Converter Cell Powering Gate Units via Clamp Inductor
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Solution Overview
Problem
Designing a very low gain DC-DC converter with high power requirements for powering gate units in high voltage power conversion systems is challenging due to significant power consumption by gate units and limitations in peak current through switching elements.
Innovation Solution
A converter cell utilizing a clamp inductor to power gate units and additional electronics, with a first energy converter providing power from the clamp inductor during normal operation, and a second energy converter, such as a bidirectional DC-DC converter, used to supplement power when the clamp inductor energy is insufficient, allowing for efficient energy utilization and charging of storage elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a very low gain DC-DC converter is used to power gate units, then the voltage transformation from kilo-volts to suitable gate unit voltage is achieved, but the converter becomes challenging to design due to high power requirements and limiting peak current through switching elements
Solution Approach 1:
The power delivery function is segmented between two sources: the clamp inductor handles high-power transient demands during normal operation, while the energy storage element (capacitor) supplemented by a second DC-DC converter handles low-current operation. This segmentation allows each component to be optimized for its specific operating regime, avoiding the need for a single complex very low gain DC-DC converter to handle all conditions.
Solution Approach 2:
The clamp inductor, which already exists in the converter cell for its primary function of restricting rate of change of current, is made to serve an additional function by providing power to the gate units. This self-service approach eliminates the need for dedicated high-power conversion circuitry, as the existing inductor energy is directly utilized to power the gate units during normal operation.
2Device complexity
If the clamp inductor is used to power gate units during normal operation, then the need for a very low gain DC-DC converter is eliminated, but the clamp inductor energy may be insufficient when average current through the converter cell is very low
Solution Approach 1:
An energy storage element (capacitor) is pre-charged and held ready to supplement power from the clamp inductor when needed. During normal operation with sufficient current, the clamp inductor alone powers the gate units. When current drops below a threshold, the pre-charged capacitor automatically supplements the power, ensuring continuous adequate power delivery without requiring complex real-time conversion circuitry.
Solution Approach 2:
The system dynamically changes its power configuration based on operating parameters (average current level). During high-current operation, only the clamp inductor supplies gate unit power. During low-current operation, the system transitions to using both the clamp inductor and the energy storage element, effectively changing the power delivery parameters to match the reduced available energy from the inductor.
3Loss of energy
If a bidirectional DC-DC converter is added to enable energy storage and charging, then energy utilization efficiency is improved, but the device complexity increases
Solution Approach 1:
The second DC-DC converter is designed with bidirectional capability, allowing it to perform multiple functions: charging the energy storage element from the clamp inductor during high-current operation, and discharging to supplement gate unit power during low-current operation. This multi-functionality maximizes energy utilization efficiency by enabling energy recovery and reuse, while the single bidirectional converter component adds less complexity than would be required with separate unidirectional converters for each function.
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 reduces the need for a low gain DC-DC converter, efficiently powers gate units and cell electronics across varying current conditions, and enables energy storage and reuse, thereby optimizing power management in high voltage applications.
Implementation Method 1
a clamp inductor provided to restrict a rate of change of current from the energy storage element to the switching elements; and a first energy converter provided in parallel to the clamp inductor, the first energy converter being provided to power the gate units by utilising energy from the clamp inductor
Implementation Method 2
an energy storage element; a second energy converter, such as a bidirectional DC-DC converter, used to supplement power when the clamp inductor energy is insufficient
Data Source
AI summary
A converter cell includes a first terminal; a second terminal; a plurality of switching elements provided with respective gate units; an energy storage element; an clamp inductor provided to restrict a rate of change of current from the energy storage element to the switching elements; and a first energy converter provided in parallel to the clamp inductor. The first energy converter is provided to power the gate units by utilising energy from the clamp inductor when the converter cell changes state to be in a short circuit state.