paper, the 27 kW, 90000 r/min high-speed permanent magnet air compressor is studied and analyzed. Taking 0.1 mm thick silicon steel sheet as an example, two different kinds of silicon steel sheet materials were compared and analyzed through the study of stator core loss. At the beginning of the design of the motor, the material was tested, and the good performance, low carbon and environmentally friendly material was used in the design and manufacture of the motor, which played a good role in the stable operation of energy saving and emission reduction and the motor. The high-speed motor uses frequency converter for power supply, and its characteristics of large harmonic content and high frequency lead to the increase of rotor eddy current loss. Therefore, the analytical calculation method of rotor eddy current loss is derived. This method establishes the physical model in polar coordinate system, and considers the sub domains such as air gap, sheath and permanent magnet. A prototype and an experimental platform were made to study the influence of harmonics on the motor. In this paper, the actual output current harmonics with IGBT and SIC as controllers are studied by comparative method. The actual output current is collected and applied as excitation to the 2D finite element model of motor for analysis and calculation. Finally, the influence of motor loss is analyzed comprehensively, which has reference value for each motor manufacturing enterprise.

Installation Design and Integration of Poloidal Field Converter Units for ITER

The poloidal field (PF) converter units (CUs) with the four-quadrant operation and circulating current capability is to supply power to International Thermonuclear Experimental Reactor (ITER) superconducting magnets. To ensure PF converter system safety and reliability for the operation, the safety distance of transformer installation calculated and studied. The electromagnetic field of the installed equipment is analyzed and discussed to determine the installation layout design of the equipment. When the converter power supply system operates at the steady-state rated current of 55 kA, the heat dissipation of the equipment is analyzed to determine the design of the cooling water system. The grounding of the system is calculated according to the application scenario. According to the equipment performance parameters and operation requirements of the PF converter system, the electrical, mechanical, and water system test and acceptance criteria test presented to ensure the state of system installation and integration and the safety and reliability of operation.

Vibration and Noise Optimization of Variable-Frequency-Driven SPMSM Used in Compressor Based on Electromagnetic Analysis and Modal Characteristics

The high-frequency electromagnetic noise caused by a frequency converter power supply has become the main composition of the vibration and noise of frequency-converter-driven PMSMs. Determining how to reduce this kind of noise is very important to improve motor performance. This paper analyzes the frequency characteristics of the high-frequency noise generated by an inverter, using the magnetic circuit analysis and Maxwell tensor methods. The switching frequency and the natural frequencies of the main modes are optimized according to the modal characteristics of the motor in order to reduce the vibration and noise of the motor. The results show that the high-frequency electromagnetic vibration and noise generated by the inverter is mainly caused by the high-frequency switching harmonic current. The frequencies of the vibration and noise are related to the switching frequency and the modulation wave frequency. At the same time, the simulation calculation of the natural frequencies of the main modes and the noise spectrum obtained from the experiment provide direction for the optimization of the vibration noise near the switching frequency. The switching frequency optimization and the natural frequency optimization based on the main modes of the motor can effectively reduce vibration and noise. This work has certain reference significance for the design of low-noise PMSMs.

Linear Active Disturbance Rejection Control of New Double Full-Bridge ZVZCS Converter for Beam Supply

In view of the unstable output voltage of the new double full bridge ZVZCS converter of beam power supply when it is disturbed by external disturbance or internal parameter change in practical application, combined with the characteristics of the beam power supply system model, this paper proposes a beam power supply control strategy based on linear active disturbance rejection control (LADRC). Firstly, the working principle of the new double full bridge ZVZCS converter of beam power supply is analyzed, and considering the parasitic parameters and effective duty cycle of circuit components, the small signal equivalent model under two working modes is established. Secondly, combined with the system model and linear active disturbance rejection control theory, a double closed-loop controller is designed, which takes the second-order LADRC as the outer voltage loop and PI control as the inner current loop. Finally, the simulation and experimental results show that the designed controller has stronger robustness, anti-interference and better dynamic response speed than the traditional double closed-loop PI controller in load switching and dual-mode switching, and has a good development prospect.

