Multilevel Power Converter Control With Estimated Input Voltages
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Solution Overview
Problem
Existing multi-level energy converters are complex and costly, with uncoordinated switching leading to high losses and bulky output filters, and are limited by low operating frequencies and high sensor requirements, especially when dealing with a large number of energy sources.
Innovation Solution
An electronic control device with a main controller that estimates elementary input voltages and currents, allowing coordinated switching at high frequencies without reducing stability or precision, and reducing the number of sensors needed by using voltage sensors only, while maintaining efficient regulation of output voltages and currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If uncoordinated switching is used in each conversion module, then each module can independently regulate its output, but the total number of switchings increases and cumulative losses increase
Solution Approach 1:
The patent merges the switching control of multiple conversion modules by introducing a global sorting mechanism at the system level. The main controller collects switching requirements from all elementary controllers, sorts them globally based on voltage levels, and coordinates their execution to reduce cumulative switchings while maintaining independent regulation capability of each module.
2Volume of moving object
If high switching frequency is implemented, then output filter size can be reduced, but measurement and control complexity increases due to sensor requirements
Solution Approach 1:
The patent extracts the voltage measurement function from individual conversion modules and centralizes it at the system level. The main controller performs global voltage measurements and uses this information to coordinate switching across all modules, eliminating the need for complex sensor arrangements at each module while enabling high-frequency operation with reduced filter size.
3Loss of energy
If coordinated switching is implemented across all modules, then cumulative switchings are reduced and losses decrease, but control complexity and coordination requirements increase
Solution Approach 1:
The patent introduces a main controller as an intermediary between elementary controllers and the switching devices. This mediator collects switching requirements from all modules, performs global sorting based on voltage levels, and distributes coordinated switching commands back to the elementary controllers, reducing cumulative switchings while managing control complexity through centralized coordination.
4Power
If a large number of conversion modules are connected in series, then total output voltage increases, but the number of sensors and control complexity increases proportionally
Solution Approach 1:
The patent makes the main controller universal by giving it multiple functions: global voltage measurement, coordination of switching across all modules, sorting of switching requirements, and centralized control. This multi-functional approach allows the system to handle a large number of conversion modules connected in series without proportionally increasing sensor and control complexity, as the main controller manages all modules through a unified control architecture.
Data Source
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AI summary
This electronic control device drives a power converter that delivers a total output voltage and/or output current from a plurality of elementary DC input voltages, each derived from a respective power source. The converter comprises several conversion modules, each receiving an elementary DC input voltage from a respective source and delivering an elementary output voltage; the conversion modules are connected in series via their outputs, and the total output voltage is equal to the sum of the elementary output voltages; each conversion module has several switches to convert the elementary DC input voltage into the respective elementary output voltage.The control system comprises several elementary controllers and a master controller connected to the elementary controllers. Each elementary controller is associated with a respective conversion module and controls the switches of that module. The master controller regulates the converter's output by sending control commands to the elementary controllers. This regulation is based on sets of elementary variables, each associated with a respective conversion module. Each elementary controller regularly measures values of these sets of variables for its associated conversion module and then transmits them to the master controller. These values include the elementary DC input voltage.The main controller includes a first estimator which calculates, for each conversion module, an estimated value of the elementary DC input voltage from a previously measured value of the elementary DC input voltage.