Analysis and Research of a Multiple-loop Control Strategy for Single-Phase UPS Inverters

This paper presents the analysis and research of a fully digital control design for a multiple-loop regulation of single-phase inverter. The digital control scheme incorporates an inner fast current loop with an outer slower voltage loop to eliminate the weakly dumped poles of the output LC filter. The inner current loop is added to improve the performance of transient response and decrease THD content. The output voltage and load current compensation are also added in the scheme to improve the performance and robust of system. The control system is implemented on DSP TMS320LF2407A. Both the simulation and experiment results show that the DSP-based multiple-loop controlled inverter can achieve excellent performance, and the multiple-loop control strategy is good for the control of inverter