Boost Chopper PFC Circuit for Stable DC Voltage Under Load Changes
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Solution Overview
Problem
Existing power supply circuits with partial switching methods for power factor correction and harmonic current suppression face inefficiencies and instability in DC voltage control, particularly when power supply voltage or load conditions change, leading to potential system shutdowns.
Innovation Solution
A power supply circuit that combines a boost chopper circuit with a boost ratio stabilization control method and a boost ratio corrector, using a microcomputer to process input current and DC voltage values to dynamically adjust the duty ratio signal and boost ratio, preventing over-voltage and low-voltage protection by setting limit values for the DC voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a partial switching method is used to stop switching operation near the peak of input current, then switching loss is reduced and circuit efficiency is improved, but DC voltage becomes unstable and changes with power supply voltage and load conditions
Solution Approach 1:
The patent applies dynamics by making the boost ratio adjustable rather than constant. The controller dynamically changes the boost ratio based on detected DC voltage levels and power supply voltage conditions, allowing the system to adapt between partial switching (for efficiency) and full switching (for voltage stability) as needed.
Solution Approach 2:
The patent changes the parameter of boost ratio from a fixed constant to a variable parameter that can be adjusted by the controller. By modifying the boost ratio based on voltage detection results, the system optimizes both efficiency and stability under different operating conditions.
2Productivity
If a constant boost ratio is used in partial switching method, then switching loss is reduced, but the system cannot maintain stable operation when power supply voltage or load changes significantly
Solution Approach 1:
The patent implements feedback by using a detector to monitor DC voltage levels and feeding this information back to the controller. The controller then adjusts the boost ratio based on the detected voltage, creating a closed-loop control system that maintains stability while preserving efficiency benefits.
Solution Approach 2:
The system transitions from static constant boost ratio to dynamic adjustable boost ratio, allowing real-time adaptation to changing power supply voltage and load conditions while maintaining both efficiency and reliability.
3Stability of the object's composition
If whole-area switching method is used, then DC voltage can be controlled stably, but switching loss increases and circuit efficiency decreases
Solution Approach 1:
The patent applies partial switching by stopping the switching operation near the peak of input current where it contributes least to voltage regulation. This partial action reduces switching loss while the controller compensates by adjusting the boost ratio to maintain adequate DC voltage control.
Solution Approach 2:
By changing the boost ratio parameter dynamically, the system achieves adequate DC voltage control without requiring full-area switching, thereby reducing switching loss and improving overall circuit 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 solution maintains system stability and efficiency by suppressing voltage fluctuations, ensuring continuous operation even with changes in power supply voltage and load conditions, while optimizing power factor and harmonic current suppression.
Implementation Method 1
a rectifier circuit and a smoothing circuit, which are configured to convert AC power supply into direct current
Implementation Method 2
a boost chopper circuit which is made up with a switching element, which is configured to perform a switching operation upon basis of a duty ratio signal, as well as, an inductance and diodes
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
A power supply circuit comprises a rectifier circuit (2) and a smoothing circuit (4), which are configured to convert AC power supply into direct current, a boost chopper circuit (3) being made up with a switching element (31), which is configured to perform a switching operation upon basis of a duty ratio signal (5a), as well as, an inductance (32) and a diode (33); an input current information producing unit, which is configured to produce information of an input current, which flows therein from the AC power supply, and a controller unit (5), which is configured to produce a second coefficient from the input current information and a first coefficient preset, so as to obtain a product between the second coefficient and the input current information, and thereby producing the duty ratio signal (5a) for regulating an operation of the switching element (31), at least, upon basis of this product; further comprising: a load condition producing unit, which is configured to produce load condition information indicating a condition of a load, which is connected with the smoothing circuit (4); and a coefficient correcting unit, which is configured to correct the first coefficient with using the load condition information.