An Auxiliary Power Supply for Gate Drive of Medium Voltage SiC Devices in High Voltage Applications

2018 ◽  
Vol 924 ◽  
pp. 836-840
Author(s):  
Bo Xue Hu ◽  
He Li ◽  
Zhuo Wei ◽  
Ya Feng Wang ◽  
Diang Xing ◽  
...  

A high-reliability auxiliary power supply (APS) for gate drive circuits is crucial to utilization of emerging medium voltage (MV ≥ 10 kV) Silicon Carbide (SiC) devices in high voltage applications. This paper proposes an active voltage divider based APS with lower arm voltage regulation. The proposed APS circuit is targeting the application of MV SiC devices in modular multilevel converters (MMCs). It can harvest energy from a MV (≥ 7 kV) dc bus to provide an isolated low voltage output to gate drive circuits of MV SiC devices. Compared to existing APS solutions, it can achieve a high input voltage (≥ 7 kV) with simple circuit structure and control scheme. In this paper, the working principle of the proposed APS is presented and a circuit design example is shown. A circuit prototype with 7 kV input and 15 V/10 W output has been built and tested to verify the effectiveness of the proposed solution.

2016 ◽  
Vol 25 (06) ◽  
pp. 1650064 ◽  
Author(s):  
Hongbo Ma ◽  
Junhong Yi ◽  
Jie Shuai ◽  
Jie Yang

High input voltage, multiple low voltage outputs and high working temperature are the main design challenges for magnetic levitation (maglev) control power supply. The traditional solutions have several problems, such as the uncontrolled duty ratio, the poor cross-regulation capability and low reliability. In order to solve these problems, a quasi-single-stage solution employing the double resonant tank LLC topology is proposed and developed in this paper. The proposed solution can increase significantly the overall conversion efficiency because of the achieved soft-switching over the entire operation range. Moreover, the low input current ripple, high magnetic utilization and high reliability can be achieved. Experimental results of a 210-W laboratory prototype with 220–380[Formula: see text]V input and four outputs are presented to demonstrate the declared features.


Author(s):  
Bolarinwa H.S. ◽  
Fajingbesi F.E. ◽  
Yusuf A. ◽  
Animasahun L. O. ◽  
Babatunde Y. O.

A high voltage power supply is a key component in the advancement of science and technology. Application of high voltage power supply requires careful attention to critical variables such as voltage ripple, long and shortterm stability, repeatability and accuracy. These are important factors in the consideration of reliable scientific data. This paper presents the design of a low-cost high voltage power supply from the off-the-shelf electronics components to meet the high-end requirement of high voltage power supply. A 30kV, 63.8mA maximum power supply was constructed at the Fountain University electronics workshop. This high voltage directs current (HVDC) power supply was built around three basic compartments that include an adjustable low voltage power supply (LVPS), a high frequency oscillator, and a line output transformer (LOPT) using flyback transformer, NE555timer, BU508D BJT, and other off-the-shelf components. The current-voltage relationship at the output of the constructed High Voltage Direct Current was found to be linear. This power source will serve any high DC voltage applications such as electrospinning. The constructed 30kV power supply has been tested in the electrospinning laboratory of the Center for Energy Research and Development (CERD) Obafemi Awolowo University (OAU) Ile-Ife. The unit successfully electrospun Zinc-Titaninm polymeric solution into fibers at about 8 kV. The importance of this fabricated device is its high reliability despite its low cost and capability to produce different magnitude of high voltage DC.


2021 ◽  
Author(s):  
Lin Zhu ◽  
Chushan Li ◽  
Huan Yang ◽  
Huiqiang Yan ◽  
Wuhua Li ◽  
...  

2013 ◽  
Vol 732-733 ◽  
pp. 958-964
Author(s):  
Yao Zhao ◽  
Yu De Yang ◽  
Yan Hong Pan ◽  
Le Qi

The feasibility of transformer fast reenergizing with neutral point ungrounded after the external fault being removed is analyzed in this paper. By calculating overvoltage and discriminating magnetizing inrush current, it analyzes four ways to restore power of transformer and chooses the optimal strategy which is safe and time-saving. The result shows that in the case of transformer neutral point ungrounded, closing the low-voltage circuit side breaker before the high-voltage, which can effectively limit over-voltage in a safe range. The second harmonic characteristic of magnetizing waveform may disappear, while the intermittent angle characteristics are still significant. With the help of the intermittent angle principle, transformer differential protection may not misuse. The average time for each customer interruption is reduced from 40 minutes to 10 minutes and saves an hour for engineer on the way back and forth. It will greatly improve power supply reliability.


Author(s):  
Josifs Survilo ◽  
Antons Kutjuns

Operation Modes of HV/MV SubstationsA distribution network consists of high voltage grid, medium voltage grid, and low voltage grid. Medium voltage grid is connected to high voltage grid via substations with HV/MV transformers. The substation may contain one, mostly two but sometimes even more transformers. Out of reliability and expenditure considerations the two transformer option prevail over others mentioned. For two transformer substation, there may be made choice out of several operation modes: 1) two (small) transformers, with rated power each over 0.7 of maximum substation load, permanently in operation; 2) one (big) transformer, with rated power over maximum substation load, permanently in operation and small transformer in constant cold reserve; 3) big transformer in operation in cold season, small transformer-in warm one. Considering transformer load losses and no load losses and observing transformer loading factor β it can be said that the mode 1) is less advantageous. The least power losses has the mode 3). There may be singled out yet three extra modes of two transformer substations: 4) two big transformers in permanent operation; 5) one big transformer permanently in operation and one such transformer in cold reserve; 6) two small transformers in operation in cold season of the year, in warm season-one small transformer on duty. At present mostly two transformers of equal power each are installed on substations and in operation is one of them, hence extra mode 5). When one transformer becomes faulty, it can be changed for smaller one and the third operation mode can be practiced. Extra mode 4) is unpractical in all aspects. The mode 6) has greater losses than the mode 3) and is not considered in detail. To prove the advantage of the third mode in sense of power losses, the notion of effective utilization time of power losses was introduced and it was proven that relative value of this quantity diminishes with loading factor β. The use of advantageous substation option would make it possible to save notable amount of electrical energy but smaller transformer lifetime of this option must be taken into account as well.


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