Reduced DC Bus Voltage Research Articles

An improved microgrid energy management system based on hybrid energy storage system using ANN NARMA-L2 controller

This research describes an intelligent Energy Management System (EMS) for a microgrid application that employs a Nonlinear Autoregressive Moving Average Level 2 (NARMA-L2) artificial neural network (ANN). The hybrid energy resources (PV/WIND), a hybrid energy storage system (HESS) with batteries and supercapacitors (SC), and loads are all integrated into the microgrid. Maximum Power Point Tracking (MPPT) in a photovoltaic (PV) system is based on the Nonlinear Autoregressive with exogenous inputs (NARX) approach. The flowchart, rules, memberships, and scenarios that allocate energy among various components based on battery State of Charge (SoC), PV/wind power, and load factors are described in the article. To validate the EMS's effectiveness, simulation tests under various conditions are presented. Supercapacitors (SCs) reduce DC bus voltage swings, lowering battery stress and extending battery life, it has been demonstrated using various load variations, as well as various sun irradiation and wind speed values under various conditions. The simulation results in the MATLAB/Simulink environment, validate the effectiveness of the proposed approach and produce effective DC BUS stabilizing and maintaining frequency stability of system that shows the importance and efficiency of the control strategy used.

A Novel Proportional Multi-Resonant Current Controller Strategy for Reduced DC Voltage fed D-STATCOM with Internal LCL Resonance Damping

Abstract This work focuses on a new topology-control-based D-STATCOM solution with reduced DC bus voltage requirement and with an excellent grid side performance. The proposed solution consists of a main inverter and auxiliary inverter along with a transformer and LCL filter network to achieve the required DC bus reduction. A new controller structure with two proportional-multi resonant controller for the converters with only one of the inductors current as a controlled variable ensures the active damping of the LCL resonance. The power circuit configuration assists the controller to generate a difference in the modulation signal due to non-equal gains in two controllers and helps to achieve the resonance damping without capacitor current sensor. Hence, the corresponding capacitor current sensor can be eliminated. The converter operates for any point of common coupling (PCC) loading conditions and the performance of the controller is immune to the grid impedance variation. A detailed stability study is carried out for the proposed controller. The proposed controller can achieve a very fast dynamic response with an excellent stability margin. The proposed solution is verified through simulation studies and through a scaled-down experimental prototype.

Adaptive Fuzzy Logic-Based Control and Management of Photovoltaic Systems with Battery Storage

Renewable energy sources (RESs) such as solar photovoltaic (PV) systems are increasingly used as distributed generation for replacing the conventional energy. At the same time, energy storage systems like battery (BAT) must be applied for maintaining the balance between fluctuating energy production and load consumption. BAT’s state of charge (SOC) should be maintained within their design limits unaffected by RES intermittency and/or load power variations. This necessitates advanced power control and management methodologies for overcoming challenging conditions. This paper discusses and evaluates an optimal DC bus voltage regulation approach: an intelligent controller using an adaptive fuzzy logic controller (FLC) and a novel supervisory power management strategy for PV systems with BAT. The objectives are to keep a stable power flow in the system and guarantee the continuity of service by ensuring that the system components do not exceed their limits. In this manner, the DC bus voltage regulation of the PV/BAT system can be improved in comparison with conventional regulation. Therefore, the most important contributions of this work are as follows. (1) Development of comprehensive and modular novel energy management system (EMS): its originality is related to the inclusion of the control system limits with faster SOC balancing and smaller DC bus voltage fluctuation. (2) Providing a simple power flow management implementation that considers the optimal energy flow between PV system, BAT system, and load: a balance between minimal energy flow in the connecting line and the least requirements of BAT capacity is kept, reducing component constraints with a very straightforward structure. (3) Furthermore, FLC offers high robustness and smooth performances. FLC is added to the control strategy design requirements to reduce DC bus voltage deviation. (4) Real-time simulation/experimentation-based complete cases utilizing Matlab/Simulink and DSpace are illustrated to testify the effectiveness of the proposed FLC and EMS.

A Three-Parameter Adaptive Virtual DC Motor Control Strategy for a Dual Active Bridge DC–DC Converter

Increasingly more power electronic devices are being connected to DC microgrids, which reduces the inertia of a DC microgrid, and the DC bus voltage has poor resistance to disturbance. Adding a virtual DC motor control to the converter can effectively suppress the fluctuation of the DC bus voltage; however, due to the fixed inertia and damping parameters, the system cannot attain a good dynamic performance. On this basis, a two-parameter adaptive virtual DC motor control is proposed to realize flexible change both in terms of inertia and damping, which improves the stability of the DC bus, and the system has good dynamic performance under this control. To further improve the stability of DC bus voltage and the flexibility of the microgrid control, in this paper, a dual active bridge (DAB) DC–DC converter controlled by dual phase shift (DPS) is taken as the research object, a three-parameter adaptive virtual DC motor control strategy is proposed to realize the flexible adjustment of inertia, damping, and armature resistance at the same time, and meanwhile, optimize the backflow power and inductor current stress of the converter. Finally, simulation and experiment results show that the proposed three-parameter adaptive control strategy compares with the two-parameter adaptive control strategy, and it can further reduce DC bus voltage fluctuation and recovery time, which improve the stability of the DC bus and the dynamic performance of the system. The DC bus voltage fluctuation rate under the three-parameter adaptive control is reduced to 9%, and the voltage recovery time is only 0.18 s; the optimization strategy can also effectively reduce the backflow power and inductor current stress.

