Implementation and Experimental Validation of a Real-Time PWM Algorithm based on B-Spline Carriers for Three Phase Voltage Source Inverters

This paper presents the implementation and experimental results of an algebraic real-time Sinusoidal Pulse Width Modulation algorithm (SPWM) based on B-Spline carriers. B-Spline functions are used as carrier signals with the aim to to reduce harmonic content of the three phase inverter output voltage. The presented algorithm eliminates the problem of B-Spline recursive evaluation with convolution integrals or convolution sums in digital counterpart. The pulse pattern synthesis is made with the help pre-calculated duty cycle expressions. In this way there is no real need to synthesize the carrier signal so the hardware and the whole inverter control system becomes cheaper, more reliable and affordable. The proposed implementation Algorithm effectiveness is finally verified by means of experimental tests in different operating condition (e.g. for different values of the amplitude modulation index and for different values of the power factor) of a three phase inverter.