International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395 -0056
Volume: 04 Issue: 03 | Mar -2017
p-ISSN: 2395-0072
www.irjet.net
Simulation and Experimental Verification of Single-Phase PWM Boost Rectifier with Controlled Power factor M. A. Ahmed
Ass. Professor, Electrical Engineering Department, Aljouf faculty of Engineering, Aljouf University, Kingdom of Saudi Arabia ---------------------------------------------------------------------***---------------------------------------------------------------------
Abstract - In this paper, a single-phase PWM boost rectifier
operating at a controlled power factor has been simulated and implemented. The power circuit under investigation is a single-phase full bridge converter using IGBT transistors. The control algorithm provides the regulation of the output DC voltage as well as the control of supply current power factor. In addition, the proposed control strategy is implemented using a low-cost microcontroller Intel 80196. The experimental prototype offers several advantages such as; simplified control system, sinusoidal ac line current that satisfies the recently published harmonic current standard IEC 1000-3-2 Class D.
Fig -1: Harmonics spectrum of line current of diode rectifier compared to IEC standard.
Key Words: Single Phase PWM rectifier, Controlled power factor, Hysterisis current controller, DC voltage regulation
One problem associated with many existing drive systems with frequent regeneration is that the size of the dc link capacitor is often very large in order to limit the link voltage. Normally large capacitor bank of thousand micro-Farad is required, which increases the size, weight, and equipment cost. If braking resistor is used to dissipate the regenerative energy, the overall efficiency of the drive system becomes low [2-3]. The main features of PWM rectifier are: bi-directional power flow, nearly sinusoidal input current, regulation of input power factor to unity, low harmonic distortion of line current, adjustment and stabilization of DC link voltage, reduced capacitor due to bi-directional power flow [4-6].
1.INTRODUCTION As the amount of equipment using conventional diode rectifiers increases, harmonic input currents are becoming a problem. Harmonic current limits are recommended by the IEC standards (IEC 1000-3-2). In an effort to meet these requirements, power-factor correction techniques to reduce harmonic current are becoming very important. Furthermore, it is desirable to have minimal size, high efficiency, and low electromagnetic interference [1]. The main disadvantages of classical rectifiers are: i) They generate a lagging displacement factor with respect to the utility voltage. ii) Increased total harmonic distortion (THD) of ac supply current. These aspects have a negative influence on both power factor and power quality. The IEC 1000-3-2 International Standard establishes limits to all low power single-phase equipment having an input current with a ‘‘special wave shape’’ and an active input power P ≤ 600W. Figure 1 shows the harmonic spectrum of a line current drawn by classical diode rectifier compared to the IEC 1000-3-2 standards. It is noted that the diode rectifier is not able to comply with the standard, because of the input current is highly distorted, and has a very low power factor due to its large harmonic content. Many research efforts have focused on the control of the harmonic emission from power electronics circuits. Harmonic control techniques such as: passive filtering, active filtering, and power factor correction have been used.
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2. THEORY AND OPERATION The power circuit of the fully controlled single-phase PWM rectifier in bridge connection, show in figure 2, uses four IGBT switches to provide a controlled DC voltage Vo. In this topology, the output voltage Vo must be higher than the peak value of the source voltage υs in order to ensure proper control of the input current [7].
Fig -2: Single-phase PWM rectifier
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