Motor Control via Coil Inductance Measurement
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Solution Overview
Problem
Existing motor control systems for image forming apparatuses require temperature sensors to manage motor performance, which occupy additional space and increase control time, especially when detecting motor temperature changes.
Innovation Solution
A motor control apparatus that estimates the temperature of a rotor by measuring physical quantities related to coil inductance changes during specific excitation phases without using a temperature sensor, allowing for parameter value adjustments based on the estimated temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is arranged in the motor to detect temperature, then motor temperature can be accurately measured, but extra space within the apparatus is required and control time increases
Solution Approach 1:
The patent replaces the physical temperature sensor with an electrical measurement system. By measuring the inductance of motor coils, which changes with temperature due to thermal expansion and material property changes, the system substitutes direct thermal sensing with electrical property detection. This eliminates the need for physical temperature sensors while providing temperature information for control purposes.
Solution Approach 2:
The patent introduces inductance measurement as an intermediary parameter to indirectly detect temperature. Instead of directly measuring temperature with a sensor, the system measures coil inductance (an electrical property that changes with temperature) and uses this intermediate measurement to infer temperature conditions for motor control adjustments.
2Reliability
If the temperature of the motor is detected after activation, then temperature-based control can be implemented, but the time required for motor control becomes long
Solution Approach 1:
The patent performs inductance measurements during motor operation rather than requiring a separate temperature detection phase. By continuously monitoring coil inductance during normal motor activation and operation, the system obtains temperature information in real-time without adding preliminary detection steps, thus maintaining fast control response while enabling temperature-based adjustments.
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
Enables effective motor control without the need for temperature sensors, reducing space requirements and shortening control time while maintaining motor performance by accurately estimating rotor temperature and adjusting control parameters accordingly.
Implementation Method 1
measure a physical quantity which changes in accordance with an inductance of at least one of a plurality of coils configuring the plurality of excitation phases
Data Source
AI summary
A motor control apparatus excites an excitation phase targeted for excitation among a plurality of excitation phases of a motor. The motor control apparatus, in a state in which a rotor of the motor is stopped, excites an excitation phase corresponding to a stop position of the rotor among the plurality of the excitation phases, and measures a physical quantity which changes in accordance with an inductance of at least one of a plurality of coils configuring the plurality of excitation phases. The motor control apparatus estimates a temperature of the rotor from a measurement value of the measured physical quantity, and decides a parameter value for control of the motor based on the estimated temperature.