Multi-output DC-DC Converter Nonlinear Inductance Cross-regulation
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Solution Overview
Problem
Conventional multi-output DC-DC converters face challenges in maintaining optimal cross-regulation performance due to fixed leakage inductance in output inductors, leading to deteriorated performance when load conditions change, causing output currents to enter discontinuous conduction mode.
Innovation Solution
Incorporating nonlinear inductive elements with variable inductance on output channels, where inductance decreases with increasing current, allowing leakage inductance to adjust according to load changes, preventing discontinuous conduction mode and enhancing cross-regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fixed leakage inductance output inductors are used, then the converter structure is simple, but the cross-regulation performance deteriorates when load conditions change
Solution Approach 1:
The patent applies the dynamics principle by replacing fixed leakage inductance with variable leakage inductance that automatically adjusts according to load conditions. The variable inductive element changes its inductance value dynamically - increasing inductance when load decreases to prevent discontinuous conduction mode, and decreasing inductance when load increases. This dynamic adaptation resolves the contradiction by maintaining optimal cross-regulation performance across varying loads without requiring complex external control circuits.
Solution Approach 2:
The patent implements parameter changes by modifying the leakage inductance parameter of the output inductor from a fixed value to a variable value that changes with load current. The variable inductive element is designed to exhibit different inductance characteristics under different operating conditions, thereby optimizing cross-regulation performance. This parameter change approach allows the system to adapt to varying load conditions while maintaining a relatively simple overall structure.
2Reliability
If fixed leakage inductance is used in output inductors, then the device structure remains simple, but output currents enter discontinuous conduction mode under light load conditions
Solution Approach 1:
The dynamics principle is applied by using a variable inductive element whose inductance automatically increases under light load conditions. This dynamic adjustment prevents the output current from entering discontinuous conduction mode by maintaining sufficient inductance to sustain continuous current flow. The variable inductance characteristic ensures stable continuous conduction mode operation across the full load range without adding complex control mechanisms.
Solution Approach 2:
The variable inductive element performs self-service by automatically adjusting its inductance value based on the load current without requiring external sensing or control circuits. The element inherently exhibits higher inductance at lower currents, which self-regulates to prevent discontinuous conduction mode. This self-adjusting characteristic maintains reliable continuous conduction while keeping the device structure simple.
3Reliability
If the leakage inductance is optimized for heavy load conditions, then heavy load performance is good, but cross-regulation performance deteriorates under light load conditions
Solution Approach 1:
The patent applies parameter changes by designing the variable inductive element to exhibit different inductance values optimized for different load conditions. The element automatically transitions between inductance states - providing lower inductance for heavy loads and higher inductance for light loads. This parameter adaptation ensures optimal cross-regulation performance across the entire load range while maintaining a relatively simple implementation without requiring multiple discrete inductors or complex switching mechanisms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly improves cross-regulation performance by dynamically adjusting leakage inductance in response to load changes, maintaining stable output voltages across multiple outputs.
Implementation Method 1
At least one secondary circuit is provided with a nonlinear inductive element being placed on an output channel thereof, in which the inductance of the nonlinear inductive element is variable according to the change of the current flowing through the nonlinear inductive element
Implementation Method 2
a transformer having a primary winding and a plurality of secondary windings, in which the primary winding is connected to the switch for receiving an input DC voltage and each secondary winding is configured to induce an AC voltage
Data Source
AI summary
A multi-output DC-DC converter that can optimize its cross-regulation performance is proposed, in which a nonlinear inductive element functioning as a leakage inductance of an output coupled inductor is placed on the output channel of at least one secondary circuit coupled to a secondary winding of a transformer. The inductance of the nonlinear inductive element is varied in inverse proportion with the variation of the current flowing through the nonlinear inductive element. When the load on an output end of the DC-DC converter is changed, the output channel having a higher load current is configured to produce a lower leakage inductance and the output channel having a lower load current is configured to produce a higher leakage inductance, and thereby balance the output currents flowing through the output channels of the DC-DC converter.