In-Vehicle Power Supply Device Partial Switching Precharge
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Solution Overview
Problem
In-vehicle power supply systems face challenges in reducing inrush currents and ensuring control unit operation during precharge, especially when the power supply voltage drops due to increased parallelization of switching elements in DC-DC converters, leading to voltage drops in resistive and diode components.
Innovation Solution
An in-vehicle power supply device with a configuration that includes a first and second conductive path, a switch unit, and a voltage conversion unit with a reverse-flow prevention switching element, allowing for voltage boosting or lowering between paths, and a control unit that alternately switches semiconductor switching elements to perform voltage conversion operations, minimizing power consumption and preventing voltage drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple switching elements are arranged in parallel to increase DC-DC converter capacity, then power conversion capability is improved, but voltage drop in resistive components increases causing power supply voltage to drop
Solution Approach 1:
The reverse-flow prevention switching element is divided into multiple semiconductor switching elements connected in parallel. During precharge operation, only a subset of these elements is activated, segmenting the current path to minimize voltage drop across resistive components while maintaining sufficient power conversion capability.
Solution Approach 2:
Instead of activating all parallel switching elements during precharge, the control unit activates only some of them (partial action). This reduces the current through resistive components and minimizes voltage drop, while still providing adequate precharge current to suppress inrush current when the main switch unit turns on.
2Reliability
If precharge operation is performed using DC-DC converter, then inrush current is suppressed, but power consumption increases causing voltage drop that may prevent control unit operation
Solution Approach 1:
The control unit performs precharge operation only when necessary (when switch unit transitions from OFF to ON state), and activates only some of the parallel switching elements in the reverse-flow prevention switching element. This partial operation reduces power consumption while still achieving sufficient precharge to suppress inrush current.
Solution Approach 2:
The control unit performs precharge operation in advance before the main switch unit turns on. By charging the capacitive component beforehand using the second voltage conversion unit with reduced power consumption, the system ensures inrush current suppression while minimizing impact on the power supply voltage for control unit operation.
3Adaptability or versatility
If power supply voltage drops due to increased parallelization, then more switching elements can be driven, but driver operation may fail due to insufficient voltage
Solution Approach 1:
The system uses partial activation of parallel switching elements during precharge operation, which reduces voltage drop across resistive components and maintains power supply voltage at levels sufficient for reliable driver and control unit operation, while still providing adequate drive capability for the activated elements.
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 configuration effectively suppresses inrush currents during precharge and ensures the control unit can perform precharge operations even if the power supply voltage drops, by minimizing power consumption and maintaining necessary drive voltages for the control unit.
Implementation Method 1
a first voltage conversion unit that includes a first inductor and a drive switching element that is turned ON/OFF in accordance with a first control signal
Implementation Method 2
a second voltage conversion unit is configured by including the reverse-flow prevention switching element, the second inductor, and the semiconductor element part
Data Source
AI summary
The present disclosure aims to reduce the changes that a control unit receiving power supplied from a power supply cannot perform control of a precharge operation even if the power supply voltage drops. In a power supply device, a reverse-flow prevention switching element is configured such that a plurality of semiconductor switching elements are connected in parallel with each other. The control unit, in accordance with a predetermined precharge condition being fulfilled, causes the second voltage conversion unit to perform the second voltage conversion operation by supplying a second control signal for switching to an ON signal and an OFF signal alternately to only some of the plurality of semiconductor switching elements constituting the reverse-flow prevention switching element.