Performance and accuracy comparison of fixed and floating-point realizations of the Active Power Filter control algorithm

The comparison of performance and accuracy of the Active Power Filter control algorithm realizations has been presented in the paper. The worked out algorithms are based on dq synchronous frame control strategy. The following Texas Instruments digital signal controllers were used for the realization: fixed-point TMS320F2812 and floating-point TMS320F28335. The TMS320F28335 digital signal controller is the first floating-point controller in the C2000 family. It combines flexible control-specific interfaces and ease of use of an industrial microcontroller (MCU) with the processing power of DSP technology (up to 300 MFLOPS). Using of the floating-point digital signal processor allows improving accuracy of the computation, particularly in digital filtering (IIR low-pass filter) which has a direct influence on the quality of the generated current waveforms. The worked out algorithms have been practically verified on APF prototype which was built in the Institute of Industrial Electrical Engineering and Computer Science. The presented problems have been illustrated by laboratory results.