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The paper presents a new four-level voltage source converter (VSC). Compared to conventional four-level converters, this proposed converter has fewer components and can be used for a higher power density system in low and medium voltage applications. Its principles and advantages are studied in this paper. The effect of various redundant switching states on the voltages of flying capacitors is analyzed...
This paper proposes a transformer-less modular multilevel DC/DC converter. The proposed converter can be used to interconnect two HVDC systems with different dc voltage levels and realize bidirectional power flow. Based on the arm energy balance condition, the optimal design arming at minimum inner circulating current is presented. A power close-loop control method is adopted to regulate the converter...
A novel control strategy is proposed for a bidirectional multiport single phase two stage microinverter without electrolytic capacitor. The application of this converter is for power factor correction under non-linear grid tied load. The converter is composed of a triple active bridge series-resonant DC/DC converter cascaded with a voltage source inverter where a film capacitor is used in the DC-Link...
Due to the increasing demands of safe and efficient renewable energy systems, isolated DC-DC converters became widely used in this field as the essential power conversion blocks. At the same time, such converters are demanded for wide input voltage range and fault tolerance as desirable features. This paper proposes a isolated boost full bridge DC-DC converter which features wide input range and resilient...
Voltage Balance of the series-connected dc-link capacitors is the key problem of three-level diode-clamped converters. In this paper, an auxiliary voltage balance circuit (VBC) is presented to maintain the voltage balance of dc-link capacitors. The voltage balance circuit consists of a clamping capacitor and a current-limiting inductor. With the clamping capacitor, the voltage stresses of the auxiliary...
Among various converters, the LLC electric current resonant converter attracts attention because of high power density, low noise and high efficiency. However, this converter cannot apply the analysis of averaging method, and impossible to derivate the transfer function, so designing is difficult. In this study, we devised a method to derive a frequency response characteristic with a transfer function...
This work presents the design of an autonomous, cost-effective and efficient solar powered irrigation pump using a switched reluctance motor (SRM) drive. The proposed system utilizes a modified CSC (Canonical Switching Cell) converter for power optimization of photovoltaic (PV) array. The continuous inductor current mode (CICM) working of DC-DC converter significantly minimizes the stresses on its...
A modular multilevel converter (MMC) with traditional cascaded PI control structure suffers from poor steady state and dynamic performance. This is due to the limited harmonic rejection capability of PI controller thus failing to alleviate even order harmonics in circulating current and due to the slower outer average voltage control loop resulting in significant deviation in submodule capacitor voltages...
This paper proposes a digitally controlled bipolar converter for dc micro grids. The bipolar converter configuration is based on the combination of SEPIC and CUK converter with the modifications in both the converters. In the proposed bipolar converter, the equivalent series resistance (ESR) of the transfer floating capacitor is increased by inserting a series resistance in the both SEPIC and CUK...
This paper presents a CMOS circuit able to magnify the value of a reference bias current. The magnification factor can be programmed via a 10bit interface in the 1–1024 range. A time domain technique is used to compare a replica of the output current and a replica of the reference current. A negative feedback circuit minimizes the errors up to 1%.
A modified structure of operational transconductance amplifier (OTA) in CMOS 65-nm technology with signal-current enhancer and slew-rate (SR) helper is presented in this paper. The bias current is chosen to be lower than 0.1 μA to reduce the overdrive voltage requirement and thus make the amplifier survive under 0.7 V supply. An SR helper is also introduced to improve the transient performance. As...
Paper deals with LCLC converter with DC output. Both current and voltage sourced output rectifiers are considered. The performance investigation is focused on the nominal and overload operation conditions. Several differences are discovered during transient and steady — state analysis. Most significant is the existence of "zero-voltage interval" (ZVI) at the parallel resonant tank of the...
This paper introduces a novel battery cell balancing technique for portable applications, where multiple series connected lithium-ion battery cells are utilized. The equal discharge of the battery cells are achieved through a simple modification of a hybrid step-down dc-dc converter, where only an additional resonant inductor is required. Hybrid converters, combining switched-capacitor and inductor...
Single stage power factor corrected (SSPFC) AC-DC converters are popular in industrial applications such as telecom because they are cheaper and smaller than conventional two-stage converters. The intermediate DC bus voltage of these converters, however, varies significantly when used in universal voltage range applications. A new AC-DC SSPFC resonant converter that can be operated with universal...
In this paper, a predictive direct power control (P-DPC) strategy for a three level NPC rectifier under ideal grid voltage is proposed, discussed and applied. With the proposed P-DPC strategy, the control targets are the active power, the reactive power and the neutral potential voltage; neither hysteresis comparators nor switching table are needed; sinusoidal input current with low total harmonic...
This paper presents a comparison between two DC-voltage balancing strategies for cascaded star-connected multilevel STATCOM: zero-sequence voltage, and negative-sequence current control. Different levels of unbalance and grid strengths are considered. The impact of the control strategies on the convert ratings in terms of voltage and current requirements are compared and the operating range of the...
Innovative memristor-centered strategies to sense, store, and process information may be tested inexpensively and reliably exploiting the nonlinear dynamics of simple emulators based upon standard two-terminal devices from electrical circuit theory. Should a promising outcome emerge from the emulator-based tests, the novel strategies would be later implemented with memristor nanodevices. A wide variety...
Recently, the penetration of solar photovoltaic (PV) systems in Low Voltage (LV) distribution feeders has significantly increased and is expected to increase further in the coming years. Variability in solar PV output and high R/X ratio of LV distribution feeder results in voltage fluctuations. Local distribution companies (LDCs) rely on load tap changing transformers or feeder voltage regulators...
In this paper, a novel interleaved boost converter topology is introduced. The proposed converter is based on a combination of two types of voltage multiplier cells (VMC): Dickson and Cockroft-Walton (CW) voltage multiplier. Connecting VMCs to an interleaved boost stage yields many benefits, including smaller ripples on the input current, reduced voltage stress across switches and capacitors, and...
A CMOS Crystal Oscillator with automatic amplitude control (AAC) is presented which occupies low area and consumes lower current when compared to existing state of the art designs. Amplitude control loop based implementations of low frequency crystal oscillators usually achieve low-power operation at the expense of die area. The proposed design aims at reducing the overall area by replacing the bulky...
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