Power Conversion Circuit Harmonic Suppression via Active State Control
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Solution Overview
Problem
Power conversion stages generate unwanted electric harmonics due to the switching behavior of power electronic devices, leading to inefficiencies and the need for bulky line filters to mitigate harmonic distortion.
Innovation Solution
A circuit arrangement featuring at least two series-connected electronic devices, including an actively controlled power electronic device that operates in multiple states (on, off, and active) to suppress harmonic generation, utilizing a controller with feedback mechanisms to regulate input current and voltage, thereby minimizing harmonic production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If power electronic devices operate in switching modes to convert electrical power, then power conversion efficiency is improved, but electric harmonics are generated causing distortion
Solution Approach 1:
The patent changes the operational parameters of power electronic devices by introducing a third operation state (active state with resistive characteristic) in addition to traditional on and off states. This parameter expansion allows the devices to operate in a manner that reduces harmonic generation while maintaining conversion efficiency. The controller dynamically adjusts the operation state based on feedback signals to optimize both efficiency and harmonic suppression.
Solution Approach 2:
The patent implements feedback mechanisms where controllers receive feedback signals from the power conversion stage and adjust the operation states of power electronic devices accordingly. This closed-loop control enables real-time suppression of electric harmonics by modulating the active state duration and resistive characteristics, thereby reducing distortion while maintaining efficient power conversion.
2Object-generated harmful factors
If line filters are added to suppress harmonic distortion, then electric harmonics are reduced, but the size and complexity of the power conversion stage increases
Solution Approach 1:
The patent extracts the harmonic suppression function from separate line filters and integrates it directly into the power electronic devices themselves. By making the power electronic devices operable in multiple states including an active resistive state, the harmonic filtering function is embedded within the switching devices, eliminating the need for bulky external line filters and reducing overall system complexity.
Solution Approach 2:
The patent merges the power conversion function and harmonic suppression function into a single integrated system. The power electronic devices perform both power switching and harmonic filtering simultaneously by operating in controlled active states, combining multiple functions into one component set and thereby reducing device complexity and space requirements.
3Object-generated harmful factors
If power electronic devices operate in active state with resistive characteristic, then electric harmonics are suppressed, but energy loss increases
Solution Approach 1:
The patent employs periodic switching between on state, off state, and active state to achieve harmonic suppression. The active state with resistive characteristic is activated periodically rather than continuously, allowing the system to maintain low energy loss during on and off states while intermittently providing harmonic suppression. This periodic operation minimizes the total energy dissipated in the resistive state.
Solution Approach 2:
The patent applies partial action by activating the active resistive state only when and where needed for harmonic suppression, rather than maintaining it continuously. The controller selectively engages the active state based on harmonic conditions, providing just enough resistive damping to suppress harmonics while minimizing energy loss during periods when harmonic suppression is less critical.
Data Source
AI summary
A circuit arrangement for use in a power conversion stage and a method of controlling a power conversion stage includes at least two electronic devices connected in series, the at least two electronic devices including at least one active power electronic device operable in a plurality of operation states including an active linearly operated state; wherein the at least one active power electronic device is arranged to be controlled and to operate in the plurality of operation states in each of a plurality conversion cycles, such that a generation of electric harmonics in the power conversion stage is suppressed during an operation of the power conversion stage.