ACDC Converter Burst Mode Control for Low No-Load Power
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Solution Overview
Problem
Existing ACDC converters face challenges in achieving low no-load power consumption while maintaining high efficiency, due to issues with standby or no-load losses and magnetic core losses, and require Power Factor Correction (PFC) and energy storage capabilities to handle varying line voltages.
Innovation Solution
An ACDC converter design utilizing burst mode control with a controller that provides a pulse set to achieve zero net magnetizing current, combined with a buck converter for PFC and a transformer stage with self-driven synchronous rectifiers, allowing for efficient operation and reduced no-load power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional ACDC converter designs are used, then power factor correction and voltage transformation are achieved, but no-load power consumption and magnetic core losses are too high
Solution Approach 1:
The patent applies periodic action by implementing burst mode control where the converter operates in discrete bursts rather than continuously. The controller activates the converter in periodic bursts during light-load conditions, allowing the magnetic core to demagnetize completely between bursts, thereby reducing magnetic core losses while maintaining power factor correction capability through the periodic activation pattern
2Loss of energy
If the converter operates continuously to maintain output voltage, then stable output is achieved, but switching losses and magnetic core losses increase
Solution Approach 1:
The patent applies dynamics by implementing a dynamic control strategy that adapts the converter's operation mode based on load conditions. The controller dynamically switches between burst mode (for light loads) and continuous mode (for heavy loads), optimizing the balance between switching losses and output voltage stability by adjusting the duty cycle and activation patterns according to real-time demand
3Loss of energy
If burst mode control is implemented to reduce no-load losses, then no-load power consumption decreases, but control complexity increases
Solution Approach 1:
The patent applies self-service by implementing a control system that automatically monitors load conditions and adjusts its own operation mode without external intervention. The controller self-regulates by detecting output current levels and autonomously switching between burst mode and continuous conduction mode, reducing the need for complex external control circuitry while achieving low no-load power consumption
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 design achieves optimal transformer utilization, reduces no-load power consumption, and maintains high efficiency by controlling the converter's operation to minimize switching and magnetic core losses, while providing effective PFC and energy storage capabilities.
Implementation Method 1
the controller operates using burst mode control and the control signal further comprises a pulse set designed to provide substantially zero net magnetising current in the double-ended converter
Implementation Method 2
the control signal further comprises a pulse set designed to provide substantially zero net magnetising current in the double-ended converter
Implementation Method 3
a DC transformer stage comprising a transformer input stage and a transformer output stage
Implementation Method 4
a transformer stage with self-driven synchronous rectifiers
Data Source
AI summary
This invention relates to an ACDC converter (1) comprising a converter input (3) and a converter output (5), a pre-regulation stage (7) and a DC transformer stage (9) comprising a transformer input stage (11) and a transformer output stage (13). The transformer input stage comprises a double ended converter and there is further provided a controller (17) for providing a control signal to the double ended converter. The controller (17) operates the ACDC converter using burst mode control and by sending control signals comprising pulse sets that are designed to provide substantially zero net magnetising current in the double ended converter. The pre-regulation stage preferably comprises a buck converter which in turn also provides power factor correction to the input of the ACDC converter.