Photovoltaic DC Bus Control With Distributed MPPT Handoff
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Solution Overview
Problem
Solar power generation systems face inefficiencies and high costs in transmitting and storing power due to the limitations of maximum power point tracking (MPPT) in photovoltaic (PV) arrays, particularly in integrating energy storage systems and managing power distribution among multiple DC/DC controllers.
Innovation Solution
The implementation of a PV bus and fixed DC bus power system with distributed multiagent maximum power tracking methods, including control mode handoff and adaptive ΔV MPPT control, allows for redundancy among DC/DC controllers, enabling efficient MPPT operations and power management by scaling voltage perturbations based on local device metrics, and utilizing a central inverter unit with distributed DC/DC controllers to optimize power tracking and sharing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If distributed MPPT control is implemented among multiple DC/DC controllers, then system reliability and redundancy are improved, but control complexity and coordination overhead increase
Solution Approach 1:
The patent divides the centralized MPPT control function into multiple distributed DC/DC controllers, with each controller capable of performing MPPT independently. This segmentation allows the system to maintain reliability through distribution while managing complexity through modular control units that can operate autonomously or in coordination as needed
Solution Approach 2:
The patent implements communication and coordination mechanisms among distributed DC/DC controllers, enabling them to share state information and coordinate their MPPT operations. This feedback loop allows controllers to adjust their behavior based on system-wide conditions, maintaining stability and reliability while managing the complexity of distributed control through structured information exchange
2Stability of the object's composition
If sequential MPPT handoff between DC/DC controllers is implemented, then system stability is improved, but response time and productivity decrease
Solution Approach 1:
The patent implements a timer-based mechanism that periodically evaluates whether to hand off MPPT control to the next DC/DC controller in the sequence. This periodic action ensures stable transitions between controllers by using predetermined time intervals, preventing erratic switching while maintaining the ability to respond to changing conditions through structured periodic evaluation
Solution Approach 2:
The patent establishes a predetermined sequence of DC/DC controllers ready to perform MPPT in advance. When a controller completes its MPPT cycle or a handoff condition is met, the next controller in the pre-established sequence is already positioned to take over, eliminating delays associated with selecting and configuring new controllers during operation
3Measurement precision
If adaptive voltage perturbation scaling is used in MPPT, then measurement precision and control accuracy are improved, but computational requirements and device complexity increase
Solution Approach 1:
The patent implements adaptive voltage perturbation scaling where the magnitude of voltage changes during MPPT is dynamically adjusted based on measured power responses. The controller scales the perturbation size according to observed system behavior, increasing precision by using smaller steps when near the maximum power point and larger steps when further away, while managing complexity through adaptive algorithms that respond to real-time measurements
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 enhances the efficiency and stability of solar power systems by ensuring reliable MPPT operations, reducing system instability, and improving energy yield while simplifying control design and reducing costs through standardized power interconnections and modular inverters.
Implementation Method 1
photovoltaic (PV) panels arranged in an array or string typically provide the means to convert solar energy into electrical energy
Data Source
AI summary
Solar power systems and methods utilize DC power transmission and centralized power inversion. The solar power systems include a photovoltaic (PV) bus system and a fixed bus system. The PV system utilizes a control mode handoff control method, which includes determining that a local maximum power point tracking (MPPT) control is enabled; in response to determining that the local MPPT control is enabled, starting an MPPT mode timer; performing local MPPT; determining that the MPPT mode timer is greater than a predetermined period; and, in response to determining that the MPPT mode timer is greater than a predetermined period, handing off MPPT control to the next MPPT controller. The distributed MPPT control method may include sequential MPPT control, adaptive ΔV MPPT control, and/or power limiting control. The fixed bus system includes PV string-level MPPT controllers and a fixed DC input central inverter or multiple fixed DC modular inverters.