Cascaded Power Module Control for Overtemperature Power Balancing
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Solution Overview
Problem
Cascaded modular multilevel energy conversion systems experience overheating issues when connected to the AC power grid, leading to reduced power output and economic losses due to decreased current, as existing solutions typically reduce total operating power to prevent malfunctions.
Innovation Solution
A method and device that detect overheated and underheated power modules within the system, redistribute power to maintain constant total operating power by decreasing the power of overheated modules and increasing that of underheated modules, allowing the system to operate in a constant power mode while regulating temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the total operating power is decreased to prevent overheating, then the overheating problem is alleviated, but the electricity production and economic benefits are reduced
Solution Approach 1:
The patent segments the power conversion system into multiple independently controllable power modules. By monitoring the operating temperature of each module individually, the system can identify which specific modules are overheating and which have spare thermal capacity. This segmentation enables selective power redistribution rather than uniform power reduction, allowing the system to maintain higher total power output while preventing overheating in specific modules.
Solution Approach 2:
The patent applies local quality control by adjusting the operating power of individual power modules based on their specific thermal conditions. Modules with lower temperatures receive increased power allocation, while overheated modules receive reduced power. This localized approach ensures that each module operates within its thermal constraints while maximizing the overall system productivity, rather than uniformly reducing power across all modules.
2Temperature
If the current output to the AC power grid is reduced to prevent overheating, then the overheating issue is resolved, but the power output and economic losses increase
Solution Approach 1:
The patent implements dynamic power redistribution by continuously monitoring the operating temperatures of all power modules and adjusting their power allocation in real-time. When certain modules are identified as overheated, the system dynamically transfers their power load to cooler modules, maintaining constant total power output. This dynamic adjustment allows the system to respond to changing thermal conditions while preserving maximum power output to the AC grid.
Solution Approach 2:
The patent changes the operating parameters (power levels) of individual power modules based on their thermal state. By modifying the power input/output parameters of specific modules rather than the entire system, the patent maintains optimal total power output while preventing any single module from exceeding its thermal limits. This parameter-based control enables the system to avoid economic losses associated with reduced power output.
Data Source
AI summary
An energy conversion system, and a method and a device for controlling the energy conversion system at an overtemperature are provided. The energy conversion system includes at least one power conversion circuit each including at least two power modules that are cascaded. Respective operating temperatures of all the power modules are measured in real time, to determine the overheated power module that is operating at an overtemperature and the underheated power module that is operating at a normal temperature. Once an overheated power module is detected, a decreased power and a power difference for the overheated power module are acquired, and an increased power for the underheated power module is determined based on the power difference. The operating power of the overheated power module is decreased at the module level with the total operating power of the system remains constant or approximately constant.