VSCF Converter Voltage Control for Abnormal Overload Loss Reduction
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Solution Overview
Problem
Conventional VSCF converter systems face thermal stress and increased power switch losses during abnormal overload conditions due to reduced point of regulation voltage, which affects the delivery of AC power to loads.
Innovation Solution
A method and system for controlling a VSCF converter that includes comparing sensed DC voltage and AC current to predetermined limits, adjusting the DC voltage reference, and controlling the generation of variable frequency AC voltage to reduce DC voltage during abnormal overload conditions, thereby minimizing thermal stress and power switch losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the point of regulation voltage is reduced during abnormal overload conditions, then the thermal stress on the VSCF converter is reduced, but the power delivery capability to loads deteriorates
Solution Approach 1:
The patent implements dynamic adjustment of the point of regulation voltage based on real-time detection of overload conditions. The controller dynamically modifies the DC voltage reference signal to reduce voltage during abnormal overload conditions, thereby dynamically managing thermal stress while attempting to maintain power delivery capability through coordinated control of both DC and AC stage voltages.
Solution Approach 2:
The patent changes the voltage parameter (point of regulation voltage) in response to detected overload conditions. By detecting when AC output current exceeds a predetermined threshold and subsequently reducing the DC voltage reference signal, the system changes operational parameters to manage thermal stress during abnormal conditions.
2Loss of energy
If the DC voltage is reduced during abnormal overload, then power switch losses are minimized, but the ability to maintain constant frequency AC power output deteriorates
Solution Approach 1:
The patent employs feedback control by continuously monitoring the AC output current and comparing it against predetermined thresholds. Based on this feedback, the controller adjusts the DC voltage reference signal to reduce power switch losses during overload conditions while attempting to maintain reliable constant frequency output through coordinated AC stage control.
Solution Approach 2:
The patent takes preliminary action by detecting overload conditions before they cause excessive thermal damage. The controller proactively reduces the DC voltage reference signal when abnormal conditions are detected, preventing excessive power switch losses before they occur, while maintaining system reliability through coordinated voltage control.
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 solution effectively reduces maximum operating temperatures of power switches and maintains current delivery during abnormal overload conditions, extending the operational range and reducing stress on the converter.
Implementation Method 1
The VSCF converter can include a generator that receives the variable-speed motive power, and converts the motive power into a variable-frequency AC power at an output thereof.
Implementation Method 2
An alternating current (AC)/direct current (DC) stage can convert the variable frequency AC power into a DC voltage.
Implementation Method 3
A DC/AC stage can convert the DC voltage into a fixed frequency AC power that can be output to an AC bus for use by one or more loads.
Data Source
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AI summary
A method of controlling a variable speed constant frequency (VSCF) power converter is provided. The method includes receiving a determination that a sensed AC current output has exceeded a predetermined limit. The AC current output is converted from a DC voltage and has a constant frequency. The DC voltage is converted from a variable frequency AC voltage. The variable frequency AC voltage is generated in response to a mechanical energy input having a varying parameter. The method further includes decreasing the DC voltage in response to a determination that the sensed AC current output has exceeded the predetermined limit.