Motor Control Device Phase Switching for Heat Suppression
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Solution Overview
Problem
Conventional motor control devices experience heat generation issues when switching current supply phases, leading to reduced convenience and motor inactivity during heat generation states, as they limit power supply to prevent failure.
Innovation Solution
A motor control device with a control circuit that switches current supply phases based on encoder pulse signals, using a predetermined number of phase changes in acceleration, deceleration, and stationary rotation ranges, with a lower switching number in stationary conditions to minimize heat generation and maintain convenience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power supply to the motor is limited when heat generation state is detected, then heat generation is suppressed and motor failure is prevented, but convenience is lowered and the motor cannot rotate even when the driver manipulates the shift lever
Solution Approach 1:
The patent dynamically adjusts the current supply phase switching strategy based on the motor's operational state (acceleration, stationary rotation, or deceleration). During acceleration and deceleration, the control circuit maintains higher switching frequencies to ensure proper motor control, while during stationary rotation it reduces switching frequency to minimize heat generation. This dynamic adaptation allows the system to maintain convenience during critical operations while suppressing heat during less demanding phases.
Solution Approach 2:
The control circuit changes the parameter of current supply phase switching frequency based on the motor's rotation speed and operational phase. By monitoring whether the motor is in acceleration, stationary rotation, or deceleration state, the system adjusts the switching number of current supply phases accordingly, optimizing the balance between motor control performance and heat generation suppression.
2Measurement precision
If the current supply phase is switched over frequently to maintain precise motor control, then motor control precision is improved, but heat generation increases
Solution Approach 1:
The system dynamically adjusts the switching frequency of current supply phases based on the motor's operational state. During acceleration and deceleration when precise control is critical, the switching frequency is maintained at higher levels. During stationary rotation when precision requirements are lower, the switching frequency is reduced to minimize heat generation, thus dynamically optimizing the balance between control precision and thermal management.
Solution Approach 2:
The control circuit changes the switching parameter (number of current supply phase switches per predetermined angular rotation) based on the motor's rotation speed and operational phase. This parameter adaptation allows the system to use higher switching numbers during acceleration/deceleration for precise control and lower switching numbers during stationary rotation to reduce heat, effectively managing the trade-off between precision and thermal output.
3Temperature
If the switching number of current supply phase is reduced in stationary rotation range, then heat generation is suppressed, but motor responsiveness may be affected
Solution Approach 1:
The control circuit dynamically adjusts the switching number based on the motor's operational state, maintaining higher switching numbers during acceleration and deceleration when responsiveness is critical, and reducing switching numbers during stationary rotation when heat suppression is the priority. This dynamic adjustment ensures that motor responsiveness is preserved when needed while allowing heat suppression during less critical phases.
Solution Approach 2:
The system changes the switching parameter (number of current supply phase switches) based on rotation speed thresholds and operational ranges. By maintaining appropriate switching numbers during acceleration and deceleration while reducing them during stationary rotation, the system optimizes the balance between heat generation suppression and motor responsiveness, ensuring that responsiveness is maintained during critical operational transitions.
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 effectively suppresses heat generation and power consumption while maintaining motor functionality, avoiding the inconvenience of reduced power supply during acceleration and deceleration, and managing load increases by adjusting switching numbers based on rotation speed thresholds.
Implementation Method 1
an encoder for outputting a pulse signal in synchronization with a rotation of a rotor of the motor
Implementation Method 2
a driving circuit for rotationally driving the rotor to a target rotation position by switching over the current supply phase
Data Source
AI summary
A motor control device is provided with a control circuit and a driving circuit. The control circuit switches over a current supply phase of the motor in a predetermined angular rotation of the rotor a first switching number of times in an acceleration range. The control circuit switches over the current supply phase of the motor in the predetermined angular rotation of the rotor a second switching number of times in a stationary rotation range in a specific condition that the rotation speed of the rotor is between a predetermined first threshold value and a predetermined second threshold value. The control circuit sets the second switching number to be smaller than the first switching number. In the acceleration range, the switching number is relatively large and hence a sufficient driving torque is applied to the rotor. In the stationary rotation range, the switching number is relatively small and hence the control circuit 61 needs to operate less, a current supply period for the motor is shortened and heat generation is suppressed.