Bidirectional Current Detection Circuit With Switched Resistors
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Solution Overview
Problem
Existing current detection circuits struggle to accurately detect currents flowing in both directions in a current transformer, leading to increased component count and circuit complexity, particularly in bidirectional and precharging operations.
Innovation Solution
A current detection circuit that switches detection resistors based on the direction of the switching current using a current transformer, incorporating a first and second detection resistor and a reset resistor, with a positive voltage level shift circuit to convert negative voltages to positive, enabling precise current detection in both directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a single current transformer is used for bidirectional operation, then the number of components is reduced, but the ability to detect currents in both directions is lost
Solution Approach 1:
The patent makes a single current transformer serve multiple functions by enabling it to detect currents in both forward and reverse directions. This is achieved by switching the connection configuration of the current transformer based on the operation direction, allowing one component to perform what would traditionally require two separate components.
Solution Approach 2:
The patent introduces dynamic switching of the current transformer's connection configuration based on the operation direction. The current transformer's circuit connections are changed in real-time according to whether the converter is operating in forward or reverse mode, enabling adaptive detection capability without requiring separate static circuits for each direction.
2Measurement precision
If two current transformers are used for forward and reverse operation, then current detection in both directions is achieved, but the circuit scale and component count increase
Solution Approach 1:
The patent merges the functions of two separate current transformers (one for forward operation, one for reverse operation) into a single current transformer. By combining these functions and using switching mechanisms, the patent reduces the total component count while maintaining bidirectional detection capability, directly addressing the issue of increased circuit scale.
3Measurement precision
If a rectifier circuit is used to detect currents in both directions, then detection capability is improved, but the ability to minutely adjust characteristics is reduced
Solution Approach 1:
The patent replaces the static rectifier circuit configuration with a dynamic switching mechanism that can change the circuit's operational state based on the detected current direction. This dynamic approach allows for precise control and adjustment of detection characteristics in both forward and reverse operations, overcoming the limitation of fixed rectifier circuits.
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 allows for precise adjustment of detection characteristics in both directions, reducing nonlinearity and component count, while maintaining accurate current detection even with pulse-shaped direct currents.
Implementation Method 1
a current transformer configured to transform a switching current on a primary side to a secondary side
Implementation Method 2
the value of the switching current is detected by switching the detection resistor and a reset resistor
Data Source
AI summary
A current detection circuit can minutely adjust characteristics when currents flowing in two directions in a current transformer are detected. The current detection circuit is configured to detect a value of a switching current through a detection resistor using a current transformer, and the value of the switching current is detected by switching the detection resistor and a reset resistor on the basis of a flow direction of the switching current flowing on a primary side of the current transformer.