Power Converter Current Sensing Using One Sampling Circuit
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Solution Overview
Problem
Inverters have high circuit costs and large printed circuit board (PCB) areas due to the need for multiple current sampling circuits to collect inductive and output currents, which increases complexity and cost.
Innovation Solution
A power converter design that includes a single current sampling circuit to collect the inductive current of an output inductor, allowing the controller to calculate the output current, reducing the need for separate current sampling circuits and minimizing PCB area and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple current sampling circuits are used to collect inductive current and output current separately, then measurement accuracy is improved, but circuit cost and PCB area increase
Solution Approach 1:
The patent merges the functions of collecting inductive current and output current into a single current sampling circuit. The controller differentiates between these two currents through computational processing of the combined signal, thereby reducing the number of physical sampling circuits from two to one while maintaining measurement capability.
Solution Approach 2:
The single current sampling circuit is designed to serve multiple functions: it collects both the inductive current flowing through the output inductor and the output current delivered to the load. This multi-functional approach eliminates the need for separate dedicated sampling circuits for each current type.
2Measurement precision
If multiple current sampling circuits are used to collect inductive current and output current separately, then measurement accuracy is improved, but PCB area increases
Solution Approach 1:
The patent merges the functions of collecting inductive current and output current into a single current sampling circuit. The controller differentiates between these two currents through computational processing of the combined signal, thereby reducing the number of physical sampling circuits from two to one while maintaining measurement capability.
3Device complexity
If a single current sampling circuit is used to collect both inductive current and output current, then circuit cost and PCB area are reduced, but measurement accuracy may deteriorate
Solution Approach 1:
The controller uses feedback mechanisms to process the combined current signal, applying computational algorithms to separate and accurately determine both the inductive current and output current components. This feedback-based signal processing compensates for the loss of physical signal separation.
Solution Approach 2:
The controller acts as an intermediary that receives the combined current signal from the single sampling circuit and performs computational separation to extract the individual inductive and output current values, thereby maintaining measurement accuracy without requiring separate physical sampling paths.
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 reduces circuit costs and PCB area by using a single current sampling circuit to obtain both inductive and output currents, improving accuracy and reducing complexity in the power converter design.
Implementation Method 1
The first current sampling circuit is disposed on a connection line between the midpoint of the second-phase bridge arm and the one end of the output capacitor, and is configured to collect an inductive current of the output inductor
Data Source
AI summary
A power converter includes an output inductor, an output capacitor, a first current sampling circuit, a first-phase bridge arm, a second-phase bridge arm, a third-phase bridge arm, and a controller. A midpoint of the first-phase bridge arm is coupled to a first input end of the power converter. A midpoint of the second-phase bridge arm is coupled to a first end of the output capacitor and a second input end of the power converter. A midpoint of the third-phase bridge arm is coupled to a second end of the output capacitor through the output inductor. The first end is coupled to a second output end of the power converter. The second end is coupled to a first output end of the power converter.