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This letter introduces a novel type of non-Foster element using a microwave transversal-filter-based negative group delay (NGD) circuit that can exhibit unconditional stability. The proposed device is realized by a distributed amplifier, in which the NGD response is synthesized by adjusting the ratio of transconductance of transistors in each stage. On top of this, by properly amending the in-band...
This paper presents the application of a robust nonlinear optimal controller for regulating the active and reactive power in a grid-connected three-phase inverter, which includes an LCL filter to mitigate the total harmonic distortion. The optimal control law is derived from the Hamilton-Jacobi-Bellman equation for state-dependent coefficient factorized nonlinear systems. An integral control term...
This paper proposes a concept of two-terminal active capacitor implemented by power semiconductor switches and passive elements. The active capacitor has the same level of convenience as a passive one with two power terminals only. A control strategy that does not require any external feedback signal is proposed and a self-power scheme for gate drivers and the controller is applied to achieve the...
Input current of a Current Fed Switched Inverter (CFSI) contains the switching frequency component (75 kHz) and a second harmonic component of line frequency (100 Hz) apart from the DC part. In prior designs, the second harmonic component was suppressed by increasing the size of passive components (inductor or capacitor), which makes the inverter implementation bulky. This paper presents a control...
Further growth in renewable energy integration would be dependent on reliability and cost-effectiveness. These two factors can be achieved through power converter topologies that enable transformer-less connection of renewable energy based technology to the grid. This paper presents a three phase five level dual tapped inductor quasi impedance source (qZS)-nested neutral point clamped (NNPC) topology...
A capacitor voltage balancing method for a three phase modular multilevel DC-DC converter (MMDC) is proposed in the paper. The MMDC is derived from a three phase DAB and a modular multilevel converter (MMC) and inherits desirable features of both topologies. To guarantee stable operation of the MMDC, submodule (SM) capacitor voltages are required to be balanced. The proposed balancing method is to...
This paper proposes possibilities of Y-connected three-leg topologies, that are built from combinations of two-level and three-level legs (hybrid structures). Therefore, four topologies are studied and compared in aspects such as harmonic distortion of output voltages and rating of power switches. Additionally, semiconductor losses comparisons in different scenarios of load (either high current or...
This paper discusses a MHz isolated HV/LV DC-DC converter for automotive applications. The proposed circuit is constructed with a low cost structure by using multitransformer and Si-MOSFETs to achieve frequency multiplying. Three circuit configurations namely, cascaded-type, parallel-type and cascaded-parallel-type, are considered and discussed. Fundamental control and switching behaviors are explained...
Owing to economic aspects, Central inverter is the dominating candidate in large scale PV installations despite its lower energy harvest compared to other topologies like string inverters especially under partial shading conditions. In this paper a new voltage balancing topology is introduced to enable better energy yield from central inverters. The proposed topology is characterized by its fractional...
An isolated high-voltage high-frequency pulsed power converter for non-thermal plasma ozone generation is proposed in this paper. With an input of 500 VDC, the output pulsed voltage can reach −12 kV through the inductor-capacitor resonance together with a step-up transformer. The pulse duration is designed as 1.66 μs. An anti-series connected switch pair at the input terminal enables the energy stored...
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...
This paper proposes a single-stage high-power-factor asymmetrical half-bridge AC-DC converter for power factor correction. The proposed converter is developed by integrating an asymmetrical half-bridge DC-DC converter with a set of coupled inductors and a blocking diode to achieve the single-stage AC-DC conversion with the buck-boost type power factor correction. By using the coupled inductors, the...
This paper presents an AC-powered, boost-converter-based multi-segmented LED driver that maintains a high-power factor (PF) and accurate input current level, using a novel look-up table (LUT)-based digital control with background calibration and optimal switching mode selection schemes. The presented multi-segmented LED driver aims to reduce the costs of high-voltage capacitors and high-inductance...
This paper proposes a high efficient soft-switching multiple-input positive buck-boost converter. Multiple-input converters (MIC) use usually forward-conducting-bidirectional-blocking (FCBB) switches to control their input voltages and currents. However, these FCBB switches may decrease the overall system efficiency because of their switching losses. This paper applied a soft-switching method into...
An edge-resonant soft-switching time-sharing (TS) multiple-input (MI) dc-dc converter is introduced in this paper. The proposed converter can achieve high efficiency with zero-current switching (ZCS) and zero-voltage switching (ZVS). The zero-current switching (ZCS) can be realized on switch turned-on states, and the zero-voltage switching (ZVS) can be realized on switch turned-off states. In addition,...
This paper proposes a single-phase AC converter with an active power decoupling circuit operated in DCM (discontinuous current mode) for PV (photovoltaic) systems. The proposed converter consists of an H-bridge single-phase AC converter and a boost converter, and a compensation circuit employed with a small capacitor for the power ripple. In many active power decoupling topologies that have been studied,...
A novel modulation technique for single phase grid-tied inverter is proposed in this paper. In normal discontinuous current mode (DCM) operation, the output current becomes distorted due to the resonant between parasitic output capacitors of switching devices and inductor during zero current periods if no current control method is applied. This low frequency distortion can be improved in the boundary...
This paper presents a multilevel modular step-down DC-DC switched-capacitor converter that utilizes soft switching resonant operation. Previous versions of traditional multilevel modular switched-capacitor dc-dc converters (MMSCC) have a low switching device voltage rating. Moreover, capacitor voltage stress increases proportionally as the voltage conversion ratio increments. Significant advantage...
This paper investigates two five-level reduced hybrid inverters with split-wound coupled inductor and reduced number of components. The proposed inverters are composed of two legs, one of two levels and another of three-levels. Two types of three-level leg have been investigated: diode-clamped and flying capacitor. When compared with more conventional topologies consisting of two three-level legs,...
A design methodology is presented for a full-bridge Power Factor Corrector (PFC) converter with two control schemes: the well-known Continuous Current Mode (C.C.M) and Triangular Current Mode (T.C.M). The second one is an extension of the Discontinuous Current Mode (D.C.M). The converter is composed of one high frequency leg and one leg switching at the grid frequency and includes the EMC (common...
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