Resolver Angle Correction Circuit Using Dynamic Acceleration

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Solution Overview

Problem

Existing angle value correction methods, such as those using pre-prepared tables for speed changes, face challenges in adjusting correction accuracy without increasing circuit size, particularly when changing the resolution of correction values.

Innovation Solution

An angle value correction circuit that includes an acceleration calculation unit to determine the rate of change of rotation speed per interval, an estimated angle calculation unit to calculate rotation angle estimation values assuming uniform acceleration, and a correction value application unit to generate corrected angles without requiring a divider, allowing for flexible correction accuracy without increasing circuit size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a previously prepared table is used for correction values, then the correction process is simplified, but the accuracy of correction cannot be changed after circuit design is completed

Engineering Contradiction:

Improvecorrection process simplicityVSAvoidcorrection accuracy flexibility

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic correction by calculating correction values in real-time based on actual rotation speed and acceleration, rather than using fixed pre-prepared tables. The correction value calculation unit dynamically computes correction values during motor operation, allowing the correction accuracy to adapt to different operating conditions without requiring circuit redesign.

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If the table resolution is changed from 1% to 0.5% change in time of rotation period, then the correction accuracy is improved, but the circuit size increases when using a divider

Engineering Contradiction:

Improvecorrection accuracyVSAvoidcircuit size

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical divider circuit with a software-based calculation approach. Instead of using a physical divider to calculate time changes, the system uses a correction value calculation unit that computes correction values based on rotation speed and acceleration data, achieving higher precision without increasing circuit size.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the approach from fixed table lookup to dynamic parameter-based calculation. Correction values are calculated based on actual rotation speed and acceleration parameters rather than relying on pre-stored tables with fixed resolutions, enabling flexible accuracy adjustment without hardware changes.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If a combination circuit for determination is rebuilt, then the correction accuracy can be adjusted, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:

Improvecorrection accuracyVSAvoidcircuit rebuilding difficulty

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The system uses dynamic calculation of correction values based on real-time rotation speed and acceleration measurements, eliminating the need to rebuild combination circuits for different accuracy requirements. The correction value calculation unit adaptively computes appropriate correction values during motor operation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent uses a software-based correction value calculation that replicates the function of hardware combination circuits through computational algorithms. This virtual copying approach allows accuracy adjustment without physical circuit modifications.

Inventive Principle:

Principle #26Copying

Data Source

PatentUS10969400B2Semiconductor device, angle value correction circuit and method therefor

Publication Date: 2021.04.06 RENESAS ELECTRONICS CORP

AI summary

In order to correct the rotation angle value without an increase in the circuit size, a rotation period measurement unit measures a rotation period of a rotary shaft in which a rotation angle is detected by using a resolver that outputs a signal corresponding to the rotation angle of the rotary shaft. A rotation speed calculation unit calculates the rotation speed of the rotary shaft based on the rotation period. An acceleration calculation unit calculates the rate of change of the rotation speed per interval when a given rotation angle of the rotary shaft is divided into 2n+1 intervals, in which n is an integer of 1 or more. An estimated angle calculation unit calculates the rotation angle estimation value, assuming that the rotary shaft performs a uniform acceleration motion, based on the rotation speed and the rate of change of the rotation speed. A correction value calculation unit calculates the correction value of the rotation angle value converted from the output signal of the resolver. A correction value application unit generates a corrected angle value by applying the correction value to the rotation angle value.