Power Conversion Device Diode Isolation Switching Noise
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Solution Overview
Problem
In air conditioners, the mounting of multiple switching elements on a single substrate leads to switching noise due to ON/OFF control, causing malfunction as noise propagates through power supply lines when switching element control circuits share the same power supply.
Innovation Solution
A power conversion device is designed with a constant voltage output circuit, diode elements connected in the forward direction in power supply lines, and capacitors between diode elements and switching element control circuits, which reduces switching noise by blocking its propagation through the power supply lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple switching elements are mounted on the same substrate to improve power conversion efficiency, then productivity and power conversion capability are improved, but switching noise is generated and propagated through power supply lines causing malfunctions
Solution Approach 1:
The power supply system is segmented into multiple independent power supply lines, each dedicated to specific switching element control circuits. This segmentation prevents noise propagation between different control circuits while maintaining efficient power distribution to multiple switching elements mounted on the substrate.
Solution Approach 2:
Diode elements are introduced as intermediary components in the power supply lines. These diodes act as one-way valves for current flow, blocking reverse current that could carry switching noise from one control circuit to another, thereby isolating noise while allowing power delivery.
2Device complexity
If switching element control circuits share the same power supply to reduce device complexity, then device complexity is reduced, but noise mutually propagates through power supply lines causing malfunctions
Solution Approach 1:
The shared power supply is divided into multiple separate power supply lines, each serving specific control circuits. This segmentation maintains the simplicity of having a single power source while preventing noise coupling between circuits through the use of dedicated lines and diode isolation.
Solution Approach 2:
Diode elements are placed in each power supply line as intermediary components that allow forward current flow from the power source to control circuits but block reverse current flow that would carry noise between circuits. This maintains reliability without significantly increasing device complexity.
3Reliability
If diode elements are connected in power supply lines to block noise propagation, then reliability is improved by reducing switching noise, but device complexity increases due to additional components
Solution Approach 1:
Diode elements are used as intermediary components that provide noise isolation with minimal circuit complexity. Each diode is simply inserted in series in the power supply line, requiring no complex control logic or additional circuitry beyond the diode itself.
Solution Approach 2:
The diode elements automatically perform noise blocking based on their inherent electrical characteristics without requiring external control or additional components. The diode's forward voltage drop and unidirectional conduction properties provide the isolation function inherently.
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
The solution effectively reduces malfunctions caused by switching noise, enhances detection performance of voltage and current in active filter control circuits, and improves harmonic suppression performance.
Implementation Method 1
a diode element that is connected in a forward direction from the constant voltage output circuit to the switching element control circuit in the power supply lines
Implementation Method 2
a capacitor having one end connected between the diode elements and the switching element control circuits in the power supply lines and the other end connected to a ground
Data Source
AI summary
A power conversion device including a constant voltage output circuit 20 that outputs a constant voltage; an active filter control circuit 21 and the like that are operated based on the constant voltage applied from the constant voltage output circuit 20 through power supply lines V and control switching elements 122, 130, and 210 for performing power conversion; diode elements D0 to D3 that are connected in a forward direction from the constant voltage output circuit 20 to the active filter control circuit 21 and the like in the power supply lines V; and capacitors C0 to C4 having one end connected between the diode elements and the active filter control circuit 21 and the like in the power supply lines V and the other end connected to a ground.