Transformerless High Voltage Power Supply with Resonant Frequency Control

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Solution Overview

Problem

Conventional high voltage power supplies, such as those using LC resonant circuits, struggle to adjust output voltage in response to changes in load conditions, leading to potential faults in image formation apparatuses due to fixed voltage settings and frequencies, resulting in either excessive or insufficient voltage application.

Innovation Solution

A high voltage power supply circuit that employs a voltage resonant unit, a multi-stage rectifier circuit, and a voltage controlled oscillator to dynamically adjust output voltage by controlling the frequency of a switching element, allowing for real-time adaptation to load changes without using a transformer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed frequency signal is used to control the LC resonant circuit, then the circuit structure is simple, but the output voltage cannot be adjusted in response to load changes

Engineering Contradiction:
Improveoutput voltage adjustment capabilityVSAvoidcontrol circuit complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the control signal frequency variable instead of fixed. The voltage controlled oscillator dynamically adjusts the clock signal frequency based on feedback from the output voltage, enabling the resonant circuit to adapt to load changes while maintaining relatively simple circuit structure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements feedback by detecting the output voltage and using it to control the frequency of the clock signal through a voltage controlled oscillator. This closed-loop feedback mechanism enables automatic voltage regulation in response to load changes without requiring complex control circuitry.

Inventive Principle:
Principle #23Feedback

2Reliability

If an electromagnetic transformer is used for high voltage generation, then the output voltage is stable, but the power supply size and weight increase

Engineering Contradiction:
Improveoutput voltage stabilityVSAvoidpower supply weight
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent extracts and eliminates the electromagnetic transformer from the high voltage power supply system. By using a transformerless resonant circuit with LC components and rectifiers, it achieves high voltage generation without the heavy transformer, significantly reducing power supply weight while maintaining output stability through frequency-controlled resonance.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies resonance principles by operating the LC circuit at its resonant frequency. The periodic switching of the resonant circuit creates oscillating currents that build up voltage through resonance, enabling stable high voltage generation without requiring a physical transformer.

Inventive Principle:
Principle #18Mechanical vibration

3Reliability

If the clock signal frequency is fixed, then the circuit operation is simple, but the output voltage cannot adapt to load variations causing image formation faults

Engineering Contradiction:
Improveimage formation qualityVSAvoidautomatic voltage regulation
Core Design Contradiction:
ReliabilityVSExtent of automation

Solution Approach 1:

The patent implements automatic voltage regulation through feedback by detecting the output voltage level and using it to adjust the clock signal frequency via a voltage controlled oscillator. This automatic feedback mechanism ensures appropriate voltage levels are maintained under varying load conditions, preventing image formation faults while operating autonomously.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent enables self-service by allowing the power supply to automatically regulate its own output voltage through the feedback-controlled oscillator. The system monitors its own output and adjusts its operating frequency accordingly, ensuring reliable image formation without external intervention or complex control mechanisms.

Inventive Principle:
Principle #25Self-service

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

Enables precise adjustment of output voltage in accordance with load changes, preventing faulty image formation by ensuring appropriate voltage levels are maintained, thereby enhancing the reliability of image formation processes.

Implementation Method 1

a power supply circuit that makes it possible to reduce the size and weight of a high voltage power supply circuit without using an electromagnetic transformer has been proposed... a boosting circuit including a plurality of diodes and capacitors... an LC resonant circuit obtains by amplifying a voltage

Methodology Applied
Scientific EffectLC resonance: Resonance

Implementation Method 2

a boosting circuit including a plurality of diodes and capacitors

Methodology Applied
Scientific EffectRectification: Diode

Data Source

PatentEP2518876B1High-voltage power supply
Publication Date: 2021.07.14 CANON KK
  • EP2518876B1 patent drawingFigure 1
  • EP2518876B1 patent drawingFigure 2
  • EP2518876B1 patent drawingFigure 3

AI summary

In a high voltage power supply that does not use a transformer. An output voltage can be appropriately adjusted in accordance with a load change. A switching element; a voltage resonant circuit that includes an inductor, to which a voltage is applied when the switching element is driven, and a capacitor; a rectifier circuit that includes a capacitor and a diode that output a high voltage in accordance with a resonance operation of the voltage resonant circuit; and a high voltage power supply that performs control in such a manner that a driving frequency of the switching element can be changed in accordance with an output from the rectifier circuit and a control signal used to set an output voltage.