DC-Link Current Minimization Control for Current Source Converter-Based Solid-State Transformer
- Georgia Inst. of Technology, Atlanta, GA (United States)
- Tesla, Palo Alto, CA (United States)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
This article proposes a fast predictive control method and a small DC-link inductor to minimize the DC-link current in current-source converter (CSC)-based solid-state transformer. The DC-link current minimization can significantly reduce power loss and improve efficiency. The challenge of this problem is on improving both steady-state and dynamic performance. PI control methods and large DC-link inductors are conventionally used in the CSC but have limited dynamic performance. A model predictive control (MPC) method is proposed to achieve switching-cycle-level settling time, and the DC-link inductor is sized for 40% ripple to enable fast current change. Importantly, this article also proposes to minimize the DC-link current by varying the current even within a line cycle under single-phase load to improve the steady-state performance, in contrast with the reduction to a constant value in the literature. The proposed MPC features a constant switching frequency without weighting factors. The MPC does not have a high computational burden and is implemented in a regular digital controller for a prototype of soft-switching solid-state transformer (S4T) with reduced conduction loss. The effectiveness of the proposed method has been experimentally verified on the SiC S4T prototype during steady-state and dynamics under different multiport power flow conditions up to 2 kV peak. Here, the DC-link current in the experiments is close to the minimum current with a short zero-vector duration, which further verifies the performance of the proposed method.
- Research Organization:
- Georgia Institute of Technology, Atlanta, GA (United States)
- Sponsoring Organization:
- USDOE Advanced Research Projects Agency - Energy (ARPA-E)
- Grant/Contract Number:
- AR0000899
- OSTI ID:
- 1892472
- Journal Information:
- IEEE Transactions on Power Electronics, Vol. 37, Issue 10; ISSN 0885-8993
- Publisher:
- IEEECopyright Statement
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
14 SOLAR ENERGY
17 WIND ENERGY
24 POWER TRANSMISSION AND DISTRIBUTION
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
42 ENGINEERING
solid-state transformer (SST)
three-port power electronic transformer (PET)
current-source inverter (CSI)
medium voltage (MV)
medium-frequency transformer (MFT)
variable DC link
efficiency improvement
loss reduction