Modeling and Analyzing of a New Simple Structure for DC-AC Converter Using Two Unidirectional Switches (original) (raw)
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IEEE Transactions on Power Electronics, 2016
This paper proposes a new type of ac-ac converter which can operate as traditional non-inverting buck and boost converters, and inverting buck-boost converter as well. The proposed converter uses six unidirectional current flowing and bidirectional voltage blocking switches, implemented by six reverse blocking IGBTs or series MOSFET-diode pairs, two input and output filter capacitors, and one inductor. It has no shoot-through problem of voltage source (or capacitor) even when all switches are turned-on and therefore; PWM dead times are not needed resulting in high quality waveforms, and solves the commutation problem without using bulky and lossy RC snubbers or dedicated soft-commutation strategies. It has smaller switching losses because; only two switches out of six are switched at high frequency during each half cycle of input voltage, and it can use power MOSFETs as body diode never conducts, making it immune from MOSFET failure risk which otherwise may occur due to poor reverse recovery problem of body diode. The non-inverting buck-boost mode of proposed converter can be used in applications with both step-up and step-down demand, while the inverting buck-boost mode can also be used in its application as DVR. Detailed analysis of the proposed converter is given, and experimental results are also provided.
A single-phase simplified DC-AC converter using DC-link capacitors and an H-bridge
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Two‐Phase Inverters with Minimum Switching Devices
Recent Developments on Power Inverters, 2017
The chapter deals with two-phase inverters with minimum switching devices whereby the main emphasis is devoted to 'minimum switches' converter topologies and control of passive load as well as split-single-phase induction motor. Such a converter consists of one-leg half-bridge matrix converter and the ac neutral point network as a new type of converter with two phase outputs loading the resistive-inductive or motoric loads. As harmonic content of the voltage of both phases gives very high value of total harmonic distortion (THD), roughly 86%, the current waveforms should be improved by using serial LC filter that brings much more suitable value of THD. Besides, the running capacitor creating needed phase shift (90) is electronically switched due to varied load. Analysis and modeling of such a new type of single-leg ac/ac converter with two phase outputs are done. The proposed topologies were simulated by Matlab/Simulink and verified in an LT spice environment. Worked-out simulation results are in good agreement with theoretical assumptions and make possible to give recommendation for the fair and right design of the chosen type of converter. Combination of mentioned measures brings a good quality of output quantities of converter and represents the main contribution of the chapter.
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A single-phase direct pulse width modulation (PWM) AC-AC converter is proposed in this paper. The proposed converter has a simple structure and efficient performance to be utilized as an AC voltage buck converter. It is designed with a low number of semiconductor switches and passive components (four switches, one inductor, and one capacitor). The major advantages of the proposed converter can be mentioned as: Only one switch operates during each mode of operation decreasing the circuit losses. It is operated with simple pulse width modulation control and doesn't require a safe-commutation strategy. It does not suffer from input source shoot-through and dead time problems. It retains the common sharing ground of the input and output and can be utilized for voltage sag and swell compensation. Additionally, the proposed converter features are high efficiency, continuous input and output currents, and low filtering requirements. The performance of the proposed circuit is extensively evaluated by using MATLAB/Simulink environment. Moreover, a DSP-based laboratory model is built for physical realization of the proposed converter operation.
Parallel of Two Unidirectional AC–DC–AC Three-Leg Converters to Improve Power Quality
IEEE Transactions on Power Electronics, 2018
A unidirectional single-phase ac-dc-ac converter is proposed and analyzed in this paper. It is composed of paralleled rectifiers and inverters sharing two legs with two dc-link capacitor voltages. Models and a control strategy of the systems including circulating currents are developed. Compared to the conventional four-leg and three-leg (4L and 3L) single-phase acdc-ac converters, the proposed topology allows the decreasing of the current and power ratings of the power switches, the harmonic distortion, and semiconductors power losses. And compared to the unidirectional three-leg ac-dc-ac converter, it allows to decrease the current and power ratings of the power switches and the harmonic distortion. In addition, a modified interleaved PWM (Pulse-Width Modulation) strategy using fourcarrier PWM is presented, ensuring five-level voltage at the input and output sides of the converter. Simulation and experimental results are also presented to demonstrate the viability of the proposed circuit.
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This paper proposes an ac-dc converter that gives multiple outputs capable of feeding both high and low power applications. The input ac supply is converted to dc by a diode bridge rectifier, filtered and fed to a modified multiport converter (MPC). This paper focuses on the design of the modified multiport converter that has a cascaded combination of zeta and a buck converter. This is designed as a single input and multiple output converter (SIMO) structure which can operate two loads, one with a high power and other with a low power application, depending on the time instant. The need for opting a multiport converter, reduces the number of switches utilized, thereby reducing the switching losses in the circuit. The zeta in the MPC boosts the input voltage and the buck converter reduces the input voltage and is accordingly fed to the need of the load. The design of the components have been analysed through steady state. MATLAB Simulink has been used to simulate the converter circui...
Improved Hybrid Converter with Simultaneous DC and AC Outputs
This Paper introduces new hybrid converter topologies which can supply simultaneously AC as well as DC from a single DC source. The new Hybrid Converter is derived from the single switch controlled Boost converter by replacing the controlled switch with voltage source inverter (VSI). This new hybrid converter has the advantages like reduced number of switches as compared with conventional design and provides DC as well as AC outputs with an increased reliability resulting from the inherent shoot through protection in the inverter stage. For controlling switches, PWM control based upon unipolar Sine-PWM is described. Simulink model is used to validate the operation of the converter. The proposed Converter can supply DC and AC loads at 220 V and 230V (rms) respectively from a 12V DC source.. A 50 W laboratory prototype is used to validate the operation of the converter.