Transformerless Switched Converter for Power Domain Isolation
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Solution Overview
Problem
Existing DC-DC converters, such as buck and boost converters, face inefficiencies at high switching frequencies and require large, expensive magnetic energy storage elements like inductors or transformers, and lack effective ground isolation between different power domains.
Innovation Solution
A transformerless switched converter system with an energy-storage component, using a reactive circuit coupled between input and output networks, and bidirectional current blocking circuitry to isolate power domains without a transformer, allowing for non-inverting output with minimal filtering and low ripple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If magnetic energy storage elements (inductors or transformers) are used in DC-DC converters, then power conversion between different voltage levels is achieved, but the physical size and cost increase significantly
Solution Approach 1:
The patent removes the magnetic energy storage element (transformer) from the power conversion circuit, replacing it with a capacitor-based energy transfer mechanism. This extraction of the magnetic component eliminates the associated size and cost problems while maintaining the essential power conversion function through capacitive coupling and switching.
Solution Approach 2:
The patent substitutes the magnetic field-based energy storage and transfer mechanism with an electric field-based capacitive system. By replacing the inductor/transformer with capacitors and switching elements, the system achieves power conversion without relying on magnetic fields, thereby eliminating the need for large magnetic components.
2Power
If boost and buck converters are used for power conversion, then voltage level transformation is achieved, but efficiency decreases at high switching frequencies
Solution Approach 1:
The patent employs periodic switching of capacitors between different circuit nodes to achieve power conversion. The switching elements (transistors) periodically connect and disconnect capacitors to transfer energy, creating a rhythmic charge-discharge cycle that enables voltage transformation with reduced losses compared to continuous magnetic field operation at high frequencies.
Solution Approach 2:
The patent changes the operating parameters by using capacitive coupling instead of inductive coupling, allowing the system to operate efficiently at higher switching frequencies. The capacitive reactance decreases with increasing frequency, enabling effective energy transfer at frequencies where traditional magnetic converters suffer from excessive losses.
3Power
If traditional DC-DC converters are used, then power conversion is achieved, but ground isolation between different power domains is not provided
Solution Approach 1:
The patent introduces a capacitor as an intermediary energy transfer element between two isolated power domains. The capacitor couples the input and output circuits electrically while maintaining ground isolation, allowing energy transfer without direct galvanic connection between the different reference grounds, thus providing both power conversion and electrical isolation.
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 provides efficient power domain isolation with reduced size and cost, maintaining high efficiency and low ripple, even at high switching frequencies, and accommodates different ground reference levels between power domains.
Implementation Method 1
the energy-storage component can include a reactive component that is coupled between the input and output networks
Implementation Method 2
the input network and the output network can include respective current blocking circuitry to facilitate bidirectional current signal blocking from the energy-storage component
Data Source
AI summary
A power domain isolation system, such as without requiring a transformer, can include a reactive circuit, an input network having first and second input nodes that are coupled in parallel with the reactive circuit via respective first and second current control circuits, and an output network having first and second output nodes that are coupled in parallel with the reactive circuit via respective third and fourth current control circuits. The first and second current control circuits can be configured to couple the reactive circuit to the input nodes when the third and fourth current control circuits are configured to electrically isolate the reactive circuit from the output nodes, and the first and second current control circuits can be configured to electrically isolate the reactive circuit from the input nodes when the third and fourth current control circuits are configured to couple the reactive circuit to the output nodes.