Power Line Communication Modulation Using Precharged Capacitor
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Solution Overview
Problem
The existing power line communication technology using an H-bridge circuit for driving power lines results in high power loss due to the requirement for low on-resistance switch elements, leading to increased component costs, especially when a large current load is connected.
Innovation Solution
A power line communication device that modulates the supply voltage using a modulation capacitor precharged with the modulation amplitude voltage, an inductor connected between the power source and the power line, and a switch unit that determines the polarity of the modulation capacitor connected to the power line according to the transmission data, allowing for reduced loss and lower component costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If an H-bridge circuit is used to drive power lines in power line communication, then voltage signals can be transmitted by switching polarity, but power loss increases due to the requirement for low on-resistance switch elements
Solution Approach 1:
The patent extracts the modulation function from the power transmission path by using a separate modulation capacitor that is precharged to a specific voltage. This capacitor is connected to the power line through a switch, allowing voltage modulation without requiring the main power switches to have low on-resistance. The modulation function is separated from the power switching function, enabling the use of higher on-resistance switches in the H-bridge circuit.
Solution Approach 2:
The modulation capacitor is precharged to a predetermined voltage level before being connected to the power line. This preliminary charging action allows the capacitor to immediately impart the desired voltage modulation when switched onto the power line, eliminating the need for continuous high-current switching through the H-bridge circuit and reducing power loss in the switches.
2Loss of energy
If low on-resistance switch elements are used in the H-bridge circuit, then power loss is reduced, but component cost increases
Solution Approach 1:
The patent uses a modulation capacitor that can be charged to a specific voltage and then switched onto the power line for brief modulation cycles. This approach allows the use of standard, lower-cost switch elements in the H-bridge circuit rather than requiring expensive low on-resistance switches, as the modulation is achieved through the precharged capacitor rather than continuous high-current switching.
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
This solution reduces power loss and component costs by using a modulation capacitor and inductor to modulate the supply voltage, enabling the use of switching elements with relatively high on-resistance, thus effectively suppressing the cost of parts while maintaining efficient communication.
Implementation Method 1
a modulation capacitor precharged with a modulation amplitude voltage
Implementation Method 2
an inductor connected between the power source and the power line
Data Source
AI summary
A power line communication device includes a DC power source device, a power line, and a master station that modulates a supply voltage VBUS supplied to the power line according to transmission data to be transmitted. The master station includes a modulation capacitor that is precharged with a modulation amplitude voltage, a polarity switch unit that determines a polarity of the modulation capacitor connected to the power line according to transmission data, and an inductor connected between the DC power source device and the power line.