Battery Charger Smoothing Capacitor Input Terminal Integration
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Solution Overview
Problem
Existing battery chargers for electric vehicles suffer from inefficiencies due to the need for multiple switching arms and inductors to correct power factor and smooth charging current, leading to increased switching and iron losses.
Innovation Solution
A battery charger design that reduces the number of switching arms and inductors by using a single smoothing capacitor and a control device to alternately charge and discharge it, allowing selection of either the second or third switching arm based on battery voltage to smooth the charging current, thereby minimizing losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple switching arms and inductors are used to correct power factor and smooth charging current, then the charging current can be smoothed effectively, but switching losses and iron losses increase
Solution Approach 1:
The patent merges the power factor correction function and charging current smoothing function into a single integrated circuit architecture. The smoothing capacitor is connected to the input terminal rather than the output terminal, allowing it to perform both power factor correction and current smoothing simultaneously. This eliminates the need for separate switching arms and inductors dedicated to each function, thereby reducing switching losses and iron losses while maintaining effective current smoothing.
Solution Approach 2:
The smoothing capacitor is designed to serve multiple functions: it acts as both a power factor correction element and a charging current smoothing element. By connecting the capacitor to the input terminal and controlling the switching arm to alternate between the input and output terminals, the system achieves universal functionality with fewer components, reducing overall energy losses.
2Reliability
If multiple switching arms and inductors are used, then power factor correction and current smoothing can be achieved, but device complexity increases
Solution Approach 1:
The patent combines multiple functions into a single integrated circuit structure. The smoothing capacitor is connected to the input terminal and shared between the first and second switching arms, eliminating the need for a dedicated third switching arm and associated inductor. This merging of functions reduces device complexity while maintaining power factor correction and current smoothing capabilities.
Solution Approach 2:
The circuit design employs universal components that perform multiple functions. The smoothing capacitor serves both power factor correction and current smoothing purposes. The first and second switching arms are designed to handle both PFC and smoothing operations by alternating their switching actions, thereby reducing the total number of components needed.
3Reliability
If the smoothing capacitor is connected to the output terminal with a third switching arm, then current smoothing can be achieved, but switching losses and component count increase
Solution Approach 1:
The patent extracts the smoothing function from the output terminal connection and relocates it to the input terminal connection. By connecting the smoothing capacitor to the input terminal and using the existing first and second switching arms to control its charging and discharging, the design eliminates the need for a third switching arm while maintaining effective current smoothing.
Solution Approach 2:
The smoothing capacitor acts as an intermediary element between the input terminal and the rest of the circuit. By positioning the capacitor at the input terminal and using the switching arms to alternate its connection between input and output terminals, the system achieves current smoothing without requiring a dedicated third switching arm, thereby reducing component complexity.
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 design reduces switching and iron losses by utilizing fewer components, allowing for more efficient energy transfer and extending battery life by smoothing the charging current effectively.
Implementation Method 1
a smoothing capacitor having a first end connected to the second output terminal, a connecting device for connecting a second end of the smoothing capacitor to the second input terminal
Implementation Method 2
two inductors having first ends connected respectively to the first input terminal and the second input terminal
Data Source
Figure 1~3
Figure 4
AI summary
The battery charger comprises: two output terminals (BS1, BS2) between which a battery (102) is intended to be connected; two input terminals (BE1, BE2) intended to be connected to an electrical network (110); two inductors (LA, LC) connected respectively to the first input terminal (BE1) and the second input terminal (BE2); two switching arms (BA, BC) intended to selectively connect the inductors (LA, LC) to the first output terminal (BS1) and the second output terminal (BS2), respectively; a control device (120) intended to control the switching arms (BA, BC) so as to draw from the electrical network (110) a network current (iR) in phase with the network voltage (uR). The battery charger further comprises: a smoothing capacitor (C) connected to the second output terminal (BS2); and a connection device (112) for connecting the smoothing capacitor (C) to the second input terminal (BE2).The control device (120) is further intended to control at least the second switching arm (BC) so as to alternately charge and discharge the smoothing capacitor (C) to smooth the charging current (iB).