Programmable PFC Rectifier with Dynamic Voltage Control
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Solution Overview
Problem
Conventional power factor correction (PFC) rectifiers with constant output voltage are not suited for emerging applications requiring programmable outputs, leading to increased size and volume due to larger reactive components and reduced efficiency, as well as significant degradation in dynamic response and cost.
Innovation Solution
A PFC rectifier design incorporating a flyback converter in discontinuous conduction mode with a non-symmetric capacitive divider and a buck converter in the downstream stage, where the top capacitor provides high voltage for hold-up time and dynamic response, and the bottom capacitor dynamically adjusts power processing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional constant output voltage PFC rectifier designs are used for programmable output applications, then the output voltage can be regulated, but the size and volume of reactive components must increase significantly
Solution Approach 1:
The patent implements dynamic output voltage adjustment by controlling the switch node voltage to match the desired output voltage level. The system transitions from static constant voltage regulation to dynamic programmable voltage control, allowing the output voltage to be adjusted in real-time based on load requirements without requiring oversized reactive components for each fixed voltage level.
Solution Approach 2:
The patent changes the operating parameters of the PFC rectifier by adjusting the switch node voltage level dynamically. By controlling the voltage at the switch node to match the desired output voltage, the system can provide multiple output voltage levels (e.g., 5V, 12V, 20V) using the same reactor and capacitor components, eliminating the need for multiple component sets for different voltage levels.
2Adaptability or versatility
If conventional constant output voltage PFC rectifier designs are used for programmable output applications, then the output voltage can be regulated, but power processing efficiency degrades significantly
Solution Approach 1:
The patent implements dynamic efficiency optimization by continuously adjusting the switch node voltage to match the desired output voltage level. This dynamic control allows the system to operate at optimal efficiency points across different output voltage levels, preventing the efficiency degradation that would occur with fixed-design converters operating outside their optimal range.
Solution Approach 2:
The patent optimizes power processing efficiency by changing the operating voltage parameters dynamically. By controlling the switch node voltage to match the load requirements, the system minimizes power losses in the reactor and switching elements, maintaining high efficiency across different output voltage levels rather than operating at fixed suboptimal points.
3Adaptability or versatility
If conventional constant output voltage PFC rectifier designs are used for programmable output applications, then the output voltage can be regulated, but dynamic response degrades significantly
Solution Approach 1:
The patent implements fast dynamic response by using direct voltage control of the switch node to track the desired output voltage level. When the load changes or the desired output voltage changes, the system can rapidly adjust the switch node voltage and corresponding current to match new requirements, providing fast transient response without the delays associated with conventional fixed-voltage designs.
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 reduces the size and volume of the downstream stage, maintains tight output regulation, and optimizes efficiency without sacrificing dynamic response, using a non-symmetric capacitive divider to minimize the need for large energy storage capacitors and reduce the overall cost and size of the PFC rectifier.
Implementation Method 1
the top capacitor is operable to store energy at a sufficiently high voltage to provide hold up time and increase a current slew rate during transients to provide a fast dynamic transient response
Implementation Method 2
the bottom capacitor is operable to dynamically adjust on-line power processing and regulate the efficiency of a downstream stage of the PFC rectifier
Data Source
AI summary
The present invention is a system, apparatus and method of a PFC rectifier having a programmable output voltage that does not incur a drastic penalty in the overall size or volume of the device, or a significant degradation in efficiency. The PFC rectifier of the present invention may incorporate a two-stage solution for output voltage regulation. The present invention provides a topology of a small-size/volume PFC rectifier with a variable (i.e. programmable) output voltage and a complementary control method. The two-stage system of the present invention incorporates a smaller and lower cost capacitor than the bulky size and costly energy storage capacitors required in conventional prior art. The present invention also achieves tight output regulation. The two-stage topology of the present invention further achieves on-line efficiency optimization and significantly reduces the volume of the downstream stage over the prior art examples through dynamic adjustment of the downstream stage supply voltage.