Transformer-Based Single-Phase AC–DC–AC Topology for Grid Issues Mitigation

Freitas, Nayara B. de; Jacobina, Cursino B.; Gehrke, Bruna S.; Cunha, Maxsuel Ferreira

doi:10.1109/tia.2019.2912547

Cited by 18 publications

(5 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In these applications, controlling the voltage and frequency is a compulsory requirement. The conventional way for achieving this is an indirect conversion of electrical power based on rectification of AC into DC by employing voltage-controlled or uncontrolled approaches and inverters to obtain regulated AC from DC power [5][6][7]. With an uncontrolled rectification scheme, the voltage of the DC-link capacitor may be made controllable by employing DC-to-DC voltage regulating systems [8].…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2022

View full text Add to dashboard Cite

Variable voltage and frequency are required to govern the torque-speed characteristics of many industrial drive systems. Traditionally, this is achieved with a power converting system implemented with multistage converters. This technology is based on rectifying AC power into DC and then DC into AC with an inverter circuit. The power quality concerns of both conversion stages are tackled by selecting high switching frequency PWM control and harmonics mitigation filters. Also, using a bulky DC-link capacitor is one of the big sources of low system reliability, so this approach increases the conversion losses, circuit, and control complications. The frequency step-down conversion is very attractive with direct AC-AC converters as it has a simple control and circuit structure, but these converters face poor power quality challenges once the output frequency is decreased with respect to an input. In these converters, the total harmonic distortion (THD) of the output voltage becomes very poor once the output frequency is reduced. The problem of high THD of the output is addressed in the power converting circuits implemented with line frequency multi-winding transformers. The required number of output winding and switching devices (diodes and thyristors) increases once the value of the output frequency is decreased. This will increase the overall volume, cost, and losses. The use of a bulky and costly line frequency transformer may be eliminated if AC voltage controllers have non-inverted and inverted voltage buck capabilities, such existing topologies either have complex control schemes or require a large number of operating devices. Therefore, in this research article, a new transformerless frequency step-down converter employing fewer devices is proposed. This approach is realized with a high-frequency controlled rectifier for the required voltage stabilization and a low-frequency inverter bridge for frequency control. Its validation is supported by the results attained from Simulink and practical-based prototypes.

show abstract

Section: Introductionmentioning

confidence: 99%

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

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Recently, single-phase AC-AC converters have been exploited widely among sensitive loads to compensate voltage sags and swells [1]. 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].…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2022

View full text Add to dashboard Cite

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.

show abstract

“…In order to avoid using an additional coupling transformer like in the FACTS-based regulators, AC-DC-AC based VSIs may be applied directly for voltage regulation for AC loads [9,10]. Another advantage of the mentioned VSIs is that they can regulate the voltages of each AC load through the distribution voltages, if the distribution voltage is in the determined level or not.…”

Section: Introductionmentioning

confidence: 99%

Three-phase Active Tracking AC-AC Voltage Regulator based on Buck Converter with an Efficient Hybrid Control Technique

Yalçın¹,

Himmelstoss

2022

Düzce Üniversitesi Bilim Ve Teknoloji Dergisi

View full text Add to dashboard Cite

This study proposes a switch-mode three-phase active tracking AC-AC voltage regulator based on the buck converter. The regulator topology incorporates a moderate number of components with less complexity and high efficiency. An efficient hybrid control technique, based on a closed-loop PID controller that is supported with a new designed feedforward controller, is proposed for the regulator control different to the similar studies in the literature. The hybrid control technique augments the response of active tracking of the reference output phase voltages to achieve an improved quality close to sine-wave output phase voltages for either the input AC phase voltages that are ideal pure sine-wave or include various harmonics. The regulator topology has a modular structure for independent control of each output phase. So, the regulator can help to achieve close to sine-wave output phase voltages to supply a balanced/unbalanced wye-connected three-phase load or independent single-phase loads. The presented three-phase regulator and the control technique are tested with simulation and experimental studies. The laboratory set-up of the regulator is designed for 2.2 kW output power, 0-300 Vp input phase voltages (50 Hz), and 0-200 Vp output phase voltages. The results demonstrated that the proposed switch-mode three-phase buck-type active tracking voltage regulator can provide the desired AC phase voltages with less than 5% THD (total harmonic distortion) and low harmonics for different operating conditions.

show abstract

Transformer-Based Single-Phase AC–DC–AC Topology for Grid Issues Mitigation

Cited by 18 publications

References 26 publications

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

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

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

Three-phase Active Tracking AC-AC Voltage Regulator based on Buck Converter with an Efficient Hybrid Control Technique

Contact Info

Product

Resources

About