This paper presents the design and implementation of a single-phase multifunctional electric-vehicle (EV) on-board charger with an advanced vehicle-to-vehicle (V2V) functionality for emergency roadside charging assistance situations. Using this function, an EV is able to charge from another EV in case of an emergency when the battery is flat and there is no access to a charging station. The designed EV charger can support the proposed V2V function with rated power and without the need for an additional portable charger. It can also provide conventional functions of vehicle-to-grid (V2G), grid-to-vehicle (G2V), the static synchronous compensators (STATCOM) and active power filter (APF) (i.e. reactive power support, and harmonics reduction). All the functions are addressed in the control part through the sharing of existing converters in an all-in-one system. The proposed EV charger is designed and simulated in MATLAB/Simulink, and a laboratory prototype is also implemented to validate its key functions.

This paper presents an enhanced current controller for improving the performance of a class of single-phase grid-connected inverters operating in weak and distorted grid conditions. An inverter designed to operate at normal (strong or stiff and clean) grid conditions may not perform satisfactorily during weak and distorted grid conditions. One major reason is the interfering dynamics of the synchronization or phase-locked loop (PLL). This paper proposes an enhanced control structure for a popular class of single-phase inverters to address this problem. The proposed idea is to include the PLL state variables into the main inverter controller thereby minimizing the undesirable interactions of the PLL with the other components. A method for optimally designing the controller gains is also proposed. Compared to the conventional one, the proposed controller is shown to have a more robust performance over a substantially wider range of weak and distorted grid conditions. Extensive simulation and experimental results are presented to validate the proposed controls.

This paper presents a fast and robust dc-bus voltage control method for single-phase grid-connected dc/ac converters. The proposed technique precisely estimates the double-frequency (2-f) ripple of a dc-bus voltage and removes it from the voltage-control loop without adding any additional dynamics or oscillations. Conventionally, the 2-f ripple is managed by using large capacitors which increase the cost and bulkiness of a converter. As a state-of-the-art approach, a notch filter (NF) or a dc-voltage estimator is used to effectively block the 2-f ripple from the voltage-control loop, which can significantly reduce the capacitor size. However, such an approach introduces new dynamics in the control loop, causes additional oscillations on the bus voltage and increases the settling time of its response. This limits the degrees of freedom of the design to improve the overall system damping. The proposed method in this paper has no adverse impact on the original bus-voltage dynamic response. As a result, the bus-voltage control can be designed with higher speed and robustness and the whole system can operate with a reduced transient at both the bus voltage and the output ac current. The proposed approach is thoroughly analyzed and its effectiveness is validated through simulations and experimental results.