Motor Controller Sleep Mode for Power Reduction

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Solution Overview

Problem

Conventional motor controllers that calculate the estimated temperature of a motor to prevent overheating continue to consume power even when the motor is stationary, increasing the load on vehicle-mounted batteries and requiring continuous processing to ensure accurate temperature estimation upon restart.

Innovation Solution

A motor controller with a mode switching mechanism that transitions between a normal operation mode and a sleep mode to reduce power consumption, allowing the estimated temperature calculation to be performed intermittently during a sleep mode, thereby minimizing continuous power usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the microcomputer continuously calculates the estimated temperature of the motor even when the motor is stationary, then the accuracy of temperature estimation upon restart is maintained, but the electric power consumption of the vehicle-mounted battery increases

Engineering Contradiction:

Improvetemperature estimation accuracyVSAvoidelectric power consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The microcomputer performs temperature estimation calculations at periodic intervals rather than continuously. When the motor is stationary, the system switches to a low-power mode where temperature calculation is performed only at predetermined intervals, significantly reducing power consumption while maintaining adequate temperature monitoring capability for safe motor restart operation

Inventive Principle:

Principle #19Periodic action

2Reliability

If the protection element is arranged near the motor, then the motor is protected from being burned, but the size of the motor is enlarged

Engineering Contradiction:

Improvemotor protectionVSAvoidmotor size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent replaces physical protection elements (such as thermal fuses or thermal switches) with an electronic temperature estimation system. The microcomputer calculates motor temperature based on voltage, current, and time parameters, eliminating the need for physical protection elements near the motor, thereby maintaining protection functionality while reducing motor size

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS7321213B2Motor controller

Publication Date: 2008.01.22 DENSO CORP

AI summary

A motor controller is provided with: an estimated temperature calculating means that calculates an estimated temperature of a motor; and a control unit that can perform a driving control of the motor only when the estimated temperature is not larger than a predetermined value. A mode switching means switches the control unit and the estimated temperature calculating means between in a normal operation mode in which they can drive the motor and in a sleep mode in which electric power consumption thereof is smaller than in the normal operation mode in accordance with a predetermined condition while the motor is stationary. An activating means activates the estimated temperature calculating means in the sleep mode for a predetermined active time every time a predetermined sleep time is elapsed.