Current Measurement Error Compensation Based on Modified Multiple Complex-Coefficient Filters in PMSM Drives

Current measurement errors (CMEs) including offset and gain errors can lead to the first- and second-order harmonics in dq-axes currents of permanent magnet synchronous machine (PMSM) drives. The thermal drift-caused CME can change during the operation of the PMSM, which should be compensated online. This article proposed a CME online compensation strategy based on a modified multiple complex-coefficient filter (MCCF). This compensator has two improvements based on MCCF. First, the reference model of PMSM is employed to replace the original CCF to achieve fast fundamental current feedforward, which effectively suppresses the additional disturbance caused by working condition variation. In addition, the gain error coefficient is directly compensated instead of the negative sequence current to further improve the adaptability of variable operating conditions. Compared with MCCF, the proposed strategies can greatly expand the practical application under variable conditions. The effectiveness of the proposed method is verified by simulation and experiment.