A Novel Current Ripple Cancellation PWM for Isolated Three-phase Matrix DAB AC-DC Matrix Converter

The control method for an isolated three-phase matrix dual active bridge (DAB) AC to DC converter is proposed to control sinusoidal grid current waveforms with a minimum reactive current. The conventional SVM based on a constant current is not applied to the isolated three-phase matrix DAB AC to DC converter due to a high di/dt by employing a leakage inductance. Therefore, the duty calculation for the matrix converter is required to approximate the waveforms at a high-frequency transformer or implement a numerical calculation. However, the gird currents are distorted due to the error by such approximation. In addition, the numerical calculation is used as a complex implementation and requires a long calculation time. In this paper, the novel modulation method based on the current ripple cancelation is proposed for the isolated three-phase matrix DAB AC to DC converter. The high di/dt ripple current against current reference is canceled by the sum of the currents during the positive and negative half switching cycle without the leakage inductance value. The input and output dc current controls are achieved considering the effects of the leakage inductance. A continuous current mode (CCM) and discontinuous current mode (DCM) on buck and boost modes are clarified and confirmed by simulation. As the simulation results, the input current THD is reduced by 88.2% compared with the conventional method. As experimental results, the input current THD of 3.8% is achieved at rated power with CCM and DCM operation.