Ripple-Compensation Control for DC Voltage Stability
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Solution Overview
Problem
Existing electrical energy conversion devices face challenges in achieving power balance between the DC and AC sides without degrading controller gain performance and increasing harmonic distortion.
Innovation Solution
A ripple-compensation control method and device that generates a command value based on the ripple-component voltage from the AC side, allowing the controller to adjust the DC side voltage, thereby improving power balance while maintaining controller gain performance and reducing harmonic distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the controller gain is reduced to control DC side voltage to approach a DC constant, then the voltage stability is improved, but the power balance between DC and AC sides deteriorates and harmonic distortion increases
Solution Approach 1:
The control approach is segmented into two independent parts: a low-gain controller for DC voltage stability and a ripple-compensation controller for power balance. The ripple-compensation controller specifically targets the AC ripple component to generate compensating power commands, allowing the main controller to maintain low gain without causing power imbalance or harmonic distortion.
Solution Approach 2:
The ripple-compensation controller acts as an intermediary between the DC voltage control and the power balance requirement. It detects the AC ripple voltage and generates compensating power commands that mediate the conflict between maintaining DC voltage stability with low gain and achieving proper power balance, thereby reducing harmonic distortion.
2Stability of the object's composition
If the controller gain is reduced to control DC side voltage to approach a DC constant, then the voltage stability is improved, but the power balance between DC and AC sides deteriorates
Solution Approach 1:
The control function is segmented such that the main controller handles DC voltage stability with low gain, while a separate ripple-compensation controller handles power balance by processing the AC ripple component independently and generating compensating power commands.
Solution Approach 2:
The ripple-compensation controller serves as an intermediary mechanism that translates AC ripple voltage information into compensating power commands, thereby maintaining power balance between DC and AC sides even when the main controller operates with reduced gain for voltage stability.
3Productivity
If larger capacitors are used to improve power balance, then the energy storage capacity is improved, but the device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical/electrical solution of using larger capacitors with a control-theory-based solution. The ripple-compensation controller uses feedback from the AC ripple voltage to generate compensating power commands, substituting active control for passive energy storage enhancement.
Solution Approach 2:
Instead of changing the physical parameter of capacitor size, the patent changes the control parameter by introducing ripple-component-based compensation commands. This allows power balance to be achieved through control parameter adjustment rather than hardware parameter changes.
Data Source
AI summary
A ripple-compensation control method and electrical energy conversion device utilizing the same are provided. The ripple-compensation control method is disclosed, adopted by an electrical energy conversion device including a converter configured to perform electrical energy conversion, a controller coupled to control terminals of the converter and controlling a first voltage of a DC node of the converter according to a command value, and a ripple-compensation unit configured to generate a ripple-component voltage of the first voltage and provide the command value generated based on the ripple-component voltage to the controller.