Shift Range Control Device Reducing Motor Hunting

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Solution Overview

Problem

Existing shift range control devices face challenges in improving responsiveness and reducing hunting and overshooting, particularly when using switched reluctance motors, due to the effects of cogging torque and motor stop conditions.

Innovation Solution

A shift range control device that incorporates a feedback control section, stationary phase energization control section, and switching control section, utilizing a permanent magnet DC brushless motor to switch control states based on actual motor angle and speed, switching from feedback control to stationary phase energization control when the angular deviation is within a threshold, to enhance responsiveness and precise motor stopping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If feedback control is used to improve responsiveness, then responsiveness is improved, but hunting and overshooting occur due to cogging torque

Engineering Contradiction:

ImproveresponsivenessVSAvoidhunting and overshooting

Core Design Contradiction:

SpeedVSStability of the object's composition

Solution Approach 1:

The patent employs feedback control using actual motor angle and speed to control motor driving, enabling precise positioning while suppressing hunting and overshooting caused by cogging torque effects

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The control device changes control parameters dynamically by switching between feedback control and stationary phase energization control based on motor state, optimizing both responsiveness and stability across different operating conditions

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If stationary phase energization control is used to reduce power consumption, then power consumption is reduced, but motor stopping accuracy may be compromised

Engineering Contradiction:

Improvepower consumptionVSAvoidmotor stopping accuracy

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The patent uses periodic switching between feedback control and stationary phase energization control, applying energization at appropriate intervals to maintain positioning accuracy while minimizing overall power consumption

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The control device performs preliminary positioning using feedback control before switching to stationary phase energization control, ensuring the motor reaches the target position accurately before entering the low-power holding state

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 configuration improves responsiveness during shift range switching, reduces hunting and overshooting, and ensures accurate motor stopping, while also reducing power consumption by switching to energization off control after a predetermined duration.

Implementation Method 1

utilizing a permanent magnet DC brushless motor to switch control states

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentUS11226037B2Shift range control device

Publication Date: 2022.01.18 DENSO CORP

AI summary

A shift range switching control device for switching a shift range by controlling driving of a motor includes a feedback control section, a stationary phase energization control section, and a switching control section. The feedback control section performs a feedback control based on an actual angle of the motor, and a motor speed. The stationary phase energization control section performs a stationary phase energization control which energizes a stationary phase selected according to the actual angle. The switching control section switches the control state of the motor.