PFC Current Sampling Timing Compensation for Turn-On Delay
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Solution Overview
Problem
In PFC circuits, the delay in the turn-on signal passing through switching components leads to an error in the sampled current due to the delayed turn-on of the switching component, causing the actual sampled current to be smaller than the theoretical sampled current.
Innovation Solution
A current sampling method that adjusts the theoretical sampling time point based on a compensation duration to ensure consistency between the theoretical and actual sampling time points, using methods such as acquiring the first and second durations of the turn-on signal and inductor component charging to determine the target sampling time point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the turn-on signal is passed through the switching component, then the switching component can be turned on to control the PFC circuit, but the internal resistance of the switching component causes a delay in the turn-on signal, resulting in a delay in the turn-on of the switching component and causing the actual sampled current to be smaller than the theoretical sampled current
Solution Approach 1:
The patent applies preliminary action by measuring the actual turn-on duration of the switching component and using this measurement to calculate a compensation duration before performing current sampling. The control device adjusts the sampling timing in advance based on the measured delay, ensuring that the sampling occurs at the correct moment despite the inherent delay in the switching component's turn-on process. This resolves the contradiction by preparing the sampling timing beforehand based on actual component behavior.
Solution Approach 2:
The patent implements feedback by measuring the actual turn-on duration of the switching component and using this feedback information to adjust the current sampling timing. The control device continuously monitors the switching component's behavior and adjusts the sampling strategy based on the measured delay, creating a closed-loop system that compensates for the delay and ensures accurate current sampling despite the switching component's internal resistance effects.
2Device complexity
If the theoretical sampling time point is used for current sampling, then the sampling process is simple, but the actual sampled current does not match the expected sampled current due to the delay in the turn-on signal
Solution Approach 1:
The patent applies self-service by having the control device automatically measure the turn-on duration of the switching component and autonomously calculate and adjust the sampling timing without requiring external intervention. The system uses its own internal resources to monitor the switching component's behavior and self-correct the sampling timing, maintaining simplicity while improving accuracy through automated feedback and adjustment mechanisms.
Data Source
AI summary
A current sampling method and apparatus for a PFC circuit, an air conditioner, and a computer-readable storage medium are provided. The method includes: outputting a turn-on signal to a switching device; acquiring a first duration of the turn-on signal, and according to the first duration, determining a theoretical sampling time point for sampling a PFC circuit; according to the theoretical sampling time point, acquiring a second duration within which the switching device is turned on; according to the first duration and the second duration, determining a compensation duration for performing current sampling on the PFC circuit; and adjusting the theoretical sampling time point according to the compensation duration to obtain a target sampling time point, and performing current sampling on the PFC circuit according to the target sampling time point.