1. Control Design of a 99% Efficiency Transformerless EV Charger Providing Standardized Grid Services
- Author
-
Michael Eull, Liwei Zhou, Weizhong Wang, Matthias Preindl, and Matthew Jahnes
- Subjects
business.product_category ,business.industry ,Computer science ,Electrical engineering ,Battery (vacuum tube) ,Grid ,AC/AC converter ,Power (physics) ,law.invention ,law ,Electric vehicle ,Energy transformation ,Common-mode signal ,Electrical and Electronic Engineering ,business ,Transformer - Abstract
A non-isolated fast charger is proposed for electric vehicle (EV) battery system. The leakage current can be reduced by the novel charging system without bulky transformer. A zero sequence voltage control method is developed to stabilize the common mode voltage thus reduce the leakage current. The proposed fast charger includes two energy conversion stages: DC/DC converter for battery side control; DC/AC converter for grid interface and common mode voltage control. The parameters of the system with LCL filter are analyzed and optimized for a better performance of grid interface. Grid service functions are designed for the fast charger to provide grid voltage/frequency compensations. High power (22kW) and high efficiency 99% are achieved with low leakage current 20mA. The experiments are implemented to verify the proposed fast charger system.
- Published
- 2022