Vehicle Power Supply Circuit for Stable Low-Voltage Output
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Solution Overview
Problem
Existing vehicle power supply devices experience unstable low-voltage operation due to changes in high-voltage storage element voltage and current consumption, affecting loads like lighting and wiper mechanisms.
Innovation Solution
A power supply device with a step-down mechanism using a switching means, rectifying means, and smoothing circuit, controlled to maintain a stable low-voltage output by selectively connecting power storage elements and adjusting the ratio of connection time to dead time, ensuring the low-voltage power supply matches the rated operating voltage of the load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a high-voltage power supply with variable voltage is used to supply low-voltage loads, then the power supply can adapt to battery SOC changes, but the low-voltage load operation becomes unstable
Solution Approach 1:
The high-voltage power supply is divided into multiple storage element groups, where each group contains a specific number of power storage elements connected in series. By selectively connecting different groups, the system can provide multiple discrete voltage levels (e.g., 10.4V, 14.4V, 18.4V) to match different load requirements, thereby maintaining load operation stability while adapting to battery SOC changes.
Solution Approach 2:
The switching means dynamically reconfigures the connection of storage element groups based on real-time battery voltage and load current conditions. The control means continuously monitors system state and adjusts the switching configuration to maintain optimal voltage matching between power supply and loads, ensuring stable load operation despite varying battery conditions.
2Power
If the number of power storage elements is increased to maintain voltage, then the power supply capacity increases, but the device complexity and switching losses increase
Solution Approach 1:
Instead of using a single large bank of power storage elements, the system segments them into multiple smaller groups that can be independently connected in series. This segmentation allows the system to achieve high power capacity when needed (by connecting more groups) while keeping the switching complexity manageable through modular group control rather than individual element control.
Solution Approach 2:
The switching means is designed to perform multiple functions: it can connect different numbers of storage element groups in series to generate various voltage levels, balance the operation across different battery modules, and provide over-voltage protection. This multi-functionality reduces the need for separate dedicated circuits for each function, thereby reducing overall device complexity.
3Loss of energy
If fast switching is implemented to reduce switching losses, then the switching loss approaches zero, but the control precision and voltage stability become more difficult to maintain
Solution Approach 1:
The switching means operates in periodic cycles, systematically switching through different storage element group configurations. This periodic operation allows the control means to predict and pre-calculate the optimal switching sequence based on known system parameters, maintaining voltage control precision while achieving fast switching that minimizes energy losses.
Solution Approach 2:
The control means incorporates feedback mechanisms that monitor the actual output voltage and battery state, using this information to adjust the switching timing and duration. This feedback control ensures that even with fast switching, the system maintains precise voltage control and stability by making real-time corrections to the switching parameters.
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 provides a stable low-voltage power supply that maintains consistency across varying storage element voltages, minimizing switching losses and ensuring reliable operation of low-voltage electric loads without changes in illuminance or motor speed.
Implementation Method 1
a high-voltage power supply that provides a high-voltage DC power supply by connecting in series a plurality of power storage elements
Implementation Method 2
said step-down means includes a rectifying means connected to the switching means
Implementation Method 3
a known smoothing circuit that is connected in parallel with the rectifying means, wherein the smoothing circuit comprises an inductor and a capacitor
Data Source
AI summary
A configuration that converts power from high voltage to low voltage by selectively connecting a predetermined storage element group to a low voltage electrical load from a high voltage power supply formed by connecting storage elements in series. In this configuration, the number of storage elements is set such that the voltage of each storage element group is slightly higher than the rated operating voltage of the low voltage electrical load means when the voltage of the storage elements is at its lowest. Along with this, a rectifying means and a smoothing circuit composed of an inductor and a capacitor are provided on the output side of the switching means to control the ratio of ON time and OFF time (dead time) of the switching means. As a result, a stable low-voltage power supply is constructed without being affected by changes in the voltage (SOC) of the storage element.