Parallel Power Supply Research Articles

Research on Stator Sections Switching Process of High-Thrust Linear Motors

The high-thrust linear motor used for the electromagnetic launch is switched by switches composed of anti-shunt thyristors. During the switching process, different current path states will appear, which will lead to changes in motor parameters and current fluctuation. Focusing on the air-core synchronous linear motor with parallel and series power supply, this paper analyzes the change in current path caused by the change in the trigger signal of anti-parallel thyristors in the process of sectionalized stator switching. The motor circuit model of the switching process is derived. A new sectionalized stators switching method is proposed to realize the smooth switching of the sectionalized stators linear motor. Finally, the correctness of the analysis and modeling is verified by simulation, and the effectiveness of the sectionalized stators switching method is tested by using the test prototype.

Research on Application of Three Closed-loop Autonomous Current Sharing Control Technology in Artillery Power System

The new artillery power system adopts the power supply mode of multiple power modules in parallel, which has the advantages of strong versatility, high power, high reliability, and low cost. The main difficulty lies in the current sharing of the power supply modules. Aiming at the shortcomings of traditional current sharing method such as low current sharing accuracy, poor dynamic response, poor output voltage stability, and low anti-interference ability, this article analyzes the necessity of parallel power supply current sharing and the principle of traditional average current sharing method, based on average current sharing method, a three-closed-loop autonomous current sharing control method is proposed, and a system model of power supply modules operating in parallel is established to realize the intelligent and autonomous average current distribution of power supply modules operating in parallel in the artillery power system to meet the power required by the load in the system. Through simulation analysis and prototype test, it is verified that the three closed-loop autonomous current sharing control has the advantages of high current sharing accuracy, fast dynamic response, good stability and strong robustness.

Research on Three-Port Converter for New Aerospace Energy Architecture

The traditional design method of spacecraft power systems based on customization and the combination of two-port converters can no longer meet the increasing application demands of having high power and being modular and versatile. Three-port DC converter, standardized to form a redundant parallel power supply system with a distributed model, is a possible solution to meet the design requirements of the above spacecraft power supply system. In this paper, a three-port converter is designed to complete the MPPT control of the PV array at the input end to maximize the power generated by the PV array, complete the battery charge and discharge control, realize the bidirectional conversion and transmission of the battery charge and discharge power, and complete the control of the load voltage at the output end to ensure the stable and reliable power supply of the load. If the integrated DC converter is used to realize the power transmission and conversion between the three ports at the same time, the volume and weight of the system can be greatly reduced, and then the power density of the system can be improved.

Design and analysis of robust backstepping controller for DC suppression of parallel UPS inverter system

AbstractHere, an improved control strategy is proposed, which adopts a non‐linear robust backstepping controller to eliminate DC circulating current in a parallel uninterruptible power supply (UPS) system. The traditional active and reactive power sharing control can ideally suppress the AC circulating current, but cannot effectively restrict the DC circulating current. Based on the traditional active power and reactive power sharing control (TAPRPSC) of the parallel UPS system, the proposed control strategy is used in each parallel inverter module to suppress the DC component disturbance in the inverter output voltage, which varies within a certain range. Hence the desirable steady‐state and dynamic performance of the system can be obtained. Moreover, the Lyapunov method is utilized to ensure the stability and robustness of the system. A parallel system of two UPS inverters with the proposed control strategy is built by Matlab/Simulink, and further experiments are carried out on the semi‐physical simulation platform of the Modelling Tech. Both the simulation and experimental results verify the effectiveness of the proposed control strategy for DC circulating current suppression and ideal output voltage tracking.

Research on AT traction network relay protection model based on Feeding Section

Relay protection for AT traction networks is the key to maintaining safe and reliable operation of high-speed railways. Existing relay protection in the electrical supply network of high-speed railways often ensures its reliability at the expense of its selectivity. The current reliability-first relay protection scheme no longer meets the current safety requirements for high-speed railway operations, so the need to select a more optimised relay protection scheme is crucial. The fully parallel AT power supply method used in high-speed railways has the Feeding Section as the basic unit. Optimising the relay protection mode of the Feeding Section is of great help in optimising the AT traction network relay protection system. In this paper, the IED model for the protection of the entire Feeding Section is established by building a model based on the relevant rules of the IEC 61850 communication protocol and configuring the parameters of each logical node, starting from the actual project of the high-speed railway. The OPNET software was used to carry out simulations to prove that the IED model for line protection based on the supply arm can effectively balance the reliability and selectivity of relay protection.

