Variable Voltage Converter Switching Frequency Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Variable voltage converters in electrified vehicles face inefficiencies due to switching losses, particularly when operating at high currents and duty cycles, which affect fuel economy and noise vibration harshness (NVH) issues.
Innovation Solution
A controller programmed to adjust the switching frequency of the variable voltage converter based on the magnitude of the difference between the operating duty cycle and a predetermined duty cycle value, as well as the current input, to minimize switching losses and ripple current magnitude, while maintaining the frequency within predetermined limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the switching frequency is increased to reduce ripple current magnitude, then the ripple current magnitude decreases, but the switching loss increases
Solution Approach 1:
The patent implements dynamic switching frequency adjustment based on real-time operating conditions. The controller monitors the duty cycle and current input, then adapts the switching frequency accordingly - using higher frequencies when ripple current needs reduction and lower frequencies when switching loss needs reduction, rather than operating at a fixed frequency
Solution Approach 2:
The patent changes the switching frequency parameter dynamically based on operating conditions. By adjusting this key parameter according to duty cycle and current input levels, the system optimizes the trade-off between ripple current magnitude and switching loss for different operating scenarios
2Loss of energy
If the switching frequency is decreased to reduce switching loss, then the switching loss decreases, but the ripple current magnitude increases
Solution Approach 1:
The system dynamically adjusts switching frequency based on real-time monitoring of duty cycle and current input. When operating conditions indicate low ripple current risk, the frequency is reduced to minimize switching losses, and when ripple current becomes problematic, the frequency is increased to suppress it
Solution Approach 2:
The switching frequency parameter is changed dynamically according to operating conditions. The controller modifies this parameter based on the relationship between duty cycle, current input, and their differences from reference values, optimizing the balance between switching loss and ripple current
3Device complexity
If a fixed switching frequency is used, then the control system is simple, but the system cannot adapt to varying operating conditions to optimize efficiency
Solution Approach 1:
The patent implements a feedback control mechanism where the controller continuously monitors duty cycle and current input, compares them to reference values, and adjusts the switching frequency accordingly. This closed-loop feedback enables the system to adapt to varying operating conditions while maintaining manageable control complexity
Solution Approach 2:
The control system automatically adjusts the switching frequency based on its own monitoring of operating conditions without external intervention. The controller uses the measured duty cycle and current input to self-regulate the switching frequency, making the system self-adaptive to different operating scenarios
Data Source
AI summary
A voltage converter includes a switch having a switching loss that decreases as a switching frequency of the switch decreases. The voltage converter further includes a controller programmed to vary the switching frequency based on a duty cycle of the switch and a current input to the switch to reduce switching losses or reduce a ripple current magnitude.