Current-Type Gate Driver Reduces Switching Loss in Power Converters
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Solution Overview
Problem
Conventional power converting apparatuses face challenges in reducing switching loss and element stress due to increasing operating voltages and currents, particularly with Wide Band Gap devices, leading to increased component stress and heat generation, and require complex circuits that increase volume and cost.
Innovation Solution
A power converting apparatus that uses a control current to sink current from the gate terminal during partial sections of the turn-on and turn-off operations of switching elements, with a gate drive unit comprising a current source unit, a sink current unit, and a control current controller to generate a gate driving signal with multiple current levels, allowing for efficient switching operations and reduced heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional voltage-type gate driver is used to drive switching elements, then the structure is simple and reliability is excellent, but switching loss increases and element stress increases as operating voltage and current increase
Solution Approach 1:
The patent changes the fundamental operating parameter of the gate driver from voltage-type to current-type. The gate driver circuit generates a gate driving signal based on current characteristics rather than voltage characteristics. This parameter change enables the circuit to actively control the gate current waveform, thereby reducing switching loss and element stress while maintaining simple structure and high reliability.
2Loss of energy
If active control circuits are added to reduce switching loss and element stress, then switching efficiency improves, but the number of components increases and device complexity increases
Solution Approach 1:
The patent merges multiple functions into a single gate driver circuit. The current-type gate driver integrates the gate signal generation, current limiting, and switching control functions into one unified circuit structure. This consolidation achieves active control to reduce switching loss while avoiding the need for separate complex control circuits, mirror circuits, and multiple current sources that would increase component count.
Solution Approach 2:
The gate driver circuit is designed with multi-functionality to handle both turn-on and turn-off operations, as well as providing current limiting and active control, all within a single universal circuit structure. This eliminates the need for separate dedicated circuits for each function, thereby reducing the overall number of components while maintaining the ability to reduce switching loss and element stress.
3Power
If the rated voltage and current capacity of switching elements is increased to handle higher operating conditions, then power capacity increases, but switching loss increases and element stress increases
Solution Approach 1:
The patent changes the gate driving parameter from voltage-based to current-based control. By controlling the gate current waveform characteristics, the circuit can optimize the switching process for high-power applications. This enables high power capacity switching elements to operate with reduced switching loss, as the current-type driver can precisely control the gate current to minimize overlap between voltage and current during switching transitions.
Data Source
AI summary
A power converting apparatus and a vehicle including the same according to an embodiment of the present disclosure includes a switching element; and a gate drive unit configured to apply a gate driving signal for driving the switching element to a gate terminal of the switching element, wherein the gate drive unit includes: a current source unit including a source current for sourcing current to the gate terminal in a turn-on section of the switching element, and a sink current for sinking current from the gate terminal in a turn-off section of the switching element; a control current for sinking the current from the gate terminal during a partial section of the turn-on section and the turn-off section of the switching element; and a control current controller configured to control an operation of the control current.