Solar PV battery fed ev system with regenerative braking employing zeta converter
Overview of the MATLAB Model
The MATLAB model developed for this simulation consists of several key components:
PV Panel: The photovoltaic (PV) panel is the primary source of power in this system.
DC-DC Converter (Boost Converter): This converter is used to step up the voltage from the PV panel to a level suitable for the voltage source inverter.
Voltage Source Inverter (VSI): The inverter converts the DC voltage from the converter into AC voltage to drive the BLDC motor.
BLDC Motor: The Brushless DC (BLDC) motor is the driving force behind the EV.
Battery: The battery stores energy from both the PV panel and the regenerative braking process.
PV Panel Characteristics and Performance
The PV panel used in this simulation has the following specifications:
Rated Power: 334.9 Watts
Voltage at Maximum Power Point (MPP): 41.5V
Current at MPP: 8A
The PV and IV characteristics of the panel are analyzed under different irradiance levels with a constant temperature of 25°C. The duty cycle for the boost converter is generated based on the voltage, current, and MPPT (Maximum Power Point Tracking) algorithm, ensuring optimal power extraction from the PV panel.
Regenerative Braking System
Regenerative braking is a key feature in this EV system. The concept is simple: during braking, the kinetic energy of the vehicle, which would otherwise be lost as heat, is converted into electrical energy and stored in the battery.
Control Logic for Regenerative Braking
The control logic for regenerative braking is integrated into the system as follows:
Hall Sensor Output: The BLDC motor's hall sensor outputs are decoded to generate control signals.
Braking Command: When the braking command is activated, the system generates a pulse that controls the inverter to reverse the power flow, allowing energy to be fed back into the battery.
Simulation Results: Daytime Operation with Solar PV and Battery
In this scenario, the EV operates during the day, with both the solar PV panel and the battery supplying power to the BLDC motor. The simulation shows the following:
Initial Conditions: The irradiation is set to 1000 W/m², and the battery assists the PV panel in driving the motor.
Braking Event: After 5 seconds, the braking command is activated. The BLDC motor's speed decreases to zero, and the torque becomes negative, indicating regenerative braking.
Battery Charging: The regenerative energy slightly charges the battery, but due to the high power output from the PV panel, the effect is minimal.
Simulation Results: Nighttime Operation with Battery Alone
Here, the EV operates at night, with no power from the solar PV panel. The battery is the sole power source for the BLDC motor. The results include:
Initial Conditions: The irradiation is set to 10 W/m², effectively eliminating power generation from the PV panel.
Braking Event: After 5 seconds, the braking command is activated, and the regenerative energy is used to charge the battery.
Battery Charging: The battery shows a noticeable increase in charge due to the absence of solar power, making the regenerative braking more effective.
Conclusion
This MATLAB simulation demonstrates the integration of solar PV and battery systems in an EV, with a focus on the regenerative braking process. By efficiently harnessing the kinetic energy during braking, the system enhances the overall efficiency and extends the range of the electric vehicle.
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