Bidirectional Power Converter Startup With Internal Voltage Selection
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Solution Overview
Problem
Existing power converters face challenges in starting and operating in reversed unidirectional or bidirectional modes without sufficient voltage for the auxiliary circuit, often requiring external circuitry like voltage boosters or pre-charge circuits.
Innovation Solution
An auxiliary circuit with an input voltage selector that can choose between two voltage inputs, eliminating the need for external voltage boosters or pre-charge circuits by selecting the greater voltage for startup and operation, thereby powering the converter circuit and its components internally.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If power converters operate in reversed unidirectional or bidirectional modes, then voltage flexibility is improved, but auxiliary circuit voltage sufficiency deteriorates
Solution Approach 1:
The auxiliary circuit is designed to accept multiple voltage sources (first voltage from first terminal, second voltage from second terminal) and can selectively operate with either source. This multi-functionality allows the same auxiliary circuit to support both forward and reversed operation modes of the power converter, resolving the contradiction between voltage flexibility and voltage sufficiency.
Solution Approach 2:
The auxiliary circuit incorporates dynamic voltage selection capability, automatically or controllably switching between the first voltage source and the second voltage source based on operating conditions. This dynamic adaptation ensures the auxiliary circuit always receives sufficient voltage regardless of whether the power converter operates in forward or reversed mode, while maintaining flexibility across different operating scenarios.
2Reliability
If external voltage boosters or pre-charge circuits are added, then startup reliability is improved, but device complexity increases
Solution Approach 1:
The voltage selection functionality is merged directly into the auxiliary circuit itself, combining the voltage selection mechanism with the existing auxiliary circuit components. This integration eliminates the need for separate external voltage boosters or pre-charge circuits, achieving reliable startup in reversed modes without increasing overall device complexity.
Solution Approach 2:
The auxiliary circuit performs self-service by autonomously selecting between the first voltage and second voltage sources to power itself during different operating modes. This self-sufficient voltage selection capability removes the need for external assistance circuits, maintaining simplicity while ensuring reliable startup and operation in both forward and reversed modes.
Data Source
AI summary
Circuits and methods encompassing a power converter that can be started and operated in a reversed unidirectional manner or in a bidirectional manner while providing sufficient voltage for an associated auxiliary circuit and start-up without added external circuitry for a voltage booster and/or a pre-charge circuit—that is, with zero external components or a reduced number of external components. Embodiments include an auxiliary circuit configured to selectively couple the greater of a first or a second voltage from a power converter to provide power to the auxiliary circuit. Embodiments include an auxiliary circuit configured to select a subcircuit coupled to the greater of a first or a second voltage from a power converter to provide an output for the auxiliary circuit. Embodiments include a charge pump including a gate driver configured to be selectively coupled to one of a first voltage node or second voltage node of the charge pump.