DC/DC Charging Circuit With Soft-Start Bus Pre-Charge
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Solution Overview
Problem
Existing electric vehicle charging devices face high costs and low energy utilization efficiency due to the use of conventional resistors for current-limiting soft start and multiple-level energy conversions, particularly when integrating photovoltaic and energy storage systems.
Innovation Solution
A charging apparatus with a soft-start circuit connected to a DC/DC conversion circuit, pre-charging buses to enable current-limiting soft start, reducing the need for multiple conversion circuits and optimizing energy flow from photovoltaic or energy storage systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional resistors are used for current-limiting soft start in high-power charging devices, then soft start function is achieved, but circuit volume and costs increase due to the need for multiple high-power resistors connected in series or parallel
Solution Approach 1:
The patent changes the working parameter of the soft-start circuit by controlling the duty cycle of the switch tube to adjust the equivalent resistance dynamically. This allows the soft-start circuit to achieve current limiting without requiring multiple high-power resistors, thereby reducing circuit volume while maintaining the soft start function.
2Adaptability or versatility
If multiple conversion circuits (DC/AC, AC/DC, DC/DC) are used to integrate photovoltaic or energy storage systems, then energy conversion capability is achieved, but energy utilization efficiency decreases due to multiple conversion stages
Solution Approach 1:
The patent merges the soft-start circuit with the DC/DC conversion circuit, allowing the DC/DC circuit to perform both soft-start current limiting and power conversion functions. This eliminates the need for separate AC/DC and DC/AC conversion stages when integrating photovoltaic or energy storage systems, reducing the number of conversion stages and improving energy utilization efficiency.
Solution Approach 2:
The DC/DC conversion circuit is designed to serve multiple functions: it acts as both the soft-start circuit for current limiting and the power conversion circuit for energy transformation. This multi-functionality reduces the overall system complexity and minimizes energy losses from multiple conversion stages.
3Adaptability or versatility
If multiple conversion circuits are used in the charging device, then compatibility with different energy sources is improved, but device complexity and costs increase
Solution Approach 1:
The patent combines the soft-start functionality with the DC/DC conversion circuit, eliminating the need for separate conversion circuits. The DC/DC circuit can directly accept input from photovoltaic panels or energy storage batteries and perform both soft-start and power conversion in one stage, thereby reducing device complexity while maintaining compatibility with different energy sources.
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 reduces the volume and cost of the charging apparatus while improving energy utilization efficiency by minimizing impulse currents and requiring fewer conversion stages, enhancing reliability and flexibility.
Implementation Method 1
a soft-start circuit... configured to pre-charge the positive bus and the negative bus
Implementation Method 2
the DC/DC conversion circuit... perform power conversion on a second voltage received from the photovoltaic apparatus or the energy storage apparatus
Data Source
Figure 1A
Figure 1B~2A
Figure 2B~2C
AI summary
This application provides a charging apparatus, a charging pile, and a charging system. The charging apparatus includes a positive bus, a negative bus, a DC/DC conversion circuit, and a soft-start circuit. The soft-start circuit is connected to an input end of the DC/DC conversion circuit through the positive bus and the negative bus, and the input end of the DC/DC conversion circuit is connected to a photovoltaic apparatus or an energy storage apparatus through the positive bus and the negative bus. Therefore, when a first voltage between the positive bus and the negative bus is greater than or equal to a first threshold, the DC/DC conversion circuit may perform power conversion on a second voltage received from the photovoltaic apparatus or the energy storage apparatus, and output the second voltage obtained after power conversion.