Motor Drive Element Temperature Estimation for Range Switching
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Solution Overview
Problem
Existing motor control devices lack temperature detection capabilities, leading to reduced range switching capabilities in high-temperature environments and difficulty in directly measuring the temperature of driving elements, necessitating conservative switching limits.
Innovation Solution
A motor control device with a drive circuit and controller that includes a drive state acquisition unit, reference temperature calculation unit, and temperature estimation unit to estimate driving element temperature based on drive states and reference temperatures, updating the estimated temperature accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temperature detection is not performed and conservative switching limits are set, then reliability is ensured in high-temperature environments, but the number of range switches is reduced
Solution Approach 1:
The patent replaces direct temperature detection (mechanical/sensor-based approach) with a calculation-based temperature estimation method. The control device calculates the drive element's temperature by considering motor drive states, duty cycles, and heat generation characteristics, substituting physical temperature sensors with a computational model that achieves the same protective function without limiting operational capability
Solution Approach 2:
The patent introduces an intermediate calculation process that mediates between motor drive states and temperature protection. Instead of directly detecting temperature or imposing conservative limits, the system uses duty cycle accumulation and heat generation calculations as an intermediary to estimate temperature and make informed control decisions, enabling both reliability and operational flexibility
2Measurement precision
If direct temperature detection of drive element is attempted, then accurate temperature measurement is achieved, but installation complexity increases due to installation constraints
Solution Approach 1:
The patent extracts the temperature measurement function from the physical domain to the computational domain. Instead of installing temperature sensors on or near the drive element (which would increase installation complexity), the system extracts temperature information by calculating it from readily available motor drive state data, duty cycles, and heat generation characteristics, achieving accurate temperature measurement without additional hardware installation
Solution Approach 2:
The patent creates a computational copy of the temperature information rather than physically measuring it. By modeling heat generation based on motor drive states and duty cycles, the system generates a virtual temperature representation that accurately reflects the drive element's thermal state without requiring physical contact or proximity to the drive element, thus avoiding installation constraints
Data Source
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AI summary
The motor control device (40) has a drive circuit (41) and a controller (50). The drive circuit (41) includes a driving element that switches current supply to a motor (10). The controller (50) includes a state acquirer (53) that acquires a driving state of the motor (10), a reference temperature calculation unit (581) that calculates an ambient temperature of the driving element as a reference temperature based on the detection value of a temperature sensor (45), and a temperature estimation unit (582) that estimates an element temperature, which is a temperature of the driving element. The temperature estimation unit (582) estimates the rise in temperature based on the motor's driving state and the reference temperature when it is determined that the motor is being driven, and estimates the drop in temperature based on the reference temperature when it is determined that the motor is not being driven. The temperature estimation unit (582) updates the estimated value of the element temperature based on the rise or drop in temperature.