Grid current shaping of single phase diode rectifier with small DC-link capacitor for three phase motor drive

In this paper, motor drive system fed by single phase diode rectifier without Power Factor Correction (PFC) circuit is proposed. The motor drive considered in this paper consists of single phase diode rectifier, three-phase inverter, and small DC-link capacitor. Since DC-link capacitor is small, grid input current of the diode rectifier can be directly affected by electrical output power of the inverter. Using this aspect, the proposed method in this paper can drive the motor and shape the grid current with low harmonics simultaneously. This paper proposes the motor current reference generation method and the direct regulation method of the inverter output power by modifying the output voltage reference. Comparative analysis of Interior Permanent Magnet Synchronous Motor (IPMSM) and Synchronous Reluctance Motor (SynRM) with proposed drive system is also included. With the proposed controller, the harmonic components of the grid current can be suppressed below the limits stated in the regulation IEC61000-3-2. Also, cost and size of the inverter system can be significantly reduced by removing electrolytic capacitor and PFC circuit from the system. The improved performance of the proposed method was verified by the experimental results using the inverter system with a 5μF DC-link capacitor.