Power Conversion Apparatus Eliminating Rectifier Stages
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Solution Overview
Problem
Conventional power conversion apparatuses experience significant efficiency losses due to multiple stages of conversion from AC to DC voltage, with existing methods involving diode bridge circuits and power factor converters resulting in overall efficiency as low as 86% even with high individual stage efficiencies.
Innovation Solution
A power conversion apparatus utilizing a controller with first and second switches, an oscillator, input voltage detector, circuit current detector, and pulse signal output unit to generate sinusoidal circuit currents, eliminating the need for full-wave rectification and power factor converters, thereby reducing component count and losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a diode bridge circuit is used for full-wave rectification, then AC voltage can be converted to DC voltage, but power loss occurs due to current flowing through two diodes in series
Solution Approach 1:
The patent extracts and eliminates the diode bridge circuit from the power conversion system. By removing this component entirely and replacing it with a switching circuit using transistors and capacitors, the forward voltage drops and power losses associated with diodes are eliminated, directly addressing the energy loss problem while simplifying the overall circuit configuration.
Solution Approach 2:
The patent substitutes the passive diode-based rectification mechanism with an active switching circuit using transistors (Q1, Q2) and capacitors (C1, C2). This replacement allows for controlled current flow paths that avoid the inherent voltage drops of diodes, reducing power loss while maintaining the rectification function.
2Loss of energy
If a power factor converter is used to increase DC voltage, then voltage can be boosted, but additional power loss occurs due to current flowing through FET and diode
Solution Approach 1:
The patent merges the voltage boosting function into the main rectification circuit by using the same switching transistors and capacitors to achieve both rectification and voltage multiplication. The capacitor C2 serves dual purposes: filtering the rectified voltage and providing voltage multiplication during the switching cycles, eliminating the need for a separate power factor converter stage and its associated losses.
Solution Approach 2:
The switching circuit components (transistors Q1, Q2 and capacitors C1, C2) perform multiple functions simultaneously: they rectify the AC input, filter the output voltage, and provide voltage multiplication. This multi-functionality eliminates the need for separate dedicated components for each function, reducing overall power loss while achieving the required voltage levels.
3Loss of energy
If a step-down converter is connected after power factor converter, then output voltage can be reduced to desired value, but additional power loss occurs in the voltage decreasing process
Solution Approach 1:
The patent performs voltage multiplication at the rectification stage itself, so the output voltage is already at or above the desired level before reaching the load. By anticipating the voltage requirement and building it in during the initial conversion stage, the system eliminates the need for subsequent step-down conversion and its associated power losses.
Solution Approach 2:
The patent removes the step-down converter from the power conversion chain by designing the rectification and voltage multiplication stages to directly produce the required output voltage. This extraction of the unnecessary voltage reduction stage eliminates the cumulative power losses that would occur in a multi-stage conversion system.
4Loss of energy
If multiple stages of power conversion are used (AC-DC, DC-DC step-up, DC-DC step-down), then voltage can be converted and regulated, but overall efficiency decreases due to cumulative power loss
Solution Approach 1:
The patent combines multiple power conversion functions (rectification, filtering, voltage multiplication, and regulation) into a single integrated circuit stage. The switching circuit with transistors Q1, Q2 and capacitors C1, C2 simultaneously performs all these functions in one unified structure, eliminating the need for separate AC-DC, DC-DC step-up, and DC-DC step-down converter stages and their associated cumulative losses.
Solution Approach 2:
The patent employs universal switching components that perform multiple power conversion functions simultaneously. The same transistors and capacitors that rectify the AC input also multiply the voltage and regulate the output, creating a multi-functional circuit that replaces three separate conversion stages and dramatically reduces overall power loss.
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
The apparatus achieves efficient power conversion with reduced component costs and noise, eliminating the need for separate rectification and power factor correction stages, resulting in higher efficiency and cost-effectiveness.
Implementation Method 1
a first semiconductor switch Q1 connected at both ends of an AC power supply 101 through an inductor L1 and a capacitor C1 connected in series, and conducting when a pulse signal turns on, and becoming nonconductive when a pulse signal turns off
Implementation Method 2
an inductor L1 and a capacitor C1 connected in series
Implementation Method 3
an inductor L1 and a capacitor C1 connected in series
Implementation Method 4
a second semiconductor switch Q2 connected at both ends of the first semiconductor switch Q1 through a smoothing capacitor C2
Data Source
AI summary
According to one embodiment, a power conversion apparatus determines a peak value of circuit current in each pulse cycle, from a corrected output voltage value by subtracting a predetermined reference voltage from an output voltage detected by the output voltage detector, and an input voltage detected by the input voltage detector. The pulse signal output unit outputs a pulse signal to the first switch when the polarity of input voltage is positive, and outputs a pulse signal to the second switch when the polarity of input voltage is negative. A pulse signal turns on in synchronization with a clock signal input from the oscillator, and is kept on until the circuit current detected by the circuit current detector reaches the peak value. A pulse signal turns off when the circuit current reaches the peak value, and turns on again in synchronization with the next clock signal.