LED Lighting Agrosystem with Parallel Power Supply from Photovoltaic Modules and a Power Grid

The paper considers the operation of an LED lighting system with a parallel power supply from photovoltaic modules and a power grid. Such systems are supposed to be widely applicable in premises with limited natural lighting, particularly agrosystems where artificial light of a certain spectrum is specifically required to ensure efficient plant growth. The paper presents the scheme of the developed LED lighting system, as well as an assembled prototype containing a single 36-watt lamp. The data of the experimental study are provided on the developed LED lighting system using the developed monitoring system. The experimental study demonstrates an efficient power take-off and the reliability of the proposed scheme to competently select the characteristics and circuit solutions for the converter of voltage from the PV module. The proposed LED system allows simplification of the PV system by eliminating circuits with an inverter and storage devices, hence significantly reducing the cost of the photovoltaic systems. Likewise, such a simplicity has a positive effect on PV system reliability, which benefits the cost as well.

Research on parallel output method of DC regulated power supply

This paper describes the output characteristics of DC regulated power supply in spacecraft ground test system and proposes a scheme of DC regulated power supply parallel output with remote sampling. Then the power-on and power-off procedure as well as the characteristics of normal operation in space vehicle using ground power supply are analyzed.The transient characteristics of parallel power supply are summarized. This method with simple circuit connection is able to meet the power supply requirements of spacecraft as well as improve the reliability and security of power supply system. Experimental verification demonstrates the effectiveness of the proposed method. It solves the problem of heavy load energy requirement of spacecraft in ground test and verification stage.

Distributed Hierarchical Control With Separation of Concerns for Parallel-Connected UPSs

This article presents a distributed hierarchical control structure for parallel uninterruptible power supplies. A dynamic approach with separation of concerns is proposed for the secondary control, where a so-called grid forming inverter is responsible for restoring the amplitude and frequency of the output voltage, while the remaining inverters, called grid supporting, are responsible for enhancing long-term power sharing. This strategy aims to minimize the tradeoff between voltage regulation and power sharing through secondary control, which uses a low bandwidth communication link. For the primary controller, resistive droop control with virtual resistance is employed to accomplish short-term power sharing. Simple design guidelines for the secondary controllers based on simplified models developed in the article are provided. Extensive experimental results obtained from two 500-VA prototypes demonstrated the good performance of the proposed strategy. The amplitude and power sharing errors remained below 1% and 2%, respectively, for the entire load range evaluated.

Photovoltaic Thermal Module With Paraboloid Type Solar Concentrators

The article presents the results of the development and research of the solar photovoltaic thermal module with paraboloid type solar radiation concentrators. The structure of the solar module includes a composite concentrator, which provides uniform illumination by concentrated solar radiation on the surface of the cylindrical photovoltaic thermal photoreceiver in the form of the aluminum radiator with photovoltaic converters. When exposed in concentrated solar radiation, the electrical efficiency of specially designed matrix photovoltaic converters increases, and the heat taken by the heat carrier increases the overall efficiency of the solar module. Uniform illumination of photovoltaic converters with concentrated solar radiation provides an optimal mode of operation. The consumer can use the received electric and thermal energy in an autonomous or parallel power supply with the existing power grid.

