Performance Analysis of the Zero-Voltage Vector Distribution in Three-Phase Four-Switch Converter Using a Space Vector Approach

The ac current ripple, the common voltage (CMV), and the current stress on the dc-link capacitor are defined as the critical performance indicators of the three-phase four-switch (TPFS) converter, and the effect of the zero-voltage vector distribution on these crucial indicators is investigated comprehensively in the proposed paper. A unified space vector modulation (SVM) approach, including the special pulsewidth-modulated (PWM) signal logic, is developed to facilitate the performance analysis of the zero-voltage vector distribution. Then, a novel approach based on the nonorthogonal stationary frame is proposed to facilitate the sector identification. Furthermore, because of the asymmetry of the harmonics of the three-phase output voltages, an overall current performance indicator, the total three-phase ac current ripple, is defined to assess the overall performance of the three-phase ac current. In addition, the dc-link capacitor current and CMV per sampling period are investigated; different ineffective duty ratio allocations result in the varied CMVs and capacitor currents. Moreover, due to the complexity of the Fourier analysis method, the root-mean-square (rms) values of the crucial indicators are adopted to evaluate the relative merits of various zero-voltage vector distributions. The proposed rms value equations are straightforward for the evaluation of the effect of the zero-voltage vector distribution on these crucial indicators. Experimental results confirm the accuracy and usefulness of the proposed performance analysis.