Inverter Control Circuit for High-Speed Temperature Estimation
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Solution Overview
Problem
Inverters used in electric vehicles face overheating issues due to heat generation by power semiconductor devices, leading to potential damage or ignition, and existing temperature management methods are inadequate for accurate and rapid detection of overheating in power semiconductor elements.
Innovation Solution
A driving system that calculates the temperature of power semiconductor elements by estimating losses and using thermal resistance values, allowing for high-speed and accurate temperature detection and limiting output torque to prevent overheating, while also considering transient thermal resistance for continuous motor operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If power semiconductor devices are used for high-voltage switching in inverters, then motor driving capability is improved, but heat generation increases leading to overheating risk
Solution Approach 1:
The control circuit calculates the temperature of power semiconductor elements before actual overheating occurs by estimating losses and using thermal resistance values. This preliminary temperature estimation allows the system to take preventive action by limiting output torque before the temperature reaches dangerous levels, thus resolving the contradiction between maintaining high power capability and preventing overheating.
2Reliability
If traditional temperature management methods are used, then device protection is provided, but temperature detection accuracy and speed are insufficient
Solution Approach 1:
The invention replaces traditional mechanical temperature sensors with a calculation-based temperature estimation method. By substituting physical measurement with computational estimation using loss models and thermal resistance values, the system achieves both high measurement precision and fast response speed, while maintaining reliable device protection.
3Productivity
If continuous motor operation at high torque is maintained, then productivity is improved, but transient thermal accumulation causes overheating
Solution Approach 1:
The control circuit continuously calculates the temperature of power semiconductor elements during operation by estimating losses and using thermal resistance values. This feedback mechanism allows the system to monitor transient thermal accumulation in real-time and adjust the output torque accordingly, enabling continuous operation at high productivity levels while preventing overheating through dynamic torque limitation.
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 system effectively prevents overheating and potential damage by accurately estimating temperatures and limiting torque, ensuring safe operation of electric vehicle motors.
Implementation Method 1
Since the inverter performs switching of the high-voltage power supply by the built-in power semiconductor device, heat is generated in operation
Implementation Method 2
the temperature of the power semiconductor element is calculated by calculation based on the loss of each power semiconductor element and a known thermal resistance value
Data Source
AI summary
The temperature of inverters and power semiconductor devices is detected at high speed and with high accuracy. The electronic control circuit includes a vector instruction circuit for calculating an efficiency value of an inverter corresponding to a torque instruction value, and a temperature estimation circuit for estimating a temperature of the power semiconductor element based on the efficiency value of the inverter and a duty cycle for driving the power semiconductor element constituting the inverter.