Parallel Power Module Switching Loss Control
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Solution Overview
Problem
Conventional power modules face challenges in reducing switching losses and prolonging the lifetime of power conversion devices, especially when operated in parallel, due to temperature variations affecting the threshold voltage of switching elements, leading to uneven current distribution and premature deterioration.
Innovation Solution
A power conversion device with multiple sets of power modules, each equipped with a switching element, a third electrode voltage control part, and a temperature detection system that calculates and adjusts the third electrode voltage based on the average operation temperature and individual switching element temperatures to optimize ON/OFF operations and balance current distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a gate voltage which slightly exceeds the threshold voltage is applied to reduce switching loss, then switching loss is reduced, but it becomes difficult to control the ON/OFF operation when temperature changes cause threshold voltage variation
Solution Approach 1:
The patent dynamically adjusts the gate voltage based on the detected threshold voltage to maintain optimal switching performance across temperature variations. By changing the gate voltage parameter in response to temperature-induced threshold voltage changes, the system reduces switching loss while maintaining reliable control
Solution Approach 2:
The patent implements a feedback mechanism where the threshold voltage is detected and used to adjust the gate voltage. This closed-loop control ensures that the gate voltage remains appropriately adjusted despite temperature variations, maintaining both low switching loss and stable control
2Power
If power modules are operated in parallel to increase capacity, then power output is increased, but current distribution becomes uneven due to temperature characteristics causing premature deterioration
Solution Approach 1:
The patent uses feedback control where the threshold voltage of each switching element is detected and used to adjust its gate voltage individually. This ensures balanced current distribution among parallel power modules by compensating for temperature-induced variations in each module's characteristics
Solution Approach 2:
The patent dynamically changes the gate voltage parameter for each switching element based on its detected threshold voltage. This individualized parameter adjustment balances the current distribution across parallel modules, preventing premature deterioration of high-temperature modules
Data Source
AI summary
A power conversion device according to the present invention is provided with two or more sets of power modules each of which includes a switching element and a switching element control circuit having a third electrode voltage control part and a temperature detection part. The power modules PM1, PM2 are connected in parallel to each other. The switching element control circuit includes a temperature comparison part which calculates an average operation temperature of the switching element, and compares an operation temperature of the corresponding switching element and the average operation temperature. The third electrode voltage control part controls a third electrode voltage based on information including an average operation temperature, an operation temperature of the switching element, and a threshold voltage during operation.