Resolver Excitation Interface Circuit With Current Protection
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Solution Overview
Problem
There is a need for improved interfaces between machine feedback devices such as resolvers and encoder/Hall sensors and the machine control systems to which they are coupled, with a desire for enhanced functionality and efficient manufacturing.
Innovation Solution
The development of a resolver excitation output stage amplifier with current and voltage protection circuits, along with a multiple device port for coupling resolvers and encoder/Hall sensors to motor control systems, including signal conditioning circuits to enhance signal processing and protection against overcurrent and overvoltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate interface circuits are used for Hall sensors and resolvers, then sensor functionality is complete, but device complexity and bill of materials increases
Solution Approach 1:
The patent combines separate interface circuits for Hall sensors and resolvers into a single integrated interface circuit that can handle both sensor types. This integration reduces the overall number of circuits needed, simplifies the bill of materials, and decreases device complexity while maintaining complete sensor functionality through a unified communication protocol handler.
Solution Approach 2:
The interface circuit is designed with multi-functionality to support both Hall sensor communication (I2C protocol) and resolver signal processing through a single unified interface. This universal design allows the same hardware circuit to perform multiple sensor interface functions, eliminating the need for separate dedicated circuits for each sensor type.
2Measurement precision
If microcontroller CPU resources are heavily utilized for sensor communication, then sensor data is accurately processed, but ac motor control responsiveness deteriorates
Solution Approach 1:
The interface circuit performs preliminary actions by pre-processing sensor data and preparing communication packets before the microcontroller needs to access them. The circuit handles initial data acquisition, filtering, and formatting operations in advance, so that when the microcontroller retrieves the data, it requires minimal processing time, thus maintaining measurement precision without blocking motor control operations.
Solution Approach 2:
The interface circuit acts as an intermediary between the sensors and the microcontroller CPU. It handles the complex communication protocols and data processing tasks independently, translating sensor signals into standardized formats that the microcontroller can quickly process. This mediator role offloads computational burden from the CPU, preserving motor control responsiveness while ensuring accurate sensor data handling.
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
The solution provides enhanced functionality and protection against overcurrent and overvoltage, ensuring reliable operation and efficient coupling of feedback devices to motor control systems, thereby improving the performance and reliability of AC machine systems.
Implementation Method 1
sensors (e.g., Hall sensors) coupled to the rotating member of the ac motor
Implementation Method 2
sensors (e.g., resolvers) coupled to the rotating member of the ac motor
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A resolver excitation output stage amplifier. Disclosed embodiments comprise an amplifier stage and a current protection circuit. The amplifier stage includes one or more amplifier transistors coupled to first and second supply terminals, a timing control terminal and an excitation signal output terminal. The amplifier stage is configured to provide a resolver excitation signal having the excitation frequency at the excitation signal output terminal. The current protection circuit includes one or more protection transistors coupled to the amplifier stage and configured to turn off the one or more transistors of the amplifier stage when current through the one or more transistors of the amplifier stage is greater than a predetermined current value.