AC Voltage Detection Device Using Optical Pulse Transmission
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Solution Overview
Problem
Existing AC voltage detection methods, particularly those using zener diodes and photocouplers, are limited in their ability to accurately detect AC voltage on the secondary side, necessitating the development of new methods for effective AC voltage detection.
Innovation Solution
An AC voltage detection device comprising a rectifying circuit, a voltage-pulse conversion circuit that converts the rectified voltage to a first pulse signal with a period shorter than half the AC voltage period, and a pulse transmission circuit that converts the signal to a physical signal and back to an electrical signal, allowing the controller to calculate the AC voltage value from characteristic values of the second pulse signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the AC voltage is detected using conventional methods (zener diode, photocoupler) on the primary side, then the detection structure is simple, but the detection of AC voltage on the secondary side is not achievable
Solution Approach 1:
The patent introduces a pulse transmission circuit as an intermediary component that converts electrical signals to optical signals and back, enabling AC voltage detection on the secondary side while maintaining electrical isolation. This mediator allows information transfer across the isolation barrier without direct electrical connection.
Solution Approach 2:
The patent replaces the conventional direct electrical detection method with an optical signal transmission method. By using light as the transmission medium instead of electrical signals, the system achieves secondary side detection capability while maintaining electrical isolation between primary and secondary sides.
2Measurement precision
If the period of the first pulse signal is made shorter than half the AC voltage period, then the AC voltage detection accuracy is improved, but the control unit processing load increases
Solution Approach 1:
The patent divides the detection function into separate modules: the pulse transmission circuit handles signal conversion and transmission, while the control unit only needs to count pulses and calculate RMS voltage. This segmentation reduces the processing burden on the control unit while maintaining high detection accuracy through the shorter period pulse signal.
Solution Approach 2:
The pulse transmission circuit automatically generates the first pulse signal with period shorter than half the AC voltage period, and the control unit simply counts these pulses to calculate the RMS voltage. The system performs self-service detection where the circuit structure itself enables accurate measurement without requiring complex control unit processing.
3Measurement precision
If a pulse transmission circuit with electrical insulation is used, then the AC voltage can be detected on the secondary side, but the device complexity increases
Solution Approach 1:
The pulse transmission circuit serves as an intermediary that provides electrical isolation while enabling signal transmission. By using optical signals as the medium, the circuit achieves galvanic isolation between primary and secondary sides, allowing safe and accurate voltage detection on the secondary side.
Solution Approach 2:
The pulse transmission circuit performs multiple functions: it provides electrical isolation, converts electrical signals to optical signals and back, and enables AC voltage detection on the secondary side. This multi-functional component reduces overall system complexity despite the added isolation requirement.
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
Enables accurate detection of AC voltage on the secondary side by converting the rectified voltage to a first pulse signal with a shorter period, reducing the load on the control unit and providing a new method for AC voltage detection.
Implementation Method 1
a rectifying circuit configured to rectify an AC voltage output from an AC power source
Implementation Method 2
a voltage-pulse conversion circuit configured to convert a rectified voltage rectified in the rectifying circuit to a first pulse signal having a period shorter than a half of a period of the AC voltage
Implementation Method 3
a pulse transmission circuit configured to perform signal transmission with electrical insulation by converting the first pulse signal to a physical signal other than an electrical signal and converting the physical signal to a second pulse signal being an electrical signal
Implementation Method 4
a controller to which the second pulse signal is input, wherein the controller is configured to calculate a voltage value of the AC voltage from a characteristic value of the second pulse signal
Data Source
AI summary
An AC voltage detection device has a rectifying circuit configured to rectify an AC voltage output from an AC power source, a voltage-pulse conversion circuit configured to convert a rectified voltage rectified in the rectifying circuit to a first pulse signal having a period shorter than a half of a period of the AC voltage, a pulse transmission circuit configured to perform signal transmission with electrical insulation by converting the first pulse signal to a physical signal other than an electrical signal and converting the physical signal to a second pulse signal being an electrical signal, and a controller to which the second pulse signal is input. The controller calculates the voltage value of the AC voltage from a characteristic value of the second pulse signal.