Full Bridge Inverter Phase Shift Control
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Solution Overview
Problem
Conventional phase-shifted full bridge systems experience phase deviations in output voltage, affecting the synchronization of operation timings between multiple electric devices and causing deviations in their operations due to uneven phase shifts across different output voltages.
Innovation Solution
Implementing phase shift control on both legs of a full bridge inverter in opposite directions to stabilize the overlap angle, eliminating phase deviations by canceling out phase shifts and using a control circuit with phase and voltage compensation units to adjust rectangular wave signals and output voltages accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If phase shift control is performed on only one leg (shift leg) while keeping the other leg (fixed leg) stationary, then power control is achieved through overlap angle adjustment, but phase deviation occurs in the output voltage causing unsynchronized operation timings between multiple devices
Solution Approach 1:
The patent applies asymmetry by making both legs capable of phase shifting rather than keeping one leg fixed. Each leg can independently adjust its phase, allowing symmetric phase shift control that eliminates the phase deviation problem caused by the asymmetric fixed-leg configuration. This enables multiple devices to operate in synchronization while maintaining power control capability.
Solution Approach 2:
The patent inverts the conventional approach by having both legs perform phase shifting instead of only one leg. This inversion of the fixed-leg concept allows the system to eliminate phase deviation while maintaining the ability to control output power through coordinated phase adjustment of both legs.
2Power
If different amounts of phase shift are applied to different output voltages to control power, then power distribution is adjusted, but phase deviation occurs between different output voltages causing operation timing deviations
Solution Approach 1:
The patent employs feedback mechanisms where phase detection units monitor the phase of output voltages and a phase comparison unit compares phases between different outputs. Based on this feedback, the control circuit adjusts the phase shift amounts of both legs to eliminate phase deviations, ensuring synchronized operation timings while maintaining desired power distribution.
Solution Approach 2:
The patent dynamically changes the phase shift parameter for both legs based on detected phase deviations. By continuously adjusting the phase shift amount of each leg in response to measured phase differences, the system maintains phase synchronization across multiple outputs while achieving the desired power distribution.
Data Source
AI summary
In this power conversion device, a phase deviation of an output voltage due to a phase shift control is eliminated. The power conversion device according to the present invention converts DC voltage to AC voltage by phase-shift controlling the switching elements of a full bridge inverter. In place of a conventional method in which only one of the first and second legs of the full bridge inverter is phase-shifted, both legs are phase-shifted in opposite directions to each other to control an overlap angle at which the switching elements of the first and second legs of the full bridge are simultaneously brought into an on-state. The variation of the center phase of the overlap angle is suppressed by phase-shifting the first and second legs in the opposite directions to each other.