Self-Oscillating Resonant Power Converter Frequency Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing resonant power converters face challenges in achieving flexible, rapid, and accurate control of output voltage due to limitations in adjustable inductances and capacitances, which restrict the regulation range and speed of switching frequency, especially at high frequencies.

Innovation Solution

The use of a self-oscillating feedback loop with a substantially fixed inductor and an adjustable bias voltage allows for control of the oscillation frequency without adjusting the inductance, enabling wide and accurate control of the switching frequency, reducing power losses in parasitic capacitances, and eliminating the need for variable reactive components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If adjustable inductances and capacitances are used to control switching frequency, then the regulation range can be extended, but the regulation speed is limited and power losses increase

Engineering Contradiction:
Improveregulation rangeVSAvoidregulation speed
Core Design Contradiction:
Adaptability or versatilityVSSpeed

Solution Approach 1:

The patent replaces mechanical adjustment of inductance/capacitance values with an electrical control method. A fixed inductor combined with an adjustable bias voltage source controls the switching frequency through voltage adjustment rather than physical component changes, enabling both wide regulation range and fast response speed without the inertia associated with mechanical or reactive component adjustment.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the control parameter from inductance/capacitance values to bias voltage level. By adjusting the bias voltage applied to the fixed inductor, the switching frequency can be rapidly varied over a wide range without changing the physical characteristics of reactive components, thus achieving both adaptability and speed.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If adjustable inductances and capacitances are used to control switching frequency, then the regulation range can be extended, but power losses in parasitic capacitances increase

Engineering Contradiction:
Improveregulation rangeVSAvoidpower losses
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent eliminates the need for adjustable reactive components that inherently cause power losses in their parasitic elements. By using a fixed inductor with adjustable bias voltage, the control mechanism avoids the resistive losses associated with variable inductors and capacitors, achieving wide regulation range with reduced power consumption.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts the adjustable element (bias voltage) from the reactive component (inductor/capacitor) itself. Instead of making the inductor or capacitor adjustable, the invention applies an adjustable voltage to a fixed inductor, thereby removing the source of parasitic capacitance losses while maintaining frequency control capability.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If variable reactive components are used, then the switching frequency can be controlled, but the device complexity and component count increase

Engineering Contradiction:
Improvefrequency controlVSAvoidcomponent count
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts the variability function from the reactive component and places it in the voltage source. Instead of using a variable inductor or capacitor, the invention uses a fixed inductor controlled by an adjustable bias voltage, thereby simplifying the circuit by removing variable reactive components while maintaining frequency control capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The fixed inductor serves multiple functions: it provides the necessary reactance for resonance and simultaneously acts as the frequency-determining element when combined with the adjustable bias voltage. This multi-functionality reduces the need for separate variable reactive components, simplifying the overall circuit design.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 provides flexible and rapid control of the converter output voltage, enhancing the regulation range and speed, and reducing power losses, while integrating the inductor into the circuitry for size and cost advantages.

Implementation Method 1

The self-oscillating feedback loop sets a switching frequency of the power converter and comprises a first intrinsic switch capacitance coupled between a switch output and a control input of the switching network and a first inductor

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

The first inductor is coupled in-between a first bias voltage source and the control input of the switching network and has a substantially fixed inductance

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2915245B1Self-oscillating resonant power converter
Publication Date: 2020.03.04 DANMARKS TEKNISKE UNIV
  • EP2915245B1 patent drawingFigure 1A~1B
  • EP2915245B1 patent drawingFigure 2A~2B
  • EP2915245B1 patent drawingFigure 2C

AI summary

The present invention relates to resonant power converters and inverters comprising a self-oscillating feedback loop coupled from a switch output to a control input of a switching network comprising one or more semiconductor switches (S1, S2). The self-oscillating feedback loop sets a switching frequency of the power converter (100) and comprises a first intrinsic switch capacitance (CGD) coupled between a switch output and a control input of the switching network and a first inductor (LG). The first inductor (LG) is coupled in-between a first bias voltage source and the control input of the switching network and has a substantially fixed inductance. The first bias voltage source is configured to generate an adjustable bias voltage (VBias) applied to the first inductor ( LG). The output voltage (V0UT) of the power converter (100) is controlled in a flexible and rapid manner by controlling the adjustable bias voltage (VBias).