Motor Control Device Voltage Optimization for Thermal Management
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Solution Overview
Problem
The existing motor control devices experience significant heat generation and power losses in semiconductor elements due to increased input voltage and current, leading to inefficient operation and potential overheating.
Innovation Solution
A motor control device that includes an inverter, a converter, a temperature acquisition part, and a control device to calculate and set an optimal or lowest input voltage based on motor rotational speed and torque settings, minimizing heat generation by adjusting the target input voltage based on measured or estimated semiconductor element temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the input voltage is increased to improve motor operation efficiency, then the motor can operate more efficiently, but the heat generation and power losses in semiconductor elements increase
Solution Approach 1:
The patent implements dynamic adjustment of the target input voltage based on real-time temperature feedback from semiconductor elements. The control device continuously monitors element temperatures and adjusts the target input voltage dynamically, rather than using a fixed voltage setting. This allows the system to optimize motor operation efficiency while preventing excessive heat generation in semiconductor elements by lowering the voltage when temperatures rise.
Solution Approach 2:
The patent employs a feedback mechanism where the temperature acquisition part measures element temperatures and feeds this information back to the control device. The control device uses this temperature feedback to adjust the target input voltage, creating a closed-loop control system that balances motor efficiency with semiconductor element temperature management, thereby reducing power losses when temperatures become excessive.
2Power
If the current passing through the inverter or converter is increased to improve power output, then the motor torque increases, but the heat generation in semiconductor elements becomes large
Solution Approach 1:
The system dynamically adjusts the target input voltage based on real-time temperature conditions of semiconductor elements. When element temperatures rise due to high current operation, the control device lowers the target input voltage, which subsequently reduces the current through the inverter and converter, thereby controlling heat generation while still meeting torque requirements through optimized voltage control.
Solution Approach 2:
The patent changes the operating parameters of the power conversion system by adjusting the target input voltage based on temperature conditions. This parameter change approach allows the system to operate at optimal voltage levels that balance power output requirements with thermal management, preventing excessive heat generation in semiconductor elements while maintaining adequate motor torque.
3Loss of energy
If the target input voltage is set to optimal value for efficiency, then energy loss is minimized, but semiconductor elements may overheat under certain operating conditions
Solution Approach 1:
The patent implements a feedback-based temperature management system where the temperature acquisition part continuously monitors semiconductor element temperatures and feeds this information to the control device. The control device adjusts the target input voltage based on this feedback, ensuring that energy efficiency is maintained while preventing semiconductor element overheating, thus improving reliability without significantly compromising energy loss minimization.
Solution Approach 2:
The system transitions from a static optimal voltage setting to a dynamic voltage adjustment mechanism that responds to real-time temperature conditions. This dynamic approach allows the target input voltage to be optimized for energy efficiency under normal conditions while automatically adjusting to prevent overheating when temperature limits are approached, thereby maintaining both energy efficiency and component reliability.
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
This solution effectively reduces heat generation and power losses in semiconductor elements, enhancing the efficiency and reliability of motor operation by optimizing input voltage settings according to temperature conditions.
Implementation Method 1
an inverter that is configured to convert direct current electric power output from the direct current power supply into alternating current electric power
Implementation Method 2
a converter that is configured to convert a direct current voltage from the direct current power supply into an input voltage, which is a voltage input to the inverter
Implementation Method 3
a motor configured to convert electric power into mechanical power
Data Source
AI summary
A motor control device includes an optimal voltage calculation part configured to calculate an input voltage that is a lowest total of electric power losses generated by an inverter, a motor and a converter, a lowest voltage calculation part configured to calculate a lowest value of the input voltage required at a motor operating point, and a target value setting part configured to set any one of the optimal input voltage and the lowest input voltage as the target input voltage, and the target value setting part sets the lowest input voltage lower than the optimal input voltage to the target value when the element temperature of the inverter and the converter is equal to or greater than a predetermined value.