Design of a Three-Level APF Controller Based on Dual DSP

To improve the compensation performance of Active Power Filter (APF), this paper proposes a three-level APF controller based on dual DSP, which improves resource allocation. The main DSP is responsible for load current sampling, compensation current sampling, DC side voltage sampling, harmonic and reactive compensation current extraction, current tracking control calculation, PWM wave modulation, and other tasks, while the auxiliary DSP is responsible for sharing some operations and signal sampling, Including harmonic calculation, grid voltage sampling, touch screen display, power outage data storage, etc., communication between the two DSP is achieved through dual port random access memory RAM; More reasonable allocation of software tasks has improved the parallel computing ability of dual DSP. And it has been verified in a three-level APF prototype that it can achieve a switching frequency of 20 kHz, reduce the grid current distortion rate from 15 to 2%, and achieve a harmonic filtering rate of 86.7%, demonstrating good harmonic filtering ability.