Isolated DC/DC Converter Control to Prevent Transformer Saturation
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Solution Overview
Problem
Existing isolated DC/DC converters face transformer saturation issues due to uneven duty-cycles of switches and unequal voltage drops, which are not effectively addressed by passive or active approaches that increase size, cost, or complexity.
Innovation Solution
A control method that enables and disables switches in alternating durations to reset the DC magnitude of magnetizing current to zero, preventing transformer saturation without additional capacitors, sensors, or auxiliary windings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a series DC blocking capacitor is used to prevent transformer saturation, then transformer saturation is prevented, but the converter size and cost increase
Solution Approach 1:
The patent extracts and eliminates the DC blocking capacitor from the circuit by using a control method that disables switches for a specific duration to reset the DC magnitude of magnetizing current to zero, thereby preventing transformer saturation without the capacitor
Solution Approach 2:
The control method uses the existing switch circuitry to self-reset the magnetizing current by disabling the switches for a predetermined time period, allowing the system to prevent saturation using its own components without additional external elements
2Reliability
If a series DC blocking capacitor is used to prevent transformer saturation, then transformer saturation is prevented, but the converter cost increases
Solution Approach 1:
The patent removes the DC blocking capacitor from the bill of materials by implementing a control-based solution that uses existing switch and control circuitry to achieve saturation prevention, thereby reducing component count and manufacturing cost
3Reliability
If a transformer is designed with a large air gap to prevent saturation, then transformer saturation is prevented, but the transformer size increases
Solution Approach 1:
The patent changes the operational parameters of the transformer by introducing a disabling duration that resets the DC magnitude of magnetizing current to zero, allowing the use of smaller transformers without large air gaps since saturation is prevented through control rather than physical design modifications
4Reliability
If magnetic flux-density transducer or current sensors are used to regulate magnetizing current, then transformer saturation is prevented, but the converter cost and complexity increase
Solution Approach 1:
The control method uses the existing current information already available in the switch circuitry to determine when to disable the switches, allowing the system to self-regulate the magnetizing current without requiring additional magnetic flux-density transducers or current sensors
Data Source
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AI summary
A power converter and a control method thereof are provided. The power converter includes a primary side switching circuit (1), a secondary side switching circuit (2), a transformer (TR), and a control circuit (2). The primary side switching circuit (1) includes a first set of switches. The secondary side switching circuit (2) includes a second set of switches. The transformer (TR) is coupled between the primary side switching circuit (1) and the secondary side switching circuit (2). The control circuit (3) is configured to control power transfer between the primary side switching circuit (1) and the secondary side switching circuit (2) by controlling the first and second sets of switches. The control circuit (3) is adapted to enable and disable the first and second sets of switches in an enabling duration and a disabling duration respectively and alternatively.