Switched ring antenna array with electronic scanning

For operation in the frequency range of 5,1–5,9 GHz, a directional antenna device has been developed for use as part of a base station in a stationary point-to-multipoint system with a controlled beam position. The antenna device is a switched, broadband, ring antenna array with electronic scanning in the azimuthal plane. Its distinctive feature is high gain of the radiating elements, which are used as linear printed antenna arrays with parallel power supply. The required directional characteristics and matching of the emitters have been achieved in the process of parametric synthesis carried out using the CST MS program. In a given frequency range, the emitters are characterized by the following parameters: width of the main lobe of the directional pattern in the E-plane is 6,6…7,5 deg; level of the first side lobe in the E-plane is 0…–11,4 dB; width of the main lobe of the directional pattern in the H-plane is 53,2…73,4 deg; level of the first side lobe in the H-plane is –23,4…–26,4 dB; gain is 17,0…17,5 dB; the reflection coefficient at the input of the emitters does not exceed 0,2. In the horizontal plane the main lobe of the directional pattern at different frequencies is shifted by an angle of 5–10 deg relative to the normal to the radiating opening of the emitters. The reason is a microstrip distributor combined with printed antenna array emitters on a common printed circuit board. The specified offset of the main lobe of the directional pattern does not decrease the functional characteristics of the antenna device, because the difference in level in the direction of the main maximum and in the direction normal to the radiating aperture of antenna arrays does not exceed 0,5 dB. In addition, the specified offset at the given frequency is regular and has the same value for all emitters of the ring antenna array. Therefore, the angular discret and the level of overlap of the directional patterns of the neighboring emitters when scanning in the azimuthal plane remain unchanged. The results of an experimental study of a prototype antenna device have been presented. They are in good agreement with the results of computer modeling.

СИСТЕМА СВЕТОДИОДНОГО ОСВЕЩЕНИЯ В СМЕШАННЫХ СЕТЯХ ПОСТОЯННОГО И ПЕРЕМЕННОГО ТОКА

The article discusses the operation of the LED lighting system with parallel power supply from photovol¬taic modules and the power grid. The paper describes the scheme of the developed LED lighting system, on the basis of which a working sample with a single 36 W lamp was assembled. Experimental studies of the LED lighting system using the developed monitoring system have been carried out. The paper presents the part of the experimental data. The working sample in practice demonstrated the effectiveness and reliability of the proposed scheme. The article presents a working alternative for the efficient connection of photovoltaic modules to the load using inexpensive converters.

Comprehensive Evaluation for Design for Design Scheme of Metro Auxiliary Power supply System Based on FAHP

Considering the main factors that affect the design scheme of power supply system, the fuzzy analytic hierarchy process (FAHP) is used to comprehensively evaluate the design scheme of metro auxiliary power supply system. Firstly, the evaluation model of the auxiliary power supply system design scheme is established, and the factors influencing the system evaluation are divided into two levels, and the factor evaluation grade is the third level. Secondly, analytic hierarchy process (AHP) is used to determine the weight of each factor, and the method of triangular fuzzy number is used to establish a comprehensive evaluation matrix. Finally, the three-level fuzzy comprehensive evaluation is carried out based on the principle of fuzzy transformation, and the comprehensive evaluation results of each design scheme are calculated. The research results show that the comprehensive evaluation score of the parallel centralized power supply mode is the highest, and the design scheme is the best, which is consistent with the actual application. It shows that the method can directly reflect the advantages and disadvantages of each design scheme, and provide some reference for the selection of the design scheme of the auxiliary power supply system of the metro.

English

English

Energy-Saving Led Lighting System With Parallel Power Supply By Photovoltaic Modules And By Network

The current state of LED lighting systems with parallel power supply by photovoltaic modules and central power supply network is analysed. The approach to implementation of parallel operation of LED luminaire powered by two sources of power is presented. It is simple, cheap and highly reliable as compared to the existing solutions. Based on this approach, four diagrams are developed which are applicable correspondingly to lighting applications and characteristics of photovoltaic modules and power consumers. The first and the second diagrams contain minimal quantity of transformers, but a number of operational constraints shall be taken into account when using them. The third diagram contains standard transformers and implies minimal number of various constraints, which makes it an optimal solution for the low-power lighting system being designed. The fourth diagram is expensive due to utilisation of equipment with automatic maximum power point tracking (the MPPT technology); it provides maximum possible energy efficiency of the lighting systems but the advantages of the MPPT technology apply only to high-power systems. It is preferable to use such objects where lighting is mostly required during daytime as consumers of such systems (shopping malls, underground passages, storage facilities, poultry farms, etc.). A positive aspect is increase in reliability of consumer power supply since power supply of LED luminaires will be also provided by an additional source. The proposed approach leads to reduction of power consumption for LED lighting, saving of fossil energy sources and therefore to ecologisation of the environment.

