Variable Isolation Charger for EVs
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Solution Overview
Problem
Chargers for electric vehicles experience inefficiencies when converting AC input voltage to DC charging voltage, particularly when dealing with varying input line voltages, resulting in reduced overall charging efficiency and increased component costs.
Innovation Solution
A universal charger design that includes a boost stage and an isolation buck stage with adjustable operational modes, controlled by a controller to optimize intermediate voltage scaling based on input line voltage, ensuring improved efficiency across a range of input voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed intermediate voltage is used in the boost stage for universal input charging, then the charger can accommodate varying input line voltages (120 Vac and 240 Vac), but the overall charging efficiency varies significantly depending on the actual input line voltage
Solution Approach 1:
The patent applies dynamics by making the intermediate voltage adjustable rather than fixed. The boost stage dynamically adapts its output voltage based on the detected input line voltage. When 120 Vac is detected, the intermediate voltage is set to a first level; when 240 Vac is detected, it is set to a second level. This dynamic adjustment optimizes the efficiency of subsequent conversion stages while maintaining universal input compatibility.
Solution Approach 2:
The patent changes the voltage parameter of the intermediate stage based on input conditions. By varying the intermediate voltage level according to the input line voltage detected, the system optimizes energy conversion efficiency. This parameter change approach allows the charger to adapt to different input voltages while maintaining high efficiency across both 120 Vac and 240 Vac inputs.
2Adaptability or versatility
If the intermediate voltage is increased to handle higher input voltages, then 240 Vac input can be processed, but the efficiency drops when charging from lower voltage (120 Vac) inputs
Solution Approach 1:
The system dynamically adjusts the intermediate voltage based on the input voltage detected. For 120 Vac input, a lower intermediate voltage is selected to maximize efficiency; for 240 Vac input, a higher intermediate voltage is selected. This dynamic selection prevents the efficiency loss that would occur with a fixed high intermediate voltage setting.
Solution Approach 2:
The patent changes the intermediate voltage parameter according to the input voltage level. This parameter adaptation ensures that the conversion ratio through the isolation stage is optimized for each input voltage, thereby maintaining high productivity and charging efficiency across the full input voltage range.
3Adaptability or versatility
If a single charger design is provided for universal installation, then both 120 Vac and 240 Vac inputs can be supported, but the efficiency varies between different input voltage scenarios
Solution Approach 1:
The universal charger incorporates dynamic voltage adjustment capability. The controller detects the input voltage and dynamically selects the appropriate intermediate voltage level, ensuring optimal efficiency for both 120 Vac and 240 Vac inputs while maintaining a single unified charger design.
Solution Approach 2:
The patent implements parameter changes by varying the intermediate voltage setting based on detected input voltage. This allows a single charger design to maintain high efficiency across different input voltage scenarios by adapting its operating parameters rather than requiring separate designs for different voltage inputs.
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
The solution enhances overall charging efficiency by adjusting intermediate voltages and scaling factors, leading to increased energy storage capacity and reduced power dissipation, which translates to lower costs and reduced cooling requirements.
Implementation Method 1
a boost stage converting the line voltage to an intermediate voltage
Implementation Method 2
an isolation buck stage both converting the intermediate voltage to a secondary voltage and converting the secondary voltage to a charging voltage applied to the ESS, the isolation buck stage removing a common mode current between the ESS and the boost stage
Data Source
AI summary
A method for charging an energy storage system (ESS) from an AC line voltage having differing input voltages (e.g., 120 Vac or 240 Vac), the method includes a) determining which of the AC line voltages is provided for charging the ESS as a charging AC voltage; b) boosting the charging AC voltage to an intermediate voltage responsive to the provided AC line voltage; c) scaling, responsive to the particular one of the AC line voltages, the intermediate voltage to a secondary voltage using a scaling factor; and d) converting the secondary voltage to a charging voltage applied to the ESS.