Power Controller Open-Circuit Protection via Winding Voltage Deviation
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Solution Overview
Problem
Power controllers using primary-side regulation (PSR) fail to accurately regulate output voltage during open-circuit conditions in the auxiliary winding, leading to potential over-voltage damage due to deformation of winding voltage waveforms, as they provide incorrect feedback information.
Innovation Solution
A power controller with a PWM signal generator and deviation detector that monitors the winding voltage and asserts an open protection signal to stop power conversion when predetermined voltage deviations are detected, preventing over-voltage by keeping the power switch turned OFF constantly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If primary-side regulation (PSR) is used to monitor and regulate output voltage by detecting winding voltage at the auxiliary winding, then output voltage regulation is achieved, but open-circuit protection is insufficient when the auxiliary winding is disconnected
Solution Approach 1:
The patent applies preliminary action by detecting voltage deviations at the auxiliary winding before they can cause over-voltage damage. The controller monitors the winding voltage during each switching cycle and compares it against expected values, enabling early detection of open-circuit conditions before they propagate to the output stage and cause harm.
Solution Approach 2:
The patent implements feedback by continuously monitoring the auxiliary winding voltage and using this information to regulate output voltage while simultaneously detecting abnormal conditions. The detected winding voltage is fed back to the controller, which adjusts the power conversion accordingly and triggers protection mechanisms when deviations indicate an open-circuit fault.
2Adaptability or versatility
If the auxiliary winding ground end is disconnected from input ground, then open-circuit test condition is created, but winding voltage waveform deforms causing wrong regulation information
Solution Approach 1:
The patent applies preliminary anti-action by implementing a protection mechanism that counteracts the harmful effects of waveform deformation caused by open-circuit conditions. The controller detects the abnormal waveform characteristics and actively prevents them from causing incorrect regulation decisions by triggering a protection state that overrides normal regulation based on the degraded feedback information.
3Productivity
If winding voltage waveform deformation occurs due to open-circuit, then wrong feedback information is provided to control loop, but output voltage regulation continues without protection
Solution Approach 1:
The patent converts the harmful waveform deformation into a beneficial protection signal. By monitoring for specific voltage deviation patterns, the system uses the abnormal waveform characteristics as an indicator to trigger protection mechanisms. The harmful deformation is thus transformed into useful information that activates the open-circuit protection, preventing over-voltage damage while allowing continuous operation under normal conditions.
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
Effectively provides open-circuit protection by preventing output voltage from rising further, thus safeguarding the electric load from potential damage during open-circuit conditions.
Implementation Method 1
a transformer TF having a primary winding PRM, a secondary winding SEC and an auxiliary winding AUX, each inductively coupled to another
Implementation Method 2
Power controller 14 provides driving signal SDRV from driving node DRV to turn ON and OFF power switch SW, so as to alter the voltage across primary winding PRM
Data Source
AI summary
A power controller provides open-circuit protection for a power supply when an open circuit occurs between a ground end of an auxiliary winding and an input ground. The power controller provides a PWM signal to determine an ON time and an OFF time of a power switch connected in series between an input voltage and the input ground. A deviation detector in the power controller detects a winding voltage at a floating end of the auxiliary winding during the ON time, and asserts an open protection signal when a variation of the winding voltage during the ON time fits a first predetermined condition, so as to keep the power switch turned OFF and provide the open-circuit protection.