scholarly journals Disturbance Rejection and Control Design of MVDC Converter with Evaluation of Power Loss and Efficiency Comparison of SiC and Si Based Power Devices

Electronics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1878
Author(s):  
Faisal Mehmood Shah ◽  
Sarmad Maqsood ◽  
Robertas Damaševičius ◽  
Tomas Blažauskas
Keyword(s):  
Power Generation ◽  
Power Loss ◽  
Power Flow ◽  
Low Voltage ◽  
Effective Control ◽  
Current Loop ◽  
Industrial Facilities ◽  
Loop Control ◽  
Dc Power ◽  
Loss Efficiency

With direct current (DC) power generation from renewable sources, as well as the current relocation of loads from alternating current (AC) to DC, medium-voltage DC (MVDC) should fill gaps in the areas of distribution and transmission, thereby improving energy efficiency. The MVDC system is a platform that interconnects electric power generation renewables (solar, wind) with loads such as data centers, industrial facilities and electric vehicle (EV) charging stations (also using MVDC technology). DC–DC power converters are part of the rising technology for interconnecting future DC grids, providing good controllability, reliability and bi-directional power flow. The contribution of this work is a novel and efficient multi-port DC–DC converter topology having interconnections between two converters, three-level neutral point clamping (NPC) on the high-voltage (HV) side and two converters on the low-voltage (LV) side, providing two nominal low voltages of 400 V (constant) and 500 V (variable), respectively. The design of this new and effective control strategy on the LV side has taken into condition load disturbances, fluctuations and voltage dips. A double-closed-loop control topology is suggested, where an outside voltage control loop (in which the capacitance energies are analyzed as variable, and the inside current loop is decoupled without the precise value of boost inductance) is used. The simulation results show the effectiveness of the proposed control system. In the second part of this study, wide-bandgap SiC and Si devices are compared by using comprehensive mathematical modeling and LT-spice software. Improving power loss efficiency and overall cost comparisons are also discussed.

scholarly journals Improvement of Power Quality Considering Voltage Stability in Grid Connected System by FACTS Devices

2013 ◽  
pp. 182-187
Author(s):  
Sarika D. Patil
Keyword(s):  
Power Generation ◽  
Wind Power ◽  
Power Flow ◽  
Voltage Stability ◽  
Low Voltage ◽  
Wind Power Generation ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Induction Generators ◽  
Facts Devices

Recently the wind power generation has attracted special interest and many wind power stations are being in service in the world. In the wind turbine that mostly uses induction generators, tend to drain large amounts of Vars from the grid, potentially causing low voltage and may be voltage stability problems for the utility owner, especially in the case of large load variation on distribution feeder. Voltage-source converter based various FACTS devices have been used for flexible power flow control, secure loading and damping of power system oscillations. Some of those are used also to improve transient and dynamic stability of the wind power generation (WPGS).

A new scheme for power factor correction and active filtering for six-pulse converters loads

2009 ◽  
Vol 57 (2) ◽  
pp. 157-169 ◽  
Author(s):  
Y. Han ◽  
M. Khan ◽  
L. Xu ◽  
G. Yao ◽  
L. Zhou ◽  
...  
Keyword(s):  
Power Factor ◽  
Power Flow ◽  
Power Factor Correction ◽  
Active Power ◽  
Estimation Accuracy ◽  
Voltage Source ◽  
Current Loop ◽  
Loop Control ◽  
Proportional Integral ◽  
Active Filtering

A new scheme for power factor correction and active filtering for six-pulse converters loads This paper presents a novel harmonic-free power factor correction (PFC) topology based on T-type active power filter (APF), which is dedicated for power factor improvement and harmonic filtering for six-pulse converter loads. The cascaded controller structure is adopted for the proposed system, namely, the inner current loop and outer voltage loop. The current-loop control scheme is based on a decoupled state-space equations of the T-type APF using separate proportional-integral (PI) controllers in d-axis and q-axis of the synchronous rotating reference frame (SRRF) synchronized with grid voltages, respectively. The fundamental components of load-side currents are feed forwarded in the current-loop using two groups of synchronous frame adaptive linear neural networks (ADALINEs) to ensure estimation accuracy and a fast dynamic response. A separate proportional-integral (PI) controller is adopted in the outer voltage loop for balancing the active power flow of the voltage source inverter (VSI) dc-side capacitor. The experimental results confirm well with the theoretical analysis.

scholarly journals Fluctuation Suppression of DC-Link Voltage Using Control of Converters Connected with DC Distributed Generation

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5832
Author(s):  
Sang-Jae Choi ◽  
Sung-Hun Lim
Keyword(s):  
Power Generation ◽  
Distributed Generation ◽  
Low Voltage ◽  
Renewable Energy Sources ◽  
Voltage Fluctuation ◽  
Voltage Fluctuations ◽  
Dc Voltage ◽  
Low Voltage Ride Through ◽  
Dc Power ◽  
Fault Ride Through

