Electric Drive Control via Stored Optimal Inverter Parameters
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Solution Overview
Problem
The efficiency of electric drives depends on various variables such as output voltage and switching frequency of the inverter, but accurate motor parameters are often unknown, making it difficult to determine optimal operating parameters.
Innovation Solution
A method and apparatus for controlling an electric drive that involves running the drive in a desired operating point, determining the input power, varying the output voltage or flux reference to minimize power consumption, determining the optimal switching frequency, and storing these values for later use, allowing the drive to operate efficiently without requiring precise motor parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If numerical computing is used to determine optimal operating parameters, then the electric drive efficiency can be improved, but accurate motor parameters are required which are often unavailable
Solution Approach 1:
The system performs self-characterization by automatically determining optimal operating parameters through measurement and storage during commissioning, without requiring external motor parameter data. The electric drive characterizes itself by measuring input power at different operating points and storing the results for future use.
Solution Approach 2:
The optimal operating parameters are determined in advance during a commissioning phase before normal operation begins. The system pre-characterizes the electric drive by measuring and storing optimal parameters for various operating points, so that during normal operation these pre-determined parameters can be directly applied without requiring real-time calculations or motor parameter knowledge.
2Ease of operation
If optimal operating parameters are determined through measurement and storage, then the drive can operate efficiently without accurate motor parameters, but additional measurement and storage steps are required
Solution Approach 1:
The system performs the complex measurement and parameter determination process in advance during commissioning. Once the optimal parameters are measured and stored for each operating point, the normal operation becomes simple - the controller only needs to retrieve the pre-stored parameters from memory and apply them, eliminating the need for complex real-time calculations or motor parameter knowledge.
Data Source
AI summary
A method for controlling an electric drive, having an inverter, an electric motor and control means configured in a first operating state of the electric drive to control the electric drive to run in a constant operating point, determine and store a value of an output voltage of the inverter or a value of a flux reference of the inverter, and a value of a switching frequency of the inverter with which a determined input power of the electric drive is lowest. The controller is configured in a second operating state of the electric drive to control the electric drive to use the stored values to run in the operating point.