Sliding Mode Controller-Based Single-Stage Bridgeless Power Factor Correction Charger for Solar-Assisted Light Electric Vehicles with Enhanced Battery State-of-Charge

Abstract

The rapid growth of light electric vehicles (LEVs) has increased the demand for efficient battery charging systems capable of achieving faster charging while maintaining high power quality and converter efficiency. Conventional proportional–integral (PI) controller-based bridgeless power factor correction (PFC) chargers exhibit limited dynamic performance under varying photovoltaic (PV) generation, grid disturbances, and battery operating conditions, resulting in reduced charging efficiency and lower battery State-of-Charge (SOC). To overcome these limitations, this paper proposes a Sliding Mode Controller (SMC) for a single-stage bridgeless PFC charger integrated with a solar PV source and utility grid. The nonlinear SMC provides superior robustness against parameter uncertainties, rapid disturbance rejection, and accurate regulation of battery charging current, output voltage, and DC-link voltage. Furthermore, an Incremental Conductance maximum power point tracking algorithm continuously extracts the maximum available PV power under changing irradiance conditions. The complete charging system is developed in the MATLAB/Simulink environment and evaluated under identical operating conditions. Simulation results demonstrate that the proposed SMC significantly improves converter stability, minimizes charging current ripple, enhances renewable energy utilization, and achieves a substantially higher battery State-of-Charge within the same charging duration compared with the conventional PI controller. The proposed charging strategy therefore offers an efficient, reliable, and practical solution for next-generation renewable-energy-assisted light electric vehicle charging applications.

Introduction

This work proposes a Sliding Mode Controller (SMC)-based single-stage bridgeless Power Factor Correction (PFC) charger integrated with a solar photovoltaic (PV) source for Light Electric Vehicle (LEV) battery charging. The objective is to improve charging efficiency, converter stability, renewable energy utilization, and battery State-of-Charge (SOC) compared with conventional PI-controlled charging systems.

Introduction

The rapid growth of electric mobility has increased the demand for efficient battery charging systems for Light Electric Vehicles. Lithium-ion batteries are widely used due to their high energy density and long lifespan, but charging performance depends heavily on converter topology and control strategy.

Conventional chargers typically use two-stage AC–DC/DC–DC converters controlled by PI controllers. Although effective under steady-state conditions, they suffer from:

• Higher switching and conduction losses,
• Larger component count,
• Slower transient response,
• Reduced efficiency under nonlinear operating conditions.

Single-stage bridgeless PFC converters reduce losses and improve power factor, while integrating solar PV makes charging more sustainable. However, fluctuating solar irradiance, battery characteristics, and grid disturbances require a more robust control strategy.

The proposed solution replaces the conventional PI controller with a Sliding Mode Controller (SMC), while using an Incremental Conductance Maximum Power Point Tracking (IC-MPPT) algorithm to maximize PV energy extraction.

Literature Survey

Previous research has focused on:

• Single-stage bridgeless PFC converters for improved efficiency.
• PV-assisted EV charging systems.
• Transformerless and compact charger topologies.
• Renewable-grid coordinated charging.

Although these developments improved converter design and renewable integration, most relied on PI controllers, limiting performance under changing operating conditions.

Recent studies identified Sliding Mode Control (SMC) as an attractive nonlinear control technique due to:

• Fast dynamic response,
• Excellent disturbance rejection,
• Robustness to parameter variations,
• Accurate current tracking.

However, limited research has applied SMC to solar-assisted bridgeless PFC chargers with the objective of increasing battery SOC within the same charging duration, motivating this work.

Methodology

The proposed charging system consists of:

• Solar photovoltaic (PV) array,
• Incremental Conductance MPPT (IC-MPPT),
• Single-stage bridgeless PFC converter,
• Utility grid,
• Sliding Mode Controller (SMC),
• Lithium-ion battery.

The operating principle is:

• IC-MPPT continuously extracts maximum PV power.
• When PV power is insufficient, the utility grid supplements battery charging.
• The SMC continuously monitors:
  • Battery charging current,
  • Battery voltage,
  • DC-link voltage.
• Based on charging current error and its rate of change, the SMC generates high-speed switching signals for the converter.

Compared with the PI controller, the SMC:

• Quickly rejects disturbances caused by solar fluctuations, grid voltage changes, and battery parameter variations.
• Maintains charging current close to its reference value.
• Minimizes current ripple and overshoot.
• Improves DC-link voltage regulation.
• Reduces converter losses.
• Increases charging efficiency.

The battery SOC is enhanced because the SMC delivers a more stable charging current, allowing more energy to be stored during the same charging interval.

Simulation Results

The proposed charger was developed in MATLAB/Simulink and tested under several operating conditions.

The simulation model includes:

• PV array,
• IC-MPPT,
• Bridgeless PFC converter,
• Utility grid,
• Sliding Mode Controller,
• Lithium-ion battery.

The IC-MPPT successfully extracts maximum PV power under changing irradiance, while the SMC maintains stable converter operation and charging current.

Performance was evaluated under:

• Input voltage swell (90–130 V),
• Input voltage sag (130–90 V),
• Step increase in load current,
• Step decrease in load current,
• Sudden PV outage during dual-input charging.

In every case, the SMC:

• Maintained stable charging voltage and current.
• Exhibited fast settling with minimal overshoot.
• Quickly compensated for disturbances.
• Ensured uninterrupted battery charging by seamlessly coordinating PV and grid power.

Battery Charging Performance

A comparison between PI and SMC controllers shows:

PI Controller

• Slower transient response.
• Longer charging current settling time.
• Lower charging efficiency.
• Lower battery SOC within the same charging period.

Sliding Mode Controller

• Faster charging current regulation.
• Better DC-link voltage stability.
• Lower current ripple.
• Reduced converter losses.
• Higher energy transfer efficiency.
• Significantly higher battery State-of-Charge (SOC) within the same charging duration.

Conclusion

This paper presented a Sliding Mode Controller (SMC)-based single-stage bridgeless Power Factor Correction (PFC) charger integrated with a solar photovoltaic (PV) source for efficient charging of lithium-ion batteries in Light Electric Vehicles (LEVs). The proposed charging architecture combines an Incremental Conductance Maximum Power Point Tracking (IC-MPPT) algorithm with a robust nonlinear SMC to maximize photovoltaic power extraction while ensuring accurate regulation of battery charging current and DC-link voltage. Compared with the conventional PI-controlled charger, the proposed SMC demonstrated superior dynamic performance, rapid disturbance rejection capability, and improved converter stability under varying operating conditions. Simulation studies carried out in the MATLAB/Simulink environment verified that the proposed controller effectively reduced charging current ripple, improved voltage regulation, and enhanced renewable energy utilization. Most importantly, the improved control strategy enabled the battery to achieve a higher State-of-Charge (SOC) within the same charging duration, indicating faster and more efficient charging. The bridgeless converter topology also contributed to reduced conduction losses and improved overall conversion efficiency while maintaining satisfactory power quality. Therefore, the proposed SMC-based charging system provides a reliable and intelligent solution for next-generation renewable-energy-assisted electric vehicle charging infrastructure. Future work will focus on real-time hardware implementation, experimental validation, adaptive sliding mode control techniques, battery ageing analysis, and integration with smart grid and vehicle-to-grid (V2G) technologies to further enhance charging performance and system reliability.

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Copyright

Copyright © 2026 Dr. P. Sangeetha , Vookanti Deepak Reddy . This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.