Phase Adjusting Circuit for Inverter Resonance Tracking

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Solution Overview

Problem

Existing phase adjusting circuits for inverter systems face inefficiencies due to gaps between oscillation frequencies and resonant frequencies, particularly when resonant frequencies change significantly, leading to reduced conversion efficiency.

Innovation Solution

A phase adjusting circuit utilizing a phase locked loop (PLL) with a filter circuit and a delay circuit, allowing for precise frequency adjustment across a wide range by varying the resistance values of variable resistance elements to synchronize the phase of the reference signal with the resonant current, ensuring accurate phase matching and minimizing frequency errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional phase adjusting circuit is used, then the circuit structure is simple, but the frequency adjustment precision deteriorates when resonant frequency changes significantly

Engineering Contradiction:
Improvefrequency adjustment precisionVSAvoidcircuit structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The phase adjusting circuit is segmented into multiple independent modules: a phase comparator for detecting phase differences, a voltage-controlled oscillator for frequency adjustment, a low-pass filter for signal processing, and a voltage amplifier for signal conditioning. This modular segmentation allows each component to be optimized for its specific function, achieving high frequency adjustment precision across wide resonant frequency ranges while maintaining reasonable circuit complexity through functional decomposition

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The circuit implements a phase-locked loop feedback mechanism where the phase comparator continuously monitors the phase difference between the reference signal and the resonant frequency signal, and feeds this information back to the voltage-controlled oscillator. This closed-loop feedback system automatically corrects frequency deviations, enabling precise frequency tracking and adjustment even when resonant frequency changes significantly, thereby resolving the contradiction between precision and complexity

Inventive Principle:
Principle #23Feedback

2Loss of energy

If the oscillation frequency is adjusted to follow resonant frequency, then conversion efficiency is improved, but phase difference and frequency errors increase when resonant frequency changes largely

Engineering Contradiction:
Improveconversion efficiencyVSAvoidphase matching accuracy
Core Design Contradiction:
Loss of energyVSMeasurement precision

Solution Approach 1:

The phase comparator provides continuous feedback on phase differences between the oscillation signal and the resonant frequency signal. This feedback mechanism enables real-time detection and correction of phase mismatches, allowing the system to maintain accurate phase locking and frequency synchronization even when resonant frequency changes significantly, thus preventing energy loss while maintaining precision

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The circuit replaces mechanical or simple electronic frequency adjustment mechanisms with an electronic phase-locked loop system. The PLL uses electronic signal processing and feedback control to achieve precise frequency and phase synchronization, substituting crude mechanical tuning with sophisticated electronic control that maintains accuracy across wide frequency ranges, thereby resolving the trade-off between efficiency and precision

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

3Adaptability or versatility

If a phase locked loop circuit is used for frequency adjustment, then frequency tracking capability is improved, but the circuit complexity increases

Engineering Contradiction:
Improvefrequency tracking capabilityVSAvoidcircuit complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The phase locked loop is divided into four distinct functional segments: the voltage-controlled oscillator for frequency generation, the phase comparator for error detection, the low-pass filter for error signal processing, and the voltage amplifier for signal conditioning. This segmentation allows each component to be independently optimized and implemented using standard electronic circuits, reducing overall complexity while maintaining excellent frequency tracking capability across varying resonant frequencies

Inventive Principle:
Principle #1Segmentation

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

The proposed solution enables high-precision frequency adjustment, maintaining conversion efficiency of 85% or higher across the entire frequency range, significantly improving the performance of inverter circuits and power supply systems by eliminating phase differences and errors.

Implementation Method 1

a phase locked loop (PLL) circuit that outputs a signal based on a phase difference between a reference signal and a feedback signal

Methodology Applied
Scientific EffectPhase locked loop:

Implementation Method 2

a filter circuit that delays a phase of the reference signal in a case where an oscillation frequency of a circuit main body falls in a first level

Methodology Applied
Scientific EffectRC filtering: Filter (electronic)

Implementation Method 3

a delay circuit that delays the output signal in a case where the oscillation frequency of the circuit main body falls in a second level that is lower than the first level

Methodology Applied
Scientific EffectRC time delay: Filter (electronic)

Data Source

PatentEP3382883B1Phase adjusting circuit, inverter circuit, and power supply system
Publication Date: 2020.07.29 SUMIDA CORP
  • EP3382883B1 patent drawingFigure 1
  • EP3382883B1 patent drawingFigure 2
  • EP3382883B1 patent drawingFigure 3

AI summary

[Problem] Provided is a phase adjusting circuit that can highly precisely adjust frequencies throughout the entire frequency range to be dealt with. [Solving Means] Included is a PLL circuit 13 including: a reference-signal input terminal 13a from which a reference signal Sr is input; a feedback-signal input terminal 13b from which a feedback signal Sf is input; and an output terminal 13c from which an output signal So based on a phase difference between the reference signal Sr and the feedback signal Sf is output. In addition, further included is a filter circuit 25 connected to the reference-signal input terminal 13a and the output terminal 13c, and causing a phase of the reference signal Sr to be delayed in the case where the oscillation frequency of an inverter circuit 3 including the PLL circuit 13 falls in a high range, and a delay circuit 27 connected to the output terminal 13c, and causing the output signal So to be delayed in the case where the oscillation frequency of the inverter circuit 3 falls in a low range that is lower than the high range.