DC Bus Stabilizer Architecture for Renewable Power Fluctuations
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Solution Overview
Problem
Power systems utilizing renewable energy sources like solar and wind face significant power variation due to weather and seasonal changes, necessitating a DC bus control system that efficiently manages power fluctuations while minimizing the size, complexity, and cost of the power converter.
Innovation Solution
A DC bus control system incorporating a main stabilizer and sub-stabilizers with charge/discharge elements and power converters to maintain bus voltage and current targets, using a monitor/instruction device for state monitoring and operation control, allowing efficient charging and discharging to stabilize the DC bus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a power converter with large capacity is used to maintain DC bus voltage within allowable range, then the voltage stability is improved, but the system size, complexity, and cost increase
Solution Approach 1:
The patent divides the single large-capacity power converter into multiple smaller power converters (first power converter connected to solar cells, second power converter connected to wind-force power generator, and auxiliary power converter connected to storage device). Each converter handles a portion of the power conversion task, collectively maintaining DC bus voltage stability without requiring any single converter to have large capacity, thus reducing system complexity and cost while improving reliability
2Productivity
If a power converter with large capacity is used to handle power variation, then the power management capability is improved, but the system cost increases
Solution Approach 1:
The patent segments the power management function across multiple specialized converters: the first and second power converters handle renewable energy input, the auxiliary power converter manages storage device charging/discharging, and the third power converter handles AC power conversion. This segmentation enables efficient power management for varying renewable energy inputs without requiring any single expensive large-capacity converter, reducing overall system cost while maintaining high productivity
Solution Approach 2:
The storage device acts as an intermediary energy buffer between renewable energy sources and the load. It absorbs excess energy when generation exceeds demand and releases energy when generation is insufficient, enabling effective power management without requiring oversized power converters, thus improving productivity while controlling system cost
3Reliability
If the DC bus voltage is maintained within a narrow allowable range, then the voltage stability is improved, but the adaptability to power variation decreases
Solution Approach 1:
The patent implements dynamic voltage control where the DC bus voltage target value is adjusted based on the charge/discharge state of the storage device. When the storage device is in a specific charge/discharge state, the control unit sets the DC bus voltage target to a first value; when in another state, it sets to a second value. This dynamic adjustment allows the system to maintain voltage stability within acceptable ranges while adapting to varying power conditions from renewable sources and load demands
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 effectively stabilizes the DC bus voltage and current, enhancing efficiency in power management and reducing the need for large-capacity converters, thereby minimizing system size and cost.
Implementation Method 1
a power converter having a wide input range and a large capacity
Implementation Method 2
a main stabilizer including a first charge/discharge element and a first power converter; and a plurality of sub-stabilizers each including a second charge/discharge element
Data Source
AI summary
A direct-current bus control system is provided for controlling power variation in a DC bus connecting an input power source and a load, including: a main stabilizer including a first charge/discharge element and a first power converter; and a plurality of sub-stabilizers each including a second charge/discharge element, a charge element, or a discharge element, and a second power converter. The plurality of sub-stabilizers include a first sub-stabilizer and a second sub-stabilizer including the charge element. When the voltage of the DC bus is higher than a first charge threshold, the second power converter of the first sub-stabilizer supplies a current equal to a current target value obtained by the second power converter of the first sub-stabilizer from the DC bus to the charge element of the first sub-stabilizer.