Resolver Signal Converter With ΔΣ ADCs for Stable Angle Tracking

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing digital converters for resolvers face challenges in high-speed and high-precision signal processing due to low conversion speed and precision limitations of successive approximation AD converters, and instability in feedback loops, along with errors caused by phase delays and temperature changes affecting rotational angle calculations.

Innovation Solution

The implementation of ΔΣ AD converters, multiplication units, subtraction, synchronous detection, angular velocity calculation, and rotational angle calculation units, along with a variable delay unit to compensate for phase delays, enables high-speed and high-precision analog-to-digital conversion and stable feedback control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If successive approximation AD converters are used for analog-to-digital conversion, then device complexity is reduced and ease of manufacture is improved, but conversion speed becomes slow (2 to 8 μs) and measurement precision is limited

Engineering Contradiction:

Improveease of manufactureVSAvoidconversion precision

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical successive approximation conversion process with a digital signal processing system using ΔΣ modulation, multiplication units, and synchronous detection. This substitution enables high-speed conversion (about 1 μs) and high precision (16 bits or more) by using digital calculations instead of sequential analog comparison steps.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If successive approximation AD converters are used, then conversion speed is slow (2 to 8 μs), but device complexity is low and ease of manufacture is improved

Engineering Contradiction:

Improveease of manufactureVSAvoidconversion speed

Core Design Contradiction:

Ease of manufactureVSSpeed

Solution Approach 1:

The patent replaces the mechanical successive approximation conversion process with a digital signal processing system using ΔΣ modulation, multiplication units, and synchronous detection. This substitution enables high-speed conversion (about 1 μs) by using digital calculations instead of sequential analog comparison steps.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If feedback loop uses only integrator units for stability, then reliability is improved, but the system becomes unstable due to phase delays and temperature changes

Engineering Contradiction:

Improvefeedback loop stabilityVSAvoidrotational angle calculation precision

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent introduces a variable delay unit that dynamically adjusts the delay time based on temperature changes and phase delays. This dynamic adjustment maintains feedback loop stability while compensating for environmental variations, preventing rotational angle calculation errors without requiring the feedback loop to be overly conservative.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the delay time parameter in the feedback loop based on temperature and phase delay conditions. By adjusting this parameter dynamically, the system maintains stability and precision under varying operating conditions, resolving the contradiction between stability and precision.

Inventive Principle:

Principle #35Parameter changes

4Device complexity

If delay time compensation is not implemented, then device complexity is low, but rotational angle calculation precision is reduced due to phase shifts in synchronous detection

Engineering Contradiction:

Improvedevice complexityVSAvoidrotational angle precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS8188896B2Digital converter for processing resolver signal

Publication Date: 2012.05.29 KK TOSHIBA

AI summary

According to one embodiment, a digital converter is provided to process output signals of a resolver attached to a rotating apparatus. These output signals are converted into digital signals by ΔΣ AD converters. Multiplication units receive the digital signals outputted from the ΔΣ AD converters. A subtraction unit subtracts the outputs of the multiplication units. A synchronous detection unit detects the output of the subtraction unit based on a synchronization signal synchronously. An angular velocity calculation unit adjusts a proportional gain of an output of the synchronous detection unit, compensates the phase thereof, and calculates the angular velocity of the rotating apparatus. A rotational angle calculation unit calculates a rotational angle by integrating the angular velocity. Cosine and sine output units output a cosine and a sine corresponding to the obtained rotational angle to the multiplication units, respectively.