Driving Circuit Gate Current Waveform Control for Power Switching
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Solution Overview
Problem
High-speed switching operations in power electronics lead to current ringing, causing noise and accelerating degradation of semiconductor switching elements like MOSFETs and IGBTs, with existing optimization methods not effectively addressing these issues.
Innovation Solution
The implementation of a driving circuit that adjusts the gate current of switching elements in a step-like or ramp-like manner to reduce the voltage across parasitic inductors during switching, either by reducing the gate current before resonance starts or increasing it to cancel resonant currents, thereby minimizing current ringing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the switching speed of semiconductor switching elements is increased to reduce power loss, then power loss is reduced, but current ringing occurs causing noise and accelerating element degradation
Solution Approach 1:
The driving circuit performs preliminary action by adjusting the gate current waveform before the switching event occurs. Specifically, it controls the rate of change of gate voltage (dgate/dt) to predetermined values before turn-on and turn-off, preventing current ringing from occurring in the first place while maintaining high switching speed for reduced power loss
2Productivity
If the switching speed is increased to improve productivity, then productivity is improved, but noise is generated due to current ringing
Solution Approach 1:
The invention applies parameter changes by dynamically adjusting the gate current waveform parameters (specifically dgate/dt) based on the switching state. The driving circuit sets predetermined rates of change for gate voltage before turn-on and turn-off events, which eliminates current ringing and associated noise while preserving high switching speed for improved productivity
3Object-affected harmful factors
If conventional optimization methods based on simulated annealing are used to reduce current ringing, then current ringing is reduced, but the method is complex and not effectively addressing the issues
Solution Approach 1:
Instead of using complex simulated annealing optimization, the invention simplifies the approach by directly setting predetermined parameters for the gate current waveform (dgate/dt values before turn-on and turn-off). This parameter-based approach effectively reduces current ringing while avoiding the complexity of iterative optimization algorithms
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 approach effectively reduces or eliminates current ringing, lowering noise and power loss while extending the lifespan of switching elements by optimizing the gate current waveform based on parasitic capacitances and inductances.
Implementation Method 1
optimizing the gate current waveform based on parasitic capacitances and inductances
Implementation Method 2
reduce the voltage across parasitic inductors during switching
Implementation Method 3
increase it to cancel resonant currents, thereby minimizing current ringing
Data Source
AI summary
In one embodiment, electronic circuitry includes a driving circuit that is configured to: supply a driving current to a control terminal of a first switching element; and increase the driving current in accordance with a first time at which a current flowing through a second switching element connected to a first terminal or a second terminal of the first switching element becomes 0.