Power Supply Input Current Estimation via Voltage and Frequency Detection
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Solution Overview
Problem
Existing methods for obtaining input current of power supplies are either costly due to the need for additional components like optical couplers and current transformers or inaccurate, as they can only estimate real power rather than input current, and the precision of X-capacitor capacitance affects the accuracy of input current measurement.
Innovation Solution
A method that couples the power supply to an AC power source, detects voltage and frequency, and estimates electric power information, including input current and capacitance, using equations and threshold comparisons to update calculations dynamically, without requiring additional costly components like optical couplers or current rectifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a power monitoring chip is provided between the power supply and input terminal, then the input current can be obtained, but the manufacturing cost increases due to additional optical coupler and isolated auxiliary power source
Solution Approach 1:
The patent extracts the current measurement function from the traditional power monitoring chip approach and implements it through estimation based on voltage and frequency detection. By removing the need for optical couplers and isolated auxiliary power sources, the solution achieves current measurement capability while significantly reducing device complexity and manufacturing cost.
Solution Approach 2:
The patent replaces the physical electrical measurement system (power monitoring chip, optical coupler, current transformer) with a computational estimation system. By using voltage and frequency detection combined with mathematical estimation algorithms, the solution substitutes complex electrical measurement hardware with a simpler computational approach that achieves comparable measurement precision.
2Device complexity
If digital signal processor or single chip of PFC circuit is used to estimate input current, then the manufacturing cost is reduced, but the measurement precision deteriorates because only real power can be estimated instead of input current
Solution Approach 1:
The patent changes the estimation parameters from direct current measurement to voltage and frequency-based estimation. By detecting voltage and frequency parameters and using them to estimate the input current through mathematical relationships, the solution achieves accurate current estimation without requiring direct current sensing hardware, thus maintaining low device complexity while improving measurement precision.
3Device complexity
If the capacitance of X-capacitor is not precisely known, then the manufacturing cost is reduced, but the measurement precision of input current deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the system detects voltage and frequency parameters, estimates the input current, and uses this information to dynamically adjust and refine the capacitance value of the X-capacitor. This feedback loop allows the system to compensate for capacitance variations and maintain high measurement precision even when the initial capacitance specification has tolerances, without requiring additional costly components.
Data Source
AI summary
A method for obtaining electric power information is applied with a power supply and includes following steps of coupling the power supply to an AC power source; detecting a voltage of the AC power source to obtain a first voltage; detecting a frequency of the AC power source to obtain a first frequency; and estimating an electric power information of the power supply in accordance with the first voltage and the first frequency. The electric power information includes an input current, an input voltage or an input power outputted from the AC power source to the power supply.