Isolated Power Converter Transient Control via Half-Cycle Adjustment
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Solution Overview
Problem
Current isolated power converters face challenges in handling transient load conditions, particularly in balancing inductor currents and preventing transformer core saturation, which limits their use in dynamic applications like CPU powering.
Innovation Solution
The method involves switching primary side switch devices of the isolated power converter at an initial switching period with equal positive and negative half cycles, followed by symmetrically reducing the duration of these half cycles during transient load conditions to balance currents and prevent saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the duty cycle is locked for the primary side during each half cycle to maintain current balance, then inductor current balance is improved, but transient response becomes sluggish with reaction time up to one switching period
Solution Approach 1:
The patent applies dynamics by making the half-cycle duration adjustable rather than fixed. The controller dynamically modifies the duration of positive and negative half-cycles based on detected current imbalance conditions, allowing the system to adapt between maintaining strict balance and responding quickly to transients.
Solution Approach 2:
The patent changes the parameter of half-cycle duration to resolve the contradiction. By varying this parameter based on system state (balanced vs. unbalanced conditions), the system achieves both current balance when needed and fast transient response when required, without being constrained by a fixed duty cycle.
2Use of energy by moving object
If high value inductors with lower saturation limits are used to achieve high efficiency, then efficiency is improved, but inductor saturation occurs during dynamic load transients due to current imbalance
Solution Approach 1:
The patent applies preliminary action by detecting current imbalance conditions and adjusting half-cycle durations before saturation can occur. The controller proactively modifies operating parameters to prevent the harmful effect of saturation, rather than reacting after saturation has occurred.
Solution Approach 2:
The patent applies preliminary anti-action by taking corrective action (adjusting half-cycle durations) in response to detected imbalance conditions before saturation occurs. This prevents the adverse effect of saturation while allowing the system to operate with high-value inductors for efficiency.
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 faster transient response and prevents inductor saturation, allowing isolated power converters to handle dynamic load conditions effectively, even in lower power applications like CPU powering.
Implementation Method 1
switching primary side switch devices of the isolated power converter at an initial switching period having a positive half cycle and a negative half cycle to transfer energy across a transformer of the isolated power converter
Data Source
AI summary
An isolated power converter includes primary side switch devices coupled to secondary side rectifying devices by a transformer and a controller. Responsive to a transient load condition, the controller switches the primary side switch devices at an initial switching period having a positive half cycle and a negative half cycle to transfer energy across the transformer during the positive half cycle and the negative half cycle. The positive half cycle and the negative half cycle of the initial switching period have the same initial duration. The controller is further operable to symmetrically reduce the duration of the positive half cycle and the negative half cycle for at least one subsequent switching period during the transient load condition.