Cascade Power Module Control Without Communication Lines
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Solution Overview
Problem
Conventional cascade system distributed control methods require communication for voltage sharing control, leading to reliability issues due to dependence on communication lines, which can fail, necessitating a solution that maintains stability without communication.
Innovation Solution
A non-communication distributed control method and device that regulates bridge arm voltage amplitudes through closed-loop control, using AC current as a reference, and adjusts the voltage amplitude based on feedback signals, ensuring consistent power absorption across modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional voltage sharing control method is used with communication lines, then voltage consistency can be achieved, but system reliability deteriorates due to communication failure risk
Solution Approach 1:
The patent extracts and eliminates the communication line dependency from the voltage sharing control system. Each power module independently controls its bridge arm voltage amplitude without requiring communication with other modules, thereby removing the reliability bottleneck while maintaining voltage consistency through autonomous closed-loop control
Solution Approach 2:
Each power module performs self-service voltage sharing control by independently monitoring its own bridge arm voltage amplitude and autonomously adjusting it to match the reference value. The system achieves coordinated control without external communication through self-contained closed-loop regulation at each module
2Measurement precision
If communication lines are mounted for voltage sharing control, then control precision is improved, but system complexity increases
Solution Approach 1:
The patent removes the communication line infrastructure from the system architecture. Voltage sharing control is achieved through local measurement and control at each power module, eliminating the need for complex communication networks while maintaining control precision
Solution Approach 2:
The control function is segmented and distributed to each power module independently. Each module contains its own voltage measurement and control circuitry, allowing autonomous voltage sharing control without centralized communication, thereby simplifying the overall system architecture
Data Source
AI summary
The application provides a cascade system distributed control method and device. The method including: taking an output of a closed-loop control for regulating an AC current of the power module as a reference value of a bridge arm voltage; according to the reference value of the bridge arm voltage to obtain an amplitude of the bridge arm voltage, taking the amplitude of the bridge arm voltage as a feedback signal, and after closed-loop control and regulation together with the AC current of the power module, adjusting the reference value of the bridge arm voltage; and controlling the bridge arm voltage according to the reference value of the bridge arm voltage, wherein in at least one working mode of the cascade system, a change of parameters reflecting an active current has a monotonic relation with a change of the amplitude of the bridge arm voltage.