Temperature-Compensated DC-DC Converter for Stable Zero-Voltage Switching
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Solution Overview
Problem
The rise and fall times of switches in DC-DC converters increase due to temperature changes, leading to hard switching and energy loss, particularly in zero voltage transition-partial resonant converters used in aircraft and electric vehicles.
Innovation Solution
A switch temperature compensated DC-DC converter that includes a controller to adjust the on-duty of main and auxiliary switches based on temperature information, using lookup tables to increase the auxiliary switch duty and delay the main switch duty to maintain zero voltage switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the switch temperature increases during operation, then the rise time and fall time of the switch increase, but this leads to hard switching and increased energy loss
Solution Approach 1:
The controller proactively adjusts the on-duty of the auxiliary switch and delays the on-duty of the main switch before temperature-related problems occur. By monitoring switch temperature in real-time and preemptively modifying duty cycles, the system prevents hard switching conditions from developing, thereby avoiding energy loss before it happens.
Solution Approach 2:
The system continuously monitors switch temperature and uses this feedback to dynamically adjust the on-duty of switches. The controller reads temperature information, compares it against reference values, and automatically modifies the switching duty cycles to maintain soft switching conditions, creating a closed-loop control system that adapts to temperature changes.
2Reliability
If the on-duty of the auxiliary switch is increased to compensate for temperature rise, then soft switching is maintained, but the control complexity increases
Solution Approach 1:
The system changes the duty cycle parameter of the auxiliary switch based on temperature conditions. By adjusting this single parameter dynamically according to temperature feedback, the system maintains soft switching reliability without requiring complex structural modifications or multiple control variables.
Solution Approach 2:
The controller acts as an intermediary that translates temperature information into appropriate duty cycle adjustments. It mediates between the temperature sensor and the switch control, using lookup tables to map temperature conditions to optimal duty cycle values, thereby simplifying the control logic while maintaining reliability.
3Ease of operation
If lookup tables are used to store on-duty increase amounts and delay times, then temperature compensation is simplified, but memory requirements increase
Solution Approach 1:
The lookup tables are pre-computed and stored in memory before operation. By calculating and storing the optimal on-duty increase amounts and delay times in advance for various temperature conditions, the system simplifies real-time temperature compensation to simple table lookups, avoiding complex real-time calculations while using minimal memory.
Data Source
AI summary
Proposed is a switch temperature compensated DC-DC converter. The converter may include an input circuit connected to an input terminal and including a main switch. The converter may also include a resonant circuit that is connected to the input circuit and includes an auxiliary switch for zero-voltage switching the main switch. The converter may further include an output circuit connected to the resonant circuit and outputting a voltage to an output terminal. The converter may further include a controller that controls the main switch and the auxiliary switch, in which the controller calculates switch temperature information based on temperature information of at least one measurement target switch among the main switch and the auxiliary switch, and controls on duty of the main switch and the auxiliary switch based on the switch temperature information.