PCB-Based Power Transistor Temperature Sensing for Inverter Derating
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Solution Overview
Problem
Power transistors in inverters, particularly those in DC/DC conversion circuits and inverter circuits, are prone to damage due to high working temperatures, which can lead to inverter failure and safety risks, necessitating effective temperature monitoring and power control to ensure safe and efficient operation.
Innovation Solution
A power transistor temperature detection circuit with a temperature detector and sampling controller is implemented on the same PCB as the power transistor, allowing for fine-grained temperature monitoring and independent power control of each DC/DC conversion circuit based on temperature feedback, with different threshold settings for varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If power transistors operate at high frequency for long time to ensure high efficiency, then energy conversion efficiency is improved, but temperature increases causing reliability deterioration
Solution Approach 1:
The temperature detector is installed on the same PCB as the power transistor to perform preliminary temperature monitoring before damage occurs. This allows the system to detect temperature changes in advance and trigger protective measures, preventing reliability deterioration while maintaining high efficiency operation
Solution Approach 2:
The sampling controller receives temperature feedback from the detector and adjusts the output power of the DC/DC conversion circuit accordingly. This closed-loop feedback mechanism ensures the power transistor operates within safe temperature ranges while maximizing energy conversion efficiency
2Productivity
If output power of DC/DC conversion circuit is increased to meet energy demand, then productivity is improved, but temperature of power transistor exceeds threshold causing reliability to worsen
Solution Approach 1:
The sampling controller dynamically adjusts the output power of the DC/DC conversion circuit based on real-time temperature feedback. When temperature is within threshold, full power is allowed for maximum productivity; when temperature approaches threshold, power is reduced to ensure reliability, creating a dynamic balance between productivity and safety
3Reliability
If temperature monitoring and power control measures are implemented to ensure safety, then reliability is improved, but device complexity increases
Solution Approach 1:
The temperature detector is integrated on the same PCB as the power transistor, merging the monitoring function into the existing circuit board structure. The sampling controller uses the existing control architecture to implement temperature-based power adjustment, reducing the need for separate monitoring systems and minimizing additional complexity while improving 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 ensures safe and stable operation of power transistors by accurately detecting and controlling output power, reducing the risk of overheating and extending the lifespan of inverters while maintaining efficiency.
Implementation Method 1
The temperature detection unit is disposed in a one-to-one correspondence with the first power transistor, and is configured to detect a temperature of the first power transistor, and feed back temperature information of the first power transistor to the sampling controller
Data Source
AI summary
In each direct current (DC)/DC conversion circuit and an inverter circuit in an inverter, one temperature detection unit is correspondingly configured for at least one power transistor in each circuit, and the temperature detection unit is disposed near the power transistor. A temperature of the power transistor is detected, to implement detection on the temperature of the power transistor. After receiving temperature information fed back by the temperature detection unit, a sampling control unit controls, based on a preset condition, a corresponding DC/DC conversion circuit to perform derating.