Grid-Tied Inverter Clock Frequency Variation
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Solution Overview
Problem
Grid feed-in inverters generate harmonics that disrupt the supply network, leading to electromagnetic radiation and increased costs due to the need for additional circuit complexity, structural volume, and reduced efficiency in energy supply systems.
Innovation Solution
A grid feed-in inverter with a buffer capacitor and clock generator that varies the clock frequency between a lower and upper limit frequency, spreading harmonic energy across the frequency spectrum to reduce electromagnetic radiation and eliminate the need for costly mains filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If mains filters are provided to dampen harmonics, then electromagnetic radiation is reduced, but device complexity, structural volume, and cost increase
Solution Approach 1:
The patent changes the clock frequency parameter dynamically between a lower limit frequency and an upper limit frequency. This parameter change spreads the harmonic energy across a broader frequency spectrum, reducing peak harmonics and thereby reducing electromagnetic radiation without requiring additional filtering circuitry
Solution Approach 2:
The patent introduces dynamic frequency variation instead of a fixed clock frequency. The clock frequency is varied within specified limits to distribute harmonic energy over time and frequency, eliminating the need for static filtering components and reducing overall system complexity
2Object-affected harmful factors
If mains filters with inductances and capacitances are added, then harmonics are dampened, but structural volume and weight increase
Solution Approach 1:
By dynamically changing the clock frequency parameter between lower and upper limits, the patent spreads harmonic energy across the frequency spectrum. This approach reduces peak harmonic amplitudes without requiring physical filtering components, thereby maintaining compact structural volume
3Object-affected harmful factors
If mains filters are implemented, then electromagnetic radiation is reduced, but energy supply system efficiency decreases
Solution Approach 1:
The patent uses parameter changes in clock frequency to reduce electromagnetic radiation, avoiding the energy losses associated with passive filtering components. By spreading harmonic energy through frequency modulation rather than dissipating it through resistive elements in filters, the system maintains higher efficiency
Solution Approach 2:
The dynamic frequency variation approach eliminates the need for static filtering components that continuously consume energy. The system adaptively manages harmonic content through frequency modulation, reducing energy losses and improving overall system efficiency
4Object-affected harmful factors
If clock frequency is varied between lower and upper limits, then harmonic energy is spread across frequency spectrum, but clock generator complexity increases
Solution Approach 1:
The patent implements parameter changes in the clock frequency within specified limits. This approach spreads harmonic energy across the frequency spectrum while using relatively simple frequency specification units that output frequency specifications varying between lower and upper limit frequencies, avoiding complex modulation circuits
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
This approach allows for a higher proportion of energy to be fed into the supply grid without excessive electromagnetic radiation, reducing interference and the need for additional filtering, thereby improving the efficiency and reducing costs of the energy supply system.
Implementation Method 1
a frequency specification unit connected to the clock generator is also provided, which is designed to output a frequency specification to the clock generator that varies between a lower limit frequency and an upper limit frequency
Implementation Method 2
Varying the clock frequency has the effect of spreading the energy of the harmonics across the frequency spectrum, thereby attenuating peaks in the frequency spectrum
Implementation Method 3
a buffer capacitor designed to buffer electrical energy received via the connection
Data Source
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AI summary
The invention relates to a grid-tied inverter (1) and a power supply system with such a grid-tied inverter (1). The grid-tied inverter (1) has a connection for at least one DC voltage source (2), a buffer capacitor (5) configured to buffer electrical energy received via the connection, and at least one grid feed-in unit (4) connected to the buffer capacitor (5) and a clock generator (6). The grid feed-in unit (4) is configured to convert the electrical energy buffered in the buffer capacitor (5) into an AC voltage by means of a clock signal generated by the clock generator (6) at a clock frequency and to feed the AC voltage into a supply network (3). The clock generator (6) is configured to generate the clock frequency according to a frequency specification (f).According to the invention, a frequency control unit (7) connected to the clock generator (6) is also provided, which is configured to output a frequency control (f) to the clock generator (6) that varies between a lower cutoff frequency (fmin) and an upper cutoff frequency (fmax).