Characteristics of a proposed SVPWM strategy for delta inverter with DSP-based real-time implementation

This paper proposes and evaluates the performance of a new space vector pulse width modulation (SVPWM) technique for a reduced topology of a three-phase voltage source inverter namely delta inverter. According to the operation principle of the delta inverter, it is not possible to provide a zero-voltage vector. Therefore, unlike conventional SVPWM techniques that apply two active vectors and one zero-vector to synthesize the reference voltage vector, the proposed technique makes use at any switching period of the three available active vectors of the inverter's space vector diagram. Moreover, an appropriate switching sequence is introduced with the aim to create a virtual zero-vector from the application of the three available active vectors. New analytical expressions of the duty ratios that define the application times of each active vector are also developed in this work. The effectiveness of the proposed SVPWM technique was firstly proven through numerical simulations carried out on a delta inverter feeding a three-phase RL load. A comparative study with the existing modulation methods showed the superiority of the proposed SVPWM technique. The latter was also implemented in real-time on a digital signal processor and has been experimentally tested on a laboratory prototype of a delta inverter feeding an induction machine and an RL load. The obtained results confirmed its feasibility as well as its high performance.