Resonant Power Converter Primary-Side Overcurrent Protection
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Solution Overview
Problem
Resonant power converters face inefficiencies due to the delay in sensing overcurrent conditions, leading to potential component over-design to handle overcurrents, which increases cost, size, and weight.
Innovation Solution
Implementing a primary-side controller that senses current in the primary winding and limits the AC signal frequency during overcurrent conditions, thereby reducing current flow before shutdown, allowing components to be designed for nominal power conditions rather than overcurrent scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional overcurrent protection is implemented with finite sensing cycles, then the power converter can detect overload conditions, but substantial overcurrent conditions occur before shutdown, requiring over-design of components which increases cost, size, and weight
Solution Approach 1:
The patent applies preliminary action by detecting overcurrent conditions at the very beginning of the AC signal cycle and immediately limiting current during the off-time, before substantial overcurrent can occur. This is achieved by sensing current during the off-time of the electrically-controlled switches and comparing it against a threshold, then adjusting the duty cycle or frequency in real-time to prevent overcurrent, rather than waiting for a finite number of cycles to accumulate data before taking protective action.
2Reliability
If traditional overcurrent protection is implemented with finite sensing cycles, then the power converter can detect overload conditions, but substantial overcurrent conditions occur before shutdown, requiring over-design of components which increases cost and size
Solution Approach 1:
The patent applies preliminary action by detecting overcurrent conditions at the very beginning of the AC signal cycle and immediately limiting current during the off-time, before substantial overcurrent can occur. This is achieved by sensing current during the off-time of the electrically-controlled switches and comparing it against a threshold, then adjusting the duty cycle or frequency in real-time to prevent overcurrent, rather than waiting for a finite number of cycles to accumulate data before taking protective action.
3Reliability
If traditional overcurrent protection is implemented with finite sensing cycles, then the power converter can detect overload conditions, but substantial overcurrent conditions occur before shutdown, requiring over-design of components which increases cost
Solution Approach 1:
The patent applies preliminary action by detecting overcurrent conditions at the very beginning of the AC signal cycle and immediately limiting current during the off-time, before substantial overcurrent can occur. This is achieved by sensing current during the off-time of the electrically-controlled switches and comparing it against a threshold, then adjusting the duty cycle or frequency in real-time to prevent overcurrent, rather than waiting for a finite number of cycles to accumulate data before taking protective action.
Solution Approach 2:
The patent implements feedback by continuously monitoring the current during the off-time of the switches and using this information to adjust the duty cycle or frequency of the AC signal. The controller compares the sensed current against a predetermined threshold and modifies the switching parameters accordingly, creating a closed-loop control system that actively prevents overcurrent conditions rather than merely detecting and responding to them after the fact.
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 limits current during overloads and short circuits, reducing the need for over-designing components, thus optimizing the size, cost, and efficiency of resonant power converters.
Implementation Method 1
Resonant power converters utilize a resonant circuit on the primary side of the power converter to create an alternating current (AC) signal
Data Source
AI summary
Resonant power converters. Example embodiments are integrated circuit controllers for a resonant power converter, the controllers including: a frequency controller configured to control frequency of signals driven to a high-side gate terminal and a low-side gate terminal; a fault detector configured to sense an overcurrent condition of a primary winding of the resonant power converter, and to assert an overcurrent signal responsive to the overcurrent condition; a feedback controller that, during periods of time when the overcurrent signal is de-asserted, is configured to sense a signal representative of output voltage by way of the feedback terminal and to create an intermediate signal; and the feedback controller further configured to, during periods when the overcurrent signal is asserted, modify the intermediate signal to increase the frequency of the signals driven to the high-side gate terminal and the low-side gate terminal.