Solar Panel Charging Layout for Dual EV Battery Voltages
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Solution Overview
Problem
Existing systems for charging electric vehicle batteries using solar panels are inefficient and costly, particularly when dealing with unequal solar energy conditions, and require additional components like DC-DC converters.
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 the converters are configured to directly charge the LV battery and the HV battery is charged via a string converter, minimizing energy transfer between batteries and reducing the need for additional components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a series string of solar panels is used to charge both LV and HV batteries, then charging capability is improved, but voltage matching complexity and energy loss increase
Solution Approach 1:
The patent divides the solar panel array into two separate parallel strings: one dedicated to charging the LV battery and another dedicated to charging the HV battery. This segmentation allows each string to be optimized for its specific battery's voltage requirements, eliminating the energy losses associated with voltage conversion and complex power electronics that would be needed in a series configuration.
Solution Approach 2:
The patent introduces separate DC-DC converters as intermediary devices for each solar panel string. These converters act as mediators that efficiently match the voltage output of each solar string to the specific voltage requirements of the LV and HV batteries, enabling direct charging without energy loss from complex voltage transformation.
2Productivity
If additional DC-DC converters are added to manage solar charging, then charging efficiency is improved, but system complexity and cost increase
Solution Approach 1:
The patent segments the power conversion function into two separate, simple DC-DC converters, each dedicated to one battery type. This segmentation avoids the need for a single complex multi-functional converter that would be required to handle both LV and HV batteries from a series solar array, thereby reducing overall system complexity while maintaining charging efficiency.
3Power
If solar panels directly charge the HV battery, then high voltage charging is achieved, but voltage mismatch under unequal solar conditions reduces reliability
Solution Approach 1:
The patent introduces a dedicated DC-DC converter as an intermediary between the solar panel string and the HV battery. This converter acts as a buffer that decouples the solar panels from the battery, allowing the system to maintain reliable charging even under unequal solar conditions by managing voltage mismatch within the converter rather than allowing it to affect battery charging directly.
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 higher efficiency and cost-effectiveness by stabilizing the LV battery voltage and reducing the size of the LV battery, while avoiding additional components, thus lowering overall costs and maintaining reliable charging under varying solar conditions.
Implementation Method 1
a series string of n > 1 solar panels PV1, PV2, . . . , PVn
Data Source
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.