Small Signal Average Switch Modeling and Dual Loop Control of Bidirectional Integrated Converter for G2V and V2G Applications in Battery EVs

This paper proposes a small signal modeling approach of a bidirectional integrated converter configuration, which utilizes the traction inverter, motor windings and interleaved DC/DC converter for charging applications. This modeling technique represents the power electronic converters (AC/DC and DC/DC) as a transfer function that facilitates both Grid-to-Vehicle (G2V) and Vehicle-to-Grid (V2G) operations. During the G2V mode, the traction inverter converts into an AC/DC converter, while during the V2G mode, it operates as a DC/AC inverter, and the 3-phase interleaved DC/DC converter operates in buck and boost modes for the G2V and V2G operations, respectively. Moreover, the controller design based on the plant transfer functions is also a focal point of this paper. The inner current and outer voltage loop controllers of the DC/DC converter are designed based on the k-factor approach. For DC- link voltage control of the AC/DC converter, a dual loop control approach is adopted. Finally, the performance of both control systems has been validated via performance comparison between switch- based model and small-signal average system model in MATLAB/Simulink®.