Switching Energy Converter Intermittent Stabilization
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Solution Overview
Problem
Switching energy converters experience sub-harmonic instabilities due to the use of stabilization ramps, which lead to inaccuracies in current control, especially at high duty cycles and variable input voltages, resulting in over-dimensioning of inductive components and accuracy issues in applications like airplane electric networks.
Innovation Solution
A control device that applies an intermittent stabilization signal, subtracted from or added to the set value signal, at a predetermined instant before the reference instant, to reduce the impact of continuous stabilization ramps on current control accuracy, specifically for duty cycles greater than ½ and dynamically adjusted based on input and output voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a continuous stabilization ramp is applied to eliminate sub-harmonic instabilities, then the stability of the converter is improved, but the accuracy of current control deteriorates due to the static bias introduced by the ramp
Solution Approach 1:
The patent applies the stabilization ramp intermittently rather than continuously. The ramp is activated only during specific switching cycles when sub-harmonic instability is detected, and deactivated during other cycles. This periodic application maintains system stability while eliminating the continuous static bias that degrades current control accuracy.
Solution Approach 2:
The patent dynamically adjusts the parameters of the stabilization ramp based on operating conditions. The ramp slope and application timing are modified according to the duty cycle and input voltage levels, allowing optimal stability performance across different operating points while minimizing the impact on current control accuracy.
2Productivity
If the duty cycle is greater than ½, then the converter operates in a specific mode, but sub-harmonic instabilities occur requiring stabilization ramps that reduce current control accuracy
Solution Approach 1:
The patent implements dynamic control of the stabilization ramp parameters based on the duty cycle. When the duty cycle exceeds ½, the ramp parameters are automatically adjusted to provide appropriate stabilization while minimizing accuracy degradation. This dynamic adaptation allows the system to maintain high productivity in different operating modes without sacrificing current control precision.
3Reliability
If a stabilization ramp is applied to stabilize the converter, then reliability is improved, but inductive components must be over-dimensioned to compensate for the bias introduced by the ramp
Solution Approach 1:
By applying the stabilization ramp periodically rather than continuously, the patent reduces the cumulative bias effect on the inductive components. The intermittent application provides sufficient reliability improvement to eliminate sub-harmonic instabilities while minimizing the need for over-dimensioning the inductors and other magnetic components.
Data Source
AI summary
This converter includes a controllable switch (M) and a control device (311) for generating a signal for controlling the opening and closing instants of the switching switch, the control device being of the control device type in a current mode requiring the application of a current stabilization signal. The control device includes a component (20) delivering a stabilization signal (RC) intermittently, by applying the stabilization signal (RC) at a predetermined instant which precedes a reference instant; and a comparator (28) for generating a control signal (CM) of the controllable switch (M) from the comparison of a set value signal (IL) and of a measurement signal corresponding to the current (IL) flowing in an impedance (L) of the converter, the intermittent stabilization signal (RC) being subtracted from the set value signal (IL) or added to the measurement signal before applying the comparator.