Devices, systems, and methods for reducing leakage current in power converters
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Solution Overview
Problem
Existing HVAC systems face issues with leakage current in power converters, which can cause nuisance trips in ground fault circuit interrupters (GFCIs), leading to sub-optimal comfort performance.
Innovation Solution
The implementation of a power converter system that includes a rectifier, a DC-to-DC converter, a multi-pole common mode filter, and an inverter, which filters and reduces common mode noise by removing high-frequency components, thereby maintaining leakage current below the trip threshold of a GFCI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a power converter is used in HVAC systems, then power conversion and motor control are achieved, but leakage current increases causing GFCI nuisance trips
Solution Approach 1:
The patent segments the common mode filter into multiple poles (first pole, second pole, third pole) with distinct functions. The first pole filters common mode noise from rectifier output, the second pole filters noise from DC-DC converter, and the third pole provides additional filtering. This segmentation allows comprehensive noise reduction at different stages without excessive leakage current to GFCI devices.
Solution Approach 2:
The patent introduces a multi-pole common mode filter as an intermediary component between the power converter stages and the GFCI-protected circuit. This filter acts as a mediator that blocks high-frequency common mode noise and leakage current paths while allowing legitimate power conversion operations to proceed, preventing GFCI nuisance trips.
2Object-affected harmful factors
If common mode noise filtering is increased to reduce leakage current, then GFCI compatibility improves, but device complexity increases
Solution Approach 1:
The common mode filter is divided into three distinct poles, each handling specific noise sources at different stages of power conversion. This segmentation distributes the filtering function across multiple simpler modules rather than requiring one complex filter, making the overall system more manageable and maintainable while achieving comprehensive noise reduction.
Solution Approach 2:
The first pole of the common mode filter performs preliminary filtering of common mode noise from the rectifier output before the noise can propagate through subsequent stages. This preliminary action reduces the burden on later filtering stages and prevents excessive leakage current generation, achieving effective noise reduction with moderate complexity.
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 effectively reduces leakage current in HVAC systems, preventing GFCI trips and ensuring reliable operation of HVAC systems even when connected to GFCI-protected circuits.
Implementation Method 1
a multi-pole common mode filter for removing a high frequency component from common mode noise in the DC power with the second voltage to produce a filtered DC power
Data Source
AI summary
Devices, systems, and methods are disclosed for reducing leakage current in power converters, such as for HVAC systems, to facilitate compatibility with GFCI devices. In various embodiments, the power converter may include components to filter and/or reduce common mode noise, such as by removing high frequency components of the common mode noise, while maintaining leakage current below a trip threshold of a GFCI device.