H-Bridge Transformer Voltage Control for Compact Power Adapters
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Solution Overview
Problem
Power adapters designed for electronic devices face challenges in efficiently managing transformer voltage due to the physical size of high voltage components required for power factor correction (PFC) circuits, which occupy significant space and interfere with other design considerations.
Innovation Solution
The use of an H-bridge coupled to the primary coil of a transformer, controlled by a controller that adjusts the voltage across the primary coil through switches S1 to S4, allowing for efficient voltage management and reduction of transformer flux buildup, thereby minimizing the size of high voltage components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a power factor correction circuit is used to step-up input voltage, then power factor correction is improved, but the adapter volume increases due to large high voltage components
Solution Approach 1:
The patent applies dynamic voltage control by using an H-bridge circuit with controllable switches (S1-S4) that dynamically adjust the voltage across the primary coil based on operating conditions. This dynamic control allows the system to achieve power factor correction while minimizing the required transformer flux, thereby reducing component size and adapter volume.
Solution Approach 2:
The patent changes the voltage parameter dynamically by controlling the duty cycle and switching patterns of the H-bridge. By varying the voltage across the primary coil according to the relationship V = Np * dΦ/dt, the system optimizes transformer flux levels to reduce the size of high voltage components while maintaining effective power factor correction.
2Power
If high voltage components are used for power factor correction, then voltage stepping-up capability is improved, but the physical size of components increases
Solution Approach 1:
The system uses dynamic switching control of the H-bridge to achieve voltage stepping-up only when necessary, rather than continuously maintaining high voltage. The controller adjusts switching patterns based on load conditions, reducing the required transformer flux and allowing for smaller, lighter high voltage components.
Solution Approach 2:
The patent dynamically changes voltage parameters by controlling the H-bridge switching duty cycle and pattern. This allows the system to achieve the required voltage stepping-up capability during operation while minimizing the peak flux levels that determine component size and weight.
3Volume of stationary object
If transformer flux is reduced to minimize component size, then adapter compactness is improved, but voltage control becomes more challenging
Solution Approach 1:
The patent incorporates feedback control mechanisms where the controller monitors operating conditions and adjusts the H-bridge switching patterns accordingly. This feedback system maintains precise voltage control despite reduced transformer flux, managing the complexity through intelligent control algorithms that optimize switching based on real-time conditions.
Solution Approach 2:
The H-bridge circuit acts as an intermediary between the input voltage source and the transformer primary coil. It provides precise voltage control and waveform shaping that enables effective power factor correction and voltage management even with reduced transformer flux levels, simplifying the overall control requirement.
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 approach enables compact power adapters by effectively managing transformer voltage, reducing the size of high voltage components and improving power factor correction, thus optimizing adapter design and performance.
Implementation Method 1
The H-bridge is coupled to a primary coil of a transformer. The controller controls a voltage across the primary coil of the transformer.
Data Source
AI summary
Embodiments of an adapter are disclosed that include a transformer with a primary coil coupled to an H-bridge. The H-bridge is controlled by a control circuit that controls a voltage across the primary coil using the H-bridge, and the control circuit is configured to control the H-bridge so that during each of one or more intervals, a first voltage pulse is applied across the primary coil in a start direction, wherein the start direction alternates between a first direction and a second direction each interval. Then, a direction of subsequent voltage pulses across the primary coil is alternated between the first direction and the second direction a predetermined number of times. After the predetermined number of times, a last voltage pulse is applied across the primary coil; then, voltage across the primary coil is reduced to zero for a predetermined time.