Reconfigurable DC-DC Converter for Wide-Voltage EV Charging
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Solution Overview
Problem
The availability of cost-effective electric vehicle service equipment (EVSE) such as DC-connected charging stations is limited, hindering the reduction of greenhouse gas emissions from the transportation sector, and existing on-board chargers (OBCs) face inefficiencies due to wide input and output voltage variations across North America, particularly for medium- and heavy-duty vehicles requiring high-voltage charging.
Innovation Solution
A DC-DC power converter with a reconfigurable transformer and secondary circuit branches, capable of switching between full and half-bridge modes, to adapt to varying input and output voltages, and a primary circuit with capacitors and switches to manage voltage levels, ensuring efficient power conversion across different grid voltage ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed bridge configuration (full or half) is used in the DC-DC power converter, then the circuit structure is simple, but the converter cannot adapt to wide voltage swings between 200V and 1000V input voltages and 400V to 1500V output voltages
Solution Approach 1:
The patent implements a reconfigurable bridge circuit that can dynamically switch between full-bridge and half-bridge configurations based on the input voltage level. When input voltage is high (above threshold), the circuit operates in half-bridge mode; when input voltage is low (below threshold), it switches to full-bridge mode. This dynamic reconfiguration allows the converter to adapt to wide voltage swings while maintaining efficient operation across different voltage conditions.
2Productivity
If DC-connected charging stations are deployed to enable efficient charging, then charging efficiency improves, but infrastructure costs and grid instability risks increase
Solution Approach 1:
The patent enables electric vehicles to perform self-service charging through on-board chargers that incorporate the reconfigurable DC-DC power converter. This eliminates the need for expensive external DC-connected charging station infrastructure by providing efficient charging capability directly in the vehicle. The converter's ability to adapt to wide voltage ranges allows it to work with various grid voltage conditions without requiring specialized infrastructure.
3Power
If on-board chargers are designed for high-voltage operation to support medium- and heavy-duty vehicles, then power capability increases, but efficiency decreases due to wide voltage variations
Solution Approach 1:
The patent changes the operational parameters of the power converter by dynamically adjusting the bridge configuration based on voltage levels. The control system monitors input voltage and switches between full-bridge and half-bridge modes to optimize the conversion ratio and minimize energy losses. This parameter adjustment allows the converter to maintain high efficiency across the wide voltage range required for medium- and heavy-duty electric vehicles while preserving high power capability.
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 converter achieves high efficiency and power density by adapting to wide voltage swings, supporting megawatt-scale charging of medium- and heavy-duty vehicles with powertrain voltages up to 1.5 kV, reducing grid instability risks and infrastructure costs.
Implementation Method 1
a transformer isolating the primary circuit from the secondary circuit
Implementation Method 2
a first plurality of capacitors connected in series with each other, the first plurality of capacitors being connected in parallel with the input voltage
Data Source
AI summary
In at least one embodiment, a DC-DC power converter comprises a primary circuit coupled to a DC input voltage, a secondary circuit coupled to a DC output voltage, and a transformer isolating the primary from the secondary circuit. The primary circuit comprises a first and second circuit branch. The first circuit branch comprises a plurality of switches, a diode, and a reconfiguration switch. The second circuit branch comprises a plurality of switches, and a plurality of diodes. The reconfiguration switch is operable to switch the primary circuit between a first mode and a second mode, wherein the primary circuit operates as a full-bridge circuit in the first mode and the primary circuit operates as a half-bridge circuit in the second mode.