Electricity Meter Hold-Up Circuit for AC Outage Last-Gasp Power
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Solution Overview
Problem
Existing electricity meters struggle to efficiently communicate with utility providers during AC power outages due to the need for large and expensive storage capacitors to maintain radio operation, which can deplete energy quickly.
Innovation Solution
An AC line voltage detection circuit is implemented, comprising an AC sense circuit, a power supply control circuit, and a power supply hold-up circuit, to manage power supply operations during outages, ensuring efficient energy conservation for last-gasp communications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the secondary power supply operates in voltage recovery mode during AC power loss, then the battery discharge current increases to maintain voltage, but the battery life is reduced due to excessive current draw
Solution Approach 1:
The patent applies dynamics by transitioning the secondary power supply between two operational modes based on real-time conditions: voltage recovery mode (when USB power is present) and power supply mode (when AC power is lost). This dynamic switching optimizes battery current draw by using USB power to recharge the battery during voltage recovery, thereby extending battery life while maintaining voltage output when needed.
2Duration of action of stationary object
If the secondary power supply switches between voltage recovery mode and power supply mode, then the battery life is extended, but the control complexity increases
Solution Approach 1:
The patent implements feedback control by continuously monitoring the operational state of the power supply system (AC power availability, USB power availability, battery charge level) and automatically switching between voltage recovery mode and power supply mode. This feedback mechanism manages the complexity by using simple state-based decision logic rather than complex algorithms, extending battery life through automated mode transitions.
3Volume of moving object
If the electricity meter uses a small capacity battery to minimize size and cost, then the device dimensions are reduced, but the battery cannot sustain the meter operation during extended AC power loss
Solution Approach 1:
The patent ensures continuity of useful action by using USB power to continuously recharge the battery during voltage recovery mode, maintaining the battery charge level. This allows a small-capacity battery to sustain the electricity meter operation during extended AC power loss periods, as the battery is repeatedly recharged from USB power rather than relying on a large initial capacity.
Data Source
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AI summary
An AC line voltage detection circuit includes an AC sense circuit, a power supply control circuit, and a power supply hold-up circuit. The AC sense circuit is configured to generate a signal to a processor and to the power supply control circuit in response to sensing an absence of AC line voltage. The power supply control circuit is configured to generate a control signal to a power supply that provides power to the processor to shut down the power supply. The processor is configured generate a signal to the power supply hold-up circuit configured to generate a signal to the power supply control circuit to prevent shut down of the power supply. The power supply hold-up circuit signal overrides the AC sense circuit signal. The processor is further configured to generate a subsequent signal to the power supply hold-up circuit to permit shut down of the power supply.