Boost Converter Timing Control to Prevent Voltage Surges
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Solution Overview
Problem
In boost converter apparatuses with multiple converters connected in parallel, there is a risk of voltage surges due to superimposed switching timings, which can exceed the withstand voltage of the load circuit.
Innovation Solution
An electronic control unit is used to manage the switching timings of each boost converter, storing a table of superimposition prohibition regions to avoid timing overlaps, and adjusting target timings to prevent superimposition by shifting them within these regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple boost converters are operated with synchronous switching at the same frequency, then power supply efficiency is improved, but voltage surge occurs due to superimposed switching timings
Solution Approach 1:
The patent applies periodic action by introducing deliberate time offsets between the switching cycles of parallel boost converters. Instead of synchronous switching, each converter operates with a phase-shifted periodic waveform, ensuring that switching events are distributed over time rather than occurring simultaneously. This maintains the benefits of periodic switching while eliminating voltage surge caused by superimposed switching timings.
Solution Approach 2:
The patent introduces asymmetry in the switching timings of parallel boost converters by assigning different phase offsets to each converter. The switching duty cycles and timing profiles are made asymmetric relative to a common reference, preventing simultaneous switching events. This asymmetric timing distribution eliminates the constructive interference that causes voltage surge while maintaining overall system efficiency.
2Speed
If switching frequency is increased to improve response speed, then dynamic performance is improved, but resonance phenomenon occurs in the resonance circuit
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the switching frequency based on the operating conditions and load requirements. The control system monitors the resonance characteristics of the LC circuit and modifies the switching frequency parameter to avoid resonant frequencies. This allows the system to achieve fast response when needed while preventing resonance-induced instability by operating at optimized frequency points.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the output voltage and current of the resonance circuit. The control system uses this feedback information to detect approaching resonant conditions and adjusts the switching frequency accordingly. The feedback loop ensures that the system maintains stable operation even at high switching frequencies by preventing entry into resonant states that would compromise reliability.
3Stability of the object's composition
If phase difference is adjusted to avoid resonance, then system stability is improved, but switching timing control complexity increases
Solution Approach 1:
The patent simplifies the control complexity by implementing a standardized parameter adjustment methodology for phase difference control. Instead of complex adaptive algorithms, the system uses predetermined phase offset parameters that are set based on the number of parallel converters and their switching frequencies. This parameter-based approach maintains system stability by preventing resonance while avoiding the need for complex real-time calculations and control logic.
Data Source
AI summary
An electronic control unit provided in a boost converter apparatus switches a switching element of each of plural boost converters in accordance with each target timing. The electronic control unit stores a table in which a plurality of superimposition prohibition regions are defined. The electronic control unit sets the target timing for each of the plural boost converters in a manner not to be superimposed on any of the plurality of superimposition prohibition regions defined in the table, and updates the table by using a superimposition prohibition region based on the set target timing.