Parallel Semiconductor Switching Sequence for Induction Current Suppression
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Solution Overview
Problem
Existing power conversion apparatuses face challenges in reducing switching losses and suppressing erroneous operations of subsidiary semiconductor devices due to increased on-state resistance and induction currents at high temperatures, leading to inadequate temperature control and efficiency.
Innovation Solution
A power conversion apparatus with a semiconductor module comprising a main semiconductor device and a subsidiary semiconductor device connected in parallel, where the control circuit unit controls the switching operations such that the subsidiary device is turned on after the main device, and one switching timing has a faster switching speed than the other, generating an induction current to turn off the subsidiary device during high-speed switching, thereby reducing erroneous operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the subsidiary semiconductor device is used to reduce switching loss, then switching loss reduction is achieved, but erroneous turn-on occurs due to induction current from main current change
Solution Approach 1:
The control circuit unit performs preliminary action by controlling the turn-on timing of the subsidiary semiconductor device to occur after the main semiconductor device is fully turned on, and controlling the turn-off timing of the main semiconductor device to occur after the subsidiary semiconductor device is fully turned off. This sequencing prevents induction current from causing erroneous turn-on of the subsidiary device while maintaining switching loss reduction benefits.
Solution Approach 2:
The control circuit unit uses feedback by monitoring the switching states of both semiconductor devices and adjusting their turn-on and turn-off timings accordingly. This feedback mechanism ensures that the subsidiary device only switches when the main device is in a stable state, preventing erroneous operations while maintaining efficient switching.
2Power
If the main semiconductor device switches are performed, then power conversion is achieved, but induction current turns on the subsidiary semiconductor device erroneously
Solution Approach 1:
The control circuit unit ensures that the subsidiary semiconductor device is turned on only after the main semiconductor device has completed its turn-on process, and the main semiconductor device is turned off only after the subsidiary semiconductor device has completed its turn-off process. This preliminary sequencing action prevents induction current generated during main device switching from erroneously turning on the subsidiary device.
3Speed
If the subsidiary semiconductor device switches are performed simultaneously with main device, then switching speed is improved, but switching loss increases due to voltage across terminals
Solution Approach 1:
The control circuit unit sequences the switching operations so that the subsidiary semiconductor device switches only when the main semiconductor device is already in its on-state, ensuring zero voltage across the subsidiary device during switching. This preliminary timing action maintains fast switching speed while eliminating switching loss.
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 configuration effectively suppresses erroneous operations of the subsidiary semiconductor device by managing induction currents and switching speeds, reducing switching losses and temperature rise, while maintaining efficient power conversion across a wide current range.
Implementation Method 1
an induction current directed to turn off the subsidiary semiconductor device is generated in a control terminal of the subsidiary semiconductor device depending on a temporal change of a main current flowing to the main semiconductor device
Data Source
AI summary
A power conversion apparatus includes a semiconductor module including a semiconductor device and a control circuit unit controlling the semiconductor module. The semiconductor module has main and subsidiary semiconductor devices connected in parallel. The control circuit unit performs control such that the subsidiary semiconductor device is turned on after the main semiconductor device is turned on, and the main semiconductor device is turned off after the subsidiary semiconductor device is turned off. The control circuit unit performs control such that, one of the turn-on and turn-off switching timings has a switching speed faster than that of the other of the switching timings. The semiconductor module is configured such that, at a high-speed switching timing, an induction current directed to turn off the subsidiary semiconductor device is generated in a control terminal of the subsidiary semiconductor device depending on temporal change of a main current flowing to the main semiconductor device.