Pre-Charge Energy Conversion Circuit for Safe AC/DC Power Transfer
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Solution Overview
Problem
Existing electrical devices lack efficient mechanisms for bidirectional energy transfer between energy sources and sinks, particularly in scenarios involving AC and DC inputs, leading to inefficiencies and potential power loss during connection establishment.
Innovation Solution
A system with two user-accessible ports for AC and DC inputs, utilizing a diode bridge and blocking diodes to prevent backfeeding, along with a pre-charge circuit and controller to manage energy transfer, ensuring safe and efficient connection with energy sources like batteries and grids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a connection is established between energy conversion device and energy source, then energy transfer can occur, but power loss and potential backfeeding occur during connection establishment
Solution Approach 1:
The pre-charge circuit charges the capacitor to the operating voltage of the energy conversion device before the switchable connection is closed. This preliminary action ensures that when the connection is established, there is no voltage difference to cause inrush current or power loss, while also preventing backfeeding by ensuring the device voltage matches or exceeds the energy source voltage before connection
2Productivity
If bidirectional energy transfer is enabled between AC and DC inputs, then energy exchange efficiency improves, but risk of backfeeding increases
Solution Approach 1:
Blocking diodes are introduced as intermediary components between the AC and DC inputs and the energy conversion device. These diodes allow current to flow in only one direction, enabling efficient energy transfer from either input type while preventing backfeeding into the input sources, thus resolving the contradiction between bidirectional energy transfer capability and backfeeding prevention
3Loss of energy
If pre-charge circuit charges capacitor to operating voltage before connection, then power loss is minimized, but device complexity increases
Solution Approach 1:
The pre-charge circuit is merged with the main energy transfer circuit, sharing common components such as the capacitor and switchable connection. The blocking diodes serve dual purposes: enabling bidirectional energy transfer and preventing backfeeding. This integration reduces overall circuit complexity while maintaining the pre-charge function to minimize power loss during connection establishment
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 safe and efficient bidirectional energy transfer, minimizing power loss and ensuring stable connection establishment, allowing for seamless energy exchange between various energy sources and sinks.
Implementation Method 1
The user accessible AC input can be used to generate the DC bus voltage using a diode bridge
Implementation Method 2
Blocking Diodes provide an OR connection for the two inputs and prevent back feeding of power from the external AC source
Implementation Method 3
The pre-charge circuit can charge a capacitor to an operating voltage. The pre-charge circuit can charge the capacitor associated with the one or more power delivery interfaces with the energy from the user accessible interface
Implementation Method 4
high voltage (HV) to LV isolated switch-mode power supply (SMPS)
Data Source
AI summary
Energy conversion is provided. An energy conversion device can include one or more power delivery interfaces. The energy conversion device can include a pre-charge circuit configured to charge a capacitor to an operating voltage. The energy conversion device can include a user accessible interface configured to provide energy to the pre-charge circuit. The pre-charge circuit can charge the capacitor associated with the one or more power delivery interfaces. The user-accessible interfaces can include a direct current (DC) input. The user-accessible interfaces can include an alternating current (AC) input.