Implementation of Snubber Circuits in a PV-Based Off-Grid Electric Vehicle Charging Station—Comparative Case Studies

Abstract

With the penetration of electric vehicles (EVs), there have been paradigm shifts in the transportation sector. EVs are ideally considered to be clean and eco-friendly, but they can overload the existing grid infrastructure and significantly contribute towards carbon emissions depending on the source of charging. The ideal solution is to develop a charging infrastructure for EVs that is integrated with solar energy technology. This paper presents the design of a zero-voltage switching snubber-based bidirectional converter for an off-grid charging station for EVs. The proposed system includes a solar array with a boost converter, a bidirectional converter with snubber circuits and an energy storage unit. A comprehensive comparison between various types of snubbers, such as the resistive capacitive diode snubber, active clamp snubber and flyback snubber, is presented. This type of system configuration clamps the rail voltage, due to the difference in current between leakage inductance and low voltage side-fed inductor currents, resulting in reduced current spikes at the converter’s switches. Such a converter, therefore, leads to higher efficiency of the charging station for EVs. The design of a snubber-based off-grid charging station for EVs is formulated and validated in the MATLAB/Simulink environment.

Design of a PV‐fed electric vehicle charging station with a combination of droop and master‐slave control strategy

“…The bidirectional converter (see Figure 5) provides the battery charging in buck mode and discharging operation in the boost mode, and provides power for the EV loads. 10,11 When the PV system's generated power exceeds the needed load power, the ESU's primary function is to charge the battery and discharge the battery when the generated power is inadequate to charge the EVs. The configuration of the isolated bidirectional converter with flyback and passive snubber circuit significantly lowers the influence of circulating current on the main switches, thus voltage spikes across the main switches are efficiently clamped.…”

“…When compared to a converter without snubber circuits, the efficiency of the converter with snubber circuits is superior. 10,11 The converter attains zero voltage switching conditions faster than a converter without the snubber. This design provides improved performance of the off-grid EVCS.…”

“…The ESU consists of a battery and an isolated bidirectional DC‐DC converter with a flyback and passive snubber circuit. The bidirectional converter (see Figure 5) provides the battery charging in buck mode and discharging operation in the boost mode, and provides power for the EV loads 10,11 …”

“…As a result, building stand-alone off-grid charging stations would be an ideal approach for promoting EV adoption globally while minimizing the impact on the current power grid. 10 In an earlier publication, 11 it has been shown that an off-grid EVCS using PV energy can be effectively installed in remote locations. The most common renewable sources of energy are solar and wind.…”

“…In an earlier publication, 11 it has been shown that an off‐grid EVCS using PV energy can be effectively installed in remote locations. The most common renewable sources of energy are solar and wind.…”