DC Power Supply Device with Segmented Voltage Conversion
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Solution Overview
Problem
Existing DC power supply devices experience significant power loss when converting AC voltage to DC voltage for electric tools, particularly when outputting low voltage, due to high current flow in cables.
Innovation Solution
A DC power supply device with a first conversion unit that converts AC voltage to a higher DC voltage and outputs it through a cable to a second conversion unit, which then reduces the voltage to a suitable level for the electric tool, incorporating power factor correction, boosting, and smoothing circuits, along with a cutoff circuit and cooling fans for efficiency and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a low voltage is output from the converter unit, then the electric tool can be supplied with required large power, but the power loss in the cable becomes particularly large
Solution Approach 1:
The power conversion function is divided into two separate conversion units: a first conversion unit that converts AC voltage to high voltage DC, and a second conversion unit that converts high voltage DC to low voltage DC for the electric tool. This segmentation allows the cable to transmit high voltage low current (reducing power loss) while still delivering the required power to the tool.
Solution Approach 2:
The first conversion unit acts as an intermediary that converts AC power to high voltage DC power suitable for cable transmission. This intermediary conversion enables the cable to efficiently transmit power over distance with minimal loss, and the second conversion unit then converts it to the required low voltage for the electric tool.
2Weight of moving object
If the adapter is made small-size and lightweight to match battery pack shape, then it can be conveniently connected to the electric tool, but the converter unit must be provided separately with additional circuit elements
Solution Approach 1:
The system is segmented into a compact adapter portion that interfaces with the electric tool and a separate first conversion unit that performs the AC to high voltage DC conversion. This segmentation allows the adapter to remain small and lightweight while the bulk of the conversion circuitry is located in the separately provided first conversion unit.
Solution Approach 2:
The heavy and complex circuit elements (rectifier circuit, smoothing circuit, transformer) are extracted from the adapter and placed in a separately provided first conversion unit. This extraction allows the adapter to be minimized in size and weight while still providing the complete power conversion functionality through the combined system.
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 reduces power loss in cables, enhances safety by cutting off voltage in case of cable breakage, allows for a smaller and lighter second conversion unit connected to the electric tool, and mimics the output characteristics of a battery pack for improved usability and protection against abnormalities.
Implementation Method 1
a rectifier circuit, a smoothing circuit and a transformer are provided in a converter unit
Implementation Method 2
a rectifier circuit, a smoothing circuit and a transformer are provided in a converter unit
Implementation Method 3
The first conversion unit may include a first cooling fan generating cooling air inside the first conversion unit. The second conversion unit may include a second cooling fan generating cooling air inside the second conversion unit.
Data Source
AI summary
A DC power supply device includes a first conversion unit connected to an AC power supply, a second conversion unit connected to an electric tool, and a cable connecting the first conversion unit and the second conversion unit to each other. The first conversion unit includes a power factor correction circuit, converts an AC voltage having a first voltage value, input from the AC power supply, into a DC voltage having a second voltage value higher than the first voltage value, and outputs the DC voltage having the second voltage value to the cable. The second conversion unit converts the output voltage of the first conversion unit, input via the cable, into a DC voltage having a third voltage value lower than the second voltage value, and outputs the DC voltage having the third voltage value to the electric tool.