Power Conversion Device Using Line-Frequency Periodic Control
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Solution Overview
Problem
Conventional power conversion devices experience reduced efficiency due to frequent switching of active switch elements under high-frequency control signals, leading to increased power dissipation when converting direct-current voltage to alternating current.
Innovation Solution
A power conversion device and control method that utilize a control signal with a frequency matching the AC voltage, reducing switching times and incorporating a power conversion unit with a DC to AC conversion circuit and immitance conversion circuit to generate high-frequency currents, which are then rectified and filtered to produce an alternating current synchronous with the AC voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high-frequency control signals are used to control active switch elements, then the switching frequency is increased, but power dissipation increases and conversion efficiency decreases
Solution Approach 1:
The patent applies periodic action by using a control signal with the same frequency as the AC voltage (50-60 Hz) to drive the active switch elements, replacing the conventional high-frequency switching approach. This periodic control at line frequency reduces switching losses while maintaining effective power conversion, directly resolving the contradiction between switching frequency and power dissipation.
2Speed
If high-frequency control signals are used to control active switch elements, then the switching frequency is increased, but conversion efficiency decreases
Solution Approach 1:
The patent uses periodic control at AC line frequency (50-60 Hz) instead of high-frequency switching, which reduces switching losses and improves overall conversion efficiency while maintaining the required power conversion functionality.
3Device complexity
If conventional power conversion devices are used, then the circuit structure is simple, but power dissipation is high and conversion efficiency is low
Solution Approach 1:
The patent implements periodic control at line frequency combined with a resonant tank circuit to achieve low-loss power conversion. This approach maintains relatively simple circuit structure while dramatically reducing power dissipation through resonant operation and reduced switching frequency.
4Productivity
If high-frequency switching is used, then the power conversion speed is improved, but the active switch elements suffer from increased power dissipation
Solution Approach 1:
The patent employs periodic control at AC line frequency with resonant tank circuits to achieve efficient power conversion without high-frequency switching. This reduces power dissipation and heat generation in active switch elements while maintaining adequate power conversion performance.
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 decreases power dissipation and enhances conversion efficiency by synchronizing the alternating current output with the AC voltage, improving power factor and system reliability while reducing the number of circuit elements and complexity.
Implementation Method 1
The inductive circuit is for providing two induced currents according to the high-frequency current, wherein one induced current and the high-frequency current are in phase, and the other one induced current and the high-frequency current are in antiphase
Implementation Method 2
The full-wave rectifying circuit is for full-wave rectifying the two induced currents
Implementation Method 3
The filter circuit is for filtering the output current to provide the alternating current
Data Source
AI summary
A power conversion device is provided for converting a DC voltage to an alternating current corresponding to an AC voltage according to the AC voltage, which includes a power conversion unit and an output unit. The power conversion unit converts the DC voltage to a high-frequency current having two envelops corresponding to the waveform of the AC voltage. The output unit includes an inductive circuit, a full-wave rectifying circuit, an inverter circuit and a filter circuit. The inductive circuit provides two induced currents according to the high-frequency current, wherein one induced current and the high-frequency current are in phase, and the other induced current and the high-frequency current are in antiphase. The full-wave rectifying circuit full-wave rectifies the two induced currents. The inverter circuit alternatively transfers the two full-wave rectified induced currents, and thus output an output current. The filter circuit filters the output current to provide the alternating current.