Self-Oscillating LED Driver With Bus Voltage Regulation

The paper deals with energy savings in Traction Systems available with Thyristor Controlled Rectifiers (TCR) and Reversible TCR (RTCR). TCR provides active voltage control, RTCR in addition has power recuperation into AC line. The energy balance of the TCR and diode rectifier systems are calculated, including losses in the rails, car’s power train and friction losses. The TCR advantages over diode rectifiers: better voltage regulation and fault current limiting allow us to reduce the number of substations and increase their service life. Major energy savings are through recuperation back to AC line using RTCR, with additional savings through increased DC bus voltage. The estimated energy savings depending on the system parameters, train speed profile, etc. can be as high as 50%.

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A Lean Satellite Electrical Power System with Direct Energy Transfer and Bus Voltage Regulation Based on a Bi-Directional Buck Converter

Aerospace ◽

10.3390/aerospace7070094 ◽

2020 ◽

Vol 7 (7) ◽

pp. 94

Author(s):

Juan J. Rojas ◽

Yamauchi Takashi ◽

Mengu Cho

Keyword(s):

Energy Transfer ◽

Power System ◽

High Reliability ◽

Voltage Regulation ◽

Buck Converter ◽

Electrical Performance ◽

Electrical Power System ◽

Direct Energy ◽

Bus Voltage ◽

Direct Energy Transfer

The lean satellite approach requires aggressive measures for cutting development time and resource utilization; therefore, the power system should be simple, with a low part count, high reliability, and good electrical performance. The fully-regulated bus direct energy transfer (FRDET) architecture is considered the most common solution for big satellites; however, it is rarely used in lean satellite designs because of its complexity and the lack of commercial off-the-shelf solutions. Based on this, a new implementation of the FRDET architecture was proposed, prototyped, and evaluated. The system was based on a bidirectional converter that charges and discharges the battery while maintaining the bus voltage regulation. The system was evaluated by comparing it with the prevailing architectures in the field, in terms of efficiency and average harvested solar power per orbit. The proposed system was superior in both aspects which made it more suitable for its application in lean satellite designs.

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Performance Evaluation of Series DC-ES for DC bus Voltage Regulation on Different Non-Critical Loads and Under FRT Support

2020 IEEE International Conference on Power Electronics, Smart Grid and Renewable Energy (PESGRE2020) ◽

10.1109/pesgre45664.2020.9070579 ◽

2020 ◽

Author(s):

S. P. Gawande ◽

R. N. Nagpure ◽

Kalyani Dhawad ◽

M. A. Waghmare ◽

Anurag R. Nagpure ◽

...

Keyword(s):

Performance Evaluation ◽

Critical Loads ◽

Voltage Regulation ◽

Dc Bus ◽

Bus Voltage

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Robust Control Method for DC Microgrids and Energy Routers to Improve Voltage Stability in Energy Internet

Energies ◽

10.3390/en12091622 ◽

2019 ◽

Vol 12 (9) ◽

pp. 1622 ◽

Cited By ~ 7

Author(s):

Haochen Hua ◽

Yuchao Qin ◽

Hanxuan Xu ◽

Chuantong Hao ◽

Junwei Cao

Keyword(s):

Power Transmission ◽

Control Method ◽

Voltage Regulation ◽

Normal Operation ◽

Local Network ◽

Linear Matrix ◽

Dc Microgrid ◽

Voltage Stabilization ◽

Energy Internet ◽

Bus Voltage

The energy internet (EI) is a wide area power network that efficiently combines new energy technology and information technology, resulting in bidirectional on-demand power transmission and rational utilization of distributed energy resources (DERs). Since the stability of local network is a prerequisite for the normal operation of the entire EI, the direct current (DC) bus voltage stabilization for each individual DC microgrid (MG) is a core issue. In this paper, the dynamics of the EI system is modeled with a continuous stochastic system, which simultaneously considers related time-varying delays and norm-bounded modeling uncertainty. Meanwhile, the voltage stabilization issue is converted into a robust H ∞ control problem solved via a linear matrix inequality approach. To avoid the situation of over-control, constraints are set in controllers. The problem of finding a balance between voltage regulation performance and constraints for the controllers was also extensively investigated. Finally, the efficacy of the proposed methods is evaluated with numerical simulations.

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Improved Dynamic Voltage Regulation in a Droop Controlled DC Nanogrid Employing Independently Controlled Battery and Supercapacitor Units

Applied Sciences ◽

10.3390/app8091525 ◽

2018 ◽

Vol 8 (9) ◽

pp. 1525

Author(s):

Ahmad M. A. Malkawi ◽

Luiz A. C. Lopes

Keyword(s):

Energy Storage ◽

Storage System ◽

Voltage Regulation ◽

Potential Contribution ◽

Pass Filter ◽

Power Sources ◽

Dynamic Voltage ◽

Dc Bus ◽

Bus Voltage ◽

The Impact

DC bus voltage signaling (DBS) and droop control are frequently employed in DC nano and microgrids with distributed energy resources (DERs) operating in a decentralized way. This approach is effective in enforcing the desired contributions of power sources and energy storage systems (ESSs) in steady-state conditions. The use of supercapacitors (SCs) along with batteries in a hybrid energy storage system (HESS) can mitigate the impact of high and fast current variations on the losses and lifetime of the battery units. However, by controlling the HESS as a single unit, one forfeits the potential contribution of the SC and its high power capabilities to dynamically improve voltage regulation in a DC nanogrid. This paper discusses an approach where the SC interface is controlled independently from the battery interface, with a small droop factor and a high pass filter (HPF), to produce high and short current pulses and smooth DC bus voltage variations due to sudden power imbalances in the DC nanogrid. Experimental results are presented to show that, unlike in a conventional HESS, the SC unit can be used to improve the dynamic voltage regulation of the DC nanogrid and, indirectly, mitigate the high and fast current variations in the battery.

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The Hierarchical Control Algorithm for DC Microgrid Based on the Improved Droop Control of Fuzzy Logic

Energies ◽

10.3390/en12152995 ◽

2019 ◽

Vol 12 (15) ◽

pp. 2995 ◽

Cited By ~ 4

Author(s):

Liang Zhang ◽

Kang Chen ◽

Shengbin Chi ◽

Ling Lyu ◽

Guowei Cai

Keyword(s):

Fuzzy Logic ◽

Control Algorithm ◽

Voltage Drop ◽

Hierarchical Control ◽

Voltage Regulation ◽

Droop Control ◽

Dc Microgrid ◽

Current Sharing ◽

The Difference ◽

Bus Voltage

In the direct current (DC) microgrid composed of multiple distributed generations, due to the different distances between various converters and the DC bus in the system, the difference of the line resistance will reduce the current sharing accuracy of the system. The droop control was widely used in the operation control of the DC microgrid. It was necessary to select a large droop coefficient to improve the current sharing accuracy, but a too large droop coefficient will lead to a serious bus voltage drop and affect the power quality. In view of the contradiction between the voltage regulation and load current sharing in the traditional droop control, a hierarchical control algorithm based on the improved droop control of the fuzzy logic was proposed in this paper. By improving the droop curve, the problems of voltage regulation and current sharing were solved simultaneously. The effectiveness of the algorithm was verified by simulation.

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