DC-DC Converter Start-Up Control for Balanced Battery Current
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Solution Overview
Problem
Conventional DC-DC converters experience unnecessary current and power output during start-up, leading to biased current flow and potential degradation of connected batteries.
Innovation Solution
A DC-DC converter design featuring a series assembly of switching elements, inductance element, and a controller that determines complementary ON-periods based on high-side and low-side voltages, suppressing steady current flow and balancing power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If switching elements are started to turn on and off based on voltage ratios in conventional DC-DC converters, then power conversion function is achieved, but unnecessary current and power output occur during start-up leading to battery degradation
Solution Approach 1:
The controller performs preliminary determination of ON-period lengths based on voltage ratios before actual switching operation begins. During start-up, the controller first calculates appropriate ON-periods for each switching element based on the detected voltage ratio, then applies these pre-calculated timing parameters to prevent unnecessary current flow from the outset
Solution Approach 2:
The controller continuously detects the voltage ratio between input and output sides, uses this feedback information to dynamically adjust and determine the ON-period lengths of switching elements, ensuring optimal switching timing that prevents unnecessary current flow while maintaining efficient power conversion under varying load conditions
2Device complexity
If conventional switching control is used without considering start-up conditions, then device complexity is reduced, but biased current flow occurs causing harmful effects on connected batteries
Solution Approach 1:
The controller changes the timing parameters (ON-period lengths) of switching elements based on detected voltage ratios. By dynamically adjusting these parameters rather than using fixed timing, the system prevents biased current flow during start-up and under varying load conditions without requiring complex additional circuitry
Solution Approach 2:
The switching control transitions from static fixed timing to dynamic adaptive timing. The controller continuously adjusts the ON-period lengths of switching elements based on real-time voltage ratio detection, enabling the system to adapt to changing operating conditions and prevent harmful current patterns
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 suppresses unnecessary current and power output during start-up, maintaining a balanced state with minimal current flow, thereby preventing battery degradation.
Implementation Method 1
inductance element having one end connected to the node
Data Source
AI summary
In a DC-DC converter, a controller is configured to provide control cycles subsequently. Each of the control cycles includes a first ON-period and a second ON-period subsequent to the first ON-period. One switching element is turned on, and another switching element is turned off the first ON-period. The one switching element is turned off, and the another switching element is turned on for the second ON-period. A controller is configured to determine lengths of the first and second ON-periods based on high-side and low-side voltages. The controller is configured to turn on the one switching element in an initial ON-duration in the first ON-period of a control cycle among the control cycles which is firstly provided. The initial ON-duration has a length shorter than the determined length of the first ON-period. The controller turns off the one and another switching elements in a duration in the first ON-period in the first control cycle other than the initial ON-duration. The controller is configured to turn on the one switching element and turn off the another switching element for the determined length of the first ON-period of each of one or more control cycles among the control cycles other than the first control cycle. The controller is configured to turn off the one switching element and turn on the another switching element for the determined length of the second ON-period of each of the control cycles.