DC-DC Converter Bridge Mode Transition for Soft-Start Charging
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Solution Overview
Problem
Existing battery chargers for automotive vehicles face challenges in achieving high efficiency and power density across varying voltage ranges, particularly with the transition from 400 V to 800 V systems, and require complex and costly soft-start methods for DC-DC converters.
Innovation Solution
A DC-DC converter system with a singular resonant topology that seamlessly transitions between half-bridge and full-bridge modes based on battery voltage and power demand, using software control to manage switching frequency and duty cycles, eliminating the need for additional hardware circuitry for soft-start operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a two-stage layout with AC-DC PFC converter and isolated DC-DC converter is used, then high power density is achieved, but the charger cannot operate at high efficiency for different power requirements
Solution Approach 1:
The patent implements dynamic switching between half-bridge and full-bridge modes based on real-time power demand and battery voltage conditions. The controller adjusts the operating mode to optimize efficiency across different charging scenarios, transitioning from half-bridge at low power to full-bridge at high power, thereby resolving the contradiction between maintaining high power density and achieving high efficiency across varying power requirements
2Reliability
If traditional soft-start methods are used for DC-DC converter, then startup control is achieved, but additional hardware circuitry is required
Solution Approach 1:
The patent replaces traditional hardware-based soft-start circuitry with a software-controlled implementation. The controller uses programmed logic to manage the startup sequence, adjusting switching frequencies and duty cycles through software algorithms rather than additional physical components. This substitution eliminates the need for extra hardware while maintaining reliable startup control
Solution Approach 2:
The soft-start function is implemented as an integrated feature within the existing controller software, allowing the system to self-regulate during startup without external hardware assistance. The controller autonomously manages the ramp-up of power delivery through software-based frequency and duty cycle adjustments
3Adaptability or versatility
If bridge mode transition is implemented, then flexibility across voltage ranges is improved, but switching frequency control complexity increases
Solution Approach 1:
The patent employs dynamic mode transition control where the controller continuously monitors battery voltage and power demand to determine the optimal operating mode. Switching between half-bridge and full-bridge configurations is performed dynamically based on real-time conditions, with the controller adjusting switching frequencies adaptively to maintain optimal performance across the 170V to 850V operating range while managing control complexity through intelligent algorithms
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 system achieves high efficiency and flexibility in charging capabilities across a wide range of voltages and power levels without additional hardware, ensuring smooth startup and reduced stress on components, while being compatible with various AC input power supplies.
Implementation Method 1
a transformer; a bridge driver connected to a primary side of the transformer; and a bridge rectifier connected to a secondary side of the transformer
Data Source
AI summary
A system for a direct current (DC)-DC converter includes a transformer, a bridge driver connected to a primary side of the transformer, and a bridge rectifier connected to a secondary side of the transformer, wherein one or more switches in the bridge driver are operable to configure the bridge driver into each of a half-bridge driver configuration and a full-bridge driver configuration, and to transition between the half-bridge driver configuration and the full-bridge driver configuration while the DC-DC converter is outputting power.