Design of single switch-boosted voltage current suppressor converter for uninterrupted power supply using green resources integration

Introduction. Uninterrupted power supply is the major requirement in the areas since it involves human lives. In the current scenario the demand and price of fossil fuels is increasing rapidly and availability also is not sufficient to the needs, an alternative identification to power generation is solar and wind energies. The purpose of designing an aimed, single switch boosted voltage and current suppressor (SS-BVCS) converter topology that interfaces both the wind and solar hybrid model. The method involves in the proposed chopper converter is derived by simply merging a switch and a pair of diodes and CLC filter which is used in realization of zero voltage switching for the main switch and a reversing diode to extract high voltage gain. The designed SS-BVCS converter topology can able to have a tight self-control on two power-processing paths. The novelty of the SS-BVCS converter module is designed to ensure maximum throughput, feeding to the load with high quality uninterrupted output, by boosting the DC voltage to a required amount and thereby supressing the current. Practical value obtained by the developed model utilizes both the sources for supply to the load individually or combined based on the extraction availability of the feeder. Also, the proposed SS-BVCS module delivers with efficient lesser component count and gaining maximum power from the harvest of green energy.

Application and Optimization of Luenberger Observer Phase-Locked Loop and Inductance-Free Vector Control Method for Aviation Three-Phase Converter in Wearable Equipment.

This work aims to strengthen the comprehensive performance of the Luenberger observer in the application of aviation three-phase converter and in physical exercise wearable devices to effectively detect human physiological signals. Firstly, the use status and characteristics of three-phase converters are discussed. Then, the Luenberger observer and its optimization process are described. Finally, the Luenberger observer is optimized through phase-locked loop technology and the vector control method. The experimental results indicate that the PLL of the steady-state linear Kalman filter is applicable to the multielectric aircraft converter for the aviation variable frequency power supply. The phase-locked loop of the steady-state linear Kalman filter is complicated, and the output angular frequency is inconsistent with the angular frequency of the actual voltage of the aircraft variable-frequency power supply. Consequently, it does not have the function of frequency locking. On the contrary, the Luenberger observer phase-locked loop designed here is suitable for the multielectric aircraft converter for the aircraft variable-frequency power supply. In addition, it is simpler than the steady-state linear Kalman filter phase-locked loop and realizes the frequency-locking function. In addition, the vector control method significantly improves the control performance of the Luenberger observer. The control error of the original observer is about 0.24°, and the control error of the optimized observer is about 0.18°. This work provides technical support for the performance optimization of the Luenberger observer and contributes to the performance improvement of the aviation three-phase converter.

Transient Synchronizing Stability of Droop-Controlled Converter during Grid Fault Considering Current Saturation Limitation

Traditional power systems usually rely on synchronous generators to provide inertia and maintain grid stability. However, with the continuous development of new energy power generation technologies, more and more converter power supplies provide voltage and frequency support for the power grid. The synchronizing instability issue of a converter-dominated power system becomes increasingly relevant, which exists in both grid-following (GFL) and grid-forming (GFM) converters. In this paper, the transient synchronizing stability of grid-forming (GFM) converters with droop-control during a grid fault is studied, with the influence of current saturation limitation considered especially. The current saturation limitation applied to limit overcurrent during grid faults brings transient voltage-source/current-source switched mode of the converter, which significantly influences the transient behavior. Considering the influence, an equivalent motion model similar to the rotor motion of a synchronous generator is developed first to depict the transient synchronizing dynamics. It has been identified that the current saturation limitation reconstructs the power angle characteristics, which significantly influence the transient stability. Then based on the developed model, transient synchronizing stability during a grid fault is studied based on the accelerating–decelerating area method. With the influence of grid impedance and grid voltage sag considered, several kinds of transient synchronizing stability issues are revealed clearly. Finally, simulated results are presented to verify the theoretical analysis. The analysis of this article paves the way for the follow-up research on the synchronizing stability of multi-converters and the corresponding control methods to improve synchronizing stability.