Vehicle Power Converter Synchronous Rectification Control
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Solution Overview
Problem
Existing vehicle power converters face challenges in accurately shifting between diode rectification and synchronous rectification, particularly under low-load and high-voltage conditions, leading to inefficient operation and potential failure of synchronous rectification.
Innovation Solution
A vehicle power converter with a load state detecting unit that adjusts the shift conditions based on power generation voltage and load state, using a controller to synchronize switching elements with diodes for synchronous rectification, thereby expanding the operation area for efficient synchronous rectification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If synchronous rectification is performed under low-rotation and low-load state, then rectification efficiency is improved, but induced voltage is lowered causing inaccurate timing calculation and rectification failure
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the synchronous rectification determination threshold based on induced voltage levels. When induced voltage is high, a higher current threshold is used; when induced voltage is low, a lower current threshold is applied. This adaptive threshold adjustment allows synchronous rectification to be reliably determined across varying operating conditions, enabling efficient rectification under low-load states while preventing rectification failure due to inaccurate timing calculation.
2Power
If power generation voltage is increased, then power output capability is improved, but larger power generation current is required to shift from diode rectification to synchronous rectification, narrowing the operation area
Solution Approach 1:
The patent resolves this contradiction by changing the threshold parameter adaptively based on power generation voltage. The synchronous rectification determination threshold is set as a function of both induced voltage and power generation voltage. This allows the system to maintain a broad operation area for synchronous rectification across different voltage levels by adjusting the current threshold accordingly, preventing the operation area from narrowing despite increased power generation voltage.
Solution Approach 2:
The patent applies dynamics by making the rectification style shift dynamic rather than fixed. The control system continuously monitors induced voltage, power generation voltage, and current, and dynamically determines whether to switch between diode rectification and synchronous rectification. This dynamic adaptation enables the system to respond appropriately to changing operating conditions, maintaining optimal rectification efficiency across the full range of power generation voltages and loads.
3Device complexity
If diode rectification is used, then implementation is simple, but rectification efficiency is lower and heat generation is higher
Solution Approach 1:
The patent applies self-service by implementing automatic rectification style selection based on real-time monitoring of operating parameters. The control system automatically determines whether diode rectification or synchronous rectification should be used by evaluating induced voltage, power generation voltage, and current against adaptive thresholds. This eliminates the need for manual intervention or complex control algorithms, allowing the system to self-optimize between simple diode rectification and efficient synchronous rectification based on operating conditions.
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 prevents failures during shifts and enables synchronous rectification across a broader range of conditions, enhancing efficiency and reliability by using load conditions and power generation voltage as shift criteria.
Implementation Method 1
a power generator-motor driven from the external to generate multi-phase AC power
Implementation Method 2
a controller for conducting the switching element corresponding to each diode in synchronization with a conduction state of the diode concerned to perform synchronous rectification
Data Source
AI summary
A vehicle power converter including a plurality of switching elements having diodes connected thereto in parallel and constituting a multi-phase bridge circuit and a controller for conducting the switching element corresponding to each diode in synchronization with a conduction state of the diode concerned to perform synchronous rectification and is connected between a power generator-motor driven from the external to generate multi-phase AC power and DC equipment, further includes a load state detecting unit for detecting a load state of the power generator-motor when the multi-phase AC power occurs, wherein a shift from diode rectification to synchronous rectification or a shift from the synchronous rectification to the diode rectification is carried out in accordance with an output of the load state detecting unit.