Delta-Sigma AD Converter with Multi-Filter Segmentation
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Solution Overview
Problem
Existing motor control apparatuses face challenges in optimizing the processing speed and resolution of delta-sigma modulation AD converters for both motor control and abnormal current detection, leading to increased costs and reduced accuracy when using multiple converters or a single converter for both functions.
Innovation Solution
A motor control apparatus with a delta-sigma modulation AD converter featuring multiple digital low-pass filters with unique filter characteristics, optimized for specific purposes, allowing for high-resolution motor drive control and fast abnormal current detection, reducing the need for multiple converters and minimizing size and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single delta-sigma modulation AD converter is used for both motor control and abnormal current detection, then device complexity and cost are reduced, but processing speed and resolution cannot be optimized for both functions simultaneously
Solution Approach 1:
The patent segments the single AD converter into multiple parallel processing channels, each with its own digital low-pass filter having unique filter characteristics. This allows different processing paths for motor control (higher resolution) and abnormal current detection (faster speed), resolving the contradiction between device simplification and functional optimization.
Solution Approach 2:
The patent creates a multi-functional AD converter that can simultaneously perform motor control signal processing and abnormal current detection by incorporating multiple digital low-pass filters with different characteristics. This single device performs multiple functions that would traditionally require separate converters, reducing device complexity while maintaining optimized performance for each function.
2Measurement precision
If multiple delta-sigma modulation AD converters are used to optimize processing speed and resolution for different functions, then processing speed and resolution are improved, but device complexity and cost increase
Solution Approach 1:
The patent merges multiple AD converter functions into a single integrated device by providing multiple digital low-pass filters within one converter. This combining approach achieves the resolution and speed benefits of multiple converters while avoiding the increased device complexity and cost, as all filters share the same delta-sigma modulation front-end.
Solution Approach 2:
The single AD converter is designed with multi-functionality to handle both motor control (requiring high resolution) and abnormal current detection (requiring fast processing) through its multiple digital low-pass filters with unique characteristics, eliminating the need for separate dedicated converters for each function.
3Measurement precision
If the sampling period is extended for high-resolution conversion, then measurement precision is improved, but response speed for abnormal current detection deteriorates
Solution Approach 1:
The patent segments the signal processing into parallel channels with different digital low-pass filters, each optimized for specific requirements. One channel can use longer sampling periods for high-resolution motor control, while another channel processes signals faster for abnormal current detection, resolving the speed-resolution trade-off through functional segmentation.
Solution Approach 2:
The patent changes the filter characteristics (parameters) of the digital low-pass filters to match different processing requirements. By adjusting filter order, cutoff frequencies, and other parameters, the system achieves high resolution for motor control and fast response for abnormal current detection from the same input signal, without extending sampling periods unnecessarily.
Data Source
AI summary
A motor control apparatus includes a power conversion unit which supplies drive power to a motor, a current detection unit which detects the value of a current flowing from the power conversion unit to the motor, a delta-sigma modulation AD converter to which the current value detected by the current detection unit is input as analog data, and which includes a modulator and a plurality of digital low-pass filters and outputs digital data in accordance with the filter characteristics of the respective digital low-pass filters, and a command generating unit which is connected to the digital low-pass filter to be used for motor drive control among the plurality of digital low-pass filters, and which generates a drive command to the power conversion unit by using the digital data output from the motor drive controlling digital low-pass filter.