Power Quality Analysis of the Output Voltage of AC Voltage and Frequency Controllers Realized with Various Voltage Control Techniques

Ashraf, Naveed; Abbas, Ghulam; Abbassi, Rabeh; Jerbi, Houssem

doi:10.3390/app11020538

Cited by 15 publications

(9 citation statements)

References 35 publications

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“…The instantaneous form of this sort of output voltage waveform or pulses is mathematically described in Equations ( 5)- (9). The pulse selective or half-cycle mathematical approach reported in [15] is applied to compute the rms voltage and Fourier coefficients of Equation ( 10) for the output voltage waveform of Figure 7.…”

Section: Power Quality Analysis Of Output Voltagementioning

confidence: 99%

“…The turn-off process of these devices is obtained through the line commutation approach. Although these power converters have high power capabilities, in this process, dominant generated harmonics are low-frequency, as reported in [15]. The conversion losses of thyristors-based operating topologies are high as they have high internal resistance and voltage.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2022

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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.

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Section: Power Quality Analysis Of Output Voltagementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

et al. 2022

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“…These power conversion schemes are simple to implement but their PQ concerns are highly degraded as dominant generated harmonics are low frequency. The power quality analysis of the single-phase ac voltage controllers with integer cycle, phase angle, and PWM control is analytically detailed in [4]. Also, the power processing units realized through these approaches can only lower the output voltage.…”

Section: Introductionmentioning

confidence: 99%

An Improved Bipolar Voltage Boost AC Voltage Controller With Reduced Switching Transistors

et al. 2021

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Single-stage power conversion with simple circuit arrangement is one of the attractive features of direct bipolar voltage ac-ac converters. This increases their potency in various applications that require voltage and frequency regulation. The grid voltage compensators, direct variable speed ac-ac drives, and induction heating systems require inverting and non-inverting operation of the input voltage. Their size, cost, and circuit complexity directly depend on the number of switching transistors, as the operation of each transistor requires the use of one gate drive circuit (GDC) and one isolated dc power supply (IDCPS). The size and cost of GDC and IDCPS are much larger than that of switching transistors. The use of fewer switching transistors also ensures low conversion losses and simplifies the switching schemes. Therefore, this research proposes a new ac-ac converter that is realized as a bipolar boost ac voltage controller having a low count of switching transistors. The suggested topology also eliminates the shoot-through of the input source or output filtering capacitor. The characteristics of the proposed circuit are explored through simulation results obtained through the Simulink platform. The confirmation of the simulation results is validated through the laboratory prototype.INDEX TERMS AC converter, bipolar voltage, grid voltage compensator, induction heating system, shoot through.

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“…So, it gains more attention from the researchers and developers. Thyristor-based AC voltage controllers (on-off or phase-angle) have some potency for low power application as the generated harmonics are always low frequency and have very severe power quality-related issues [12]. AC voltage controller based on high-frequency pulse-width modulation (PWM) control can be employed to tackle the low power quality concerns but their voltage gain is low (less than one) with unipolar capabilities.…”

Section: Introductionmentioning

confidence: 99%

A New Dual Polarity Direct AC-AC Voltage Regulator Ensuring Voltage Step-Up and Step-Down Capabilities

et al. 2021

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The problem of voltage sag and swell is one of the major reasons for low-quality power in the distribution system. Normally, it results from the system’s faults, including line-to-ground and line-to-line, non-linear characteristics of loads and sources. Its effect is very serious for the critical loads as their performance is very sensitive to the variation in voltage. The stabilization of voltage is a mandatory requirement in such a situation. The correction of such problems requires the addition and subtraction of the voltage once the line voltage is decreased and increased. This behavior of the correcting voltage is ensured by the use of voltage controllers that can convert a constant input voltage into a non-inverted and inverted variable form. Their voltage gains depend on the depth level of the problem. The voltage buck and boost capabilities of the AC voltage stabilizers can tackle the problems having any depth level. The smartness of such a system depends on the number of electronic devices as they are the key elements in the power conversion system. Therefore, this research proposes a new AC voltage controller with fewer solid-state devices. Its overall impact is low volume and cost. The validation of the introduced approach is ensured with the help of simulation modeling and results gained from the practical setup.

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Power Quality Analysis of the Output Voltage of AC Voltage and Frequency Controllers Realized with Various Voltage Control Techniques

Cited by 15 publications

References 35 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

An Improved Bipolar Voltage Boost AC Voltage Controller With Reduced Switching Transistors

A New Dual Polarity Direct AC-AC Voltage Regulator Ensuring Voltage Step-Up and Step-Down Capabilities

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