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Development of high frequency power electronic devices leads to high performance and flexible switch mode AC voltage stabilizers instead of traditional electromechanical types. This paper introduces a novel double stage topology for switch mode AC voltage regulators. The system produces a continuous adjustable isolated AC voltage providing a constant output voltage for sensitive loads. In order to...
A new control algorithm for AC/AC Modular-Multilevel Converter (MMLC) is introduced. This new control algorithm stands out due to its real-time operation and usage of all possible switching states in an MMLC. Independent control of output AC voltage with respect to the input AC voltage or load current is the second feature of the proposed algorithm. This control algorithm is well suited for balancing...
The concept of Dynamic Capacitor or D-CAP has been previously introduced by the authors. D-CAP is able to provide dynamic VAR and harmonic compensation in one single integrated unit. The topology is based on an AC chopper with the control based on the novel concept of virtual quadrature sources, where energy is exchanged between virtual sources at different frequency, instead of between DC and AC...
An AC voltage regulator based on a tapped transformer is presented in this paper, but do not considers SCRs as switching devices, the system offers a fast response under input voltage variations. An AC voltage regulator can be made with a transformer tap changer or with an AC-AC converter based on buck or buck-boost topologies. The first one is simple but with slow response traditionally and the others...
Now the voltage regulator usually has big bulk and high switch voltage stress. A new type of AC-AC direct converter with a small bulk is researched. To be used in high voltage and heavy load situation, isolated Cuk three-level converter is proposed. It is the cascaded type of isolated Cuk AC-AC converter using AC switch units. Besides, the operating principle and the control strategy are investigated...
This work presents a three-phase AC-AC converter, with independent phase control, based on matrix-converter structure. This converter is applied to electrical energy saving on the public lighting systems by means of regulation and control of the voltage applied to the lamps. The developed converter represents a technological improvement with respect to the traditional systems based on an autotransformer:...
Multilevel converters can reach medium-voltage operation, increasing the efficiency in high power applications. Among the existing multilevel converter topologies, modular multilevel converter provides the advantages of high modularity, availability and high power quality. Moreover, the main advantage compared to cascaded multilevel converters is the absence of input transformer; reducing the size,...
AC choppers are a family of ac-to-ac power converters that can be derived from the traditional dc-to-dc converters. Research activity in this kind of converter has recently increased in applications for power conditioning-such as voltage control in the distribution system and power flow control in the transmission system-as an alternative for the dc-link approach compensators based on voltage source...
The paper proposes a novel single-phase ac-ac converter topology based on Z-source concept. It could provide buck-boost function and make the role of frequency changer. Compared to the traditional ac-dc-ac converter, it uses less devices and realizes direct ac-ac power conversion, has simple circuit structure, so as to have higher efficiency and better circuit characteristics. Compared to the traditional...
A new AC-DC-AC matrix converter topology based on Cuk is proposed. The basic configuration of the new topology and its fundamental principle are firstly introduced, the analytic expression on the function of voltage transfer ratio and duty cycle is analyzed, and the rationale of double-loop control strategy is clarified. Finally the validity and feasibility of the new topology are tested by means...
This paper proposes a new type of three-phase AC-AC Z-Source converters which are derived from matrix converter (MC) theories. The proposed converters are capable of three-phase AC-AC power conversion and, except for exhibiting the input characteristics of MC: controllable (unity, leading and lagging) input power factor, it does overcome the two main drawbacks of MC: limited voltage transfer ratio...
This paper proposes a new class of matrix converters (MCs) referred to as AC chopper matrix converters (ACCMCs). They are AC-DC-AC MCs, of which rectifier stages are 3/2 phase MCs, and inverter stages are DC-AC inverters based on AC chop principle. The main attribute of the new MC topologies are the fact that it generates high voltage transfer ratio, depending on the instantaneous duty cycles. This...
This paper deals with a new topology based on single-phase Z-source AC/AC converter for voltage swells or sags compensation. The proposed system is able to compensate voltage swells. In addition, it is also able to compensate up to over 50% voltage sag. A commutation strategy to drive the AC/AC converter is employed to realize snubberless operation. Analysis is presented; Simulation and experimental...
Three-level (TL) switch unit is produced by two-level switch unit connected together in series manner. Combination mode TL AC-AC converter is proposed. The principle is investigated. In order to keep the balance of the claming capacitor voltages, mixed staggered complemented control strategy is proposed. Transient voltage feedback control strategy is taken in the proposed converter and principle diagram...
This paper deals with a new topology for three-phase ac-ac Z-source converter. Unlike other configurations, the proposed three-phase ac-ac Z-source converter has the capability to achieve maximum boot voltage ratio about 2. Injected capacitors are used to transfer energy to Z-source inductors in shoot-through state. Thus, the maximum output voltage gain can obtain. By controlling the duty cycle, the...
This paper investigates six three-leg single-phase to single-phase dc-link converters employing three-level and two-level legs. The pulse-width modulation techniques and a control technique that aims at maximizing the utilization of the DC-link voltage are presented. In addition, several relevant characteristics of the converter are addressed, such as voltage capability, harmonic distortion, shared-leg...
This paper proposes a new type of voltage swell/sag compensator based on single-phase Z-source AC/AC converter. The proposed topology employs a pulse width modulation (PWM) Z-source AC/AC converter along with a transformer. A commutation strategy to drive the AC/AC converter is employed to realize snubberless operation. Circuit analysis is provided. Simulation and experimental results at 20% voltage...
This paper deals with a new family of single-phase AC/AC buck-boost converter based on single-phase matrix topology. The proposed converter provides a wider range of output AC voltage in which the output voltage can be bucked and in-phase/out-of-phase with the input voltage; and the output voltage can be boosted and in-phase/out-of-phase with the input voltage. A commutation strategy is employed to...
Mainly due to historical and convenience reasons, for power levels up to several kVA electric utilities provide power distribution typically uses 1-phase a.c. feeders, despite a 3-phase supply would be technically preferable permitting for instance to use more efficient and compact induction motors, 3-phase rectifiers providing lower output ripple etc. This paper deals with a simple converter able...
Novel AC/AC converters with high frequency ac link are composed of two kinds of AC/AC converters, which are voltage mode based on Forward converter and current mode based on Flyback converter. The circuit configuration and topology, control strategy, principle characteristics, design criteria of the key circuit parameters, and principle prototype of two-kinds converters are deeply and comparatively...
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