Model Predictive Control for Multi-Level Power Converters

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Solution Overview

Problem

Conventional power converter control methods, such as PI control, face challenges in efficiently managing multiple control parameters and maintaining closed-loop performance due to computational demands and switch timing constraints, especially in advanced control algorithms for multi-level power converters.

Innovation Solution

The implementation of model predictive control (MPC) using a plurality of switching matrices to select and adjust the switching states of power converter switches based on a multi-objective function, optimizing switch timing and minimizing errors, switching frequency, and DC bus voltage balancing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If model predictive control is implemented to optimize multiple control parameters, then control performance and efficiency are improved, but computational complexity and implementation difficulty increase

Engineering Contradiction:
Improvecontrol performanceVSAvoidcomputational complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The control algorithm is segmented into modular components: state prediction module, cost function evaluation module, and switching matrix selection module. Each module handles specific computational tasks independently, reducing overall complexity while maintaining optimization capability across multiple control parameters

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Switching matrices are pre-calculated and stored based on predicted future states of the power converter. This preliminary action allows the controller to quickly select optimal switching sequences without real-time computational burden, improving control performance while reducing implementation complexity

Inventive Principle:
Principle #10Preliminary action

2Reliability

If advanced control algorithms are used to monitor multiple control parameters simultaneously, then closed-loop performance is improved, but computational demands increase

Engineering Contradiction:
Improveclosed-loop performanceVSAvoidcomputational demands
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The most computationally intensive calculations are extracted from the real-time control loop and performed offline or in advance. Switching matrices and optimal control sequences are pre-determined based on system models, reducing real-time computational demands while maintaining reliable closed-loop performance through multi-parameter monitoring

Inventive Principle:
Principle #2Taking out (Extraction)

3Loss of energy

If switching frequency is reduced to minimize losses, then energy efficiency is improved, but current tracking quality deteriorates

Engineering Contradiction:
Improveswitching lossesVSAvoidcurrent tracking quality
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The switching frequency is made dynamic rather than fixed. The controller adapts switching frequency based on operating conditions, load requirements, and current tracking needs. This allows the system to minimize switching losses during light loads while maintaining high current tracking quality during dynamic transitions or heavy loads

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS10459472B2Model predictive control optimization for power electronics
Publication Date: 2019.10.29 HAMILTON SUNDSTRAND CORP
  • US10459472B2 patent drawing
  • US10459472B2 patent drawing
  • US10459472B2 patent drawing

AI summary

Embodiments are directed to a model predictive control for power electronics. The model predictive control includes a plurality of switching matrices defining potential states of a plurality of power converter switches of a multi-level power converter and a control. The control is configured to select a current switching matrix from the switching matrices that models the multi-level power converter in a current state. The control determines a targeted switching matrix from the switching matrices that best aligns with a targeted state based on alignment with a multi-objective function and changes with respect to the current state. The control adjusts a switch state of the power converter switches based on the targeted switching matrix. The control sets the current switching matrix to the targeted switching matrix and monitoring for changes with respect to the multi-objective function and the current state.