Power Converter LC Filter Resonance Suppression via Feedback Control
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Solution Overview
Problem
Conventional power conversion apparatuses face challenges in suppressing harmonic noise and resonance distortion due to switching elements, which can lead to instability in input current and inefficient power conversion.
Innovation Solution
A power conversion apparatus comprising a power converter, an LC filter, and a controller that acquires and regulates an oscillation component of the current flowing through the LC filter to control the power converter, thereby suppressing resonance and improving power factor control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an LC filter is added to suppress harmonic noise from switching elements, then noise suppression is improved, but resonance distortion occurs between capacitors and reactors causing input current distortion
Solution Approach 1:
The controller detects the oscillation component in the input current and feeds back this information to regulate the output current command. This closed-loop feedback mechanism dynamically compensates for resonance effects by adjusting the power converter output based on the detected oscillation, thereby suppressing resonance distortion while maintaining noise suppression benefits
Solution Approach 2:
The invention converts the harmful oscillation component caused by resonance into a useful control signal. By detecting and utilizing the oscillation component to regulate the output current command, the system transforms the resonance problem into a basis for active compensation, turning the harmful effect into a means for achieving resonance suppression
2Power
If switching elements are used for power conversion, then power conversion capability is improved, but harmonic noise is generated
Solution Approach 1:
The LC filter acts as an intermediary between the power converter and the AC power source, absorbing the harmonic noise generated by switching elements. The filter's capacitors and reactors provide a pathway for harmonic currents, preventing them from propagating back to the power source while allowing the switching elements to continue their power conversion function
3Stability of the object's composition
If resonance suppression is achieved through filter design, then resonance is reduced, but input current distortion occurs
Solution Approach 1:
The controller continuously monitors the input current for oscillation components and uses this feedback to dynamically adjust the output current command. This real-time feedback compensation corrects input current distortion by counteracting oscillation effects, maintaining both resonance suppression and input current quality
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 minimizes resonance and harmonic noise, ensuring stable input current and efficient power conversion by dynamically adjusting the input current command based on the oscillation component, even under high impedance conditions.
Implementation Method 1
acquire an oscillation component of a current flowing through a capacitor of the LC filter
Implementation Method 2
regulate the input current command based on the oscillation component acquired by the oscillation component acquirer
Data Source
AI summary
A power conversion apparatus includes a power converter, an LC filter, and a controller. The power converter is disposed between an AC power source and a load. The LC filter is disposed between the AC power source and the power converter. The controller controls the power converter to perform power conversion control between the AC power source and the load. The controller includes a command generator, an oscillation component acquirer, a regulator, and an actuator. The command generator generates an input current command including a command of an input current of the power converter. The oscillation component acquirer acquires an oscillation component of a current flowing through a capacitor of the LC filter. The regulator regulates the input current command based on the oscillation component acquired by the oscillation component acquirer. The actuator controls the power converter based on the input current command regulated by the regulator.