Design and FPGA Implementation of an Ultra-Low Latency Field-Oriented Control (FOC) System

Field-Oriented Control (FOC) is essential for the high-performance operation of multiphase synchronous motors, traditionally implemented on microcontrollers or Digital Signal Processors (DSPs). However, the sequential execution nature of these software-based platforms introduces inherent latency, limiting the dynamic response achievable in high-speed applications. This paper presents a fully parallel hardware architecture for an FOC drive system, described in VHDL and targeting a Xilinx Artix-7 FPGA (Digilent Basys3 board). Key Highlights of the Design & Verification: Comprehensive Signal Chain: The design covers the complete forward signal chain, including the Clarke and Park transforms, a CORDIC-based sine/cosine core, incremental-form fixed-point PI current controllers, the inverse Park transform, and Space Vector PWM (SVPWM) generation via the min-max (zero-sequence injection) method. Rigorous Testing Framework: Each of the six constituent modules, along with the partial and full closed-loop signal chain, was verified using self-checking testbenches executed in GHDL. The verification process totaled 117 individual test checks, all of which successfully passed. Practical Troubleshooting: The paper documents the diagnosis and resolution of three critical functional issues that surfaced during verification: a fixed-point overflow at a CORDIC boundary condition, a mis-derived rescaling constant in the Park transform, and a simultaneous-event race condition in a testbench. The results establish the functional correctness of the complete control chain in simulation. Synthesis, timing closure on the target Artix-7 device, and closed-loop validation against a dynamic motor plant model are identified as the next phase of this work.