Shutdown Control Circuit for Distributed Power Systems
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Solution Overview
Problem
In distributed power generation systems, existing electrical shock protection solutions fail to ensure reliable disconnection of direct current power supplies due to communication link faults, leading to frequent disconnections during temporary or random abnormal conditions, which affects the usability of the system.
Innovation Solution
A shutdown control system with a main circuit and control circuit, including a system control unit, transformation control unit, and power source control units, which periodically transmit communication signals to determine the operation mode of shutdown circuits based on the system's state, ensuring the output voltage falls within a secure range even if the communication link is broken.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shutdown circuit disconnects the direct current power supply when the communication link is broken, then the electrical shock protection is ensured, but the direct current power supply is frequently disconnected during temporary or random abnormal conditions, affecting the usability of the system
Solution Approach 1:
The shutdown circuit dynamically adjusts its response based on the operational state of the power generation system. When the system is in the power generation state, temporary communication failures do not trigger disconnection. When the system is in the shutdown state, communication failures do trigger disconnection to ensure safety. This dynamic state-dependent behavior resolves the contradiction between ensuring protection and maintaining usability.
Solution Approach 2:
The control logic changes the threshold for triggering shutdown based on the operational state parameter. In the power generation state, a higher threshold is used (communication failure alone is insufficient). In the shutdown state, a lower threshold is used (communication failure is sufficient). This parameter change allows the system to be more tolerant of communication issues during operation while remaining sensitive during shutdown, resolving the contradiction.
2Ease of operation
If the shutdown circuit requires receiving communication signal from the system control unit to operate in normal mode, then unnecessary disconnections are prevented, but the system complexity increases due to additional control logic and signal monitoring
Solution Approach 1:
The power source control unit performs multiple functions: it monitors communication signals from the system control unit, detects the operational state of the power generation system, and controls the shutdown circuit based on the combination of these inputs. By consolidating these functions in a single control unit, the patent achieves the desired usability improvement without proportionally increasing overall system complexity.
Solution Approach 2:
The shutdown circuit uses its own operational state information (power generation state vs. shutdown state) to determine how to respond to communication signals. This self-service capability allows the circuit to autonomously make decisions about when to disconnect, reducing the need for complex external control logic and minimizing system complexity while maintaining usability.
Data Source
AI summary
A shutdown control system and a shutdown control method are provided. A shutdown unit is a series circuit of multiple shutdown circuits connected in series or a series-parallel circuit of multiple such series circuits connected in parallel. Each shutdown circuit is connected to at least one direct current power supply. A SCU periodically transmits a first communication signal until receiving a first user command. A TCU controls states of a electrical energy transforming unit to control the operation state of a power generation system. Each PCU determines whether the first communication signal is received during a preset time period and whether the distributed power generation system operates in a power generation state, and controls a corresponding shutdown circuit to operate in a normal operation mode if at least one of the conditions is met; and otherwise operate in a security mode.