Design and Implementation of Carrier Based Sinusoidal PWM (Bipolar) Inverter

SPWM or sinusoidal pulse width modulation is widely used in power electronics to digitize the power so that a sequence of voltage pulses can be generated by the on and off of the power switches. The pulse width modulation inverter has been the main choice in power electronic for decades, because of its circuit simplicity and rugged control scheme SPWM switching technique is commonly used in industrial applications SPWM techniques are characterized by constant amplitude pulses with different duty cycle for each period. The width of this pulses are modulated to obtain inverter output voltage control and to reduce its harmonic content. Sinusoidal pulse width modulation or SPWM is the mostly used method in motor control and inverter application. In this development a unipolar and bipolar SPWM voltage modulation type is selected because this method offers the advantage of effectively doubling the switching frequency of the inverter voltage, thus making the output filter smaller, cheaper and easier to implement. Conventionally, to generate this signal, triangle wave as a carrier signal is compared with the sinusoidal wave, whose frequency is the desired frequency. In this paper single-phase inverters and their operating principles are analyzed in detail. The concept of sinusoidal Pulse Width Modulation (PWM) for inverters is described with analyses extended to different kinds of SPWM strategies. Finally the simulation results for a single-phase inverter (Bipolar) using the SPWM strategies described are presented [1], [2], [5]. This project deals with implementing the basic theory of a Sinusoidal Pulse Width Modulated Inverter (SPWM) technique for Bipolar voltage switching, its Simulink modelling, estimating various designing parameters. The project will be commenced by a basic understanding of the circuitry of the SPWM Inverter, the components used in its design and the reason for choosing such components in this circuitry. After this, it will be attempted to simulate a model circuit on any simulating software e. g. MATLAB and analyse the output waveforms and also varying the modulation index (M) for both Simulink Model and Implemented Design of Bipolar voltage switching