Motor Temperature Estimation in Nonvolatile Memory
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Solution Overview
Problem
Existing techniques for estimating and storing motor temperature in nonvolatile memory lead to frequent writing, which shortens the memory's lifetime, even when the temperature change is significant multiple times in a short period.
Innovation Solution
Implementing a controller that calculates the motor's estimated temperature based on its driving amount and condition, and schedules writes to nonvolatile memory differently, writing when the temperature increases more frequently and decreases less frequently, with specific time intervals for each scenario.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature information is written into nonvolatile memory whenever the temperature change amount is greater than or equal to a predetermined amount, then the temperature estimation accuracy is maintained, but the writing frequency becomes excessively high which shortens the nonvolatile memory lifetime
Solution Approach 1:
The patent applies dynamics by making the writing interval adaptive rather than fixed. The controller dynamically adjusts the writing interval based on the current temperature change amount: when temperature changes rapidly (large temperature change amount), the writing interval is shortened to maintain accuracy; when temperature is stable (small temperature change amount), the writing interval is extended to reduce wear on the nonvolatile memory. This dynamic adjustment resolves the contradiction between maintaining temperature estimation accuracy and preserving memory lifetime.
Solution Approach 2:
The patent changes the parameter of writing interval based on temperature conditions. Instead of using a constant writing threshold, the system varies the writing interval parameter according to the magnitude of temperature changes detected. This parameter change allows the system to optimize between two conflicting requirements: frequent writing for accuracy and infrequent writing for memory preservation, by adapting the writing frequency to actual temperature behavior patterns.
2Loss of time
If temperature information is written into nonvolatile memory at constant intervals, then the temperature data is regularly updated, but the writing frequency is too high which excessively shortens the nonvolatile memory lifetime
Solution Approach 1:
The patent implements periodic action with variable periods. Instead of constant-interval writing, the system performs temperature information writing at periodic intervals that are determined by current temperature conditions. The writing interval is periodically reassessed and adjusted based on the temperature change amount, creating a flexible periodic pattern that maintains data freshness when needed while reducing unnecessary writes during stable temperature periods, thus extending memory lifetime.
Solution Approach 2:
The patent applies partial action by writing temperature information only when necessary rather than at every constant interval. The system performs partial updates based on whether the temperature change amount justifies a write operation. This selective writing approach reduces the total number of write operations to the nonvolatile memory while still maintaining adequate temperature data freshness, thereby resolving the contradiction between regular updates and memory preservation.
Data Source
AI summary
An electronic apparatus includes a motor, a controller, and a nonvolatile memory. The controller executes: an estimated-value calculating process for calculating an estimated value of a temperature of the motor; a first writing process for writing the calculated estimated value into the nonvolatile memory in a situation in which the calculated estimated value increases; and a second writing process for writing the calculated estimated value into the nonvolatile memory in a situation in which the calculated estimated value decreases. The controller executes the first writing process when at least a first time has elapsed after the estimated value is written in the nonvolatile memory. The controller executes the second writing process when at least a second time has elapsed after the estimated value is written in the nonvolatile memory. The first time is less than the second time.