Research on multi-module-cascaded high-power inverter digital modulation strategy and control method

Based on multi-module-cascaded inverter structure and optimized harmonic, this paper concludes the phase-shifting SPWM modulation topology applied to multi-module-cascaded inverter, proposes the phase-shifting SPWM modulation digital method based on digital signal processor (DSP) and complex programmable logic devices (CPLD), and solves the key problem of the triangle carrier phases exactly locked. The validity of the proposed method is verified through simulation and experiments. At the same time, a multiple-loop control scheme for single-phase high-power inverter is proposed. The proposed multiple-loop control scheme incorporates an inner current loop with an outer voltage loop. The corresponding control gains are designed through deadbeat theory so that the inverter can achieve fast dynamic response. A load disturbance compensation scheme has been proposed to improve the stiffness of the inverter. The validity of the proposed control scheme is verified through simulation and experiments.