Implementation of a low cost, compact single stage power converter with reduced bus voltage stress

Over the recent past, many methodologies to reduce DC bus voltage stress in the single stage single switch power quality converter have been proposed in the literature. The new development resulted in increased efficiency, reduced size and compactness. In this paper, a simple and inexpensive solution with a simple control for the reduction of DC bus voltage stress is proposed. This topology is the integration of discontinuous conduction mode (DCM) boost rectifier for the input current shaping and flyback converter for fast output voltage regulation. With a single active switch, this converter is capable of drawing high quality input current waveform, fast output voltage regulation with reduced bus voltage. No additional component is required to reduce DC bus voltage stress. A design solution and a simple controller is proposed to reduce DC bus voltage stress. As a result, this converter is best suited for universal line application (90-265 V AC). Performance of the converter, design guidelines, small signal analysis, and stability analysis are carried out.

Review of the Impact of Parameter Variation on the Operating Speed Range of the Interior Permanent Magnet Synchronous Machine

This paper systematically reviews the impact of the parameter variation on the power-speed characteristic of the interior permanent magnet synchronous machine while running with vector current control methods. The authors attempt to study the impact of the stator resistive drop, variation of the magnet flux-linkage, saturation, cross-coupling, and the reduced DC bus voltage on the voltage limits and trajectories for motoring and generation modes. Primarily, the stator resistive drop causes the difference in the base speeds of motoring and generation modes. On the other hand, the reduction in the DC bus voltage affects the starting point of the pseudo-constant power speed range. The saturation and cross-coupling affects the motoring and generation similar way by distorting the voltage limit ellipses and trajectories.

Review of the impact of parameter variation on the operating speed range of the interior permanent magnet synchronous machine

This paper systematically reviews the impact of the parameter variation on the power-speed characteristic of the interior permanent magnet synchronous machine while running with vector current control methods. The authors attempt to study the impact of the stator resistive drop, variation of the magnet flux-linkage, saturation, cross-coupling, and the reduced DC bus voltage on the voltage limits and trajectories for motoring and generation modes. Primarily, the stator resistive drop causes the difference in the base speeds of motoring and generation modes. On the other hand, the reduction in the DC bus voltage affects the starting point of the pseudo-constant power speed range. The saturation and cross-coupling affects the motoring and generation similar way by distorting the voltage limit ellipses and trajectories.

A Design Solution to Reduce DC Bus Voltage Stress in Single Switch Power Quality Converter

Power quality is becoming an important issue for electricity consumers at all level of usages. Sensitive equipment and non-linear loads are common in both industrial and domestic environment. Harmonic distortion can result in malfunction of sensitive equipments and generators. Power factor corrected converter is increasingly used in industry to improve input current quality and regulate the output voltage of front end converter. This paper presents a Single Switch Power Quality Converter which achieves both power factor correction and output voltage regulation by using only one switch. This paper deals with the design method in the reduction of DC bus voltage stress during light load, by selecting proper boost inductor using Equal Area Criterion (EAC).

A Low-Power AC–DC Single-Stage Converter With Reduced DC Bus Voltage Variation

A new low-power single-stage ac-dc converter is proposed in the paper. The outstanding feature of the converter is that it can operate with a sinusoidal input current and a low primary-side dc bus voltage that is much less variable than that found in other single-stage converters. The operation of the converter is discussed in the paper and its various modes of operation are explained in detail. An analysis of the converter's steady-state characteristics is performed and the results are used in the design of the converter. Experimental results obtained from a prototype converter are also presented.

An Improved AC–DC Single-Stage Full-Bridge Converter With Reduced DC Bus Voltage

A new ac-dc single-stage voltage-fed pulsewidth-modulation (PWM) full-bridge converter is proposed in this paper. The converter can simultaneously perform input power factor correction and dc-dc conversion using conventional phase-shift PWM and can maintain a primary-side dc bus voltage of less than 450 V even at a high input line voltage of 265 Vrms. This is a combination of features that few, if any, other converters of the same type have. The proposed converter has these features due to the novel implementation of an asymmetrical auxiliary transformer winding that is placed in series with the input inductor and acts as a boost switch. In this paper, the operation of the proposed converter is explained in detail, its outstanding features are discussed, and a detailed design procedure is given and demonstrated with an example. Experimental results that confirm the feasibility of the converter and its ability to meet IEC1000-3-2 Class D standards for electrical equipment are also presented in this paper.