Dual Active Bridge Converter for Bidirectional Power Control and minimization of Ripples in Inverter Stage

Abstract Solid-State Transformers (SSTs) play a crucial role in enhancing the performance of dual active bridge converters and ensuring robust isolation. These converters are renowned for their exceptional capability to efficiently handle high power levels. The H Bridge maintains a consistent 50% duty cycle to ensure operational control. The rectifying and inverter components within the SST DAB converter are interconnected in a multi-stage arrangement. Variations in output power result from the converter's direct current (DC) input and output voltages and the inverter's alternating current (AC) output. This type of converter exhibits noticeable second-order harmonics. The main goals of the control for the DAB converter are to maintain stability in both the power and the DC output voltage. Additionally, it aims to minimize disturbances originating from the inverter section as a secondary goal. The proportional-integral (PI) controller, and the proportional-integral (PI) controller in conjunction with a resonant controller are the two controller types examined in this work. Because of the DAB converter's low switching frequency, the typical PI controller only amplifies a limited amount at 120 Hz, which causes amplified voltage ripples at the inverter's output. One method to minimize these ripples is by enhancing the PI controller's Kp value, however doing so may cause the feedback loop to become unstable. It's important to note that a standalone The PI controller can effectively regulate the DC voltage. but it cannot entirely eliminate ripples. Alternative approaches such as resonant controllers can be employed to address this limitation. This technique may efficiently manage the output voltage and lessen ripples.