Pre-Charge Current Circuit With Photocoupler Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-voltage and high-capacity battery packs in electric vehicles often experience a pre-charge phenomenon due to inductive and capacitive elements, leading to excessive current and increased stress on device elements, resulting in potential damage and higher manufacturing costs.
Innovation Solution
A device with a switch, transistors, resistors, and a photocoupler is used to control pre-charge current by generating a base voltage and adjusting the gate voltage of the switch to limit current flow, preventing excessive current and reducing the need for high-cost devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If elements capable of withstanding high current or high voltage are used in device design, then the device can handle pre-charge phenomenon, but the manufacturing cost increases
Solution Approach 1:
The patent introduces a pre-charge control device that activates before the main power connection to gradually charge capacitive elements and limit inrush current. This preliminary action prevents the need for expensive high-current-rated components in the main device by preparing the circuit in advance, thus resolving the contradiction between reliability and manufacturing cost.
2Power
If high-voltage and high-capacity battery packs are used, then the device can drive better, but the pre-charge phenomenon becomes more severe
Solution Approach 1:
The patent introduces a pre-charge control device as an intermediary component between the high-power battery pack and the load. This mediator includes current-limiting circuitry and control logic that manages the pre-charge current flow, allowing high-power battery packs to be used without experiencing severe pre-charge effects, thus resolving the contradiction between power capability and pre-charge current magnitude.
3Device complexity
If the pre-charge current is not controlled, then the device structure remains simple, but the stress on device elements increases
Solution Approach 1:
The patent implements a feedback control mechanism where the pre-charge control device monitors the current flow and adjusts its resistance or switching state accordingly. This feedback system automatically limits stress on device elements during pre-charge without requiring complex structural modifications, resolving the contradiction between device complexity and stress on 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
The solution effectively prevents excessive current and reduces the stress on device elements, minimizing the risk of failure and the need for expensive components in device design and manufacturing.
Implementation Method 1
a photocoupler for receiving, in a state insulated from a first power source, an optical signal from the first power source and supplying power
Data Source
AI summary
A device for controlling a pre-charge current generated when electrically connecting a first terminal and a second terminal, according to one embodiment of the present invention, may comprise: a switch for controlling a magnitude of a current flowing between the first terminal and the second terminal; a first resistor for generating a base voltage of a first transistor in proportion to a magnitude of the pre-charge current flowing between the first terminal and the second terminal; the first transistor for limiting the magnitude of the pre-charge current when a voltage generated by the first resistor is equal to or greater than a predetermined threshold voltage; a photocoupler for receiving, in a state insulated from a first power source, an optical signal from the first power source and supplying power; a capacitor charged by the power supplied by the photocoupler; a second transistor for controlling the magnitude of the pre-charge current on the basis of a charging voltage of the capacitor; and a second resistor for controlling an operating time of the second transistor along with the capacitor.