Resolver to Digital Converter Time Capture Method
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Solution Overview
Problem
Conventional resolver-to-digital converters require high-speed, high-precision A/D converters to accurately measure peak values of output signals, which can be costly and inefficient.
Innovation Solution
A time measurement-based approach where a reference AC signal is used to detect time intervals between output signals and pre-determined linear signals, allowing for the calculation of rotary angles without the need for high-speed A/D conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-speed, high-precision A/D converters are used to measure peak values of output signals, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces the traditional A/D conversion approach with a time measurement-based approach. Instead of converting analog signals to digital directly using high-speed A/D converters, the system measures time intervals between signal transitions and uses these time measurements to calculate angular displacement. This substitution of the conversion mechanism eliminates the need for complex high-speed A/D converters while maintaining measurement precision.
Solution Approach 2:
The patent changes the measurement parameter from signal amplitude (peak values) to time interval. By measuring the time between specific signal transitions rather than converting signal amplitudes to digital values, the system achieves accurate angular measurement without requiring high-speed A/D conversion. This parameter transformation simplifies the hardware requirements while preserving measurement accuracy.
2Measurement precision
If high-speed, high-precision A/D converters are used to retrieve peak values, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive high-speed A/D converters with simpler time measurement circuitry. The system uses comparators and timers to measure time intervals between signal transitions, which are significantly cheaper and simpler to manufacture than high-speed A/D converters. This substitution maintains measurement precision while dramatically reducing manufacturing cost.
Solution Approach 2:
The patent employs inexpensive time measurement components (comparators, timers, counters) instead of expensive A/D converters. These simpler components can be implemented with standard logic circuits and are much more cost-effective to manufacture, while still achieving the required measurement precision through the time interval measurement method.
3Measurement precision
If conventional A/D conversion approach is used, then angular displacement can be measured, but processing efficiency decreases
Solution Approach 1:
The patent replaces the computationally intensive A/D conversion process with simpler time interval measurement and calculation. By measuring time between signal transitions and using these times to calculate angular displacement through mathematical operations rather than complex analog-to-digital conversion, the system improves processing efficiency while maintaining precision.
Solution Approach 2:
The patent changes the processing approach from signal amplitude conversion to time-based calculation. Measuring time intervals and performing mathematical operations on these time values is computationally simpler and faster than high-speed A/D conversion, thereby improving processing efficiency while preserving measurement accuracy.
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 method enables precise rotary angle measurement with reduced hardware requirements and improved efficiency by converting time intervals into digital signals proportional to sine and cosine values.
Implementation Method 1
A resolver is a kind of rotary position sensor that provides angular measurements by converting angular displacements to electrical signals. In general, a resolver comprises a rotor mechanically coupled to carry the angular displacement of interest to rotate in a stator. A reference winding is located at the rotor driven by a reference signal while two output windings are located at the stator being excited by the reference signal and generate two output signals, respectively, according to the reference signal and the angular displacement of interest.
Data Source
AI summary
A resolver to digital converter system comprises a resolver and a controller. The resolver has a reference winding attached to a rotor, and first and second output windings attached to a stator and coupled to the reference winding. The reference winding is configured to be driven with a reference AC signal having a known frequency and induces first and second output signals from the first and second output windings in response to the reference AC signal. The controller circuit is configured to compare the first and second output signals to first and second linear signals respectively, ascertain first and second time intervals between first and second determined start time points and first and second stop time points where magnitudes of the first and second output signals are substantially equal to magnitudes of the first and second linear signals, respectfully. The controller circuit is further configured to calculate a rotating angle of the resolver based on the first and second time intervals.