Single-Stage AC to DC Power Conditioning Unit with PWM Control
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Solution Overview
Problem
Existing AC to DC conversion systems using two-stage rectifiers and voltage regulators are inefficient in energy usage, generate excessive heat, and have reduced operational reliability due to continuous current flow through diodes, especially in high-temperature environments like near internal combustion engines.
Innovation Solution
A single-stage power conditioning unit with a diode and a switching device per phase leg, controlled by a controller to manage AC current polarity and voltage, reducing diode current duration and using a filter to regulate DC output voltage within a specific range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two-stage rectifiers and voltage regulators are used for AC to DC conversion, then voltage regulation capability is achieved, but energy consumption increases and heat generation increases
Solution Approach 1:
The patent combines the rectifier and voltage regulator functions into a single integrated circuit that performs both AC to DC conversion and voltage regulation simultaneously. This single-stage design eliminates the need for separate two-stage components, reducing energy losses associated with multiple conversion stages while maintaining effective voltage regulation capability.
Solution Approach 2:
The invention employs pulse-width modulation (PWM) with periodic switching of electronic switches to control power flow and regulate output voltage. The periodic switching allows precise control of energy transfer from AC input to DC output, improving energy efficiency compared to continuous operation in traditional two-stage systems.
2Reliability
If two-stage rectifiers and voltage regulators are used, then voltage control is achieved, but heat generation increases
Solution Approach 1:
By merging rectification and voltage regulation into one stage, the patent eliminates redundant energy conversion steps that generate heat in traditional two-stage systems. The integrated design reduces total power losses and associated heat generation while maintaining effective voltage control.
Solution Approach 2:
The periodic PWM switching controls power transfer in discrete pulses rather than continuous flow, allowing better thermal management. The duty cycle control enables precise voltage regulation with reduced energy losses and lower heat generation compared to continuous operation in conventional systems.
3Productivity
If diodes are used continuously in rectifier circuits, then AC to DC conversion is achieved, but operational reliability decreases in high-temperature environments
Solution Approach 1:
The patent replaces traditional diode-based rectification with electronic switch-based switching (using MOSFETs or IGBTs) controlled by PWM signals. This substitution allows active control of current flow direction and duration, improving reliability in high-temperature environments by eliminating the continuous current flow through passive diodes that generates excessive heat.
Solution Approach 2:
The electronic switches operate periodically with controlled duty cycles, allowing current flow only when needed for AC to DC conversion. This periodic operation reduces continuous heat generation and improves operational reliability in high-temperature environments compared to continuous diode conduction.
4Use of energy by moving object
If single-stage power conditioning unit is used, then energy efficiency is improved, but control complexity increases
Solution Approach 1:
The patent incorporates feedback control mechanisms that monitor output voltage and adjust PWM duty cycle accordingly. This feedback system automatically regulates the single-stage power conversion process, managing control complexity through closed-loop control while maintaining high energy efficiency.
Solution Approach 2:
The single-stage power conditioning unit performs multiple functions (rectification, voltage regulation, and protection) within a unified control architecture. The PWM controller integrates these functions into a single control system, managing complexity through multi-functionality rather than separate control circuits for each function.
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 reduces energy consumption and heat generation, enhancing efficiency, reliability, and lifespan by minimizing diode current flow to less than half the AC supply duration, while also reducing component count and implementation costs.
Implementation Method 1
a first transistor opens and closes to control flow of the first phase through the first phase leg to facilitate generating the direct current electrical power at a target voltage using the alternating current electrical power
Implementation Method 2
using a filter to regulate DC output voltage within a specific range
Data Source
AI summary
A power conditioning unit used in an electrical system. The power conditioning unit includes a positive bus and a negative bus that are electrically connected to a direct current load to enable supplying direct current electrical power to the direct current load; and a first phase leg, which includes a first diode electrically connected to the positive bus, a first transistor electrically connected to the negative bus, and a first node between the first diode and the first transistor. The first node is electrically connected to an alternating current power source to enable the first phase leg to receive a first phase of alternating current electrical power from the alternating current power source and the first transistor opens and closes to control flow of the first phase through the first phase leg to facilitate generating the direct current electrical power at a target voltage using the alternating current electrical power.