*4.2. Experiment*

In order to validate the effectiveness of the proposed control strategy in a real system, an AC–DC MC prototype was constructed with six bidirectional switches, which are built by two insulated-gate bipolar transistors (IGBTs) modules (IXA37IF1200HJ), connected in series with a common emitter to validate the effectiveness of the proposed VSVM. The proposed strategy is performed by a Texas Instrument digital signal processor board (TI TMS320F28335). The parameters of the experiment are the same as in Table 1. Figure 15 shows the comparison of A-phase current, A-phase voltage, battery voltage, and DC current at 5 A. It can be seen that the proposed VSVM control strategy effectively reduces the DC current ripple of AC–DC MC compared with the C-SVM strategy in the range of high-modulation operation. The THDs of A-phase source current of both the C-SVM and the proposed VSVM methods are shown in Figure 16. The THD of the proposed VSVM method is slightly higher than the THD of the C-SVM method, this is a trade-off between ripple reduction and increasing current distortion.

The experimental waveforms of A-phase source current, A-phase source voltage, battery voltage, and DC current reference at 2 A of AC–DC MC under the C-SVM strategy and the proposed VSVM strategy are illustrated in Figure 17. Applying the optimized switching patterns for zero vector at low-modulation operation, the DC current ripple of the proposed VSVM is further reduced

while maintaining the performance of AC–DC MC compared with the C-SVM. The transient state performances of AC–DC MC under the C-SVM and the proposed VSVM methods are illustrated in Figure 18. The proposed method successfully reduces the DC current ripple at both high and low power range compared with the C-SVM method. The experimental results show the effectiveness of the proposed method in the reduction of DC current ripple compared with the conventional methods in the whole range of operation. The assessment of the proposed VSVM method compared with the conventional methods in terms of the reduction of DC current ripples and the increase in the THD values of the input currents is shown in Table 2.

**Figure 15.** A-phase current, A-phase voltage, battery voltage, and DC current under different modulation strategies for AC–DC matrix converter at high-modulation operation. (**a**) C-SVM; (**b**) Proposed VSVM.

**Figure 16.** THD of A-phase source current under different modulation strategies for AC–DC matrix converter at high-modulation operation. (**a**) C-SVM; (**b**) Proposed VSVM.

**Figure 17.** A-phase currents, A-phase voltage, battery voltage, and DC current under different modulation strategies for AC–DC matrix converter at low-modulation operation. (**a**) C-SVM; (**b**) Proposed VSVM.

**Figure 18.** A-phase currents, A-phase voltage, battery voltage, and DC current under different modulation strategies for AC–DC matrix converter at transient state operation. (**a**) C-SVM; (**b**) Proposed VSVM.


**Table 2.** Percentage comparison of reducing DC current ripple and increasing THD value of the proposed method compared with the conventional methods.
