Power Saving Motor Circuit with Flyback PFC

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing motor driving circuits face high power consumption and design complexity, leading to increased costs, with limitations in power factor correction and precise speed control, particularly due to the use of separate inductors and complex voltage & frequency control schemes.

Innovation Solution

A power saving driving circuit that uses a motor coil as a power factor correcting inductor, charging a capacitor with flyback voltage during normal operation and discharging it during power saving mode, eliminating the need for converters and inverters, and employing a simple resistance dividing circuit for voltage waveform detection to apply sine wave current.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate inductor is used for power factor correction, then power factor correction capability is improved, but device complexity and cost increase

Engineering Contradiction:

Improvepower factor correction capabilityVSAvoidcircuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The motor coil is made to serve dual functions: its primary function of driving the motor and a secondary function as the inductor for power factor correction. By utilizing the motor coil's inherent inductance for both motor operation and power factor correction, the patent eliminates the need for a separate correction inductor, thereby reducing device complexity and cost while maintaining power factor correction capability

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the power factor correction function with the motor coil by connecting the capacitor in parallel with the motor coil. This combination creates a unified system where the motor coil and capacitor work together as an integrated power factor correction mechanism, eliminating separate components and simplifying the overall circuit structure

Inventive Principle:

Principle #5Merging (Combining)

2Measurement precision

If converter and inverter circuits are used for motor control, then speed control precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improvespeed control precisionVSAvoidcircuit complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and removes the complex converter and inverter circuits from the motor control system. By eliminating these complicated voltage and frequency conversion circuits, the patent simplifies the overall system structure while retaining essential motor control functionality through a more straightforward capacitor discharge mechanism

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs a simple capacitor discharge mechanism instead of expensive and complex converter/inverter systems. The capacitor stores energy and provides controlled discharge to the motor, offering a cost-effective alternative that achieves acceptable speed control without requiring sophisticated power conversion circuits

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Adaptability or versatility

If PWM signal is used for voltage & frequency control, then speed control capability is improved, but power consumption and cost increase

Engineering Contradiction:

Improvespeed control capabilityVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent utilizes periodic charging and discharging of the capacitor to control motor operation. The capacitor is charged during specific phases and discharged during others, creating a periodic action pattern that enables speed control without requiring continuous complex PWM signal generation, thereby reducing power consumption while maintaining control capability

Inventive Principle:

Principle #19Periodic action

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 solution reduces power consumption and costs by leveraging the motor coil's current maintaining characteristics, achieving efficient power factor correction and precise speed control while minimizing component damage and complexity.

Implementation Method 1

charging a power factor correction capacitor with a flyback voltage accumulated in a coil of the motor

Methodology Applied

Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 2

operating the motor with a discharge voltage of the capacitor in a power saving mode

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS9172323B2Power saving driving circuit including power factor correction for an induction motor

Publication Date: 2015.10.27 KIM YOUNG JUN

AI summary

A power saving driving circuit for a motor including power factor correction comprises an induction motor; a power factor correction capacitor; a first switching element allowing the motor to operate in a positive sine wave period of an power supply voltage; a diode allowing the power factor correction capacitor to be charged during the first switching element being OFF; a second switching element allowing the motor to operate in a negative sine wave period of the power supply voltage; another diode allowing the power factor capacitor to be charged during the second switching element being OFF; a third switching element connected in parallel to the diode; a fourth switching element connected in parallel to the other diode; and a controller controlling the motor to save power by controlling the third and fourth switching elements when a charged voltage in the power factor correction capacitor reaches a predetermined set value.