Research On The Control Of Single Phase Cascade Inverter

Based on the modularized ASI, cascade inverter topology structure and modulation mode is introduced in this paper. Comparing with several control strategies such as single closed-loop feedback and dual close-loop instantaneous value feedback, the voltage-current dual closed-loop control strategy, which is the voltage effective value feedback and inductance current instantaneous value feedback, is adopted. The outer-loop adopting the voltage effective value feedback regulates voltage output and reduces the steady error of output voltage. The inner-loop control is inductance current feedback, which implements the stabilization of system, and limits the inductor current. This dual-loop strategy is analysed completly and simulated. The implementation strategy is using digital and analogous hybrid control. The voltage loop is realized by DSP, and the inner- loop is realized by analogous circuit The design of CPLD which simplified signal-phase cascade inverter circuit is also introduced in this paper. A cascade 6KVA experimental prototype is accomplished and validates its stabilization and external characteristic.