High-Frequency Current Harmonic Analysis and Suppression in Dual Three-Phase PMSMs With Advanced Carrier Phase-Shift PWM
Boyuan Zheng, Jibin Zou, Yongxiang Xu, Guodong Yu, Lu Wang, Pericle Zanchetta
Abstract
Carrier frequency current harmonic peaks induced by pulsewidth modulation (PWM) in motion control systems will cause high-frequency torque ripple, efficiency decrease, and electromagnetic interference problems. It is proved in this article that carrier-frequency harmonic current components in dual three-phase permanent magnet synchronous motor (DTP-PMSM) systems exhibit a different distribution and are more severe compared to the three-phase ones due to the existence of the low-impedance harmonic subspace, thereby limiting the further application of DTP-PMSMs. To address this issue, this article proposes an advanced carrier phase-shift modulation strategy. First, by introducing a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">π</i> /2 phase shift between two PWM modules, the dominating first carrier frequency harmonic current components in <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> – <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> subspace are halved. The high-frequency torque ripple, located at second carrier frequency, is also suppressed. Periodic frequency modulation is utilized in the proposed strategy to further suppress the high-frequency harmonic current components in both <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">α</i> – <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">β</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> – <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> subspaces. The effectiveness of the proposed strategy is demonstrated theoretically and verified by simulation and experiments. DC-link current can also benefit from the proposed strategy. Compared with conventional space vector pulsewidth modulation (SVPWM) and random SVPWM, the proposed strategy has a better harmonic suppression effect without inducing distortion.