Multi-Output Buck Converter for Inverter Ripple Reduction
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Solution Overview
Problem
Conventional buck converters in inverter circuits suffer from high ripple currents, large choke requirements, high semiconductor load, and reduced efficiency, leading to increased cost, weight, and volume, as well as additional losses that decrease overall inverter efficiency.
Innovation Solution
The proposed inverter circuit features a buck converter with multiple outputs that can operate both in parallel and series, reducing switching losses and energy storage requirements, with each output connected via chokes and rectifying elements, allowing for static or clocked operation to achieve a stable intermediate circuit voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a conventional buck converter is used to step down variable DC voltage from solar generators, then the intermediate circuit voltage can be maintained at a constant level, but high ripple currents occur and large chokes are required
Solution Approach 1:
The patent divides the single buck converter into multiple parallel buck converters, each handling a portion of the total current. This segmentation reduces the ripple current burden on each individual converter and allows for smaller choke sizes while maintaining the same total power handling capability and voltage stability.
Solution Approach 2:
The patent combines multiple buck converters in parallel operation to achieve the desired power handling capability. By merging their outputs through proper synchronization and control, the system maintains constant intermediate circuit voltage while distributing the current load across multiple units, thereby reducing ripple currents and choke requirements.
2Speed
If a conventional buck converter is used with high switching frequencies to maintain voltage stability, then the response time is improved, but switching losses increase and efficiency decreases
Solution Approach 1:
By segmenting the power conversion task across multiple parallel buck converters, each unit can operate at optimized switching frequencies with reduced individual losses. The distributed architecture allows for better thermal management and reduced cumulative switching losses while maintaining fast overall system response.
3Adaptability or versatility
If a buck converter is used to adapt solar generator voltage to inverter requirements, then voltage matching is achieved, but additional losses reduce overall inverter efficiency
Solution Approach 1:
The patent segments the voltage adaptation function across multiple parallel buck converters, each optimized for specific operating conditions. This segmentation reduces the voltage differential each converter must handle, thereby reducing conversion losses while maintaining the overall voltage adaptation capability from variable solar generator output to stable inverter input.
4Stability of the object's composition
If a large choke is used to reduce ripple currents in a conventional buck converter, then output voltage stability is improved, but the device volume and weight increase
Solution Approach 1:
The patent segments the current handling function across multiple parallel buck converters, each with smaller chokes. The combined effect of multiple smaller chokes operating in parallel achieves the same ripple current reduction and output voltage stability as a single large choke, but with reduced total volume and weight.
5Device complexity
If a conventional single-output buck converter is used, then the circuit complexity is low, but the efficiency and power handling capability are limited
Solution Approach 1:
The patent merges multiple buck converter units in parallel to achieve enhanced power handling capability and improved efficiency. The modular design allows for scalable configuration where additional units can be added to increase capacity while maintaining relatively simple individual circuit designs and control architectures.
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 configuration results in lower losses, reduced semiconductor load, smaller components, and increased efficiency, making it suitable for solar systems by adapting to varying input voltages while maintaining efficiency and reducing dependency on input voltage.
Implementation Method 1
A part of the energy is temporarily stored in the inductor 12
Implementation Method 2
at least one rectifying element is arranged in the positive supply line and/or negative supply line of each output
Data Source
Figure 1~4
Figure 5~7
Figure 8~10
AI summary
A buck converter with improved efficiency has a common input to which a DC voltage source (10) can be connected to apply an input voltage, and two or more outputs (24a, 24b, 24c, 24d) to which a DC voltage can each be provided whose value is less than or equal to that of the input voltage. Each of the multiple outputs (24a, 24b, 24c, 24d) is connected to the common input via a positive and a negative supply line. At least one inductor (12a, 12b, 12c, 12d) is arranged in the positive and/or negative supply line of each output (24a, 24b, 24c, 24d). Furthermore, at least one switching element (14a, 14b, 14c, 14d) is arranged in the positive supply line and/or the negative supply line of each output (24a, 24b, 24c, 24d), so that the outputs (24a, 24b, 24c, 24d) of the buck converter can be operated both in parallel and in series with each other.