Harmonic Mitigation Method for the DC-AC Converter in a Single Phase System

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INTERNATIONAL JOURNAL FOR TRENDS IN ENGINEERING & TECHNOLOGY VOLUME 5 ISSUE 2 – MAY 2015 - ISSN: 2349 - 9303

Harmonic Mitigation Method for the DC-AC Converter in a Single Phase System PrabhuPratap Singh.C.S

Lakhmanan.M

Anna University,Chennai, EEE csppsingh@yahoo.in

Anna University, Chennai, EEE lakshmanan.muthuramu@gmail.com

Abstract-This project suggest a sine-wave modulation technique is to achieve a low total harmonic distortion of BuckBoost converter connected to a changing polarity inverter in a system. The suggested technique improves the harmonic content of the output. In addition, a proportional-resonant Integral controller is used along with harmonic compensation techniques for eliminating the DC component in the system. Also, the performance of the Proposed controller is analyzed when it connecting to the converter. The design of Buck-Boost converter is fed by modulated sine wave Pulse width modulation technique are proposed to mitigate the low order harmonics and to control the output current. So, that the output complies within the standard limit without use of low pass filter. Keywords- DC-AC converter, PWM, Proportional Resonant controller, Injected harmonics, Fourier analysis

I Introduction The rapid development of renewable energies will increase the quality of power supplies, efficient and cheap in generation. Most of the renewable energies generate DC power, so there is in need of at least one inverter at the load side. Many commercial inverters are available in the market. Most of those inverters are use the variation of sine PWM full bridge inverter, because of simplicity in design. Additionally low pass filter isused at the load side to mitigate the harmonics content of the output. Although the main hurdles of this application are increased size, cost due to the filter and losses of the semiconductor switches performing the inverting operation at the inverter and converter. Several PWM methods are proposed to reduce the Harmonic content. Selective Harmonic elimination solves the transcendental equations characterizing the harmonics, So that appropriate switching angles are computed. Theoretically it was prove as satisfying Method. But quite difficult to do online and the solution these equations is computationally intensive.Other methods including the modification carrier signal or reference sine wave. All of them are open loop schemes and ignoring the existing harmonic content of the grid voltage or the distortion caused by the load. They can able to reduce harmonics in PWM itself and not at the terminal bus. Also, Sine wave modulated technique is used in converter cascaded inverter for improving the harmonic content when the supplied by an ideal constant DC source.

Fig.1 Converter topology

In this project, sine – wave modulation of the converter is improved to minimize the remaining output voltage of the capacitor when the inverter swaps polarity. Specific harmonics are injected in order to improve theharmonic content of the output. However, the injected harmonics are pre-calculated, according to the expected harmonic in the system created by PWM itself. In this paper, output harmonic is continuously monitored and mitigated. Computational power is consumed mostly for the measurement of the angle and magnitude of output harmonics rather than creation of cancellation of the harmonics. The main controller is PRI controller to mitigate any DC Offset in the control loop will propagate through the system. An integral controller is

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Harmonic Mitigation Method for the DC-AC Converter in a Single Phase System by International Journal for Trends in Engineering and Technology - Issuu