Solar Panel Converter Layout for Dual-Voltage EV Battery Charging
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Solution Overview
Problem
Existing solar energy systems for electric vehicles face inefficiencies in charging high voltage batteries from low voltage solar panels, particularly when energy needs to be transferred between different voltage networks, leading to additional losses and requiring complex control strategies.
Innovation Solution
An electric vehicle system comprising a low voltage (LV) battery, a high voltage (HV) battery, a series string of solar panels, and DC-to-DC converters, where DPP converters directly charge the LV battery and a string converter charges the HV battery, minimizing energy transfer between voltage networks and optimizing energy processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If energy is transferred from low voltage solar panels to high voltage battery through conventional DC-DC conversion, then the battery can be charged, but energy losses increase and system complexity increases
Solution Approach 1:
The system segments the charging function by using separate DPP converters for each solar panel rather than a single centralized DC-DC converter. Each converter independently manages power transfer from its associated panel to the battery, eliminating the need for complex voltage matching and reducing overall system complexity while minimizing energy losses through direct power processing.
Solution Approach 2:
The DPP converters dynamically adjust operating parameters (voltage, current) to match the instantaneous characteristics of both the solar panels and the battery. This real-time parameter adaptation enables efficient direct power transfer without conventional DC-DC conversion stages, reducing energy losses and simplifying the power electronics architecture.
2Ease of manufacture
If conventional DC-DC converters are used to charge the battery from solar panels, then voltage matching is achieved, but additional components are required and cost increases
Solution Approach 1:
The DPP converter is designed as a universal module that can directly interface with both solar panels and batteries without requiring additional voltage conversion stages. Each converter handles multiple functions (power conversion, voltage matching, current regulation) in a single integrated unit, reducing component count and manufacturing costs while maintaining flexibility for different panel and battery configurations.
3Loss of energy
If the LV battery is charged directly from solar panels, then charging efficiency improves, but voltage stability becomes challenging under unequal solar conditions
Solution Approach 1:
Each DPP converter is independently controlled to maintain optimal operating conditions for its associated solar panel and the battery. The converters locally adjust their conversion characteristics based on real-time panel output and battery state, ensuring voltage stability and maximum charging efficiency even when solar irradiance varies across different panels. This distributed control approach eliminates the need for complex centralized voltage regulation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration achieves an overall efficiency gain by directly charging the LV battery and allows for a stable constant voltage operation, reducing the need for additional components and enabling cost-effective charging even under unequal solar conditions, thus downsizing the LV battery.
Implementation Method 1
a series string of m > 1 solar panels PV1, PV2, ..., PVm adapted to receive solar radiation and convert the radiation to electrical energy
Data Source
Figure 1
AI summary
The present invention relates to an electric vehicle, comprising an LV battery, an HV battery, a series string of n > 1 solar panels, n DPP converters, and a string converter, wherein a positive input each DPP converter is connected to a positive output of a respective solar panel and a negative input is connected to a negative output of this solar panel, positive outputs of the DPP converters are connected to a positive pole of the LV battery, negative outputs of the DPP converters are connected to negative poles of both batteries, a positive input of the string converter is connected to a positive output of the series string and a negative input is connected to a reference potential, a positive output of the string converter is connected to the HV battery's positive pole, and a negative output of the string converter is connected to a reference potential.