DC to AC Power Converter Ripple Reduction via Phase Shifting
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Solution Overview
Problem
Conventional power conversion systems experience inefficiencies due to AC ripple currents when converting DC power to AC power, leading to increased component costs and reduced system lifespan, as they require filtering and modified switching frequencies to mitigate these currents.
Innovation Solution
The system employs a controller to phase shift and combine DC power signals from multiple input stages, reducing AC ripple currents by interleaving currents and adjusting duty cycles or frequencies, thereby minimizing conductive losses and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If switching type electronic systems are used to condition DC power, then power conversion capability is improved, but AC ripple current increases causing conductive losses
Solution Approach 1:
The power conversion system is divided into multiple parallel converter stages (first converter stage, second converter stage, etc.), each processing a portion of the input current. By segmenting the total current into multiple parallel paths with phase-shifted switching, the peak ripple current in each stage is reduced, and the combined output has attenuated ripple characteristics compared to a single-stage converter.
Solution Approach 2:
Multiple converter stages are combined in parallel to form a composite power conversion system. The output currents from individual stages are merged together, where the phase-shifted ripple components partially cancel each other out, resulting in a combined output with reduced AC ripple current and lower conductive losses.
2Loss of energy
If filters are employed to limit AC ripple current, then conductive losses are reduced, but component cost increases
Solution Approach 1:
The system uses the switching actions of the converter stages themselves to generate phase-shifted currents that inherently reduce ripple content. The converters' own operational characteristics are leveraged to achieve ripple reduction without requiring external filtering components, making the system self-regulating in terms of ripple current management.
Solution Approach 2:
The switching frequency or duty cycle of individual converter stages is adjusted to create phase shifts between stages. By changing the temporal parameters of switching operations rather than adding physical filtering elements, the system achieves ripple current reduction through parametric control of the conversion process.
3Productivity
If conventional systems modify operation to limit AC ripple current, then system efficiency is improved, but system lifespan is diminished
Solution Approach 1:
By dividing the power conversion function across multiple parallel stages, each stage operates at reduced stress levels compared to a single-stage system. The segmentation distributes thermal and electrical stress, preventing any single component from experiencing excessive loading that would accelerate degradation and reduce overall system lifespan.
Data Source
AI summary
Embodiments of the invention can provide systems, methods, and apparatus for converting direct current (DC) power to alternating current (AC) power. According to one embodiment, a system for converting DC power to AC power can be provided. The system can include a DC power source that provides a first DC power signal to a converter. Coupled to the converter can be a controller for transforming the first DC power signal into a plurality of AC power signals. The controller can also phase shift at least one of the plurality of AC power signals and combine the phase shifted AC power signal with at least one of the other of the plurality of AC power signals to provide a second DC power signal. The controller can also convert the second DC power signal to an AC power signal.