Design for the interior permanent magnet synchronous motor drive system based on the Z-source inverter

Abstract

The permanent magnet synchronous motor (PMSM) running above the base speed requires flux-weakening control, which is usually realized by the direct-axis demagnetization current generated by the vector control, thus leading to a decrease in the system efficiency in the flux-weakening region. In addition, the motor power output range is limited by the inverter output voltage and current level. In this paper, a Z-Source drive PMSM control system with adjustable DC-link voltage was proposed to improve the efficiency of the motor system. The proposed system was experimentally verified. The response time of DC-link voltage is 10 ms and the overshoot is 3%, indicating good dynamic characteristics. Compared with the flux-weakening scheme, the Z-Source inverter scheme can achieve higher efficiency (about 3%) when the PMSM speed was set to 650 r/min.