Brushless Motor Switch Control for Smooth Torque Transition

Solution Overview

Problem

Conventional methods for controlling power generation in brushless permanent magnet kinetic mechanisms, such as electric motors and generators, result in inefficient energy conversion and unsmooth torque behavior, leading to dangerous riding conditions due to abrupt changes in torque and power generation.

Innovation Solution

A method employing a control circuit with parallel switch groups and pulse width modulation for ON/OFF switching, allowing the rotor to effectively convert kinetic energy into electrical energy even at low rotational speeds, and using current detection elements processed by a microprocessor to control torque through electric current, ensuring maximum energy conversion and smooth operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional voltage duty control is used to control power generation, then the control circuit is simple, but the torque changes abruptly causing dangerous riding conditions

Engineering Contradiction:

Improvecontrol circuit complexityVSAvoidriding safety

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent applies dynamics by making the switch control strategy adaptive based on operating conditions. The controller dynamically adjusts which switches are controlled (first switch group vs second switch group) based on rotor speed and power generation requirements, enabling smooth torque transition from motor to generator mode without abrupt changes that would compromise riding safety

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent segments the switch control into two independent groups: a first switch group (Q1, Q3, Q5) and a second switch group (Q2, Q4, Q6). This segmentation allows independent control strategies for each group, enabling the first group to maintain motor mode operation while the second group enables power generation, thereby avoiding abrupt torque changes and ensuring riding safety

Inventive Principle:

Principle #1Segmentation

2Productivity

If both upper and lower side switches are simultaneously set ON for charging, then the charging path is established, but the back EMF and power storage device voltage are in series requiring increased inductor voltage leading to poor power generation

Engineering Contradiction:

Improvecharging efficiencyVSAvoidpower generation efficiency

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent segments the switch control into two independent groups: a first switch group (Q1, Q3, Q5) and a second switch group (Q2, Q4, Q6). This segmentation allows independent control strategies for each group, enabling the first group to maintain motor mode operation while the second group enables power generation, thereby avoiding abrupt torque changes and ensuring riding safety

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies dynamics by making the switch control strategy adaptive based on operating conditions. The controller dynamically adjusts which switches are controlled (first switch group vs second switch group) based on rotor speed and power generation requirements, enabling smooth torque transition from motor to generator mode without abrupt changes that would compromise riding safety

Inventive Principle:

Principle #15Dynamics

3Productivity

If immediately increased from no power generated to 50% duty of power generation, then the power generation duty is increased, but the initial torque is abruptly increased to maximum and then lowered causing abrupt stop similar to emergency braking

Engineering Contradiction:

Improvepower generation dutyVSAvoidriding smoothness

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The patent applies preliminary action by pre-establishing the first switch group control configuration before transitioning to power generation mode. The controller prepares the circuit topology in advance by keeping Q1, Q3, Q5 controlled while enabling Q2, Q4, Q6 for power generation, ensuring that torque transitions are smooth and predictable rather than abrupt, thereby maintaining riding comfort and safety

Inventive Principle:

Principle #10Preliminary 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 approach achieves efficient power generation and smooth torque control, enabling the conversion of kinetic energy into electrical energy with high efficiency and preventing abrupt changes in torque, thereby enhancing the safety and stability of electric motor operation.

Implementation Method 1

the rotor with a brushless permanent magnet can effect conversion between kinetic energy and electrical energy even at a low rotational speed

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the induced voltage VL of the inductor is L(di/dt)

Methodology Applied

Scientific EffectInductance: Inductor

Implementation Method 3

the back electromotive force (back EMF) kew

Methodology Applied

Scientific EffectBack EMF: Electromagnetic Induction

Data Source

PatentUS8405366B2Method for controlling generation of electrical power

Publication Date: 2013.03.26 ADLEE POWERTRONIC

AI summary

A method is provided for controlling power generation. A control circuit is employed to control first and second switches of each of multiple switch groups of a drive circuit so that the first switches are kept in OFF state while the second switches are each switched between ON and OFF states at each given time point. With the second switches of the switch groups alternately switched ON/OFF, electrical power is fed to a circuit system, which includes a power storage device or an application device of loading.