Buck-Boost Converter Switching at Voltage Minima to Cut Losses
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Solution Overview
Problem
Existing actuation methods for buck-boost converters, particularly at high input and output voltages, result in high switching losses and interference emissions due to fixed-frequency actuation, which is suboptimal for switching element timing and leads to inefficiencies.
Innovation Solution
A method for actuating a buck-boost converter using pulse-width-modulated and frequency-modulated control signals with a common, variable switching frequency. The switching elements are actuated based on a voltage curve monitoring, switching on simultaneously at a voltage minimum or after a predetermined period, ensuring switching frequencies remain within defined limits to minimize losses and emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed-frequency actuation is used for switching elements, then the control is simplified, but switching losses and interference emissions increase at high voltages
Solution Approach 1:
The patent applies dynamics by transitioning from fixed-frequency actuation to variable switching frequency. The switching frequency is dynamically adjusted based on the instantaneous voltage conditions, allowing the system to optimize performance at different operating points. This is achieved through voltage curve monitoring that triggers switching events at optimal moments rather than at fixed intervals, reducing switching losses while maintaining manageable control complexity through automated detection.
Solution Approach 2:
The patent changes the frequency parameter of the switching signals from constant to variable. By monitoring the voltage curve and adjusting the switching frequency based on detected voltage minima or predetermined time intervals, the system adapts its operating parameters to minimize energy losses. This parameter change allows the converter to operate efficiently across different voltage conditions without requiring complex manual tuning.
2Device complexity
If fixed-frequency actuation is used for switching elements, then the circuit design is simplified, but interference emissions increase at high voltages
Solution Approach 1:
The patent uses dynamic switching frequency adjustment to reduce interference emissions. By varying the switching frequency based on voltage conditions rather than operating at a fixed frequency, the system avoids consistent electromagnetic interference patterns. The automated voltage curve monitoring and adaptive triggering mechanism maintains circuit design simplicity while effectively reducing harmful emissions through intelligent timing control.
3Loss of energy
If switching elements are actuated at optimal voltage minima, then switching losses are reduced, but the control complexity increases
Solution Approach 1:
The patent implements self-service through automated voltage curve monitoring and automatic detection of voltage minima. The system monitors its own operating conditions and autonomously determines the optimal switching moments without requiring external intervention or complex control algorithms. This self-monitoring and self-adjusting mechanism reduces switching losses while keeping control complexity manageable through straightforward voltage threshold detection and automatic triggering.
Solution Approach 2:
The patent employs feedback by continuously monitoring the voltage curve and using this information to trigger switching events. The system measures the actual voltage conditions, compares them against predetermined criteria (voltage minima or time intervals), and adjusts switching timing accordingly. This closed-loop feedback approach optimizes switching performance while maintaining simple control logic through straightforward comparison and triggering mechanisms.
4Productivity
If variable switching frequency is used, then efficiency is improved, but the switching frequency control becomes more complex
Solution Approach 1:
The patent changes the switching frequency parameter from fixed to variable based on operating conditions. By monitoring voltage curves and adjusting frequency according to detected minima or predetermined time intervals, the system improves converter efficiency across different operating points. The control complexity is managed through straightforward parameter adjustment based on easily measurable voltage conditions rather than complex multi-parameter optimization.
Data Source
AI summary
A method for actuating a DC-to-DC converter, in particular a clocked buck-boost converter that includes at least two switch elements and an inductor or throttle and via which an input voltage is converted into a regulated output voltage, wherein the switch elements are actuated with a variable switch frequency using pulse- and frequency-modulated control signals, where the pulse- and frequency-modulated control signals are derived from a manipulated variable from a regulator, a voltage curve on the switch elements is continuously ascertained or monitored to determine the activation time of the switch elements and to start a new switch cycle, the switch elements are activated if a specified minimum period duration has been exceeded upon detecting a voltage minimum of the ascertained voltage curve on the switch elements.