Bidirectional DC-DC Converter Modulation Switching for Real-Time Efficiency
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Solution Overview
Problem
Existing power conversion methods for DC-DC converters, particularly bidirectional isolated converters, face inefficiencies due to the need for offline calculations and lack of real-time adaptation of modulation algorithms, leading to reduced performance at varying power levels and load conditions.
Innovation Solution
A power conversion method that calculates average power in real-time using both SPWM and DPWM algorithms, selecting the optimal algorithm at every control cycle to improve efficiency and eliminate the need for offline calculations, thereby enhancing reliability and efficiency across different power levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If PSM algorithm is used, then ease of operation is improved, but efficiency deteriorates when light load and input-output ratio increase
Solution Approach 1:
The system dynamically selects between PSM, SPWM, and DPWM algorithms based on real-time operating conditions (load level, input-output voltage ratio). The control unit adjusts the modulation algorithm dynamically rather than using a fixed method, allowing optimal efficiency across varying operating conditions while maintaining ease of operation through automated selection.
2Loss of energy
If DPWM algorithm is used, then efficiency at low power levels is improved, but device complexity increases
Solution Approach 1:
The control algorithm is segmented into multiple modes (PSM, SPWM, DPWM) that are selected based on operating conditions. Instead of implementing a single complex DPWM system, the invention divides the control strategy into manageable segments, using DPWM only when beneficial (low power levels) while simpler algorithms handle other conditions, reducing overall system complexity.
Solution Approach 2:
The system dynamically switches between different modulation algorithms based on real-time power level detection. DPWM is activated only when operating conditions indicate it will improve efficiency, rather than being permanently implemented, thus achieving low-power efficiency without permanently increasing device complexity.
3Loss of energy
If hybrid method using DPWM and SPWM is used, then conversion efficiency is improved, but loss of time increases due to repetitive offline calculations
Solution Approach 1:
The invention replaces offline calculations with real-time model-based power calculations. Instead of pre-calculating optimal parameters offline and storing them for lookup, the system performs rapid real-time calculations using established models, eliminating the time loss associated with repetitive offline computations while maintaining high conversion efficiency.
Solution Approach 2:
The system prepares calculation models in advance that can be rapidly applied in real-time operation. By having the mathematical models ready and structured for quick computation, the system avoids time-consuming offline calculations during operation, achieving both high efficiency and fast response.
4Device complexity
If pre-obtained values are used offline, then device complexity is reduced, but reliability deteriorates when input and output voltages change
Solution Approach 1:
The system transitions from static pre-obtained values to dynamic real-time calculations. The control unit continuously computes optimal parameters based on current input and output voltage conditions, ensuring reliability when operating conditions change while keeping device complexity manageable through efficient real-time computation algorithms.
Solution Approach 2:
The system incorporates feedback from real-time voltage and power measurements to continuously adjust modulation algorithm parameters. This feedback mechanism ensures that the system adapts to changing input and output voltages, maintaining high reliability without requiring complex pre-programmed lookup tables for every possible condition.
Data Source
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AI summary
A method for determining a scheme for converting power in every power conversion control period and converting power according to the determined scheme may comprise the steps of: calculating average power in a transformer inductor at the time of power conversion according to an SPWM scheme in a control period; calculating average power in the transformer inductor at the time of power conversion according to a DPWM scheme in a control period; and converting power according to a scheme by means of which the calculated average power of the transformer inductor is greater. Here, in the step of calculating the average power in the transformer inductor at the time of power conversion according to the DPWM scheme, it is possible to select a DPWM scheme with the maximum duty in a step-up or step-down condition given in the control period.