MVDC Collector System With Adaptive DC/DC Converter
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Solution Overview
Problem
Existing renewable energy power generation facilities, particularly solar power generation facilities, face high construction and maintenance costs due to the need for numerous DC-to-AC power converters and step-up transformers, and lack flexibility in voltage and power regulation, which limits the integration of maximum power point tracking (MPPT) features and fault protection.
Innovation Solution
The implementation of a medium voltage direct current (MVDC) collector system that uses isolable DC/DC power converters with high-frequency transformers and adaptive full-bridge/half-bridge operation, enabling efficient voltage and power conversion, MPPT integration, and rapid fault isolation by eliminating individual DC/AC converters and transformers, and employing diodes for unidirectional power flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If individual DC/AC power converters and step-up transformers are used for each string, then voltage and power conversion is achieved, but construction and maintenance costs are substantially increased
Solution Approach 1:
The patent merges multiple individual DC/AC power converters and step-up transformers into a single centralized power conversion system. Multiple PV strings are connected in parallel to a common DC/AC converter, eliminating the need for separate converters and transformers for each string. This consolidation directly reduces construction and maintenance costs while decreasing the overall number of power conversion devices in the system.
Solution Approach 2:
The centralized power conversion system performs multiple functions: it converts DC power from multiple PV strings to AC power, provides voltage step-up, and incorporates fault protection mechanisms for the entire array. This multi-functional approach replaces the need for multiple specialized devices, reducing both cost and complexity while maintaining comprehensive power conversion capability.
2Reliability
If circuit breakers are used for fault protection, then fault isolation is achieved, but voltage and power control mechanisms are limited
Solution Approach 1:
The patent implements dynamic voltage and power control mechanisms within the centralized power conversion system, allowing real-time adjustment of operating parameters. The system can dynamically regulate voltage levels and power output based on grid requirements and PV array conditions, providing continuous adaptability rather than fixed circuit breaker protection. This enables fine-grained control while maintaining fault protection capabilities.
Solution Approach 2:
The power conversion system incorporates feedback control mechanisms that continuously monitor voltage, power, and fault conditions. Based on this feedback, the system automatically adjusts its operation to maintain optimal performance and provide appropriate fault protection. This feedback-based control provides both adaptability and reliability, allowing the system to respond dynamically to changing conditions while maintaining robust fault isolation capabilities.
3Device complexity
If low frequency switching rates are used in DC/AC power converters, then device simplicity is maintained, but MPPT feature integration is inhibited
Solution Approach 1:
The patent changes the switching frequency parameter of the power converter to enable MPPT functionality. By operating at higher switching frequencies, the system can rapidly adjust its operation to track the maximum power point of the PV arrays. This parameter change allows the integration of advanced control features like MPPT without fundamentally altering the basic converter structure, maintaining relative simplicity while gaining adaptability.
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 solution significantly reduces balance of plant costs, enhances energy efficiency, and provides granular control and fault tolerance by integrating MPPT features and enabling flexible voltage and power management within the power conversion systems, while rapidly isolating faults and improving overall system performance.
Implementation Method 1
isolable DC/DC power converters with high-frequency transformers
Implementation Method 2
employing diodes for unidirectional power flow
Data Source
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AI summary
A medium voltage direct current (MVDC) collector system for renewable power generation facilities includes at least one renewable energy generation device (206). The MVDC collector system also includes at least one direct current (DC)-to-DC (DC/DC) power converter (208, 300, 500, 600) coupled to the at least one renewable energy generation device. The at least one DC/DC power converter is configured to shift a switching operation of the DC/DC power converter between full-wave conversion and half-wave conversion. The MVDC collector system further includes at least one controller (252) coupled to the at least one DC/DC power converter. The at least one controller is configured to regulate shifting the switching operation of the at least one DC/DC power converter between full- wave conversion and half-wave conversion.