A dsPIC based novel digital sinusoidal pulse-width modulation technique for voltage source inverter applications

• A novel digital SPWM technique is presented.
• Technique based on immediate calculation of duty cycles.
• Duty cycles calculation with fractional multiplication in dsPIC.
• Proposed technique solves the drawbacks of existing techniques.
• Algorithm developed for grid-connected applications.

This paper presents a novel digital sinusoidal pulse-width modulation (SPWM) technique based on immediate calculation of duty cycle count (DCC) values of pulses with high speed Harvard architecture based RISC controllers. The DCC values are calculated with the multiplication of an instant modulation index count (MIC) and a preloaded sine count value (SCV) table in the program memory of the controller. The proposed technique overcomes the drawbacks of overhead time in digital carrier-reference based technique and large memory requirement in look-up table technique. The proposed technique is effective where frequent change of modulation index (MI) of SPWM is essential like grid-connected inverter applications. The effectiveness of the proposed technique is verified with both Proteus VSM based simulation and dsPIC based experiment.