Software Synchronous Rectification for DC-DC Converters
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Solution Overview
Problem
Existing electrified vehicles face inefficiencies in DC-DC converters due to lack of effective synchronous rectification control, leading to suboptimal energy conversion and increased complexity and cost from requiring dedicated hardware.
Innovation Solution
A software-based synchronous rectification control method that determines required output current and switching frequency for DC-DC converters using look-up tables, adjusts turn-on and turn-off delays to maximize efficiency, and compares efficiency to a maximum threshold for continuous optimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If hardware-based synchronous rectification is implemented, then conversion efficiency is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces hardware-based synchronous rectification with a software-based control method. The controller uses pulse-width modulation (PWM) signals with adjustable turn-on and turn-off delays to achieve synchronous rectification effect without dedicated hardware components, thereby reducing device complexity and cost while maintaining conversion efficiency
Solution Approach 2:
The patent changes the control parameters (turn-on delay and turn-off delay) of the PWM signals dynamically based on operating conditions. By adjusting these time delay parameters, the controller optimizes the switching timing of power semiconductor devices to achieve efficient synchronous rectification across different load and voltage conditions
2Ease of operation
If fixed switching frequency is used, then control simplicity is maintained, but conversion efficiency decreases under varying load conditions
Solution Approach 1:
The patent transitions from fixed switching frequency to dynamic switching frequency control. The controller adjusts the switching frequency of the PWM signals in real-time based on the operating conditions (load, input voltage, output voltage) to optimize conversion efficiency across different operating points while maintaining manageable control complexity through established PWM techniques
3Loss of energy
If dynamic delay adjustment is implemented, then conversion efficiency is maximized, but control complexity increases
Solution Approach 1:
The patent implements feedback control where the controller monitors operating conditions (input voltage, output voltage, load current) and dynamically adjusts the turn-on and turn-off delays of PWM signals accordingly. This closed-loop approach maximizes conversion efficiency by optimizing switching timing while keeping control complexity manageable through systematic feedback mechanisms
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 approach eliminates the need for hardware-based synchronous rectification, reduces complexity and cost, and achieves maximum efficiency in DC-DC converters by dynamically adjusting switching delays based on current and voltage measurements.
Implementation Method 1
the DC-DC converter being configured to convert a primary voltage from a primary battery system of the EV to the secondary voltage
Data Source
AI summary
Techniques are presented for synchronous rectification control (SRC) of a DC-DC converter in an electrified vehicle (EV) can include determining a required output current for the DC-DC converter based on a secondary voltage of a secondary battery system of the EV, the DC-DC converter being configured to convert a primary voltage from a primary battery system of the EV to the secondary voltage. The techniques can include determining, at the controller, a switching frequency for the DC-DC converter that causes the DC-DC converter to output the required output current. The techniques can include determining turn-on and turn-off delays of the DC-DC converter based on the required output current and the switching frequency using one or more look-up tables. The techniques can also include controlling the DC-DC converter efficiency based on the turn-on and turn-off delays.