High-frequency, three-phase current controller implementation in an FPGA

Abstract

Three phase rectifiers with switching frequencies of 500 kHz or more require high speed current controllers. At such high switching frequencies analog controllers as well as high speed DSP-systems have limited performance. In this paper, two high speed current controller implementations using two different FPGAs -one for switching frequencies up to 1 MHz and one for switching frequencies beyond 1 MHz -are presented to overcome this performance limitation. Starting with the digital system design all the blocks of the signal chain, containing A/D interface, digital controller implementation using HW-multipliers and implementation of a novel high speed, high resolution PWM are discussed and compared. Final measurements verify the performance of the controllers.

Code development of a DSP-FPGA based control platform for power electronics applications

“…The ADC conversions start in the center of every half switching rate of the PWM so the current measurements are taken in the average point and the measurements ringing is minimized [13]. As the duty cycles are also updated every half switching rate of the PWM the control system will have the double the bandwidth.…”