Vehicle Charging Circuit Voltage Division
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Solution Overview
Problem
Existing vehicle charging systems face high component costs due to the need for high nominal voltage components to match charging voltage with rechargeable battery voltage, particularly in high-power applications.
Innovation Solution
A vehicle charging circuit design that connects multiple rectifiers and DC-DC converters in series and parallel configurations, using a single-phase three-wire network to divide the operating voltage across multiple DC link capacitors, reducing the required nominal voltage of these components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high nominal voltage components are used to match charging voltage with rechargeable battery voltage, then high power requirements can be satisfied, but component costs increase significantly
Solution Approach 1:
The patent divides the high voltage system into multiple lower voltage segments. Specifically, it uses multiple DC-DC converters (first converter and second converter) each operating at lower nominal voltages (e.g., 400V) to collectively handle the high power charging task that would otherwise require expensive single high-voltage components (e.g., 800V). The converters are connected in parallel to share the power handling burden.
Solution Approach 2:
The patent combines multiple lower voltage conversion paths into a unified charging system. The first DC-DC converter and second DC-DC converter, along with their respective rectifiers and DC link capacitors, are merged into a single parallel architecture that collectively delivers high power to the rechargeable battery, achieving cost savings while maintaining high power capability.
2Ease of manufacture
If multiple rectifiers and converters are connected in series and parallel configurations, then the voltage burden on DC link capacitors is reduced, but device complexity increases
Solution Approach 1:
The patent segments the charging circuit into multiple independent but coordinated units: first rectifier + first DC-DC converter + first DC link capacitor, and second rectifier + second DC-DC converter + second DC link capacitor. Each unit operates semi-independently at lower voltage, simplifying component specifications and reducing costs compared to a single high-voltage unit.
Solution Approach 2:
Each rectifier-converter-capacitor combination is designed to perform multiple functions: rectifying AC voltage, converting DC voltage levels, and providing energy buffering. This multi-functionality at the module level allows the system to achieve high power capability through parallel combination of standardized modules, reducing overall system complexity despite the increased number of components.
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 design allows for cost-effective implementation by reducing the voltage burden on DC link capacitors, enabling efficient power supply to both the rechargeable battery and on-board electrical systems while maintaining high power capabilities.
Implementation Method 1
a plurality of rectifiers, and converters respectively connected downstream of the rectifiers, are connected to the same two potentials of the AC voltage connection
Implementation Method 2
converters each having a capacitor (a DC link capacitor), said capacitors being connected in series with one another by the rectifiers
Data Source
AI summary
A vehicle charging circuit includes an AC voltage connection that has a plurality of potentials, a switch device, a plurality of rectifiers that are each in the form of a bridge rectifier, a plurality of step-up converters, and a plurality of galvanically isolating DC-DC converters. Inputs of the rectifiers are connected to one other. The interconnected inputs of the rectifiers are connected to the AC voltage connection via the switch device. The rectifiers each have an output, downstream of each of which is connected one of the step-up converters. The step-up converters are connected to a rechargeable battery connection of the vehicle charging circuit.