Due to the increase in DC load and DC Power generation, the need for DC power system is emerging. Accordingly, FRT (fault ride through) and LVRT (low voltage ride through), which are related regulations for renewable energy sources, have been enacted, and operation algorithms of each converter are required for this. However, the operation of the converter according to LVRT regulations causes DC voltage fluctuations. In the current study, DC voltage fluctuation is suppressed through converter control of DC-linked battery. The controller was designed from the relational equation between DC voltage and instantaneous power of battery. The pattern of DC voltage fluctuations to the output of the PV (photovoltaic), which is a DC power generation source, was confirmed, and voltage fluctuation suppression was verified by applying the designed converter cooperation algorithm and controller.

Linear power flow formulation for low-voltage DC power grids

2018 ◽  
Vol 163 ◽  
pp. 375-381 ◽  
Author(s):  
Oscar Danilo Montoya ◽  
L.F. Grisales-Noreña ◽  
D. González-Montoya ◽  
C.A. Ramos-Paja ◽  
Alejandro Garces
Keyword(s):  
Power Flow ◽  
Low Voltage ◽  
Power Grids ◽  
Dc Power

An improved Newton-Raphson based linear power flow method for DC grids with dispatchable DGs and ZIP loads

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hongwei Li ◽  
Xiao Wang ◽  
Junmu Lin ◽  
Lei Wu ◽  
Tong Liu
Keyword(s):  
Power Flow ◽  
Low Voltage ◽  
Power Grid ◽  
Linear Method ◽  
Constant Current ◽  
Droop Control ◽  
Current Case ◽  
Content Type ◽  
Dc Power ◽  
Newton Raphson

Purpose This study aims to provide a solution of the power flow calculation for the low-voltage ditrect current power grid. The direct current (DC) power grid is becoming a reliable and economic alternative to millions of residential loads. The power flow (PF) in the DC network has some similarities with the alternative current case, but there are important differences that deserve to be further concerned. Moreover, the dispatchable distributed generators (DGs) in DC network can realize the flexible voltage control based on droop-control or virtual impedance-based methods. Thus, DC PF problems are still required to further study, such as hosting all load types and different DGs. Design/methodology/approach The DC power analysis was explored in this paper, and an improved Newton–Raphson based linear PF method has been proposed. Considering that constant impedance (CR), constant current (CI) and constant power (CP) (ZIP) loads can get close to the practical load level, ZIP load has been merged into the linear PF method. Moreover, DGs are much common and can be easily connected to the DC grid, so V nodes and the dispatchable DG units with droop control have been further taken into account in the proposed method. Findings The performance and advantages of the proposed method are investigated based on the results of the various test systems. The two existing linear models were used to compare with the proposed linear method. The numerical results demonstrate enough accuracy, strong robustness and high computational efficiency of the proposed linear method even in the heavily-loaded conditions and with 10 times the line resistances. Originality/value The conductance corresponding to each constant resistance load and the equivalent conductance for the dispatchable unit can be directly merged into the self-conductance (diagonal component) of the conductance matrix. The constant current loads and the injection powers from dispatchable DG units can be treated as the current sources in the proposed method. All of those make the PF model much clear and simple. It is capable of offering enough accuracy level, and it is suitable for applications in DC networks that require a large number of repeated PF calculations to optimize the energy flows under different scenarios.

An Experimental Performance Evaluation of DC Power Generation and Power Loss in Full-Bridge Rectifier of Cantilever Type of Piezoelectric Vibration Energy Harvester

2010 ◽  
Author(s):  
Kazuhiko Adachi ◽  
Tohru Tanaka
Keyword(s):  
Power Generation ◽  
Resonant Frequency ◽  
Power Loss ◽  
Energy Harvester ◽  
Rotating Machinery ◽  
Vibration Energy ◽  
Vibration Energy Harvester ◽  
Full Wave ◽  
Dc Power ◽  
Bridge Rectifier

Rotating machinery is widely used in the industrial plant. In order to ensure safety operation of the rotating machinery, vibration condition monitoring of the machinery can play a crucial role. Authors have proposed a cantilever type of vibration energy harvester for vibration condition monitoring applications of rotating machinery. Proposed energy harvester consisted of Macro-Fiber Composite (MFC). In this study, not only the DC power generation performance but also power loss in full-wave bridge rectifier of the proposed vibration energy harvester is experimentally evaluated. The maximum DC output power through 287.6(kΩ) resistor which includes instruments internal resistances obtained 109.5(μW) when subjected to vibration source input magnitude of 0.71(mm/s rms) at the resonant frequency of the harvester. The impedance matching between MFC actuators and the electrical resistive load was also effective for maximizing the DC power transfer of the vibration energy harvester. The power loss in full-wave bridge rectifier reached 13.7(μW) at the resonant frequency.

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