Performance comparison of series and parallel DC power supply system

Since the structure of series DC power supply system, if any battery cell breaks down, the group of battery cells can’t play its due role. The parallel DC power supply system has been successfully developed and applied in recent years. We want to know whether the parallel DC power system is worth vigorously popularizing and applying in the substation in the future? So we made a few special tests, and this paper will compare the series and parallel DC power supply systems with some data in some ways, such as performance, safety, reliability, maintenance quantity, convenience, economic benefits, etc.

An Effective Solution for Regeneration Protection in Uninterruptible Power Supply

In this paper, a regeneration protection solution is proposed to address the dc-link overvoltage issue and the unequal power sharing in the parallel uninterruptible power supply (UPS) systems. First, a dc-link voltage protection control strategy is proposed to protect the inverter against the excessive dc-link voltage that may trigger the protection mechanism of the UPS system. In addition, an active power-sharing control strategy by regulating the virtual resistance is proposed to solve the circulating current caused by UPS regeneration issue. Finally, the feasibility of the proposed regeneration protection solution is verified by experimental results from the parallel UPS system prototype.

Research on High Efficiency V/f Control of Segment Winding Permanent Magnet Linear Synchronous Motor

By analyzing the relationship between the electromagnetic parameters and the secondary position during the primary and secondary coupling transition of the segment winding permanent magnet linear synchronous motor (SW-PMLSM), the variable parameter mathematical model of the rotor side of the SW-PMLSM is established. Taking the three-stage primary lifting system as an example, the dynamic process of the whole system is simulated and analyzed. According to the characteristics of its parameters, the segmentation vector control is obtained as the best stability control method. However, in practical applications, in order to save costs, the segmented linear motor often adopts the effective section parallel power supply mode, and the SW-PMLSM parallel power supply model is obtained by approximate simplification. This paper proposes a SW-PMLSM high-efficiency V/f control method, which combines the advantages of traditional V/f control and field-oriented control. It does not need to install position sensor, and can realize simple and high-performance motor drive. Finally, simulation and experimental results are provided to validate the effectiveness of the fidelity of the proposed strategy.

DC-Link Protection and Control in Modular Uninterruptible Power Supply

In this paper, a dc-link voltage protection (DCVP) control method is proposed to address the dc-link overvoltage issue due to power backfeeding in a parallel uninterruptible power supply (UPS) system. The proposed control method is able to protect the inverter against the excessive dc-link voltage, which increases the system reliability and robustness. Moreover, a current sharing control strategy is proposed by online regulating the virtual resistance of each UPS module. The proposed current sharing control strategy is able to address the circulating fundamental and harmonic currents caused by the line impedance mismatching or power backfeeding issue in the UPS system. In addition, an improved consensus-based distributed controller is proposed to alleviate the overshoot issue during the transient process in voltage amplitude and frequency restoration. Finally, the feasibility of the proposed methods is verified by experimental results from the parallel UPS prototypes.

Modeling and Simulation of Variable Speed Variable Frequency Electrical Power System in More Electric Aircraft

The More Electric Aircraft (MEA), Variable Speed Variable Frequency (VSVF) and Electrical Power System (EPS) has lager generating capacity and higher energy efficiency than the conventional Constant Speed Constant Frequency EPS, but the generators of MEA have to working as redundant power supplies to improve the power supply reliability, instead of parallel power supply. To study the steady state operation and power source change strategies under different fault conditions of VSVF EPS, the integrated structure of VSVF EPS is firstly illustrated and operating principles of components are theorized. The key components including variable frequency generators, Bus Power Control Unit, rectifiers and other supplementary elements are then simulated to build a comprehensive VSVF EPS model on the platform of Simulink and the power source change strategies are realized by logic units. Finally, the stability analysis in terms of normal operation is carried out in case studies and power source exchange strategies in different situations are summarized. The results show that the model proposed by the paper can be used to simulate MEA VSVF EPS and analyze its whole operational process effectively and efficiently.

Research on Output Current Sharing and Synchronous Start-Up in Parallel Power Supply Modules

With the development of the distributed power system, the paralleled switching mode power supplies are becoming more and more important for large current load. However, paralleled system usually requires load sharing to equalize stresses, and while a lot of techniques have been used, there are many compromises between complexity and performance. This paper introduces the superiority of the power supply modules in parallel, discusses both the advantages and disadvantages of the usual current sharing methods. Finally, some suggestions to enhance redundancy and reliability for current sharing modules have been proposed.