An application of a constrained adaptive lattice structure allpass-based notch filter for advanced control of surface-mounted permanent-magnet synchronous drives

A constrained adaptive lattice-structure allpass-based notch filter provide s minimal phase delay and complete attenuation of the notch frequency. The allpass sections of the filter are realized as structurally lossless bounde d real functions, with a minimum number of delay elements and multipliers, The filter structure admits orthogonal tuning of the notch frequency and no tch bandwidth. An improved control scheme for surface-mounted permanent-mag net synchronous (SMPMS) drives ensures stable high-performance operation in the flux weakening region, utilizing the over-modulation and six-step mode s of the space vector modulation (SVM), An automatic transition into the fl ux weakening region is achieved by controlling the reference voltage magnit ude, The fifth and seventh stator current harmonics of the fundamental freq uency, generated in the over-modulation and six-step modes, propagate throu gh the current control loops, resulting in the sixth harmonic in the refere nce voltage for the flux weakening loop and deteriorating drive performance . To properly filter the sixth harmonic over the extended speed range of th e drive, the constrained adaptive lattice-structure allpass-based notch fil ter is employed.