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

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.