Parallel Boost Converter Phase Control for Battery Warm-Up
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Solution Overview
Problem
Existing systems for battery warm-up in battery electric vehicles do not effectively increase the heat generation by ripple current in boost converters.
Innovation Solution
A control device and method that adjusts the phases of multiple boost converters to be in-phase when current exceeds a threshold and stops some converters when current falls below the threshold, increasing ripple current and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the phases of multiple boost converters are adjusted to be in the same phase, then the amount of heat generated by the secondary battery is increased, but the current value flowing through each boost converter decreases
Solution Approach 1:
The control unit dynamically adjusts the operating phases of multiple boost converters based on real-time current conditions. When current exceeds a threshold, converters operate in the same phase to maximize heat generation for battery warm-up. When current falls below the threshold, the control unit dynamically reconfigures converters to opposite phases to maintain current flow and prevent deterioration, thus adaptively resolving the contradiction between heat generation and current maintenance
Solution Approach 2:
The system changes the phase parameter of boost converter operations based on current threshold conditions. By switching between 'same phase' mode (for heat generation) and 'opposite phase' mode (for current maintenance), the system dynamically adjusts operational parameters to resolve the contradiction between maximizing heat output and maintaining sufficient current flow through individual converters
2Power
If all boost converters operate simultaneously, then the current value flowing through each converter is maintained, but the amount of heat generated by the secondary battery is reduced
Solution Approach 1:
The control unit implements periodic assessment of current values against thresholds and periodically switches between operational modes. During periods when current is high, converters operate in same-phase mode to generate heat. When current drops below threshold, the system periodically transitions to opposite-phase mode to restore current flow, creating a rhythmic switching pattern that balances heat generation and current maintenance over time
3Temperature
If the ripple current is increased for battery warm-up, then the heat generation is increased, but the inductance of the reactor decreases
Solution Approach 1:
The system exploits the inherent characteristic that reactor inductance decreases with increased current flow. By operating multiple boost converters in same-phase mode, the increased total current causes inductance to decrease, which in turn increases ripple current and heat generation. The system converts the potentially harmful effect of decreased inductance into a beneficial increase in heat generation for battery warm-up
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
Enhances battery warm-up by increasing ripple current, maintaining current flow, and preventing device deterioration at low temperatures.
Implementation Method 1
the amount of heat generated by the secondary battery based on the magnitude (total value) of the ripple current can be increased
Data Source
AI summary
The boost converter control device includes a plurality of boost converters connected in parallel to each other with respect to the secondary batteries, and an ECU (control unit) that controls each of the plurality of boost converters. When warm-up of the secondary battery is required, ECU performs a first control for adjusting the phases of the plurality of boost converters to be in phase with each other in response to the current value flowing through the secondary battery becoming larger than a predetermined threshold, and performs a second control for stopping the operation of a part of the plurality of boost converters in response to the current value flowing through the secondary battery becoming equal to or smaller than the predetermined threshold.