Common-Core Inverter Modules for Ripple Current Reduction
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Solution Overview
Problem
Inverters face challenges with ripple currents causing conduction losses and potential damage due to higher root mean square current, necessitating larger conductors and posing regulatory concerns regarding safety hazards.
Innovation Solution
The inverter design incorporates a magnetic core with bifilar windings and multiple isolation stages, where primary and secondary windings are wound around common legs to share ripple currents, reducing high-frequency magnetic flux and electrical currents through appropriate switching algorithms and geometric patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If windings are connected in parallel around a common core, then conduction losses are reduced, but ripple currents increase
Solution Approach 1:
The inverter is divided into multiple independent inversion modules, each with its own winding connected to the common core. This segmentation allows each module to handle a portion of the total power, reducing the current through each individual winding and thereby reducing conduction losses while distributing the ripple current effects across multiple modules
Solution Approach 2:
Multiple windings are connected in parallel around a common magnetic core, merging their magnetic effects to reduce ripple currents. The combined magnetic flux from multiple windings cancels out ripple components, while the parallel connection allows current sharing that reduces conduction losses in each individual winding
2Reliability
If larger conductors are used to handle ripple currents, then reliability improves, but device complexity and cost increase
Solution Approach 1:
The total current handling is segmented across multiple inversion modules with parallel windings. Each module uses smaller conductors that can handle reduced current, avoiding the need for single large conductors while maintaining system reliability through modular redundancy and distributed current handling
Solution Approach 2:
A common magnetic core serves as an intermediary that couples multiple windings together. This core enables magnetic flux sharing and ripple current cancellation between modules, allowing smaller conductors to achieve the same effective current handling capability that would otherwise require larger conductors in a single-module design
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 effectively reduces ripple currents, minimizing conduction losses and preventing damage to inverter components, while adhering to regulatory standards by stabilizing voltage and reducing the risk of hazards.
Implementation Method 1
A power inverter, or inverter, is a power electronic device or circuitry that changes direct current (DC) to alternating current (AC)
Implementation Method 2
Windings around a common core of the inverter may cause ripple currents, in the DC input, to be shared by the inversion modules
Data Source
AI summary
Systems, apparatuses, and methods are described for an inverter which receives a direct current (DC) input, and outputs an alternating current (AC) output. A high AC voltage is achieved by serially connecting AC outputs from inversion modules included in the inverter. Multiple inversion stages are serially connected in order to form the AC output. Windings around a common core of the inverter may cause ripple currents to be shared by the inversion modules. Utilizing a common core enables reducing low frequency ripple currents.