Experimental result of multirate deadbeat control for PWM inverter using FPGA based hardware controller

A new approach for real time digital feedback control of PWM inverter is proposed, in which a deadbeat control combined with the multirate sampling method is realized using FGPA based hardware controller. The capacity of the output LC filter component occupies ineligible area for the cost performance of the inverter system for the UPS applications. If the capacity of the output LC filter is too small, the output voltage waveforms tends to oscillate between the sampling period when the deadbeat control is applied to the inverter system. In this paper, a novel approach to solve such phenomenon is proposed, which is the deadbeat control method combined with the multirate deadbeat control using FPGA based hardware controller. Deadbeat control ensures the state variables matches at each sampling instant for every sampling period. Also it is reported that the multirate deadbeat control minimizes the tracking error for the reference value. Adopting the multirate deadbeat control, the sampling frequency of the inverter becomes half of the carrier frequency, and it is suitable to implement for higher carrier frequency. Also the FPGA based control hardware enables to realize almost ideal real time feedback controller because of its capability to realize very fast calculation of the control method within a few /spl mu/ second. Design concept and hardware implementation of the FPGA based hardware controller for the PWM inverter is proposed. From the view point of UPS applications, the advantages and the disadvantages are discussed though simulations and experiments, the superiority of the proposed control law is verified.