Transformerless Power Conversion Apparatus Switching Control
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Solution Overview
Problem
Transformerless power conversion apparatuses are inefficient due to power wastage from Zener diodes and inrush current limiting resistors, with efficiency compromised by load conditions and capacitive reactance, limiting their application to low power and specific uses.
Innovation Solution
The power conversion apparatus employs switches controlled by a switch control circuit to manage current flow in both positive and negative cycles of the AC signal, reducing wastage by optimizing the operation of switches and using an intermediate energy storing component to improve efficiency and reduce capacitive reactance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If transformerless power conversion apparatus is used, then device size and cost are reduced, but power conversion efficiency deteriorates due to power wastage from Zener diodes and inrush current limiting resistors
Solution Approach 1:
The patent removes the Zener diode from the circuit topology, extracting the harmful power-wasting component while maintaining the transformerless architecture. The voltage regulation function previously provided by the Zener diode is replaced by a switching mechanism that eliminates continuous power dissipation.
Solution Approach 2:
The patent introduces dynamic switching control to replace the static Zener diode voltage regulation. The switch operates dynamically during AC cycles to transfer energy efficiently, converting the static power-wasting approach into a dynamic energy-management system that adapts to load conditions.
2Stability of the object's composition
If Zener diode is used for voltage regulation, then output voltage is maintained, but power wastage increases as the same power is consumed irrespective of power output
Solution Approach 1:
The patent employs periodic switching action synchronized with the AC input cycles to regulate output voltage. Instead of continuous Zener diode conduction that wastes power regardless of load, the switch operates periodically to transfer energy only when needed, maintaining voltage stability while eliminating unnecessary power dissipation.
Solution Approach 2:
The switching mechanism automatically adjusts its operation based on the AC input conditions and load requirements, providing self-regulating voltage output without the continuous power draw characteristic of Zener diodes. The system serves itself by utilizing the inherent AC cycle characteristics to control energy transfer.
3Reliability
If inrush current limiting resistor is used, then capacitor inrush current is limited, but power dissipation increases due to voltage drop across the resistor
Solution Approach 1:
The patent implements preliminary switching control that anticipates and manages inrush current conditions before they occur. The switch is controlled to operate in a specific sequence during AC cycles, pre-managing the capacitor charging process to limit inrush current without requiring a continuous power-dissipating resistor.
4Power
If capacitor reactance is used for current limiting, then inrush current is controlled, but power conversion efficiency decreases due to voltage drops
Solution Approach 1:
The patent replaces the passive capacitive reactance mechanism with an active switching control system. Instead of relying on the inherent reactive impedance that causes voltage drops and power loss, the electronic switch actively manages current flow, substituting a controllable mechanical/electronic system for the passive electrical property.
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 enhances power conversion efficiency by minimizing wastage and improving tolerance to load variations, allowing for higher power output and reduced voltage drops, thus overcoming the limitations of traditional transformerless designs.
Implementation Method 1
a main path comprising a high voltage capacitor in series with the input
Implementation Method 2
first and second switches which are operative to determine when a respective one of the first and second paths carries current
Implementation Method 3
using an intermediate energy storing component to improve efficiency and reduce capacitive reactance
Data Source
Figure 1
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AI summary
The present invention relates to power conversion apparatus (40) configured to receive a high voltage alternating current (AC) signal at an input (42, 44) and to provide in dependence thereon a low voltage direct current (DC) signal from an output stage (58, 60). The power conversion apparatus (40) comprises a main path comprising a high voltage capacitor (46) in series with the input. The power conversion apparatus (40) also comprises a first path operative to carry current carried by the main path in at least one of a positive going part and a negative going part of the high voltage alternating current signal and a second path operative to carry current carried by the main path in a positive going part and a negative going part of the high voltage alternating current signal. The power conversion apparatus further comprises first and second switches (52, 54) which are operative to determine when a respective one of the first and second paths carries current. In the power conversion apparatus, the output stage (58, 60) receives current flowing in the first path and at least one of the first and second switches (52, 54) is operable in dependence on a control signal derived from the low voltage direct current signal.