A Transformerless AC-AC Converter with Improved Power Quality Employed to Step-Down Power Frequency at Output

Ashraf, Naveed; Abbas, Ghulam; Ullah, Nasim; Alahmadi, Ahmad Aziz; Yasin, Abdul Rehman; Awan, Ahmed Bilal; Jamil, Mohsin

doi:10.3390/en15020667

Cited by 6 publications

(3 citation statements)

References 28 publications

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“…In addition, there is no ability to regulate the output voltage, which is a mandatory requirement for industrial drive systems to avoid the core saturation of the AC motors. These problems are addressed in [34][35][36], but there is limited output voltage regulation for some output frequencies only. The solution proposed in these converters disturbs the power quality of the input current.…”

Section: Literature Reviewmentioning

confidence: 99%

A Single-Phase Compact-Sized Matrix Converter with Symmetrical Bipolar Buck and Boost Output Voltage Control

et al. 2022

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The development of single-phase symmetrical bipolar voltage gain matrix converters (MC) is growing rapidly as they find their application in power systems for dynamic restoration of line voltages, high voltage AC–DC converters, and variable frequency controllers for many industrial processes. However, the existing trend in matrix converter technology is a buck–boost operation that has inherently serious issues of high voltage and current surges or stresses. This is a big source of the high voltage and current rating of semiconductor switching devices. There is also a problem of high ripples both for voltage as well for current, requiring large size of filtering capacitors and inductors. The non-symmetrical control of the voltage gain increases the control complication. A large count of operating transistors is critical regarding their cost, size, and power conversion losses, as the space and cost required by their gate control circuits are much larger than the size and cost of the switching transistors. Thus, in this research work, a new single-phase MC is introduced only employing six fully controlled switching devices, ensuring similar operation or outputs as is obtained from the existing topologies that require the use of eight or more fully controlled switching devices, and the reduction by two or more switching transistors helps to compact the overall size and lower the overall cost. The separation in its voltage buck and boost operation enables smooth control of the voltage gain through duty cycle control. The low values of the voltage and current surges reduce the power rating and losses of the switching devices. The flow of the current in the filtering inductor is kept unidirectional to avoid the current interruption and reversal problem once the operation of the converter is abruptly switched from inverting to non-inverting and vice versa. All these factors are comprehensively detailed through the circuit’s description and comparative analysis. Simulation and practical results are presented to confirm the effectiveness of the developed circuit topology.

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Section: Literature Reviewmentioning

confidence: 99%

A Single-Phase Compact-Sized Matrix Converter with Symmetrical Bipolar Buck and Boost Output Voltage Control

et al. 2022

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“…Conventional indirect AC-AC converters, including two AC-DC and dc-ac conversions, have to employ expensive battery storage or super capacitors to supply compensating voltage [2][3][4]. Direct AC-AC converters usually cannot provide the voltage buck-boost possibility at the same time or suffer from the discontinuous input current and high current/voltage stress [5]. Likewise, matrix converters have limited voltage boost ability, which are not good choice for very high voltage drops compensation [6].…”

Section: Introductionmentioning

confidence: 99%

A Trans-Inverse Magnetic Coupling Single-Phase AC-AC Converter

et al. 2022

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This paper introduces a new single-phase AC-AC converter based on an impedance source circuit. Like the existing single-phase impedance source AC-AC converters, it has the buck-boost ability and direct ac conversion. The input and output voltage possesses the same ground, and the phase angle is maintained and reversed smoothly. The presented converter utilizes a coupled transformer which allows the designer to exploit the transformer’s turns ratio as a variable to attain the desired output voltage. Additionally, the used transformer provides an option to obtain higher voltage gain by decreasing the turns ratio. Hence, smaller size of the coupled inductors is required for the higher voltage cases. To eliminate the switching voltage and current spikes on the power switches, a safe commutation strategy is used instead of utilizing snubber circuits. Furthermore, the input current is continuous and sinusoidal with low harmonics thanks to embedding the input inductor in series with the input source. Additionally, a dynamic voltage restorer is presented based on the proposed converter to compensate the voltage sag and swell faults. Simulation results are provided to evaluate the theoretical analysis. Finally, a laboratory prototype has been fabricated to demonstrate the validation of the presented converter.

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“…The types that included simulation for each type separately and other studies [40][41][42]. Somewhat different, according to our estimation, as it makes the simulation a method for presenting the review in a form acceptable to researchers [43][44][45][46].…”

Section: Introductionmentioning

confidence: 99%

Simulation Model of Single-Phase AC-AC Converter by Using MATLAB

Shaker¹,

Shneen²,

Abdullah³

et al. 2022

Journal of Robotics and Control

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The current research sheds light on the electronic power devices that work as transformers and are named according to the function. A model of a single-phase transformer AC-AC type with half-wave and full-wave quality has been proposed. Its output is controlled by power, voltage and current, which is considered an input to the load. The fixed input transformer has a variable output according to the required power, voltage and current. Inverters of this type have so many uses that they are used in many different applications, including industrial, induction motor speed control, military, medical and household, including low-light circuits, among others. A simulation involving different types of single-phase AC transformers is proposed. The models were built in two ways, the first using a diode as an electronic switch, and the second using a thyristor. Different values for the load were chosen by adopting three values of 30 ohms, 40 ohms, and 50 ohms. An alternating power supply with an RMS value of 222 volts. Simulation was carried out after modeling to test the performance of the proposed transformer and its various modes of operation. Simulation models confirmed and reinforced the working theories of the proposed structures. From the results, we can reach the possibility of changing the voltage and power values using the electronic transformer by using the frequency of closing and opening the electronic keys within specific periods according to the proposed model, which can be represented or modified.

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A Transformerless AC-AC Converter with Improved Power Quality Employed to Step-Down Power Frequency at Output

Cited by 6 publications

References 28 publications

A Single-Phase Compact-Sized Matrix Converter with Symmetrical Bipolar Buck and Boost Output Voltage Control

A Single-Phase Compact-Sized Matrix Converter with Symmetrical Bipolar Buck and Boost Output Voltage Control

A Trans-Inverse Magnetic Coupling Single-Phase AC-AC Converter

Simulation Model of Single-Phase AC-AC Converter by Using MATLAB

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