Frequency Converter Inductance for Plasma Sterilization Harmonic Filtering
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Solution Overview
Problem
Frequency converters are limited in their ability to drive capacitive loads and are prone to burnout due to harmonic waves, especially when used in high-voltage electric field low-temperature plasma cold sterilization systems, where they cannot adjust voltage and frequency independently and are susceptible to noise and high-frequency harmonic waves.
Innovation Solution
A high-voltage electric field low-temperature plasma cold sterilization system circuit is designed with a frequency converter connected to a first-stage inductance to stabilize harmonic currents and a voltage adjustment module connected to a second-stage inductance to prevent negative resistance effects, ensuring stable operation and long-term reliability by filtering noise and high-order harmonic waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a frequency converter is directly connected to plasma discharge loads, then voltage and frequency can be adjusted, but the frequency converter is prone to burnout due to harmonic waves and cannot drive capacitive loads
Solution Approach 1:
The patent introduces an intermediary circuit between the frequency converter and plasma discharge loads, consisting of a bridge circuit with controllable switches and reactive elements. This intermediary circuit acts as a mediator that converts the frequency converter's output into a suitable form for driving capacitive plasma loads, enabling the frequency converter to drive plasma loads reliably while protecting against harmonic waves and burnout
2Productivity
If a frequency converter is used for plasma sterilization, then sterilization efficiency is improved, but harmonic waves cause burnout of the frequency converter and voltage adjustment module
Solution Approach 1:
The patent converts the harmful harmonic waves generated by plasma discharge into useful controlled switching actions. The bridge circuit with controllable switches captures the harmonic energy and redirects it through reactive elements, transforming the harmful harmonic waves into beneficial current patterns that sustain plasma discharge while protecting the frequency converter from damage
Solution Approach 2:
The bridge circuit serves as an intermediary that isolates the frequency converter from the harmful effects of plasma discharge harmonics. This intermediary circuit filters and conditions the electrical signals, allowing efficient plasma generation while protecting upstream components from harmonic damage
3Ease of operation
If voltage adjustment is performed in plasma charging process, then voltage control is achieved, but negative resistance effect occurs causing unstable operation
Solution Approach 1:
The patent changes the electrical parameters of the circuit by introducing reactive elements (inductors and capacitors) into the bridge circuit. These reactive elements modify the impedance characteristics and resonant properties of the circuit, enabling voltage adjustment while preventing the negative resistance effect that would otherwise cause instability during plasma charging
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 system achieves stable output voltage and harmonic filtering, preventing burnout and ensuring reliable operation of the frequency converter and voltage adjustment module, allowing for efficient plasma generation and effective sterilization.
Implementation Method 1
a frequency converter externally connected to a first-stage inductance, so that noise waves and high-frequency high-order harmonic waves of a power source are effectively filtered
Implementation Method 2
The plasma is formed by ionized conductive gas, which includes six types of typical particles, namely, electrons, positive ions, negative ions, atoms or molecules in an excited state
Implementation Method 3
High-voltage electric field low-temperature plasma cold sterilization is a new food cold sterilization technology
Implementation Method 4
to reach a sterilization effect by exciting medium gas around food to generate photoelectrons, ions, and reactive free radicals to come in contact with surfaces of microbes so as to damage cells of the microbes
Implementation Method 5
Ions, electrons, atoms and molecules in an excited state, and free radicals enriched in a low-temperature plasma space are all active particles, and can react with surfaces of materials easily
Data Source
AI summary
The present invention discloses a high-voltage electric field low-temperature plasma cold sterilization system circuit and apparatus, and belongs to the field of frequency converter power source circuit technologies. The present invention including a power source module, a voltage/current/power adjustment module, a switch module, and a transformer module. The power source module includes a single-phase frequency converter and a first-stage inductance. An inductance is connected in series between the output end of the frequency converter and a voltage regulator, to play a role of a reactor, harmonic components in sine pulse width modulation waves outputted by the frequency converter are effectively restrained, and spectrum is expanded, so that a harmonic current entering the voltage adjustment module is stable, and heat losses of the voltage adjustment module are reduced to prevent burnout