Inverter Pre-Charging Circuit Segmentation for PCB Design Freedom
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Solution Overview
Problem
The existing pre-charging circuit in inverters limits PCB design flexibility due to a single current path, which can cause design obstacles and is not effectively protected against over-currents during normal operation.
Innovation Solution
A pre-charging circuit configuration that includes a relay between the output node of the rectifier and the input node of the DC-link capacitor, and a pre-charging resistor between the output node of the rectifier and the input node of the DC/AC converter unit, establishing an additional current path during pre-charging and normal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single current path is used in the pre-charging circuit, then the circuit structure is simple, but the PCB design freedom is limited and over-current protection is insufficient
Solution Approach 1:
The pre-charging circuit is segmented into two separate current paths: one path through the pre-charging resistor and another through the relay. This segmentation allows independent routing on the PCB, providing design freedom while maintaining circuit functionality. Each path can be optimized separately for layout and protection requirements.
Solution Approach 2:
The relay acts as an intermediary component that enables alternative current flow paths. During normal operation, the relay provides a low-impedance path that bypasses the pre-charging resistor, while during pre-charging, the relay is open and current flows through the resistor. This intermediary mechanism enables flexible PCB routing without compromising protection functionality.
2Ease of manufacture
If the pre-charging resistor is connected between nodes P2 and DCP, then the circuit follows conventional design, but the current path is constrained and PCB layout flexibility is reduced
Solution Approach 1:
The circuit transitions from a static single-path design to a dynamic multi-path design where the relay state determines the active current path. During pre-charging, the relay is open and current flows through the pre-charging resistor; during normal operation, the relay closes to provide an alternative path. This dynamic switching enables flexible PCB layout while maintaining reliable over-current protection through the shunt resistor monitoring capability.
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 configuration provides design freedom for PCB layout by creating a distinct current path from conventional designs, effectively managing over-currents and enhancing protection mechanisms.
Implementation Method 1
a relay disposed between an output node of the rectifier and an input node of the DC-link capacitor
Implementation Method 2
A pre-charging resistor (221) of the pre-charging circuit (220) is operated only when an initial power of the inverter (200) is inputted, and prevents an unnecessary power loss of charging resistor by diverting a current flow to a relay (222) in a normal state
Implementation Method 3
an inverter is a power converting device configured to convert an inputted AC electric power to DC electric power having a predetermined frequency and voltage
Implementation Method 4
stores the power in a DC-link capacitor (230)
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A pre-charging circuit of inverter is disclosed, the pre-charging circuit of inverter including a relay arranged between an output node of the rectifier and an input node of the DC-link capacitor, and a pre-charging resistor arranged between an output node of the rectifier and an input node of the inverter unit, whereby a degree of freedom for PCB design can be obtained.