Capacitive Load Charging for Dynamic Motor Braking

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Solution Overview

Problem

Existing electric motor braking systems, particularly those using frictional braking, are inefficient in energy conversion and add weight, while regenerative braking is hindered by unfavorable conditions, limiting its practical application.

Innovation Solution

A hybrid braking system that combines dynamic and regenerative braking by using switching circuitry to connect energy storage devices in parallel for dynamic braking and series configuration for power supply, optimizing energy storage and motor operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If frictional braking is used to slow the motor down, then the motor can be stopped reliably, but weight increases and regular maintenance is required

Engineering Contradiction:

Improvebraking reliabilityVSAvoidbraking system weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent replaces the mechanical frictional braking system with an electrical braking system that uses the motor's back electromotive force to generate braking torque. The switching circuitry connects energy storage devices to the motor terminals, creating an electrical brake that eliminates mechanical friction components, thereby reducing weight while maintaining reliable stopping capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Loss of energy

If regenerative braking is used to convert kinetic energy back into electrical energy, then energy efficiency improves, but unfavorable conditions hinder its practical use

Engineering Contradiction:

Improveenergy waste during brakingVSAvoidapplicability under various conditions

Core Design Contradiction:

Loss of energyVSAdaptability or versatility

Solution Approach 1:

The patent introduces energy storage devices (capacitors or batteries) as an intermediary between the motor and the electrical grid. These devices can absorb regenerative energy when grid connection is unavailable or unsuitable, enabling energy recovery in conditions where traditional regenerative braking cannot operate. The switching circuitry manages the flow of energy between the motor, energy storage devices, and grid, providing versatile operation.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Weight of moving object

If electrical energy storage devices are made smaller and lighter to increase power to weight ratio, then weight decreases, but energy storage capacity is reduced

Engineering Contradiction:

Improveenergy storage device weightVSAvoidenergy storage capacity

Core Design Contradiction:

Weight of moving objectVSQuantity of substance

Solution Approach 1:

The patent merges multiple energy storage devices together through switching circuitry that can connect them in parallel to increase effective capacity. By combining several smaller, lighter devices, the system achieves the required total energy storage capacity while maintaining a lower overall weight compared to using a single large energy storage device. The parallel connection during braking distributes the energy absorption across multiple devices.

Inventive Principle:

Principle #5Merging (Combining)

4Force

If dynamic braking is used to stop the motor, then braking effectiveness is achieved, but kinetic energy is not converted back into electrical energy

Engineering Contradiction:

Improvebraking forceVSAvoidkinetic energy conversion efficiency

Core Design Contradiction:

ForceVSLoss of energy

Solution Approach 1:

The patent converts the previously harmful energy dissipation in dynamic braking into a beneficial energy recovery process. By connecting energy storage devices to the motor terminals during braking, the system captures the kinetic energy that would otherwise be wasted, converting it into electrical energy stored in the capacitors or batteries. This maintains the effective braking force while simultaneously recovering energy for later use.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 reduces waste and weight by efficiently converting kinetic energy into electrical energy, enhancing energy storage and motor performance while minimizing additional weight and space requirements.

Implementation Method 1

Dynamic braking and regenerative braking both use the motor's back electromotive force, which reverses the current flow to stop the rotation

Methodology Applied

Scientific EffectBack electromotive force: Electromagnetic Induction

Implementation Method 2

uses switching circuitry to connect small energy storage devices in parallel, forming a load for dynamic braking. Then it reconnects them in series, to create a power supply for the motor's thrust

Methodology Applied

Scientific EffectCapacitive energy storage: Capacitance

Data Source

PatentUS9793833B1Dynamic braking of an electric motor using capacitive load charging

Publication Date: 2017.10.17 FUJITSU SEMICON LTD

AI summary

The invention disclosed herein is an energy recovery system, for an electric motor, that uses the properties of dynamic braking to directly recharge a capacitive load made up of energy storage devices. The system contains switching circuitry that configures the energy storage devices into a capacitive load when braking is needed. Otherwise, the system configures the energy storage devices into a power supply for regular motor operation.