Voltage Control Method with Non-linear Compensation and DC-Offset Elimination for One-leg T-type Dual Active Bridge Converter using Multi-Operation Mode

This paper proposes a voltage control method for one-leg T-type Dual Active Bridge (TDAB) converter in order to achieve a linearization of a current-control characteristic and an elimination of a dc offset in a inductor current at a transient state. In the conventional Dual Active Bridge (DAB) converter, the controller design is complicated due to the nonlinearity of the current-control characteristic and the dc offset of the inductor current at the phase-shift angle and the operation mode changing. In the proposed method, the nonlinearity of the current-control characteristic is compensated by the reverse system model including the inductance error. In addition, the dc offset of the inductor current is eliminated by updating the phase-shift angle and changing the operation mode at the peak or bottom of the base carrier. From experimental results, the ratio between the output current command and the actual output current agrees with the ratio between the nominal value and the error value of the inductance, i.e. the maximum error of 8.8%. Moreover, the dc offset of the inductor current is prevented when the phase-shift angle and the operation modes are changed.