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In this paper, a simple modular passive ripple mirror circuit (PRMC) is adopted for eliminating the inherent high frequency current ripple of pulse-width modulated (PWM) DCDC converters. The PRMC doesn't require any additional active switches, driver circuits or any extra control; the cost can be saved easily. Only the reflected high frequency ripples are automatically induced and processed for proper...
Crystalline Si solar cell based on thin film transfer technique is low cost and high efficiency. Preparation of double layered porous Si is one of the methods to realize thin film transfer. Double layered porous Si was fabricated by a two-step anodic oxidation method in this paper. Si wafers were etched in the electrolyte solutions to form porous Si and annealed in H2 at 1000° for 1 h. The surface...
This paper presents a new topology for high power grid simulator, together with the corresponding control strategy and hardware parameters design methods. The grid simulator can provide three-phase sinusoidal voltage and generate typical grid fault situations like frequency deviations, unbalance and harmonic distortion which are common in the real world grid. In addition, a 2MW grid simulator was...
In Ethernet Ring network or fiber network, the NMS (Network Monitoring System) accurately distinguishes the fault point of the Optical Loss of Signal between fiber breaks and equipment faults. The method of using protection and restoration is another important matter which can effectively enhance the reliability of the Internet and lower the chances of disconnection. Although the protective function...
Concurrently, depending on increasing number of vehicles in cities, importance of incentive car-parks on peripheries, parking houses within shopping centres, airports, etc. constantly arises. At the same time, also demands on intelligent control such of these car-parks arise by reason of effective use of every parking spot. The proposed Parking Management Control System (PMCS) provides overview not...
The paper proposes a new active power conversion system (APCS) applied in microgrid for the connection and flexible power transmission between the main grid and the microgrid and power quality improvement. APCS is composed of three voltage sourced converters (VSCs), ie., main-grid VSC, shunt VSC, and series VSC, which all adopt modular multilevel converter (MMC) topology. The paper analyzes grid-connected...
A current mode switching regulator with optimized loop response, providing fast load transient response is proposed in this paper. Unlike conventional current mode control where the pole zero cancelation technique is used in the compensation design, the proposed system move the compensation zero to a higher frequency to achieve a higher loop gain in a fixed loop bandwidth. The higher loop gain can...
This paper analyzes different conduction modes of the conventional square wave controlled, three-phase six-switch converter instead of the common 180° or 120° mode. THD and harmonic components of these modes are presented. Study of voltage and switching device utilization are also included in this paper. Simulation results prove the validity of the theories. The research in this paper has some discrepancies...
A new dual chip GCT (Dual-GCT) structure with short transparent anode and corrugated p base region is presented based on a traditional Dual-GCT in this paper. The structural features and operation principle of the new device are analyzed, and the characteristics are studied by ISE simulator. Influences of high temperature on the characteristics are discussed. The research results that the new device...
The increase in size of large-scale photovoltaic plants increases the relative impact of ohmic losses in the dc and ac transmission. On the other hand, the amount of strings also increases, along with the number of combiner boxes and related equipment. This results in increased losses and costs that impose a limit to the competitiveness of PV technology for large power plants. PV plants today are...
In this paper, a digitally-controlled active EMI filter (DSP-AEF) is presented to solve noise reduction problems. Of course, it is possible to achieve noise reduction by use of passive filter elements; however, for a well-designed converter, by proper diagnosis of EMI noise, DSP active/passive combined (hybrid) filters can be used for this purpose. Thus, filter elements can be minimized, leading to...
This paper presents one dynamic regulation of controller parameters strategy for power factor correction (PFC) rectifier, which is based three-phase Vienna topology. To improve the converter power-density, the operation with high frequency and fast calculation is required. In this paper, the proposed controller is based on digitized feedforward compensation approach, can improve the control system...
Passivation is an effective way to reduce density of states (DOS) on the surface. In order to verify the differences and stabilities of H2S passivation on Si- and C-face of 6H-SiC, the adsorption of H2S on surface is studied by the first principles method, which is based on the density functional theory. Adsorption configuration and stability are researched with the coverage changing from 1/9monolayer...
A simplified Photo-Electro model of high power LED is proposed in this paper. Theoretical derivation of this model and optical experiments are introduced . The variables of this model are forward voltage U and forward current Id, which can be easily obtained and controlled in LED drivers. The validity of this model is verified through two kinds of typical LED chips and the model is helpful to the...
This paper proposes simple power line communication (PLC) method among DC-DC converters in DC distribution network system. In this method, current ripples in the converters' inputs are used as signal carrier whose frequency is modified as a function of information data. The modulator is easily realized by just adding a transistor and a resister to conventional PWM control circuit. Demodulator is also...
Alternative energy harvesting method gained considerable attention for solar power generator when solar energy was weak or absent. Continuous energy harvesting method was attempted using piezoelectric elements to supplement deficiency in micro scale solar generator system. Impact based piezoelectric generator has been studied as an enabling technology for high efficiency electricity generator, and...
An LED driver composed of a boost converter and dimmable current regulators with adaptive voltage feedback control (AVFC) is proposed. The AVFC is fulfilled with two diodes, one integrator, and one subtractor to sense the voltage variation among the current regulators and then to generate an adaptive reference voltage. According to the reference voltage, the output voltage of the boost converter is...
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