AC-DC Power Conversion Circuit with Harmonic Suppression
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Solution Overview
Problem
Conventional power converting apparatuses suffer from significant efficiency losses due to multiple stages of AC-DC conversion, resulting in low overall efficiency and harmonic noise emission, which is detrimental to the environment.
Innovation Solution
A power converting apparatus utilizing a power conversion circuit with N-type channel MOSFET switches, smoothing capacitors, and filters, along with a controller that generates pulse signals to manage circuit current and power supply voltage, allowing for efficient conversion of alternating current to direct current with reduced harmonic noise by operating in a single stage with a high-frequency alternating current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a power factor improving converter is added to convert AC to DC, then the power factor is improved, but the device complexity and number of stages increase
Solution Approach 1:
The patent merges the AC-DC conversion and DC-DC conversion into a single integrated power conversion circuit. The circuit uses N-channel MOSFETs as switching elements and includes a capacitor connected between the source terminals of the MOSFETs. This unified structure performs both power factor improvement and voltage conversion in one stage, eliminating the need for separate PFC circuits and reducing overall system complexity.
Solution Approach 2:
The power conversion circuit is designed to perform multiple functions simultaneously: it acts as both an AC-DC converter and a DC-DC converter. The circuit can operate in different modes depending on the switching control, achieving both power factor correction and voltage step-up/step-down in a single universal structure that adapts to different operating conditions.
2Object-generated harmful factors
If multiple conversion stages are used to improve power factor, then the power factor is improved, but the conversion efficiency deteriorates
Solution Approach 1:
The patent combines AC-DC conversion and DC-DC conversion into a single power conversion circuit stage. This eliminates the cumulative power losses that occur in multi-stage conversions (e.g., 0.95×0.95×0.95=0.86 for three stages). The unified circuit achieves both power factor improvement and voltage conversion in one process, maintaining higher overall efficiency by avoiding repeated conversion losses.
3Device complexity
If conventional AC-DC conversion is used, then the circuit is simple, but harmonic noise is emitted to the environment
Solution Approach 1:
The patent integrates AC-DC conversion and DC-DC conversion in a single circuit stage, which inherently suppresses harmonic noise. The unified power conversion circuit processes the input current in one continuous operation rather than through multiple discrete conversion stages, reducing the generation and propagation of harmonic disturbances to the power supply system.
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 achieves high-efficiency power conversion with reduced harmonic noise, enabling stable and efficient electric power supply to loads while minimizing equipment size and cost.
Implementation Method 1
a power conversion circuit (11-1) including: first and second switches (S1, S2) each of which is an N-channel MOSFET
Implementation Method 2
first and second smoothing capacitors (C1, C2)
Data Source
AI summary
A controller outputs a pulse signal to a first switch and a second switch on the basis of a circuit current flowing through a power conversion circuit and a voltage of an alternating-current power supply. The first switch and the second switch alternately open and close. According to the opening and closing, an electric current in which a high-frequency current is mixed with a low-frequency component of the alternating-current power supply flows to the power conversion circuit.